Pneumonia is a common complication in patients on breathing machines and occurs when harmful bacteria from the mouth, throat or breathing tube are inhaled into the lungs.
The journal Critical Care reported that the probiotic solution performed just as well as normal antiseptics, which are used to keep pneumonia-causing bacteria at bay.
Since it is more natural it could pose fewer side effects, the experts said.
Patients swabbed with probiotic bacteria called Lactobacillus plantarum 299 escaped infection as well as those cleaned up using the antiseptic chlorhexidine, they reported.
Both approaches worked equally well in preventing pneumonia among 50 critically ill patients using ventilators, Bengt Klarin of University Hospital in Lund, Sweden, and colleagues found.
In addition, a probiotic that adheres to mouth lining will be able to work around the clock, unlike antiseptics, which wear off after a few hours, say the authors.
"This is a plausible idea. But we need much larger trials that focus on clinical outcomes to prove it is an effective and affordable treatment," BBC quoted Bob Marsterton, chair of the British Society for Antimicrobial Chemotherapy's working party on hospital acquired pneumonia, as saying.