Molecular Characterization, Antimicrobial Resistance Profiles and Histopathological Evaluation of Proteus Mirabilis Isolated from Feline Cutaneous Wounds in Baghdad, Iraq

Abstract

Background Proteus mirabilis is a non-lactose fermenting, Gram-negative rod that is a significant opportunistic pathogen in complicated skin and soft-tissue infections. Its capacity to cause wound infections in companion animals, particularly cats, raises concerns about multidrug resistance (MDR) and zoonotic transmission potential, yet data from Iraq remain scarce.

Objectives This study aims to determine the prevalence, phenotypic characteristics, multidrug resistance (MDR) profiles, virulence-associated ureR gene and histopathological effects of P. mirabilis isolated from cutaneous wounds of owned and stray cats.

Methods A total of 100 swabs (50 owned and 50 stray cats) collected from feline wounds. P. mirabilis isolates were identified by standard biochemical techniques and confirmed using the VITEK 2 Compact system. PCR analysis targeting the ureR virulence gene (225 bp) was performed on all confirmed isolates. Antimicrobial susceptibility testing was conducted to establish MDR profiles. Pathogenicity was assessed using a rabbit wound infection model. A total of 15 rabbits were randomly divided into three groups (n=5 per group): G1 (non-infected control), G2 (infected with owned cat isolates), and G3 (infected with stray cat isolates). Tissue sections were processed with haematoxylin and eosin staining for histopathological evaluation.

Results P. mirabilis was isolated from 13% of samples, with a higher Prevalence in stray (16%) than owned cats (10%), particularly associated with purulent abscesses. All 13 confirmed isolates were positive for the ureR virulence gene (225 bp). Antimicrobial susceptibility testing showed an MDR profile with resistance to ampicillin, cephalosporins, aminoglycosides and fluoroquinolones while all the isolates were still sensitive against carbapenems. Histopathological evaluations revealed that G3 induced more severe tissue damage than G2, including extensive inflammatory infiltration around necrotic areas, sluggish re-epithelialization, loss of skin appendages, irregular angiogenesis and abscess formation.

Conclusion this study provides evidence of MDR P. mirabilis virulence potential within feline wounds and indicates that isolates from stray cats may be more pathogenic compared to those from owned cats. As a result, a molecular diagnosis, histopathological field and culture-guided antimicrobial therapy are required to effective management of MDR wound infections in veterinary practice.