Presence Of Legionella Research Articles

Legionella and legionellosis in touristic-recreational facilities: Influence of climate factors and geostatistical analysis in Southern Italy (2001–2017)

Legionella is the causative agent of Legionnaires' disease, a flu-like illness normally acquired following inhalation or aspiration of contaminated water aerosols. Our recent studies revealed that climatic parameters can increase the number of reported cases of community-acquired Legionnaires' disease. Here, we evaluated the presence of Legionella in water networks and the distribution of Legionnaires' disease cases associated with touristic-recreational facilities in the Apulia region (southern Italy) during the period 2001–2017 using geostatistical and climatic analyses. Geostatistical analysis data revealed that the area with the highest concentration of Legionella in water systems also had the greatest number of cases of Legionnaires' disease associated with touristic-recreational facilities. Climatic analysis showed that higher daily temperature excursion (difference between maximum and minimum temperature) on the day of sampling was more often associated with Legionella-positive samples than Legionella-negative samples. In addition, our data highlighted an increased risk of Legionnaires’ disease with increases in precipitation and average temperature and with decreases in daily temperature excursion (difference between maximum and minimum temperature over the course of 24 h in the days of incubation period of disease) and minimum temperature.Healthcare professionals should be aware of this phenomenon and be particularly vigilant for cases of community-acquired pneumonia during such climatic conditions and among the tourist population. The innovative geo-statistical approach used in this study could be applied in other contexts when evaluating the effects of climatic conditions on the incidence of Legionella infections.

Environmental surveillance and spatio-temporal analysis of Legionella spp. in a region of northeastern Italy (2002-2017).

Legionella spp. are considered an important cause of potentially preventable morbidity and mortality, making environmental surveillance a crucial component of risk assessment plans. In this work, 20,319 water samples were collected in 3,983 environmental surveys during a 16-year period by ARPA, the Regional Agency for Environmental Protection, Friuli Venezia Giulia, and the results were studied to better understand the diffusion mechanisms of Legionella. The data showed a strong seasonal signal, a prevalence of L. pneumophila serogroup 2–15 in most environments (63% of positive samples), a prevalence of L. pneumophila serogroup 1 in swimming pool-associated environments (82% of positive samples), a persistent presence of Legionella in hospitals and a recurrent presence of Legionella in other facilities such as hotels, possibly years after interventions, highlighting the difficulty of eradicating the bacteria. Retrospective spatio-temporal analyses on geocoded historical data were carried out with SaTScan using an ordinal model with risk as a covariate to identify potential clusters with an excess of cases in the higher-risk categories. Although no outbreaks occurred during the period of study, such analyses identified spatially restricted zones with unusual contamination, which sometimes were also areas in which several surveys triggered by notifications of clinical cases were performed. Simulations of periodic prospective analyses permitted the assessment of the efficacy of the method in early detection of such clusters. The proposed method may be a useful tool in environmental surveillance, prevention and control of Legionella.

Colonization by Pseudomonas aeruginosa of dental unit waterlines and its relationship with other bacteria: suggestions for microbiological monitoring.

Pseudomonas aeruginosa is an environmental bacterium, ubiquitous in aquatic habitats and water distribution systems, including dental unit waterlines (DUWLs). We investigated the prevalence of P. aeruginosa in DUWLs from private dental settings. We also analyzed the relationship between P. aeruginosa contamination and the presence of Legionella spp. and total viable count (TVC) in order to suggest a simple and inexpensive protocol to test the quality of water from DUWLs. We detected and quantified P. aeruginosa both by culture and by a PMA (propidium monoazide)-qPCR method. Overall, we detected P. aeruginosa in 17 samples using the PMA-qPCR and in 11 samples using the culture. All culture-positive samples were positive with the PMA-qPCR too, with an agreement between the two methods of 93% and a Cohen's kappa coefficient of κ = 0.747 (good concordance). Comparing results with results of our previous study, we noted that (a) P. aeruginosa was isolated only from DUWLs with high TVC and (b) five out of six Legionella-positive samples were negative for Pseudomonas spp. Our final suggestion is that the cleanliness of DUWLs should be assessed by TVC because it is a good indicator of the presence of pathogens such as Legionella spp. and P. aeruginosa.

Environmental Surveillance of Legionellosis within an Italian University Hospital-Results of 15 Years of Analysis.

