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Barry S Fields - One of the best experts on this subject based on the ideXlab platform.
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introduction of monochloramine into a municipal water system impact on colonization of buildings by Legionella spp
Applied and Environmental Microbiology, 2006Co-Authors: Matthew R Moore, Barry S Fields, Marsha Pryor, Claressa E Lucas, Maureen Phelan, Richard E. BesserAbstract:Legionnaires' disease (LD) outbreaks are often traced to colonized potable water systems. We collected water samples from potable water systems of 96 buildings in Pinellas County, Florida, between January and April 2002, during a time when chlorine was the primary residual disinfectant, and from the same buildings between June and September 2002, immediately after monochloramine was introduced into the municipal water system. Samples were cultured for Legionellae and amoebae using standard methods. We determined predictors of Legionella colonization of individual buildings and of individual sampling sites. During the chlorine phase, 19 (19.8%) buildings were colonized with Legionellae in at least one sampling site. During the monochloramine phase, six (6.2%) buildings were colonized. In the chlorine phase, predictors of Legionella colonization included water source (source B compared to all others, adjusted odds ratio [aOR], 6.7; 95% confidence interval [CI], 2.0 to 23) and the presence of a system with continuously circulating hot water (aOR, 9.8; 95% CI, 1.9 to 51). In the monochloramine phase, there were no predictors of individual building colonization, although we observed a trend toward greater effectiveness of monochloramine in hotels and single-family homes than in county government buildings. The presence of amoebae predicted Legionella colonization at individual sampling sites in both phases (OR ranged from 15 to 46, depending on the phase and sampling site). The routine introduction of monochloramine into a municipal drinking water system appears to have reduced colonization by Legionella spp. in buildings served by the system. Monochloramine may hold promise as community-wide intervention for the prevention of LD.
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Gamma-Proteobacteria Aquicella lusitana gen. nov., sp. nov., and Aquicella siphonis sp. nov. Infect Protozoa and Require Activated Charcoal for Growth in Laboratory Media
Applied and environmental microbiology, 2003Co-Authors: Paula Santos, Barry S Fields, Robert F. Benson, Isabel Pinhal, Fred A. Rainey, Nuno Empadinhas, Joana Costa, António Veríssimo, Milton S. Da CostaAbstract:Several isolates, belonging to two new species of the same novel genus of gamma-proteobacteria, were recovered from drilled well (borehole) and spa water at Sao Gemil in central Portugal. These organisms are phylogenetically most closely related to the strictly intracellular uncultured species of the genus Rickettsiella, which cause disease in arthropods, and to the facultatively intracellular species of the genus Legionella, some of which cause Legionnaires' disease and Pontiac fever. The Sao Gemil strains grew only on media containing charcoal, as is also true of the species of the genus Legionella. Unlike the vast majority of Legionella isolates, the new isolates did not require l-cysteine or ferric pyrophosphate for growth but like the Legionellae had an absolute requirement for α-ketoglutarate. Strains SGT-39T and SGT-56 grew consistently between 30 and 43°C, while strains SGT-108T and SGT-109 grew between 30 and 40°C. The pH ranges for growth of these organisms were surprisingly narrow: strains SGT-39T and SGT-56 grew between pH 6.3 and 7.3, while strains SGT-108T and SGT-109 grew between pH 6.3 and 7.0. Both organisms proliferated in the amoeba Hartmannella vermiformis but did not grow in U937 human cells. Based on 16S rRNA gene sequence analysis and physiological, biochemical, and chemical analysis we describe two new species of one novel genus; one species is represented by strain SGT-39T, for which we propose the name Aquicella lusitana, while strain SGT-108T represents a second species of the same genus, for which we propose the name Aquicella siphonis.
