Distribution Of Legionella Research Articles

Legionella pneumonia as a rising public health threat in Argentina: Is it the time to worry?

Legionella pneumonia as a rising public health threat in Argentina: Is it the time to worry?

Serotyping of Legionella Bacteria Isolated from Various Water Systems in the Central Anatolia Region

Objective: Legionella bacteria are waterborne environmental pathogens that are considered a public health problem because they cause Legionnaires' disease, which is a nationally notifiable disease. Materials and Methods: Legionella analysis was performed in a total of 651 water samples collected during the years 2015 (450) – 2016 (201). Water samples were collected from hospitals (64.66%), hotels (15.05%), the automotive industry (14.43%) and from the buildings (5.83%) in the Central Anatolia Region. After the isolation of Legionella by the filtration and culturing method, serogroup and subtypes were determined via latex agglutination tests and the direct fluorescent antibody method. Results: In 2015, the Legionella positivity rate was 8.6%, where 28.2% of detections were from L. pneumophila serogroup-1. Six isolates were found to be Philadelphia, four were Olda, and one was Bellingham subgroup. Overall, 64.1% were L. pneumophila serogroup 2-14. Moreover, 14 isolates were SG-5, 10 were SG-6, and one was SG-10. 7.7% were unidentified Legionella species. The Legionella species identified were L. micdadei and L. longbeachae. In 2016, the Legionella positivity rate was 10.4%, with 28.6% of them being from L. pneumophila serogroup-1. Four were found to be Olda and two were Philadelphia subgroups. Overall, 66.6% of them were L. pneumophila serogroup 2-14. Moreover, six of them were SG-5, four were SG-6, and four were SG-2. 4.7% were unidentified Legionella species. There was only one species detected as L. micdadei. Conclusions: It has been observed that the distribution of Legionella has exhibited diversity in different water systems throughout the Central Anatolia Region.

Presence of Viable, Clinically Relevant Legionella Bacteria in Environmental Water and Soil Sources of China.

ABSTRACTThe distribution of pathogenic Legionella in the environmental soil and water of China has not been documented yet. In this study, Legionella was detected in 129 of 575 water (22.43%) and 41 of 442 soil samples (9.28%) by culture. Twelve Legionella species were identified, of which 11 were disease-associated. Of the Legionella-positive samples, 109 of 129 (84.50%) water and 29 of 41 (70.73%) soil were positive for L. pneumophila, which accounted for about 75% of Legionella isolates in both water and soil, suggesting L. pneumophila was the most frequent species. Soil showed a higher diversity of Legionella spp. as compared with water (0.6279 versus 0.4493). In contrast, serogroup (sg) 1 was more prevalent among L. pneumophila isolates from water than from soil (26.66% versus 12.21%). Moreover, many disease-associated sequence types (STs) of L. pneumophila were found in China. Intragenic recombination was acting on L. pneumophila from both water and soil. Phylogeny, population structure, and molecular evolution analyses revealed a probable existence of L. pneumophila isolates with a special genetic background that is more adaptable to soil or water sources and a small proportion of genetic difference between water and soil isolates. The detection of viable, clinically relevant Legionella demonstrates soil as another source for harboring and dissemination of pathogenic Legionella bacteria in China. Future research should assess the implication in public health with the presence of Legionella in the soil and illustrate the genetic and pathogenicity difference of Legionella between water and soil, particularly the most prevalent L. pneumophila.IMPORTANCE Pathogenic Legionella spp. is the causative agent of Legionnaires’ disease (LD), and L. pneumophila is the most common one. Most studies have focused on L. pneumophila from water and clinical samples. However, the soil is another important reservoir for this bacterium, and the distribution of Legionella spp. in water and soil sources has not been compared and documented in China yet. Discovering the distribution of Legionella spp. and L. pneumophila in the two environments may help a deep understanding of the pathogenesis and molecular evolution of the bacterium. Our research systematically uncovered the distributions of Legionella spp. in different regions and sources (e.g., water and soil) of China. Moreover, phylogeny, population structure, and molecular evolution study revealed the possible existence of L. pneumophila with a special genetic background that is more adaptable to soil or water sources, and genetic difference may exist.

