BackgroundS.aureus is a predominant pathogen that causes infection in critically ill patients, but little information exists regarding the characterization of S. aureus from different sources in burn patients in southeastern China.MethodsWe enrolled 125 patients with S. aureus infection in burns center between Jan 2014 and Dec 2015. S. aureus isolates were characterized by antimicrobial susceptibility test, toxin gene detection, and molecular typing with multilocus sequence type, staphylococcal protein A (spa) type, and staphylococcal cassette chromosome mec (SCCmec) type.ResultsSixty-eight MRSA were isolated from SSTI and 31 from non-SSTI patients, respectively. Overall, the drug-resistant ability of S. aureus isolated from SSTI was higher than that from non-SSTI groups. SCCmecIII-CC239-t030 was the most common clone (38 from SSTIs, and 8 from non-SSTIs). Seg was the most common enterotoxin gene (21 from SSTIs and 33 from non-SSTIs). Isolates from SSTIs was more likely to carry seb (P = 0.04), while those from non-SSTIs tended to carry sea and seg (P = 0.002 and 0.01, respectively). Although isolates carried four hemolysin genes, there was no significant difference between them (P > 0.05).ConclusionSCCmecIII-CC239-t030 was the most common clone in Jiangxi burns center, China. The molecular characterization of S. aureus was quite different between SSTI and non-SSTI groups.

A growing body of evidence indicates that the immune system plays a central role in sepsis. By analyzing immune genes, we sought to establish a robust gene signature and develop a nomogram that could predict mortality in patients with sepsis. Herein, data were extracted from the Gene Expression Omnibus and Biological Information Database of Sepsis (BIDOS) databases. We enrolled 479 participants with complete survival data using the GSE65682 dataset, and grouped them randomly into training (n = 240) and internal validation (n = 239) sets based on a 1:1 proportion. GSE95233 was set as the external validation dataset (n=51). We validated the expression and prognostic value of the immune genes using the BIDOS database. We established a prognostic immune genes signature (including ADRB2, CTSG, CX3CR1, CXCR6, IL4R, LTB, and TMSB10) via LASSO and Cox regression analyses in the training set. Based on the training and validation sets, the Receiver Operating Characteristic curves and Kaplan-Meier analysis revealed that the immune risk signature has good predictive power in predicting sepsis mortality risk. The external validation cases also showed that mortality rates in the high-risk group were higher than those in the low-risk group. Subsequently, a nomogram integrating the combined immune risk score and other clinical features was developed. Finally, a web-based calculator was built to facilitate a convenient clinical application of the nomogram. In summary, the signature based on the immune gene holds potential as a novel prognostic predictor for sepsis.

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The accuracy of Vitek 2, WalkAway 40, and DL-96 systems for susceptibility testing of penicillin against 547 S. aureus was evaluated using broth micro dilution. BlaZ gene was taken as gold standard to predict penicillinase-producing or not. Overall, there are no very major error in Vitek 2, one in WalkAway 40 and seven in DL-96. No major errors and 59 minor errors were noted in this study. The results showed that Vitek 2 had more reliable rate to predict penicillinaseproducing S. aureus.