Gastric and Pharyngeal Flora in Nosocomial Pneumonia Acquired during Mechanical Ventilation

Abstract

We studied the interrelations between gastric, pharyngeal, proximal, and distal airway bacterial flora in ventilator-associated pneumonia (VAP) on 36 patients with nosocomial pneumonia acquired during mechanical ventilation (MV) and 27 mechanically ventilated control subjects without pulmonary infection. Gastric, pharyngeal, and endotracheal (EA) sampling for quantitative cultures were performed upon all patients, as well as fiberoptic bronchoscopy with protected specimen brush (PSB) sampling. Mean bacterial and fungi colony counts were significantly increased in pharyngeal, EA, and PSB samples in patients with VAP compared with control subjects. The overall increase in colonization was due to gram-positive cocci in all samples. In addition, gram-negative bacilli and fungi mean counts increased significantly in PSB pneumonia samples versus control samples. However, mean gastric colonization was similar in both patients with VAP and control subjects. In the former group there was an increase in coincident microorganisms isolated from gastric, pharyngeal, and EA samples in relation to PSB samples compared with control samples. Among the different quantitative cultures analyzed, only those obtained from EA significantly correlated with PSB cultures in patients with pneumonia (r = 0.67, p = 0.001). In summary, the present study shows that the coincidence between microorganisms isolated in PSB cultures and those from gastric and oropharynx increase in MV patients with pneumonia, indicating that both reservoirs play a key role in the pathogenesis of pneumonia. Conceivably, preventing both gastric and pharyngeal colonization may reduce the incidence of ventilator-associated pneumonia. From all the noninvasive samples studied only endotracheal aspirate cultures were useful for inferring the etiology of some VAP pneumonias.

Comparison of a Novel Lycra Endotracheal Tube Cuff to Standard Polyvinyl Chloride Cuff and Polyurethane Cuff for Fluid Leak Prevention

“…12,13 Early-onset VAP seems mostly derived from Gram-positive oral bacteria, whereas late-onset VAP is from multi-resistant Gram-negative bacteria from the gut. 12,14 Some bacteria enter the trachea during intubation, but it is reasonable to assume that the bulk of bacteria that cause VAP come from leakage of subglottic secretions past the ETT cuff.…”

Molecular Evidence that Nasal Carriage of Staphylococcus aureus Plays a Role in Respiratory Tract Infections of Critically Ill Patients

“…Several studies focused on the link between S. aureus nasal carriage, oropharyngeal and tracheal colonization, and pneumonia, but the majority used phenotypic markers such as serotyping or antibiotic susceptibility testing (1,3,4,8,18). As shown in this study, antibiotyping is often inadequate for differentiating strains.…”

Anaesthesiology and intensive care Possibilities of modification of risk factors for ventilator-associated pneumonia (VAP) in cardiac surgery patients

“…Colonization of the oropharyngeal cavity by microorganisms is considered to be an independent risk factor of VAP [35,36]. One of the methods of reducing this risk is the local use of antiseptics or antibiotics; it should, however, be emphasized that these measures, while reducing VAP incidence, facilitate patient colonization by multidrug-resistant (MDR) pathogens [8,37].…”