Brief Article
Copyright ©2013 Baishideng. All rights reserved.
World J Transl Med. Aug 12, 2013; 2(2): 27-31
Published online Aug 12, 2013. doi: 10.5528/wjtm.v2.i2.27
Evaluation of three methods for detection of methicillin-resistant Staphylococcus aureus
Asli Gamze Sener, Sevin Kirdar, Ilhan Afsar, Mustafa Demirci
Asli Gamze Sener, Ilhan Afsar, Mustafa Demirci, Microbiology and Clinical Microbiology Laboratory, Ataturk Training and Research Hospital, 35360 Izmir, Turkey
Sevin Kirdar, Department of Microbiology and Clinical Microbiology, Adnan Menderes University, 09120 Aydın, Turkey
Author contributions: Gamze Sener A designed the research and wrote the paper; Kirdar S performed the research; Afsar I and Demirci M analyzed the data.
Correspondence to: Dr. Asli Gamze Sener, Associate Professor, Microbiology and Clinical Microbiology Laboratory, Ataturk Training and Research Hospital, 1834 sk. No. 9/4, 35360 Izmir, Turkey. agsener@gmail.com
Telephone: +90-232-2444444 Fax: +90-232-2444848
Received: February 5, 2013
Revised: May 13, 2013
Accepted: July 4, 2013
Published online: August 12, 2013
Abstract

AIM: To evaluate GenoType methicillin-resistant Staphylococcus aureus (MRSA) Direct assay and cultivation for the identification of MRSA by using mecA polymerase chain reaction (PCR) as the “gold standard” assay.

METHODS: In total of 61 nasal specimens from patients at the intensive care unit were studied by GenoType MRSA Direct test, conventional culture method and automated bacterial identification system. The results of GenoType MRSA Direct assay were compared to conventional culture method the identification of MRSA and mecA gene PCR as the “gold standard” method. The sensitivity, specificity, positive predictive value and negative predictive value were calculated.

RESULTS: In total, 61 specimens were studied. Fifty-four specimens (88.5%) were negative by all three methods. Six swabs (9.8%) were found positive by GenoType MRSA Direct test, conventional culture method and automated bacterial identification system. The presence of mecA in these strains was confirmed by PCR. One swab sample was negative for culture methods but MRSA and mecA gene were detected by GenoType MRSA Direct test and mecA PCR respectively. GenoType MRSA Direct test had a sensitivity of 100% (6/6) and a specificity of 100% (55/55), with a positive predictive value of 100% and a negative predictive value of 98%. Culture method of MRSA had a sensitivity of 83.3% (5/6) and a specificity of 98.2% (55/56).

CONCLUSION: It was found that the GenoType MRSA Direct assay, which is a rapid and accurate test, is of the same sensitivity and specificity with mecA PCR. The GenoType MRSA Direct assay can be a better tool for rapid and accurate detection of MRSA in diagnostic laboratories.

Keywords: Culture, Methicillin-resistant Staphylococcus aureus, Molecular assays

Core tip: For the identification of methicillin-resistant Staphylococcus aureus (MRSA), GenoType MRSA Direct assay and cultivation were evaluated by using mecA polymerase chain reaction (PCR) as the “gold standard” assay. Fifty-four specimens (88.5%) were negative by all three methods. Six swabs (9.8%) were found positive by GenoType MRSA Direct test, conventional culture method and automated bacterial identification system. The presence of mecA in these strains was confirmed by PCR. One swab sample was negative for culture methods but MRSA and mecA gene were detected by GenoType MRSA Direct test and mecA PCR respectively. It was found that the GenoType MRSA Direct assay, which is a rapid and accurate test, is of the same sensitivity and specificity with mecA PCR.