Isolation and identification of Legionella spp. from non-hospital facilities: a preliminary one-year surveillance study in the urban area of Pesaro-Urbino (Central Italy).

Legionella is considered one of the most important causes of potentially preventable morbid-ity and mortality. These microorganisms are ubiquitous, but incomplete information is available on the geographic distribution of Legionella species in our region. For the mentioned reasons, in this work the distribution of Legionella spp. in non-hospital facilities of the urban area of Pesaro-Urbino (Central Italy), including public fountains, residential build-ings, public and private offices and retirement homes, was investigated. A total of 298 water samples were collected from the different facilities and subjected to standard Legionella isolation and identification protocols. As reported, 17.8% of the collected water samples resulted positive for Legionella spp. (28.6% from retirement homes, 21.3% from residential buildings, 15.3% from private and public offices). The highest per-centage of positive samples (14.4%) was found in hot water from retirements homes (58.8%) and residential buildings (31.8%); the most frequent isolated serogroups were L. pneumophila 2-14 (71.7%). This work is the first describing the distribution of Legionella spp. in non-hospital facilities in the province of Pesaro-Urbino, and highlights a condition of potential risk for susceptible categories. From our data, we can point that a regular and constant control to prevent microbiological risk from legionellosis, particularly in facilities housing the elderly, is recommended.

Occurrence of Legionella spp. in Man-Made Water Sources: Isolates Distribution and Phylogenetic Characterization in the Emilia-Romagna Region.

Legionella species distribution in the Emilia-Romagna region, involving hospital (H) and community (C) environments, was conducted. Legionella culture, agglutination test, and mip-gene sequencing were applied on 240 isolates. The analysis showed a higher prevalence of non-Legionella pneumophila (n-Lp) species (84.1%) compared with L. pneumophila (Lp) (15.9%), with a higher frequency of n-Lp with respect to Lp species in both environments (77.6% and 96.4%, in H and C, respectively). The Shannon index showed a significant difference in Legionella distribution (p = 0.00017), with a significant abundance of Lp in the H compared with C environment (p = 0.00028). The continuous disinfection treatment in H could contribute to adaptive survival of the Lp species. Phylogenetic analysis revealed a conservative clade distribution between H and C: L. feeleii clade with three subclades in C and the Lp clade with five subclades in H and two in C, respectively. Our findings suggest the importance of Legionella surveillance both in H and C, with a focus on n-Lp species less connected to human disease. The Legionella prevalence and diversity found here indicate that geographical and temporal isolate evolution should be considered during surveillance, particularly in the light of global warming and changes in population risk factors.

How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience.

In this study, we aimed to associate the molecular typing of Legionella isolates with a culture technique during routine Legionella hospital environmental surveillance in hot water distribution systems (HWDSs) to develop a risk map able to be used to prevent nosocomial infections and formulate appropriate preventive measures. Hot water samples were cultured according to ISO 11731:2017. The isolates were serotyped using an agglutination test and genotyped by sequence-based typing (SBT) for Legionella pneumophila or macrophage infectivity potentiator (mip) gene sequencing for non-pneumophila Legionella species. The isolates’ relationship was phylogenetically analyzed. The Legionella distribution and level of contamination were studied in relation to temperature and disinfectant residues. The culture technique detected 62.21% of Legionella positive samples, characterized by L. pneumophila serogroup 1, Legionella non-pneumophila, or both simultaneously. The SBT assigned two sequence types (STs): ST1, the most prevalent in Italy, and ST104, which had never been isolated before. The mip gene sequencing detected L. anisa and L. rubrilucens. The phylogenetic analysis showed distinct clusters for each species. The distribution of Legionella isolates showed significant differences between buildings, with a negative correlation between the measured level of contamination, disinfectant, and temperature. The Legionella molecular approach introduced in HWDSs environmental surveillance permits (i) a risk map to be outlined that can help formulate appropriate disinfection strategies and (ii) rapid epidemiological investigations to quickly identify the source of Legionella infections.

