List of Bacteria Associated with Infection in Humans

A check list of bacteria associated with infection in humans. See below for comprehensive table.

In addition to the relatively small number of well-known pathogenic bacteria that are able to infect otherwise healthy people, e.g. Staphylococcus aureus, Mycobacterium tuberculosis, and Streptococcus pyogenes, there is a steadily growing list of less well known organisms, many of which are able to cause disease only under special circumstances.

All bacteria associated with infections in humans are listed in the table that forms the bulk of this chapter, which has been designed to serve as a single port of call for clinicians who seek concise information on the less well known clinically significant bacteria. Every name in the table has been checked to see that it has ‘standing in nomenclature’: widely used names that do not have standing in nomenclature (at the time of writing) are included, but written in inverted commas (e.g. ‘Spirillum minus’ – one of the causes of rat bite fever).

For an up to date check on nomenclature, the reader is referred to

Reported antibiotic susceptibilities and treatments are listed as a rough guide only: for some organisms the only available published information consists of in vitro test results for small numbers of strains, or apparent clinical response to therapy for a single case. There is no substitute for the determination of the susceptibilities of organisms as they are cultured on a case by case basis in tandem with the monitoring of therapeutic response.

Geographical restriction and particular exposures—some pathogenic bacteria, e.g. Burkholderia pseudomallei (the cause of melioidosis), are associated with special geographical areas; others are associated with particular forms of exposure, e.g. some Actinobacillus species with animal bites, and Rickettsia species with tick bites.

Bacterial commensals and usually harmless environmental organisms as causes of disease—given the right kind of help, bacteria that live usually as harmless human commensals can cause disease, e.g. skin commensals such as Staphylococcus epidermidis can cause line sepsis and infect prosthetic devices; gut commensals such as Bacteroides species can grow in abscesses; and oral commensals such as Streptococcus salivarius can cause endocarditis. Immunosuppressed patients, ventilated patients, and patients undergoing continuous ambulatory peritoneal dialysis are vulnerable to infection by a wide range of otherwise harmless environmental organisms.

Improved understanding of disease processes and discovery of ‘new’ pathogens—a refined understanding of, e.g. periodontal disease, has resulted in the characterization of new organisms such as Pseudoramibacter alactolyticus, Johnsonella ignava, Centipeda periodontii, and Capnocytophaga gingivalis: some of these have subsequently been identified in systemic infections such as bacteraemia.

Impact of new laboratory techniques—these have revealed the presence of new species and new disease associations, e.g. Tropheryma whipplei was associated with Whipple’s disease by molecular methods before the organism was cultured; molecular methods have detected oddities like Bradyrhyzobium elkanii in aortic aneurysm tissue, although its role as potential pathogen is doubtful.

Changes in nomenclature—amidst the discovery of new bacteria, taxonomic rearrangements and changes in nomenclature pile on additional layers of confusion for the clinician. For example, it has been recognized that organisms formerly known as Burkholderia cepacia are actually a complex of several genomospecies, which have been given individual names. It is also confusing when a well-known genus is split to reflect the recognition that its composite species are a number of groups that are only distantly related, e.g. many organisms that were once known as Bacteroides species. New organisms will continue to be described and name changes will continue to occur.

Table 1 A check list of bacteria associated with infection in humans
Nomenclature Associated infections Reported susceptibilities and treatments Notes
Genus Species and subspecies
(synonyms, CDC alphanumeric groups)
Abiotrophia adiacens—see Granulicatella adiacens]
Abiotrophia A. defectiva Endophthalmitis, brain abscess, osteomyelitis, peritonitis, endocarditis Vancomycin, ceftriaxone (plus gentamicin or rifampicin) Previously known as nutritionally deficient or variant streptococci
[Abiotrophia elegans—see Granulicatella elegans]
[‘Abiotrophia para-adiacens’—see Granulicatella notes]
Achromobacter (Alcaligenes)
  • A. denitrificans
  • A. insolitus
  • A. piechaudii
  • A. ruhlandii
  • A. spanius
  • A. xylosoxidans
Septicaemia, CAPD peritonitis, pneumonia, ear infection, pulmonary infection in cystic fibrosis, keratitis, vascular line sepsis Ureidopenicillins, ceftazidime, carbapenems  
[Achromobacter CDC group Vd and Achromobacter groups A, C, and D—see Ochrobactrum]
[Achromobacter groups B and E—see Pannonibacter]
Acidaminococcus A. fermentans Abscesses, postsurgical infections Metronidazole  
Acidovorax (Pseudomonas)
  • A. avenae
  • A. delafieldii
  • A. facilis
  • A. temperans
Wound infection, UTI, bacteraemia, meningitis, septic arthritis    
  • A. baumannii
  • A. calcoaceticus
  • A. haemolyticus
  • A. johnsonii
  • A. junii
  • A. lwoffi
  • A. parvus
  • A. radioresistens
  • A. schindleri
  • A. ursingii
Septicaemia, UTI, wound infections, abscesses, endocarditis, meningitis, osteomyelitis Aminoglycosides, ureidopenicillins, ceftazidime, carbapenems, tigecycline May be multiresistant. Nosocomial outbreaks reported. Infections associated with debilitated patients
Actinobacillus A. actinomycetemcomitans (Haemophilus actinomycetemcomitans) Periodontitis, endocarditis, abscesses, pericarditis, meningitis Penicillin (plus gentamicin for endocarditis) Human oral commensal. The genus Aggregatibacter has been proposed to accommodate A. actinomycetemcomitans and some Haemophilus spp.
  • A. equuli
  • A. lignieresii
  • A. suis
Wound infection, abscesses, endocarditis, meningitis Ampicillin (plus gentamicin for endocarditis) Associated with animal contact and bites
  A. hominis Septicaemia, empyema Amoxicillin–clavulanate  
  A. ureae (Pasteurella ureae) Meningitis, pneumonia, endocarditis, hepatitis, peritonitis Ampicillin (plus gentamicin for endocarditis), chloramphenicol Respiratory tract commensal in humans
  • A. massiliense
  • A. schaalii
  • A. urinale
Pyelonephritis, UTI, septicaemia, superficial skin infection Penicillin, cefuroxime, nitrofurantoin, tetracycline, clindamycin  
  • A. Latina
  • A. madurae
  • A. pelletieri
  • A. vinacea
Actinomycetoma, Madura foot Co-trimoxazole, dapsone  
  • A. cardiffensis
  • A. dentalis
  • A. europaeus
  • A. funkei
  • A. georgiae
  • A. gerencseriae
  • A. graevenitzii
  • A. hongkongensis
  • A. israelii
  • A. meyeri
  • A. naeslundii
  • A. neuii neuii
  • A. neuii anitratus
  • A. odontolyticus
  • A. oricola
  • A. radicidentis
  • A. radingae
  • A. turicensis
  • A. urogenitalis
  • A. viscosus
Actinomycosis β-Lactams  
Advenella A. incenata Pulmonary infection, bacteraemia    
  • A. sanguinicola
  • A. urinae
  • A. urinaehominis
  • A. viridans
Endocarditis, UTI, wounds, meningitis, abscesses, CAPD peritonitis, lymphadenitis, spondodactylitis Penicillin, vancomycin (plus gentamicin for endocarditis)  
  • A. allosaccharophila
  • A. bestiarumA. Caviae
  • A. enteropelogenes
  • A. hydrophila
  • A. jandaei
  • A. media
  • A. salmonicida
  • A. schubertii
  • A. trota (A. tructi)
  • A. veronii
Wound infection, abscesses, septicaemia, meningitis, leech-bite infection, alligator-bite infection, acute diarrhoea Aminoglycosides, chloramphenicol, ceftazidime, co-trimoxazole Infections associated with aquatic exposure. A. veroniiincludes biovars Veronii and Sobria. The taxonomic status of some species is unclear. The status of A. allosaccharophila is controversial. A. trota may be a synonym of A. enteropelogenes
Afipia A. felis Cat-scratch disease Imipenem, aminoglycosides Cat-scratch disease is associated also with Bartonella spp.
