Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) strains are on the rise leading to severe morbidity and mortality in ICU patients worldwide including Saudi Arabia. In the present study, the prevalence, gender distribution and antimicrobial resistance pattern of this gram-positive nosocomial bacterial pathogen were explored. The strains were isolated from 6840 sampled patients at King Fahd Hospital, Madinah, KSA. Clinical sources were screened for MRSA strains during a period of 14 months and it was observed that MRSA represented only 5% of the total isolated positive samples. Exactly 237 MRSA strains were isolated from male patients and hence showed predominance over female samples, except in case of two sources (catheter tips and pus sample). Almost equal percentages of MRSA strains were recovered from wound swabs (124 strains) and sputum (120 strains) samples while 37 strains were recovered from nasal swabs. Collectively these three sources contributed majorly 84.7%. Antimicrobial sensitivity to conventional drugs was studied and the percentage resistance was in the following order: amoxicillin (99.5 %) ˃ daptomycin, (98.8 %) ˃ linezolid (98.0 %) ˃ clindamycin (91.3 %) ˃ erythromycin (90.8 %). ˃ cotrimoxazole (84.4 %) ˃ vancomycin (37.2 %). Vancomycin showed significant sensitivity of 62.8 % suggesting that this drug is a better option for effective treatment. After a high trend of MRSA infection (51%) during summer, a significant decrease (20.7%) was observed during autumn which coincides with the annual Hajj season when special infection control provisions are taken. After Hajj season is over, infections decrease further to 18.5% during winter and 9.8% in spring. The present study is significant in being a step towards generation of national data on the prevalence of antimicrobial resistance patterns of MRSA.

Key words: Methicillin-resistant Staphylococcus aureus, gram positive bacteria, antimicrobial susceptibility pattern, antibiotic resistance, methicillin resistance.