Molecular detection of tetracycline resistance genes in association with efflux pump mechanism in uropathogenic escherichia coli (UPEC) isolate

Lee, Shuet Yi (2022) Molecular detection of tetracycline resistance genes in association with efflux pump mechanism in uropathogenic escherichia coli (UPEC) isolate. Final Year Project, UTAR.

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Abstract

Uropathogenic E. coli (UPEC) is the most common causative agent of urinary tract infections (UTIs). In recent years, UPEC strains were reported to show increase rate in multidrug resistance (MDR), especially to tetracycline class. The rationale behind the continued emergence of antimicrobial resistance is the dissemination of tetracycline efflux genes among bacterial strains. Thus, the current study was conducted to detect the prevalence of tetA and tetB genes in correlation with efflux pump resistance mechanisms among the UPEC isolates through molecular screening. A total of 60 UPEC isolates retrieved from Hospital Raja Permaisuri Bainun, Ipoh were subjected to antimicrobial susceptibility testing, followed by molecular detection tetA and tetB genes through duplex PCR assay. UPEC isolates were predominantly collected from females (73.33%) and working age groups (53.33%). UPEC isolates were found to be most resistant to ampicillin (71.67%) and tetracycline (51.67%), but highly susceptible to imipenem (0.00%) and minocycline (1.67%). Among 60 UPEC isolates, tetA positive isolates (n = 26, 41.67%) were detected to be higher as compared to tetB positive isolates (n = 7, 11.67%), while only one isolate showed co-existence of both tetA and tetB genes (1.67%). Despite showing negative tet gene association with demographic profiles of patients (p-values > 0.050), the tet efflux genes significantly correlate with the resistance profiles of tetracycline antibiotic class. The tetracycline resistance traits showed statistically significant positive association with both tetA (p = 0.000) and tetB (p = 0.029), whereas minocycline resistance profiles only associate positively with tetB (p = 0.010). All tetracycline-resistant isolates harboured at least one tet efflux gene. Meanwhile, only one out of 60 UPEC samples showed minocycline resistance, which was screened positive for tetB gene. In addition, tetA gene was discovered to positively associate with resistance profiles of nalidixic acid (p = 0.020), trimethoprim-sulfamethoxazole (p = 0.001) and ampicillin (p = 0.000).

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