微生物および生化学技術ジャーナル

概要

Detection of β-lactamase in Haemophilus influenzae Isolates by Double Disk Synergy Test

Harunur Rashid and Mahbubur Rahman

A total of 90 isolates of Haemophilus influenzae were included in this study. Among them 47.8% were resistant to ampicillin and amoxicillin. Of the 90 isolates, 43 were positive for β-lactamase by defense test and the rest (47) were β-lactamase negative. Interestingly, all the β-lactamase positive isolates were ampicillin resistant. No isolate of H. influenzae was β-lactamase negative ampicillin resistant (BLNAR). All β-lactamase positive ampicillin resistant (BLPAR) isolates were also positive for β-lactamase by double disk (Ampicillin and Amoxicillin/clavulanate) technique. And all β-lactamase-negative isolates were also negative double disk synergy test. Both the sensitivity and specificity of double disk synergy test were 100% compared to defense test. So, double disk synergy test can be used to detect β-lactamase as an alternative of the cefinase test by incorporating an augmentin (amoxicillin/clavulanic acid) disk during antimicrobial susceptibility testing by disk diffusion method.