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role of biofilms in the survival of Legionella pneumophila in a model potable water system
Microbiology, 2001Co-Authors: Ricardo Murga, Barry S Fields, Ellen Brown, Terri S Forster, Janet M Pruckler, Rodney M DonlanAbstract:Legionellae can infect and multiply intracellularly in both human phagocytic cells and protozoa. Growth of Legionellae in the absence of protozoa has been documented only on complex laboratory media. The hypothesis upon which this study was based was that biofilm matrices, known to provide a habitat and a gradient of nutrients, might allow the survival and multiplication of Legionellae outside a host cell. This study determined whether Legionella pneumophila can colonize and grow in biofilms with and without an association with Hartmannella vermiformis. The laboratory model used a rotating disc reactor at a retention time of 6·7 h to grow biofilms on stainless steel coupons. The biofilm was composed of Pseudomonas aeruginosa, Klebsiella pneumoniae and a Flavobacterium sp. The levels of L. pneumophila cells present in the biofilm were monitored for 15 d, with and without the presence of H. vermiformis, and it was found that, although unable to replicate in the absence of H. vermiformis, L. pneumophila was able to persist.
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Pontiac Fever Due to Legionella micdadei from a Whirlpool Spa: Possible Role of Bacterial Endotoxin
The Journal of infectious diseases, 2001Co-Authors: Barry S Fields, Thomas E. Haupt, Jeffrey P. Davis, Matthew J. Arduino, Phyllis H. Miller, Jay C. ButlerAbstract:During January 1998, a cluster of illnesses occurred among hotel guests in Wisconsin. Ill persons had been exposed to the hotel's whirlpool spa and swimming pool. Symptoms included headache, fever, chills, myalgia, shortness of breath, and fatigue. A diagnosis of Pontiac fever was made, based on serologic evidence of acute infection with Legionella micdadei. High concentrations of heterotrophic bacteria were recovered from the spa, despite apparently high disinfectant levels. L. micdadei was isolated from the swimming pool filter and water from the spa after heat enrichment but not from pools and spas at nearby hotels. Water from hotel pools and spas was tested to determine endotoxin levels; water from the spa of the implicated hotel contained the highest concentration of endotoxin (14,40() endotoxin units/mL). Additional studies are needed to determine the role of endotoxin from Legionellae or other bacteria in the pathogenesis of Pontiac fever.
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outbreak of legionnaires disease among cruise ship passengers exposed to a contaminated whirlpool spa
The Lancet, 1996Co-Authors: D B Jernigan, Barry S Fields, Robert F. Benson, Robert F. Breiman, Jo Hofmann, Martin S Cetron, J P Nuorti, Harvey Lipman, R J Carter, C A GeneseAbstract:Abstract Summary Background Outbreaks of travel-related Legionnaires' disease present a public-health challenge since rapid, sensitive, and specific diagnostic tests are not widely used and because detection of clusters of disease among travellers is difficult. We report an outbreak of Legionnaires' disease among cruise ship passengers that occurred in April, 1994, but that went unrecognised until July, 1994. Methods After rapid diagnosis of Legionnaires' disease in three passengers by urine antigen testing, we searched for additional cases of either confirmed (laboratory evidence of infection) or probable Legionnaires' disease (pneumonia of undetermined cause). A case-control study was conducted to compare exposures and activities on the ship and in ports of call between each case-passenger and two or three matched control-passengers. Water samples from the ship, from sites on Bermuda, and from the ship's water source in New York City were cultured for Legionellae and examined with PCR. Findings 50 passengers with Legionnaires' disease (16 confirmed, 34 probable) were identified from nine cruises embarking between April 30 and July 9, 1994. Exposure to whirlpool spas was strongly associated with disease (odds ratio 16·2, 95% Cl 2·8-351·7); risk of acquiring Legionnaires' disease increased by 64% (95% Cl 12-140) for every hour spent in the spa water. Passengers spending time around the whirlpool spas, but not in the water, were also significantly more likely to have acquired infection. Legionella pneumophila serogroup 1 was isolated only from the sand filter in the ship's whirlpool spa. This isolate matched a clinical isolate from the respiratory secretions of a case-passenger as judged by monoclonal antibody subtyping and by arbitrarily primed PCR. Interpretation This investigation shows the benefit of obtaining a recent travel history, the usefulness or urine antigen testing for rapid diagnosis of Legionella infection, and the need for improved surveillance for travel-related Legionnaires' disease. New strategies for whirlpool spa maintenance and decontamination may help to minimise transmission of Legionellae from these aerosol-producing devices.
