Characterization of S.aureus strains from two Turkish hospitals

Abstract number: P1061

Alalem A., Avsaroglu M.D., Bozoglu F.

Objectives: To characterize the S. aureus strains obtained from two hospitals in Turkey during June-August 2007 according to their antimicrobial susceptibilities, some genetic determinants and PVL-gene content.

Methods: 305 samples were collected from Ankara and Hacettepe hospitals. The strains were isolated from different clinical origin samples on blood agar. Cultures were maintained on glass beads by using Microbank at -70°C. Confirmation was done by Gram's staining, coagulase-, and catalase-tests followed by Phoenix Automated Microbiology System (BD Diagnostic Systems) analyses. Antimicrobial susceptibilities of the strains were investigated by disk diffusion method against 12 different antimicrobials, and only when oxacillin resistance observed, the MIC value of oxacillin was detected by E-test by CLSI standards for all. Genetic determinants were analyzed for randomly selected 30 strains. The studies were carried out with the StaphPlex system for 18 genetic determinants and monitored with the Liquichip200 Workstation.

Results: In this study out of 305 isolates, 95.7% was confirmed as S. aureus and 4.3% were CoNS. Except 30, all isolates were resistant to one or more antimicrobials. All oxacillin resistant isolates displayed the MIC value of at geqslant R: gt-or-equal, slanted256ug/ml There were 7 OXA resistant CoNS out of 13 isolates. Among S. aureus isolates, 46% were MSSA and 54% were MRSA. The VRSA was only 2% and there were no intermediate susceptibility observed. The majority MRSA isolates were multi-resistant to more than five classes of antibiotics (84.2%) and the resistant patterns differed. The results of genetic investigations indicated that the mecA gene was present in the majority of randomly selected 30 isolates; the community acquired MRSA type (ccr-BIV) was present in three and there was no case found to carry the hospital acquired MRSA type (ccr-BI, -II, -III). Besides the methicillin resistance gene, only tetracycline resistance determinants were obtained astetM and tetK. The prevalence of PVL gene was low (only one isolate).

Conclusion: Although there was high prevalence of S. aureus among tested clinical samples, there is no clonal spread of a specific isolate according to phenotypical characterization. Multi-resistance of MRSA isolates would be considered as a potential threat in Turkish hospitals based on two hospitals results. Low incidence of VRSA isolates indicates that vancomycin could be the drug for the treatment of S. aureus infections in Turkey.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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