Distribution of staphylococcal cassette chromosome types among methicillin-resistant coagulase negative staphylococci in central Iran.

BACKGROUND AND OBJECTIVES

Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are important nosocomial pathogens. They may serve as a reservoir of SCC, the genomic island encoding amongst other methicillin resistance. This study was designed to determine the distribution of different SCC types from MR-CoNS isolated from clinical specimens in a tertiary hospital in central Iran, having high frequency of nosocomial methicillin-resistant staphylococcal infections.

MATERIALS AND METHODS

We evaluated isolates from patients attending the Vali-Asr Hospital located in the center of Iran, from February to December 2012. Multiplex PCR was performed for SCC typing. For isolates in which SCC could not be typed directly, additional and complex analyses were performed.

RESULTS

Totally, 70 MR-CoNS isolates, comprising of 47 strains (67%), 10 (14.3%), 9 (13%) and 4 (5.7%) were identified. Thirty-nine were characterized as type IVa 19 (27%), type III 11 (16%), type II 7 (10%) and type V 2 (3%). Only 20 isolates (28.6%) carried the ccr complex, while the current methods could not characterize the 11 remaining isolates.

CONCLUSION

A high level of SCC genetic diversity was found among MR-CoNS isolates. MR-CoNS may act as a reservoir of SCC IV for MRSA. This issue should be taken into consideration seriously.