New research published in The Journal of Infectious Diseases describes how a team in the US has developed a new vaccine that protects against lethal staph-induced pneumonia.

Staphylococcus aureus (staph) bacteria causes serious infections in both hospital and community settings, write the researchers.

Led by Patrick Schlievert, a professor at the University of Iowa (UI), the researchers describe a new vaccine that targets three toxins made and secreted by the staph bacteria.

They show that the anti-toxin vaccine almost completely protected lab animals whose lungs were infected with multiple strains of staph resembling those of human infections, including drug-resistant strains like MRSA.

The vaccine protected the animals even when infected with very high doses of bacteria. Not only did it prevent deaths, but 7 days after vaccination, there were no traces of the bacteria in the animals’ lungs.

Previous attempts to prevent human infection have used a vaccine that targets cell-surface antigens or proteins. In the current study, the team showed that using this kind of vaccine actually increases the severity of infection.

The study follows earlier work where Prof. Schlievert, who is chair of microbiology in UI’s Carver College of Medicine, had shown the staph-secreted toxins were responsible for the serious, sometimes fatal, symptoms that result from staph infections, such as high fever, low blood pressure, and toxic shock.

Prof. Schlievert says:

Our study suggests that vaccination against these toxins may provide protection against all strains of staph. If we can translate this finding into an effective vaccine for people it could potentially prevent millions of cases of serious and milder skin and soft tissue infections yearly.”

The researchers also found that using serum from vaccinated animals to protect other animals – something called passive immunization – was also successful, and they suggest this shows that the antibodies induced by the vaccine are the protective factor.

Staph is the most significant cause of serious infections and related deaths in the US, according to the Centers for Disease Control and Prevention (CDC).

Staph infections range from boils and other skin infections to life-threatening pneumonias and sepsis.

Around 70,000 Americans develop staph-induced pneumonia every year, including cases caused by drug-resistant strains like MRSA. Those patients that survive the illness require extensive convalescence.

Grants from the National Institutes of Health helped fund the study.

Another US study published in 2011 found that the rate of staph pneumonia in children has doubled in the last decade.