[Correlation of endotracheal tube biofilm and recurrent ventilator-associated pneumonia with Pseudomonas aeruginosa].

OBJECTIVE

To determine the correlation of endotracheal tube biofilm (ETT-BF) and recurrent ventilator-associated pneumonia with Pseudomonas aeruginosa (PA-VAP) in long-term ventilation patients.

METHODS

Pulsed-field gel electrophoresis (PFGE) of Spe I enzyme-restricted chromosomal DNA was performed to identify the DNA patterns of Pseudomonas aeruginosa from ETT-BF, pharynx and lower respiratory tract secretion in 15 VAP patients. The chromosomal DNA fingerprint profile of each strain was compared with those from all other strains to calculate the similarity by using the correlation coefficient. The strains were then grouped and groups were depicted as a dendrite using the average clustering algorithm.

RESULTS

When bacteria has been isolated from ETT-BF, the same DNA pattern species are isolated from the lower respiratory tract secretion in 7 of 15 patients. Recurrent PA-VAP is caused by closely related and indistinguishable isolates in 6 of 15 patients. All PEGE patterns from 9 patients are different from one another (correlation coefficient < 31.2%).

CONCLUSIONS

The close pathogenic relationship between ETT-BF and lower airway secretion suggests that adhesive colonization of ETTs may be an important factor in the pathogenesis of VAP.