Legionnaires’ disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large and old buildings, such as hospitals, can be contaminated with legionellae and therefore represent a potential risk for the hospital population. In this study, we demonstrated the constant presence of Legionella in water samples from the water system of a large university hospital in Messina (Sicily, Italy) consisting of 11 separate pavilions during a period of 15 years (2004–2018). In total, 1346 hot water samples were collected between January 2004 and December 2018. During this period, to recover Legionella spp. from water samples, the standard procedures reported by the 2000 Italian Guidelines were adopted; from May 2015 to 2018 Italian Guidelines revised in 2015 (ISS, 2015) were used. Most water samples (72%) were positive to L. pneumophila serogroups 2–14, whereas L. pneumophila serogroup 1 accounted for 18% and non-Legionella pneumophila spp. Accounted for 15%. Most of the positive samples were found in the buildings where the following critical wards are situated: (Intensive Care Unit) ICU, Neurosurgery, Surgeries, Pneumology, and Neonatal Intensive Unit Care. This study highlights the importance of the continuous monitoring of hospital water samples to prevent the potential risk of nosocomial legionellosis.

Legionella co-infection in HIV-associated pneumonia

Due to poor diagnostics and increased co-infections, HIV-associated Legionella infections are underreported. We aimed to retrospectively determine the frequency of Legionella infections in bronchoalveolar lavage (BAL) from HIV-associated pneumonia patients hospitalized in Medellin, Colombia, between February 2007 and April 2014. Although culture was negative, 17 BAL (36%) were positive for Legionella by quantitative polymerase chain reaction, most of which were in the Mycobacterium tuberculosis or Pneumocystis jirovecii co-infected patients, and included L. anisa (n = 6), L. bozemanae (n = 4), L. pneumophila (n = 3), and L. micdadei (n = 2). All L. bozemanae and L. micdadei associated with Pneumocystis, while all L. pneumophila associated with M. tuberculosis. Legionella probable cases had more complications and higher mortality rates (P = 0.02) and were rarely administered empirical anti-Legionella therapy while in hospital. Clinicians should be aware of the possible presence of Legionella in HIV and M. tuberculosis or P. jirovecii co-infected patients.

A potential source of undiagnosed Legionellosis: Legionella growth in domestic water heating systems in South Africa

Legionella is a genus of pathogenic bacterial mesophiles that cause a range of diseases collectively referred to as Legionellosis, with immuno-compromised individuals being particularly susceptible. Water heaters, a potential domestic niche for these pathogens, are heavy energy consumers, causing cost-sensitive users to employ energy-saving initiatives, such as scheduling and lower temperature set points. However, lower water temperatures allow Legionella to flourish. This paper uses computational fluid dynamics modelling to show that a horizontal electric water heater provides an environment that is conducive to Legionella growth, although its prevalence is probably higher in the downstream pipes. The presence of Legionella in water heaters is established through water sampled from five in-field water heaters, of which the temperatures and heating schedules are known. Microbiological techniques (PCR and weight-based qRT-PCR) are used to assess the presence of Legionella and L. pneumophila at point-of-use taps. A model is used to determine the potential infection rate from these concentrations, demonstrating that undiagnosed Legionellosis infection is likely. In low- and middle-income countries, like South Africa, misdiagnosis of Legionellosis may be common due to the shadow cast by HIV and TB prevalence.

Targeted Metagenomics of Microbial Diversity in Free-Living Amoebae and Water Samples.

The presence of Legionella spp. in natural and man-made water systems is a great public health concern and heavily depends on the presence of free-living amoebae. Taking advantage of the development and affordability of next-generation sequencing technology, we present here a method to characterize the whole bacterial community directly from water samples, as well as from isolated free-living amoebae.

Legionella sp. in water systems in public teaching and education facilities in Małopolskie voivodeship in 2016

Bacteria Legionella sp. found in water distribution systems, especially warm, transferred to water spray devices for aerators and showers in the form of aerosols infected with them become a threat to the human inhaler. Assessment of colonization of the water supply network with Legionella bacteria in teaching and education facilities in Małopolska in 2016 year. The results of water samples taken from plumbing installations were analyzed in teaching and education facilities by employees of the State Sanitary Inspection of the Lesser Poland Voivodeship. The results of 366 testing hot water samples in 111 teaching and education centers in Małopolska have shown that in 123 testing samples (33,6%) in 48 centers (43,2%) the water sample was colonized with Legionella sp. and the water quality did not meet the requirements of the current ordinance of the Minister of Health. It is justified to periodically monitor the presence of Legionella sp. in water supply installations in teaching and education centers and taking action to reduce the colonization of these bacteria.

