NEW YORK, Jan. 11 (UPI) -- A study from the New York University School of Medicine Langone Medical Center has determined how the bacteria Streptococcus pneumoniae, or pneumococcus, is spread.
Researchers have found that the bacteria secretes a toxin that helps it jump from one person to the next, aided by a person's immune defenses.
S. pneumoniae is responsible for millions of infections worldwide each year, often infecting the nasal cavity, sinuses and lungs. It can be deadly in children, the elderly, and those with weakened immune systems.
The study used mice to show how S. pneumoniae has evolved to give off a toxin called pneumonlysin, which causes a strong inflammatory immune reaction in airways resulting in increased nasal secretions that allow cells lining mucous membranes to release the bacteria.
"Factors that allow for the host-to-host transmission of disease-causing bacteria have not been thoroughly investigated by the field as a means of prevention," Dr. Jeffrey Weiser, chair of the Department of Microbiology at NYU Langone, said in a press release. "Our findings provide evidence of the tool used by these bacteria to spread, which promises to guide the design of new kinds of countermeasures."
Researchers found that when pneumonlysin toxin is emitted, S. pneumoniae "gets creative" in finding nutrients and exiting the current host. The toxin can induce a strong response from the body because it drills pores into cells to get the nutrients to sustain them while they are traveling outside the body.
They then exit the body whose immune system is attacking them through the toxin-induced secretions to find a new host.
"Our study results argue that toxins made by bacteria are central mediators of transmission between hosts, which makes them attractive as a potential ingredient in vaccines, to which they could be added specifically to block transmission," Weiser said. "There are precedents in using disarmed bacterial toxins, or toxoids, as vaccine ingredients, as with existing vaccines against diphtheria, tetanus and pertussis."
The study was published in Cell Host & Microbe.