Methicillin-Resistant Coagulase-Negative Staphylococci in the Community: High Homology of SCCmec IVa between Staphylococcus epidermidis and Major Clones of Methicillin-Resistant Staphylococcus aureus

Barbier, François ; Ruppé, Etienne ; Hernandez, David ; Lebeaux, David ; Francois, Patrice ; Felix, Benjamin ; Desprez, Adeline ; Maiga, Aminata ; Woerther, Paul-Louis ; Gaillard, Kevin ; Jeanrot, Cécile ; Wolff, Michel ; Schrenzel, Jacques ; Andremont, Antoine ; Ruimy, Raymond

In: The Journal of Infectious Diseases, 2010, vol. 202, no. 2, p. 270-281

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    Background. Data on community spread of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are scarce. We assessed their potential role as a reservoir of staphylococcal cassette chromosome mec (SCCmec) IVa, the leading SCCmec subtype in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Methods. Nasal carriage of MR-CoNS was prospectively investigated in 291 adults at hospital admission. MR-CoNS were characterized by SCCmec typing, long-range polymerase chain reaction (PCR) for SCCmec IV, and multiple-locus variable-number tandem repeat analysis (MLVA) for Staphylococcus epidermidis (MRSE) strains. Three SCCmec IVa elements were fully sequenced. Results. The carriage rate of MR-CoNS was 19.2% (25.9% and 16.5% in patients with and patients without previous exposure to the health care system, respectively; P = .09). MR-CoNS strains (n=83, including 58 MRSE strains with highly heterogeneous MLVA patterns) carried SCCmec type IVa (n=9, all MRSE), other SCCmec IV subtypes (n=9, including 7 MRSE), other SCCmec types (n=15), and nontypeable SCCmec (n=50). Long-range PCR indicated structural homology between SCCmec IV in MRSE and that in MRSA. Complete sequences of SCCmec IVa from 3 MRSE strains were highly homologous to those available for CA-MRSA, including major clones USA300 and USA400. Conclusions. MR-CoNS are probably disseminated in the community, notably in subjects without previous exposure to the health care system. MRSE, the most prevalent species, may act as a reservoir of SCCmec IVa for CA-MRSA