Research Article Open access Peer reviewed

Molecular Identification of blaCTX-M producing clinical isolates of Escherichia coli

Authors

Muzammil Hussain Shahidhttps://orcid.org/0009-0004-7816-6454, Muhammad Usman Qamar, Muhammad Hidayat Rasoolhttps://orcid.org/0000-0002-6324-1798, Muhammad Atif Nisar

Government College University, Faisalabad, Pakistan

Received
Published
DOI https://doi.org/10.55006/biolsciences.2023.3303 Citation Biological Sciences, Vol. 3 No. 3 (2023), 461-468

Abstract

Extended spectrum-β-lactamases (ESBLs) producing E. coli is a major cause of urinary tract infections (UTI) in the world. Present study indicates that there is high prevalence of multidrug resistant containing blaCTX-M variants of E.coli in UTI. Purpose of this study was to find out the frequency of different ESBL types i.e., blaCTX-M-1, blaCTX-M-10 and blaCTX-M-14 among clinical isolates of Escherichia coli which is the causative agent of more than 80% of urinary tract infections. In this study, 100 isolates were taken from UTI patients and their susceptibility pattern was studied. Isolates were sub-cultured on MacConkey and blood agar aseptically. E. coli were initially identified based on their colony morphology and cultural characteristics and confirmed by API 20E. Antimicrobial resistance profile was determined by using Kirby-Baur disk diffusion method. Phenotypic detection of ESBL producing clinical isolates of E. coli was confirmed by double disk diffusion method according to CLSI 2015 guidelines. Out of 100 isolates, 64 were ESBL producers. Most of the E. coli showed 100 % resistance to first generation cephalosporin antibiotics i.e., cephalexin and cephradine, 94% to nalidixic acid and 56% to co-trimoxazole while most resistant drugs were carbapenems imipenem (100%) and meropenem (100%). Molecular characterization showed that among 64% ESBLs producing isolates of E. coli, different CTX-M variants were identified.CTX-M-1 producing E. coli isolate was more prevalent ESBL (44%) followed by CTX-M-10 (23%) and CTX-M-14 (14%). E. coli harbouring CTX-M-1 enzyme were completely resistant to cephalexin and cefradine antibiotics that belong to first generation cephalosporin antibiotics. They showed 100% sensitivity to carbapenem drugs (imipenem and meropenem). All isolates having CTX-M-1 enzyme showed high resistance than sensitivity to all the drugs. E. coli possessing CTX-M-10 enzyme showed strong hydrolytic activity and complete resistance to cefalexin and cefradine drugs while nitrofurantoin was the most effective drug. In fact, most of the E. coli producing CTX-M-10 enzyme was more resistant and less susceptible to the antibiotics. Isolates harbouring CTX-M-14 enzyme showed 100% resistance to most of the drugs and very few were effective. CTX-M-14 are the enzymes that display strong hydrolytic activity against many antibiotics of different classes. This study concluded a higher prevalence of ESBLs producing E. coli with predominant CTX-M-1enzyme. Multi drug resistant and CTX-M ESBLs production was major contributing factor to higher urinary tract infections.

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