Professor Frédéric Veyrier of the INRS-Institut Armand-Frappier Research Centre, along with his colleagues has recently claimed that the shape of pathogenic bacteria residing inside the nasopharynx is being altered with time – bacillus to coccus. Findings of the evolutionary study were published in the journal PLOS Genetics, and are suggestive of these bacteria becoming better at escaping the immune system and defense mechanisms of the host.

What Causes– Bacteria Evolving Shape

Evolution works in mysterious ways, sometimes even molding the shape of living organisms to confer them a selective survival advantage. Researchers now believe that this might also be happening at the microscopic level – stick-shaped (bacillus) bacteria might be shifting to a spherical (coccus) configuration – making bacteria more resilient and infectious.

Public health officials strictly monitor respiratory infections, since they are the leading cause of death worldwide. The pathogens responsible for these outbreaks – Neisseria meningitidis and Moraxella catharralis – have evolved and adapted according to the environment of the host’s nasal passages, making them defeat immune defenses. Genetic analysis of the predecessors of these pathogenic microbes highlighted an important gene, namely yacF. This gene has made the process of shape-changing possible and assists evolution. Through this study, it was observed that N. meningitidis and M. catharralis present today were spherical (coccus) strains and lacked the yacF gene.

Could A Change In Shape Help?

This shift from sticks to spheres allows certain molecules on the surface of bacteria, known as peptidoglycans, to change their composition and evolve. These compounds play a very significant role in the way our immune system detects the presence of pathogenic microbes.

“We have long believed that the shape of bacteria was a fixed variable; we even use it as a way to classify them”, stated Professor Veyrier. “This research demonstrates that the environment in which the bacteria evolve has an impact on their morphology. These results are exciting because we were able to identify the same change in two different species – the impact of which could be a key aspect in the specific way these pathogens are adapting to the human nasopharynx”.

The exact mechanism through which bacterial species maintain their shape is still a mystery. Conducting an in-depth study into this evolutionary process could help researchers develop more potent treatment and prevention strategies. The results of this study could provide answers to why current medicines are failing, and what tools are needed to adequately fight these new generation pathogens.