Pattern of tracheal colonization during mechanical ventilation.

Abstract

The relationship between gastric (GC) and tracheal (TC) colonization and the development of ventilator-associated pneumonia (VAP) remains controversial. TC, GC, and pharyngeal (PC) colonization were studied serially in 80 patients with mechanical ventilation (MV) to ascertain the routes and onset of TC. Simultaneous sample from pharynx, stomach, and trachea were obtained throughout the MV period. Quantitative cultures were performed. Seventy-two patients (90%) had TC at some time during MV. Only 19 patients presented TC after PC or GC by the same microorganisms. Indigenous gram-negative and gram-positive microorganisms colonized mainly the trachea from the start of or during MV without previous PC or GC (p < 0.05). Pseudomonas were the microorganisms causing TC principally during MV without previous PC or GC (p < 0.005). Enterobacteria produced TC without a preferential route. Of the 12 patients who developed VAP, the microorganisms responsible had already colonized the trachea in 10 patients. Only 10 of the 21 microorganisms isolated in VAP had previously colonized the pharynx or stomach. In summary, although some microorganisms have preferential routes for producing TC, the microorganisms isolated frequently change during MV. TC precedes VAP in most patients, but only a minority develop a VAP; therefore, together with TC other factors must be involved in VAP development.

Pathophysiology of Escherichia coli ventilator-associated pneumonia: implication of highly virulent extraintestinal pathogenic strains

“…Because of the specific aims of our study and therefore its design, comparison with existing data is difficult. However, our results expand those previously published dealing with GNB colonization, indicating increasing levels of colonization with increasing patient severity and subsequent risk for VAP [37][38][39].…”

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

“…The following data were recorded in each case: age and sex of the patient, reasons for mechanical ventilation, type of humidification used (humidifier in the ventilator circuit or heat and moisture exchanger), duration of ventilation, means of respiratory access (oral or nasal ETT or tracheostomy), method of stress ulcer prophylaxis (histamine type 2-receptor blockers or barrier preparation, i.e. sucralfate), the occurrence or not of nosocomial pneumonia, together with data of suspected nosocomial pathogens, using criteria similar to those previously described [10,11].…”

“…L -1 ; 4) purulent tracheobronchial secretions; and 5) no evidence of infection elsewhere. Organisms cultured in significant amounts (2+ (20±100 colonies) and 3+ (>100 colonies) growth) from good quality specimens of secretions obtained by sterile suctioning of the lower respiratory tract through the ETT or tracheostomy tube were considered to be likely causative pathogens, as previously described [10].…”

Initial Bacterial Colonization in Patients Admitted to a Respiratory Intensive Care Unit:Bacteriological Pattern and Risk Factors

“…In a study by de Latorre et al [13]64 of 80 patients (80%) showed colonization of the trachea within the first 24 h of mechanical ventilation. In a selected cohort of patients with severe exacerbation of chronic obstructive pulmonary disease, bacterial colonization of 72% during the 1st day of mechanical ventilation was reported [14].…”