Image: Chest radiograph of an 88 year old man, about one week after onset of fever, fatigue and mild coughing. Lab tests detected both Influenza A virus and Haemophilus influenzae. It shows multifocal, patchy consolidation, mainly in the right upper lobe. By Mikael Häggström.
Scientists based at The University of Queensland have identified how a common bacterium is able to manipulate the human immune system during respiratory infections and cause persistent illness.
The research studied the virulence mechanisms of Haemophilus influenzae, a bacterium that plays a significant role in worsening respiratory tract infections. These bacteria are especially damaging to vulnerable groups, such as those with cystic fibrosis, asthma, the elderly, and Indigenous communities.
H. influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.
The bacterium persists by essentially turning off the body's immune responses, inducing a state of tolerance in human respiratory tissues. To draw on an analogy, the bacterium has a unique ability to 'talk' to and deactivate the immune system, convincing it there was no threat.
To demonstrate this, the researchers prepared human nasal tissue in the lab, growing it to resemble the surfaces of the human respiratory tract, then monitored gene expression changes over a 14-day 'infection'. They found very limited production of inflammation molecules over time, which normally would be produced within hours of bacteria infecting human cells.
Amazon promotion: Save 50.0% on select products from Syreinza with promo code 50J4IGLJ, through 7/15 while supplies last.
The researcher next applied both live and dead Haemophilus influenzae, showing the dead bacteria caused a fast production of the inflammation makers, while live bacteria prevented this. This proved that the bacteria can actively reduce the human immune response.
The consequence is that in cases where local immunity drops, for example during a viral infection, the bacteria may be able to 'take over' and cause a more severe infection.
These findings will lead to future work towards new treatments to prevent these infections by helping the immune system to recognise and kill these bacteria.
The research paper is: “Tolerance to Haemophilus influenzae infection in human epithelial cells: Insights from a primary cell-based model”. PLOS Pathogens, 2024; 20 (7): e1012282 DOI: 10.1371/journal.ppat.1012282
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)
No comments:
Post a Comment
Pharmaceutical Microbiology Resources