Oropharyngeal gram-negative bacillary carriage - A survey of 120 healthy individuals

Background: The presence of aerobic Gram-negative bacilli (AGNB) in the oro pharynx can be either temporary or persistent, Prolonged colonization (ie, carriage) is distinguished from transient presence (ie, acquisition), which often occurs in healthy individuals hut less frequently in those with unde rlying disease, Prevalence rates of up to 61.1% quoted previously for healt hy individuals were obtained by using single sample surveys, which fail to differentiate acquisition from carriage, Study objectives: To illustrate the need to distinguish carriage from acqui sition in a healthy population at risk of acquisition of AGNB, and to show that although differing groups of healthy individuals may acquire oropharyn geal AGNB at differing frequencies, carriage is rare in healthy individuals . Participants: Two oral rinses were obtained within a 2-day interval from 12 0 healthy individuals comprising 40 nurses, 40 students, and 40 laboratory- associated persons. Design: Two hundred forty oral rinses were quantitatively (1:10 dilution se ries) cultured for AGSB by using broth enrichment. Measurements and results: The rate of AGNB carriage based on two consecutiv e samples positive for the same AGNB was 6.6%; the rate of AGNB acquisition based on one positive sample was 35.8%. The concentrations of all carried and acquired. AGNB were less than or equal to 103 cfu/mL. AGNB acquisition was significantly higher in students (52.5%) compared to nurses (32.5%) and laboratory-associated persons (22.5%; p < 0.05), Conclusion: Healthy individuals rarely carry oropharyngeal AGNB, suggesting effective oropharyngeal clearance in a healthy population predisposed to a cquisition, Apparently, the oropharyngeal mucosa in healthy individuals is not receptive to adhesins of AGNB, resulting in rapid elimination of these bacteria.