Detection of Methicillin-Resistant Staphylococcus aureus (MRSA) using Modified Conventional Cefoxitin-based Media as an Alternative Screening

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) can cause infection with higher morbidity and mortality. In the limited-resource setting, the availability of rapid detection is scarce and may not be available; therefore, prompt detection using the alternative method is indispensable. To compare the detection rate of the modified-conventional method with chromogenic media against mucocutaneous clinical swab, a total of 80 S. aureus isolates from previous studies were cultivated and re-cultured into routine media such as blood agar (BA) and mannitol-salt agar (MSA) between June and September 2018. It directly inoculated from plain blood agar that had been incubated previous day before; it further underwent inoculation to other media, such as chromogenic media (CHROMagar), blood agar and mannitol salt agar that had been supplemented with cefoxitin (CFOX) powder manually. The sensitivity MSA-CFOX and BA-CFOX, respectively, was 96.88%. On the other hand, the sensitivity of CHROMagar and MHA-CFOX was 90.62%. The specificity of each MHA-CFOX, MSA-CFOX, and CHROMagar is 87.5% as well as 93.75% for BA-CFOX. The study has demonstrated better performance of modified-conventional method compared to the other media. Hence, the application of modified-media should not be delayed to facilitate the findings of MRSA among hospitalized patients.