Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Anaerobic bacterial infections

John G Bartlett, MD
Section Editor
Stephen B Calderwood, MD
Deputy Editor
Sheila Bond, MD


Anaerobes have been encountered in infections at virtually all anatomic sites, although the frequency of recovery is highly variable. This topic will focus on common infections that involve anaerobic flora endogenous to the host.

Histotoxic clostridial infections are reviewed separately by individual pathogen and/or syndrome (eg, tetanus, botulism, Clostridium difficile infection, gas gangrene, neutropenic enterocolitis due to Clostridium septicum). The history of anaerobes, the composition of normal flora in humans, and the pathophysiology, clinical clues, and recovery of these organisms are also discussed separately. (See "Anaerobic bacteria: History and role in normal human flora" and "Pathophysiology, clinical clues, and recovery of organisms in anaerobic infections".)


Clinical clues to anaerobic infection include:

Putrid drainage (considered diagnostic of anaerobic infection)

Polymicrobial flora on Gram stain of exudates

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Jun 19, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Swartz MN. Central nervous infections. In: Anaerobic Infections in Humans, Finegold SM, George WL (Eds), Academic Press, San Diego 1989. p.156.
  2. Brook I. The role of anaerobic bacteria in otitis media: microbiology, pathogenesis, and implications on therapy. Am J Otolaryngol 1987; 8:109.
  3. Brook I, Frazier EH. Aerobic and anaerobic microbiology in intra-abdominal infections associated with diverticulitis. J Med Microbiol 2000; 49:827.
  4. Swenson RM, Lorber B, Michaelson TC, Spaulding EH. The bacteriology of intra-abdominal infections. Arch Surg 1974; 109:398.
  5. Brook I, Frazier EH. Microbiology of subphrenic abscesses: a 14-year experience. Am Surg 1999; 65:1049.
  6. Sabbaj J, Sutter VL, Finegold SM. Anaerobic pyogenic liver abscess. Ann Intern Med 1972; 77:627.
  7. Sweet RL. Role of bacterial vaginosis in pelvic inflammatory disease. Clin Infect Dis 1995; 20 Suppl 2:S271.
  8. Sweet RL, Schachter J, Landers DV, et al. Treatment of hospitalized patients with acute pelvic inflammatory disease: comparison of cefotetan plus doxycycline and cefoxitin plus doxycycline. Am J Obstet Gynecol 1988; 158:736.
  9. Rosene K, Eschenbach DA, Tompkins LS, et al. Polymicrobial early postpartum endometritis with facultative and anaerobic bacteria, genital mycoplasmas, and Chlamydia trachomatis: treatment with piperacillin or cefoxitin. J Infect Dis 1986; 153:1028.
  10. Meislin HW, Lerner SA, Graves MH, et al. Cutaneous abscesses. Anaerobic and aerobic bacteriology and outpatient management. Ann Intern Med 1977; 87:145.
  11. Versluijs-Ossewaarde FN, Roumen RM, Goris RJ. Subareolar breast abscesses: characteristics and results of surgical treatment. Breast J 2005; 11:179.
  12. Pearson HE, Smiley DF. Bacteroides in pilonidal sinuses. Am J Surg 1968; 115:336.
  13. Brook I. Bacteriologic study of paronychia in children. Am J Surg 1981; 141:703.
  14. Bartlett JG, Condon RE, Gorbach SL, et al. Veterans Administration Cooperative Study on Bowel Preparation for Elective Colorectal Operations: impact of oral antibiotic regimen on colonic flora, wound irrigation cultures and bacteriology of septic complications. Ann Surg 1978; 188:249.
  15. Sanderson PJ, Wren MW, Baldwin AW. Anaerobic organisms in postoperative wounds. J Clin Pathol 1979; 32:143.
  16. Goldstein EJ, Citron DM, Finegold SM. Role of anaerobic bacteria in bite-wound infections. Rev Infect Dis 1984; 6 Suppl 1:S177.
