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Updated: May 29, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Evaluation of salt concentrations, chromogenic media and anatomical sampling sites for detection of
L J Pletinckx1, Y De Bleecker, J Dewulf
1Catholic University College South-West-Flanders (KATHO), Department HIVB, Wilgenstraat 32, 8800 Roeselare, Belgium. larissa.pletinckx@katho.be
Abstract:
The performance of chromogenic media for the detection of methicillin-resistant Staphylococcus aureus (MRSA) in humans, has been evaluated in numerous studies. However, few comparative studies have been performed for the detection of MRSA in pigs. In this study two different salt concentrations (2.5% or 7.5% NaCl) were evaluated in the enrichment nutrient broth and three selective chromogenic media (chromID MRSA, BrillianceMRSA and MRSASelect) for their ability to detect MRSA in swabs from 29 pigs obtained from three different anatomical sampling sites (anterior nares, skin behind both ears and perineum). ChromID MRSA showed the highest relative sensitivity and specificity after enrichment in 7.5% NaCl, followed by MRSASelect and BrilianceMRSA. For all chromogenic media more MRSA-positive results were obtained for specimens collected from skin behind the ears than for specimens taken from both nares and perineum. The results with regard to the anatomical sampling sites were confirmed in a larger study on three different pig farms involving 60 pigs per farm. Skin behind the ears was the anatomical site with the highest relative sensitivity (91.4%) for MRSA detection compared to perineum and anterior nares, with a relative sensitivity of 76.5% and 75.3%, respectively. An increased relative sensitivity could be achieved when combining two anatomical sites. Sampling of anterior nares and skin behind the ears appeared to be the most sensitive combination with a relative sensitivity of 98.2%. These results show that sampling of only the anterior nares underestimates the real pig MRSA prevalence.
Insights
This study evaluated chromogenic media for detecting methicillin-resistant Staphylococcus aureus (MRSA) in pigs. Sampling skin behind the ears, combined with anterior nares, significantly improved MRSA detection rates.
Area of Science:
- Veterinary Microbiology
- Diagnostic Microbiology
- Food Animal Health
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat to both animal and human health.
- While MRSA detection in humans is well-studied, comparative evaluations in pigs are limited.
- Understanding optimal sampling strategies is crucial for accurate MRSA surveillance in swine populations.
Purpose of the Study:
- To compare the performance of different chromogenic media and salt concentrations for MRSA detection in pigs.
- To identify the most effective anatomical sampling sites for MRSA surveillance in swine.
- To determine optimal enrichment and selective media combinations for accurate MRSA identification in pigs.
Main Methods:
- Two salt concentrations (2.5% and 7.5% NaCl) were tested in enrichment broth.
- Three selective chromogenic media (chromID MRSA, BrillianceMRSA, MRSASelect) were evaluated.
- Swabs from anterior nares, skin behind ears, and perineum of pigs were analyzed.
Main Results:
- ChromID MRSA with 7.5% NaCl enrichment demonstrated the highest sensitivity and specificity.
- Skin behind the ears yielded more positive MRSA results than nares or perineum.
- Combining anterior nares and skin behind the ears sampling significantly increased MRSA detection sensitivity (98.2%).
Conclusions:
- Sampling only the anterior nares underestimates the true prevalence of MRSA in pigs.
- The combination of skin behind the ears and anterior nares provides a highly sensitive method for MRSA detection in swine.
- Optimized enrichment and selective media, alongside strategic anatomical sampling, are essential for effective pig MRSA surveillance.
