Copper resistance in Legionella pneumophila: Role of genetic factors and host cells.

Copper is frequently found in drinking water due to its presence in the natural environment and the widespread usage of copper pipes. This toxic metal has a well-known antimicrobial activity, an activity harnessed in copper‑silver ionization (CSI) to eliminate the opportunistic pathogen Legionella pneumophila from engineered water systems. Despite utilizing the antimicrobial properties of copper in Legionella control, little is known about how copper containing environments affect L.

Assessment of monitoring approaches to control Legionella pneumophila within a complex cooling tower system.

Precise and rapid methods are needed to improve monitoring approaches of L. pneumophila (Lp) in cooling towers (CTs) to allow timely operational adjustments and prevent outbreaks. The performance of liquid culture (ASTM D8429-21) and an online qPCR device were first compared to conventional filter plate culture (ISO 11731-2017), qPCR and semi-automated qPCR at three spiked concentrations of Lp (serogroup 1) validated by flow cytometry (total/viable cell count).

Interactions between chaperone and energy storage networks during the evolution of under heat shock.

Waterborne transmission of the bacterium has emerged as a major cause of severe nosocomial infections of major public health impact. The major route of transmission involves the uptake of aerosolized bacteria, often from the contaminated hot water systems of large buildings. Public health regulations aimed at controlling the mesophilic pathogen are generally concerned with acute pasteurization and maintaining high temperatures at the heating systems and throughout the plumbing of hot water systems, but is often able to survive these treatments due to both bacterium-intrinsic and environmental factors.

Draft genome sequences of 13 subsp. isolates from chickens, cows, and Canadian outbreaks.

is the etiological agent responsible for salmonellosis. Here, we report the draft whole genome sequences of 13 . subsp.

Development of heat-shock resistance in modeled by experimental evolution.

Because it can grow in buildings with complex hot water distribution systems (HWDS), healthcare facilities recognize the waterborne bacterium as a major nosocomial infection threat and often try to clear the systems with a pasteurization process known as superheat-and-flush. After this treatment, many facilities find that the contaminating populations slowly recover, suggesting the possibility of evolution favoring increased survival in high-temperature conditions. To mimic this process in a controlled environment, an adaptive laboratory evolution model was used to select a wild-type strain of for survival to transient exposures to temperatures characteristic of routine hot water use or failed pasteurization processes in HWDS.

Detection of Diverse Sequence Types of Legionella pneumophila by Legiolert Enzymatic-Based Assay and the Development of a Long-Term Storage Protocol.

Legiolert is a rapid culture-based enzymatic method for the detection and quantification of Legionella pneumophila in potable and nonpotable water samples. We aimed to assess the ability of this assay to detect diverse sequence types and validated a simple method to preserve samples. We used this assay on 253 potable and 165 nonpotable cooling tower water samples from various buildings in Québec, Canada, and performed sequence-based typing on 96 isolates.

A tail-specific protease is required for intracellular multiplication.

is a Gram-negative bacterium found in natural and man-made water systems where it replicates within amoebas and ciliates. In humans, once inside the lungs, replicates in alveolar macrophages and causes Legionnaires' disease, a severe pneumonia. The Icm/Dot type IVb secretion system is a major virulence factor required for intracellular multiplication.

Toxoflavin secreted by Pseudomonas alcaliphila inhibits the growth of Legionella pneumophila and Vermamoeba vermiformis.

Legionella pneumophila is a natural inhabitant of water systems. From there, it can be transmitted to humans by aerosolization resulting in severe pneumonia. Most large outbreaks are caused by cooling towers colonized with L.

Compromised Effectiveness of Thermal Inactivation of in Water Heater Sediments and Water, and Influence of the Presence of .

Intermittent reduction of temperature set-points and periodic shutdowns of water heaters have been proposed to reduce energy consumption in buildings. However, the consequences of such measures on the occurrence and proliferation of () in hot water systems have not been documented. The impact of single and repeated heat shocks was investigated using an environmental strain of and a reference strain of .

Encapsulation of Russian Olive Water Kefir as an Innovative Functional Drink with High Antioxidant Activity.

Processing of Russian olive water kefir (RWK), as a fermented functional drink made with Russian olive juice and water kefir grains with high antioxidant activity, into powder is crucial for improving its stability for the commercialization of this product. For the first time, this study aimed to encapsulate water kefir microorganisms and bioactive compounds in RWK using carrier materials to develop a synbiotic functional powder using spray drying as an encapsulation method. The goal was maximizing antioxidant activity, product yield, and survival rate of water kefir microorganisms in the produced Russian olive water kefir powder.

