Reemergence of Gentamicin-Susceptible Strains of Methicillin-Resistant Staphylococcus aureus in France: a Phylogenetic Approach

The reemergence of gentamicin-susceptible (Gen(s)) methicillin-resistant Staphylococcus aureus (MRSA) isolates in France between 1992 and 1996 was investigated using a phylogenetic approach (multiprimer randomly amplified polymorphic DNA typing). Eighty-six percent (65 of 85) of the French strains were grouped into one phylogenetic cluster within which all but one Gen(s) strain were grouped into a subcluster. Thus, the reemergence of Gen(s) MRSA strains in France was likely due to the spread of one specific clone which belonged to a cluster comprising most French gentamicin-resistant (Gen(r)) strains. This suggests that the Gen(s) clone has emerged from a Gen(r) strain of this cluster.