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Patterns of resistance to anaerobic organisms in Australia

R Munro1

  • 1Microbiology Department, Liverpool Hospital, Sydney, Australia.

Diagnostic Microbiology and Infectious Disease
|July 1, 1989
PubMed

Insights

Metronidazole and sulbactam/ampicillin showed high activity against anaerobic organisms, including beta-lactamase producing Bacteroides species. Ampicillin resistance was common in the Bacteroides fragilis group, while clindamycin and cefoxitin resistance varied.

Area of Science:

  • Medical Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Anaerobic bacteria are significant pathogens in various infections.
  • Understanding antimicrobial resistance patterns is crucial for effective treatment.
  • The Bacteroides fragilis group is a common cause of anaerobic infections.

Purpose of the Study:

  • To investigate antimicrobial resistance patterns in anaerobic organisms isolated from clinical infections.
  • To evaluate the in vitro activity of ampicillin, sulbactam/ampicillin, metronidazole, clindamycin, and cefoxitin against these anaerobes.

Main Methods:

  • Agar dilution method was used to determine minimal inhibitory concentrations (MICs).
  • Two hundred anaerobic isolates from clinically significant infections were tested.
  • Resistance patterns were analyzed for different bacterial groups and beta-lactamase production.

Main Results:

  • Metronidazole and sulbactam/ampicillin were highly active against most anaerobes, including beta-lactamase producing Bacteroides spp. (except B. distasonis).
  • Ampicillin resistance was frequent in the Bacteroides fragilis group and observed in other anaerobes, with or without beta-lactamase production.
  • Clindamycin resistance ranged from 4-18% in B. fragilis group and 7-8% in Clostridium spp. and anaerobic Gram-positive cocci.
  • Cefoxitin resistance varied within the B. fragilis group, particularly in indole-negative subgroups.

Conclusions:

  • Metronidazole and sulbactam/ampicillin are effective agents against a broad spectrum of anaerobic bacteria.
  • Ampicillin resistance is a significant issue, especially in the Bacteroides fragilis group.
  • Monitoring antimicrobial resistance trends is essential for guiding clinical practice and combating infectious diseases.

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