Pneumophila Bacteria Research Articles

Detection of Legionella pneumophila bacteria from water sources in Palembang City, Indonesia

Detection of Legionella pneumophila bacteria from water sources in Palembang City, Indonesia

Antibiotic sensitivity of environmental Legionella pneumophila strains isolated in Poland.

Legionella bacteria are commonly found in natural aquatic environments such as rivers, lakes, ponds and hot springs. Legionella infection occurs through the inhalation of water-air aerosol generated, for example, by showers or hot tubs. The most common species responsible for infection is Legionella pneumophila, which can cause Pontiac fever, and Legionnaires' disease, as well as a rare extrapulmonary form. The aim of the study's is to assess the susceptibility of Legionella pneumophila bacteria isolated from water systems of public buildings in Poland to antibiotics and chemotherapeutic agents used in the treatment of Legionellosis pneumonia. A total of 100 L. pneumophila strains isolated from public buildings, such as hospitals and water recreation facilities, were used for the study. The drug sensitivity of the following antibiotics was determined: erythromycin, azithromycin, ciprofloxacin, levofloxacin, rifampicin, trimethoprim-sulfamethoxazole and tetracycline. Mean MIC50 and MIC90 values were read using accepted standards. The highest mean MIC value was obtained for tetracycline 6,130+/-0,353 μg/ml (with a range from 1,500 μg/ml to 16,000 μg/ml. In contrast, the lowest MIC was recorded with rifampicin: 0.020+/-0.037 μg/ml (with a range from 0.016 μg/ml to 0.380 μg/ml). The lowest biocidal concentration was found for levofloxacin, the highest for tetracycline. The highest MIC50 and MIC90 values were found for tetracycline and the lowest for rifampicin. The highest biocidal values were found for azithromycin and the lowest for tetracycline.

Investigation of Legionella Pneumophila bacteria in hospital water supply systems

Investigation of Legionella Pneumophila bacteria in hospital water supply systems

CHC22 clathrin mediates traffic from early secretory compartments for human GLUT4 pathway biogenesis.

Glucose transporter 4 (GLUT4) is sequestered inside muscle and fat and then released by vesicle traffic to the cell surface in response to postprandial insulin for blood glucose clearance. Here, we map the biogenesis of this GLUT4 traffic pathway in humans, which involves clathrin isoform CHC22. We observe that GLUT4 transits through the early secretory pathway more slowly than the constitutively secreted GLUT1 transporter and localize CHC22 to the ER-to-Golgi intermediate compartment (ERGIC). CHC22 functions in transport from the ERGIC, as demonstrated by an essential role in forming the replication vacuole of Legionella pneumophila bacteria, which requires ERGIC-derived membrane. CHC22 complexes with ERGIC tether p115, GLUT4, and sortilin, and downregulation of either p115 or CHC22, but not GM130 or sortilin, abrogates insulin-responsive GLUT4 release. This indicates that CHC22 traffic initiates human GLUT4 sequestration from the ERGIC and defines a role for CHC22 in addition to retrograde sorting of GLUT4 after endocytic recapture, enhancing pathways for GLUT4 sequestration in humans relative to mice, which lack CHC22.

New Solar Water Heating System: Safety, Design and Implementation Issues

Abstract This paper presents a new electronic controller, devoted to solar water heating systems, that implements safety functions to prevent L. pneumophila bacteria outbreaks. The controller uses data retrieved from strategically located probes in order to implement the proposed safety actions. The electronic solution was integrated and validated on a solar system prototype bench that uses real equipment such as collectors, a water storage tank and expansion vessels. Moreover, two particular solar water heating installations were designed devoted to a house family and a nursing home both located on the Mealhada area. The methodology and reported technical solutions in this research could be a practical guide to promote mass market usage of the solar water heating systems in Portugal.

The unprecedented 2014 Legionnaires' disease outbreak in Portugal: atmospheric driving mechanisms.

A large outbreak of Legionnaires' disease occurred in November 2014 nearby Lisbon, Portugal. This epidemic infected 377 individuals by the Legionella pneumophila bacteria, resulting in 14 deaths. The primary source of transmission was contaminated aerosolized water which, when inhaled, lead to atypical pneumonia. The unseasonably warm temperatures during October 2014 may have played a role in the proliferation of Legionella species in cooling tower systems. The episode was further exacerbated by high relative humidity and a thermal inversion which limited the bacterial dispersion. Here, we analyze if the Legionella outbreak event occurred during a situation of extreme potential recirculation and/or stagnation characteristics. In order to achieve this goal, the Allwine and Whiteman approach was applied for a hindcast simulation covering the affected area during a near 20-year long period (1989-2007) and then for an independent period covering the 2014 event (15 October to 13 November 2014). The results regarding the average daily critical transport indices for the 1989-2007 period clearly indicate that the airshed is prone to stagnation as these events have a dominant presence through most of the study period (42%), relatively to the occurrence of recirculation (18%) and ventilation (17%) events. However, the year of 2014 represents an exceptional year when compared to the 1989-2007 period, with 53 and 33% of the days being classified as under stagnation and recirculation conditions, respectively.

