Characterization of Staphylococcus aureus Isolated from Non-Native Patients with Skin and Soft Tissue Infections in Shanghai.

BACKGROUND: Staphylococcus aureus is one predominant cause of skin and soft-tissue infections (SSTIs), but little information exists regarding the characterization of S. aureus from non-native patients with SSTIs in China. METHODS: In this study, we enrolled 52 non-native patients with S. aureus SSTIs, and 65 native control patients with S. aureus SSTIs in Shanghai. 52 and 65 S. aureus isolates were collected from both groups, respectively. S. aureus isolates were characterized by antimicrobial susceptibility testing, toxin gene detection, and molecular typing with sequence type, spa type, agr group and SCCmec type. RESULTS: Methicillin-resistant S. aureus (MRSA) was detected in 8 non-native patients and 14 native patients with SSTIs. Overall, antimicrobial susceptibilities of S. aureus isolated from non-native patients were found higher than those from native patients. CC59 (ST338 and ST59) was found in a total of 14 isolates (4 from non-native patients; 10 from native patients), 9 of which were carrying lukS/F-PV (3 from non-native patients; 6 from native patients). ST7 was found in 12 isolates and all 12 isolates were found in native patients. The livestock-associated clone ST398 was found in 11 isolates (6 from non-native patients; 5 from native patients), and 5 ST398 lukS/F-PV-positive methicillin-susceptible S. aureus (MSSA) were all discovered among non-native patients. The molecular epidemiology of S. aureus isolated from non-native patients was quite different from those from native patients. lukS/F-PV was more frequent in isolates originating from non-native patients with SSTIs compared to native patients (31 vs. 7, P <0.0001). CONCLUSIONS: CC59 was the most common clonal complex among patients with SSTIs in Shanghai. The other most common sequence types were ST7 and Livestock ST398. The molecular epidemiology of S. aureus isolated from non-native patients was quite different from those from native patients. S. aureus isolated from non-native patients was more likely to carry lukS/F-PV.

Molecular epidemiologic analysis of Staphylococcus aureus isolated from four burn centers.

Staphylococcus aureus has been a major cause of hospital-acquired infections. Methicillin-resistant Staphylococcus aureus (MRSA) has emerged since 1980s as an epidemiologic problem in hospitals. This old pathogen brings a new challenge to all physicians and bacteriologists. Hence, effective measures of MRSA control are in critical need. S. aureus or MRSA is one of the leading causes of infection among burn centers, resulting in a number of poor outcomes and even death. The present study performed a molecular epidemiologic analysis of S. aureus isolated from four burn centers in the southeast of China. A total of 85 isolates were collected, and molecular characters were determined for further investigation. In this study, the prevalent clone of MRSA among four burn centers was found to be SCCmec III (spa-type t030, agr I), which is resistant to 4 kinds of antimicrobials including erythromycin, clindamycin, kanamycin and mupirocin. Discrepancy between mecA detection and conventional tests used for MRSA identification was observed unintentionally. Our data demonstrated that the overall prevalence rate of MRSA was 55.3%, and drugs such as sulfamethoxazole/trimethoprim, linezolid and fusidic acid are efficient antibiotic options for treating S. aureus or MRSA infections among four burn centers studied in present investigation.