Prevalence of Extended Spectrum β-Lactamase, Metallo β-Lactamase, and AmpC β-Lactamase among Gram Negative Bacilli Recovered from Burn Wound Infection

Abstract

Introduction: Infections are the major cause of morbidity and mortality in burn patients. The ESBL, MBL and AmpC are the major mediators of antimicrobial resistance in gram negative bacteria. Early detection of ESBL, MBL and AmpC β -lactamases is crucial to establish appropriate anti-microbial therapy to prevent their inter-hospital dissemination. This study was done to find the prevalence of ESBL, MBL, and AmpC β-lactamases mediated resistance among gram negative isolates. Methodology: All (160) gram negative bacteria were identified by standard microbiological procedure. Antibiotic susceptibility was performed according to CLSI guidelines. All gram negative isolates were screened for their ability to produce extended spectrum β-lactamases enzyme by using ceftazidime clavulanic acid combination disc method (combined disc diffusion test), AmpC β lactamases enzyme using AmpC disc test and metallo β lactamases enzyme by using double disc synergy test (DDST), combined EDTA disc test (CDT), and modified Hodge test (MHT). Results: Out of 160 gram negative isolates, 113 (70.62%) were β-lactamases producer and 47 (29.37%) were non β-lactamases producer. There were 57 (35.62%) extended spectrum β-lactamases producer, 31(19.37%) metallo β-lactamases, and 61(38.12%) AmpC producer. Highest prevalence of ESBL(76.47%), MBL(35.29%), and AmpC lactamase (64.70%) enzyme producer was observed in Acinetobacterspecies. Many of the isolates produced more than one type of β-lactamase enzymes such as 25 (15.62%) ESBL+MBL, 52 (32.5%) ESBL + AmpC, 31 (19.37%) MBL+AmpC, and 25 (15.62%) ESBL+MBL+AmpC. Conclusion: A prevalence of 35.62%, 19.37%, and 38.12% were observed for ESBL, MBL, and AmpC β-lactamases, respectively in this study. High prevalence of β-lactamases in burn wound infection emphasized the need for a continuous surveillance to detect resistant strain.

Keywords

• Key words: ESBL, MBL, AmpC, β-lactamase, antibiotic resistance.