<abstract xmlns="http://www.w3.org/1999/xhtml"><sec><h3>Background</h3><p><italic>Staphylococcus aureus</italic> is one of the common opportunistic gram-positive pathogens which are often associated with nosocomial infections. Detection of methicillin-resistant <italic>S. aureus</italic> (MRSA) has become complicated due to the complex phenotypic and genomic pattern.</p></sec><sec><h3>Objective</h3><p>To evaluate the sensitivity and specificity pattern of various phenotypic methods used in screening <italic>mec</italic> genes harboring MRSA.</p></sec><sec><h3>Methods</h3><p>Clinical isolates of <italic>S. aureus</italic> were collected from diagnostic centers in Tamil Nadu. Phenotypic identification methods such as Minimal Inhibitory Concentration for oxacillin, oxacillin screen agar (OSA), oxacillin disk diffusion, and cefoxitin disk diffusion (CFD) tests were compared. The clinical isolates were classified into MRSA and methicillin-susceptible <italic>S. aureus</italic> (MSSA) based on the polymerase chain reaction (PCR) amplification of the <italic>mec</italic>A gene.</p></sec><sec><h3>Result</h3><p>Out of 50 <italic>S. aureus</italic>, 21 were found to be MRSA based on the presence of the <italic>mec</italic>A gene. All 21 <italic>mec</italic>A-positive isolates were found to be resistant through minimum inhibitory concentration (MIC) and CFD test, having a sensitivity of 100% and specificity of 52% and 62%, respectively. OSA and oxacillin disk tests were found to have a sensitivity of 86% and specificity of 48% and 52%, respectively.</p></sec><sec><h3>Conclusion</h3><p>The combination of two phenotypic methods, CFD and oxacillin MIC, can be used for the detection of MRSA in clinical laboratories.</p></sec></abstract>

BackgroundStaphylococcus aureus is one of the common opportunistic gram-positive pathogens which are often associated with nosocomial infections. Detection of methicillin-resistant S. aureus (MRSA) has become complicated due to the complex phenotypic and genomic pattern.ObjectiveTo evaluate the sensitivity and specificity pattern of various phenotypic methods used in screening mec genes harboring MRSA.MethodsClinical isolates of S. aureus were collected from diagnostic centers in Tamil Nadu. Phenotypic identification methods such as Minimal Inhibitory Concentration for oxacillin, oxacillin screen agar (OSA), oxacillin disk diffusion, and cefoxitin disk diffusion (CFD) tests were compared. The clinical isolates were classified into MRSA and methicillin-susceptible S. aureus (MSSA) based on the polymerase chain reaction (PCR) amplification of the mecA gene.ResultOut of 50 S. aureus, 21 were found to be MRSA based on the presence of the mecA gene. All 21 mecA-positive isolates were found to be resistant through minimum inhibitory concentration (MIC) and CFD test, having a sensitivity of 100% and specificity of 52% and 62%, respectively. OSA and oxacillin disk tests were found to have a sensitivity of 86% and specificity of 48% and 52%, respectively.ConclusionThe combination of two phenotypic methods, CFD and oxacillin MIC, can be used for the detection of MRSA in clinical laboratories.

Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant <italic>Staphylococcus aureus</italic>

Department of Biomedical Sciences, School of Bioscience and Technology

Department of Clinical Sciences, College of Health and Human Sciences

Asian Biomedicine

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant 

BackgroundStaphylococcus aureus is one of the common opportunistic gram-positive pathogens which are often associated with nosocomial infections. Detection of...

Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant Staphylococcus aureus

Article Category: Technical report

Published Online: Jun 25, 2020

Page range: 225 - 233

DOI: https://doi.org/10.1515/abm-2019-0065

Keywords
cefoxitin, heterogenous population,

© 2019 Archana Loganathan et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant Staphylococcus aureus

Article Category: Technical report

Published Online: Jun 25, 2020

Page range: 225 - 233

DOI: https://doi.org/10.1515/abm-2019-0065

Keywordscefoxitin, heterogenous population,

© 2019 Archana Loganathan et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
cefoxitin, heterogenous population,