A prospective study of swimming-related illness. I. Swimming-associated health risk.

During the summer of 1980, both swimmers and nonswimmers were enlisted in a prospective epidemiological study to determine the relationship between swimming, water quality, and the incidence of illness. Results of 4,537 telephone follow-up interviews showed that crude morbidity rates were 69.6 per 1,000 swimmers versus 29.5 per 1,000 nonswimmers. Swimmers experienced respiratory ailments most frequently, followed by gastrointestinal, eye, ear, skin, and allergenic symptoms, respectively.

A prospective study of swimming-related illness. II. Morbidity and the microbiological quality of water.

A prospective cohort epidemiological-microbiological study was carried out at 10 beaches in Ontario, Canada. Lake water and sediment samples collected at the beaches were analyzed for fecal coliforms, fecal streptococci, heterotrophic bacteria, Pseudomonas aeruginosa, and total staphylococci. Mean fecal coliform levels in the surface water of the lakes were within accepted guidelines. Bacterial densities were found to be approximately 10 times higher in the sediment than in the corresponding surface water samples. Morbidity among swimmers was shown to be related to staphylococcal counts, to fecal coliform levels, and, somewhat less strongly, to fecal streptococcal counts. Total staphylococci appeared to be more consistent indicators for predicting total morbidity rates among swimmers.

Persistence of Pseudomonas aeruginosa in chlorinated swimming pools.

Various types of swimming pools were investigated for the quantitative isolation of Pseudomonas aeruginosa. Incidence of the organism increased when the free chlorine residual dropped below 0.4 mg/L in pool water which ad a pH of 6.9-8.9. As the water pH became more alkaline the efficiency of disinfection decreased. Excessive slime production caused certain strains to become more resistent to chlorine treatment. Immunotyping and phage typing, used to study the dynamics of P. aeruginosa populations in swimming pool waters, demonstrated that high densities of the organism consisted mainly of single predominant strains.

Pseudomonas aeruginosa in swimming pools related to the incidence of otitis externa infection.

A study is reported which demonstrates that four out of twenty-four people developed otitis externa as a result of swimming in a pool with a high incidence of Pseudomonas aeruginosa. Serotyping and phage typing were used to establish that P. aeruginosa was the etiolgoical event responsible for the outbreaks of the infection.

Numerical taxonomy of aquatic Acinetobacter isolates.

Two hundred and seventy Gram-negative strains, representing aquatic members of the genus acinetobacter, were isolated and compared with 48 related clinical isolates and reference strains from a variety of genera. For each isolate, a total of 96 coded characters derived from 89 characteristics was determined using morphological, physiological, nutritional and biochemical features, in addition to sensitivities to several antibiotics and inhibitory agents. The data were analysed by computer to obtain a simple matching coefficient for each pair of strains. Clustering was performed by the unweighted pair-group method of association. Two major phenons were formed which excluded the oxidase-positive, motile or facultatively anaerobic strains. Within each phenon, three 'subphenons' were delimited. The two phenons, comprising 291 isolates, were tentatively differentiated at the species level, while their shared characteristics indicated that both phenons should be included in the genus Acinetobacter. Phenon 2 contained most of the clinical isolates and corresponded to the type species Aci. calcoaceticus as described originally by Baumann, Doudoroff & Stanier (1968). Phenon 1 was composed almost entirely of aquatic isolates and may prove to represent a second species of a less biochemically-active nature. Distinguishing characters have been suggested as diagnostic criteria for the differentiation of these two phenons.