Comparison of Phenotypic MRSA Detection Methods with mecA gene PCR in a Tertiary Care Centre in India

Thampi, Dani Kochuplapparambil; Mundangalam, Nizamuddin; Pulikottil, Shoba Kurian; Jacob, Netto

doi:10.14260/jemds/2019/610

Cited by 2 publications

(1 citation statement)

References 11 publications

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“…Among 100 S. aureus isolates, 87% were resistant to Penicillin, 40% were resistant to Gentamicin, 27% were resistant to Co-trimaxozole, 32% were resistant to ciprofloxacin [ 18 - 20 ]. In our study, the overall rate of Inducible Clindamycin resistance among S. aureus was 24% and 37.2% in MRSA isolates and 15.8% among MSSA isolates [ 21 , 22 ].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Phenotypic and Genotypic Characterization Methods for the Detection of Methicillin-Resistant Staphylococcus Aureus

Rajeswarie¹,

Pradha²,

D'Souza³

et al. 2022

Cureus

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Introduction Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality due to the development of antimicrobial resistance secondary to irrational use of antibiotics, nonadherence to infection control practices, and increased use of intravascular devices in healthcare systems. Detection of MRSA is critical in clinical microbiology laboratories as it helps identify MRSA carriers and avoid treatment failure in patients. Hence, this study compared various phenotypic methods with the standard genotyping method to determine a method that permits rapid and accurate detection of MRSA. Materials & Methods Staphylococcus aureus ( S. aureus ) was initially identified based on colony morphology, Gram staining, standard biochemical tests, and antibiotic susceptibility using disk diffusion. MRSA was identified based on the detection of the mecA gene by polymerase chain reaction (PCR) and subsequent gel electrophoresis. Disk diffusion using cefoxitin or oxacillin and mannitol salt agar with 6-µg/ml oxacillin were used for phenotypic detection of MRSA. The D test was used to detect inducible clindamycin resistance in S. aureus isolates. Results Of the 100 S. aureus isolates analyzed, 37% were identified as MRSA by PCR and the cefoxitin disk diffusion method; however, only 31% were detected by the oxacillin disk diffusion method and 29% by the mannitol salt agar method. The sensitivity of the cefoxitin disk diffusion test, oxacillin disk diffusion, and mannitol salt agar methods was 86.05%, 83.78%, and 70.73%, respectively. Specificity was 100% for all the three phenotypic methods (p < 0.001). Notably, inducible clindamycin resistance was found in 37.2% of the MRSA isolates, indicating potential challenges in treatment. Conclusion Among the three phenotypic methods tested, the cefoxitin disk diffusion method had 100% sensitivity and specificity, which is similar to that of PCR-based MRSA detection. Hence, the cefoxitin disk diffusion method is recommended for use in clinical laboratories, where molecular methods are not available as it is both cost-effective and easy to perform.

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Section: Discussionmentioning

confidence: 99%

Comparison of Phenotypic and Genotypic Characterization Methods for the Detection of Methicillin-Resistant Staphylococcus Aureus

Rajeswarie¹,

Pradha²,

D'Souza³

et al. 2022

Cureus

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Discordant β-Lactam Susceptibility in Clinical Staphylococcus aureus Isolates: A Molecular and Phenotypical Exploration to Detect the BORSA/MODSA Isolates in Bogotá, Colombia

Fonseca-Fernández,

Mancera-García,

Leal-Castro

et al. 2024

Microorganisms

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Staphylococcus aureus is a human pathogen responsible for a wide range of diseases, such as skin and soft tissue infections, pneumonia, toxic shock syndrome, and urinary tract infections. Methicillin-resistant S. aureus (MRSA) is a well-known pathogen with consistently high mortality rates. Detecting the mecA resistance gene and phenotypical profile to β-lactams allows for the differentiation of MRSA from methicillin-susceptible S. aureus (MSSA) isolates. In this study, we characterized 57 S. aureus clinical isolates for β-lactam susceptibility and mecA presence. We classified 52.63% as MRSA and 45.61% as MSSA. However, some isolates evidenced different oxacillin resistance profiles, such as borderline oxacillin-resistant or modified S. aureus (BORSA/MODSA). The cefazolin inoculum effect (CzIE) was established for these samples, emphasizing the relevance of these isolates as a source of therapeutic failure. We also performed the detection of the Panton-Valentine Leucocidin virulence genes as well as the S. aureus spa-type clonality. As expected, spa-types t002 and t008 were the most prevalent clones, demonstrating the success of well-established clones. These findings emphasize the importance of establishing sensitivity profiles, especially in isolates with poor resistance mechanisms, to determine their prevalence and their impact on public health.

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Comparison of Phenotypic MRSA Detection Methods with mecA gene PCR in a Tertiary Care Centre in India

Cited by 2 publications

References 11 publications

Comparison of Phenotypic and Genotypic Characterization Methods for the Detection of Methicillin-Resistant Staphylococcus Aureus

Comparison of Phenotypic and Genotypic Characterization Methods for the Detection of Methicillin-Resistant Staphylococcus Aureus

Discordant β-Lactam Susceptibility in Clinical Staphylococcus aureus Isolates: A Molecular and Phenotypical Exploration to Detect the BORSA/MODSA Isolates in Bogotá, Colombia

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