Rapid and sensitive detection of methicillin-resistant Staphylococcus aureus from blood culture bottle by real-time PCR

Abstract number: p1743

Eroglu  C., Yilmaz  H., Cakmak  U., Turan  D., Leblebicioglu  H.

The purpose of this study was to establish a rapid and sensitive real-time polymerase chain reaction (PCR) method for detection of methicillin-resistant Staphylococcus aureus (MRSA) from blood culture bottle. As a result of over use of broad-spectrum antibiotics after the 1960s in whole the world, an outbreak of MRSA infection has been seen. Severe nosocomial infections with MRSA such as bacteraemia and sepsis may lead to multiple organ failure and high mortality in the hospital. Although standard method took at least 48 hours to identify MRSA by the blood culture method, the presence of mecA and nuc genes which is specific for methicillin resistance and S. aureus was determined by real-time PCR method within only 2 hours after blood culture signal positivity. Nineteen S. aureus and 33 coagulase negative staphylococci positive blood culture bottles were studied retrospectively for detection of S. aureus and methicillin resistance. Staphylococci were identified with classical methods and MICs of oxacillin were determined by Etest (AB Biodisk) on Mueller-Hinton agar supplemented with 2% NaCl. Real-time PCR was performed to all positive blood culture samples for S. aureus and methicillin resistance determination. Nineteen (100%) S. aureus were determined correctly by real-time PCR method. Forty-four methicillin resistant and 8 methicillin sensitive staphylococci were detected by Etest. Using the real-time PCR method, the mecA gene was detected in 47 Staphylococci except 3. When compared with Etest and real-time PCR method gave sensitivity, specificity, and positive and negative predictive values of 100%, 63%, 94%, 100% for both positive and negative tests, respectively. Agreements between two methods were high (94%); there were 3 discrepant results among the 52 strains were tested. Detection of MRSA bacteraemia and methicillin resistance with real-time PCR definitely is useful for reducing mortality and morbidity of this type infection. In conclusion, this method, as many as sensitive and specific for detection of MRSA bacteraemia and clinically should be beneficial for prevention of unnecessary antibiotic use and determination of appropriate antibiotic treatments of MRSA infection.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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