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J E Stout

Publications and source records attributed to J E Stout.

51 records · Page 3Linked to original sources
PubMed1992

Legionella pneumophila in residential water supplies: environmental surveillance with clinical assessment for Legionnaires' disease.

Although cases of community-acquired Legionnaires' disease have been epidemiologically linked to residential water supplies, the risk of acquiring Legionnaires' disease from exposure to Legionella pneumophila in residential water systems is uncertain. The residential water supplies of 218 members of the American Legion in six different geographical areas in Pittsburgh were cultured for L. pneumophila. Residents of the homes provided a recent medical history and a blood sample for detection of antibodies to legionella. A urine sample for legionella urinary antigen testing was also requested from individuals residing in legionella-positive homes and individuals with a positive antibody test. Six percent (14/218) of the homes yielded L. pneumophila (range within six areas 0-22%). Lower hot water tank temperature was significantly associated with legionella positivity (P less than 0.01). Analysis of water samples for mineral content showed no association between legionella positivity and concentrations of calcium and magnesium. Water samples from the area where 22% of the homes surveyed were positive for legionella had a higher iron content than water samples from the other areas tested. None of the individuals residing in legionella-positive homes showed elevated antibody titres to legionella or the presence of legionella antigen in urine. For the immunocompetent hosts, the risk of contracting Legionnaires' disease from exposure to contaminated household water supplies in the Pittsburgh area appears to be low.

Adult↗
PubMed1991

Legionellosis.

Legionella is a common cause of community- and hospital-acquired pneumonia. New information on the pathogenesis of infection and the host immune response is reviewed. Specialized laboratory tests, especially culture, are necessary for diagnosis since the clinical presentation is nonspecific. New antimicrobial agents and innovative approaches to disinfection of water distribution systems are presented.

Disinfection↗
PubMed1990

Failure of a diagnostic monoclonal immunofluorescent reagent to detect Legionella pneumophila in environmental samples.

Three commercial diagnostic fluorescein-labeled antibodies, one monoclonal and two polyclonal, were compared to evaluate their abilities to detect Legionella pneumophila in environmental samples. The monoclonal conjugate failed to detect L. pneumophila in the 12 environmental samples studied by direct immunofluorescence. In contrast, the two polyclonal conjugates detected L. pneumophila in all 12 samples by both direct and indirect immunofluorescence. However, isolates recovered by culture from the 12 samples demonstrated equal immunofluorescence with all three conjugates. The reason for the failure of the monoclonal antibody to detect L. pneumophila in the environmental samples remains unknown. Laboratories considering the use of the monoclonal conjugate to screen environmental samples for L. pneumophila should be aware of this finding.

Antibodies, Bacterial↗
PubMed1988

Legionnaires' disease in the work environment: implications for environmental health.

Legionnaires' disease is a severe pneumonia caused by the bacterium Legionella pneumophila. Outbreaks of Legionnaire's disease have occurred in hotels, hospitals, and homes but had not been reported yet in the work environment. The authors report the occurrence of Legionnaires' disease in three employees of two industrial plants. The potable water in the two plants contained high numbers of Legionella pneumophila. Monoclonal antibody subtyping of environmental and patient isolates of L. pneumophila implicated one of the plants as the source for the disease. L. pneumophila was eradicated from this plant using acidic and caustic scale removers, calcium hypochlorite, and a biocide. A systematic approach to Legionnaires' disease in the work environment, a problem which can be expected to be recognized with increasing frequency, is presented.

Antibodies, Monoclonal↗
PubMed1988

Comparison of molecular methods for subtyping patients and epidemiologically linked environmental isolates of Legionella pneumophila.

We used the molecular techniques of monoclonal antibody typing, plasmid analysis, and outer membrane protein profiling to subtype 159 patients' and environmental (water distribution system) isolates of Legionella pneumophila serogroup 1 from 18 institutions. The ability of these techniques to match patients' and epidemiologically linked environmental isolates from outbreaks of Legionnaires' disease at seven institutions was also compared. Two different panels of monoclonal antibodies (I and II) identified nine subtypes (one new disease-causing subtype) and six subtypes, respectively. The Bellingham 1 subtype type was the most common among environmental isolates, and the Philadelphia 1 subtype predominated among patients' isolates from all institutions except the Veterans Administration Medical Center in Pittsburgh, Pennsylvania. The source of an isolate (patient vs. environment) and its monoclonal antibody subtype were significantly associated (P less than .01). With use of the molecular techniques tested, the subtypes of patients' isolates were identical to those of epidemiologically linked environmental isolates from the same hospital.

