Molecular Detection of Esp and qnrA Genes in Biofilm-Producing Multidrug-Resistant Proteus mirabilis from Catheter-Associated Urinary Tract Infections in Bauchi Metropolis, Nigeria

Background and Aims: Catheter-associated urinary tract infections may involve multidrug-resistant (MDR) Proteus mirabilis capable of biofilm formation. Molecular data on such isolates in Bauchi Metropolis, Nigeria, are limited. This study investigated antimicrobial resistance, biofilm formation and PCR detection of esp-targeted and qnrA amplicons in P. mirabilis from catheterised patients. Methods: In this cross-sectional, laboratory-based study, 227 urine specimens were collected from catheterised inpatients at Abubakar Tafawa Balewa University Teaching Hospital (n = 130) and Specialist Hospital Bauchi (n = 97) between January and July 2025. Isolates were identified using culture characteristics, microscopy and biochemical tests. Disc diffusion was used for antimicrobial susceptibility testing, and the tube method was used to assess biofilm formation. Five MDR, biofilm-producing isolates underwent conventional PCR. Results: Among 173 microbial isolates, 12 (6.9%) were P. mirabilis (six each from ATBUTH and SHB). A higher proportion of isolates was recovered from female patients (58.3%) and from patients aged ≥60 years (83.3%), with more isolates recovered following longer durations of catheterisation (≥30 days: 33.3%). The isolates showed high resistance to amoxicillin (66.7-100%), cefotaxime (83.3-100%), ceftazidime (66.7-83.3%), cotrimoxazole (66.7-100%), and fluoroquinolones (66.6-100%) based on hospital-specific denominators (ATBUTH n=6, SHB n=6). Among the five biofilm-producing MDR isolates subjected to molecular analysis, Esp was detected in 5/5 (100%) and qnrA in 4/5 (80.0%). These results apply only to the tested subset and cannot be generalised to all 12 P. mirabilis isolates Conclusion: Multidrug-resistant, biofilm-producing P. mirabilis with Esp-targeted and qnrA amplicons were detected among catheterised patients in Bauchi. These findings underscore the need for strengthened catheter care, antimicrobial stewardship and continued surveillance to control CAUTIs.