Molecular Detection of hpmA Gene in Proteus mirabilis Isolates and its Association with Inflammatory Biomarkers among Rheumatoid Arthritis Patients

Proteus mirabilis is a Gram-negative rod-shaped bacterium most noted for its swarming motility and urease activity. It is recognized as one of considerable uropathogens. It is particularly common among patients with chronic inflammatory conditions. One of these conditions is rheumatoid arthritis, an immune-mediated inflammatory disorder that primarily affects and damages joints. This study aimed to investigate the prevalence of P. mirabilis along with its virulence gene (hpmA) in urinary tract infections and determine its association with key inflammatory biomarkers among rheumatoid arthritis patients. Eighty urine samples were collected from clinics and laboratories in Zakho city from September to December 2024. Phenotypic tests were used to identify P. mirabilis in patients’ urine, and PCR assays were performed to investigate the hpmA gene. In addition, Blood samples were analyzed for Erythrocyte sedimentation rate (ESR), Rheumatoid Factor (RF), and C- Reactive protein (CRP) from the same RA suspected patients to confirm Rheumatoid Arthritis and evaluate inflammation level. Cultural and biochemical tests identified P. mirabilis in 15 samples (18.75%). Molecular analysis revealed that all 15 isolates (100%) of P. mirabilis samples had hpmA gene. Notably, patients with P. mirabilis–positive UTIs, especially those carrying hpmA, showed elevated ESR and CRP levels. This indicates an association between hpmA-mediated pathogenicity and inflammatory responses in RA. These results suggest the importance of screening P. mirabilis and its virulence factors in RA patients with UTIs. The presence of hpmA which is responsible for hemolysin production, may be associated with increased levels of inflammation in these patients.