[Study on drug sensitivity against Comamonas testosteroni by Kirby-Bauer disk diffusion method].

Area of Science:

• Microbiology
• Clinical Diagnostics
• Antimicrobial Resistance

Background:

• Comamonas testosteroni (C. testosteroni) is an opportunistic pathogen.
• Accurate drug susceptibility testing is crucial for guiding treatment decisions.
• The Kirby-Bauer (K-B) method is a common disk diffusion technique, while the minimum inhibitory concentration (MIC) method provides quantitative data on drug susceptibility.

Purpose of the Study:

• To evaluate the drug resistance of C. testosteroni using both the K-B method and the MIC method.
• To assess the sensitivity and consistency of the K-B method compared to the standard CLSI-interpreted MIC method for C. testosteroni.
• To determine if K-B method results for C. testosteroni can be reported without CLSI interpretation.

Main Methods:

• The K-B method and MIC method were employed to determine the susceptibility of C. testosteroni to ten antibiotics: Piperacillin, Cefepime, Piperacillin/tazobactam, Imipenem, Meropenem, Amikacin, Gentamicin, Tobramycin, Ceftazidime, and Ciprofloxacin.
• Interpretation standards for Pseudomonas aeruginosa were temporarily applied to the K-B method.
• Coincident rates between the K-B and MIC methods were calculated and compared.

Main Results:

• High agreement rates were observed between the K-B and MIC methods for most tested antibiotics.
• Complete or partial agreement rates ranged from 86.8% for Ciprofloxacin to 100% for Piperacillin/tazobactam, Imipenem, and Meropenem.
• A full non-coincidence rate of only 2.6% was noted, indicating strong concordance between the two methods.

Conclusions:

• The drug susceptibility test results obtained by the K-B method and MIC method are highly consistent for C. testosteroni.
• Microbiology laboratories can report K-B test results for C. testosteroni without CLSI interpretive guidelines.
• The K-B method demonstrates sufficient sensitivity and reliability for detecting drug resistance in C. testosteroni.