Effect of ClO2 on the distribution of Legionella pneumophila serogroups in a Teaching Hospital

Abstract The prevention of Legionella colonization of water systems is one of the goals of hospital management. Among chemical disinfection methods, chlorine dioxide (ClO2) has been largely used to control Legionella in water systems. We analysed the distribution of Legionella pneumophila serogroups (sg) and Legionella other spp before (PRE) and after (POST) installation of chlorine dioxide (ClO2) continuous disinfection systems in a Teaching Hospital in Rome. According to the Italian National Guidelines, our surveillance plan involved a systematic sampling of the water system. The sampling was performed from Jan. 2010 to Dec. 2019. From 2011 to 2019, ClO2 continuous disinfection systems were installed in all hot water system of the hospital, and maintained at a concentration of 0.25 mg/l at the end point. The isolated strains of Legionella were first serotyped using a kit that identifies sg1, other species and that discriminate sg from 2 to 15. 1505 hot water samples were collected from the Hospital and analysed. 363 samples are PRE and 1142 are POST activation of ClO2. Only the 16.74% of monitored sampling points were colonized by Legionella during the study period. This percentage decrease from 31.40% of PRE samples, to 12.08% of POST samples (p ≤ 0.000). The sg isolated were: sg3 (60.31%), sg8 (17.12%), sg1 (16.73%), sg6 (1.95%) and other species (3.89%). Comparing the distribution of sg between the PRE and POST samples, the sg8 showed a high increase (+136.84%) and the sg3 a slight decrease (-17.94%). These variations were statistically significative. The results showed a predominance of Legionella pneumophila sg3, compared to what was observed in a multicenter study conducted between different hospitals of various regions of Italy, where sg6 was the major isolate. The ClO2 affect the distribution of sg, in particular for sg8. This interesting result will be further investigated. Key messages Our data deriving from an environmental monitoring plan, show that the ClO2 affects the distribution of Legionella’s serogroups. The ClO2 reduces the percentage of samples colonized by Legionella. The ClO2 reduces the percentage of samples colonized by Legionella.

Human Anti-Lipopolysaccharid (LPS) antibodies against Legionella with high species specificity.

Legionella are Gram-negative bacteria that are ubiquitously present in natural and man-made water reservoirs. When humans inhale aerosolized water contaminated with Legionella, alveolar macrophages can be infected, which may lead to a life-threatening pneumonia called Legionnaires' disease. Due to the universal distribution of Legionella in water and their potential threat to human health, the Legionella concentration in water for human use must be strictly monitored, which is difficult since the standard detection still relies on lengthy cultivation and analysis of bacterial morphology. In this study, an antibody against L. pneumophila has been generated from the naïve human HAL antibody libraries by phage-display for the first time. The panning was performed on whole bacterial cells in order to select antibodies that bind specifically to the cell surface of untreated Legionella. The bacterial cell wall component lipopolysaccharide (LPS) was identified as the target structure. Specific binding to the important pathogenic L. pneumophila strains Corby, Philadelphia-1 and Knoxville was observed, while no binding was detected to seven members of the families Enterobacteriaceae, Pseudomonadaceae or Clostridiaceae. Production of this antibody in the recombinant scFv-Fc format using either a murine or a human Fc part allowed the set-up of a sandwich-ELISA for detection of Legionella cells. The scFv-Fc construct proved to be very stable, even when stored for several weeks at elevated temperatures. A sensitivity limit of 4,000 cells was achieved. The scFv-Fc antibody pair was integrated on a biosensor, demonstrating the specific and fast detection of L. pneumophila on a portable device. With this system, 10,000 Legionella cells were detected within 35 min. Combined with a water filtration/concentration system, this antibody may be developed into a promising reagent for rapid on-site Legionella monitoring.

Occurrence of Legionella in groundwater used for sprinkler irrigation in Southern Italy