Antibodies, Monoclonal↗
PubMed1987

Legionnaires' disease acquired within the homes of two patients. Link to the home water supply.

Two patients with sporadic community-acquired legionnaires' disease are described. Legionella pneumophila was isolated from sputum specimens, and seroconversion of antibody titers was demonstrated for both patients. Legionella pneumophila was also recovered from the residential water supply of both patients. In each case, the serogroup of the environmental organism matched that of the infecting organism. In one patient, serogroup 3 was isolated--a rare cause of legionnaires' disease, and in the second case, monoclonal antibody testing confirmed that the serogroup 1 organisms isolated from sputum and residential water supply samples were identical. The incubation period of legionnaires' disease is presumed to be up to two weeks. Because of medical problems, both patients had been confined to their homes for the entire two weeks before the onset of symptoms. This is the first report that links acquisition of community-acquired legionnaires' disease to contaminated water supplies within the homes of susceptible patients.

Aged↗
PubMed1987

Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system.

Nosocomial Legionnaires disease can be acquired by exposure to the organism from the hospital water distribution system. As a result, many hospitals have instituted eradication procedures, including hypercholorination and thermal eradication. We compared the efficacy of ozonation, UV light, hyperchlorination, and heat eradication using a model plumbing system constructed of copper piping, brass spigots, Plexiglas reservoir, electric hot water tank, and a pump. Legionella pneumophila was added to the system at 10(7) CFU/ml. Each method was tested under three conditions; (i) nonturbid water at 25 degrees C, (ii) turbid water at 25 degrees C, and (iii) nonturbid water at 43 degrees C. UV light and heat killed L. pneumophila most rapidly and required minimal maintenance. Both UV light and heat (60 degrees C) produced a 5 log kill in less than 1 h. In contrast, both chlorine and ozone required 5 h of exposure to produce a 5 log decrease. Neither turbidity nor the higher temperature of 43 degrees C impaired the efficacy of any of the disinfectant methods. Surprisingly, higher temperature enhanced the disinfecting efficacy of chlorine. However, higher temperature accelerated the decomposition of the chlorine residual such that an additional 120% volume of chlorine was required. All four methods proved efficacious in eradicating L. pneumophila from a model plumbing system.

Chlorine↗
PubMed1986

A note on symbiosis of Legionella pneumophila and Tatlockia micdadei with human respiratory flora.

Sixteen micro-organisms, representing clinically important respiratory microflora, were tested for their ability to stimulate the growth of Legionella pneumophila and Tatlockia micdadei in nutritionally-deficient agar media. Nutritional symbiosis, indicated by the appearance of satellite colonies of L. pneumophila or T. micdadei, was observed for H. influenzae and N. meningitidis. This interaction between normal flora and pathogens of the respiratory tract may have clinical relevance in the pathogenesis of Legionnaires' disease and Pittsburgh pneumonia.

Bacterial Physiological Phenomena↗
PubMed1986

Susceptibility of members of the family Legionellaceae to thermal stress: implications for heat eradication methods in water distribution systems.

To ascertain the feasibility of heat inactivation as an eradication method applicable to all members of the family Legionellaceae, we tested the heat resistance of 75 isolates which represented 19 members of this family of organisms. The ranges of thermal death times at 60, 70, and 80 degrees C were 1.3 to 10.6, 0.7 to 2.6, and 0.3 to 0.7 min, respectively. These data suggest that the method of heat eradication will be effective against all members of the family Legionellaceae.

Hot Temperature↗
PubMed1985

Isolation of Legionella pneumophila from the cold water of hospital ice machines: implications for origin and transmission of the organism.

Although the mode of transmission of L. pneumophila is as yet unclear, the hot water distribution system has been shown to be the reservoir for Legionella within the hospital environment. In this report we identify a previously unrecognized reservoir for L. pneumophila within the hospital environment, ie, the cold water dispensers of hospital ice machines. The cold water dispensers of 14 ice machines were cultured monthly over a 1-year period. Positive cultures were obtained from 8 of 14 dispensers, yielding from 1 to 300 CFU/plate. We were able to link the positivity of these cold water sites to the incoming cold water supply by recovering L. pneumophila from the cold water storage tank, which is directly supplied by the incoming municipal water line. This was accomplished by a novel enrichment experiment designed to duplicate the conditions (temperature, sediment, stagnation, and continuous seeding) of the hot water system. Our data indicate that significant contamination of cold water outlets with L. pneumophila can occur. Although no epidemiologic link to disease was made, the fact that the primary source of a patient's drinking water is from the ice machines warrants further investigation of these water sources as possible reservoirs.

