Characteristics of community-acquired methicillin-resistant Staphylococcus aureus associated with wound infections in Tehran, Iran: High prevalence of PVL+ t008 and the emergence of new spa types t657, t5348, and t437 in Iran

Abstract

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a major concern in Iran. The present study aimed to determine characteristics and the distribution of spa types of CA-MRSA strain isolated in wound infections. We investigated 120 CA-MRSA isolates by spa typing, virulence gene detected and in vitro antimicrobial susceptibility was assayed. Of the 120 CA-MRSA clinical isolates, 89.1% were confirmed as multidrug resistance (MDR). Virulence genes pvl, tst, eta, and etb were detected in 33.3%, 12.5%, 4.2%, and 1.7% of the isolates, respectively. All strains were distributed across 14 distinct spa types including t008 (21.7%), t790 (11.7%), t030 (9.1%), t044 (8.3%), t021 (7.5%), t019 (6.7%), t015 (6.7%), t852 (5.8%), t091 (5%), t437 (4.2%), t084 (4.2%), t005 (3.3%), t5348 (3.3%) and t657 (2.5%). PVL-carrying strains belonged to t008 (21.6%), t044 (5%), t021 (1.7%), (t019 1.7%), t005 (0.8%) and t852 (2.5%). t008 spa type was found to be associated with high-level mupirocin-resistant phenotype while t790 and t084 spa type were related to high-level mupirocin-resistant phenotype. Importantly, spa types t030 (n = 2) and t790 (n = 1) displayed resistance to fusidic acid. Mupirocin resistance was found for 20% of isolates which of these, 6.7% and 13.3% demonstrated high- and low-level mupirocin resistance phenotype respectively. Out of 120 strains examined, MS, iMLSB and cMLSB phenotypes were detected in 16 (13.3%), 20 (16.7%) and 39 (32.5%) isolates, respectively. The present findings clarified a genetic diversity of CA-MRSA strains in our area with the majority of t008 spa type highlighting the need for more effective surveillance/infection control strategies to keep track and prevention of the emerging spa types.