Legionellae are opportunistic bacteria that cause various conditions after exposure to contaminated aerosols, ranging from a serious type of pneumonia to a mild case of an influenza-like illness. Despite the risks of exposure, little is known about the occurrence of Legionella in natural environments and, even though studies have shown that there is a potential risk of transmission via inhalation, it does not have to be detected in groundwater that is used for irrigation. The culture methods traditionally used to detect Legionella have several limits that can be partly solved by applying molecular techniques.Samples from 177 wells in Apulia, Southern Italy, were collected twice, in winter and in summer, and analyzed. When compared with the guidelines, 145 (81.9%) of the sampled wells were suitable for irrigation use. The culture-based method highlighted the presence of different species and serogroups of Legionella in 31 (21.2%) of the 145 wells that were shown to be suitable for irrigation use.A greater number of wells returned positive results for Legionella in summer than in winter (p = 0.023), and the median concentrations were mostly higher in summer (500 CFU/L) than in winter (300 CFU/L). The median temperature in the Legionella positive well waters was significantly higher than that in the negative ones, both in winter and in summer (p < 0.001).Using molecular techniques, Legionella non-pneumophila was found in 37 of the 114 wells earlier detected as suitable for irrigation use but negative for Legionella by the culture-based methods. The distribution of Legionella differ significantly in porous aquifers compared to the karst-fissured ones both with quantitative polymerase chain reaction (qPCR) (p = 0.0004) and viable cells by propidium monoazide (PMA-qPCR) (p = 0.0000). Legionella concentrations were weakly correlated with temperature of water both with qPCR (ρ = 0.47, p = 0.0033) and PMA-qPCR (ρ = 0.41, p = 0.0126).Our data suggest that water that aerosolizes when sprinkled on plants represents a potential source of Legionellosis, with a higher risk from exposure in summer. On a practical level, this finding is important for workers (farmers and gardeners) who are in contact with waters used for irrigation.

Distribution of Legionella and bacterial community composition among regionally diverse US cooling towers.

Cooling towers (CTs) are a leading source of outbreaks of Legionnaires’ disease (LD), a severe form of pneumonia caused by inhalation of aerosols containing Legionella bacteria. Accordingly, proper maintenance of CTs is vital for the prevention of LD. The aim of this study was to determine the distribution of Legionella in a subset of regionally diverse US CTs and characterize the associated microbial communities. Between July and September of 2016, we obtained aliquots from water samples collected for routine Legionella testing from 196 CTs located in eight of the nine continental US climate regions. After screening for Legionella by PCR, positive samples were cultured and the resulting Legionella isolates were further characterized. Overall, 84% (164) were PCR-positive, including samples from every region studied. Of the PCR-positive samples, Legionella spp were isolated from 47% (78), L. pneumophila was isolated from 32% (53), and L. pneumophila serogroup 1 (Lp1) was isolated from 24% (40). Overall, 144 unique Legionella isolates were identified; 53% (76) of these were Legionella pneumophila. Of the 76 L. pneumophila isolates, 51% (39) were Lp1. Legionella were isolated from CTs in seven of the eight US regions examined. 16S rRNA amplicon sequencing was used to compare the bacterial communities of CT waters with and without detectable Legionella as well as the microbiomes of waters from different climate regions. Interestingly, the microbial communities were homogenous across climate regions. When a subset of seven CTs sampled in April and July were compared, there was no association with changes in corresponding CT microbiomes over time in the samples that became culture-positive for Legionella. Legionella species and Lp1 were detected frequently among the samples examined in this first large-scale study of Legionella in US CTs. Our findings highlight that, under the right conditions, there is the potential for CT-related LD outbreaks to occur throughout the US.

Serological and molecular identification of Legionella spp. isolated from water and surrounding air samples in Italian healthcare facilities

BackgroundLegionella is an intracellular microorganism living in natural and artificial aquatic environments. Although its transmission to humans is linked to the inhalation of contaminated aerosols, there is no validated air sampling method for the control and prevention of the disease. The aim of the present study was to provide more information on the distribution of Legionella spp. in indoor environments and to determine whether the same Legionella strains are isolated from air and water samples. MethodsTen healthcare facilities located in seven regions of Italy were enrolled. The serological typing of Legionella spp. from water samples and the surrounding air by active and passive sampling was assessed using polyvalent and monovalent antisera. Subsequently, the strains identified as Legionella pneumophila (Lpn) underwent molecular typing by sequence-based typing (SBT) using seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA). The allelic profile number was assigned using the European Working Group for Legionella Infections–SBT database. ResultsLpn serogroup 6 was the most prevalent serogroup; it was found simultaneously in the air and water samples of three different healthcare facilities. In the remaining seven hospitals, Lpn serogroups 1, 6, 7, 9, and 12 were isolated exclusively from water samples. The molecular investigation showed that Lpn strains in the water and air samples of each positive healthcare facility had the same allelic profile. Strains, identified as sequence types (STs) 728 and ST 1638+ST 1324, were isolated in two respective healthcare facilities, and a new strain, identified as ST 1989, was obtained in one healthcare facility. ConclusionThe application of the SBT method allowed to verify the homology among Legionella strains from water samples and the surrounding air. The results showed that the same Lpn strains were present in the air and water samples, and a new Legionella strain was identified.

