Ampicillinase C Beta-lactamase Producers among Isolates of Enterobacteriaceae in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Abstract

Introduction: Ampicillinase C beta-lactamase-producing organisms are often resistant to multiple antimicrobial agents, and therapeutic options against these pathogens are limited. Limited information is available regarding Ampicillinase C beta-lactamase producers. The aim of this study was to find out the prevalence of Ampicillinase C beta-lactamase producers among isolates of Enterobacteriaceae in a tertiary care centre.

Methods: A descriptive cross-sectional study was carried out in the Clinical Microbiology Laboratory of a tertiary care centre from May 2021 to October 2021. Ethical approval was received from the Institutional Review Committee (Reference number: 044-077/078). Isolates of Enterobacteriaceae from various clinical samples were collected by convenience sampling. Ampicillinase C screening for beta-lactamase producers among the Enterobacteriaceae isolates was done using cefoxitin (30 μg) disc. Detection of Ampicillinase C beta-lactamase producers among the screen-positive isolates was done by cefoxitin-cloxacillin double-disc synergy test. An increase in the zone size of ≥4 mm was considered as Ampicillinase C beta-lactamase producers. Point estimate and 95% Confidence Interval were calculated.

Results: Among the total 481 isolates of Enterobacteriaceae, 49 (10.19%) (7.50-12.90, 95 % Confidence Interval) were detected as Ampicillinase C beta-lactamase producers among isolates of Enterobacteriaceae.

Conclusions: The prevalence of Ampicillinase C beta-lactamase producers was lower than in other studies done in similar settings. Meropenem could be a drug of choice for the treatment of infections due to Ampicillinase C beta-lactamase-producing gram-negative bacteria.