Methicillin-resistant, quinupristin-dalfopristin-resistant Staphylococcus aureus with reduced sensitivity to glycopeptides

Of 3,052 Staphylococcus aureus strains collected by the European SENTRY sur veillance study, 35 were found to be nonsusceptible to quinupristin-dalfopr istin (MIC of greater than or equal to2 mg/liter). These isolates originate d from four hospitals in France and one in Spain. In isolates from two Pari sian hospitals exhibiting the same Sinal macrorestriction pattern, streptog ramin resistance was based on vatA and vgbA. One isolate from a hospital in Lyon and 22 from a hospital in Lille were of the vatB vgaB streptogramin A resistance genotype and possessed ermA and/or ermC. As deduced from the lo ss of either streptogramin A or streptogramin B resistance determinants in particular isolates, resistance to quinupristin-dalfopristin requires mecha nisms conferring resistance to both compounds. The SmaI macrorestriction pa tterns of strains from hospitals in Lille and Lyon were different; however, similarity analysis suggested a relatedness of 20 methicillin-resistant S. aureus strains from the Lille hospital, a finding confirmed by PCR typing based on three different genomic polymorphisms. These groups of isolates we re found to be hetero-glycopeptide-intermediate susceptible S. aureus. Info rmation about the failure of glycopeptide chemotherapy has not been availab le.