Antimicrobial susceptibility of Clostridium difficile determined by disc diffusion and breakpoint methods

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Clostridium difficile is a significant cause of healthcare-associated infections.
• Accurate antimicrobial susceptibility testing is crucial for effective treatment.
• Evaluating different testing methodologies ensures reliable results.

Purpose of the Study:

• To compare disc diffusion and breakpoint methods for assessing Clostridium difficile susceptibility.
• To determine the resistance patterns of Clostridium difficile isolates to key antimicrobial agents.
• To identify discrepancies in antimicrobial susceptibility testing results.

Main Methods:

• Susceptibility testing of 160 Clostridium difficile isolates against eight antimicrobial agents.
• Utilized both disc diffusion and breakpoint methodologies for comparison.
• Analyzed agreement and discrepancies between the two testing methods.

Main Results:

• High agreement between disc diffusion and breakpoint methods for most agents.
• Overestimation of resistance to penicillin G and clindamycin by disc diffusion.
• Over 90% of isolates were sensitive to both metronidazole and vancomycin.
• Identified isolates with multidrug resistance to penicillin G, tetracycline, erythromycin, and clindamycin.

Conclusions:

• Disc diffusion and breakpoint methods show good overall agreement for Clostridium difficile susceptibility.
• Disc diffusion may overestimate resistance for certain antibiotics like penicillin G and clindamycin.
• Metronidazole and vancomycin remain highly effective against Clostridium difficile isolates studied.