The 2015 New York City Legionnaires' Disease Outbreak: A Case Study on a History-Making Outbreak.

The 2015 New York City Legionnaires' Disease Outbreak: A Case Study on a History-Making Outbreak.

Subversion of Cell-Autonomous Immunity and Cell Migration by Legionella pneumophila Effectors.

Bacteria trigger host defense and inflammatory processes, such as cytokine production, pyroptosis, and the chemotactic migration of immune cells toward the source of infection. However, a number of pathogens interfere with these immune functions by producing specific so-called “effector” proteins, which are delivered to host cells via dedicated secretion systems. Air-borne Legionella pneumophila bacteria trigger an acute and potential fatal inflammation in the lung termed Legionnaires’ disease. The opportunistic pathogen L. pneumophila is a natural parasite of free-living amoebae, but also replicates in alveolar macrophages and accidentally infects humans. The bacteria employ the intracellular multiplication/defective for organelle trafficking (Icm/Dot) type IV secretion system and as many as 300 different effector proteins to govern host–cell interactions and establish in phagocytes an intracellular replication niche, the Legionella-containing vacuole. Some Icm/Dot-translocated effector proteins target cell-autonomous immunity or cell migration, i.e., they interfere with (i) endocytic, secretory, or retrograde vesicle trafficking pathways, (ii) organelle or cell motility, (iii) the inflammasome and programed cell death, or (iv) the transcription factor NF-κB. Here, we review recent mechanistic insights into the subversion of cellular immune functions by L. pneumophila.

Survival of Biofilm‐Associated Legionella pneumophila Exposed to Various Stressors

Biofilm is crucial for the multiplication and survival of Legionella pneumophila. The survival after different stressors of biofilm-associated L. pneumophila was evaluated during 150 days in this study. Mixed biofilms were allowed to develop on coupons in a biofilm reactor, which was experimentally infected with L. pneumophila. A dose of 2 ppm of monochloramine was found ineffective to kill younger (60 days) biofilm-associated L. pneumophila, whereas shock treatment (500 and 1000 ppm) was found to be significantly successful, as expected. Also, short exposure to 60 °C was insufficient to kill all young L. pneumophila within biofilms. A significant amount of young L. pneumophila bacteria also resisted pH 11 and 3 molar salt solution. No significant change was observed after exposure to 4 °C, ultra pure water and pH 5. Interestingly, L. pneumophila bacteria in biofilm became more sensitive after 90 days.

Can rapid pressure decrease induced by supercavitation efficiently eradicate Legionella pneumophila bacteria?

The presence of Legionella pneumophila bacteria in engineered water systems can pose a significant health risk. Current prevention and outbreak treatments are cost and environmentally ineffective. Moreover they do not prevent rapid bacteria recolonization. Although cavitation was already suggested as a possible water treatment technique a systematic study has not yet been performed. In the present experimental campaign we set out to evaluate the efficiency of removal of L. pneumophila by three types of cavitation—the most commonly used acoustic cavitation, the aggressive developed hydrodynamic cavitation, and the supercavitation. We show that it is probably not the pressure peaks or the high local temperatures that cause the eradication of the bacteria, but the rapid pressure decrease which was initiated in supercavitating flow regime. Results of the study show promising ground for further optimization of a methodology for L. pneumophila removal by cavitation.

Electrochemical Inactivation of P. Aeruginosa, A. hydrophila, L. pneumophila using Boron Doped Diamond Anodes

AbstractPseudomonas Aeruginosa, Aeromonas hydrophila, Legionella pneumophila bacteria are waterborne pathogens commonly found in water and linked to infectious diseases. Especially, they can survive and colonize water systems, particularly in worm water system. On-site supplemental disinfection of water systems might be one of the approaches to prevent water born diseases. In this work, the inactivation of these waterborne pathogens using a single compartment electrochemical flow cell equipped with Boron Doped Diamond (BDD) anode and Titanium cathode was investigated. The bactericidal activity of galvanostatic electrolysis using BDD anode was evaluated on synthetic contaminated waters containing P. Aeruginosa, A. hydrophila, L. pneumophila. BDDanodic oxidation at current density of 50 mA cm

