Related Experiment Video
Updated: Nov 9, 2025
A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
Characterization of Antibiotic Resistance and Virulence Traits Present in Clinical Methicillin-Resistant
Basavaprabhu Haranahalli Nataraj1, Chette Ramesh1, Rashmi Hogarehalli Mallappa2
1Molecular Biology Unit, Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, 132001, India.
Abstract:
Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious superbug which poses serious health threats to humanity. The severity of the infections depends on the prevalence of virulence factors and antibiotic resistance. In this study, attempts have been made to nominate the two most virulent and multidrug-resistant MRSA isolates demonstrating the preliminary features of intestinal adhesion for the futuristic applications of probiotics and postbiotics as antagonists to combat MRSA infections. In this context, six clinical isolates of MRSA were polyphasically characterized for their identity, multidrug resistance, and few selected virulence determinates such as hemolytic activity and production of coagulase, nuclease, and capsule. The gut colonizing ability of MRSA isolates was assessed by mucoadhesion, auto-aggregation, and cell surface hydrophobicity. An antibiogram of MRSA isolates suggested the resistance towards several antibiotics with multiple antibiotic resistance (MAR) index >0.5 (12/241, 12/206, and 5/255) as well as their genome portraying mecA mediated methicillin resistance. Besides exhibiting strong biofilm formation ability, all the isolates exhibited positive responses towards tested virulence assays coupled with their genome displaying Coa, NucA, and CapE genes. On the other hand, isolates exhibited different levels of auto-aggregation (37.90 ± 1.8 to 51.53 ± 3.1%) and mucin adhesion ability (68.93 ± 0.61% to 86.62 ± 1.96%) with a significant (P ≤ 0.05) variation in adhesion to different hydrocarbons. Finally, multivariate Principal Component Analysis and Hierarchical Cluster Analysis (HCA) heatmap using Euclidean distance measurement indicated MRSA 12/206 and 5/255 as most resistant and virulent isolates with the potential to adhere to the hydrophobic gut niche.
Insights
Two virulent Methicillin-resistant Staphylococcus aureus (MRSA) isolates, 12/206 and 5/255, were identified. These multidrug-resistant superbugs show potential for gut adhesion, making them targets for probiotic and postbiotic therapies.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a significant global health threat due to its virulence and antibiotic resistance.
- Understanding MRSA's ability to colonize the gut is crucial for developing novel therapeutic strategies.
- The interplay between MRSA virulence factors and host interactions dictates infection severity.
Purpose of the Study:
- To identify and characterize the most virulent and multidrug-resistant MRSA clinical isolates.
- To assess the gut colonizing potential of selected MRSA isolates.
- To nominate MRSA strains for future studies exploring probiotics and postbiotics as antagonists.
Main Methods:
- Polyphasic characterization of six MRSA clinical isolates, including identity, antibiotic resistance profiling (MAR index), and virulence factor assessment (hemolytic activity, coagulase, nuclease, capsule genes).
- Evaluation of gut colonization ability through mucoadhesion, auto-aggregation, and cell surface hydrophobicity assays.
- Genomic analysis for mecA, Coa, NucA, and CapE genes. Multivariate statistical analyses (PCA, HCA) were employed for isolate discrimination.
Main Results:
- All MRSA isolates exhibited multidrug resistance (MAR index >0.5) and carried the mecA gene, confirming methicillin resistance.
- Isolates displayed significant biofilm formation, positive virulence assay results, and possessed Coa, NucA, and CapE genes.
- MRSA isolates 12/206 and 5/255 were identified as the most virulent and resistant, demonstrating significant auto-aggregation and mucin adhesion, with potential for hydrophobic gut niche colonization.
Conclusions:
- MRSA isolates 12/206 and 5/255 possess key characteristics of virulence and multidrug resistance, alongside gut adhesion capabilities.
- These selected MRSA strains serve as promising candidates for in-depth investigation into probiotic and postbiotic antagonism strategies.
- The findings highlight the potential of targeting gut-adherent MRSA strains with next-generation antimicrobial approaches.
Related Concept Videos
01:30Development of Antibiotic Resistance
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
00:57Antibiotic Selection