Studing the frequency of methicillin-resistant staphylococci by phenotypic and molecular methods among patients in some hospitals of Rasht

Meticillin resistant Staphylococcus aureus (MRSA) has become one of the major public-health concerns in recent years due to resistance to antimicrobial drugs and agents. This Study aims to diagnose of MRSA isolates by molecular and phenotypic methods and to detect of the antibiotic resistance pattern in MRSA strains in clinical patient samples in Rasht.

This cross-sectional (descriptive-analytical) study was conducted from April to September 2016. 76 isolates of Staphylococcus were collected from some hospitals in Rasht and was characterized by varius biochemical tests of Staphylococcus aureus species. A disc diffusion method was performed to identify MRSA strains. The antibiotic resistance pattern of isolates was done using disc diffusion method against six antibiotics based on Clinical and Laboratory Standards Institute (CLSI) protocol. Then, Polymerase Chain Reaction (PCR) was performed with specific primers to mecA gene. Also, sequencing was done in mecA positive PCR products. Data were analyzed using SPSS 23 software. 

The results of this study, showed that 69 (90.8%) out of 76 isolates of Staphylococcus were S.aureus. The rate of MRSA strains in the phenotypic(disk diffusion) and PCR methods were 71% and 62.3%, respectively. The S. aureus isolates exhibited the most sensitivity and resistance to gentamicin(72.46%) and bacitracin(82.6%), respectively. No significant correlation was found between MRSA isolates and type of sample(P>0.05).

The findings showed that the presence of MRSA strains were remarkable in the hospital samples in Rasht because of the overuse of antibiotics for the treatment of diseases.