scholarly journals Humidifier-associated paediatric Legionnaires' disease, Israel, February 2012

2012 ◽  
Vol 17 (41) ◽  
Author(s):  
J Moran-Gilad ◽  
T Lazarovitch ◽  
M Mentasti ◽  
T Harrison ◽  
M Weinberger ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Cold Water ◽  
Tap Water ◽  
Fatal Case ◽  
Control Measures ◽  
Free Standing ◽  
Legionnaires Disease

We report a fatal case of community-acquired Legionnaires' disease in an infant aged under six months. Epidemiological and microbiological investigations suggested that a free-standing cold water humidifier using domestic tap water contaminated with Legionella pneumophila serogroup 1 served as a vehicle for infection. These findings were corroborated by sequence-based typing (SBT). Humidifier-associated Legionnaires' disease can be prevented by appropriate control measures. This case also illustrates the emerging role of SBT in the investigation of legionellosis.

scholarly journals Legionella pneumophila CRISPR-Cas suggests recurrent encounters with one or more phages in the family Microviridae .

2021 ◽  
Author(s):  
Shayna R. Deecker ◽  
Malene L. Urbanus ◽  
Beth Nicholson ◽  
Alexander W. Ensminger
Keyword(s):  
Legionella Pneumophila ◽  
Sequence Similarity ◽  
Mobile Element ◽  
Current Data ◽  
Significant Sequence Similarity ◽  
Remediation Strategies ◽  
The Family ◽  
Legionnaires Disease ◽  
Outstanding Question

Legionella pneumophila is a ubiquitous freshwater pathogen and the causative agent of Legionnaires’ disease. L. pneumophila growth within protists provides a refuge from desiccation, disinfection, and other remediation strategies. One outstanding question has been whether this protection extends to phages. L. pneumophila isolates are remarkably devoid of prophages and to date no Legionella phages have been identified. Nevertheless, many L. pneumophila isolates maintain active CRISPR-Cas defenses. So far, the only known target of these systems is an episomal element that we previously named Legionella Mobile Element-1 (LME-1). The continued expansion of publicly available genomic data promises to further our understanding of the role of these systems. We now describe over 150 CRISPR-Cas systems across 600 isolates to establish the clearest picture yet of L. pneumophila ’s adaptive defenses. By searching for targets of 1,500 unique CRISPR-Cas spacers, LME-1 remains the only identified CRISPR-Cas targeted integrative element. We identified 3 additional LME-1 variants - all targeted by previously and newly identified CRISPR-Cas spacers - but no other similar elements. Notably, we also identified several spacers with significant sequence similarity to microviruses, specifically those within the subfamily Gokushovirinae . These spacers are found across several different CRISPR-Cas arrays isolated from geographically diverse isolates, indicating recurrent encounters with these phages. Our analysis of the extended Legionella CRISPR-Cas spacer catalog leads to two main conclusions: current data argue against CRISPR-Cas targeted integrative elements beyond LME-1, and the heretofore unknown L. pneumophila phages are most likely lytic gokushoviruses. IMPORTANCE Legionnaires’ disease is an often-fatal pneumonia caused by Legionella pneumophila , which normally grows inside amoebae and other freshwater protists. L. pneumophila trades diminished access to nutrients for the protection and isolation provided by the host. One outstanding question is whether L. pneumophila is susceptible to phages, given the protection provided by its intracellular lifestyle. In this work, we use Legionella CRISPR spacer sequences as a record of phage infection to predict that the “missing” L. pneumophila phages belong to the microvirus subfamily Gokushovirinae . Gokushoviruses are known to infect another intracellular pathogen, Chlamydia . How do gokushoviruses access L. pneumophila (and Chlamydia ) inside their “cozy niches”? Does exposure to phages happen during a transient extracellular period (during cell-to-cell spread) or is it indicative of a more complicated environmental lifestyle? One thing is clear, 100 years after their discovery, phages continue to hold important secrets about the bacteria upon which they prey.

scholarly journals Evaluation of Microbiological and Free-Living Protozoa Contamination in Dental Unit Waterlines

2019 ◽  
Vol 16 (15) ◽  
pp. 2648 ◽  
Author(s):  
Anna Maria Spagnolo ◽  
Marina Sartini ◽  
David Di Cave ◽  
Beatrice Casini ◽  
Benedetta Tuvo ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Tap Water ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Dental Staff ◽  
Plate Counts ◽  
Dental Unit Waterlines ◽  
Heterotrophic Plate Counts

