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Given the recent global surge in Legionnaires' disease cases, the monitoring of Legionella pneumophila becomes increasingly crucial. Epidemiological cases often stem from local outbreaks rather than widespread dissemination, emphasizing the need to study the characteristics of this pathogen at a local level. This study focuses on isolates of L. pneumophila in the Italian region of Friuli Venezia Giulia to assess specific genotype and phenotype distribution over time and space. To this end, a total of 127 L. pneumophila strains isolated between 2005 and 2017 within national surveillance programs were analysed. Rep-PCR, RAPD, and Sau-PCR were used for genotypic characterization, while phenotypic characterization was conducted through fatty acids analysis. RAPD and Sau-PCR effectively assessed genetic characteristics, identifying different profiles for the isolates and excluding the presence of clones. Although Sau-PCR is rarely used to analyse this pathogen, it emerged as the most discriminatory technique. Phenotypically, hierarchical cluster analysis categorized strains into three groups based on varying membrane fatty acid percentages. However, both phenotypic and genotypic analyses revealed a ubiquitous profile distribution at a regional level. These results suggest an absence of correlations between strain profiles, geographical location, and isolation time, indicating instead high variability and strain dissemination within this region., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Colautti et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Legionnaires' disease is caused by inhalation or aspiration of small water droplets contaminated with Legionella, commonly found in natural and man-made water systems and in moist soil. Over the past 5 years, notification rates of this disease have almost doubled in the European Union (EU) / European Environmental Agency (EEA), from 1.4 in 2015 to 2.2 cases per 100,000 population in 2019. Some studies show that the greater presence of the microorganism in the water network and the increase in cases of legionellosis could be related to the variations in some environmental factors, such as air temperature, which may influence the water temperature., Study Design: Climate change is currently a prominent topic worldwide because of its significant impact on the natural environment. It is responsible for the increase in numerous waterborne pathologies. The purpose of this study was to correlate the air temperature recorded in Apulia region from January 2018 to April 2023 with the presence of Legionella in the water networks of public and private facilities and the incidence rates of legionellosis during the same period., Methods: During the period from January 2018 to April 2023, water samples were collected from facilities involved in legionellosis cases and analyzed for Legionella. During the same period, all the cases notified to the regional epidemiological observatory (OER-Apulia) were included in this study. Statistical analyses were conducted using the Shapiro-Wilk test to determine whether the Legionella load was distributed normally, the Wilcoxon rank sum test to compare the air temperatures (average and range) of the negative and positive samples for Legionella detection, and the multivariate analysis (Poisson regression) to compare the Legionella load with the water sample temperature, average air temperature, and temperature range on the day of sampling. The Wilcoxon test for paired samples was used to compare legionellosis cases between the warmer and colder months., Results: Overall, 13,044 water samples were analyzed for Legionella and 460 cases of legionellosis were notified. Legionella was isolated in 20.1% of the samples examined. The difference in the air temperature between negative samples and positive samples was statistically significant (p-value < 0.0001): on days when water samples tested positive for Legionella a higher temperature range was observed than on days when water samples tested negative (p-value = 0.004). Poisson regression showed a direct correlation between Legionella load, water temperature, and average air temperature. The incidence of legionellosis cases in warmer months was higher than in colder months (p-value = 0.03)., Conclusions: Our study highlights a significant increase in the load of Legionella in the Apulian water network, and an association between warmer temperatures and legionellosis incidence. In our opinion, further investigations are needed in different contexts and territories to characterize the epidemiology of legionellosis, and to explain its extreme variability in different geographical areas and how these data may be influenced by different risk factors.

Legionnaires' disease (LD) is a severe pneumonia caused by bacteria belonging to the genus Legionella . This is a major public health concern and infections are steadily increasing worldwide. Several sources of infection have been identified, but they have not always been linked to human isolates by molecular match. The well-known Legionella contamination of private homes has rarely been associated with the acquisition of the disease, although some patients never left their homes during the incubation period. This study demonstrated by genomic matching between clinical and environmental Legionella isolates that the source of an LD cluster was a private building. Monoclonal antibodies and sequence-based typing were used to type the isolates, and the results clearly demonstrated the molecular relationship between the strains highlighting the risk of contracting LD at home. To contain this risk, the new European directive on the quality of water intended for human consumption has introduced for the first time Legionella as a microbiological parameter to be investigated in domestic water systems. This should lead to a greater attention to prevention and control measures for domestic Legionella contamination and, consequently, to a possible reduction in community acquired LD cases.

