Related Experiment Video

Updated: May 10, 2026

Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
14:04

Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Published on: May 8, 2013

Phenotypic and genotypic methods for the detection of methicillin resistant coagulase negative staphylococci: a

Shubhra Singh1, Gopa Banerjee, S K Agarwal

  • 1P.G. Department of Microbiology, CSMMU, Lucknow.

The Journal of Communicable Diseases
|June 22, 2013
PubMed

Insights

Methicillin-resistant Coagulase-negative Staphylococci (CoNS) are a growing threat. This study compared phenotypic methods to PCR for detecting methicillin resistance, finding MHOX effective for identifying mecA gene-mediated resistance.

Area of Science:

  • Clinical Microbiology
  • Infectious Diseases
  • Molecular Diagnostics

Background:

  • Coagulase-negative Staphylococci (CoNS) are a leading cause of nosocomial infections.
  • Methicillin-resistant CoNS (MRCoNS) present a significant clinical challenge.
  • Accurate and rapid detection of methicillin resistance is crucial for effective treatment.

Purpose of the Study:

  • To compare the efficacy of various phenotypic methods with genotypic Polymerase Chain Reaction (PCR) for detecting methicillin resistance in CoNS.
  • To evaluate the diagnostic performance of oxacillin and cefoxitin in different phenotypic assays.
  • To identify the most reliable method for identifying mecA gene-mediated methicillin resistance in CoNS.

Main Methods:

  • 100 CoNS isolates were analyzed.
  • Phenotypic methods included disk diffusion (DD), agar dilution (AD), and Methoxyoxacillin (MHOX) testing using oxacillin and cefoxitin.
  • Genotypic detection of the mecA gene via PCR served as the gold standard.

Main Results:

  • Disk diffusion showed sensitivities of 92.30% (oxacillin) and 88.46% (cefoxitin), with specificities of 87.5% and 100%, respectively.
  • Agar dilution yielded sensitivities of 86.53% (oxacillin) and 80.76% (cefoxitin), with specificities of 79.16% and 85.41%, respectively.
  • MHOX demonstrated a high sensitivity of 96.16% but a lower specificity of 72.91%.

Conclusions:

  • Cefoxitin disk diffusion and oxacillin agar dilution can serve as effective initial tests for MRCoNS detection.
  • The MHOX method shows potential as a single, reliable assay for identifying mecA gene-mediated oxacillin resistance across all CoNS species.

More Related Videos

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus09:03

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus

Published on: September 5, 2013

Related Concept Videos

Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Modern Molecular Taxonomy01:29

Modern Molecular Taxonomy

Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...
Methods of Classification and Identification01:28

Methods of Classification and Identification

Bacterial identification relies on a diverse array of techniques to classify and understand microorganisms, each tailored to uncover specific characteristics. Traditional morphological approaches, while still valuable, are limited for closely related or structurally simple organisms. Modern methods integrate biochemical, serological, genetic, and advanced molecular tools to achieve greater accuracy.Morphological and Biochemical TechniquesMorphological characteristics, such as cell shape and...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...