Environ Exp Biol (2025) 23: 137–144

Antimicrobial resistance and the multiple antibiotic resistance index of Proteus mirabilis from diabetic foot infections and a hospital environment: insight from an Algerian diabetology ward

Abstract

Proteus mirabilis is an opportunistic pathogen commonly linked to diabetic foot infections and recognized for its persistence in healthcare environments. Its resistance to antimicrobials and ability to form biofilms contribute to treatment challenges and the spread of infections. This study compared clinical and environmental P. mirabilis isolates from an Algerian diabetology ward, analyzing their antimicrobial resistance profiles, multidrug resistance index, and biofilm-forming capacity. Over one year, 200 samples were collected 100 from diabetic foot infections and 100 from hospital surfaces. Swab samples underwent enrichment and selective culturing, with identification and confirmation via biochemical tests and an automated microbial system. Antimicrobial susceptibility was tested using disk diffusion, the multiple antibiotic resistance index was computed, and biofilm production was screened via two qualitative methods. Among 64 non-duplicate P. mirabilis isolates (39 clinical, 25 environmental), high multidrug resistance was observed, including > 80% resistance to ampicillin/amoxicillin, 68.75% to nalidixic acid, and 82.81% to cefazolin. Environmental isolates exhibited significantly higher multiple antibiotic resistance indices than clinical ones, indicating elevated resistance in hospital surfaces. All isolates formed biofilms. The prevalence of resistant, biofilm-producing P. mirabilis in both patients and the environment underscores hospitals as reservoirs for opportunistic pathogens. These results stress the importance of enhanced infection control and environmental surveillance to curb the dissemination of resistant strains in healthcare facilities.