Molecular Characterization of Multidrug Resistant Bacteria Associated with Vaginal Infection among Women of Reproductive Age Attending Some Hospitals in Bauchi Metropolis, Nigeria

Background and Aim: Vaginal infections are among the most common health conditions affecting women, and more than half of all women experience at least one episode during their lifetime. Vaginal conditions may be infectious or non-infectious and may be acute or chronic. This study aimed to determine the molecular characteristics of multidrug-resistant bacteria associated with vaginal infections among women of reproductive age attending selected hospitals in Bauchi Metropolis. Place and Duration: The study was conducted at selected hospitals in Bauchi Metropolis, Bauchi State, Nigeria (ATBUTH, Bauchi State Specialist Hospital, and Urban Maternity). Laboratory work was performed in the Microbiology Laboratory at ATBUTH. The study lasted six months (January–June 2024). Methodology: A descriptive cross-sectional study was conducted among 128 women with suspected bacterial and candidal infections. High vaginal swab (HVS) and endocervical swab (ECS) specimens were cultured on Mannitol Salt Agar, MacConkey Agar, Blood Agar, and Eosin Methylene Blue Agar. Isolates were identified using cultural, morphological, and biochemical tests. Antimicrobial susceptibility was determined using the Kirby–Bauer disk-diffusion method against 10 antibiotics, in accordance with CLSI guidelines. Multidrug resistance was defined as resistance to ≥2 classes of antibiotics. Genotypic characterisation was performed using multiplex PCR to detect the resistance genes blaCTX-M and qnrA. Data were analysed using SPSS version 24.0. Results: A total of 110 bacterial isolates were recovered from the clinical specimens. Gardnerella vaginalis was the predominant organism, accounting for 47 (42.7%) isolates, followed by Escherichia coli (28; 25.5%), Staphylococcus aureus (19; 17.3%), Klebsiella pneumoniae (8; 7.3%), Proteus mirabilis (5; 4.5%), and Atopobium vaginae (3; 2.7%). G. vaginalis showed the highest resistance to tetracycline (19.1%), whereas E. coli exhibited the highest resistance to ofloxacin and cefoxitin (42.9% each). In S. aureus, resistance was highest to cotrimoxazole (31.6%), while K. pneumoniae showed its highest reported resistance to ofloxacin (37.5%). P. mirabilis exhibited 20.0% resistance to gentamicin, amoxicillin–clavulanate, tetracycline, and oxacillin, while A. vaginae showed 33.3% resistance to several antibiotics. No vancomycin resistance was reported. These findings demonstrate variable antimicrobial resistance among the bacterial isolates. Overall, 13.6% of the bacterial isolates exhibited multidrug resistance. PCR analysis detected CTX-M and plasmid-mediated quinolone resistance genes, including qnrA, among selected multidrug-resistant isolates. Conclusion: Gardnerella vaginalis was the predominant bacterial isolate, while the occurrence of multidrug resistance and the detection of blaCTX-M and qnrA genes highlighted potential challenges in treating bacterial isolates associated with vaginal infections. Routine antimicrobial susceptibility testing and molecular surveillance are recommended to inform appropriate treatment and support antimicrobial stewardship.