Investigating the antibiotic resistance pattern of MRSA isolates from blood and wound samples of patients admitted in a number of Tehran university of medical sciences hospitals: a brief report

Considering the frequency of MRSA strains in hospitals and medical centers as well as in different communities, it seems necessary and important to observe the use of appropriate drugs in order to reduce antibiotic resistance and reduce the economic costs of treatment. This study aimed to investigate the antibiotic resistance pattern of MRSA isolated from blood and wound samples of patients. The study patients were hospitalized in different departments in a number of Tehran University of Medical Sciences hospitals.

In this descriptive cross-sectional study from September 2021 to February 2022, the blood and wound samples of the patients were collected and referred to laboratory. Staphylococcus aureus had identified by phenotypic and biotypic tests. MRSA isolates were screened by showing resistance to Cefoxitin by disc diffusion method and finally confirmed by examining the mecA gene by PCR. The microbial resistance pattern of MRSA was also measured by disk diffusion method and resistance to Vancomycin was confirmed by E.test.

41 isolates from 87 Staphylococcus aureus samples were confirmed as MRSA by present the mecA gene. The mecA gene was detected in all MRSA by PCR method. The antibiotic resistance pattern showed the highest sensitivity to Vancomycin and Linezolid with 100% sensitivity and the highest resistance to three antibiotics Erythromycin, Ceftriaxone and Cloxacillin with 97.57%by disk diffusion method. The most MRSA strains were isolated from the ICU department with 13 cases and the least MRSA strains were isolated from the two NICU and pediatric departments with one case.The majority of the population infected with MRSA belonged to the age group of 40-65 years.

The prevalence of microbial resistance with high dispersion was obtained among MRSA strains isolated from clinical samples; which indicates a significant increase in resistant strains and requires a quick and timely diagnosis to prescribe the appropriate antibiotic.