Related Experiment Video
Updated: Mar 14, 2026
Atomic Force Microscopy Combined with Infrared Spectroscopy as a Tool to Probe Single Bacterium Chemistry
Published on: September 15, 2020
Phenotypic characteristics and comparative proteomics of Staphylococcus aureus strains with different
Auttawit Sirichoat1, Aroonlug Lulitanond2, Rattiyaporn Kanlaya3
1Graduate School, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
Abstract:
Reduced vancomycin susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide problem. Unfortunately, its genetic marker and molecular mechanisms remained unknown. This study investigated differential phenotypic characteristic and protein expression profiles among three groups of MRSA isolates, including vancomycin-susceptible S. aureus (VSSA), heterogeneous vancomycin-intermediate S. aureus (hVISA) and vancomycin-intermediate S. aureus (VISA) (n = 7 isolates/group). Phenotypic characteristic revealed significant greater number of isolates with non-spreading colony in VISA as compared to both VSSA and hVISA groups. 2-DE followed by nanoLC-MS/MS analyses revealed increased glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in both hVISA and VISA, whereas 50S ribosomal protein L14 (RplN) and DNA-binding protein II (Hup) were increased only in VISA. The non-spreading colony and GAPDH level of MRSA may be used as the markers for differentiation of VSSA, hVISA and VISA.
Insights
Identifying markers for vancomycin-intermediate Staphylococcus aureus (VISA) is crucial. This study found non-spreading colonies and increased glyceraldehyde 3-phosphate dehydrogenase (GAPDH) can help differentiate VISA from other MRSA strains.
Area of Science:
- Microbiology and Infectious Diseases
- Molecular Biology
- Proteomics
Background:
- Reduced vancomycin susceptibility in methicillin-resistant Staphylococcus aureus (MRSA) is a growing global health concern.
- The genetic markers and molecular mechanisms underlying this reduced susceptibility remain largely unidentified.
- Accurate differentiation of vancomycin-susceptible S. aureus (VSSA), heterogeneous vancomycin-intermediate S. aureus (hVISA), and vancomycin-intermediate S. aureus (VISA) is clinically significant.
Purpose of the Study:
- To investigate differential phenotypic characteristics and protein expression profiles in MRSA isolates with varying vancomycin susceptibility.
- To identify potential molecular markers for distinguishing between VSSA, hVISA, and VISA.
- To elucidate underlying mechanisms contributing to reduced vancomycin susceptibility in MRSA.
Main Methods:
- Analysis of phenotypic characteristics, specifically colony morphology (spreading vs. non-spreading), across three MRSA groups (VSSA, hVISA, VISA).
- Two-dimensional gel electrophoresis (2-DE) to separate proteins from MRSA isolates.
- Nano-liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) for protein identification and quantification.
Main Results:
- A significantly higher proportion of VISA isolates exhibited non-spreading colony morphology compared to VSSA and hVISA groups.
- Increased levels of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were observed in both hVISA and VISA isolates.
- Elevated levels of 50S ribosomal protein L14 (RplN) and DNA-binding protein II (Hup) were specifically detected in VISA isolates.
Conclusions:
- Non-spreading colony morphology and elevated GAPDH levels in MRSA can serve as potential markers for differentiating VSSA, hVISA, and VISA.
- Specific protein alterations, including RplN and Hup, are associated with the VISA phenotype.
- These findings contribute to understanding the molecular basis of reduced vancomycin susceptibility in MRSA and aid in clinical differentiation.