Environmental relevance of cooling towers - a systematic review of legionellosis outbreaks

Background Bioaerosols from cooling towers are often suspected to cause community-acquired legionellosis outbreaks. Uncertainty exists about the release and distribution of Legionella into the air, the occurrence of the respirable virulent form and the level of the infective dose. Aims We aimed to evaluate studies on Legionella outbreaks attributed to cooling towers. A systematic review, including data on morbidity and mortality, risk groups, diagnostic tools, meteorological conditions, maintenance actions, and comparative analysis of clinical and environmental isolates, was performed. Methods The literature search was conducted in Medline including publications from January 2001 to August 2012. Relevant findings were synthesized in form of a narrative summary. Results 19 outbreaks were identified affecting 12 countries. Recurring events were observed in Spain and Great Britain, 1609 confirmed cases of legionellosis and 102 cases of death (case-fatality rate 0-29%). Median time between onset of symptoms of first and last case was 36.5 days. The most frequent risk factors were smoking and underlying diseases in about half of the studies. The meteorological conditions varied strongly. Several studies reported a temporal association of outbreaks with technical interventions. A match of clinical and environmental isolates by serotyping and/or molecular subtyping was confirmed in 16 (84%) outbreaks. Conclusion Legionella-contaminated cooling towers as environmental trigger can cause severe health problems and even death of susceptible individuals. Consequently, public health authorities should enforce prevention and rapid risk assessment of outbreaks. Therefore, the registration of cooling towers is important to accelerate source identification and to shorten outbreak duration. To prevent and control Legionella contamination of cooling towers, maintenance actions should aim at low-emission procedures.

Seasonal distribution of Legionella spp. and L. pneumophila in a river in Taiwan evaluated with culture-confirmed and direct DNA extraction methods

Summary In this study, we evaluated the presence and amount of Legionella in along a river in Taiwan, and the relations between seasonal distribution of Legionella spp. and geographic characteristics in the watershed were also evaluated. Water samples were pre-treated and analyzed with culture-confirmed and direct DNA extraction methods. For culture-confirmed method, water samples were cultivated through a series of selective media, and candidate colonies were confirmed by PCR. For direct DNA extraction method, direct DNA extraction was performed from pre-treated water samples. The DNA extracts were analyzed with PCR and DNA sequence analysis for species determination, quantitative PCR (qPCR) was performed to quantify Legionella concentration in the water sample. In all, 150 water samples were included in this study, with 73 (48.6%) water samples detected with Legionella spp., and 17 with L. pneumophila . Over 80% Legionella spp. detections were through direct DNA extraction method, but more than 80% L. pneumophila detections were through culture-confirmed method. While detection of Legionella spp. was done with two methods, positive results were found through only one method. Legionella spp. was detected in all seasons with detection rate ranging between 34.3–58.8% and seasonal average concentration from 1.9 × 10 2 to 7.1 × 10 3 CFU/L. Most of the L. pneumophila detections were from samples collected in fall (38.2%) and summer (6.0%), which also coincided with increased cases of Legionellosis reported through Center of Disease Control in Taiwan. The high prevalence and concentration of Legionella spp. and L. pneumophila in the surface waters should be further evaluated for potential health risks.

An unprecedented outbreak investigation for nosocomial and community-acquired legionellosis in Hong Kong.

