Patterns of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated at a tertiary care hospital

Abstract

Background: The current study was aimed to investigate the patterns of Methicillin-resistant Staphylococcus aureus (MRSA) isolates and their antibiotic susceptibility in Oman with a special focus on determining the changing resistance patterns. Materials and Methods: The current study was a retrospective cross-sectional study, conducted at a referral hospital in Oman. The socio-demographic characteristics and the microbiological data of MRSA strains isolated between January 2015 and December 2018 were reviewed. Descriptive statistics were presented as frequencies and percentages. Results: In total, 1190 MRSA isolates from clinical specimens were studied. Infection was predominant among males (59%). There was an increasing trend of MRSA infection (19.2%–28.5%) from 2015 to 2018. The frequency of infection was less among elderly as compared to other age groups. Majority (58.7%) of MRSA was recovered from pus and wound swabs. The overall resistance to the tested antibiotics was as follows; ciprofloxacin (30.2%), erythromycin (27.1%), clindamycin (21.8%), gentamicin (10.7%), trimethoprim-sulfamethoxazole (5.2%), linezolid (0.3%), and vancomycin (0.2%). Furthermore, a significant increase in resistance to antibiotics such as ciprofloxacin (from 16.8% to 37.1%), erythromycin (from 13.4% to 27.7%), gentamicin (5.2% to 16.1%), clindamycin (from 11.5% to 26.6%), and trimethoprim-sulfamethoxazole (from 1.8% to 7.2%) over time from 2015 to 2018 was observed. Conclusions: The present study revealed a relatively high frequency of MRSA infection and changes in their antibiotic-resistance patterns to some commonly used antibiotics over time in Sohar Hospital. Optimized antibiotic prescription through targeted stewardship interventions to preserve formulary antibiotics that still maintain their effectiveness and updating existing infection control practices is crucial.