Incidence of bla genes among uropathogenic Escherichia coli isolates from HIV and non-HIV patients in South India

Abstract

Background: Group 3a/b cephalosporins are currently being used in the treatment of UTI and urosepsis. However, Extended Spectrum Beta- Lactamase (ESBL) mediated resistance has been increasingly reported among uropathogens from HIV patients. We sought to determine the incidence of ESBL genes- blaCTX-M, blaTEM and blaSHV among E. coli isolates from HIV (with increased exposure to cephalosporins) and non-HIV antenatal patients. Methods: PCR detection of blaCTX-M, blaTEM and blaSHV were carried out among ESBL producing urinary E. coli isolates from HIV (n=57) and non- HIV antenatal patients (n=22). Fisher's exact test was employed to analyze the statistical significance of the results. Results: Overall, 31.7%, 59.5% of the E. coli isolates carried blaTEM, blaCTX-M respectively, while none harboured blaSHV. When stratified based on host group, significant difference was observed in the incidence of blaCTX-M among the isolates from HIV and non-HIV patients (70.2% vs 31.8% respectively, p = 0.0024; OR 5.042; 95% CI = 1.7441-14.5759). Nonetheless, difference in prevalence of blaTEM among the HIV and non-HIV isolates was not statistically significant (29.8% vs 36.4%, p = 0.5979). Co-occurrence of blaTEM and blaCTX-M was detected among 22.8%, 0% of the E. coli isolates from HIV and non-HIV patients respectively (OR 5.1447; 95% CI = 1.3766-19.2273). Conclusion: Our results augment the fact that frequent exposure to cephalosporins serves as the driving selection force leading to increased incidence of ESBL (blaCTX-M) mediated resistance among the E. coli isolates from HIV patients. Hence, the risk associated with antimicrobial exposure needs to be considered in therapeutic decision making.