ABSTRACT
@#Abstract: Objective To screening new compounds that can inhibit the growth and biofilm formation of Staphylococcus aureus. Methods Compounds that can inhibit the growth of Staphylococcus aureus were screened from the FDA approved drug library by 96 well plates. The absorbance value of 600 nm wavelength (OD600) was measured by Microplate Reader to detect the growth of Staphylococcus aureus planktonic cells in the culture supernatant. The minimum inhibitory concentration (MIC) of ozanimod against Staphylococcus aureus clinical isolates were detected by micro broth dilution method. The inhibitory effect of sub-inhibitory concentrations of ozanimod on the biofilm formation of Staphylococcus aureus was detected by crystal violet staining. Results This study found that ozanimod could significantly inhibit the growth of Staphylococcus aureus SA113 (screening reference strain), and the MIC was 25.00 μmol/L. The MIC of ozanimod against 119 clinical isolates of Staphylococcus aureus [65 isolates of methicillin sensitive (MSSA) and 54 isolates of methicillin resistant (MRSA)] was 12.50 or 25.00 μmol/L. The MIC50 and MIC90 of ozanimod against the 119 Staphylococcus aureus isolates all were 25.00 μmol/L. This study found that 6.25, 12.50, 25.00 μmol/L of ozanimod could significantly inhibit the biofilm formation of 2 MSSA and 2 MRSA. The sub-MIC concentration of ozanimod (12.50 μmol/L) could significantly inhibit the biofilm formation of 14 MSSA and 11 MRSA, but had no inhibitory effect on the growth of planktonic cells of these Staphylococcus aureus isolates. Conclusion Ozanimod can inhibit the growth of Staphylococcus aureus, including MRSA, and has good antibacterial activity. The sub-MIC concentration of ozanimod could significantly inhibit the biofilm formation of Staphylococcus aureus.
ABSTRACT
In order to discover the risk factors for 30-day mortality in bloodstream infections (BSI) caused by Enterococcus spp.strains,we explored the clinical and therapeutic profile of patients with Enterococcus spp.BSI and the characteristics of this condition.A total of 64 patients with BSI caused by Enterococcus spp.who were treated in our hospital between 2006 and 2015 were included in the study.The clinical features of patients,microbiology,and 30-day mortality were collected from the electronic medical records database and analyzed.The results showed that there were 38 patients infected by Enterococcus faecalis (E.faecalis),24 by Enterococcus faecium (E.faecium),1 by Enterococcus casseliflavus (E.casseliflavus),and 1 by Enterococcus gallinarum (E.gallinarum).A Charlson comorbidity score ≥5,corticosteroid treatment,placement of catheters or other prosthetic devices and history of antibiotic use were found more frequently in E.faecium BSI patients than in E.faecalis patients (P=0.017,P=0.027,P=0.008 and P=0.027,respectively).Furthermore,the univariate and multivariate analysis showed that corticosteroid treatment (OR=17.385,P=0.008),hospital acquisition (OR=16.328,P=0.038),and vascular catheter infection (OR=14.788,P=0.025) were all independently associated with 30-day mortality.Our results indicate that E.faecalis and E.faecium are two different pathogens with unique microbiologic characteristics,which cause different clinical features in BSI,and the empiric antimicrobial treatments are paramount for patients with enterococcal BSI.