Risk factors and antimicrobial susceptibilities of severe community-acquired Staphylococcus aureus infections in Ningbo

Abstract

Objective To identify antimicrobial susceptibilities of community-acquired Staphylococcus aureus infections and the risk factors of severe infections. Methods Clinical data of 184 cases of community-acquired Staphylococcus aureus infections collected from 4 hospitals in Ningbo during May 2008 and May 2013 were reviewed. Microbial sensitivity test and virulence genes (pvl and tst) detection were performed in clinical isolates, and SCCmec genotyping was performed in methicillin-resistant Staphylococcus aureus (MRSA) strains. Binary logistic regression analysis was used to identify the risk factors for severe infections. Results Among 184 cases of community-acquired Staphylococcus aureus infections, 39 (21.20%) were severe cases. Staphylococcus aureus strains were highly resistant to penicillin, erythromycin and clindamycin, but more than 75% strains were sensitive to oxacillin, aminoglycosides, quinolones, rifampicin and vancomycin. Logistic regression analysis showed that advanced age (OR=1.024, 95%CI: 1.005-1.043, P<0.05), malignant tumor (OR=15.288, 95%CI: 1.609-145.229, P<0.05), autoimmune diseases or long-term hormone therapy (OR=12.102, 95%CI: 2.082-70.338, P<0.01) were risk factors for severe community-acquired Staphylococcus aureus infections. Conclusions Strains isolated from the patients with community-acquired Staphylococcus aureus infections in Ningbo are usually sensitive to oxacillin, aminoglycosides, quinolones, rifampicin and vancomycin, which may be recommended for clinical use. Elder patients and those with malignant tumor, autoimmune diseases or long-term hormone therapy are more likely to develop severe Staphylococcus aureus infections. Key words: Community-acquired infections; Staphylococcus aureus; Risk factors; Microbial sensitivity tests