Bacteriological Techniques↗
PubMed1985

Ecology of Legionella pneumophila within water distribution systems.

The reservoir for hospital-acquired Legionnaires disease has been shown to be the potable water distribution system. We investigated the influence of the natural microbial population and sediment (scale and organic particulates) found in water systems as growth-promoting factors for Legionella pneumophila. Our in vitro experiments showed that: (i) water from hot-water storage tank readily supported the survival of L. pneumophila, (ii) the concentration of sediment was directly related to the survival of L. pneumophila, (iii) the presence of environmental bacteria improved the survival of L. pneumophila via nutritional symbiosis, (iv) the combination of sediment and environmental bacteria acted synergistically to improve the survival of L. pneumophila, and (v) the role of sediment in this synergistic effect was determined to be nutritional. Sediment was found to stimulate the growth of environmental microflora, which in turn stimulated the growth of L. pneumophila. These findings confirm the empiric observations of the predilection of L. pneumophila for growth in hot-water tanks and its localization to sediment. L. pneumophila occupies an ecological niche within the potable water system, with interrelationships between microflora, sediment, and temperature.

Bacteria↗
PubMed1985

Tatlockia micdadei (Pittsburgh pneumonia agent) growth kinetics may explain its infrequent isolation from water and the low prevalence of Pittsburgh pneumonia.

Sediment and indigenous microflora taken from water distribution systems has been shown to promote the survival of Legionella pneumophila. The effect of sediment and indigenous microflora on Tatlockia micdadei (Pittsburgh pneumonia agent, PPA) was evaluated by growth curve experiments. Symbiosis between PPA and environmental bacteria was demonstrated by satellitism experiments. Unlike L. pneumophila, the concentration of PPA remained stationary in test tube suspensions containing both microflora and sediment. The difference in the ecology between the two organisms may explain the infrequent environmental recovery of PPA and, ultimately, the epidemiologic differences between Legionnaires disease and Pittsburgh pneumonia.

Bacteria↗
PubMedDate not supplied

Community-acquired pneumonia caused by Legionella dumoffii in a patient with hairy cell leukemia.

A case of community-acquired pneumonia caused by Legionella dumoffii in a patient with hairy cell leukemia is described. Diagnosis was confirmed by isolation by culture of sputum and broncho-alveolar lavage specimens, positive direct fluorescent antibody stains, and antibody seroconversion from 1:16 (acute) to 1:4096 (six months). The blue white autofluorescence of the L. dumoffii colonies when viewed under ultraviolet light was particularly useful in preliminary identification. The patient recovered from his pneumonia after administration of erythromycin and rifampin. Legionella have been shown to multiply in monocytes and cell-mediated immunity appears to be the primary mechanism of host defense in man. Hairy cell leukemia is characterized by monocyte dysfunction and such patients have a predilection for infection by microbes that are controlled by cell-mediated defenses. We review other cases of community-acquired L. dumoffii pneumonia as well as other cases of Legionella infection in patients with hairy cell leukemia.

Antibodies, Bacterial↗
PubMedDate not supplied

Factors predisposing to Legionella pneumophila colonization in residential water systems.

Fifty-five homes in the Pittsburgh area were surveyed for the presence of Legionella pneumophila colonization. Hot water tanks, faucets, and showerheads were sampled. Six homes yielded Legionella pneumophila within the water distribution system. Lower water temperatures (less than 48.8 degrees C) within the hot water system were significantly associated with the presence of L. pneumophila colonization. A similar association was found for electric heaters; however, this association may be an indirect one. Water temperatures in electrically heated tanks were significantly lower than in gas-heated tanks. City residences were also more likely to be colonized than suburban residences. Because acquisition of Legionnaires' disease in the community has been linked to colonization of the water supplies in the homes of affected patients, these findings may have clinical implications for susceptible individuals residing in homes with water supplies colonized by L. pneumophila.

Hot Temperature↗