The environmental sources associated with community-acquired or nosocomial legionellosis were not always detectable in the mainland of China and Hong Kong, China. The objective of this study was to illustrate the control measures implemented for nosocomial and community outbreaks of legionellosis, and to understand the environmental distribution of legionella in the water system in Hong Kong, China. We investigated the environmental sources of two cases of legionellosis acquired in the hospital and the community by extensive outbreak investigation and sampling of the potable water system using culture and genetic testing at the respective premises. The diagnosis of nosocomial legionellosis was suspected in a patient presenting with nosocomial pneumonia not responsive to multiple beta-lactam antibiotics with subsequent confirmation by Legionella pneumophila serogroup 1 antigenuria. High counts of Legionella pneumophila were detected in the potable water supply of the 70-year-old hospital building. Another patient on continuous ambulatory peritoneal dialysis presenting with acute community-acquired pneumonia and severe diarrhoea was positive for Legionella pneumophila serogroup 1 by polymerase chain reaction (PCR) testing on both sputum and nasopharyngeal aspirate despite negative antigenuria. Paradoxically the source of the second case was traced to the water system of a newly commissioned office building complex. No further cases were detected after shock hyperchlorination with or without superheating of the water systems. Subsequent legionella counts were drastically reduced. Point-of-care infection control by off-boiled or sterile water for mouth care and installation of water filter for showers in the hospital wards for immunocompromised patients was instituted. Territory wide investigation of the community potable water supply showed that 22.1% of the household water supply was positive at a mean legionella count of 108.56 CFU/ml (range 0.10 to 639.30 CFU/ml). Potable water systems are open systems which are inevitably colonized by bacterial biofilms containing Legionella species. High bacterial counts related to human cases may occur with stagnation of flow in both old or newly commissioned buildings. Vigilance against legionellosis is important in healthcare settings with dense population of highly susceptible hosts.

Water quality parameters associated with prevalence of Legionella in hot spring facility water bodies

Some species of Legionella are recognized as opportunistic potential human pathogens, such as Legionella pneumophila, which causes legionnaires disease. Indeed, outbreaks of legionellosis are frequently reported in areas in which the organism has been spread via aerosols from contaminated institutional water systems. Contamination in hot tubs, spas and public baths are also possible. As a result, in this study, we investigated the distribution of Legionella at six hot spring recreation areas throughout Taiwan. Legionella were detected in all six hot spring recreation areas, as well as in 20 of the 72 samples that were collected (27.8%). Seven species of Legionella identified from samples by the direct DNA extraction method were unidentified Legionella spp., Legionella anisa, L. pneumophila, Legionella erythra, Legionella lytica, Legionella gresilensis and Legionella rubrilucen. Three species of Legionella identified in the samples using the culture method were L. pneumophila, unidentified Legionella spp. and L. erythra. Legionella species were found in water with temperatures ranging from 22.7 °C to 48.6 °C. The optimal pH appeared to range from 5.0 to 8.0. Taken together, the results of this survey confirmed the ubiquity of Legionella in Taiwan spring recreational areas. Therefore, a long-term investigation of the health of workers at hot spring recreational areas and the occurrence of Legionella in hot spring recreational areas throughout Taiwan are needed.

Distribution of Legionella and Nontuberculous Mycobacteria in Environment

Distribution of Legionella and Nontuberculous Mycobacteria in Environment

Utilization of polymerase chain reaction and selective media cultivation to identify Legionella in Taiwan spring water samples

In this study, we investigated the distribution of Legionella in sources of spring water and wastewater throughout Taiwan. Legionella were detected with culture method and PCR method from water samples, combined with molecular methods that allow the taxonomic identification of Legionella species. Factors associated with the distribution of Legionella including the physical-chemical and microbiological water quality characteristics were also measured. Legionella were detected in 18 of the 68 samples. Additionally, 16 of the 68 samples analyzed by polymerase chain reaction (PCR) and eight of the 68 samples evaluated using the culture method were found to be positive for Legionella. The Legionella species identified included Legionella pneumophila, unnamed Legionella genotypes, uncultured Legionella spp., and Legionella lytica. Legionella species were found in water with temperatures ranging from 10.0 to 50.6°C and with pH values ranging from 5.59 to 9.32. Significant differences (Mann-Whitney U test, P<0.05) were observed in the presence/absence of Legionella in samples with different pH values when Legionella were detected by the culture method. The results of this survey confirmed that Legionella is ubiquitous in the water of spring recreational areas in Taiwan. Long-term investigations of the occurrence of Legionella in hot spring recreational areas throughout Taiwan are needed.

