Phenotypic Detection of Metallo-β-Lactamase-Producing Uropathogens Among First-Year Students of the Federal University of Agriculture, Abeokuta

Abstract

Background: Metallo-β-lactamase (MBL)-producing Gram-negative bacteria are important antimicrobial-resistant pathogens because these enzymes can hydrolyze β-lactam antibiotics, including carbapenems. However, information on the occurrence of MBL-producing uropathogens in apparently healthy young populations remains limited. Objectives: This study investigated the occurrence of metallo-β-lactamase-producing Gram-negative uropathogens among newly admitted students of the Federal University of Agriculture, Abeokuta, Nigeria. Methods: A descriptive cross-sectional study was conducted. After informed consent was obtained and eligibility screening was completed, 100 participants were consecutively recruited. Midstream urine specimens were aseptically collected and cultured on cystine lactose electrolyte-deficient agar and MacConkey agar, and bacterial isolates were identified using conventional microbiological and biochemical techniques. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Multidrug-resistant (MDR) isolates were screened for carbapenemase production using the Modified Hodge Test, and MBL production was confirmed using an EDTA-based combined disc diffusion test. Results: A total of 100 participants were enrolled, of whom 55% were male and 45% were female. Most participants were aged 16 - 20 years (48%), followed by 21 - 25 years (37%) and 26 - 30 years (15%). A total of 120 Gram-negative bacterial isolates were recovered, indicating that some samples yielded more than one isolate. The predominant isolate was Escherichia coli (33%), followed by Klebsiella pneumoniae (27%), Pseudomonas spp. (17%), Proteus vulgaris (12%), and Enterobacter spp. (11%). More isolates were recovered from male than from female participants. Among the 120 Gram-negative isolates, 47 (39.2%) were multidrug resistant, with K. pneumoniae (36.1%) and E. coli (34.0%) accounting for the highest proportions of MDR isolates. Of the 47 MDR isolates, 18 (38.3%) were confirmed as MBL producers using phenotypic methods. Conclusions: The study demonstrated the presence of MBL-producing Gram-negative uropathogens in the urine of asymptomatic first-year students at the study site.