Background: Pathogenic enteric bacteria aspirated from the oropharynx are the main cause of ventilator-associated pneumonia (VAP). Using chlorhexidine (CHX) orally or selective decontamination has been shown to reduce VAP. In a pilot study we found that oral care with the probiotic bacterium Lactobacillus plantarum 299 (Lp299) was as effective as CHX in reducing enteric bacteria in the oropharynx. To confirm those results, in this expanded study with an identical protocol we increased the number of patients and participating centres.
Methods: One hundred and fifty critically ill patients on mechanical ventilation were randomised to oral care with either standard 0.1% CHX solution (control group) or a procedure comprising final application of an emulsion of Lp299. Samples for microbiological analyses were taken from the oropharynx and trachea at inclusion and subsequently at defined intervals. Student's t test was used for comparisons of parameters recorded daily and Fisher's exact test was used to compare the results of microbiological cultures.
Results: Potentially pathogenic enteric bacteria not present at inclusion were identified in oropharyngeal samples from 29 patients in the CHX group and in 31 samples in the probiotic group. Considering cultures of tracheal secretions, enteric bacteria were found in 17 and 19 samples, respectively. Risk ratios show a difference in favour of the Lp group for fungi in oropharyngeal cultures. VAP was diagnosed in seven patients in the Lp group and in 10 patients among the controls.
Conclusions: In this multicentre study, we could not demonstrate any difference between Lp299 and CHX used in oral care procedures regarding their impact on colonisation with emerging potentially pathogenic enteric bacteria in the oropharynx and trachea.
Trial registration: ClinicalTrials.gov, NCT01105819 . Registered on 9 April 2010. First part: Current Controlled Trials, ISRCTN00472141 . Registered on 22 November 2007 (published Critical Care 2008, 12:R136).
Keywords: Chlorhexidine; Lactobacillus plantarum 299; Mechanically ventilated patients; Oral care; Probiotics; Resistance to antibiotics; Ventilator-associated pneumonia.