A. broomeae Bone marrow infection, septic arthritis Imipenem, aminoglycosides Role as pathogen uncertain
A. clevelandensis Bone infection Imipenem, aminoglycosides Role as pathogen uncertain
  • A. birgiae
  • A. massiliensis
Pneumonia Imipenem, aminoglycosides Roles as pathogens uncertain
Agrobacterium A. radiobacter (A. tumefaciens) Endocarditis, CAPD peritonitis, UTI, line sepsis Co-trimoxazole, gentamicin, amikacin, piperacillin-tazobactam The nomenclature of this taxon is unsettled. The names A. tumefaciens and A. radiobacter both have standing in nomenclature. Transfer of Agrobacterium to Rhizobium has been proposed
[Alcaligenes denitrificans—see Achromobacter denitrificans]    
  • A. faecalis
  • A. latus
Pneumonia, otitis, UTI, osteomyelitis, bacteraemia Amoxicillin–clavulanate, cephalosporins, fluoroquinolones  
[Alcaligenes xylosoxidans—see Achromobacter xylosoxidans xylosoxidans]
[Alcaligenes piechaudii—see Achromobacter piechaudii]
[Alcaligenes ruhlandii—see Achromobacter ruhlandii]
Alishewanella A. fetalis From fetal necropsy specimen   Clinical significance uncertain
  • A. finegoldii (Bacteroides finegoldii)
  • A. onderdonkii
  • A. putredinis (Bacteroides putredinis)
  • A. shahii
Appendicitis, peritonitis, abdominal abscess Metronidazole, ertapenem β-Lactamase producers. Abdominal infections, found in association with other anaerobes
Alloiococcus A. otitis (Alliococcus otitis) Otitis media Vancomycin  
[Amycolata autotrophica—see Pseudonocardia autotrophica]
Amycolatopsis A. orientalis (Nocardia orientalis)     Role as pathogen uncertain
A. palatopharyngis Palatopharyngeal infection   Clinical significance poorly defined
  • A. succiniproducens
  • A. thomasii
Diarrhoea, bacteraemia Cefuroxime, tetracycline, chloramphenicol Infection may be related to exposure to cat or dog faeces
Anaerococcus (Peptostreptococcus)
  • A. hydrogenalis
  • A. lactolyticus
  • A. octavius
  • A. prevotii
  • A. tetradius
  • A. vaginalis
Mixed anaerobic infections, abscesses β-Lactams, metronidazole  
Anaeroglobus A. geminatus From postoperative collection   Role as pathogen uncertain
Anaerorhabdus (Bacteroides) A. furcosus Lung abscess, appendix and abdominal abscesses    
[‘Anguillina coli’—see Serpulina pilosicoli]
Anaplasma A. phagocytophilum Anaplasmosis Doxycycline Previously known as human granulocytic ehrlichiosis
[Arachnia propionica—see Propionibacterium propionicus]
Arcanobacterium A. haemolyticum (Corynebacterium haemolyticum) Tonsillitis, cellulitis, lymphadenopathy, brain abscess, septicaemia, osteomyelitis Penicillin, erythromycin  
A. bernardiae (Actinomyces bernardiae) UTI, septicaemia, septic arthritis β-Lactams Previously known as CDC coryneform group 2
A. pyogenes (Actinomyces pyogenes) Septic arthritis β-Lactams  
Arcobacter (Campylobacter)
  • A. butzleri
  • A. cryaerophilus
Abdominal cramps, diarrhoea   Self-limiting
  • A. albus
  • A. creatinolyticus
  • A. cumminsii
  • A. luteolus
  • A. oxydans
  • A. scleromae
  • A. woluwensis
UTI, bacteraemia, skin infection Vancomycin, penicillins Arthrobacter sp. has been implicated in Whipple’s syndrome, a disease usually associated with Tropheryma whipplei
  • A. minutum (Lactobacillus minutus)
  • A. parvulum (Streptococcus parvulus)
  • A. rimae (Lactobacillus rimae)
UTI, dental abscesses, pelvic abscesses, wound infection   Isolates from periodontal sites suggest possible role in periodontal disease
  A. vaginae Bacterial vaginosis    
[Aureobacterium—see Microbacterium]
Azospirillum A. brasilense (Roseomonas fauriae) CAPD peritonitis, line sepsis Imipenem, aminoglycosides, ceftriaxone, ciprofloxacin  
Bacillus B. anthracis Anthrax Penicillin, erythromycin Ciprofloxacin for postexposure prophylaxis
[Bacillus brevis—see Brevibacillus agri]
  • B. circulans
  • B. coagulans
  • B. megaterium
  • B. mycoides
  • B. sphaericus
  • B. thuringiensis
Pneumonia, septicaemia, corneal infections, meningitis, food poisoning, eye infection, lung infection Vancomycin, clindamycin, aminoglycosides, imipenem, penicillin Other than the well-known B. anthracis and B. cereus, Bacillus spp. are rare causes of focal and systemic sepsis. Some isolates are resistant to vancomycin. Isolates may represent specimen or laboratory contamination. B. thuringiensis is a biological insecticide which has caused corneal infection
  • B. cereus
  • B. licheniformis
  • B. pumilus
  • B. subtilis
Food poisoning, wound infection, cutaneous lesions, bacteraemia, endocarditis, eye infection Clindamycin, vancomycin, gentamicin Diarrhoea is self-limiting. B. cereus is resistant to β-lactams
  • B. caccae
  • B. capillosus
  • B. coagulans
  • B. eggerthii
  • B. finegoldii
  • B. fragilis
  • B. massiliensis
  • B. nordii
  • B. ovatus
  • B. pyogenes
  • B. salyersae
  • B. splanchinicus
  • B. stercoris
  • B. tectus
  • B. thetaiotaomicron
  • B. uniformis
  • B. ureolyticus
  • B. vulgatus
Abscesses, bacteraemia, bite infections, wound infections, chronic otitis media, pelvic inflammatory disease, neonatal sepsis Ureidopenicillins, carbapenems, metronidazole Resistance to metronidazole and β-lactams has been reported. Many species previously classified as Bacteroides have been transferred to other genera: see Alistipes, Anaerorhabdus, Campylobacter, Dialister Mitsuokella, Parabacteroides, Prevotella, Porphyromonas, and Tannerella
Balneatrix B. alpica Pneumonia, bacteraemia, meningitis Ceftriaxone, ofloxacin, amoxicillin, netilmicin Infection associated with exposure to hot spring water
Bartonella B. bacilliformis Oroya fever, verruga peruana Chloramphenicol, streptomycin  
B. elizabethae (Rochalimaea elizabethae) Endocarditis Gentamicin, imipenem, co-trimoxazole  
  • B. clarridgeiae
  • B. henselae (Rochalimaea henselae)
Cat-scratch disease, bacillary angiomatosis Aminoglycosides, doxycycline Cat-scratch disease is associated also with Afipia felis
B. quintana (Rochalimaea quintana) Trench fever, bacillary angiomatosis Aminoglycosides, doxycycline  
B. schoenbuchensis Deer ked dermatitis   Evidence to associate this organism with deer ked dermatitis is circumstantial
B. vinsonii arupensis Bacteraemia Ceftriaxone Zoonosis from rodents
Bergeyella B. zoohelcum (Weeksella zoohelcum) Wound infection, septicaemia, meningitis Cefotaxime, penicillins, ciprofloxacin, tetracycline Associated with dog and cat bites
  • B. adolescentis
  • B. angulatum
  • B. bifidum
  • B. dentium
  • B. longum (B. infantis)
  • B. pseudocatenulatum
Bacteraemia, abscesses, peritonitis, otitis, paronychia Clindamycin, penicillins, cefoxitin Reported risk factors include surgery, malignancy, steroid therapy, intravenous drug use, and acupuncture. Some strains used as probiotics
[Bifidobacterium inopinatum—see Scardovia inopinata]
Bilophila B. wadsworthia Appendicitis, abscesses, bacteraemia, biliary tract sepsis, mastoiditis Metronidazole, amoxicillin/clavulanate, ureidopenicillins, cephalosporins  
Bordetella B. bronchiseptica Respiratory tract infection Tetracycline, fluoroquinolones Zoonosis from dogs and other animals
  • B. hinzii
  • B. holmesii
  • B. trematum
Bacteraemia, otitis, wound infection   B. hinzii is a pathogen of poultry
  • B. parapertussis
  • B. pertussis
Whooping cough, respiratory tract infection Erythromycin B. parapertussis causes less severe disease
  • B. afzelii
  • B. andersoni
  • B. bissettii
  • B. burgdorferi
  • B. garinii
  • B. japonica
  • B. lusitaniae
  • B. sinica
  • B. spielmanii
  • B. tanukii
  • B. turdi
  • B. valaisiana
Lyme disease Amoxicillin, doxycycline, ceftriaxone  
  • B. caucasica
  • B. crocidurae
  • B. duttonii
  • B. graingeri
  • B. hermsii
  • B. hispanica
  • B. latyschewii
  • B. mazzottii
  • B. parkeri
  • B. persica
  • B. recurrentis
  • B. turicatae
  • B. venezuelensis
Relapsing fever Tetracycline, erythromycin, chloramphenicol, penicillin B. recurrentis is louse-borne; other agents are tick-borne
Bosea B. massiliensis Linked with ventilator-associated pneumonia Doxycycline, telithromycin Amoeba-resisting bacterium from hospital water supplies
  • B. aalborgi
  • B. pilosicoli (Serpulina pilosicoli, ‘Anguillina coli’)
Intestinal spirochaetosis   Of uncertain significance
Bradyrhizobium B. elkanii Detected in tissue from aortic aneurysm   Potential role as pathogen uncertain
[Branhamella catarrhalis—see Moraxella catarrhalis]
Brevibacillus B. centrosporus Bacteraemia Vancomycin Previously confused with B. laterosporus and reported as such in clinical literature
B. parabrevis Bacteraemia, abscess Vancomycin  
  • B. casei
  • B. epidermidis
  • B. luteolum (B. lutescens)
  • B. mcbrellneri
  • B. otitidis
  • B. paucivorans
Bacteraemia, endocarditis, meningitis, chest infection, pericarditis, vascular catheter sepsis Glycopeptides  
Brevundimonas (Pseudomonas)
  • B. diminuta
  • B. vesicularis
Septicaemia, endocarditis Cefazolin, ceftriaxone, piperacillin (plus gentamicin for endocarditis)  
  • B. abortus
  • B. canis
  • B. melitensis
  • B. suis
Brucellosis Doxycycline (plus streptomycin or rifampicin) The four species names used for clinical purposes represent biovars of a single species, B. melitensis
Bulleidia B. extructa Necrotizing ulcerative periodontitis in HIV patients    
Burkholderia (Pseudomonas)
  • B. ambifaria
  • B. anthina
  • B. cenocepacia
  • B. cepacia (Pseudomonas cepacia)
  • B. dolosa
  • B. multivorans
  • B. pyrrocinia
  • B. stabilis
  • B. vietnamiensis
Lung infection in cystic fibrosis, bacteraemia, endocarditis, septic arthritis, UTI Ureidopenicillins, ceftazidime, aztreonam, carbapenems, fluoroquinolones, co-trimoxazole B. cepacia sensu stricto and other taxa listed are genomospecies of the B. cepacia species complex (B. cepacia sensu lato). Hard to differentiate by routine methods. Differences in disease progression in cystic fibrosis may relate to different genomospecies
B. gladioli (Pseudomonas gladioli) Lung infection in cystic fibrosis Ureidopenicillins, ceftazidime, aztreonam, carbapenems, fluoroquinolones, co-trimoxazole  
B. fungorum Septic arthritis, bacteraemia, meningitis Amoxicillin, cefuroxime, ceftazidime, ciprofloxacin, meropenem, co-trimoxazole  
B. mallei (Pseudomonas mallei) Glanders Sulfadiazine, co-amoxiclav, tetracycline, co-trimoxazole  
B. pseudomallei (Pseudomonas pseudomallei) Melioidosis Ceftazidime, co-trimoxazole, chloramphenicol, imipenem  
