The presence and sequence of endotracheal tube colonization in patients undergoing mechanical ventilation

Abstract

Endotracheal tube colonization in patients undergoing mechanical ventilation was investigated.In the first part of this prospective study, the airway access tube was examined for the presence of secretions, airway obstruction and bacterial colonization, in cases undergoing extubation or tube change. In the second part of the study, the sequence of oropharyngeal, gastric, respiratory tract and endotracheal tube colonization was investigated by sequential swabbing at each site twice daily for 5 days in consecutive noninfected patients.In the first part, it was noted that all airway access tubes of cases undergoing extubation had secretions lining the interior of the distal third of the tube which were shown on scanning electron microscopy to be a biofilm. Gram-negative micro-organisms were isolated from these secretions in all but three cases. In the second part, it was noted that the sequence of colonization in patients undergoing mechanical ventilation was the oropharynx (36 h), the stomach (36±60 h), the lower respiratory tract (60±84 h), and thereafter the endotracheal tube (60±96 h). Nosocomial pneumonia occurred in 13 patients and in eight cases identical organisms were noted in lower respiratory tract secretions and in secretions lining the interior of the endotracheal tube.The endotracheal tube of patients undergoing mechanical ventilation becomes colonized rapidly with micro-organisms commonly associated with nosocomial pneumonia, and which may represent a persistent source of organisms causing such infections. Eur Respir J 1999; 13: 546±551.

Risk factors for Hospital-Acquired Pneumonia in nonventilated adults

“…The pathogenesis of VAP and NVHAP may differ in several ways. Feldman et al documented the rapid development colonization in the oropharynx, stomach, lower airways and endotracheal tube in patients under mechanical ventilation [20]. The dynamics of colonization is dependent on the extensive and aggressive manipulations to which those patients are exposed.…”

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

“…One study demonstrated that 84% of endotracheal tubes examined had a biofilm (188). As documented by Inglis et al, this biofilm is heavily laden with bacteria, usually gram-negative organisms (66,89). At present, ongoing studies are directed at either eliminating this biofilm or reducing the bacterial load associated with it.…”

Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia

“…Previous studies have reported a high concordance of bacterial culture results between tracheal aspirate samples and ET biofilms (8,23). For example, in a previous study conducted among adults undergoing mechanical ventilation in Spain, identical microorganisms with ET biofilms were isolated in 56% of tracheal aspirate samples (8).…”

“…in ET biofilms. Feldman et al (23) reported the time sequence of bacterial colonization in VAP patients, and demonstrated that potential pathogens first colonized the oropharynx and then the lower respiratory tract. Therefore, there may be a high consistency of bacteria between oropharynx and ET biofilms in the early stages of VAP.…”