Evaluation of the Antibacterial Activity of Local Origanum majorana × O. vulgare Hybrid Leaf Extract against Proteus mirabilis Isolates from Urinary Tract Infections in Baghdad – Iraq

Proteus mirabilis is an important uropathogen most frequently associated with complicated urinary tract infections (UTIs) and antimicrobial resistance. This study aimed to determine the antimicrobial susceptibility and multidrug-resistance (MDR) profiles of P. mirabilis isolates recovered from UTI patients in Baghdad, Iraq, and to evaluate the in vitro antibacterial activity of the local Origanum majorana × O. vulgare Hybrid leaf extract. A total of 126 midstream urine specimens were collected from patients clinically diagnosed with UTI at three teaching hospitals in Baghdad between December 2025 and February 2026. Isolation and identification were performed using conventional microbiological methods and the VITEK 2 Compact system. Antimicrobial susceptibility was determined using VITEK 2 AST, while Multidrug-resistance (MDR) status and Multiple Antibiotic Resistance (MAR) indices were assessed. The antibacterial activity of the ethanolic Oregano leaf extract was evaluated by broth microdilution to determine the minimum inhibitory concentration (MIC)and sub-MIC. Five P. mirabilis isolates (5/126, 4.0%) were recovered, with VITEK 2 identification with probabilities of 91-99%. Resistance was highest to nitrofurantoin (100%), followed by gentamicin and trimethoprim/sulfamethoxazole (80% each). All five isolates were susceptible to piperacillin-tazobactam, ertapenem, meropenem, and amikacin. Four isolates (80%) were MDR, with MAR indices of 0.06-0.63. The Oregano leaf extract showed in vitro antibacterial activity against all five tested isolates, with MIC and sub-MIC values of 4-64 and 2-32µg/mL, respectively. These findings indicate substantial MDR among the examined isolates in this study. The Origanum majorana × O. vulgare hybrid leaf showed in vitro antibacterial activity against all five tested isolates.