Aptamers and Aptamer-Coupled Biosensors to Detect Water-Borne Pathogens.

Aptamers can serve as efficient bioreceptors for the development of biosensing detection platforms. Aptamers are short DNA or RNA oligonucleotides that fold into specific structures, which enable them to selectively bind to target analytes. The method used to identify aptamers is Systematic Evolution of Ligands through Exponential Enrichment (SELEX).

Local Adaptation of Legionella pneumophila within a Hospital Hot Water System Increases Tolerance to Copper.

In large-building water systems, is exposed to common environmental stressors such as copper. The aim of this study was to evaluate the susceptibility to copper of isolates recovered from various sites: two clinical and seven environmental isolates from hot water system biofilm and water and from cooling tower water. After a 1-week acclimation in simulated drinking water, strains were exposed to various copper concentrations (0.

The Tail-Specific Protease Is Important for Legionella pneumophila To Survive Thermal Stress in Water and inside Amoebae.

() is an inhabitant of natural and human-made water systems, where it replicates within amoebae and ciliates and survives within biofilms. When -contaminated aerosols are breathed in, can enter the lungs and may infect human alveolar macrophages, causing severe pneumonia known as Legionnaires' disease. is often found in hot water distribution systems (HWDS), which are linked to nosocomial outbreaks.

The small regulatory RNA Lpr10 regulates the expression of RpoS in Legionella pneumophila.

Legionella pneumophila (Lp) is a waterborne bacterium able to infect human alveolar macrophages, causing Legionnaires' disease. Lp can survive for several months in water, while searching for host cells to grow in, such as ciliates and amoeba. In Lp, the sigma factor RpoS is essential for survival in water.

Unravelling the importance of the eukaryotic and bacterial communities and their relationship with Legionella spp. ecology in cooling towers: a complex network.

Background: Cooling towers are a major source of large community-associated outbreaks of Legionnaires' disease, a severe pneumonia. This disease is contracted when inhaling aerosols that are contaminated with bacteria from the genus Legionella, most importantly Legionella pneumophila. How cooling towers support the growth of this bacterium is still not well understood.

strain isolated from a human: A case report and whole genome sequencing analysis.

We describe a strain of isolated from a bronchoalveolar lavage specimen from an 83-year-old patient in the province of Québec. Identification was done using 16S rRNA sequencing. The strain could replicate efficiently in human THP-1 macrophages and maintained a low level of cytotoxicity.

Identification of two aptamers binding to Legionella pneumophila with high affinity and specificity.

Legionella pneumophila (Lp) is a water borne bacterium causing Legionnaires' Disease (LD) in humans. Rapid detection of Lp in water system is essential to reduce the risk of LD outbreaks. The methods currently available require expert skills and are time intensive, thus delaying intervention.

Presence of Legionella spp. in cooling towers: the role of microbial diversity, Pseudomonas, and continuous chlorine application.

Legionnaires' disease (LD) is a severe pneumonia caused by several species of the genus Legionella, most frequently by Legionella pneumophila. Cooling towers are the most common source for large community-associated outbreaks. Colonization, survival, and proliferation of L.

Legionella pneumophila levels and sequence-type distribution in hospital hot water samples from faucets to connecting pipes.

Recent studies have reported increased levels of Legionella pneumophila (Lp) at points of use compared to levels in primary and secondary components of hot water systems, suggesting possible selection by environmental conditions. In this study, concentrations of Lp in a hospital hot water system were evaluated by profile sampling, collecting successive water samples to determine the prevalence at the faucet (distal) and upstream piping before and after a system intervention to increase temperature. Lp strain diversity was compared between different points of use and different areas of the hot water system (i.

Quantification of Viable but Non-Culturable Cells of Legionella pneumophila.

Legionella pneumophila, among other bacteria, may enter a viable but non-culturable state as a means for survival in stressful conditions. Bacterial cells in the viable but non-culturable state cannot grow on standard medium; however, they continue to exhibit characteristics that are associated with live cells, such as respiration, transcription, and cell wall integrity. The present paper outlines a detailed protocol for the detection of viable but non-culturable L.

The Virulence Effect of CpxRA in Is Independent of the Auxiliary Proteins NlpE and CpxP.

is a murine pathogen used to model the intestinal infection caused by Enteropathogenic and Enterohemorrhagic (EPEC and EHEC), two diarrheal pathogens responsible for morbidity and mortality in developing and developed countries, respectively. During infection, these bacteria must sense and adapt to the gut environment of the host. In order to adapt to changing environmental cues and modulate expression of specific genes, bacteria can use two-component signal transduction systems (TCS).