SCCmec and mecA in methicillin resistant staphylococci, a highly diversified element with new mutations in mecA

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Ferhat Djoudi and Dalila Benremila

University of Bejaia, Algeria

: J Virol Antivir Res

Abstract

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Genetic mechanisms of methicillin resistance are still relevant in staphylococci. The aim of this study is to assess the possible exchanges of staphylococcal cassette chromosome mec (SCCmec) between isolates of methicillin-resistant staphylococci (MRS) and to check for known or new mutations in mecA DNA. A total of 35 MRS non-repetitive isolates were recovered, including 20 S. haemolyticus, 7 S. aureus, 4 S. sciuri, 2 S. saprophyticus and one isolate each of S. xylosus and S. lentus. Only 16 of the 35 strains were assigned to known SCCmec types: 7-SCCmec VII, 6-SCCmec IV and 3-SCCmec III, with possible horizontal transfer of the SCCmec VII from methicillin-resistant S. haemolyticus to methicillin-susceptible S. aureus. mecA genes sequencing in ten selected isolates allowed description of nine punctual mutations, seven reported for the first time. The most frequent mutation was G246E, identified in isolates of methicillin-resistant S. aureus, S. sciuri, S. saprophyticus and S. lentus. These results emphasized the high degree of genetic diversity of SCCmec element in methicillin-resistant staphylococci and describe new missense mutations in mecA, which might be important in understanding the evolution of methicillin and new β-lactams resistance.

Biography

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