ISSN 2398-2950      

Anaerobic bacterial infections: overview

ffelis
Contributor(s):

Sarah Binns

Karen Coyne


Introduction

  • Anaerobic bacteria do not require oxygen for growth.
  • There are three types of anaerobic bacteria, obligate anaerobes, aerotolerant anaerobes and facultative anaerobes:
    • Obligate anaerobes cannot use oxygen for growth and will not survive in areas of high oxygen content or high redox potential.
    • Aerotolerant anaerobes cannot use oxygen for growth but will tolerate the presence of it.
    • Facultative anaerobes can grow without oxygen, but may utilize oxygen if it is present.
  • Obligate anaerobes can be either gram-positive or gram-negative rods or cocci.
  • Bacteria produce toxic metabolites from oxygen. Obligate anaerobes lack certain enzymes, such as catalase and superoxide dismutase, that detoxify these metabolites.
  • Obligate anaerobes make up a significant portion of the normal bacteria flora of cats. They form 95-99% of the total bacterial mass in the normal flora of the intestine, and also inhabit the oral cavity, respiratory tract and genitourinary tract.
  • Studies investigating the normal flora of the duodenum of healthy cats have found anaerobic bacteria including:
    •  Bacteroides fragilis group, B. UreolyticusBacteroides spp   Bacteroides fragilis  .
    •  Clostridium perfringens Clostridium perfringensC. chauvoeiC. tertiumClostridium spp   Clostridia spp.
    •  Eubacterium lentumE. moniliformisEubacterium spp.
    •  Fusobacterium nucleatum.
    •  Peptostreptococcus spp.
    •  Prevotella intermedia.
  • Studies investigating the normal flora of the vagina of healthy cats have found anaerobic bacteria including:
  • Some studies have shown that anaerobic bacteria is more predominant in male genital tracts that genital tracts of female adult cats.
  • Studies investigating the gingival flora in healthy cats have found anaerobic bacteria including:
    •  Bacteroides spp.
    •  Prevotella spp.
    •  Fusobacterium spp.
    •  Clostridium spp.
    •  Peptostreptococcus spp.
  • Most anaerobes in the normal flora do not form spores.
  • Anaerobic bacteria play an important role in protection of mucosal surfaces from interactions with other pathogens.
  • The majority of anaerobic infections begin with a break in the skin or mucous membranes that permits normally present bacteria to invade underlying tissues.
  • The virulence of anaerobic infections increases if they produce enzymes or toxins capable of destroying surrounding tissue, eg BacteroidesFusobacterium and Clostridium, all release enzymes or toxins.
  • Wounds may be contaminated with spore-forming anaerobic bacteria such as Clostridium spp, which are common in the environment.

Non-spore-forming anaerobes

  • Anaerobic bacteria can be identified by their reaction to gram stain and the presence/absence of spores:
    •  Bacteroides spp. Gram negative rod.
    •  Fusobacterium spp. Gram negative rod.
    •  Prevotella spp. Gram negative rod.
    •  Porphyromonas spp. Gram negative rod.
    •  Peptostreptococcus anaerobius. Gram positive coccus. 
    •  Eubacterium spp. Gram positive coccus.

Spore-forming anaerobes   

  •  Clostridium spp. Gram positive rod (spores).
  •  Clostridiaare found in the environment but also in the intestines of many species. They include:

Pathogenesis

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Clinical findings associated with anaerobic infections

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diseases associated with anaerobic bacterial infections

