A probiotic bacterium reduces hospital infections

A probiotic bacterium, Lactobacillus plantarum 299, has been used to out-compete the dangerous bacteria that cause respiratory illness in ventilated patients.

Research published in BioMed Central's open access journal Critical Care describes how applying a bacterial solution in place of normal antiseptics is effective in preventing the most common cause of ventilator-associated pneumonia (VAP).

Bengt Klarin from the University Hospital in Lund, Sweden, led a team of researchers who carried out a randomised, controlled trial in fifty patients, comparing friendly bacteria to the normally used antiseptic chlorhexidine (CHX). Klarin said, "We hypothesised that swabbing the mouth with probiotics would be an effective (and microbiologically attractive) method of reducing pathogenic oral microorganisms in intubated, mechanically ventilated, critically ill patients."

VAP is a common complication in patients on breathing machines. It occurs when harmful bacteria from the mouth, throat or breathing tube are inhaled into the lungs. Because most people on ventilation are sedated or unable to communicate, initial symptoms of pneumonia can be difficult to spot. According to Klarin, "VAP is connected with longer intensive care and hospital stays, additional costs and high mortality. The risk of developing this condition increases by 1% with each additional day of mechanical ventilation."

The authors found that the probiotic treatment was as effective as the antiseptic. Use of the bacteria has other advantages; there are common side effects associated with CHX use in oral care, including tooth discoloration, irritation and, very occasionally, serious allergic reactions. Moreover, CHX diluted by saliva and represents an additional risk for the creation of resistant strains. The authors claim that the L. plantarum 299 solves these problems, "It is not likely to incorporate resistance genes or plasmids or to transfer genetic material. Consequently it does not contribute to the development of antibiotic-resistant strains. As the bacteria adhere to the oral mucosa, they are able to counteract potentially pathogenic bacteria around the clock, which is superior to the fairly short-term effect of orally applied chemical agents."

L. plantarum is normally present in saliva and is also commonly found in fermented food products like pickles and sauerkraut. The authors found no negative side effects of using it in this study.