Resistance class 1 integron in clinical methicillin-resistant Staphylococcus aureus strains in southern China, 2001-2006

As a novel antibiotic resistance determinant, investigation of the occurrence and characteristics of class 1 integron was performed on nosocomial methicillin-resistant Staphylococcus aureus (MRSA) strains sampled during 2001-2006. Seventy-six out of 179 (42.5%) of the tested strains were found to carry class 1 integrons, with four unique arrays of gene cassettes detected. This is the first report of the comprehensive identification and typing of class 1 integrons in clinical MRSA isolates over a 6-year period, representing the first evidence for class 1 integrons as possible antibiotic resistance determinants in clinical MRSA strains.