Julia Walochnik - One of the best experts on this subject based on the ideXlab platform.
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Free-living amoebae and their associated bacteria in Austrian cooling towers: a 1-year routine screening
Parasitology Research, 2016Co-Authors: Ute Scheikl, Han-fei Tsao, Alexander Indra, Matthias Horn, Julia WalochnikAbstract:Free-living amoebae (FLA) are widely spread in the environment and known to cause rare but often serious infections. Besides this, FLA may serve as vehicles for bacterial pathogens. In particular, Legionella pneumophila is known to replicate within FLA thereby also gaining enhanced infectivity. Cooling towers have been the source of outbreaks of Legionnaires’ disease in the past and are thus usually screened for Legionellae on a routine basis, not considering, however, FLA and their vehicle function. The aim of this study was to incorporate a screening system for host amoebae into a Legionella routine screening. A new real-time PCR-based screening system for various groups of FLA was established. Three cooling towers were screened every 2 weeks over the period of 1 year for FLA and Legionella spp., by culture and molecular methods in parallel. Altogether, 83.3 % of the cooling tower samples were positive for FLA, Acanthamoeba being the dominating genus. Interestingly, 69.7 % of the cooling tower samples were not suitable for the standard Legionella screening due to their high organic burden. In the remaining samples, positivity for Legionella spp. was 25 % by culture, but overall positivity was 50 % by molecular methods. Several amoebal isolates revealed intracellular bacteria.
Sophie Jarraud - One of the best experts on this subject based on the ideXlab platform.
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Diversity of Legionellae strains from Tunisian hot spring water.
Research in Microbiology, 2013Co-Authors: Taoufik Ghrairi, Nawel Chaftar, Sophie Jarraud, Jean Marc Berjeaud, Khaled Hani, Jacques FrereAbstract:The aim of this study was to evaluate the frequency of Legionella pneumophila in three hot spring water recreation areas by conventional culture on GVPC and by Real Time-PCR. No Legionellae were isolated from the spring water upstream the distribution system suggesting strongly that the thermal area was the probable source of these pathogens. L. pneumophila was present at high level in some samples, reaching values of 8.2 × 10(3) CFU/l at the site C. We observed a low diversity among the 18 isolated Legionella strains according to 16S DNA analysis, since only L. pneumophila and Legionella londiniensis were identified. All of the L. pneumophila strains belong to five serogroups (1, 4, 5, 6 and 8). Pulsed-field gel electrophoresis analysis identified various genotypes among these serogroups and showed that these strains had pulsotypes distinct from L. pneumophila present in the CNRL Legionella-database. These environmental strains showed higher tolerance to heat shock stress at 48 °C than L. pneumophila clinical strain, which may explain their presence in warm waters. Our data suggested that potential pathogen Legionellae are present in Tunisian medicalized thermal spas and emphasized the importance of adopting control measures to prevent infection.
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Quantitative real-time Legionella PCR for environmental water samples: data interpretation.
Applied and Environmental Microbiology, 2006Co-Authors: Philippe Joly, Pierre-alain Falconnet, Janine André, Nicole Weill, Monique Reyrolle, François Vandenesch, Max Maurin, Jerome Etienne, Sophie JarraudAbstract:Quantitative Legionella PCRs targeting the 16S rRNA gene (specific for the genus Legionella) and the mip gene (specific for the species Legionella pneumophila) were applied to a total of 223 hot water system samples (131 in one laboratory and 92 in another laboratory) and 37 cooling tower samples (all in the same laboratory). The PCR results were compared with those of conventional culture. 16S rRNA gene PCR results were nonquantifiable for 2.8% of cooling tower samples and up to 39.1% of hot water system samples, and this was highly predictive of Legionella CFU counts below 250/liter. PCR cutoff values for identifying hot water system samples containing >10(3) CFU/liter Legionellae were determined separately in each laboratory. The cutoffs differed widely between the laboratories and had sensitivities from 87.7 to 92.9% and specificities from 77.3 to 96.5%. The best specificity was obtained with mip PCR. PCR cutoffs could not be determined for cooling tower samples, as the results were highly variable and often high for culture-negative samples. Thus, quantitative Legionella PCR appears to be applicable to samples from hot water systems, but the positivity cutoff has to be determined in each laboratory.
