A cross-sectional study on the prevalence of multidrug-resistant clinical isolates of Proteus species in Northern Iran.

Introduction: Multidrug-resistant (MDR) bacteria like Proteus species have led to more prolonged hospitalizations, fewer care choices, higher treatment costs, and even death. The present study aims to evaluate the prevalence of MDR Proteus species in clinical samples and to suggest the best therapeutic options for the MDR Proteus species.

Methodology: Clinical samples were collected randomly from five hospitals in Golestan Province, Iran, from February 2017 to July 2019. Disk diffusion on Mueller-Hinton agar plates were used to perform antibiotic susceptibility testing (ASTs). By using a double-disc synergy test (DDST), isolates resistant to one of the third-generation cephalosporins were examined for phenotypic extended-spectrum β-lactamase (ESBL) development. A combined double disk synergy test (CDDST) was used to identify MBL-producing isolates.

Results: 61 Proteus isolates, including P. Mirabilis 44/61 (77.04%), P. vulgaris 7/61 (11.47%), P. hauseri 5/61 (8.19%), and P. penneri 2/61 (3.27%) were collected. Most of the isolates were obtained from urine samples. P. hauseri isolates were more frequent in females. Resistance to tetracycline and nitrofurantoin antibiotics was observed in most Proteus isolates. P. penneri isolates were all resistant to antibiotics. ESBL production was observed in five ceftazidime-resistant isolates (p < 0.05).

Conclusions: Cefepime and imipenem were found to have the lowest occurrence of antibiotic resistance among Proteus species, confirming that cefepime and imipenem can be used to treat Proteus infections.