StemCell Therapy

Tiny bubble-like sacs called vesicles that travel around and between cells in the body can help to initiate and worsen secondary bacterial infections in people already infected with viral lung infections like colds, flu or even Covid-19.

According to research from the University of Pittsburgh School of Medicine, viral infection triggers the release of these iron-loaded vesicles, which then feed the bacteria with iron and encourage them to form hard-to-treat biofilms.

There is still a lot we need to learn about how microbes exploit the host during infections, especially in the complex setting of polymicrobial interactions, says the lead researcher on the study Jennifer Bomberger, an associate professor in the Department of Microbiology & Molecular Genetics at the University of Pittsburgh.

Understanding factors that permit the establishment of chronic infections, like those that are so devastating to patients with chronic lung diseases, is my laboratorys goal.

It is a known problem that a significant proportion of people who become infected with viral lung infections go on to develop secondary bacterial infections like pneumonia. This can be particularly problematic in patients with chronic lung conditions such as cystic fibrosis. However, less is known about factors that increase a persons risk for these secondary infections.

Bacterial pneumonia

For example, in the current pandemic more than a quarter of patients admitted to the emergency room with serious Covid-19 have also developed secondary bacterial infections. But what spares the other 60-75% of patients from these secondary infections is less clear.

The development of chronic bacterial infections often is preceded by acute viral infections, and such co-infections increase patients likelihood of death or lifelong disability, comments Bomberger. We wanted to understand what it is that the virus is doing that allows bacteria to get a foothold in the patients airways.

Vesicles are very common in the space between cells and often act like a delivery service taking proteins, genetic material like RNA, or fats, from one place in the body to another. Although they have been reported to change the local environment during viral infections and regulate virus-host interactions, very little is understood about the role they have in mediating between bacteria and viruses.

The bacteria Pseudomonas aeruginosa is known to cause a number of bacterial infections such as pneumonia and sepsis and can be difficult to treat due to drug resistance and biofilm formation. Bomberger and colleagues assessed links between infection with respiratory syncytial virus, which causes one type of common cold, and subsequent infection with P. aeruginosa in people with cystic fibrosis.

Weve previously shown that acute viral infections can change the environment of the respiratory tract to allow bacteria to grow as biofilms, communities of bacteria that are highly antibiotic resistant, says Bomberger.

Using various imaging and laboratory techniques the team found that vesicles released from lung tissue infected with respiratory syncytial virus seem to help P. aeruginosa bacteria form biofilms by feeding them iron.

Cells secreting exosomes, one type of extracellular vesicle found in the body.

It was not previously known that bacteria would interact with these vesicles made by the human host, so this now informs our thinking about many infection situations, but also leads us to think about new therapies based on the nutrients delivered on these host vesicles, says Bomberger.

Whether the amount of iron a person has in their blood, or other factors, influence the degree to which viral iron-charged vesicles are produced is unclear. But it is certainly true that iron is an important nutrient for many bacteria.

A possible treatment strategy like removal of excess iron via chelation drugs could be one new approach, probably used in combination with standard antimicrobials to treat the bacterial infections, according to Bomberger.

The research team now wants to investigate the relationship between the bacteria and these vesicles further. They also want to confirm their findings in patients with different types of co-infections and assess what impact these vesicles have on the patients immune system.

It would be interesting to see the implications this mechanism has for the hosts immune response, says Matthew Hendricks, a researcher at the University of Washington School of Medicine, who worked on the study while a graduate student in Bombergers laboratory.

If extracellular vesicles can shield bacteria from the immune cells, that could decrease the hosts ability to detect the infection and help bacteria evade the immune response.

Follow this link:
Risk Factor For Bacterial And Viral Co-Infection Uncovered - Forbes

This entry was posted on February 7, 2021 at 3:52 am and is filed under Molecular Genetics. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |