New Targets Now a Possibility for Fighting Pseudomonas aeruginosa Infection

Researchers have discovered that a higher presence of neutrophils at infection sites leads to a greater density of biofilm, which increases the rate of the infection, findings that may lead to new treatment strategies.

Scientists from several organizations in Colorado specifically looked at chronic infection by Pseudomonas aeruginosa (P. aeruginosa) in the airways of cystic fibrosis (CF) patients and health volunteers.

In all ratios of bacteria to neutrophils that were taken, there was “a significant enhancement of biofilm density when compared to P. aeruginosa of equal concentration grown in the absence of neutrophils,” according to the study article that appeared in the Journal of Medical Microbiology.

When neutrophils attack P. aeruginosa, the contents of the cell are released. Those contents are then used by the bacterium to create a scaffold, which then encloses the infection site in a biofilm and makes treatment much more difficult.

These biofilms can cause infections in burns, wounds, infections that result from the use of contact lenses, and are highly prevalent in the lungs of CF patients, according to the EurekAlert!.

Though the Microbiology publication describes many different ways in which the formation of the biofilm could be disrupted or impaired, there were only two instances where P. aeruginosa biofilms were halted.

“Negative poly(amino acid) chains possess capacity to prevent neutrophil-induced enhancement of P. aeruginosa biofilm formation,” according to the journal article. The researchers discussed two specific short amino acid chains — (Asp)74 and (Ser)74 — that led to a lack of biofilm formation.

In addition, the journal article also explained that “neutrophil-induced P. aeruginosa biofilms are both disrupted and prevented by DNase.”

The targets that the researchers used to impact the formation of the biofilms, a negatively charged peptide and the enzyme DNase, “both prevented and disrupted the formation of P. aeruginosa biofilms in the presence of human neutrophils," said Dr. Quinn Parks, who works in the Department of Medicine at National Jewish Health in Denver and is lead author of the study. "These results suggest a new combined therapeutic strategy for the treatment of P. aeruginosa infections.”