Legionella prevalence in wastewater treatment plants of Taiwan

Legionella is a bacterium that is ubiquitous in natural and artificial aquatic environments. Some species of Legionella are recognized as opportunistic potential human pathogens. We investigated the distribution of Legionella at seventeen WWTPs throughout Taiwan. Legionella were detected in 10 of the 17 WWTPs (58.8%) and 25 of 41 samples (61.0%). In the integrated, hospital, industrial and domestic wastewater systems were 13/18 (72.2%), 7/12 (58.3%), 2/7 (28.6%) and 3/4 (75.0%) of the samples were positive for Legionella, respectively. The most frequently encountered species were L. donaldsonii and uncultured L. spp., which were both found in 10 samples (24.4% of all samples), then followed by L. lytica (4.9%) and L. pneumophila (4.9%). L. anisa was detected in one sample (2.4%). The results of this survey confirm that Legionella are ubiquitous in WWTPs in Taiwan. Therefore, long-term investigations should be conducted to evaluate the overall occurrence of Legionella in WWTPs in Taiwan.

Legionella prevalence in hot spring recreation areas of Taiwan

Legionella is a bacterium ubiquitous to aquatic environments. Within the genus a few species are recognized as opportunistic potential human pathogens, especially the species Legionella pneumophila, which causes pneumonia legionellosis. Outbreaks of legionellosis are frequently reported by hotel guests and hospital patients, and are spread through inhaled aerosols of contaminated institutional water systems. Contaminations in hot tubs, spas and public baths are also possible. As a result, in this study, we investigated the distribution of Legionella at seven hot spring recreational areas throughout Taiwan. We gathered data on factors potentially associated with the pathogen's distribution, including environment, facility operation, and physical and microbiological water quality parameters. Spring water was collected from 91 sites and Legionella was detected in 21 (23%). The most frequently detected was L. pneumophila, followed by uncultured Legionella species, Legionella-like amoebal pathogen. Five species, L. bozemanii, L. dumoffi, L. feelei, L. lyticum and L. oakridgenesis, were all detected once. Legionella species were found in water temperatures ranging from 22 to 50 °C. Optimal pH appeared to be between 5.0 and 9.0. The prevalence of Legionella also coincided with the prevalence of indicator microorganisms. Legionella detection was not proportional to the frequency of cleaning. Results of this survey confirm the ubiquity of Legionella in Taiwan spring recreation areas. L. pneumophila, the organism responsible for the majority of legionellosis outbreaks, should be considered a potential public health threat in spa areas of Taiwan.

Distribution of Legionella spp. in hydrothermal areas in continental Portugal and the island of São Miguel, Azores

Nineteen aquatic environment sites from three hydrothermal areas on continental Portugal and one area on the island of São Miguel, Azores, were examined for the recovery of Legionella spp. Physicochemical and bacteriological parameters were also determined for each site. Water temperatures varied between 22 and 67.5 degrees C, although the majority had temperatures above 40 degrees C; the pH varied between 5.5 and 9.2. The number of Legionella spp. recovered varied between 5.0 x 10(2) and 2.3 x 10(6) CFU/liter. A total of 288 isolates from 14 sites were identified by indirect immunofluorescence assay. The majority of the isolates belonged to Legionella pneumophila (74.3%), of which most belong to serogroup 1, but the relative proportion of L. pneumophila serogroups varied considerably. L. pneumophila serogroup 1 constituted 96.2% of the isolates in area 2 from central Portugal, but no isolates of this serogroup were recovered from São Miguel, where serogroup 6 strains were the predominant isolates. Ninety-six percent of the L. pneumophila serogroup 1 isolates belonged to monoclonal antibody subgroups OLDA and Bellingham. Other species identified were L. bozemanii serogroup 2, L. dumoffii, L. micdadei, L. moravica, L. oakridgensis, L. sainticrucis, and L. sainthelensi. Two undescribed species, which react by indirect immunofluorescence assay to antisera to "L. londoniensis" and "L. nautarum" and a group of isolates with strong cross-reaction to L. cincinnatiensis/L. sainticrucis/L. longbeachae by indirect immunofluorescence assay were also recovered. The latter were the only isolates recovered from area 3, in east central Portugal, over a period of 1 year.