Studies conducted over the last 40 years have demonstrated that the water output from dental unit waterlines (DUWLs) is often contaminated with high densities of microorganisms. It has been monitored the microbiological quality of the water in 30 public dental facilities in northern Italy in order to assess the health risk for patients and dental staff. In each facility, samples of water both from taps and from DUWLs were analyzed in order to evaluate heterotrophic plate counts (HPCs) at 22 °C and 36 °C, and to detect coliform bacteria, Pseudomonas aeruginosa, Legionella pneumophila and amoebae. In 100% of the samples taken from the DUWLs, the concentration of HPCs was above the threshold as determined by the Ministère de la Santé et des Solidarités (2007). The concentration of P. aeruginosa was greater than the indicated threshold in 16.67% of the hand-pieces analyzed. A total of 78.33% of samples were contaminated by L. pneumophila, while in the samples taken from the DUWLs alone, this percentage rose to 86.67%. Amoebae were detected in 60% of the samples taken from hand-pieces; all belonging to the species V. vermiformis. This study documented the presence of various microorganisms, including Legionella spp., at considerably higher concentrations in water samples from DUWLs than in samples of tap water in the same facilities, confirming the role of the internal DUWLs in increasing microbial contamination, especially in the absence of proper management of waterborne health risks.

scholarly journals Flagellum of Legionella pneumophilaPositively Affects the Early Phase of Infection of Eukaryotic Host Cells

2001 ◽  
Vol 69 (4) ◽  
pp. 2116-2122 ◽  
Author(s):  
Claudia Dietrich ◽  
Klaus Heuner ◽  
Bettina C. Brand ◽  
Jörg Hacker ◽  
Michael Steinert
Keyword(s):  
Electron Microscopy ◽  
Legionella Pneumophila ◽  
Kanamycin Resistance ◽  
Etiologic Agent ◽  
Polyclonal Antiserum ◽  
Host Cells ◽  
Kanamycin Resistance Cassette ◽  
Legionnaires Disease ◽  
Invasion Capacity

ABSTRACT Legionella pneumophila, the etiologic agent of Legionnaires' disease, contains a single, monopolar flagellum which is composed of one major subunit, the FlaA protein. To evaluate the role of the flagellum in the pathogenesis and ecology ofLegionella, the flaA gene of L. pneumophila Corby was mutagenized by introduction of a kanamycin resistance cassette. Immunoblots with antiflagellin-specific polyclonal antiserum, electron microscopy, and motility assays confirmed that the specific flagellar mutant L. pneumophila Corby KH3 was nonflagellated. The redelivery of the intact flaA gene into the chromosome (L. pneumophila Corby CD10) completely restored flagellation and motility. Coculture studies showed that the invasion efficiency of the flaA mutant was moderately reduced in amoebae and severely reduced in HL-60 cells. In contrast, adhesion and the intracellular rate of replication remained unaffected. Taking these results together, we have demonstrated that the flagellum of L. pneumophila positively affects the establishment of infection by facilitating the encounter of the host cell as well as by enhancing the invasion capacity.

scholarly journals Legionella pneumophila Entry GenertxA Is Involved in Virulence

2001 ◽  
Vol 69 (1) ◽  
pp. 508-517 ◽  
Author(s):  
Suat L. G. Cirillo ◽  
Luiz E. Bermudez ◽  
Sahar H. El-Etr ◽  
Gerald E. Duhamel ◽  
Jeffrey D. Cirillo
Keyword(s):  
Legionella Pneumophila ◽  
Bacterial Species ◽  
Host Cells ◽  
Intracellular Pathogen ◽  
Wild Type ◽  
Integrin Receptors ◽  
Legionnaires Disease ◽  
Cell Spread ◽  
Gain Access

ABSTRACT Successful parasitism of host cells by intracellular pathogens involves adherence, entry, survival, intracellular replication, and cell-to-cell spread. Our laboratory has been examining the role of early events, adherence and entry, in the pathogenesis of the facultative intracellular pathogen Legionella pneumophila. Currently, the mechanisms used by L. pneumophila to gain access to the intracellular environment are not well understood. We have recently isolated three loci, designated enh1,enh2, and enh3, that are involved in the ability of L. pneumophila to enter host cells. One of the genes present in the enh1 locus, rtxA, is homologous to repeats in structural toxin genes (RTX) found in many bacterial pathogens. RTX proteins from other bacterial species are commonly cytotoxic, and some of them have been shown to bind to β2 integrin receptors. In the current study, we demonstrate that the L. pneumophila rtxA gene is involved in adherence, cytotoxicity, and pore formation in addition to its role in entry. Furthermore, an rtxA mutant does not replicate as well as wild-type L. pneumophila in monocytes and is less virulent in mice. Thus, we conclude that the entry genertxA is an important virulence determinant in L. pneumophila and is likely to be critical for the production of Legionnaires' disease in humans.

