Influenza A potentiates pneumococcal co-infection: New details emerge

September 22, 2014

Influenza infection can enhance the ability of the bacterium Streptococcus pneumoniae to cause ear and throat infections, according to research published ahead of print in the journal Infection and Immunity.

In the study, the investigators infected mice with either influenza alone, pneumococci alone, or both at once, and then monitored the populations of bacteria and virus over time. They also monitored the mice for development of middle ear infection.

Influenza infection enhanced the bacterium's ability to colonize the nasopharynx, and to infect the normally sterile middle ear.

"We learned that once influenza virus is introduced, all of the "rules" regarding phase variants are out the window," says corresponding author W. Edward Swords of Wake Forest University, Winston-Salem, NC. Phase variation refers to the fact that the colonizing bacteria have transparent cell surfaces, while those that spread within the host have opaque surfaces.

"However, in the presence of influenza, opaque variants can readily colonize the nasopharynx, and transparent variants can persist in the ear," says Swords. "This indicates that the host environs are more permissive for infection by the entire bacterial population."

Furthermore, recent research had shown that influenza interferes with innate immunity in a way that enables pneumococci to flourish. In this research, Swords shows that that interference manifests as increased inflammatory responses at the mucosal surface in the influenza-infected mice, such as within the middle ear, and in the nasopharynx.

"As with most pneumococcal infections, it should be appreciated that localized nonlethal infections are much more common than the rapidly lethal presentations," says Swords. "For example, influenza is a contributing factor in otitis media (middle ear infections) in children."

"If we can understand why and how viral infection causes bacteria to colonize privileged sites like the middle ear, we will better know what aspects of disease to focus on with preventive or therapeutic treatments," says Swords.
-end-
The manuscript can be found online at http://bit.ly/asmtip0914f. The final version of the article is scheduled for the November 2014 issue of Infection and Immunity.

Infection and Immunity is a publication of the American Society for Microbiology (ASM). The ASM is the largest single life science society, composed of over 39,000 scientists and health professionals. Its mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

American Society for Microbiology

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.