Molecular characterization of methicillin-resistant Staphylococcus aureus: characterization of major clones and emergence of epidemic clones of sequence type (ST) 36 and ST 121 in Tehran, Iran

• Published in: FEMS microbiology letters Vol. 362; no. 8; p. fnv043
• Main Authors: Ohadian Moghadam, Solmaz, Pourmand, Mohammad Reza, Mahmoudi, Mahmood, Sadighian, Hooman
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.04.2015
• Subjects: Bacterial Proteins - genetics; Bacterial Toxins - genetics; Chromosomes; Cluster analysis; DNA, Bacterial - genetics; Drug resistance; Epidemics; Epidemiology; Exotoxins - genetics; Humans; Iran; Leukocidin; Leukocidins - genetics; Methicillin; Methicillin Resistance - genetics; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - pathogenicity; Microbial Sensitivity Tests; Microbiology; Molecular Epidemiology; Molecular structure; Molecular Typing; Multilocus Sequence Typing; Multiplex Polymerase Chain Reaction; Penicillin-Binding Proteins; Prevalence; Spas; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology; Staphylococcus infections; Virulence Factors - genetics; Tehran Iran; Iran; Panton-Valentine leukocidin; multilocus sequence typing; methicillin-resistant; antibacterial drug resistance; molecular typing; methicillin-resistant Staphylococcus aureus
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnv043

Information about the molecular structure of MRSA strains provides significant insights into the epidemiology of this important pathogen. To investigate the molecular characteristics of MRSA isolates, MRSA isolates were subjected to molecular typing by means of spa typing, multilocus sequence typing, Staphylococcal Cassette Chromosome mec (SCCmec) grouping and to phenotypic antimicrobial susceptibility testing by means of disk diffusion assay. Then the presence of pvl genes was evaluated. Cluster analysis by eBURSTv3 showed that MRSA isolates belonged to two major clonal complexes (CC); CC8 (ST239, ST585, ST2732, ST1294) and CC30 (ST30, ST36, ST1163) and four singletons. Subsequent analysis of MRSA isolates revealed that the most prevalent SCCmec type was type III (55.8%) followed by type IV (34.9%) and type II (2.3%). Totally 11 different spa types were discriminated among which types t037 and t030 were predominant. The prevalence of Panton-Valentine leukocidin (PVL)-positive MRSA strains was high (20%), which is a matter of great concern, because the PVL is frequently associated with severe and recurrent SSTIs. ST239-III- t037 represented the most predominant MRSA clone. The presence of sequence type (ST) 36 and ST 121 are being reported for the first time in Iran. Molecular characterization of MRSA.