Antimicrobial susceptibility pattern of Methicillin-resistant Staphylococcus aureus in a tertiary care Hospital

Abstract

BACKGROUND & OBJECTIVE: Methicillin-resistant Staphylococcus aureus(MRSA) has become a major therapeutic issue worldwide. The current study is designed to evaluate the antimicrobial; susceptibility pattern of MRSA strains. METHODOLOGY: This study was done in the Microbiology laboratory of Dr. Akbar Niazi Teaching Hospital, Islamabad, after ethical approval. It was a descriptive retrospective cross-sectional study in which 155 culture reports that revealed growth of Staphylococcus aureus were included from May 2021 to December 2021. The known identified strain of MRSA was used for quality control. The susceptibility pattern of MRSA strains was seen against various antibiotics. The data entry was done using SPSS version 25, and data analysis was done using frequency and percentage. RESULTS: A total of 155(11.07%) isolates of Staphylococcus aureus were obtained from 1400 culture samples. Out of these,90(58.1%) isolates were MRSA. The association was significant between MRSA and the age group of patients (p= 0.053). All the MRSA strains were sensitive to linezolid and vancomycin. The majority of the strains were sensitive to minocycline (71.1%), gentamycin (70%), and clindamycin (68.9). Only 20% of isolates were sensitive to trimethoprim/ sulfamethoxazole, 25.6% to ciprofloxacin, 31.1% to levofloxacin, and 24.4% to erythromycin. MRSA strains were sensitive to nitrofurantoin (in urine only). CONCLUSION: The frequency of Staphylococcus aureus was 11.07%, and out of these, there was a high frequency of MRSA (58.1%) in our setup. All the MRSA strains were sensitive to linezolid and vancomycin (100%). Seventy-one percent of isolates were sensitive to minocycline, 70% to gentamicin, and 68.9% to clindamycin. Only a few isolates were sensitive to macrolides (24.4%), trimethoprim-sulfamethoxazole (20%), and fluoroquinolones (25.6% to 31.1).