In September 2018 in Brescia province, northern Italy, an outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 2 ( Lp2 ) occurred. The 33 cases (two fatal) resided in seven municipalities along the Chiese river. All cases were negative by urinary antigen test (UAT) and most were diagnosed by real-time PCR and serology. In only three cases, respiratory sample cultures were positive, and Lp2 was identified and typed as sequence type (ST)1455. In another three cases, nested sequence-based typing was directly applied to respiratory samples, which provided allelic profiles highly similar to ST1455. An environmental investigation was undertaken immediately and water samples were collected from private homes, municipal water systems, cooling towers and the river. Overall, 533 environmental water samples were analysed and 34 were positive for Lp . Of these, only three samples, all collected from the Chiese river, were Lp2 ST1455. If and how the river water could have been aerosolised causing the LD cases remains unexplained. This outbreak, the first to our knowledge caused by Lp2 , highlights the limits of UAT for LD diagnosis, underlining the importance of adopting multiple tests to ensure that serogroups other than serogroup 1, as well as other Legionella species, are identified.

In July 2018, a large outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 1 (Lp1) occurred in Bresso, Italy. Fifty-two cases were diagnosed, including five deaths. We performed an epidemiological investigation and prepared a map of the places cases visited during the incubation period. All sites identified as potential sources were investigated and sampled. Association between heavy rainfall and LD cases was evaluated in a case-crossover study. We also performed a case-control study and an aerosol dispersion investigation model. Lp1 was isolated from 22 of 598 analysed water samples; four clinical isolates were typed using monoclonal antibodies and sequence-based typing. Four Lp1 human strains were ST23, of which two were Philadelphia and two were France-Allentown subgroup. Lp1 ST23 France-Allentown was isolated only from a public fountain. In the case-crossover study, extreme precipitation 5-6 days before symptom onset was associated with increased LD risk. The aerosol dispersion model showed that the fountain matched the case distribution best. The case-control study demonstrated a significant eightfold increase in risk for cases residing near the public fountain. The three studies and the matching of clinical and environmental Lp1 strains identified the fountain as the source responsible for the epidemic.

Background: Legionella pneumophila (Lp) is the most common etiologic agent causing Legionnaires' Disease (LD). Water systems offer the best growth conditions for Lp and support its spread by producing aerosols. From 2015 to 2017, the Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis of Palermo monitored the presence of Lp in nine prisons in Western Sicily. During this investigation, we compared Lp isolates from environmental samples in a prison located in Palermo with isolates from two prisoners in the same prison., Methods: We collected 93 water samples from nine Sicilian prisons and the bronchoalveolar lavages (BALs) of two prisoners considered cases of LD. These samples were processed following the procedures described in the Italian Guidelines for the Prevention and Control of Legionellosis of 2015. Then, genotyping was performed on 19 Lp colonies (17 from water samples and 2 from clinical samples) using the Sequence-Based Typing (SBT) method, according to European Study Group for Legionella Infections (ESGLI) protocols., Results: Lp serogroup (sg) 6 was the most prevalent serogroup isolated from the prisons analyzed (40%), followed by Lp sg 1 (16%). Most of all, in four penitentiary institutions, we detected a high concentration of Lp >10 4 Colony Forming Unit/Liter (CFU/L). The environmental molecular investigation found the following Sequence Types (STs) in Lp sg 6: ST 93, ST 292, ST 461, ST 728, ST 1317 and ST 1362, while most of the isolates in sg 1 belonged to ST 1. We also found a new ST that has since been assigned the number 2451 in the ESGLI-SBT database. From the several Lp sg 1 colonies isolated from the two BALs, we identified ST 2451., Conclusions: In this article, we described the results obtained from environmental and epidemiological investigations of Lp isolated from prisons in Western Sicily. Furthermore, we reported the first cluster of Legionnaires' in an Italian prison and the molecular typing of Lp sg 1 from one prison's water system and two BALs, identified the source of the contamination, and discovered a new ST.

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.