  • B. agrestis
  • B. noackiae
Appendicitis, wound infection Aminoglycosides, doxycycline Cephalosporin resistance reported
Butyrivibrio B. fibrisolvens Endophthalmitis Penicillin, chloramphenicol From rumina of farm animals
[Calymmatobacterium granulomatis—see Klebsiella granulomatis]
[Campylobacter butzleri—see Arcobacter butzleri]
[Campylobacter cinaedi—see Helicobacter cinaedi]
[Campylobacter fennelliae—see Helicobacter fennelliae]
[Campylobacter pyloridis—see Helicobacter pylori]
  • C. coli
  • C. jejuni jejuni
  • C. jejuni doylei
  • C. mucosalis
Gastroenteritis, bacteraemia Erythromycin, fluoroquinolones Infections are usually self-limiting
  • C. concisus
  • C. curvus (Wolinella curva)
  • C. gracilis (Bacteroides gracilis)
  • C. rectus (Wolinella recta)
  • C. showae
  • C. sputorum
Periodontitis, appendicitis, peritonitis, head and neck infections, abscesses Ureidopenicillins, amoxicillin/clavulanate, carbapenems, fluoroquinolones, metronidazole  
C. fetus fetus Fever, diarrhoea, meningoencephalitis, endocarditis, abscesses Erythromycin, ampicillin, chloramphenicol, gentamicin  
C. fetus venerealis Bacterial vaginosis   Role as human pathogen poorly defined. Reported from faeces of homosexual men
  • C. hyointestinalis
  • C. lari (C. laridis)
  • C. upsalensis
Diarrhoea, bacteraemia, abscess Erythromycin, ampicillin, gentamicin Zoonoses from mammals and birds
  • C. canimorsus (CDC DF-1)
  • C. cynodegmi (CDC DF-2)
  • C. gingivalis
  • C. granulose
  • C. haemolytica
  • C. ochracea
  • C. sputigena
  • Wound infection, septicaemia, abscesses, meningitis, endocarditis
  • Periodontitis, septicaemia
  • Penicillin
  • Penicillins, ciprofloxacin, tetracycline, chloramphenicol
  • From dog bites
  • From oral flora. Infections associated with malignancy and neutropenia
  • C. hominis
  • C. valvarum
Endocarditis, meningitis Penicillin (plus gentamicin for endocarditis)  
Catonella C. morbi Periodontitis, endodontic infection   Role as pathogen unclear
CDC EF-4   Bite infections β-Lactams  
  • C. davisae
  • C. lapagei
  • C. neterii
Bacteraemia Chloramphenicol, cefamandole, gentamicin Two other species (sp. 3 and sp. 5) have been isolated from clinical specimens
  • C. denverensis
  • C. hominis (CDC coryneform group A-3)
Bacteraemia, meningitis, pilonidal abscess, wound infection, homograft valve infection Clarithromycin, clindamycin, imipenem, minocycline, rifampicin, vancomycin  
[Cellulomonas cellulans—see Cellulosomicrobium]
[Cellulomonas turbata—see Oerskovia turbata]
  • C. cellulans (Cellulomonas cellulans, Oerskovi xanthineolytica)
  • C. funkei
Meningitis, pyonephrosis, CAPD peritonitis, endophthalmitis Vancomycin and gentamicin or rifampicin  
Centipeda C. periodontii Periodontitis   Role as pathogen unclear. Shown to inhibit lymphocytes
Chlamydia C. trachomatis Trachoma, genital infection, neonatal infection, lymphogranuloma venereum Erythromycin, tetracycline, azithromycin Includes 18 serovars clustered into two biovars: trachoma and lymphogranuloma venereum
Chlamydophila C. abortus (Chlamydia psittaci) Abortion   Associated with contact with infected ruminants
  C. pneumoniae (Chlamydia pneumoniae) Chest infection Tetracycline Infections in humans associated with biovars TWAR
  C. psittaci (Chlamydia psittaci) Psittacosis Tetracycline Zoonosis from birds
Chromobacterium C. violaceum Septicaemia, osteomyelitis, abscesses, eye infection Erythromycin, tetracycline, chloramphenicol, gentamicin Associated with exposure to soil and water
Chryseobacterium (Flavobacterium)
  • C. gleum
  • C. indologenes
Bacteraemia, abdominal sepsis, vascular catheter sepsis Piperacillin-tazobactam, minocycline, fluorquinolones, rifampicin Susceptibilities vary. Often multiresistant
[Chryseobacterium meningosepticum—see Elizabethkingia meningoseptica]
[Chryseomonas luteola—see Pseudomonas luteola]
  • C. amalonaticus
  • C. braakii
  • C. diversus
  • C. farmeri
  • C. freundii
  • C. gilenii
  • C. koseri
  • C. murliniae
  • C. rodentium
  • C. sedlakii
  • C. werkmanii
  • C. youngae
UTI, meningitis, bacteraemia, haemolytic–uraemic syndrome Aminoglycosides, β-lactams Variable susceptibility. May be multiresistant. Nosocomial outbreaks of infection reported. Citrobacter spp. are part of the normal faecal flora
  • C. argentinense
  • C. baratii
  • C. beijerinckii
  • C. bifermentans
  • C. bolteae
  • C. butyricum
  • C. cadaveris
  • C. carnis
  • C. celatum
  • C. clostridioforme
  • C. cochlearium
  • C. cocleatum
  • C. fallax
  • C. ghonii
  • C. glycolicum
  • C. haemolyticum
  • C. histolyticum
  • C. indolis
  • C. innocuum
  • C. irregulare
  • C. leptum
  • C. limosum
  • C. malenominatum
  • C. novyi
  • C. oroticum
  • C. paraputrificum
  • C. piliforme
  • C. putrefasciens
  • C. ramosum
  • C. sardiniense (C. absonum)
  • C. septicum
  • C. sordellii
  • C. sphenoides
  • C. sporogenes
  • C. subterminale
  • C. symbiosum
  • C. tertium
Wound infection, bacteraemia, abscesses Penicillin, clindamycin, metronidazole Many Clostridiumspp. have been isolated form clinical specimens. For most, their clinical significance is poorly defined. C. baratiiandC. butyricum are rare causes of botulism. C. fallax, C. histolyticum, C. novyi, C. septicum, and C. sordellii are gas-gangrene agents. Treatment of gas gangrene includes debridement and penicillin, clindamycin, or metronidazole
C. botulinum Botulism   Antitoxin and respiratory support as treatment
C. difficile Diarrhoea, pseudomembranous colitis Metronidazole, vancomycin Infection associated with antibiotic exposure
C. perfringens Food poisoning, necrotizing enterocolitis, gas gangrene   Debridement and penicillin, clindamycin, or metronidazole for treatment of gas gangrene
C. tetani Tetanus Metronidazole, penicillin Antitoxin and supportive treatment
Collinsella C. aerofaciens     From faecal flora. Clinical significance is undefined
[Comamonas acidovorans—see Delftia acidovorans]
Comamonas (Pseudomonas)
  • C. terrigena
  • C. testosteroni
Bacteraemia, UTI, conjunctivitis, endocarditis, wound infection, abdominal abscess, peritonitis, meningitis Ureidopenicillins, ceftazidime, ciprofloxacin, aminoglycosides, imipenem Infections in neutropenic patients. Infections associated with animal bite and exposure to tropical fish
  • C. accolens
  • C. afermentans
  • C. amycolatum
  • C. appendicis
  • C. argentoratense
  • C. atypicum
  • C. aurimucosum (C. nigricans)
  • C. auris
  • C. bovis
  • C. confusum
  • C. coyleae
  • C. durum
  • C. falsenii
  • C. freneyi
Septicaemia, peritonitis, UTI, eye infection, wound infection, endocarditis, osteomyelitis, septic arthritis, meningitis, abscesses Glycopeptides, β-lactam, erythromycin, rifampicin More than 40 Corynebacterium spp. have been isolated from clinical specimens. For many of them, clinical significance and empirical therapy are poorly defined. Many isolates are susceptible to β-lactams. Multiresistant, vancomycin-susceptible isolates of CDC coryneform group G-2, C. jeikeium and C. urealyticumhave been reported. Nosocomial outbreaks have been reported. Corynebacteriumspp. may be specimen or laboratory contaminants. CDC coryneform groups 1, E, F-1, and G-2 await designation of scientific names
  • C. glucuronolyticum
  • C. imitans
  • C. jeikeium
  • C. kroppenstedtii
  • C. kutscheri
  • C. lipophilum
  • C. macginleyi
  • C. matruchotii
  • C. mucifaciens
  • C. pilosum
  • C. propinquum
  • C. renale
  • C. resistens
  • C. riegelii
  • C. sanguinis
  • C. singulare
  • C. striatum
  • C. sundsvallense
  • C. thomssenii
  • C. tuberculostearicum
  • C. tuscaniense
  • C. urealyticum
  • C. xerosis
C. diphtheriae Diphtheria, cutaneous infection Penicillin, erythromycin Toxigenic infection requires treatment with antitoxin
C. minutissimum Erythrasma, bacteraemia, endocarditis   Role as an agent of erythrasma is poorly defined
C. mycetoides Tropical ulcer, septicaemia    
C. pseudodiphtheriticum UTI, endocarditis, lymphadenopathy, necrotizing tracheitis Penicillin  
C. pseudotuberculosis Lymphadenitis, pulmonary infection Penicillin, erythromycin Associated with sheep contact. May require drainage or excision
C. ulcerans Diphtheria-like disease, pharyngitis Penicillin, erythromycin Toxigenic infection requires treatment with antitoxin
C. vitaeruminis Associated with aortic aneurysm   Role as pathogen uncertain
[Corynebacterium group A-3—see Cellulomonas]
[Corynebacterium groups A-4 and A-5—see Microbacterium]
[Corynebacterium group 2—see Arcanobacterium bernardiae]
Coxiella C. burnetii Q fever Tetracycline, ciprofloxacin, co-trimoxazole, rifampicin  
Cryptobacterium C. curtum Periodontitis    
Cupriavidus (Ralstonia) (Wautersia)
  • C. gilardii
  • C. pauculus
  • C. respiraculi
  • C. taiwanensis
Meningitis, pulmonary infection in cystic fibrosis, line sepsis Cephalosporins, imipenem, co-trimoxazole, quinolones, amikacin  
Delftia D. acidovorans (Comamonas acidovorans) Bacteraemia, endocarditis Ureidopenicillins, fluoroquinolones  
Dermabacter D. hominis Brain abscess, bacteraemia, wound infection Cephalosporins, glycopeptides  
Dermacoccus D. sp. Associated with aortic aneurysm   Role as pathogen uncertain. Found on skin and mucous membranes
Dermatophilus D. congolensis Cutaneous infection Penicillin Zoonosis from cattle, sheep, goats, and horses
Desulfomicrobium D. orale Periodontitis    
Desulfomonas D. piger (D. pigra) Pilonidal cyst abscess, peritonitis   From faecal flora
  • D. desulfuricans
  • D. vulgaris
Bacteraemia, liver abscess Penicillin, clindamycin  
D. fairfieldensis Cultured from urine of patient with UTI and meningoencephalitis   Proposed name does not have standing in nomenclature
  • D. invisus
  • D. micraerophilus
  • D. pneumosintes
  • D. propionicifaciens
Periodontitis, endodontic infection, bacteraemia    
Dichelobacter D. nodosus (Bacteroides nodosus) Pilonidal cyst, rectal fistula, wound infection   Cause of ovine footrot. Isolates reported from humans may not be D. nodosus
Dietzia D. maris Prosthetic hip infection, bacteraemia Vancomycin, teicoplanin, rifampicin, amoxicillin, gentamicin, clindamycin, co-trimoxazole Papillomatosis has been associated with ‘Dietzia strain X’
Dolosicoccus D. paucivorans Bacteraemia Cephalosporins  
Dolosigranulum D. pigrum Spinal cord infection, eye infection   Significance as a pathogen poorly defined.