Jay C. Butler - One of the best experts on this subject based on the ideXlab platform.
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Pontiac Fever Due to Legionella micdadei from a Whirlpool Spa: Possible Role of Bacterial Endotoxin
The Journal of infectious diseases, 2001Co-Authors: Barry S Fields, Thomas E. Haupt, Jeffrey P. Davis, Matthew J. Arduino, Phyllis H. Miller, Jay C. ButlerAbstract:During January 1998, a cluster of illnesses occurred among hotel guests in Wisconsin. Ill persons had been exposed to the hotel's whirlpool spa and swimming pool. Symptoms included headache, fever, chills, myalgia, shortness of breath, and fatigue. A diagnosis of Pontiac fever was made, based on serologic evidence of acute infection with Legionella micdadei. High concentrations of heterotrophic bacteria were recovered from the spa, despite apparently high disinfectant levels. L. micdadei was isolated from the swimming pool filter and water from the spa after heat enrichment but not from pools and spas at nearby hotels. Water from hotel pools and spas was tested to determine endotoxin levels; water from the spa of the implicated hotel contained the highest concentration of endotoxin (14,40() endotoxin units/mL). Additional studies are needed to determine the role of endotoxin from Legionellae or other bacteria in the pathogenesis of Pontiac fever.
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Use of Polymerase Chain Reaction in an Epidemiologic Investigation of Pontiac Fever
The Journal of infectious diseases, 1993Co-Authors: Lisa A. Miller, Robert F. Benson, James L. Beebe, Jay C. Butler, William J. Martin, Richard E. Hoffman, Barry S FieldsAbstract:In June 1992, 13 (38%) of 34 resort guests experienced illness that met a symptom-based case definition of Pontiac fever. Each ill guest reported using an indoor hot tub compared with 6 (29%) of 21 nonill guests (P < .001). Water samples from the indoor hot tub were culture-negative for Legionellae using standard techniques, coculture with amebae, and intraperitoneal inoculation of guinea pigs. However, polymerase chain reaction (PCR) testing of the water samples indicated the presence of Legionella pneumophila. Direct fluorescent antibody testing identified the organism as serogroup 6. Seroconversion to L. pneumophila serogroup 6 occurred in 7 (64%) of 11 ill guests and none of 5 nonill guests (P = .03). These results suggest that in certain circumstances, culture of environmental samples should be supplemented with additional tests such as PCR. These results are also consistent with the concept that Pontiac fever can be caused by nonviable Legionellae.
Robert F. Benson - One of the best experts on this subject based on the ideXlab platform.
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Gamma-Proteobacteria Aquicella lusitana gen. nov., sp. nov., and Aquicella siphonis sp. nov. Infect Protozoa and Require Activated Charcoal for Growth in Laboratory Media
Applied and environmental microbiology, 2003Co-Authors: Paula Santos, Barry S Fields, Robert F. Benson, Isabel Pinhal, Fred A. Rainey, Nuno Empadinhas, Joana Costa, António Veríssimo, Milton S. Da CostaAbstract:Several isolates, belonging to two new species of the same novel genus of gamma-proteobacteria, were recovered from drilled well (borehole) and spa water at Sao Gemil in central Portugal. These organisms are phylogenetically most closely related to the strictly intracellular uncultured species of the genus Rickettsiella, which cause disease in arthropods, and to the facultatively intracellular species of the genus Legionella, some of which cause Legionnaires' disease and Pontiac fever. The Sao Gemil strains grew only on media containing charcoal, as is also true of the species of the genus Legionella. Unlike the vast majority of Legionella isolates, the new isolates did not require l-cysteine or ferric pyrophosphate for growth but like the Legionellae had an absolute requirement for α-ketoglutarate. Strains SGT-39T and SGT-56 grew consistently between 30 and 43°C, while strains SGT-108T and SGT-109 grew between 30 and 40°C. The pH ranges for growth of these organisms were surprisingly narrow: strains SGT-39T and SGT-56 grew between pH 6.3 and 7.3, while strains SGT-108T and SGT-109 grew between pH 6.3 and 7.0. Both organisms proliferated in the amoeba Hartmannella vermiformis but did not grow in U937 human cells. Based on 16S rRNA gene sequence analysis and physiological, biochemical, and chemical analysis we describe two new species of one novel genus; one species is represented by strain SGT-39T, for which we propose the name Aquicella lusitana, while strain SGT-108T represents a second species of the same genus, for which we propose the name Aquicella siphonis.
