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Characterization of virulence factors and antibiotic resistance pattern of uropathogenic Escherichia coli strains in a tertiary care center

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Oct 21, 2022 version files 29.85 KB

Abstract

Background: Urinary tract infections (UTIs) are the most prevalent bacterial infection in humans. The uropathogenic E. coli (UPEC) express a wide range of virulence factors that contribute to their pathogenicity. The emergence of Multidrug resistance(MDR)-associated UTI is increasing off late. Hence this study was undertaken to monitor the distribution of virulence factors among UPEC strains and to note the antibiogram, outcome and type of associated UTI.

Methods: A prospective cross-sectional time-bound study of 6 months was done on clinically significant urinary isolates of Escherichia coli. Detection of haemolysin production and serum resistance was done by phenotypic methods. Genotypic characterization of the virulence genes (papC, iutA, hlyA, cnf1) was done by multiplex PCR. Demographic data, clinical history, antibiogram and type of UTI were collected from clinical case records.

Results: 75 E. coli isolates from patients with suspected urinary tract infections were included. Females had a higher preponderance of UTI (66.7%).93% of the patients were adults and the remaining 7% were from the paediatric population.  24 (32%) isolates showed haemolysis by plate haemolysis method, and all 75 (100%) isolates were serum resistant. Out of 75 isolates, 65 were positive for at least one of the four targeted genes, while the remaining 10 isolates were negative for all 4 genes. Multidrug resistance was found in 40 (53.3%) isolates. 97.4% of the UTI cases had a favourable clinical outcome at discharge. Mortality due to urosepsis was 2.6%.

Conclusion: The association of hemolysin production with resistance to imipenem and norfloxacin in UPEC strains was significant. The presence of the hlyA gene is positively associated with ceftazidime resistance. Nitrofurantoin, piperacillin tazobactam and cefaperazone sulbactam maybe suitable candidates for empirical therapy of UTIs. Drugs like aminoglycosides, carbapenems and fosfomycin may be used as reserve drugs in the treatment of MDR-UTI. However, inappropriate usage can gradually increase antibiotic resistance. Hence, proper selection of antibiotics in hospitals taking into account the local antibiogram is needed to reduce the emergence of antibiotic resistance.