Oropharyngeal flora in patients admitted to the medical intensive care unit: clinical factors and acid suppressive therapy

Abstract

Acid suppression therapy in critically ill patients significantly reduces the incidence of stress ulceration and gastrointestinal (GI) bleeding; however, recent studies suggest that proton pump inhibitors (PPIs) increase the risk of pneumonia. We wanted to test the hypothesis that acid suppressive therapy promotes alteration in the bacterial flora in the GI tract and leads to colonization of the upper airway tract with pathogenic species, potentially forming the biological basis for the observed increased incidence of pneumonia in these patients. This was a prospective observational study on patients (adults 18 years or older) admitted to the medical intensive care unit (MICU) at a tertiary care centre. Exclusion criteria included all patients with a diagnosis of pneumonia at admission, with infection in the upper airway, or with a history of significant dysphagia. Oropharyngeal cultures were obtained on day 1 and days 3 or 4 of admission. We collected data on demographics, clinical information, and severity of the underlying disease using APACHE II scores. There were 110 patients enrolled in the study. The mean age was 49±16 years, 50 were women, and the mean APACHE II score was 9.8±6.5. Twenty per cent of the patients had used a PPI in the month preceding admission. The first oropharyngeal specimen was available in 110 cases; a second specimen at 72–96 h was available in 68 cases. Seventy-five per cent of the patients admitted to the MICU had abnormal flora. In multivariate logistic regression, diabetes mellitus and PPI use were associated with abnormal oral flora on admission. Chronic renal failure and a higher body mass index reduced the frequency of abnormal oral flora on admission. Most critically ill patients admitted to our MICU have abnormal oral flora. Patients with diabetes and a history of recent PPI use are more likely to have abnormal oral flora on admission.