Abstract:

[Abstract] Objective  To investigate resistance profile，antimicrobial-resistant genes and virulence genes carried by 60 staphylococcus aureus collected from bloodstream infections in General Hospital of Tianjin Medical University from 2006 to 2011. Methods  The bacteria identification and the antimicrobial susceptibility test were conducted by VITEK-2 compact automatic system. Methicillin resistant staphylococcus aureus (MRSA) were screened by disk diffusion method with cefoxitin. The polymerase chain reaction（PCR）was used to detect genes of mecA, qacA, pvl, sea, seb，sec1，sed，see and TSST-1. Results  The resistance rates of 60 isolates to penicillin, erythromycin, clindamycin and gentamicin were 91.7%, 65.0%, 65.0% and 40.0%, respectively. All of the isolates were susceptible to vancomycin, linezolid, and tigecycline. Among the 60 isolates, the positive rates of mecA and qacA were13 (21.7%) and 3(5.0%) respectively. The positive rates of pvl，sea， seb，sec and sed were 4 (6.7%)，20(33.3%), 3 (5%)，9 (15.0%) and 7 (11.7%). Both see and tst were negative in all strains. Conclusion  The resistance rates of staphylococcus aureus collected from bloodstream infections were high to penicillin , erythromycin, clindamycin and gentamicin. The various toxin and the antimicrobial-resistant genes were positive in staphylococcus aureus. We should pay attention to the detection of the antimicrobial-resistant gene and virulence gene.

Key words: staphylococcus aureus, bloodstream infections, virulence gene, antimicrobial-resistant gene