Asymptomatic bacteriuria as a reservoir for carbapenemase-producing Enterobacterales: A molecular epidemiological study of diabetic postmenopausal women in Tripoli, Libya.

INTRODUCTION: Asymptomatic bacteriuria (ASB) in diabetic postmenopausal women represents a critical yet under-monitored reservoir for multidrug-resistant (MDR) uropathogens. In regions with high antibiotic selection pressure, like Libya, the emergence of carbapenem-resistant Enterobacterales (CRE) threatens the efficacy of last-resort therapeutic options. This study aimed to characterize the phenotypic and genotypic resistance landscapes of Escherichia coli and Klebsiella pneumoniae isolates obtained from this specific risk population.

METHODS: A cross-sectional study was conducted involving 400 postmenopausal women (251 diabetic and 149 non-diabetic controls) in Tripoli, Libya. Clinical isolates were identified and tested for antibiotic susceptibility using the BD Phoenix™ M50 automated system. Optimized multiplex PCR protocols were developed to detect five major carbapenemase families and five blaCTX-M phylogenetic groups.

RESULTS: The prevalence of ASB within the diabetic cohort was 27.9% (70/251). Notably, these cases accounted for 79.5% (70/88) of all uropathogens recovered throughout the study. Phenotypic carbapenem resistance was alarmingly high in K. pneumoniae (36.0%). Molecular analysis restricted to the 18 selected multidrug-resistant (MDR) isolates confirmed blaKPC and blaIMP as the primary genetic drivers. In contrast, E. coli isolates were largely driven by Extended-Spectrum Beta-Lactamase (ESBL) production, specifically blaCTX-M Group 1 and Group 9. Amikacin demonstrated 100% susceptibility against E. coli, representing the most effective non-carbapenem option.

DISCUSSION: Our findings reveal that diabetic postmenopausal women in Libya serve as a significant community reservoir for high-risk MDR clones, including KPC- and IMP-producing K. pneumoniae. The strong correlation between observed genotypes and resistant phenotypes underscores the necessity for routine molecular surveillance. These results emphasize the critical role of targeted antimicrobial stewardship and epidemiological monitoring, even in asymptomatic populations, to prevent the 'silent' dissemination of carbapenemase-producing organisms within the community.