  17. Louie TJ, Bartlett JG, Tally FP, Gorbach SL. Aerobic and anaerobic bacteria in diabetic foot ulcers. Ann Intern Med 1976; 85:461.
  18. Salonen JH, Eerola E, Meurman O. Clinical significance and outcome of anaerobic bacteremia. Clin Infect Dis 1998; 26:1413.
  20. Frederick J, Braude AI. Anaerobic infection of the paranasal sinuses. N Engl J Med 1974; 290:135.
  21. Bartlett JG, O'Keefe P. The bacteriology of perimandibular space infections. J Oral Surg 1979; 37:407.
  22. Chow AW, Roser SM, Brady FA. Orofacial odontogenic infections. Ann Intern Med 1978; 88:392.
  23. Flodström A, Hallander HO. Microbiological aspects on peritonsillar abscesses. Scand J Infect Dis 1976; 8:157.
  24. Mitchelmore IJ, Prior AJ, Montgomery PQ, Tabaqchali S. Microbiological features and pathogenesis of peritonsillar abscesses. Eur J Clin Microbiol Infect Dis 1995; 14:870.
  25. Williams BL, McCann GF, Schoenknecht FD. Bacteriology of dental abscesses of endodontic origin. J Clin Microbiol 1983; 18:770.
  26. Bartlett JG, Finegold SM. Anaerobic infections of the lung and pleural space. Am Rev Respir Dis 1974; 110:56.
  27. Lorber B, Swenson RM. Bacteriology of aspiration pneumonia. A prospective study of community- and hospital-acquired cases. Ann Intern Med 1974; 81:329.
  28. Beerens H, Tahon-Castel M. Infections Humaines à Bactéries Anaérobies Nontoxigènes, Presses Académiques Européenes, Bruxelles 1965. p.91.
  29. Varkey B, Rose HD, Kutty CP, Politis J. Empyema thoracis during a ten-year period. Analysis of 72 cases and comparison to a previous study (1952 to 1967). Arch Intern Med 1981; 141:1771.
  30. Ries K, Levison ME, Kaye D. Transtracheal aspiration in pulmonary infection. Arch Intern Med 1974; 133:453.
  31. Pollock HM, Hawkins EL, Bonner JR, et al. Diagnosis of bacterial pulmonary infections with quantitative protected catheter cultures obtained during bronchoscopy. J Clin Microbiol 1983; 17:255.
  32. Bartlett JG, O'Keefe P, Tally FP, et al. Bacteriology of hospital-acquired pneumonia. Arch Intern Med 1986; 146:868.
  33. Stone HH, Strom PR, Fabian TC, Dunlop WE. Third-generation cephalosporins for polymicrobial surgical sepsis. Arch Surg 1983; 118:193.
  34. Gorbach SL, Bartlett JG. Anaerobic infections. 1. N Engl J Med 1974; 290:1177.
  35. Thadepalli H, Gorbach SL, Keith L. Anaerobic infections of the female genital tract: bacteriologic and therapeutic aspects. Am J Obstet Gynecol 1973; 117:1034.
  36. Swenson RM, Michaelson TC, Daly MJ, Spaulding EH. Anaerobic bacterial infections of the female genital tract. Obstet Gynecol 1973; 42:538.
  37. Ledger WJ, Gee CL, Pollin R, et al. The use of pr-reduced media and a portable jar for the collection of anaerobic organisms for clinical sites of infection. Am J Obstet Gynecol 1976; 125:677.
  38. Altemeier, WA. The anaerobic streptococci in tuboovarian abscess. Am J Obstet Gynecol 1940; 39:1038.
  39. Eschenbach DA, Buchanan TM, Pollock HM, et al. Polymicrobial etiology of acute pelvic inflammatory disease. N Engl J Med 1975; 293:166.
