Mucoid strains of Pseudomonas aeruginosa produce a viscid slime when grown on the surface of agar media. These strains are known to colonize persistently the tracheobronchial tree of children with cystic fibrosis. Colonization may result from inhibition of phagocytosis due to slime produced by the organism. Slime separated from one mucoid strain was examined to determine whether it possessed antiphagocytic activity in vitro. Cells of P. aeruginosa, Escherichia coli, and Staphylococcus aureus were rapidly phagocytized by rabbit polymorphonuclear leukocytes when mixtures were rotated for 2 hr at 37 C in the absence of slime. The addition of relatively small amounts of slime to bacteria and leukocytes inhibited phagocytosis as measured by phagocytic killing of the organisms. Inhibition was found to be most complete with P. aeruginosa.

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While diarrheal disease is a well-recognized problem in children, its impact in the elderly has not been adequately assessed. Among the 4.06 million hospitalizations in 1985 in the McDonnell-Douglas Health Information System database, 98,185 hospitalizations, including 1,130 deaths, had gastroenteritis recorded as a discharge diagnosis. The authors analyzed the 87,181 hospitalizations and 514 deaths for which gastroenteritis was one of the top three diagnoses. Gastroenteritis was among the top three diagnoses in 9% of all hospitalizations of children 1-4 years of age, compared with 1.5% of hospitalizations throughout adulthood (greater than or equal to 20 years). Only 0.05% of hospitalizations involving gastroenteritis were fatal for children younger than 5 years, compared with 3% in individuals 80 years or older. While children aged less than 5 years and adults aged 60 years or more each comprised one-fourth of hospitalizations involving gastroenteritis, the older group represented 85% of diarrheal deaths. Age was the most important risk factor for death subsequent to a hospitalization involving gastroenteritis (odds ratio = 52.6, 95% confidence interval 37.0-76.9 for age greater than or equal to 70 years vs. less than 5 years). Gastroenteritis is a large, underemphasized public health problem among the elderly, among whom its case-fatality ratio is higher than in children.

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