  • D. capnocytophagoides (CDC group DF-3)
  • D. gadei
  • D. mossii
Diarrhoea, bacteraemia, abscess Tetracycline, clindamycin, imipenem  
  • E. hoshinae
  • E. ictaluri
  • E. tarda
Wound infection, abscesses, gastroenteritis β-Lactams, aminoglycosides, fluoroquinolones Aquatic exposure, penetrating fish injury
  • E. hongkongensis
  • E. lenta (Eubacterium lentum)
  • E. sinensis
Rectal abscess, bacteraemia Penicillin, metronidazole Variable susceptibility to cefotaxime
  • E. chaffeensis
  • E. ewingii
Ehrlichiosis Tetracycline, doxycycline Antibodies to E. muris detected in healthy humans in Japan
[Ehrlichia sennetsu—see Neorickettsia sennetsu]
Eikenella E. corrodens Septicaemia, endocarditis, abscesses, septic arthritis Penicillin (plus gentamicin for endocarditis)  
Elizabethkingia E. meningoseptica (Chryseobacterium meningosepticum, Flavobacterium meningosepticum) Meningitis, bacteraemia, endocarditis, necrotizing fasciitis, pneumonia Quinolones, co-trimoxazole, minocycline, rifampicin Treatment with vancomycin is controversial
Empedobacter E. brevis (Flavobacterium breve) Endophthalmitis, bacteraemia, UTI Broad-spectrum cephalosporins Carbapenem-resistant
  • E. aerogenes
  • E. amnigenus
  • E. asburiae
  • E. cancerogenus
  • E. cloacae
  • E. gergoviae
  • E. hormaechei
  • E. kobei
  • E. ludwigii
  • E. sakazakii
Bacteraemia, respiratory tract infections, UTI Carbapenems, fluoroquinolones, aminoglycosides, ureidopenicillins May be multiresistant. Common cause of nosocomial infection
  • E. avium
  • E. casseliflavus (E. flavescens)
  • E. cecorum
  • E. dispar
  • E. durans
  • E. faecalis
  • E. faecium
  • E. gallinarum
  • E. gilvus
  • E. hirae
  • E. malodoratus
  • E. mundtii
  • E. pallens
  • E. pseudoavium
  • E. raffinosus
  • E. solitarius
Bacteraemia, abscesses, endocarditis, meningitis, UTI, peritonitis, osteomyelitis, wound infection Penicillins, glycopeptides May be resistant to penicillins and glycopeptides. Nosocomial outbreaks reported
Erwinia E. persicinus UTI Cephalosporins, fluoroquinolones, aminoglycosides The causative agent of necrosis of bean pods
Erysipelothrix E. rhusiopathiae Erysipeloid, septicaemia, endocarditis Penicillin Animal contact
[Escherichia adecarboxylata—see Leclercia adecarboxylata]
Escherichia E. albertii Diarrhoea   Previously known as Hafnia alvei-like strains
E. coli UTI, bacteraemia, wound infection, meningitis, enteric infection, haemolytic fluoroquinolones, uraemic syndrome β-Lactams, aminoglycosides, co-trimoxazole Susceptibilities variable
E. fergusonii Bacteraemia, wounds, UTI Chloramphenicol, gentamicin Ampicillin-resistant
E. hermanii Wounds Chloramphenicol, cephalosporins, gentamicin  
E. vulneris Wounds Ampicillin, cephalosporins, gentamicin  
  • E. brachy
  • E. combesii
  • E. contortum
  • E. cylindroids
  • E. infirmum
  • E. limosum
  • E. minutum
  • E. moniliforme
  • E. multiforme
  • E. nitrogenes
  • E. nodatum
  • E. plautii
  • E. rectale
  • E. saburreum
  • E. saphenum
  • E. sulci
  • E. tenue
  • E. timidum
  • E. tortuosum
  • E. ventriosum
  • E. yurii yurii
  • E. yurii mararetiae
  • E. yurii schtitka
Wounds, abscesses, septicaemia, periodontitis Penicillins, clindamycin, metronidazole  
Ewingella E. americana Septicaemia, wounds, UTI Ureidopenicillins, aminoglycosides  
  • E. acetylicum
  • E. aurantiacum
Wound infection, bacteraemia    
  • F. hominis
  • F. ignava
  • F. languida
  • F. sourekii
UTI, bacteraemia, abscess    
  • F. alocis
  • F. vilosus
Gingivitis, periodontitis    
Finegoldia F. magna (Peptostreptococcus) magnus      
[Flavimonas oryzihabitans—see Pseudomonas oryzihabitans]
Flavobacterium F. mizutaii (Sphingobacterium mizutae)      
[Flavobacterium gleum—see Chryseobacterium gleum]
[Flavobacterium indologenes—see Chryseobacterium indologenes]
[Flavobacterium meningosepticum—see Elizabethkingia meningoseptica]
Flexispira ‘F. rappini’ Bacteraemia, diarrhoea   Not in approved lists of bacterial names. There is a growing consensus that ‘Flexispira’ actually represents several Helicobacter spp.
[Fluoribacter bozemanae—see Legionella bozemanae]
[Fluoribacter dumoffii—see Legionella dumoffii]
[Fluoribacter gormanii—see Legionella gormanii]
Francisella F. philomiragia (Yersinia philomiragia) Septicaemia, invasive systemic infection Fluoroquinolones, aminoglycosides, chloramphenicol, cefoxitin  
F. tularensis Tularaemia Streptomycin, tetracycline  
  • F. gonidiaformans
  • F. mortiferum
  • F. naviforme
  • F. necrogenes
  • F. necrophorum necrophorum
  • F. necrophorum fundiliforme
  • F. nucleatum nucleatum
  • F. nucleatum fusiforme
  • F. nucleatum polymorphum
  • F. nucleatum vincentii
  • F. periodonticum
  • F. russii
  • F. ulcerans
  • F. varium
Abscesses, bacteraemia, periodontitis, endocarditis, necrobacillosis Metronidazole, penicillins, carbapenems, cephalosporins  
Gardnerella G. vaginalis Intrauterine and neonatal sepsis β-Lactams, clindamycin Associated with bacterial vaginosis
  • G. bergeri
  • G. haemolysins
  • G. morbillorum (Streptococcus morbillorum)
  • G. sanguinis
Bacteraemia, endocarditis Penicillin or vancomycin (plus gentamicin for endocarditis)  
Globicatella G. sanguinis Bacteraemia, UTI, meningitis Vancomycin  
Gordonia (Gordona) (Rhodococcus)
  • G. aichensis
  • G. araii
  • G. bronchialis
  • G. effuse
  • G. otitidis
  • G. polyisoprenivorans
  • G. rubropertinctus
  • G. sputi
  • G. terrae
Pulmonary infection, cholecystitis, breast abscess, sternal wound sepsis, brain abscess, bacteraemia, otitis Co-trimoxazole, ceftriaxone, imipenem, fluoroquinolones  
Granulicatella G. adiacens (Abiotrophia adiacens) G. elegans (Abiotrophia elegans) Endocarditis, septic arthritis, endodontic infection Penicillin or cefazolin or vancomycin plus gentamicin (plus rifampicin) Previously known as nutritionally deficient or variant streptococci; the proposed name ‘Abiotrophia para-adiacens’ for strains allied to what is now known as Granulicatella adiacens does not have standing in nomenclature
Grimontia G. hollisae (Vibrio hollisae) Diarrhoea β-Lactams, quinolones Infection associated with ingestion of shellfish
Haemophilus H. aegyptius Brazilian purpuric fever Ampicillin, cephalosporins, chloramphenicol Treated by some authors as a biotype of H. influenzae
  • H. aphrophilus (H. paraphrophilus)
  • H. parainfluenzae
  • H. pittmaniae
  • H. segnis
Sinusitis, otitis media, pneumonia, abscesses, endocarditis Cefotaxime, chloramphenicol, ampicillin, aminoglycosides The genus Aggregatibacter has been proposed to accommodate H. aphrophilus (including H. paraphrophilus as a heterotypic synonym of H. aphrophilus), H. signis, and Actinobacillus actinomycetemcomitans
H. ducreyi Chancroid Macrolides, ceftriaxone, fluoroquinolones  
H. influenzae Bacteraemia, meningitis, epiglottitis Cephalosporins, penicillins, fluoroquinolones Many strains produce penicillinases
Hafnia H. alvei Bacteraemia   Doubtful enteropathogen. Susceptibility variable. Includes two genomospecies. ‘Hafnia alvei-like’ strains from Bangladesh have been described as Escherichia albertii
  • H. kunzii
  • ‘H. pyogenica’
  • H. sueciensis
Sebaceous cyst infection, breast abscess, wound infection Penicillins, vancomycin From skin flora. The name H. pyogenica does not have standing in nomenclature
Helicobacter H. bilis (‘Flexispira rapinni’ corrig. taxon 9) Cholecystitis, bacteraemia   Zoonosis from rodents
H. canis Gastroenteritis   Zoonosis from dogs
H. cinaedi (Campylobacter cinaedi) H. fennelliae (Campylobacter fennelliae) Proctitis in homosexual men, septicaemia Ampicillin, gentamicin Zoonoses from hamsters
  • H. bizzozeronii
  • H. felis
  • H. salomonis
  • ‘Candidatus H. bovis
  • ‘Candidatus H. heilmannii’
  • (‘Gastrospirillum hominis’)
  • ‘Candidatus H. suis
  • (‘H. heilmannii-like organisms’)
Gastritis   Zoonoses from domestic and farm animals. Some organisms known as ‘Flexipsira rapini’ may belong to this group of Helicobacter spp.