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outbreak of legionnaires disease among cruise ship passengers exposed to a contaminated whirlpool spa
The Lancet, 1996Co-Authors: D B Jernigan, Barry S Fields, Robert F. Benson, Robert F. Breiman, Jo Hofmann, Martin S Cetron, J P Nuorti, Harvey Lipman, R J Carter, C A GeneseAbstract:Abstract Summary Background Outbreaks of travel-related Legionnaires' disease present a public-health challenge since rapid, sensitive, and specific diagnostic tests are not widely used and because detection of clusters of disease among travellers is difficult. We report an outbreak of Legionnaires' disease among cruise ship passengers that occurred in April, 1994, but that went unrecognised until July, 1994. Methods After rapid diagnosis of Legionnaires' disease in three passengers by urine antigen testing, we searched for additional cases of either confirmed (laboratory evidence of infection) or probable Legionnaires' disease (pneumonia of undetermined cause). A case-control study was conducted to compare exposures and activities on the ship and in ports of call between each case-passenger and two or three matched control-passengers. Water samples from the ship, from sites on Bermuda, and from the ship's water source in New York City were cultured for Legionellae and examined with PCR. Findings 50 passengers with Legionnaires' disease (16 confirmed, 34 probable) were identified from nine cruises embarking between April 30 and July 9, 1994. Exposure to whirlpool spas was strongly associated with disease (odds ratio 16·2, 95% Cl 2·8-351·7); risk of acquiring Legionnaires' disease increased by 64% (95% Cl 12-140) for every hour spent in the spa water. Passengers spending time around the whirlpool spas, but not in the water, were also significantly more likely to have acquired infection. Legionella pneumophila serogroup 1 was isolated only from the sand filter in the ship's whirlpool spa. This isolate matched a clinical isolate from the respiratory secretions of a case-passenger as judged by monoclonal antibody subtyping and by arbitrarily primed PCR. Interpretation This investigation shows the benefit of obtaining a recent travel history, the usefulness or urine antigen testing for rapid diagnosis of Legionella infection, and the need for improved surveillance for travel-related Legionnaires' disease. New strategies for whirlpool spa maintenance and decontamination may help to minimise transmission of Legionellae from these aerosol-producing devices.
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Use of Polymerase Chain Reaction in an Epidemiologic Investigation of Pontiac Fever
The Journal of infectious diseases, 1993Co-Authors: Lisa A. Miller, Robert F. Benson, James L. Beebe, Jay C. Butler, William J. Martin, Richard E. Hoffman, Barry S FieldsAbstract:In June 1992, 13 (38%) of 34 resort guests experienced illness that met a symptom-based case definition of Pontiac fever. Each ill guest reported using an indoor hot tub compared with 6 (29%) of 21 nonill guests (P < .001). Water samples from the indoor hot tub were culture-negative for Legionellae using standard techniques, coculture with amebae, and intraperitoneal inoculation of guinea pigs. However, polymerase chain reaction (PCR) testing of the water samples indicated the presence of Legionella pneumophila. Direct fluorescent antibody testing identified the organism as serogroup 6. Seroconversion to L. pneumophila serogroup 6 occurred in 7 (64%) of 11 ill guests and none of 5 nonill guests (P = .03). These results suggest that in certain circumstances, culture of environmental samples should be supplemented with additional tests such as PCR. These results are also consistent with the concept that Pontiac fever can be caused by nonviable Legionellae.