Phenotypic Detection of Extended-Spectrum β-Lactamase and Antimicrobial Resistance Patterns in Multidrug-Resistant Uropathogenic Enterobacterales at a Tertiary-Care Hospital in Bangladesh

Pratik Biswas, Sanjida Khondakar Setu, Abu Naser Ibne Sattar, Avik Dey Avi Department of Microbiology and Immunology, Bangladesh Medical University, Dhaka, BangladeshCorrespondence: Pratik Biswas, Email [email protected]: Urinary tract infections (UTIs) are common bacterial infections worldwide, and increasing multidrug resistance (MDR) and extended-spectrum β-lactamase (ESBL) production among uropathogenic Enterobacterales have increasingly limited empirical and targeted treatment options, particularly in low- and middle-income countries.Methods: This laboratory-based cross-sectional study was conducted at Bangladesh Medical University, Dhaka, Bangladesh. Eligible MDR uropathogenic Enterobacterales isolates from routine diagnostic urine specimens were collected and tested after Institutional Review Board approval on 13 July 2025. Urine specimens were obtained as part of standard hospital diagnostic procedures from patients with suspected UTI. A total of 122 MDR isolates were included. Bacterial identification was performed using conventional biochemical methods. Antimicrobial susceptibility testing was performed by Kirby–Bauer disk diffusion following CLSI 2024 guidelines, and phenotypic ESBL production was detected by the double-disc synergy test. MDR classification was based on the complete routine antimicrobial susceptibility testing record, including amikacin and gentamicin. Descriptive statistics and exact binomial 95% confidence intervals (CIs) were calculated.Results: Among these 122 MDR isolates, Escherichia coli was predominant (81/122, 66.4%), followed by Klebsiella spp. (38/122, 31.1%) and Proteus spp. (3/122, 2.5%). Resistance was highest to nalidixic acid (122/122, 100.0%), ceftazidime (117/122, 95.9%), ceftriaxone (116/122, 95.1%), cefepime (113/122, 92.6%), ciprofloxacin (106/122, 86.9%), and meropenem (27/122, 22.1%). Phenotypic ESBL production was identified in 59/122 isolates (48.4%; 95% CI: 39.2– 57.6%). DDST-positive isolates showed descriptively higher cephalosporin resistance than DDST-negative isolates, while ciprofloxacin resistance was similarly high in both groups. In this dataset, meropenem resistance was observed only among DDST-negative isolates.Conclusion: Among MDR uropathogenic Enterobacterales from a single tertiary-care hospital in Bangladesh, ciprofloxacin and cephalosporin resistance and phenotypic ESBL production were high. Findings support routine ESBL screening, local susceptibility surveillance, and antimicrobial stewardship, but should be interpreted within the study’s MDR-only, single-center scope.Keywords: urinary tract infection, antimicrobial resistance, ESBL, multidrug-resistant Enterobacterales, double-disc synergy test, Bangladesh