scholarly journals Clusters of travel associated legionnaires' disease in France, September 2001- August 2003

2004 ◽  
Vol 9 (2) ◽  
pp. 12-13 ◽  
Author(s):  
B Decludt ◽  
C Campese ◽  
◽  
◽  
◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Control Measures ◽  
Local Health ◽  
Surveillance Network ◽  
Health Authorities ◽  
Legionnaires Disease ◽  
Risk Of Exposure ◽  
Local Health Authorities ◽  
Tourist Accommodation ◽  
National Surveillance System

Clusters of travel associated legionnaires' disease warrant urgent attention, and are detected by the French national surveillance system and the European network EWGLINET. Between September 2001 and August 2003, 37 clusters were identified in French tourist accommodation: 27 hotels and 10 campsites. The number of clinical cases per cluster was as follows: 30 clusters of 2 cases (81%), 6 clusters of 3 cases (16%) and one cluster of 4 cases (3%), a total of 82 cases. The local health authorities performed environmental investigations for 36 of the 37 clusters. Among the 36 clusters investigated, water samples were collected for 35. At 16 (46%) sites, Legionella pneumophila was found at a level of more than 103 cfu/litre. In all of the accommodation where risk assessment was found to be inadequate- control measures were implemented immediately. Six hotels were closed immediately following cluster alerts. Comparison of clinical and environmental isolates by pulsed field gel electrophoresis (PFGE) was possible in 3 clusters and identical genomic profiles of the isolates were found in all. During this two year period of surveillance, we found that on many sites there has been a risk of exposure to Legionella. This reinforces the importance of the European surveillance network and the timely notifications of all the cases to EWGLINET.

scholarly journals Lab Diagnosis of Legionnaires’ Disease

JMS SKIMS ◽  
2014 ◽  
Vol 17 (2) ◽  
pp. 50-54
Author(s):  
Nayeem U-Din Wani ◽  
Aamir Ali
Keyword(s):  
Legionella Pneumophila ◽  
Water System ◽  
Laboratory Diagnosis ◽  
Significant Rise ◽  
Control Measures ◽  
Causative Organism ◽  
Common Source ◽  
Contaminated Water ◽  
Atypical Pneumonia ◽  
Legionnaires Disease

Legionnaires’ disease is a multi-system disease which causes atypical pneumonia due to Legionella bacteria, most commonly of the species Legionella pneumophila. About one out of every 10 people who get sick from Legionnaires’ disease will die. Most common source of infection-contaminated water supply through inhalation of contaminated water droplets (aerosols). A laboratory diagnosis of Legionnaires’ disease can be made using a variety of laboratory tests including: culture/isolation of the causative organism, antigen detection in urine, a significant rise in antibody titres or PCR methods. Determination of the monoclonal subtype and molecular sequence typing can support linking between strains from the sampled environment and from patients. The control measures available to reduce the amount of Legionella in a water system include structural adaptations to the water system, temperature control, disinfection using chemicals or other oxidizing materials, and use of biocides or installation of filters. JMS 2014;17(2):50-54

scholarly journals The Role of Sensor-Activated Faucets in Surgical Handwashing Environment as a Reservoir of Legionella

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 446 ◽  
Author(s):  
Marta Mazzotta ◽  
Luna Girolamini ◽  
Maria Rosaria Pascale ◽  
Jessica Lizzadro ◽  
Silvano Salaris ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Risk Environment ◽  
Culture Techniques ◽  
Critical Areas ◽  
Standard Culture ◽  
Healthcare Associated ◽  
Mean Concentration

Surgical handwashing is a mandatory practice to protect both surgeons and patients in order to control Healthcare-Associated Infections (HAIs). The study is focused on Legionella and Pseudomonas aeruginosa contamination in Surgical Handwashing Outlets (SHWOs) provided by sensor-activated faucets with Thermostatic Mixer Valves (TMVs), as correlated to temperature, technologies, and disinfection used. Samples were analyzed by standard culture techniques, comparing hot- and cold-water samples. Legionella isolates were typed by an agglutination test and by mip sequencing. Legionella contamination showed the same distribution between hot and cold samples concerning positive samples and mean concentration: 44.5% and 1.94 Log10 cfu/L vs. 42.6% and 1.81 Log10 cfu/L, respectively. Regarding the distribution of isolates (Legionella pneumophila vs. Legionella non-pneumophila species), significant differences were found between hot- and cold-positive samples. The contamination found in relation to ranges of temperature showed the main positive samples (47.1%) between 45.1–49.6 °C, corresponding to high Legionella concentrations (2.17 Log10 cfu/L). In contrast, an increase of temperature (>49.6 °C) led to a decrease in positive samples (23.2%) and mean concentration (1.64 Log10 cfu/L). A low level of Pseudomonas aeruginosa was found. For SHWOs located in critical areas, lack of consideration of technologies used and uncorrected disinfection protocols may lead to the development of a high-risk environment for both patients and surgeons.