  • H. canadensis
  • H. pullorum
Gastroenteritis   Zoonoses from birds (or possibly rodents)
H. pylori (Campylobacter pyloridis) Gastritis Omeprazole plus clarithromycin and metronidazole Numerous similar treatment combinations have been recommended
H. westmeadii Bacteraemia in AIDS   Name does not have standing in nomenclature
H. winghamensis Gastroenteritis   Name does not have standing in nomenclature. Possibly a zoonosis from rodents
Herbaspirillum H. sp. Associated with aortic aneurism   Detected by 16S gene analysis. Of doubtful clinical significance
Holdemania H. filiformis     From faecal flora. Clinical significance is unclear
Ignavigranum I. ruoffiae Wound infection, ear abscess   Role as pathogen poorly defined
Inquilinus I. limosusI. sp. Pulmonary infection in cystic fibrosis, endocarditis Imipenem, quinolones, gentamicin  
Janibacter J. melonis Bacteraemia Vancomycin, β-lactams, fluoroquinolones An undescribed Janibacter sp. was isolated from a leukaemia patient
Johnsonella J. ignava Periodontitis    
Kerstersia K. gyiorum Wound infection    
  • K. denitrificans
  • K. kingae
  • K. oralis
  • K. potus
Septic arthritis, endocarditis, bite infection Penicillins (plus gentamicin for endocarditis)  
[Kingella indologenes—see Suttonella indologenes]
Klebsiella K. granulomatis (Calymmatobacterium granulomatis) Donovanosis Tetracycline, co-trimoxazole  
[Klebsiella ornitholytica, K. planticola, K. terrigena—see Raoultella]
  • K. oxytoca
  • K.pneumoniae ssp. pneumoniae
  • K. pneumoniae ssp. ozaenae
  • K. variicola
UTI, bacteraemia, wound infection, respiratory tract infection β-Lactams, aminoglycosides, fluoroquinolones Susceptibilities vary. Nosocomial outbreaks reported
K. pneumoniae ssp. rhinoscleromatis Rhinoscleroma Ciprofloxacin, rifampicin, co-trimoxazole  
  • K. ascorbate
  • K. cryocrescens
  • K. georgiana
  • K. intermedia (Enterobacter intermedius)
Bacteraemia, UTI, mediastinitis, line sepsis Aminoglycosides, ceftazidime, imipenem, ciprofloxacin  
Kocuria (Micrococcus)
  • K. kristinae
  • K. rosea
  • K. varians
Cholecystitis, line-related sepsis Penicillin, clindamycin, vancomycin  
[Koserella trabulsii—see Yokenella regensburgei]
Kurthia ‘K. bessonii’ Bacteraemia, endocarditis Penicillin Not in approved lists of bacterial names
  • K. gibsonii
  • K. zopfii
    Isolated from faeces of patients with diarrhoea
Kytococcus (Micrococcus)
  • K schroeteri
  • K. sedentarius
Endocarditis, cerebral cyst infection Imipenem, vancomycin, rifampicin  
  • L. acidophilus
  • L. brevis
  • L. casei
  • L. catenaformis
  • L. coleohominis
  • L. crispatus
  • L. fermentum
  • L. gasseri
  • L. iners
  • L. jensenii
  • L. leichmannii
  • L. oris
  • L. paracasei
  • L. paraplantarum
  • L. plantarum
  • L. rhamnosus
  • L. salivarius
  • L. vaginalis
Abscesses, bacteraemia, endometritis, endocarditis, lung infection, UTI Cephalosporins, vancomycin, penicillins, aminoglycosides, clindamycin Reported risk factors for infection include surgery, malignancy, diabetes, and immunodeficiency. May be vancomycin-resistant
Lactococcus (Streptococcus)
  • L. garviae
  • L. lactis
Bacteraemia, endocarditis, UTI Penicillin (plus gentamicin for endocarditis)  
Lautropia L. mirabilis     Role as potential pathogen unclear. From oral flora of HIV patients and sputum of cystic fibrosis patient
Leclercia L. adecarboxylata (Escherichia adecarboxylata) Bacteraemia, wound infection   Variable susceptibility
  • L. anisa
  • L. birminghamensis
  • L. bozemanae (L. bozemanii)
  • L. cincinnatiensis
  • L. dumoffii
  • L. feeleii
  • L. gormanii
  • L. hackeliae
  • L. israelensis
  • L. jordanis
  • L. lansingensis
  • L. longbeachae
  • L. lytica
  • L. maceachernii
  • L. micdadei
  • L. oakridgemsis
  • L. pneumophila
  • L. quinlivanii
  • L. rubrilucens
  • L. sainthelensi
  • L. tucsonensis
  • L. wadsworthia
  • L. worsleiensis
Legionnaires’ disease, Pontiac fever Macrolides, fluoroquinolones, rifampicin Infections caused by species other thanL. pneumophila and L. micdadei are seldom reported
Leifsonia L. aquatica (Corynebacterium aquaticum) UTI, endocarditis, meningitis, CAPD peritonitis Ampicillin, chloramphenicol, gentamicin Previously confused with Aureobacterium (which has been united with Microbacterium)
  • L. grimontii
  • L. richardii
UTI, bacteraemia, surgical site infection, peritonitis Imipenem, chloramphenicol, tetracycline, gentamicin  
  • L. biflexa
  • L. borgpetersenii
  • L. broomii
  • L. inadai
  • L. interrogans
  • L. kirschneri
  • L. noguchii
  • L. santarosai
  • L. weilii
Leptospirosis Penicillin, tetracycline L. interrogans is composed of severalnamed serogroups, including: australis, bataviae, canicola, copenhageni, cynopteri, hurstbridge, hardjo, grippotyphosa, icterohaemorrhagiae, panama, pomona, pyrogenes, sejroe, tarassovi
  • L. buccalis
  • L. goodfellowii
  • L. shahii
  • L. trevisanii
Bacteraemia, endocarditis β-Lactams, metronidazole Associated with dental plaque and gingivitis. ‘L. amnionii’ from amniotic fluid does not have standing in nomenclature and may belong in the genus Sneathia
  • L. citreum
  • L. lactis
  • L. mesenteroides ssp. cremoris
  • L. mesenteroides ssp. dextranicum
  • L. mesenteroides ssp. mesenteroide
  • L. pseudomesenteroides
Meningitis, bacteraemia, pulmonary infection Penicillin and gentamicin or clindamycin Vancomycin-resistant
  • L. ivanovii
  • L. grayi
  • L. monocytogenes
  • L. seeligeri
Septicaemia, meningitis, intrauterine infection, enteric infection Ampicillin and gentamicin  
[Listonella damsela—see Photobacterium damselae]    
  • L. peritonei
  • L. sanguinis
Peritonitis, bacteraemia    
Massilia M. timonae Bacteraemia, wound infection    
  • M. elsdenii
  • M. micronuciformis
Endocarditis, abscess Metronidazole  
Mesorhizobium M. amorphae Pneumonia    
  • M. extorquens
  • M. mesophilicum (Pseudomonas mesophilica)
Bacteraemia, CAPD peritonitis, UTI, septic arthritis Ureidopenicillins, imipenem, aminoglycosides, chloramphenicol, fluoroquinolones Detected in aortic aneurysm
Microbacterium (Aureobacterium)
  • M. arborescens
  • M. imperiale (CDC coryneform groups A-4 and A-5)
  • M. liquefaciens (Aureobacterium liquefaciens)
  • (‘Corynebacterium aquaticum’)
  • M. oxydans
  • M. paraoxydans
  • M. resistens
  • M. trichothecenolyticum
Endophthalmitis, UTI, endocarditis, soft tissue infection, hypersensitivity pneumonitis, meningitis, CAPD peritonitis, bacteraemia Glycopeptides, β-lactams, chloramphenicol, gentamicin M. resistens is vancomycin-resistant. Microbacterium isolates have been misidentified as ‘Corynebacterium aquaticum’ a taxon now known as Leifsonia aquatica
  • M. luteus
  • M. lytae
Bacteraemia, endocarditis, septic arthritis Vancomycin, penicillin, rifampicin From skin flora. Common specimen contaminants
Mitsuokella M. multocida (Bacteroides multiacidus)     Role as human pathogen poorly defined
Nomenclature Associated infections Reported susceptibilities and treatments Notes
Genus Species and subspecies
(synonyms, CDC alphanumeric groups)
  • M. curtisii curtisii
  • M. curtisii holmesii
  • M. mulieris
Endometritis, chorioamnionitis Ampicillin, cephalosporins, clindamycin Associated with bacterial vaginosis
Moellerella M. wisconsensis Diarrhoea   Of uncertain significance
  • M. diversum
  • M. neglectum
Endodontic infection    
  • M. atlantae
  • M. catarrhalis (Branhamella catarrhalis)
  • M. lacunata
  • M. nonliquefaciens
  • M. osloensis
Conjunctivitis, wound infection, endocarditis, abscesses, osteomyelitis, respiratory infections, endocarditis, bacteraemia Penicillin, cefuroxime Penicillin resistance has been reported. Some authors retain Branhamella catarrhalis
[Moraxella phenylpyruvica—see Psychrobacter phenylpyruvicus]
[Moraxella urethralis—see Oligella urethralis]
  • M. morganii morganii
  • M. morganii sibonii
Bacteraemia, UTI, wound infection β-Lactams, aminoglycosides Susceptibilities vary
Moryella M. indoligenes      
  • M. abscessus
  • M. africanum
  • M. alvei
  • M. asiaticum
  • M. arupense
  • M. aubagnense
  • M. aurum
  • M. avium
  • M. barrassiae
  • M. boenickei
  • M. bohemicum
  • M. bolletii
  • M. bovis
  • M. branderi
  • M. brisbanense
  • M. brumae
  • M. canariasense
  • M. celatum
  • M. chelonae
  • M. chimaera
  • M. chubuense
  • M. colombiense
  • M. conceptionense
  • M. confluentis
  • M. conspicuum
  • M. cookii
  • M. cosmeticum
  • M. doricum
  • M. elephantis
  • M. flavescens
  • M. florentinum
  • M. fortuitum
  • M. gadium
  • M. gastri
  • M. genavense
  • M. goodii
