Characterization of Antibiotic Resistance Determinants of Extended Spectrum β-lactamases Producing Enterobacteriaceae from Cancer Patients in South India

Abstract

Patients with malignancy are highly prone to infections by Extended spectrum beta-lactamases producing Enterobacteriaceae (ESBL-PE). Knowledge on local resistance profile and resistance genes is essential to decide empirical drug. Hence, the study aims to find the resistance profile and the resistance genes of ESBL-PE from cancer patients. 172 oxyimino-cephalosporins resistant Enterobacterial isolates from clinical specimens of cancer patients were obtained. Study isolates were speciated by conventional biochemical methods. Resistance to antibiotics was detected by disc diffusion method. Phenotypic detection of ESBLs was performed as stated in CLSI guidelines. Genotypic characterization of resistance determinants of ESBL-PE was done by PCR. Among 172 Enterobacterial isolates, 151 (87.7%) were ESBL producers. E. coli (67.5%) was the major species producing ESBL enzymes followed by K. pneumoniae (27.8%). Antibiotic susceptibility pattern showed lowest resistance to imipenem 11.2%, and netilmicin 13.9%. 72% of ESBL-PE was found to be Multidrug-resistant. Among ESBL genes, blaCTX M gp-1 (83.4%) was dominant followed by blaTEM (32.4%) and blaSHV (27.8%). 36% of the isolates were found to be positive for more than one ESBL gene. High level of plasmid encoding quinolone resistance genes (64.2%) was identified in ESBL-PE. Low levels of plasmid mediated AmpC gene (15.8%) and 16S rRNA genes (9.2%) were found in ESBL-PE. The predominant ESBL encoding gene belongs to blaCTX M group 1. High proportion of ESBL-PE was found to co-harbor PMQR genes. ESBL-PE had highest sensitivity for imipenem and netilmicin.