Frequency of Multidrug-Resistant, Extensively Drug-Resistant, and Pandrug-Resistant Phenotypes among Clinical Isolates of Staphylococcus aureus

Background: In recent years, the widespread prevalence of Multidrug-Resistant (MDR) Staphylococcus aureus strains and the increase in the number of Extensively Drug-Resistant (XDR) and Pandrug-Resistant (PDR) phenotypes amongst S. aureus strains have become one of the greatest challenges. This study aimed to determine the incidence of MDR, XDR, and PDR phenotypes in S. aureus strains in a teaching hospital in Gorgan, Golestan province, Iran. Materials & Methods: Clinical samples of blood, urine, wound, and sputum were collected from all hospitalized patients during April to June ۲۰۱۹. S. aureus strains were identified using conventional biochemical methods, and antibiotic susceptibility assessment was performed by Kirby-Bauer disc diffusion method. Findings: A total of ۷۳ isolates were identified as S. aureus. The majority of S. aureus isolates were collected from wound specimens (۳۱ out of ۷۳). Most of the isolates were recovered from internal ward (۳۵ out of ۷۳), followed by intensive care unit (ICU) (۱۶ out of ۷۳). The highest susceptibility was observed to glycopeptides category (۱۰۰%), and the lowest susceptibility was observed to erythromycin (۵۴.۷%), followed by cefoxitin (۴۹.۳%). Out of the ۷۳ isolates, ۳۲ (۴۳.۸%) were found to be methicillin-resistant S. aureus (MRSA) isolates. Among MRSA isolates, ۹۶.۸ and ۱۲.۵% were MDR and XDR, respectively. All of the MRSA isolates, were susceptible to vancomycin. No PDR phenotype was observed among the isolates as all of them were sensitive to vancomycin (۱۰۰%). Conclusion: Based on the obtained results, the highest and lowest antibiotic resistance was observed against erythromycin and vancomycin, respectively, which is consistent with similar studies conducted in the country. Therefore, these antibiotics should not be used in the empirical therapy of S. aureus infections

Keywords:

Drug -resistance , Phenotype , Prevalence , Staphylococcus aureus