Distribution of Legionella pneumophila bacteria and Naegleria and Hartmannella amoebae in thermal saline baths used in balneotherapy

The present study was aimed at investigating the coexistence and interactions between free living amoebae of Naegleria and Hartmannella genera and pathogenic Legionella pneumophila bacteria in thermal saline baths used in balneotherapy in central Poland. Water samples were collected from November 2010 to May 2011 at intervals longer than 1 month. The microorganisms were detected with the use of a very sensitive fluorescence in situ hybridisation method. In addition, the morphology of the amoebae was studied. Despite relatively high salinity level, ranging from 1.5 to 5.0 %, L. pneumophila were found in all investigated baths, although their number never exceeded 106 cells dm−3. Hartmannella were not detected, while Naegleria fowleri were found in one bath. The observation that N. fowleri and L. pneumophila may coexist in thermal saline baths is the first observation emphasising potential threat from these microorganisms in balneotherapy.

Legionnaires' disease: pathology, detection and management

Legionnaires' disease is a potentially fatal form of pneumonia, which is caused by the bacterium Legionella pneumophila and related bacteria that can be found naturally in environmental water sources. In the UK, all dental premises are required to have a written scheme and a Legionella risk assessment. Barry Quinn and Richard Johnson explain

UV-A photocatalytic treatment of Legionella pneumophila bacteria contaminated airflows through three-dimensional solid foam structured photocatalytic reactors

A 3D-structured photocatalytic media was designed for allowing a tubular reactor to work in a traversing-flow mode at low pressure drops with a strong increase in the surface area-to-volume ratio inside the reactor. A protective polysiloxane coating was performed for protecting a structured polyurethane foam and anchoring the active TiO 2 particles. Filled with the 3D-structured solid foam supporting TiO 2 photocatalyst, the reactor could thus take advantages from the static mixer effect and from the low pressure drop resulting from the reticulated foam support. Very efficient decontamination levels towards airborne Legionella pneumophila bacteria were reached in a single-pass test mode.

The use of copper and silver in carbon point-of-use filters for the suppression of Legionella throughput in domestic water systems

To evaluate throughput of seeded Legionella pneumophila bacteria in domestic point-of-use filters. The filters were challenged with tap water seeded with Leg. pneumophila. After multiple challenge events (4.25 x 10(11) CFU per filter), the levels of Legionella were lower in the effluent from the filter containing both copper and silver (mean 4.48 x 10(3) CFU ml(-1)) than in the effluent from the filter containing copper only (1.26 x 10(4) CFU ml(-1); P < 0.001). After a single challenge event of approx. 5 x 10(9) CFU L. pneumophila per filter, there was no significant difference between the levels of Legionella in the effluents from a carbon filter containing copper and a carbon filter with no metals (mean 6.87 x 10(2) and 6.89 x 10(2) CFU ml(-1), respectively; P = 0.985). Legionella was detected in filter effluent up to 6 weeks after being challenged, indicating that while filters may reduce the levels during an initial contamination event, the exposure is extended as the accumulated bacteria slough off over time. This study has provided an understanding of the response of Legionella to the use of silver and copper in domestic point-of-use carbon filters.

UV-A photocatalytic treatment of high flow rate air contaminated with Legionella pneumophila

A new photoreactor geometry has been designed to treat high flow rate air contaminated with airborne Legionella pneumophila bacteria by exclusive UV-A photocatalysis. A specific tangential reactor geometry with periodical illumination allowed high efficiencies for strongly contaminated air streams to be obtained, whereas its self-driven property strongly decreased the charge loss phenomena, crucial for targeting high flow rate air treatment applications. This type of photoreactor has been used as the basis for designing and commercializing photocatalytic decontamination devices for applications in the field of air treatment technology.

Legionella pneumophila in an ammonia plant cooling tower

AbstractIn 1999, 30 people died from infection by Legionella pneumophila bacteria after visiting a flower exhibition in Bovenkarspel, The Netherlands. This event prompted Kemira Agro Rozenburg to sample its cooling tower water at regular intervals for the presence of the Legionella bacteria.The results were consistently negative until the spring of 2000 when a sudden outbreak of the bacteria was detected. Safety measures were implemented immediately, the cause of the outbreak was discovered, and measures were subsequently taken to prevent a reoccurrence.

Humoral immunity and regulation of intrapulmonary growth of Legionella pneumophila in the immunocompetent host.

