Investigation of SCCmec types I-IV in clinical isolates of methicillin-resistant coagulase-negative staphylococci in Ahvaz, Southwest Iran.

Effat Abbasi Montazeri,Morteza Saki,Maryam Dastoorpoor,Azar Dokht Khosravi,Mitra Roointan,Sakineh Seyed-Mohammadi,Aram Asarehzadegan Dezfuli

doi:10.1042/bsr20200847

Abstract

Today methicillin resistant coagulase-negative staphylococci (MR-CoNS) are important in terms of causing significant nosocomial infections. Besides, MR-CoNS are confirmed as the reservoir of SCCmec elements that carry mecA (methicillin-resistant) gene. Hence, the present study was designed to evaluate the susceptibility pattern, prevalence and diversity of SCCmec types I, II, III, and IV in MR-CoNS strains. In this cross-sectional study, 44 clinical isolates of MR-CoNS were identified using the cefoxitin disc method and further confirmation by polymerase chain reaction (PCR) amplification of the mecA gene. Antimicrobial susceptibility of isolates was investigated by disc diffusion. The identification of CoNS was done by amplification and sequencing of the tuf gene. Multiplex PCR method was done for the determination of SCCmec types. In the present study, the Staphylococcus epidermidis and Staphylococcus haemolyticus were the most predominant isolates with a prevalence of 45.4%. The highest resistance rates were observed against erythromycin (84.1%) and clindamycin (75%). Multiplex PCR revealed the SCCmec type I as the predominant type in the present study. Our study showed that there was no significant relationship between the presence of different types of SCCmec elements and resistance to antibiotics. The present study highlighted a frequent prevalence of MR-CoNS harboring SCCmec type genes in Ahvaz, southwest of Iran. Thus, the molecular typing and periodical monitoring of their drug resistance pattern should be considered in national stewardship programs to designing useful antibiotic prescription strategies.

Highlights

Coagulase-negative staphylococci (CoNS) are gram-positive catalase-positive bacteria, with no ability to clot blood plasma
Various studies reported a high level of antibiotic resistance against penicillins semi-synthetic penicillins, cephalosporins, macrolides, aminoglycosides and tetracyclines has been observed in CoNS strains [6]
In the present study based on standard biochemical and microbiological tests, 90 CoNS were isolated, of which 44 isolates were confirmed as methicillin resistant CoNS (MR-CoNS) by the disc diffusion and polymerase chain reaction (PCR) of mecA gene methods

Summary

Introduction

Coagulase-negative staphylococci (CoNS) are gram-positive catalase-positive bacteria, with no ability to clot blood plasma. CoNS are resistant to different antibiotics and can cause several therapeutic problems in public health systems [3]. Several studies showed an increase in the incidence of nosocomial infections caused by methicillin resistant CoNS (MR-CoNS) strains [3]. According to the reports, during the 1990s the prevalence of MR-CoNS was higher (75–90%) than methicillin resistant S. aureus (MRSA), an observation that continues to be true today [4,5]. Various studies reported a high level of antibiotic resistance against penicillins semi-synthetic penicillins, cephalosporins, macrolides, aminoglycosides and tetracyclines has been observed in CoNS strains [6]. CoNS strains with linezolid resistance and decreased susceptibility to vancomycin have been reported recently [8]

Methods

Results

Discussion

Conclusion