  40. Chow AW, Marshall JR, Guze LB. A double-blind comparison of clindamycin with penicillin plus chloramphenicol in treatment of septic abortion. J Infect Dis 1977; 135 Suppl:S35.
  41. Whitehead SM, Leach RD, Eykyn SJ, Phillips I. The aetiology of perirectal sepsis. Br J Surg 1982; 69:166.
  42. Stone HH, Martin JD Jr. Synergistic necrotizing cellulitis. Ann Surg 1972; 175:702.
  43. Elliott D, Kufera JA, Myers RA. The microbiology of necrotizing soft tissue infections. Am J Surg 2000; 179:361.
  44. Chandler MT, Morton ES, Byrd RP Jr, et al. Reevaluation of anaerobic blood cultures in a Veteran population. South Med J 2000; 93:986.
  45. Snydman DR, Jacobus NV, McDermott LA, et al. National survey on the susceptibility of Bacteroides fragilis group: report and analysis of trends in the United States from 1997 to 2004. Antimicrob Agents Chemother 2007; 51:1649.
  46. Methods for antimicrobial susceptibility testing of anaerobic bacteria, 8th Edition. Approved standard M11-A8. Clinical and Laboratory Standards Institute 2012; 32(5).
  47. Nguyen MH, Yu VL, Morris AJ, et al. Antimicrobial resistance and clinical outcome of Bacteroides bacteremia: findings of a multicenter prospective observational trial. Clin Infect Dis 2000; 30:870.
  48. Zahar JR, Farhat H, Chachaty E, et al. Incidence and clinical significance of anaerobic bacteraemia in cancer patients: a 6-year retrospective study. Clin Microbiol Infect 2005; 11:724.
  49. Hecht DW. Prevalence of antibiotic resistance in anaerobic bacteria: worrisome developments. Clin Infect Dis 2004; 39:92.
  50. Jamal W, Shahin M, Rotimi VO. Surveillance and trends of antimicrobial resistance among clinical isolates of anaerobes in Kuwait hospitals from 2002 to 2007. Anaerobe 2010; 16:1.
  51. Goldstein EJ, Citron DM. Activity of a novel carbapenem, doripenem, against anaerobic pathogens. Diagn Microbiol Infect Dis 2009; 63:447.
  52. Karlowsky JA, Walkty AJ, Adam HJ, et al. Prevalence of antimicrobial resistance among clinical isolates of Bacteroides fragilis group in Canada in 2010-2011: CANWARD surveillance study. Antimicrob Agents Chemother 2012; 56:1247.
  53. Fernández-Canigia L, Litterio M, Legaria MC, et al. First national survey of antibiotic susceptibility of the Bacteroides fragilis group: emerging resistance to carbapenems in Argentina. Antimicrob Agents Chemother 2012; 56:1309.
  54. Wexler HM. Bacteroides: the good, the bad, and the nitty-gritty. Clin Microbiol Rev 2007; 20:593.
  55. Snydman DR, Jacobus NV, McDermott LA, et al. Update on resistance of Bacteroides fragilis group and related species with special attention to carbapenems 2006-2009. Anaerobe 2011; 17:147.
  56. Snydman DR, Jacobus NV, McDermott LA, et al. Lessons learned from the anaerobe survey: historical perspective and review of the most recent data (2005-2007). Clin Infect Dis 2010; 50 Suppl 1:S26.
  57. Snydman DR, Jacobus NV, McDermott LA, et al. National survey on the susceptibility of Bacteroides Fragilis Group: report and analysis of trends for 1997-2000. Clin Infect Dis 2002; 35:S126.
  58. Snydman DR, Jacobus NV, McDermott LA. In vitro activities of doripenem, a new broad-spectrum carbapenem, against recently collected clinical anaerobic isolates, with emphasis on the Bacteroides fragilis group. Antimicrob Agents Chemother 2008; 52:4492.
