Anaerobic bacteria

• Obligate anaerobic bacteria cannot survive in areas of high oxygen content or high redox potential.
• Bacteria produce toxic metabolites from oxygen; obligate anaerobes lack certain enzymes, such as catalase and superoxide dismutase, that detoxify these metabolites.
• Most anaerobes in the normal flora do not form spores, and many opportunistic infections involve these bacteria.
• Obligate anaerobes form 9599% of the total bacterial mass in the normal flora of the intestine, and also inhabit the oral cavity, respiratory tract and genitourinary tract.
• Abdominal surgery or gut injury often result in infections with Enterobacteriaceae, which are facultative anaerobes.
• Wounds may be contaminated with spore-forming anaerobic bacteria such as Clostridiumspp, which are common in the environment. Spore-forming bacteria often produce exotoxins, such as the theta toxin of Clostridium perfringens  Clostridium perfringens  .

Non-spore-forming anaerobes

Spore-forming anaerobes

Pathogenesis

Disease associated with anaerobic infections

Diagnosis and treatment

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Båverud V (2002) Clostridium difficile infections in animals with special reference to the horse. A review. Vet Q 24 (4), 203-219 PubMed.
• Jones R L (2000) Clostridial enterocolitis. Vet Clin North Am Equine Pract 16 (3), 471485 PubMed.
• Racklyeft D J, Raidal S & Love D N (2000) Towards an understanding of equine pleuropneumonia: factors relevant for control. Aust Vet J 78 (5), 334-338 PubMed.
• Racklyeft D J & Love D N (2000) Bacterial infection of the lower respiratory tract in 34 horses. Aust Vet J 78 (8), 549-559 PubMed.
• Weese J S, Staempfli H R & Prescott J F (2000) Survival of Clostridium difficile and its toxins in equine feces: implications for diagnostic test selection and interpretation. J Vet Diagn Invest 12 (4), 332-336 PubMed.
• Samitz E M, Jang S S & Hirsh D C (1996) In vitro susceptibilities of selected obligate anaerobic bacteria obtained from bovine and equine sources to ceftiofur. J Vet Diagn Invest 8 (1), 121-123 PubMed.
• Hariharan H, Lamey K & Heaney S (1995) Isolation of obligate anaerobic bacteria from clinical specimens. Can Vet J 36 (3), 173 PubMed.
• Hariharan H, Richardson G, Horney B et al (1994) Isolation of Bacteroides ureolyticus from the equine endometrium. J Vet Diagn Invest 6 (1), 127-130 PubMed.
• Jang S S & Hirsh D C (1994) Characterization, distribution, and microbiological associations of Fusobacteriumspp. in clinical specimens of animal origin. J Clin Microbiol 32 (2), 384-387 PubMed.
• Traub-Dargatz J L & Jones R L (1993) Clostridia-associated enterocolitis in adult horses and foals. Vet Clin North Am Equine Pract 9 (2), 411-421 PubMed.
• Bailey G D & Love D N (1991) Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections. Vet Microbiol 26 (4), 367-379 PubMed.
• Jang S S & Hirsh D C (1991) Identity of Bacteroides isolates and previously named Bacteroidesspp in clinical specimens of animal origin. Am J Vet Res 52 (5), 738-741 PubMed.
• Sweeney R W, Sweeney C R & Weiher J (1991) Clinical use of metronidazole in horses: 200 cases (1984-1989). JAVMA 198 (6), 1045-1048 PubMed.
• Sweeney C R, Holcombe S J, Barningham S C & Beech J (1991) Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes. JAVMA 198 (5), 839-842 PubMed.
• Carlson G P & O'Brien M A (1990) Anaerobic bacterial pneumonia with septicemia in two racehorses. JAVMA 196 (6), 941-943 PubMed.
• Reimer J M, Reef V B & Spencer P A (1989) Ultrasonography as a diagnostic aid in horses with anaerobic bacterial pleuropneumonia and/or pulmonary abscessation: 27 cases (1984-1986). JAVMA 194 (2), 278-282 PubMed.
• Kanoe M, Hirabayashi T, Anzai T, Imagawa H & Tanaka Y (1988) Isolation of obligate anaerobic and some other bacteria from equine purulent lesions. Br Vet J 144 (4), 374-378 PubMed.
• Mackintosh M E & Colles C M (1987) Anaerobic bacteria associated with dental abscesses in the horse and donkey. Eq Vet J 19, 360-362 PubMed.
• Mair T S & Yeo S P (1987) Equine pleuropneumonia: the importance of anaerobic bacteria and the potential value of metronidazole in treatment. Vet Rec 121 (5), 109-110 PubMed.
• Ricketts S W & Mackintosh M E (1987) Role of anaerobic bacteria in equine endometritis. J Reprod Fert S35, 343-351 PubMed.
• Sweeney C R, Divers T J & Benson C E (1985) Anaerobic bacteria in 21 horses with pleuropneumonia. JAVMA 187 (7), 721-724 PubMed.