  • M. gordonae
  • M. haemophilum
  • M. hassiacum
  • M. heckeshornense
  • M. heidelbergense
  • M. hodleri
  • M. holsaticum
  • M. houstonense
  • M. immunogenum
  • M. interjectum
  • M. intracellulare
  • M. jacuzzii
  • M. kansasii
  • M. kubicae
  • M. kumamotonense
  • M. lacus
  • M. lentiflavum
  • M. leprae
  • M. mageritense
  • M. malmoense
  • M. marinum
  • M. massiliense
  • M. microgenicum
  • M. microti
  • M. monacense
  • M. mucogenicum
  • M. neoaurum
  • M. nebraskense
  • M. neworleansense
  • M. nonchromogenicum
  • M. novocastrense
  • M. palustre
  • M. parascrofulaceum
  • M. parmense
  • M. peregrinum
  • M. p hlei
  • M. phocaicum
  • M. porcinum
  Isoniazid, rifampicin, ethambutol, pyrazinamide, streptomycin, azithromycin, clarithromycin, ciprofloxacin, dapsone, clofazimine, imipenem, co-trimoxazole, amikacin Many Mycobacterium spp. have been associated with infection. M. tuberculosis, M. africanum, and M. bovis are the agents of tuberculosis. M. scrofulaceum causes cervical adenitis. The agent of Buruli ulcer is M. ulcerans. M. marinum causes fish-tank granuloma. M. lepraecauses leprosy. M. malmoense, M. szulgai, M. shimoidei, M. kansasii, and M. xenopi cause pulmonary infection. M. intracellulareand M. avium cause systemic infection mainly in immunocompromised patients. The rapid growers, M. chelonae,M. abscessus, and M. fortuitum cause local postinoculation injury and systemic infection
  • M. saskatchewanense
  • M. scrofulaceum
  • M. seoulense
  • M. septicum
  • M. shimoidei
  • M. simiae
  • M. smegmatis
  • M. szulgai
  • M. terrae
  • M. thermoresistibile
  • M. triplex
  • M. triviale
  • M. tuberculosis
  • M. tusciae
  • M. ulcerans
  • M. vaccae
  • M. wolinskyi
  • M. xenopi
  • M. amphoriforme
  • M. buccale
  • M. faucium
  • M. fermentans
  • M. genitalium
  • M. hominis
  • M. lipophilum
  • M. orale
  • M. penetrans
  • M. pirum
  • M. pneumoniae
  • M. primatum
  • M. salivarium
  • M. spermatophilum
Respiratory infection, postpartum fever, pyelonephritis, pelvic inflammatory disease, myocarditis, pericarditis, meningitis Tetracycline, macrolides, fluoroquinolones May be resistant to macrolides. M. pneumoniaeinfection may be complicated by haemolytic anaemia, intravascular coagulation, Stevens–Johnson syndrome, or erythema multiforme
M. phocicerebrale (M. phocacerebrale) Seal finger Tetracycline Other Mycoplasma spp. from seals are M. phocae and M. phocirhinis
Myroides (Flavobacterium)
  • M. odoratimimus
  • M. odoratus
UTI, wound infection Minocycline May be multiresistant
  • N. animaloris
  • (CDC gro up EF-4a)
  • N. canis
  • N. weaveri
  • (CDC group M-5, ‘Neisseria parelongata’)
  • N. zoodegmatis
  • (CDC group EF-4b)
Wound infections, abscesses, endocarditis, meningitis, bacteraemia Amoxicillin Zoonoses from animal bites
  • N. bacilliformis
  • N. cinerea
  • N. elongata elongata
  • N. elongata glycolytica
  • N. elongata nitroreductens
  • N. flavescens
  • N. lactamica
  • N. mucosa
  • N. polysaccharea
  • N. sicca
  • N. subflava
Meningitis, bacteraemia, endocarditis, osteomyelitis Penicillin, cephalosporins Bacteraemia in AIDS reported for several species. Penicillin resistance rarely reported in commensal Neisseriaspp. N. subflava includes biovars flava, perflava, and subflava
N. gonorrhoeae Gonorrhoea, septicaemia, ophthalmia neonatorum Cephalosporins Susceptibility varies geographically. The name ‘Neisseria gonorrhoeae ssp. kochii’ was proposed for isolates from conjunctivitis cases in rural Egypt
N. meningitidis Septicaemia, meningitis, conjunctivitis, genital infection, epiglottitis Penicillin, cefotaxime Rifampicin, ciprofloxacin, or ceftriaxone to clear carriage
Neorickettsia N. sennetsu (Ehalichia sennetsu) Sennetsu fever Doxycycline Associated with eating raw fish in Asia
  • N abscessus
  • N. africana
  • N. anaemiae
  • N. aobensis
  • N. araoensis
  • N. arthritides
  • N. asiatica
  • N. asteroides
  • N. beijingensis
  • N. brasiliensis
  • N. brevicatena
  • N. carnea
  • N. concave
  • N. cyriacigeorgica
  • N. elegans
  • N. exalbida
  • N. farcinica
  • N. higoensis
  • N. inohanensis
  • N. kruczakiae
  • N. mexicana
  • N. niigatensis
  • N. ninae
  • N. nova
  • N. otitidiscaviarum
Nocardiosis (including bacteraemia, pulmonary and soft tissue infections) Sulphonamides, co-trimoxazole, amikacin, imipenem  
  • N. paucivorans
  • N. pneumoniae
  • N. pseudobrasiliensis
  • N. puris
  • N. sienata
  • N. takedensis
  • N. thailandensis
  • N. testaceus
  • N. transvalensis
  • N. vermiculata
  • N. veterana
  • N. yamanashiensis
  • N. dassonvillei
  • N. synnemataformans
Mycetoma, cutaneous infection, pulmonary infection, conjunctivitis Fluoroquinolones, piperacillin  
Ochrobactrum (Achromobacter CDC group Vd; Achromobacter groups A, C, and D)
  • O. anthropi
  • O. intermedium
Bacteraemia, endophthalmitis, liver abscess Imipenem, fluoroquinolones, aminoglycosides Nosocomial infections in debilitated patients
Oerskovia O. turbata (Cellulomonas turbata) Bacteraemia, endocarditis Amikacin, co-trimoxazole, chloramphenicol Vancomycin resistance reported
Oligella O. ureolytica (CDC IVe) O. urethralis (Moraxella urethralis) UTI, septicaemia Aminoglycosides, cephalosporins Associated with urinary catheters
Olsenella O. uli (Lactobacillus uli)      
Orientia O. tsutsugamushi (Rickettsia tsutsugamushi) Scrub typhus Tetracycline, chloramphenicol  
  • P. alvei
  • P. macerans
  • P. polymyxa
  • P. popilliae
Septicaemia, meningitis, pneumonia Vancomycin  
Pannonibacter P. phragmitetus (Achromobacter groups B and E)      
  • P. agglomerans (Enterobacter agglomerans)
  • P. ananatis
  • P. dispersa
Bacteraemia, endocarditis, wound infection, cellulitis, alligator-bite infection, endophthalmitis Carbapenems, fluoroquinolones, ureidopenicillins, aminoglycosides Susceptibilities vary. May be multiresistant
  • P. distasonis
  • P. goldsteinii (Bacteroides goldsteinii)
  • P. merdae
Abscesses Metronidazole  
Parachlamydia P. acanthamoebae Humidifier fever    
Paracoccus P. yeei Bacteraemia Ampicillin, cephalosporins, ciprofloxacin  
Parvimonas P. micra (Peptostreptococcus micros)      
  • P. aerogenes
  • P. bettyae
  • P. canis
  • P. dagmatis
  • P. gallinarum
  • P. haemolytica
  • P. multocida multocida
  • P. multocida gallicida
  • P. multocida septica
  • P. pneumotropica
  • P. stomatis
Wound infection, septicaemia, abscesses, pneumonia, endocarditis, meningitis Penicillin, tetracycline, ciprofloxacin Pasteurella infections in humans relate to species usually associated with animals. There may be no history of an animal bite or contact
[Pasteurella ureae—see Actinobacillus ureae]
  • P. acidilactici
  • P. damnosus
  • P. dextrinicus
  • P. parvulus
  • P. pentosaceus
Bacteraemia, abscesses, pulmonary infection Imipenem, gentamicin, chloramphenicol Debilitated hospital patients. Resistant to vancomycin
Peptococcus P. niger Abdominal sepsis Penicillin, clindamycin  
Peptoniphilus (Peptostreptococcus)
  • P. asaccharolyticus
  • P harei
  • P. indolyticus
  • P. ivorii
  • P. lacrimalis
Mixed anaerobic infections, abscesses β-Lactams, metronidazole, chloramphenicol  
  • P. anaerobius
  • P. stomatis
  • ‘P. trisimilis’
Mixed anaerobic infections, abscesses, endocarditis β-Lactams, metronidazole, chloramphenicol See also Peptoniphilus, Anaerococcus, Finegoldia
Photobacterium P. damselae (Listonella damsela and Vibrio damsela) Necrotizing wound infection, bacteraemia Penicillins, tetracycline, chloramphenicol Infection associated with penetrating fish injury. May require debridement
Photorhabdus (Xenorhabdus) P. luminescens Bacteraemia, wound infection Cefoxitin, oxacillin, gentamicin  
Plesiomonas P. shigelloides Gastroenteritis, septicaemia, meningitis, endophthalmitis Ciprofloxacin, trimethoprim, cephalosporins Infections associated with contaminated food and water
Porphyromonas (Bacteroides)
  • P. asaccharolytica
  • P. cangingivalis
  • P. canoris
  • P. cansulci
  • P. catoniae
  • P. circumdentaria
  • P. crevioricanis
  • P. endodontalis
Mixed anaerobic infections at various sites, periodontitis, human and animal bites Metronidazole, ureidopenicillins, amoxicillin/clavulanate, carbapenems, cephalosporins, chloramphenicol Members of the oral flora of humans and animals
  • P. gingivalis
  • P. gingivicanis
  • P. levii
  • P. macacae
  • P. somerae
  • P. uenonis
Prevotella (Bacteroides)
  • P. bergensis
  • P. bivia
  • P. buccae
  • P. buccalis
  • P. corporis
  • P. dentalis
  • P. denticola
  • P. disiens
  • P. enoeca
  • P. heparinolytica
