Clindamycin resistance in anaerobic bacteria

Area of Science:

• Microbiology
• Molecular Biology
• Infectious Diseases

Background:

• Anaerobic bacteria, especially the Bacteroides fragilis group, are significant human pathogens.
• Antimicrobial resistance in these bacteria poses a growing threat to effective treatment.
• Understanding resistance mechanisms and transfer is crucial for clinical management.

Purpose of the Study:

• To review current knowledge on antimicrobial resistance and transfer mechanisms in anaerobic bacteria.
• To highlight specific resistance patterns in Bacteroides species, including beta-lactam, tetracycline, and clindamycin resistance.
• To discuss the implications of transferable resistance for public health.

Main Methods:

• Literature review of studies on antimicrobial resistance in anaerobic bacteria.
• Analysis of documented resistance mechanisms (e.g., beta-lactamases, drug efflux, ribosomal modification).
• Examination of evidence for plasmid-mediated and chromosomal resistance transfer.

Main Results:

• Widespread beta-lactam resistance in B. fragilis group mediated by chromosomal beta-lactamases; emerging penicillin resistance in other Bacteroides species.
• Tetracycline resistance in B. fragilis due to lack of intracellular drug accumulation, with common transfer but no isolated transfer factor.
• Clindamycin-erythromycin resistance mechanisms likely similar to macrolide-lincosamide-streptinogramin resistance in aerobic bacteria, with transferable resistance factors identified (pBFTM10, pIP410).
• Common resistance determinants found on plasmids and chromosomes, potentially residing on transposons.
• DNA homology studies reveal multiple clindamycin resistance types in Bacteroides, with a newly recognized transferable determinant.
• Local outbreaks of clindamycin resistance reported in the US and Europe.
• Multi-center study in 1983 showed 5% resistance in B. fragilis and 1% in other Bacteroides species; clindamycin resistance rates remained steady in B. fragilis group.

Conclusions:

• Antimicrobial resistance, particularly to beta-lactams, tetracyclines, and clindamycin, is a significant issue in anaerobic bacteria.
• Transferable resistance mechanisms contribute to the spread of resistance, necessitating ongoing surveillance.
• Further research into novel resistance determinants and transfer factors is needed to combat emerging resistance threats.