The characteristics of bacterial biofilm formation in endotracheal tubes in ventilated patients and the relationship between the biofilm and ventilator-associated pneumonia

Abstract

Objective To observe the formation of the biofilm in endotracheal tubes, the characteristics of etiology, drug resistance and relationship between the biofilm and ventilator-associated pneumonia(VAP). Methods A total of 60 cases of ventilated children patients whose mechanical ventilation time were ≥48 h in the ICU from September 2010 to September 2012, according to the mechanical ventilation time, all cases were divided into 2 to 6 d group, 7 to 14 d group and ≥15 d group.The incidence of VAP, biofilm structure under the electron microscope, etiology culture positive rate of the lower airway secretions and biofilm, etiological characteristics and drug resistance were prospectively studied. Results (1) A total of 19 cases occurred VAP in 60 cases of mechanical ventilation, the incidence of VAP was 31.7%.(2) Observed by electron microscope, biofilm had formed in the endotracheal tube inner wall in early period of mechanical ventilation.With prolonged mechanical ventilation, biofilm structure had improved, as well as VAP incidence rate from 9.1%(2 to 6 d group ) increased to 44.4%(7 to 14 d group) and 88.9%(≥15 d group). (3) A large number of pathogenic bacteria colonized in the biofilm.Gram-negative bacilli were dominate and drug resistance was high.(4) With prolonged mechanical ventilation, the cultured pathogens from the lower airway secretions and biofilm converged. Conclusion Biofilm could form in the endotracheal tube with mechanical ventilation patients, and is associated with the occurrence of VAP and refractory infections. Key words: Endotracheal tube; Biofilm; Ventilator-associated pneumonia; Pathogens; Drug resistance