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Published on: June 30, 2023
Effect of antibiotics on mechanical properties of Bordetella pertussis examined by atomic force microscopy
M I Villalba1, L Venturelli2, L Arnal3
1Laboratory of Biological Electron Microscopy (LBEM), Institute of Physics (IPHYS), Faculty of Basic Sciences (SB), Swiss Federal Institute of Technology (EPFL), and Dept. of Fundamental Biology, Faculty of Biology and Medicine, University of Lausanne (UNIL), CH-1015 Lausanne, Switzerland; Centro de Investigación y Desarrollo en Fermentaciones Industriales (CINDEFI), Facultad de Ciencias Exactas, Universidad Nacional de La Plata - CONICET, 1900 La Plata, Argentina.
Abstract:
In recent years, the coevolution of microorganisms with current antibiotics has increased the mechanisms of bacterial resistance, generating a major health problem worldwide. Bordetella pertussis is a bacterium that causes whooping cough and is capable of adopting different states of virulence, i.e. virulent or avirulent states. In this study, we explored the nanomechanical properties of both virulent and avirulent B. pertussis as exposed to various antibiotics. The nanomechanical studies highlighted that only virulent B. pertussis cells undergo a decrease in their cell elastic modulus and height upon antimicrobial exposure, whereas their avirulent counterparts remain unaffected. This study also permitted to highlight different mechanical properties of individual cells as compared to those growing in close contact with other individuals. In addition, we analyzed the presence on the bacterial cell wall of Filamentous hemagglutinin adhesin (FHA), the major attachment factor produced by virulent Bordetella spp., under different virulence conditions by Force Spectroscopy.
Insights
Virulent Bordetella pertussis (whooping cough bacteria) shows reduced cell stiffness and height when exposed to antibiotics, unlike avirulent strains. This reveals distinct nanomechanical responses to antimicrobials.
Area of Science:
- Microbiology
- Nanotechnology
- Biophysics
Background:
- Antibiotic resistance in microorganisms is a growing global health concern.
- Bordetella pertussis, the causative agent of whooping cough, exhibits distinct virulent and avirulent states.
- Understanding bacterial responses to antibiotics at the nanoscale is crucial for developing new treatments.
Purpose of the Study:
- To investigate the nanomechanical properties of virulent and avirulent Bordetella pertussis.
- To determine the effect of various antibiotics on bacterial cell mechanics.
- To analyze the presence of Filamentous hemagglutinin adhesin (FHA) under different virulence conditions.
Main Methods:
- Atomic Force Microscopy (AFM) for nanomechanical property analysis (elastic modulus, height).
- Force Spectroscopy to analyze FHA presence on the bacterial cell wall.
- Comparison of mechanical properties between individual cells and cells in close contact.
Main Results:
- Virulent B. pertussis cells showed a significant decrease in elastic modulus and height upon antibiotic exposure.
- Avirulent B. pertussis cells remained mechanically unaffected by antimicrobial agents.
- Differences in mechanical properties were observed between isolated cells and those in colonies.
- FHA presence varied under different virulence states, analyzed via Force Spectroscopy.
Conclusions:
- Nanomechanical profiling can differentiate between virulent and avirulent B. pertussis responses to antibiotics.
- Virulent B. pertussis exhibits mechanical vulnerability to antimicrobials, suggesting potential therapeutic targets.
- Cellular mechanical properties are influenced by both virulence state and growth context (individual vs. colony).