Detection of amoeba-associated Legionella pneumophila in hospital water networks of Johannesburg

The prevalence of free-living amoeba and associated Legionella spp. in hospital water systems may pose a risk of Legionnaires’ disease to immuno-compromised patients. This study investigated the occurrence of amoeba-associated Legionella pneumophila in three South African hospital water systems. A total of 98 water and/or biofilm samples were collected from the sterilisation unit, theatres, neonatal ward and intensive care units. Amoebae were isolated from 71 (72.4%) samples. Isolated amoebae were analysed using qPCR and culture methods to test for the presence of Legionella. L. pneumophila did not grow on selective media in any of the samples. A total of 7 out of the 71 (9.9%) amoeba-positive samples showed a positive reaction for L. pneumophila using qPCR. Although relatively few samples were positive for Legionella in this preliminary study, the association with amoeba still presents a potential public health risk to immuno-compromised patients when exposed to contaminated water.

Detection of Legionella Anisa in Water from Hospital Dental Chair Units and Molecular Characterization by Whole-Genome Sequencing.

This study aims to assess contamination with Legionella spp. in water from dental chair units (DCUs) of a hospital dental ward and to perform its molecular characterization by whole-genome sequencing (WGS). We collect eight water samples (250 mL) from four DCUs (sink and water-syringe). Samples are tested for the presence of Legionella spp. (CFUs/mL) by culturing according to the Nederland Norm (NEN) 6265. Three DCUs are found positive for Legionella anisa, and four isolates are cultured (sink n = 2, water-syringe n = 1; two isolates from the same chair) with 1 × 102 CFU/mL. Whole-genome multi-locus sequence typing (wgMLST) results indicate that all strains belong to the same cluster with two to four allele differences. Classical culture combined with WGS allows the identification of a unique clone of L. anisa in several DCUs in the same hospital dental ward. This may indicate a common contamination source in the dental unit waterlines, which was fixed by replacing the chairs and main pipeline of the unit. Our results reveal tap water contamination in direct contact with patients and the usefulness of WGS to investigate bacterial molecular epidemiology.

The presence and prevalence of Legionella spp in collected rainwater and its aerosolisation during common gardening activities.

To determine the presence and prevalence of Legionella spp in domestic rainwater storage butts and to quantify its aerosolisation when collected rainwater is used for common gardening activities. Volunteers were asked to take a water sample from their garden rainwater storage butt. The presence of Legionella was determined using quantitative polymerase chain reaction (qPCR). Two new rainwater storage butts were installed on-site at PHE Porton and positioned in sunlight or in the shade. Ambient conditions and those within the two 'experimental' water butts were continually monitored. A cyclone air sampler was used to detect the presence of Legionella in the air when collected rainwater was poured from a watering can or delivered via a hosepipe attached to a submersible water butt pump. A total of 63 volunteers provided water samples from 113 different rainwater storage butts. Legionella spp was detected in 107 of these samples at a mean concentration of 4.7 × 104 genomic units l-1. Two of these samples also contained L. pneumophila. The water butt positioned in the shade stored water at a significantly lower temperature than that exposed to sunlight. While the concentration of Legionella was significantly higher in this cooler water, meteorological conditions rather than conditions within the water butt had the greatest effect upon Legionella concentration. No Legionella was detected in the air when rainwater was poured from a watering can. However, using a hose pipe on a 'fine spray' setting increased both the number of organisms detected in the air and their dissemination. In this study, Legionella spp were common contaminants of collected rainwater. However, the use of rainwater for common gardening activities should not be discouraged. Aerosolisation of Legionella when using a watering can is minimal and any increased risk associated with hose pipe use can be mitigated by using a coarse spray setting.

Prevalence of Legionella in retirement homes and group homes water distribution systems

BackgroundAlthough historically the focus has been placed above all on hospital infections and travel-associated outbreaks, most of the cases of Legionella infection are sporadic and occur in community-dwellers. ObjectivesTo evaluate the presence and load of Legionella in hot water systems of non-healthcare facilities that host closed communities. Furthermore, we tried to verify the association between Heterotrophic Plate Counts (HPCs) and presence of Legionella. MethodsWe collected hot water and biofilm samples from the showerheads of retirement homes and group homes. Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. We determined the HPCs at 22 and 37 °C by the pour plate method. Statistics performed through STATA. ResultsWe collected 140 hot water and biofilm samples, 95 from 26 retirement homes and 35 from 9 group homes. Legionella was found in 36.8% samples collected from retirement homes and only in 10.3% group homes' samples (p = 0.01). Legionella was identified more frequently in water than in biofilm (29.8% vs 16.9%); just in one case the pathogen was found in the biofilm only. L. pneumophila sg 1 was the pathogen more frequently isolated (65.8%), with an average load of 2720 CFU/L (SD = 8393 CFU/L). We have often noticed a high microbial contamination (67% of HPCs >200 CFU/mL) and identified a higher prevalence of Legionella for intermediate values of HPC 22 °C (p = 0.011). 32% of people hosted in retirement homes were exposed to Legionella. ConclusionsColonization of water-systems of retirement homes and group homes is anything but occasional, and in our survey it mainly affects the former, moreover often due to L. pneumophila sg 1. The search for the pathogen in the biofilm has proved to be of little use. The relationship between HPC and Legionella deserves further studies.

