Screening of Extended Spectrum Beta-Lactamase Producing Bacteria in Clinical Liquid Waste

Abstract

Admixture of Clinical Liquid Waste (CLW) discharging into Ecological Water Bodies (EWB) causes significant pollution with resistant bacteria. The issue is significant in Bangladesh where CLW management is at early stage of development. Extended-Spectrum ?-Lactamase (ESBL) producing bacteria confer resistance to Broad Spectrum ?-Lactam Antibiotics (BSBLA) which has become a global concern now. The aim of this study was to characterise and assess the occurrence of ESBL producing bacteria in CLW of Bangladesh. Three CLW samples were collected from two leading hospitals in Dhaka City, Bangladesh in the year 2012. A total 166 isolates were retrieved and screened for ESBL production by the Double Disk Diffusion Synergy Test (DDST). Isolates with ESBL phenotype were further characterized by antibiotic susceptibility testing, PCR and sequencing of ?-lactamase genes. A total of 30 ESBL producers with Multi Drug Resistant (MDR) properties were isolated. Gene specific PCR against blaTEM, blaCTX-M, and blaSHV detected CTX-M as major ESBL genotype (83%) followed by occurrence of TEM-genotypes (40%). Prevalence of SHV was low in CLW samples (3%). More than 20% of CLW -ESBL isolates possessed both the TEM and CTX-M genotypes. The predominant ESBL isolates were phylogenetically identified as Escherichia spp. Seventy seven percent followed by Citrobacter spp. (17%), Klebsiella spp. (3%), and Yokenella spp. (3%). This investigation demonstrates that CLW possesses ESBL producing MDR bacteria which might act as potential threat to disseminate resistant determinants in the surrounding environment.