  • P. intermedia
  • P. loeschii
  • P. melaninogenica
  • P. multiformis
  • P. multisaccharivorax
  • P. nigrescens
  • P. oralis
  • P. oris
  • P. oulorum
  • P. tannerae
  • P. timonensis
  • P. veroralis
  • P. zoogleoformans
Abscesses, bacteraemia, wound infection, bite infections, genital tract infections, periodontitis, endodontic infection Metronidazole, amoxicillin/clavulanate, ureidopenicillins, carbapenems, cephalosporins, clindamycin, chloramphenicol A genus that includes the well-known former Bacteroides melaninogenicusand allied species of anaerobes
  • P. acnes
  • P. avidum
  • P. granulosum
  • P. propionicum (Arachnia propionicus)
Abscesses, endocarditis, bacteraemia, septic arthritis, endophthalmitis Glycopeptides, penicillin, macrolides Associated with acne vulgaris
Propionimicrobium P. lymphophilum (Propionibacterium lymphophilum) UTI   Isolated from lymph nodes in Hodgkin’s disease
  • P. mirabilis
  • P. penneri
  • P. vulgaris
UTI, bacteraemia, wound infection, abscesses β-Lactams, aminoglycosides, fluoroquinolones Susceptibilities vary
  • P. alcalifaciens
  • P. rettgeri
  • P. rustigianii
  • P. stuartii
UTI, wound infection, bacteraemia β-Lactams, aminoglycosides, fluoroquinolones Susceptibilities vary. P. alcalifaciens has been associated with gastroenteritis
[Pseudomonas acidivorans—see Delftia acidivorans]
  • P. aeruginosa
  • P. alcaligenes
  • P. chlororaphis
  • P. fluorescens
  • P. mendocina
  • P. monteilii
  • P. mosselii
  • P. otitidis
  • P. pertocinogena
  • P. pseudalcaligenes
  • P. putida
  • P. stutzeri
Bacteraemia, UTI, wound infection, abscesses, septic arthritis, conjunctivitis, endocarditis, meningitis, otitis Ureidopenicillins, aminoglycosides, ceftazidime, fluoroquinolones, carbapenems Nosocomial infections associated with invasive devices in debilitated patients. Nosocomial outbreaks reported. May be multiresistant
[Pseudomonas cepacia—see Burkholderia cepacia]
[Pseudomonas diminuta—see Brevundimonas diminuta]
[Pseudomonas mallei—see Burkholderia mallei]
[Pseudomonas maltophilia—see Stenotrophomonas maltophilia]
[Pseudomonas mesophilica—see Methylobacterium mesophilicum]
  P. luteola (Chryseomonas luteola) Bacteraemia, endocarditis, CAPD peritonitis Ureidopenicillins, ceftazidime, ciprofloxacin, aminoglycosides  
P. oryzihabitans (Flavimonas oryzihabitans) Septicaemia, eye infection, CAPD peritonitis Ampicillin, tetracycline, gentamicin, cefotaxime  
[Pseudomonas paucimobilis—see Sphingomonas paucimobilis]
[Pseudomonas pickettii—see Ralstonia pickettii]
[Pseudomonas pseudomallei—see Burkholderia pseudomallei]
[Pseudomonas putrefaciens—see Shewanella putrefaciens]
[Pseudomonas terrigena—see Comamonas terrigena]
[Pseudomonas testosteroni—see Comamonas testosteroni]
[Pseudomonas vesicularis—see Brevundimonas vesicularis]
Pseudonocardia P. autotrophica (Amycolata autotrophica)     Role as pathogen uncertain
Pseudoramibacter P. alactolyticus Periodontal disease, wound infection, abscesses Penicillin, clindamycin, chloramphenicol  
  • P. immobilis
  • P. phenylpyruvicus (Moraxella phenylpyruvica)
Meningitis, bacteraemia, eye infection Penicillins, aminoglycosides, chloramphenicol  
Rahnella R. aquatilis UTI, septicaemia Ciprofloxacin Immunocompromised patients
  • R. insidiosa
  • R. mannitolilytica
  • R. pickettii (Pseudomonas pickettii)
  • R. taiwanensis
Meningitis, peritonitis, bacteraemia, UTI, pulmonary infection Co-trimoxazole, imipenem, ceftazidime, quinolones  
Raoultella (Klebsiella)
  • R. ornithinolytica
  • R. planticola
  • R. terrigena
Bacteraemia, UTI, surgical sepsis, pancreatitis Cephalosporins, carbapenems, aztreonam, quinolones, aminoglycosides β-Lactamase producers. Associated with histamine (scombrotoxin) fish poisoning
Rasbo R. bacterium Pneumonia, pericarditis   Proposed name does not have standing in nomenclature
Rhodococcus R. equi (Corynebacterium equi) Bacteraemia, osteomyelitis, lung abscesses Vancomycin, erythromycin, aminoglycosides In immunocompromised patients, including AIDS
  • R. africae
  • R. akari
  • R. australis
  • R. conorii
  • R. felis
  • R. honei
  • R. japonica
  • ‘R. mongolotimonae’
  • R. prowazekii
  • R. rickettsiae
  • R. sibirica
  • R. slovaca
  • R. typhi
Rickettsial spotted fever, tick typhus, tick-bite fever, rickettsialpox Tetracycline Transmitted by arthropods. Agents of Astrakhan fever, Israeli tick typhus, and Thai tick typhus await designation of scientific names. Other Rickettsia spp. are of uncertain clinical significance
  • R. cervicalis
  • R. gilardii ssp.
  • gilardii
  • R. gilardi ssp.
  • rosea
  • R. mucosa
Bacteraemia, wound infection, peritonitis Aminoglycosides, imipenem, ciprofloxacin, ticarcillin-clavulanate  
[Roseomonas fauriae—see Azospirillum brasilense]
Rothia R. dentocariosa Endocarditis, abscesses Penicillin and gentamicin  
R. mucilaginosa (Micrococcus mucilaginosus) (Stomatococcus mucilaginosus) Endocarditis, meningitis, neutropenic sepsis, necrotizing fasciitis Glycopeptides, imipenem, rifampicin, ceftriaxone  
  • R. flavefaciens
  • R. hansenii (Streptococcus hansenii)
  • R. luti
  • R. productus (Peptostreptococcus productus)
Abdominal sepsis, abscesses Penicillins  
  • S. bongori
  • S. choleraesuis ssp. arizonae
  • S. choleraesuis ssp. choleraesuis
  • S. choleraesuis ssp. diarizonae
  • S. choleraesuis ssp. houtenae
  • S. choleraesuis ssp. indica
  • S. choleraesuis ssp. salamae
  • S. enteritidis
  • S. paratyphi
  • S. subterranea
  • S. typhi
  • S. typhimurium
  • S. enterica ssp. arizonae
  • S. enterica ssp. diarizonae
  • S. enterica ssp. enterica
  • S. enterica ssp. houtenae
  • S. enterica ssp. indica
  • S. enterica ssp. salamae
  • S. subterranea
Gastroenteritis, enteric fever, osteomyelitis β-Lactams, fluoroquinolones, chloramphenicol Salmonella nomenclature is complicated by the existence of two sets of names, both of which have standing in nomenclature. Both sets of names are listed in the table. The first scheme listed is more helpful for clinicians because it treats the clinically important taxa S. typhi (the agent of typhoid fever), S. paratyphi, S. enteritidis, and S. typhimurium as species. As yet, S. subterranea has not been associated with infection. It should be noted that bacteriologists widely adhere to the practice of writing serotype names in the form of Linnaean binomials (e.g. ‘S. virchow’) and that such names do not have standing in nomenclature
Scardovia S. inopinata (Bifidobacterium inopinatum) Dental caries    
  • S. artemidis
  • S. dianae
  • S. flueggei
  • S. infelix
  • S. noxia
  • S. sputigena
Bacteraemia, lung abscess Clindamycin, chloramphenicol, metronidazole Malignancy and alcohol abuse reported as risk factors for infection
[Serpulina—see Brachyspira]
  • S. ficaria
  • S. fonticola
  • S. grimesii
  • S. liquefaciens
  • S. marcescens
  • S. odorifera
  • S. plymuthica
  • S. proteamaculans
  • S. quinivorans
  • S. rubidaea
Septicaemia, abscesses, burn infections, osteomyelitis Imipenem, aminoglycosides, fluoroquinolones, ureidopenicillins, ceftazidime Nosocomial outbreaks reported. May be multiresistant. At time of writing a proposal to use the name S. rubidae in place of S. rubidaea has not been validly published
  • S. algae
  • S. putrefaciens (Alteromonas putrefaciens) (Pseudomonas putrefaciens)
Abdominal sepsis, meningitis, bacteraemia Ampicillin, cefotaxime, gentamicin, chloramphenicol Debilitated patients
  • S. boydii
  • S. dysenteriae
  • S. flexneri
  • S. sonnei
Enteric infection Co-trimoxazole, fluoroquinolones  
Simkania S. negevensis Bronchiolitis, pneumonia    
Slackia S. exigua (Eubacterium exiguum) Periodontitis    
Sneathia S. sanguinegens (Leptotrichia sanguinegens = L. microbii)      
Sphingobacterium (Flavobacterium)
  • S. multivorum
  • S. spiritivorum
  • S. thalpophilum
Bacteraemia, pulmonary infection Co-trimoxazole, chloramphenicol, tetracycline, cephalosporins, quinolones  
[Sphingobacterium mizutae—see Flavobacterium mizutaii]
  • S. parapaucimobilis
  • S. paucimobilis (Pseudomonas paucimobilis)
  • S. sanguinis (S. sanguis)
  • S. yanoikuyae
Septicaemia, UTI, wound infections, CAPD peritonitis Ceftazidime, aminoglycosides Nosocomial infections
Spirillum ‘S. minus’ Rat-bite fever Penicillin Streptobacillus moniliformis is also a rat-bite fever agent. The name ‘Spirillum minus’ does not have standing in nomenclature
  • S. aureus
  • S. auricularis
  • S. capitis capitis
  • S. capitis ureolyticus
  • S. caprae
  • S. cohnii cohnii
  • S. cohnii urealyticus
  • S. delphini