Występowanie pałeczek Legionella sp. w instalacjach ciepłej wody użytkowej w obiektach hotelarskich na terenie województwa świętokrzyskiego

Legionella sp. contamination in hot water systems in hotels in the ŚwiętokrzyskieVoivodshipIntroduction: In the European Union countries there were detected 6933 cases of legionellosis Legionnaires’ disease in 2014. The disease is caused by Legionella sp. bacteria, which are responsible for Legionella sp. pneumonia infection and common in both natural and artificial water environments. If there is proper temperature and nutrients, the bacteria multiply rapidly in artificial environments hot water systems, central air conditioning systems, and medical devices, posing a risk to human health.Aims: This study was conducted to quantify the frequency of contamination with Legionella sp. of hot water systems in some hotels in the Świętokrzyskie Voivodeship.Materials and methods: 228 buildings 103 hotels and 125 other types of lodging were investigated in the years 2009–2015, 1414 samples were collected which were later analyzed by membrane filtration technique in the laboratories of the State Sanitary Inspection in the Świętokrzyskie Voivodeship, conforming to the methods of PN-ISO 11731-2:2008.Results: Legionella sp. was detected in 30.3% of the hot water systems investigated. The problem of bacteria colonization was more frequent in the hotel buildings 41.2% that in other types of lodging 20.8%. In 34 hotels and 20 other buildings the level of contamination was medium Legionella sp. 100–1000 CFU/100 ml sample, and in 9 hotel and 6 other buildings the contamination was high Legionella sp. 1000–10000 CFU/100 ml sample. In general out of 1414 collected samples, medium and high contamination with Legionella sp. was detected in 272 samples 19.2%.Conclusions: The results obtained in the study confirm an overall presence of Legionella sp. in hot water systems of hotels and other lodgings in the Świętokrzyskie Voivodeship. Having analyzed the data from the years 2009–2015, there may be observed a slight decline in the frequency of contamination in the recent years. Nonetheless, it is alarming that despite a periodic control system at some of the locations, the level of contamination is still signifi cant.

Presence of Legionella spp. in human dental plaque.

The aim of this research is to verify the presence of Legionella in human dental plaque. 65 adult patients not treated with systemic or local antibiotics at least 2 months before the time of sample collection were enrolled for plaque collection between September 2015 and December 2016. A brief questionnaire about lifestyle and health risks was administered. Legionella spp. detection has been executed by semi- nested PCR. 8 out of 65 plaque samples (12.3%) were positive for Legionella spp. As regards health risks and lifestyle aspects, no relevant difference was observed between patients involved in our study, except for two positive patients who have reported a COPD ongoing and a pneumonia in the past. This study represents a step forward in the knowledge of reservoirs of the microorganism and richness of oral microbiota.

Detection of Legionella spp. in Public Hospitals Water Supplies in Lattakia-Syria

The present study was designed to evaluate the occurrence of Legionella spp. contamination in water taps and water tanks of public hospitals, Lattakia, Syria. It is the first study about Legionella in Syria. One hundred and thirty swabs from water taps and 26L of water from water tanks of seven hospitals were collected and detected for the presence of Legionella spp. by using GVPC, BCYE, BCY agar. The results were 49 of 130 (37.69%) water tap samples which were positive for Legionella spp, and most water tank samples were positive for Legionella spp.,too . In conclusion, Legionella spp. are present in aquatic hospitals environment of Lattakia, Syria, so hospital water systems may be the primary reservoirs for Legionnaires’ disease. Due to the serious risk of infections, it is better to make efforts to eliminate Legionella spp. in water supplies in Hospitals.