scholarly journals Cationic Porphyrins as Effective Agents in Photodynamic Inactivation of Opportunistic Plumbing Pathogen Legionella pneumophila

2020 ◽  
Vol 21 (15) ◽  
pp. 5367 ◽  
Author(s):  
Andrija Lesar ◽  
Martina Mušković ◽  
Gabrijela Begić ◽  
Martin Lončarić ◽  
Dijana Tomić Linšak ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Tap Water ◽  
Health Hazard ◽  
Acanthamoeba Castellanii ◽  
Water Disinfection ◽  
Cell Membrane Permeability ◽  
Photodynamic Inactivation ◽  
Cationic Porphyrins ◽  
Environmental Bacterium ◽  
Legionnaires Disease

Legionella pneumophila is an environmental bacterium, an opportunistic premise plumbing pathogen that causes the Legionnaires’ disease. L. pneumophila presents a serious health hazard in building water systems, due to its high resistance to standard water disinfection methods. Our aim was to study the use of photodynamic inactivation (PDI) against Legionella. We investigated and compared the photobactericidal potential of five cationic dyes. We tested toluidine blue (TBO) and methylene blue (MB), and three 3-N-methylpyridylporphyrins, one tetra-cationic and two tri-cationic, one with a short (CH3) and the other with a long (C17H35) alkyl chain, against L. pneumophila in tap water and after irradiation with violet light. All tested dyes demonstrated a certain dark toxicity against L. pneumophila; porphyrins with lower minimal effective concentration (MEC) values than TBO and MB. Nanomolar MEC values, significantly lower than with TBO and MB, were obtained with all three porphyrins in PDI experiments, with amphiphilic porphyrin demonstrating the highest PDI activity. All tested dyes showed increasing PDI with longer irradiation (0–108 J/cm2), especially the two hydrophilic porphyrins. All three porphyrins caused significant changes in cell membrane permeability after irradiation and L. pneumophila, co-cultivated with Acanthamoeba castellanii after treatment with all three porphyrins and irradiation, did not recover in amoeba. We believe our results indicate the considerable potential of cationic porphyrins as effective anti-Legionella agents.

scholarly journals Legionella Contamination in Hot Water of Italian Hotels

2005 ◽  
Vol 71 (10) ◽  
pp. 5805-5813 ◽  
Author(s):  
Paola Borella ◽  
Maria Teresa Montagna ◽  
Serena Stampi ◽  
Giovanna Stancanelli ◽  
Vincenzo Romano-Spica ◽  
...  
Keyword(s):  
Risk Factors ◽  
Legionella Pneumophila ◽  
Water Systems ◽  
Hot Water ◽  
Cross Sectional ◽  
Multicenter Survey ◽  
Multivariate Logistic Model ◽  
Legionnaires Disease ◽  
Building Characteristics

ABSTRACT A cross-sectional multicenter survey of Italian hotels was conducted to investigate Legionella spp. contamination of hot water. Chemical parameters (hardness, free chlorine concentration, and trace element concentrations), water systems, and building characteristics were evaluated to study risk factors for colonization. The hot water systems of Italian hotels were strongly colonized by Legionella; 75% of the buildings examined and 60% of the water samples were contaminated, mainly at levels of ≥103 CFU liter−1, and Legionella pneumophila was the most frequently isolated species (87%). L. pneumophila serogroup 1 was isolated from 45.8% of the contaminated sites and from 32.5% of the hotels examined. When a multivariate logistic model was used, only hotel age was associated with contamination, but the risk factors differed depending on the contaminating species and serogroup. Soft water with higher chlorine levels and higher temperatures were associated with L. pneumophila serogroup 1 colonization, whereas the opposite was observed for serogroups 2 to 14. In conclusion, Italian hotels, particularly those located in old buildings, represent a major source of risk for Legionnaires' disease due to the high frequency of Legionella contamination, high germ concentration, and major L. pneumophila serogroup 1 colonization. The possible role of chlorine in favoring the survival of Legionella species is discussed.

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