Hospitals are supposed to be places where diseases are cured, but patients often contract new illnesses there that are potentially dangerous and difficult to treat. A new experimental vaccine that can be injected when patients are admitted to hospital could help prevent infections from a range of drug-resistant bacteria and fungi by activating another branch of the immune system.
With so many patients crammed together, it’s no surprise that nosocomial infections occur. The bacteria there are frequently exposed to antibiotics, and many develop resistance and are then spread to new patients through doctors' hands or medical equipment. These infections can be fatal, especially in intensive care patients or patients with weakened immune systems.
To prevent these infections, scientists at the University of Southern California (USC) have now developed a new vaccine that can be given to patients when they are admitted to the hospital, preventing them from contracting various diseases while they are in the hospital.
Most vaccines work by stimulating the adaptive immune system to produce antibodies against specific pathogens. But the new vaccine works differently, activating the innate immune system and promoting the production of immune cells called macrophages. Macrophages are found in all tissues of the body and can detect and destroy foreign invaders such as bacteria and fungi, making the vaccine potentially broad-spectrum rather than targeting just one target.
"[Otherwise], multiple vaccines would have to be used simultaneously to protect against all antibiotic-resistant microorganisms that cause hospital-acquired infections," said study author Brian Luna.
Two independent laboratories tested the vaccine on mice and found significantly higher levels of macrophages in the animals' blood. This protects them against blood or lung infections from multiple drug-resistant strains of MRSA, E. coli, Enterococcus faecalis, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa, as well as common fungi Rhizopus and Candida albicans.
A single dose of the vaccine starts working within 24 hours and lasts up to 28 days.重要的是，这种疫苗由三种成分组成：氢氧化铝、单磷脂A--这三种成分已被美国食品及药物管理局批准用于人类疫苗，另外还有一种常见皮肤真菌的片段。
The team said the vaccine could help prevent death and illness from hospital infections and slow the development of antibiotic resistance because fewer antibiotic drugs would be needed. The next step toward achieving this goal will be human clinical trials, which the researchers plan to conduct next with help from the U.S. Food and Drug Administration.
The research was published in the journal Science Translational Medicine. The research team describes the work in the video below.