THE RISK ASSESMENT AND IMPACT OF HYGIENIC CONDITIONS ON THE DEVELOPMENT OF LEGIONELLA SPP. IN WATER SYSTEMS OF PUBLIC AND TOURIST FACILITIES

A large number of different diseases are associated with the consumption of hygienic defective water and the use of water for maintaining personal hygiene. Recreational waters, water in systems intended for cooling and heating of public buildings are also significant. Among these diseases, the most significant is legionellosis, the disease which has become more and more important in the whole world in recent years. The aim of this paper was to evaluate the connection of hygienic conditions in public buildings with the appearance of genus Legionella in drinking and bathing water, as well as water from outside and inside fountains, pools and water from cooling and heating systems for public buildings. Obtained results are also used to evaluate the risk of developing legionellosis in the population of Bosnia and Herzegovina and among foreign tourists. The presence of Legionella spp. was analysed in 238 samples of water taken from faucets in rooms of buildings intended for people's accommodation, in open and closed fountains, pools, cooling and water systems. Hygienic conditions in the facilities were assessed using survey questionnaire and complemented with legionella findings. This study showed the direct correlation between hygienic conditions in public and tourist facilities with the presence of Legionella spp. in the waters taken in these objects.

Presence of Legionella spp. in Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

Although the European reports highlight an increase in community-acquired Legionnaires’ disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or on the first floor and on the last floor, while the potable water quality was analysed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remote tap. Legionella pneumophila sg1, Legionella pneumophila sg2–16, and non-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease and/or the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 °C and 37 °C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control.

Phylogenetic Analysis and Antimicrobial Profiles of Cultured Emerging Opportunistic Pathogens (Phyla Actinobacteria and Proteobacteria) Identified in Hot Springs.

Hot spring water may harbour emerging waterborne opportunistic pathogens that can cause infections in humans. We have investigated the diversity and antimicrobial resistance of culturable emerging and opportunistic bacterial pathogens, in water and sediment of hot springs located in Limpopo, South Africa. Aerobic bacteria were cultured and identified using 16S ribosomal DNA (rDNA) gene sequencing. The presence of Legionella spp. was investigated using real-time polymerase chain reaction. Isolates were tested for resistance to ten antibiotics representing six different classes: β-lactam (carbenicillin), aminoglycosides (gentamycin, kanamycin, streptomycin), tetracycline, amphenicols (chloramphenicol, ceftriaxone), sulphonamides (co-trimoxazole) and quinolones (nalidixic acid, norfloxacin). Gram-positive Kocuria sp. and Arthrobacter sp. and gram-negative Cupriavidus sp., Ralstonia sp., Cronobacter sp., Tepidimonas sp., Hafnia sp. and Sphingomonas sp. were isolated, all recognised as emerging food-borne pathogens. Legionella spp. was not detected throughout the study. Isolates of Kocuria, Arthrobacter and Hafnia and an unknown species of the class Gammaproteobacteria were resistant to two antibiotics in different combinations of carbenicillin, ceftriaxone, nalidixic acid and chloramphenicol. Cronobacter sp. was sensitive to all ten antibiotics. This study suggests that hot springs are potential reservoirs for emerging opportunistic pathogens, including multiple antibiotic resistant strains, and highlights the presence of unknown populations of emerging and potential waterborne opportunistic pathogens in the environment.

Comment on Montagna, et al. Evaluation of Legionella air contamination in healthcare facilities by different sampling methods: An Italian multicenter study. Int. J. Environ. Res. Public Health 2017, 14, 670.

In their recent article, Montagna et al. describe a multicenter study investigating the presence of Legionella in water and air samples of Italian healthcare facilities [1].[...]

The effect of temperature and chlorine residual on the presence of Legionella spp. in water systems of public and tourist facilities

Introduction: Legionella bacteria are ubiquitous microorganisms mostly found in artificial water environments, especially those which produce aerosol, such as swimming pools, saunas, and spas. Development of Legionella depends on several factors, including water temperature and chlorine. The aim of this study was to evaluate the occurrence of Legionella spp. to the temperature and free residual chlorine in tap water, water from fountains, swimming pools, cooling and heating systems.
 Methods: We collected 238 samples of water taken from different places and analyzed the presence of Legionella spp. by BAS EN ISO 11731-2:2009 - Water quality – Detection and enumeration of Legionella - Part 2: A direct membrane filtration method for waters with low bacterial counts, as samples were the waters with low expectancy of bacterial contamination compared to the temperature and free residual chlorine. The X2 test was used to show statistical significance.
 Results: Legionella spp. was detected in 18.62% of tap water and in 8.82% samples of water taken from fountains, swimming pools, and cooling and heating systems. The highest number of positive samples were detected in waters with the temperature higher than 20°C and lower than 50°C. The highest number of positive samples were reported by the concentration of free residual chlorine lower than 0.2 mg/l. The X2 test showed a statistically significant difference between positive and negative results for the presence of Legionella spp. among three groups of water samples.
 Conclusion: The research has shown a connection between environmental factors and the presence of Legionella spp. in the water systems of public and tourist facilities.