  59. Paterson DL, Depestel DD. Doripenem. Clin Infect Dis 2009; 49:291.
  60. Ang L, Brenwald NP, Walker RM, et al. Carbapenem resistance in Bacteroides fragilis. J Antimicrob Chemother 2007; 59:1042.
  61. Liu CY, Huang YT, Liao CH, et al. Increasing trends in antimicrobial resistance among clinically important anaerobes and Bacteroides fragilis isolates causing nosocomial infections: emerging resistance to carbapenems. Antimicrob Agents Chemother 2008; 52:3161.
  62. Pumbwe L, Wareham DW, Aduse-Opoku J, et al. Genetic analysis of mechanisms of multidrug resistance in a clinical isolate of Bacteroides fragilis. Clin Microbiol Infect 2007; 13:183.
  63. Centers for Disease Control and Prevention (CDC). Multidrug-resistant bacteroides fragilis--Seattle, Washington, 2013. MMWR Morb Mortal Wkly Rep 2013; 62:694.
  64. Sherwood JE, Fraser S, Citron DM, et al. Multi-drug resistant Bacteroides fragilis recovered from blood and severe leg wounds caused by an improvised explosive device (IED) in Afghanistan. Anaerobe 2011; 17:152.
  65. Jacinto RC, Montagner F, Signoretti FG, et al. Frequency, microbial interactions, and antimicrobial susceptibility of Fusobacterium nucleatum and Fusobacterium necrophorum isolated from primary endodontic infections. J Endod 2008; 34:1451.
  66. Labbé AC, Bourgault AM, Vincelette J, et al. Trends in antimicrobial resistance among clinical isolates of the Bacteroides fragilis group from 1992 to 1997 in Montreal, Canada. Antimicrob Agents Chemother 1999; 43:2517.
  67. Halton K, Arora V, Singh V, et al. Bacterial colonization on writing pens touched by healthcare professionals and hospitalized patients with and without cleaning the pen with alcohol-based hand sanitizing agent. Clin Microbiol Infect 2011; 17:868.
  68. Gorbach SL, Thadepalli H. Clindamycin in pure and mixed anaerobic infections. Arch Intern Med 1974; 134:87.
  69. Siqueira JF Jr, Rôças IN. Microbiology and treatment of acute apical abscesses. Clin Microbiol Rev 2013; 26:255.
  70. Enwonwu CO, Falkler WA Jr, Phillips RS. Noma (cancrum oris). Lancet 2006; 368:147.
  71. Falkler WA Jr, Enwonwu CO, Idigbe EO. Microbiological understandings and mysteries of noma (cancrum oris). Oral Dis 1999; 5:150.
  72. Jaworsky D, Reynolds S, Chow AW. Extracranial head and neck infections. Crit Care Clin 2013; 29:443.
  73. Centor RM, Atkinson TP, Ratliff AE, et al. The clinical presentation of Fusobacterium-positive and streptococcal-positive pharyngitis in a university health clinic: a cross-sectional study. Ann Intern Med 2015; 162:241.
  74. Hedin K, Bieber L, Lindh M, Sundqvist M. The aetiology of pharyngotonsillitis in adolescents and adults - Fusobacterium necrophorum is commonly found. Clin Microbiol Infect 2015; 21:263.e1.
  75. Jensen A, Hansen TM, Bank S, et al. Fusobacterium necrophorum tonsillitis: an important cause of tonsillitis in adolescents and young adults. Clin Microbiol Infect 2015; 21:266.e1.
  76. Panchavati PK, Kar B, Hassoun A, Centor RM. Fusobacterium necrophorum tonsillitis with mild case of Lemierre's syndrome. Anaerobe 2017; 43:102.
  77. Klug TE, Rusan M, Fuursted K, et al. A systematic review of Fusobacterium necrophorum-positive acute tonsillitis: prevalence, methods of detection, patient characteristics, and the usefulness of the Centor score. Eur J Clin Microbiol Infect Dis 2016; 35:1903.
