A single natural nucleotide mutation alters bacterial pathogen host tropism

Area of Science:

• Microbiology
• Evolutionary Biology
• Genetics

Background:

• Microbial pathogens can change hosts, leading to epidemics affecting public and animal health.
• Understanding the genetic basis of host switching is crucial for predicting and controlling pathogen spread.

Purpose of the Study:

• To investigate the molecular mechanisms behind a bacterial host-switching event.
• To trace the evolutionary history of the rabbit-specific Staphylococcus aureus clone.

Main Methods:

• Evolutionary trajectory analysis of Staphylococcus aureus.
• Identification of genetic mutations responsible for host tropism alteration.

Main Results:

• Staphylococcus aureus likely host-jumped from humans to rabbits over 40 years ago.
• A single nucleotide mutation was sufficient to enable a human-specific strain to infect rabbits.
• Convergent evolution was observed, with similar mutations found in different rabbit strains.

Conclusions:

• A single genetic mutation can be sufficient to alter a microorganism's host tropism.
• Pathogens possess a significant capacity to adapt and expand into new host populations.
• This study provides a molecular basis for understanding bacterial host jumps and epidemic emergence.