Pulsed-field gel electrophoresis typing of the methicillin-resistant staphylococci isolated from diabetic foot infections

Objective To study the characteristic of the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) isolated from diabetic foot ulcers. Methods Total of 24 MRSA and 18 MRSE strains were isolated from 388 diabetic-foot patients hospitalized from January 2008 to June 2010 in the Tianjin Metabolic Diseases Hospital. Pulsed-field gel electrophoresis (PFGE) was used to analyze the homology of the isolates. Results The similarities of MRSA was 42%-97%. The MRSA isolates were classified into 11 PFGE types (A-K), 12 were type A (11 of them were isolated from January to May in 2008), 2 strains were type B, 2 strains were type C and the other 8 types only found in one strain. The similarities of MRSE was 34%-100% and 14 PFGE types (A-N) were identified. Among MRSE strains, 5 were type A (including 3 type A1, 1 type A2, 1 type A3), and the other 13 types found only in one strain. Conclusion An outbreak of type A MRSA probably happened from January to May in 2008. No outbreak evidences have been identified from June 2008 to June 2010. Sporadic MRSE was found from January 2008 to June 2010 and no outbreak occurred. Key words: Diabetic foot; Infection; Methicillin-resistant Staphylococcus aureus; Methicillin-resistant Staphylococcus epidermidis; Pulsed-field gel electrophoresis