The potential role of humoral immunity in regulating intrapulmonary growth of Legionella pneumophila in the immunocompetent host was investigated using a murine model of Legionnaires' disease. Intratracheal inoculation of A/J mice with a virulent strain of L. pneumophila (10(6) bacteria per mouse) resulted in the recruitment of B lymphocytes into the lung and the development of anti-L. pneumophila Ab. Opsonization of L. pneumophila in vitro with anti-L. pneumophila-specific mAb resulted in a significant decrease in intrapulmonary growth of the bacteria at 24 to 72 h postinfection. Transmission electron microscopic analysis of lung tissue from L. pneumophila- infected mice demonstrated that while there was no significant difference between phagocytosis of the unopsonized and opsonized L. pneumophila by alveolar macrophages at 24 h postinfection, phagocytosis of opsonized bacteria by alveolar mononuclear phagocytic cells was significantly enhanced at 48 h postinfection. Depletion of A/J mice of complement before intratracheal inoculation of opsonized L. pneumophila (10(6) bacteria per mouse) did not significantly alter intrapulmonary growth of L. pneumophila. These results suggest that anti-L. pneumophila Ab, produced during replicative L. pneumophila lung infections, may regulate intrapulmonary growth of L. pneumophila in the immunocompetent host by decreasing the viability of extracellular L. pneumophila and by enhancing phagocytosis of the bacteria by alveolar mononuclear phagocytic cells by a complement-independent mechanism.

Effector mechanisms responsible for gamma interferon-mediated host resistance to Legionella pneumophila lung infection: the role of endogenous nitric oxide differs in susceptible and resistant murine hosts.

To facilitate identification of the effector mechanism(s) responsible for gamma interferon (IFN-gamma)-mediated host resistance to Legionella pneumophila, a murine model of legionellosis in BALB/c mice with a targeted disruption in the IFN-gamma gene (gamma knockout [GKO] mice) was developed. Immunocompetent BALB/c mice and GKO mice were inoculated intratracheally with virulent L. pneumophila (10(6) bacteria per mouse), and bacterial clearance and the pulmonary inflammatory response were assessed. L. pneumophila did not replicate in, and was rapidly cleared from, the lungs of immunocompetent BALB/c mice, demonstrating that immunocompetent BALB/c mice are resistant to replicative L. pneumophila pulmonary infections. In contrast, similarly infected GKO mice developed persistent, replicative intrapulmonary L. pneumophila infections with extrapulmonary dissemination of the bacteria to the spleen. Histopathologic and flow cytometric analysis of L. pneumophila-infected lung tissue demonstrated that while immunocompetent BALB/c mice develop multifocal pneumonitis which resolves, similarly infected GKO mice develop diffuse pneumonitis with persistent neutrophil recruitment into the lung. Intratracheal administration of exogenous IFN-gamma to L. pneumophila-infected GKO mice facilitated intrapulmonary clearance of the bacteria, confirming the pivotal role of IFN-gamma in innate host defenses to L. pneumophila lung infection in this murine host. The potential role of endogenous reactive nitrogen intermediates, including nitric oxide (NO), in IFN-gamma-mediated resistance to L. pneumophila pulmonary infections in immunocompetent BALB/c mice was subsequently assessed. Macrophage inducible nitric oxide synthetase (an enzyme responsible for the production of NO) was induced in alveolar cells from L. pneumophila-infected immunocompetent BALB/c mice (with maximal expression at 48 h postinfection) but was not induced in similarly infected GKO mice. However, administration of the NO synthetase inhibitor N-monomethyl-L-arginine did not significantly inhibit clearance of L. pneumophila from the lung of immunocompetent BALB/c mice (compared with that in similarly infected mice not administered N-monomethyl-L-arginine). In contrast, we have previously demonstrated that IFN-gamma-induced host resistance to replicative L. pneumophila lung infections in a susceptible murine host (A/J mice) is mediated, in part, by endogenous NO. Taken together, these studies identify a differing role of endogenous NO in IFN-gamma-mediated resistance to L. pneumophila pulmonary infection in susceptible and resistant murine hosts.

Detection of Legionella pneumophila in environmental water samples using a fluorescein conjugated monoclonal antibody.

Sixty-three environmental water samples from various sources were examined for the presence of Legionella pneumophila with a commercially available direct fluorescent monoclonal antibody (GS), an indirect fluorescent antibody test (IFAT) and culture. GS detected L. pneumophila in 94% and 100% of environmental water samples which were culture and IFAT positive for L. pneumophila, respectively. IFAT detected 69% of L. pneumophila culture positive samples. Cultures of L. pneumophila serogroups 1 to 12, 14 and non-L. pneumophila bacteria which may be found in water, and bacteria containing non-specific binding proteins, were stained by GS and IFAT. GS identified all serogroups of L. pneumophila and did not cross react with any non-L. pneumophila bacteria. L. pneumophila in environmental samples was easy to detect against a clear dark background when stained with GS.