Oropharyngeal Gram-negative bacillary carriage in chronic obstructive pulmonary disease: relation to severity of disease

The prolonged presence of aerobic Gram-negative bacilli (AGNB) in the oroph arynx is termed 'carriage'. AGNB carriage rates are low in populations of h ealthy individuals. Previously, severity of underlying disease has been pos itively correlated with oropharyngeal AGNB carriage rate. Overgrowth of AGN B at the oropharynx poses a significant risk of endogenous infection in end -stage chronic obstructive pulmonary disease (COPD) patients. The aims of t his study were to undertake an epidemiological survey of the oropharyngeal flora of COPD patients and to correlate oropharyngeal carriage of AGNB with severity of disease. Two oral rinses were obtained, within a 2-day interval, from 40 COPD patien ts comprising three disease severity groups: 1. mild, 2. moderate and 3. se vere. Eighty oral rinses were quantitatively (1:10 dilution series) culture d for AGNB and yeasts using broth enrichment. The mean AGNB carriage rate was 15%. AGNB carriage rates of 0, 7.7 and 29.4 % were observed within the mild, moderate and severe disease groups, respec tively. The mean yeast carriage rate was 33.3%. Yeast carriage rates of 33. 3, 15.4 and 64.7% were observed within the mild, moderate and severe diseas e groups, respectively. Carriage of Staphylococcus aureus was 5%. Rates of oropharyngeal carriage of AGNB (1/23 vs. 5/17) and yeasts (5/23 vs. 11/17) were significantly higher within the severe disease group than in non-sever e disease groups. Oropharyngeal carriage of AGNB in end-stage COPD patients (forced expirator y volume in 1 sec, FEV1 < 50% predicted) presents a potential source of Gra m-negative endogenous pneumonia. This outcome may be promoted by intubation and some flora-suppressing antibiotic therapies. (C) 1999 Harcourt Publish ers Ltd.