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Diagnosis

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Treatment

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Nagy E, Urbán E, Nord C E et al (2011) Antimicrobial susceptibility of Bacteroides fragilis group isolates in Europe: 20 years of experience. Clin Microbiol Infect 17 (3), 371-379 PubMed.
  • McKenzie E, Riehl J, Banse H et al (2010) Prevalence of diarrhea and enteropathogens in racing sled dogs. J Vet Intern Med 24 (1), 97-103 PubMed.
  • Johnson L R, Kass P H (2009) Effect of sample collection methodology on nasal culture results in cats. J Feline Med Surg 11 (8), 645-649 PubMed.
  • Wang A L, Ledbetter E C, Kern T J (2009) Orbital abscess bacterial isolates and in vitro antimicrobial susceptibility patterns in dogs and cats. Vet Ophthalmol 12 (2), 91-96 PubMed.
  • Ledbetter E C, Scarlett J M (2008) Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals. Vet Ophthalmol 11 (2), 114-122 PubMed.
  • Meyers B, Schoeman J P, Goddard A et al (2008) The bacteriology and antimicrobial susceptibility of infected and non-infected dog bite wounds: fifty cases. Vet Microbiol 127 (3-4), 360-368 PubMed.
  • Greiner M, Wolf G, Hartmann K (2007) Bacteraemia in 66 cats and antimicrobial susceptibility of the isolates (1995-2004). J Feline Med Surg (5), 404-410 PubMed.
  • Roy J, Messier S, Labrecque O et al (2007) Clinical and in vitro efficacy of amoxicillin against bacteria associated with feline skin wounds and abscesses. Can Vet J 48 (6), 607-611 PubMed.
  • Radice M, Martino P A, Reiter A M (2006) Evaluation of subgingival bacteria in the dog and susceptibility to commonly used antibiotics. J Vet Dent 23 (4), 219-224 PubMed.
  • Barrs V R, Allan G S, Martin P et al (2005) Feline pyothorax: a retrospective study of 27 cases in Australia. J Feline Med Surg (4), 211-222 PubMed.
  • Conrads G, Citron D M, Mutters R et al (2004) Fusobacterium canifelinum sp. nov., from the oral cavity of cats and dogs. Syst Appl Microbiol 27 (4), 407-413 PubMed.
  • Ström Holst B, Bergström A, Lagerstedt A S et al (2003) Characterization of the bacterial population of the genital tract of adult cats. Am J Vet Res 64 (8), 963-968 PubMed.
  • Radaelli S T, Platt S R (2002) Bacterial meningoencephalomyelitis in dogs: a retrospective study of 23 cases (1990-1999). J Vet Intern Med 16 (2), 159-163 PubMed.
  • Weese J S, Staempfli H R, Prescott J F et al (2001) The roles of Clostridium difficile and enterotoxigenic Clostridium perfringens in diarrhea in dogs. J Vet Intern Med 15 (4), 374-378 PubMed.
  • Walker R D, Ortizb B L, Render A E (1999) Anaerobic infections in animals and therapeutic considerations. Anaerobe  (3-4),  279-286 VetMedResource.
  • Papasouliotis K, Sparkes A H, Werrett G et al (1998) Assessment of the bacterial flora of the proximal part of the small intestine in healthy cats, and the effect of sample collection method. Am J Vet Res 59 (1), 48-51 PubMed.
  • Jang S S, Breher J E, Dabaco L A et al (1997) Organisms isolated from dogs and cats with anaerobic infections and susceptibility to selected antimicrobial agents. J Am Vet Med Assoc 210 (11), 1610-1614 PubMed.  
  • Hariharan H, Lamey K, Heaney S (1995) Isolation of obligate anaerobic bacteria from clinical specimens. Can Vet J 36 (3), 173 PubMed.
  • Jang S S & Hirsh D C (1994) Characterization, distribution, and microbiological associations of Fusobacterium spp. in clinical specimens of animal origin. J Clin Microbiol 32 (2), 384-387 PubMed.
  • Jang S S & Hirsh D C (1991) Identity of Bacteroides isolates and previously named Bacteroides spp in clinical specimens of animal origin. Am J Vet Res 52 (5), 738-741 PubMed.
  • Goldstein E J, Citron D M, Finegold S M (1984) Role of anaerobic bacteria in bite-wound infections. Rev Infect Dis 6 (Suppl 1), S177-183 PubMed.

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