Experimental vaccine developed to combat hospital-acquired infections
Vaccination before hospitalization would prevent antibiotic-resistant infections.Researchers at the University of Southern California have developed a new type of vaccine that can be administered to patients upon arrival at the hospital to prevent them from contracting a wide range of infections during treatment. The vaccine does not target specific bacteria, but activates cells of the innate immune system.
Most vaccines stimulate the acquired immune system to produce antibodies that target a specific pathogen. The vaccine proposed to treat hospital-acquired infections instead activates the innate immune system to increase the production of macrophages.
These immune cells are found in all tissues of the body, finding and destroying foreign organisms such as bacteria and fungi. By affecting the immune system as a whole rather than a specific pathogen, the vaccine's potential range of applications is broadened. "Otherwise, multiple vaccines would have to be administered simultaneously to protect against the full spectrum of antibiotic-resistant microbes," says Brian Luna, co-author of the study.
The vaccine was tested on mice in two independent laboratories. Analysis showed that the level of macrophages in the animals' bloodstream increased significantly. This protected them from blood or lung infections caused by multiple drug-resistant strains of bacteria, including Staphylococcus aureus, E. coli, enterococcus and others, as well as fungi that cause candidiasis.
The researchers found that a single dose of the vaccine begins to take effect within 24 hours and is effective for up to 28 days, after which a second dose can be administered to restore effectiveness. The vaccine consists of three ingredients: aluminum hydroxide, monophosphoryl lipid A and a fragment of a common skin fungus. The first two ingredients are already used in approved vaccines. Clinical trials should confirm the safety and efficacy of the new prophylaxis method.