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MALDI-TOF-MS based identification and molecular characterization of food associated methicillin-resistant
1Department of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysuru-570006, Karnataka, India.
Abstract:
Food-borne methicillin resistant Staphylococcus aureus (MRSA) is involved in two-fold higher mortality rate compared to methicillin susceptible S. aureus (MSSA). Eventhough Mysuru recognized as cleanest city in the world, prevalence of food contamination is not detailed. The aim is to screen food samples from Mysuru area and to characterize MRSA strain, employing MALDI-Biotyper, multiplex PCR to distinguish between MRSA and MSSA by PCR-coupled single strand conformation polymorphism (PCR-SSCP). Of all the food-borne pathogens, S. aureus contamination accounts for 94.37 ± 0.02% (P < 0.01), strains characterized by means of nuc genes, followed by species specific identification by Coa, Eap and SpA genes and multiplex PCR to confirm the presence of three methicillin resistant staphylococcal species simultaneously using nuc and phoP genes. Amplification of mecA gene in 159 isolates confirmed that all strains are methicillin resistant, except UOM160 (MSSA) and multi-drug resistant (MDR) in 159 isolates confirmed by 22 sets of β-lactam antibiotics. MSSA and MDR-MRSA were discriminated by PCR-SSCP using nuc gene for the first time. From the present studies, compared to conventional methods MALDI-Biotyper emerged as an effective, sensitive (>99%), robust (<2 min), and alternative tool for pathogen identification, and we developed a PCR-SSCP technique for rapid detection of MSSA and MRSA strains.
Insights
Food contamination with methicillin-resistant Staphylococcus aureus (MRSA) is a significant health concern. This study screened food samples in Mysuru, identifying MRSA and developing rapid detection methods for methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA).
Area of Science:
- Food safety and microbiology
- Antimicrobial resistance
- Molecular diagnostics
Background:
- Food-borne methicillin-resistant Staphylococcus aureus (MRSA) poses a higher mortality risk than methicillin-susceptible S. aureus (MSSA).
- Limited data exists on food contamination prevalence in Mysuru, despite its reputation for cleanliness.
- Staphylococcus aureus is a prevalent foodborne pathogen, necessitating detailed characterization.
Purpose of the Study:
- To screen food samples from Mysuru for Staphylococcus aureus contamination.
- To characterize methicillin-resistant Staphylococcus aureus (MRSA) strains.
- To develop and validate rapid diagnostic techniques for distinguishing MRSA from MSSA.
Main Methods:
- Utilized MALDI-Biotyper for bacterial identification.
- Employed multiplex PCR with nuc, Coa, Eap, SpA, and phoP genes for strain characterization.
- Developed and applied PCR-coupled single-strand conformation polymorphism (PCR-SSCP) for MRSA/MSSA discrimination.
Main Results:
- Staphylococcus aureus contamination was found in 94.37% of food samples.
- Multiplex PCR confirmed the presence of methicillin resistance genes (mecA) in most isolates.
- PCR-SSCP successfully differentiated methicillin-resistant Staphylococcus aureus (MRSA) from methicillin-susceptible S. aureus (MSSA).
- MALDI-Biotyper proved to be a rapid, sensitive, and robust tool for pathogen identification.
Conclusions:
- This study highlights the prevalence of Staphylococcus aureus in Mysuru's food supply.
- Developed PCR-SSCP offers a rapid method for distinguishing MRSA from MSSA.
- MALDI-Biotyper is an effective alternative to conventional methods for bacterial identification.
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