Antibiotic resistant bacteria already cause tens of thousands of fatal infections every year, and that number is expected to continue to rise. Even while many commonly used antibiotics are becoming less effective, few new ones are being created. Developing new antibiotics is also challenging and costly. Scientists have now discovered human antibodies that could change how we deal with bacterial infections that are caused by pathogenic Pseudomonas aeruginosa microbes. Many P. aeruginosa infections are complicated, and they can be fatal to patients when sepsis occurs. These new, "highly neutralizing" antibodies, which were isolated from patients, could be a major step forward in the fight against some antibiotic resistant microbes. The findings have been reported in Cell.
Some strains of P. aeruginosa have multiple ways to resist the effects of antibacterial drugs, and these complex infections can be particularly tough to treat because they can take up residence in the lungs permanently, continuously causing tissue damage.
In this work, the investigators analyzed whether human antibodies could be used to target bacteria, an approach that is usually used against viruses. They isolated antibodies from the immune cells of cystic fibrosis patients who had chronic P. aeruginosa infections.
"Many of the therapeutic antibodies that are already being used against viruses have been isolated and developed from infected, recovered, or vaccinated individuals," noted lead study author Dr. Alexander Simonis of University Hospital Cologne.
The antibodies isolated in this study were found to block a crucial bacterial virulence factor called the type III secretion system, which has a role in severe P. aeruginosa infections. With cell culture and animal models, the investigators also showed that these antibodies can stop pathogenic P. aeruginosa as well as standard drugs. The antibodies don't use the same mechanisms as standard drugs to stop bacteria, however. As such, they may be effective against drug resistant bacteria too.
"The findings and the experimental approaches can also be transferred to other bacterial pathogens and thus represent a promising new approach for the treatment of infections with multi-resistant bacteria," noted senior study author Dr. Jan Rybniker of University Hospital Cologne.
Now, the researchers are refining the antibodies so they can be tested in clinical trials. They are hopeful that these antibodies can be used in the clinic to help patients with severe P. aeruginosa infections. The antibodies might also be useful as a preventive medicine for patients in intensive care or with compromised immune systems.
Sources: University of Cologne, Cell