  78. Bartlett JG. Anaerobic bacterial infection of the lung. Anaerobe 2012; 18:235.
  79. Bartlett JG. Anaerobic bacterial pneumonitis. Am Rev Respir Dis 1979; 119:19.
  80. Cereija TB, Castro J, Alves P, Cerca N. Influence of anaerobic conditions on vaginal microbiota recovery from bacterial vaginosis patients. Sex Transm Infect 2013; 89:307.
  81. Fredricks DN, Fiedler TL, Marrazzo JM. Molecular identification of bacteria associated with bacterial vaginosis. N Engl J Med 2005; 353:1899.
  82. Crane JK, Hohman DW, Nodzo SR, Duquin TR. Antimicrobial susceptibility of Propionibacterium acnes isolates from shoulder surgery. Antimicrob Agents Chemother 2013; 57:3424.
  83. Butler-Wu SM, Burns EM, Pottinger PS, et al. Optimization of periprosthetic culture for diagnosis of Propionibacterium acnes prosthetic joint infection. J Clin Microbiol 2011; 49:2490.
  84. Levy PY, Fenollar F, Stein A, et al. Propionibacterium acnes postoperative shoulder arthritis: an emerging clinical entity. Clin Infect Dis 2008; 46:1884.
  85. Al Benwan K, Al Mulla A, Rotimi VO. A study of the microbiology of diabetic foot infections in a teaching hospital in Kuwait. J Infect Public Health 2012; 5:1.
  86. Bryan CS, Dew CE, Reynolds KL. Bacteremia associated with decubitus ulcers. Arch Intern Med 1983; 143:2093.
  87. Sapico FL, Canawati HN, Witte JL, et al. Quantitative aerobic and anaerobic bacteriology of infected diabetic feet. J Clin Microbiol 1980; 12:413.
  88. Wheat LJ, Allen SD, Henry M, et al. Diabetic foot infections. Bacteriologic analysis. Arch Intern Med 1986; 146:1935.
  89. Lipsky BA, Berendt AR, Cornia PB, et al. Executive summary: 2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. Clin Infect Dis 2012; 54:1679.
  90. Bartlett JG, Onderdonk AB, Louie T, et al. A review. Lessons from an animal model of intra-abdominal sepsis. Arch Surg 1978; 113:853.
  91. Kasper DL, Onderdonk AB, Polk BF, Bartlett JG. Surface antigens as virulence factors in infection with Bacteroides fragilis. Rev Infect Dis 1979; 1:278.
  92. Bartlett JG, Louie TJ, Gorbach SL, Onderdonk AB. Therapeutic efficacy of 29 antimicrobial regimens in experimental intraabdominal sepsis. Rev Infect Dis 1981; 3:535.
  93. Wilson WR, Martin WJ, Wilkowske CJ, Washington JA 2nd. Anaerobic bacteremia. Mayo Clin Proc 1972; 47:639.
  94. James PA, al-Shafi KM. Clinical value of anaerobic blood culture: a retrospective analysis of positive patient episodes. J Clin Pathol 2000; 53:231.
  95. Finegold SM, George WL, Mulligan ME. Anaerobic infections. Part II. Dis Mon 1985; 31:1.
  96. Lassmann B, Gustafson DR, Wood CM, Rosenblatt JE. Reemergence of anaerobic bacteremia. Clin Infect Dis 2007; 44:895.
  97. Fenner L, Widmer AF, Straub C, Frei R. Is the incidence of anaerobic bacteremia decreasing? Analysis of 114,000 blood cultures over a ten-year period. J Clin Microbiol 2008; 46:2432.
  98. Hecht DW. Routine anaerobic blood cultures: back where we started? Clin Infect Dis 2007; 44:901.
  99. Redondo MC, Arbo MD, Grindlinger J, Snydman DR. Attributable mortality of bacteremia associated with the Bacteroides fragilis group. Clin Infect Dis 1995; 20:1492.