  • S. epidermidis
  • S. equorum
  • S. gallinarum
Bacteraemia, wound infection, endocarditis, catheter-related sepsis, UTI, toxic shock syndrome, food poisoning, eye infection, osteomyelitis Glycopeptides, β-lactams, aminoglycosides, tetracycline, macrolides, rifampicin, fluoroquinolones, daptomycin, linezolid, fusidic acid, mupirocin Staphylococci are surface commensals of humans and animals. S. aureus is also a major pathogen, causing focal and systemic sepsis, toxic shock syndrome, and food poisoning. S. epidermidis infection is often associated with foreign bodies (e.g. catheters and implants). S. saprophyticus causes UTI. S. lugdunensis is a rare cause of endocarditis. S. intermedius, S. hyicus, and others are from animals. Susceptibilities are variable but glycopeptide resistance is as yet rare
  • S. haemolyticus
  • S. hominis hominis
  • S. hominis novobiosepticius
  • S. hyicus
  • S. intermedius
  • S. lugdunensis
  • S. pasteuri
  • S. saccharolyticus
  • S. saprophyticus
  • S. schleiferi schleiferi
  • S. schleiferi coagulans
  • S. sciuri
  • S. simulans
  • S. vitulinus (S. pulvereri)
  • S. warneri
  • S. xylosus
  • S. maltophilia
  • (Pseudomonas maltophila)
  • (Xanthomonas maltophila)
  • (Stenotrophomonas africana)
Bacteraemia, meningitis, wound infection, UTI, pneumonia Fluoroquinolones, chloramphenicol, co-trimoxazole Resistance to aminoglycosides, penicillins, and carbapenems reported
[Stomatococcus mucilaginosus—see Rothia mucilaginosa]
Streptobacillus S. moniliformis Rat-bite fever, Haverhill fever Penicillin, erythromycin ‘Spirillum minus’ is also a causative agent of rat-bite fever
Streptococcus S. acidominimus Pneumonia, pericarditis, meningitis β-Lactams From cattle
  • S. agalactiae
  • S. canis
  • S. dysgalactiae dysgalactiae
  • S. dysgalactiae equisimilis
  • S. equi equi
  • S. equi zooepidemicus
  • S. iniae (S. shiloi)
  • S. porcinus
  • S. pseudoporcinus
  • S. pyogenes
  • S. urinalis
Pharyngitis, bacteraemia, pyogenic infection, necrotizing infection, septic arthritis, UTI, glomerulonephritis, meningitis β-Lactams, macrolides S. pyogenes (Lancefield group A), S. agalactiae (group B), and S. dysgalactiae equisimilis (groups C and G) are commensals and pathogens of humans. S. iniae is from fish. Others are from mammals
  • S. anginosus
  • S. constellatus constellatus
  • S. constellatus pharyngis
  • S. intermedius
Abscesses, bacteraemia, endocarditis, pharyngitis β-Lactams, macrolides Often termed ‘S. milleri’ or microaerophilic streptococci. From human oral flora
  • S. equinus (S. bovis)
  • S. gallolyticus ssp. gallolyticus
  • S. gallolyticus ssp. pateurianus
  • S. infantarius ssp. coli
  • S. infantarius ssp. infantarius
  • S. lutetiensis
  • S. pasteurianus
Endocarditis, CAPD peritonitis β-Lactams (plus gentamicin for endocarditis) Intestinal streptococci from animals and humans. Some taxonomic problems relating to this group (the ‘bovis’ streptococci) await resolution
  • S. criceti
  • S. mutans
  • S. ratti
  • S. sobrinus
Dental caries, endocarditis β-Lactams From the tooth-surface flora of humans and mammals
  • S. cristatus
  • S. gordonii
  • S. massiliensis
  • S. mitis
  • S. oralis
  • S. parasanguinis
  • S. salivarius
  • S. sanguinis
  • S. sinensis
  • S. vestibularis
Bacteraemia, endocarditis, wound infection β-Lactams, macrolides Human oral streptococci including taxa sometimes known as the ‘viridans streptococci’
  • S. pneumoniae
  • S. pseudopneumoniae
Pneumonia, bacteraemia, sinusitis, peritonitis, otitis, conjunctivitis β-Lactams, macrolides, chloramphenicol Penicillin resistance locally common
S. suis Meningitis β-Lactams Associated with pig contact
  • S. albus
  • S. anulatus
  • ‘S. paraguayensis’
  • S. somaliensis
Actinomycetoma Dapsone, co-trimoxazole  
  • S. bikiniensis
  • S. griseus
Bacteraemia, abscess, pericarditis, endocarditis Vancomycin, tetracycline, penicillin Treatment options poorly defined
Succinivibrio S. dextrinosolvens Bacteraemia, pneumonia Penicillin From faecal and gingival flora
Sutterella S. wadsworthensis Appendicitis, peritonitis, abscesses, osteomyelitis Amoxicillin/clavulanate, ticarcillin/clavulanate, meropenem, ceftriaxone One-third of isolates reported to be metronidazole resistant
Suttonella S. indologenes (Kingella indologenes) Endocarditis, eye infection Penicillin (plus gentamicin for endocarditis  
Tannerella T. forsythensis (T. forsythia, T. forsythus) Endodontic infection    
[Tatlockiamaceachernii—see Legionella maceachernii]
[Tatlockia micdadei—see Legionella micdadei]
Tatumella T. ptyseos Bacteraemia, UTI Ampicillin, tetracycline, chloramphenicol, gentamicin The significance of isolates from sputum is unclear
Tissierella T. praeacuta (Bacteroides praeacuta) (Clostridium hastiforme) Bacteraemia Metronidazole  
Trabulsiella T. guamensis Diarrhoea Co-trimoxazole, gentamicin, chloramphenicol Role as possible pathogen uncertain
  • T. amylovorum
  • T. denticola
  • T. lecithinolyticum
  • T. maltophilum
  • T. medium
  • T. parvum
  • T. pectinovorum
  • T. putidum
  • T. scoliodontum
  • T. socranskii
  • ‘T. vincentii’
    Associated with periodontal disease. Role as potential pathogens unclear
‘T. carateum’ Pinta Penicillin Name does not have standing in nomenclature
  • T. minutum
  • ‘T. phagedenis'’
  • ‘T. refringens’
    From genital flora. Considered nonpathogenic but have been isolated from genital lesions
  • T. pallidum
  • ‘T. pallidum endemicum’
Syphilis Penicillin ‘T. pallidum endemicum’ is the agent of nonvenereal endemic syphilis
T. pertenue (‘T. pallidum pertenue’) Yaws Penicillin  
Tropheryma T. whipplei (T. whippelii) Whipple’s disease   Uncultured organism
  • T. inchonensis
  • T. paurometabola
  • T. pulmonis
  • T. strandjordii (T. strandjordae)
  • T. tyrosinosolvens
Septicaemia, cutaneous infections, lung infections β-Lactam (plus aminoglycoside) Line-associated infections in debilitated patients. T. pulmonis isolated from the sputum of a tuberculosis patient
Turicella T. otitidis Otitis, cervical abscess Glycopeptides, β-lactams  
  • U. parvum
  • U. urealyticum
Urethritis Tetracycline, erythromycin  
Vagococcus V. fluvialis   Ampicillin, vancomycin cefotaxime Possible role as pathogen poorly defined
Varibaculum V. cambriensis Abscesses    
  • V. atypical
  • V. dipsar
  • V. montpellierensis
  • V. parvula
Abscesses, bacteraemia Metronidazole  
Vibrio V. alginolyticus Wound infection, ear infection Chloramphenicol, tetracycline Infection associated with aquatic exposure
V. cholerae Cholera Tetracycline  
V. cincinnatiensis Bacteraemia Moxalactam, chloramphenicol, cephalosporins Risk factors for infection not defined
[Vibrio damsela—see Photobacterium damselae]
  • V. fluvialis
  • V. furnissii
  • V. metschnikovii
  • V. mimicus
  • V. parahaemolyticus
Diarrhoea, septicaemia Tetracycline, chloramphenicol Infection associated with ingestion of contaminated water or shellfish
V. harveyi (V. carchariae) Wound infection Cephalosporins, chloramphenicol, gentamicin Infection associated with shark bite. May require debridement
[Vibrio hollisae—see Grimontia hollisae]
  V. vulnificus Wound infection, septicaemia, meningitis, endometritis Tetracycline, penicillins, gentamicin, chloramphenicol Risk factors include aquatic exposure and penetrating fish injury. May require debridement
Wautersiella W. falsenii Bacteraemia, wound infection    
Weeksella W. virosa Peritonitis Imipenem, ampicillin From vaginal flora
[Weeksella zoohelcum—see Bergeyella zoohelcum]
Weissella W. confusa Endocarditis    
Williamsia W. muralis Pulmonary infection    
Wolbachia W. sp. filariasis doxycycline Endosymbiont of filarial nematodes
[Wolinella curva—see Campylobacter curvus]
[Wolinella recta—see Campylobacter rectus]
Xanthomonas X. campestris Bacteraemia    
[Xenorhabdus luminescens—see Photorhabdus luminescens]
  • Y. aldovae
  • Y. bercovieri
  • Y. enterocolitica
  • Y. frederiksenii
  • Y. intermedia
  • Y. kristensenii
  • Y. mollaretii
  • Y. pseudotuberculosis
  • Y. rohdei
Enterocolitis, soft tissue infections, mesenteric lymphadenitis Tetracycline, chloramphenicol, aminoglycosides, fluoroquinolones, cephalosporins Medical significance of manyYersinia spp. is unclear. Antibiotic treatment is not indicated for uncomplicated enteric infection
Y. pestis Plague Streptomycin, tetracycline  
Yokenella Y. regensburgei (Koserella trabulsii) Bacteraemia, wound infection Aminoglycosides, chloramphenicol  

CAPD, continual ambulatory peritoneal dialysis; sp. species; ssp. subspecies; UTI, urinary tract infection.