Comparative evaluation of five culture media with triplex PCR assay for detection of methicillin-resistant Staphylococcus aureus.
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is responsible for nosocomial and community-acquired infections. Hence, rapid and accurate laboratory diagnosis of MRSA is a vital constituent of control measures. The present study evaluated five different methods for the identification of MRSA. A total of 207 S. aureus clinical isolates that consisted of 89 MRSA and 118 methicillin-susceptible S. aureus (MSSA) strains confirmed by PCR were tested. MRSA strains were evaluated by five different methods: chromogenic MRSA agar (CMRSA), oxacillin resistance screening agar base (ORSAB), mannitol salt oxacillin agar (MSO), mannitol salt cefoxitin agar with two different concentrations of cefoxitin [4 microg/ml (MSC-4) and 6 microg/ml (MSC-6)]. The results of the different methods were compared to mecA PCR as the gold standard. MSC-6 showed only six false-positive MRSA in comparison with PCR. The sensitivities and specificities of MSC-6, MSC-4, MSO-4, ORSAB, and CMRSA were as follows: 98.9/94.9%, 100/83.1%, 89.9/87.3%, 97.8/96.6%, and 95.5/94.9%, respectively. In comparison with PCR, it was found that both MSC-6 and ORSAB were relatively the least expensive screening tests ($0.70 and $1.00, respectively). In conclusion, all methods were comparable, but MSC-6 was the least expensive medium for MRSA screening.
Al-Talib
Hassanain
H
Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Kota Bharu, Kelantan, Malaysia. hassanainiy@yahoo.com
Yean
Chan Yean
CY
Al-khateeb
Alyaa
A
Singh
Kirnpal-Kaur Banga
KK
Hasan
Habsah
H
Al-Jashamy
Karim
K
Ravichandran
Manickam
M
D000362:Agar; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002440:Cefoxitin / Q000494:pharmacology; D003470:Culture Media; D006801:Humans; D008712:Methicillin / Q000494:pharmacology; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D003470:Culture Media; D002440:Cefoxitin; D000362:Agar; D008712:Methicillin; D010068:Oxacillin