An unusually long-lasting community-acquired outbreak of Legionnaires' disease (LD) occurred in the inhabitants of a town in northern Italy from 2005 to 2008. Overall, 43 cases were diagnosed including five deaths. Hundreds of water samples were collected for Legionella isolation but only two clinical samples were obtained. Clinical strains were ST23 as were environmental isolates detected in most Legionella-positive patients' homes and those from a public fountain. Although no Legionella was found in the municipal water mains, a continuous chlorination was applied in 2008. This action resulted in a halving of cases, although incidence remained tenfold higher than the Italian average incidence until the end of 2013, when it dropped to the expected rate. Retrospective analyses of prevalent wind direction suggested that a hidden cooling tower could have been the main cause of this uncommon outbreak, highlighting the importance of implementation of cooling tower registers in supporting LD investigations.

Introduction: Legionnaires' disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large buildings, such as hospitals, are often contaminated with legionellae and therefore represent a potential risk for the hospital population. The aim of this study was to evaluate the potential contamination of Legionella pneumophila (LP) in a large hospital in Italy through georeferential statistical analysis to assess the possible sources of dispersion and, consequently, the risk of exposure for both health care staff and patients., Materials and Method: LP serogroups 1 and 2-14 distribution was considered in the wards housed on two consecutive floors of the hospital building. On the basis of information provided by 53 bacteriological analysis, a 'random' grid of points was chosen and spatial geostatistics or FAIk Kriging was applied and compared with the results of classical statistical analysis., Results: Over 50% of the examined samples were positive for Legionella pneumophila. LP 1 was isolated in 69% of samples from the ground floor and in 60% of sample from the first floor; LP 2-14 in 36% of sample from the ground floor and 24% from the first. The iso-estimation maps show clearly the most contaminated pipe and the difference in the diffusion of the different L. pneumophila serogroups., Conclusion: Experimental work has demonstrated that geostatistical methods applied to the microbiological analysis of water matrices allows a better modeling of the phenomenon under study, a greater potential for risk management and a greater choice of methods of prevention and environmental recovery to be put in place with respect to the classical statistical analysis.

Molecular typing methods for discriminating different bacterial isolates are essential epidemiological tools in prevention and control of Legionella infections and outbreaks. A selection of 56 out of 184 Legionella pneumophila serogroup 1 (Lp1) clinical isolates, collected from different Italian regions between 1987 and 2012, and stored at the National Reference Laboratory for Legionella, were typed by monoclonal antibody (MAb) subgrouping, amplified fragment length polymorphism (AFLP) and sequence based typing (SBT). These strains were isolated from 39 community (69.6%), 14 nosocomial (25%) and 3 travel associated (5.4%) Legionnaires'disease cases. MAb typing results showed a prevalence of MAb 3/1 positive isolates (75%) with the Philadelphia subgroup representing 35.7%, followed by Knoxville (23.2%), Benidorm (12.5%), Allentown/France (1.8%), Allentown/France-Philadelphia (1.8%). The remaining 25% were MAb 3/1 negative, namely 11 Olda (19.6%), 2 Oxford (3.6%) and 1 Bellingham (1.8%) subgroups. AFLP analysis detected 20 different genomic profiles. SBT analysis revealed 32 different sequence types (STs) with high diversity of STs (IODSTs=0.952) 12 of which were never described before. ST1 and ST23 were most frequently isolated as observed worldwide. A helpful analysis of data from SBT, MAb subgrouping and AFLP is provided, as well as a comparison to the Lp1 types investigated from other countries. This study describes the first Italian Lp1 strains database, providing molecular epidemiology data useful for future epidemiological investigations, especially of travel associated Legionnaires' diseases (TALD) cases, Italy being the country associated with the highest number of clusters., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Objective: The present report aims to molecularly characterize seven clinical L. pneumophila (L. pn.) sg 1 isolated from nosocomial acquired infections in Apulia region, using the European Working Group on Legionella Infections (EWGLI), sequence-based typing (SBT) and amplified fragment length polymorphism (AFLP) protocols and to compare the identified sequence types (STs) with those available in the EWGLI database., Methods: In the period, January 2000-December 2012, 151 is cases (136 of community and 15 of nosocomial origin) of Legionnaires' disease were notified to the Regional Center for Epidemiology. With regard to nosocomial cases, 8 were confirmed by the isolation of Legionella spp. from respiratory secretions. These clinical isolates were characterized by amplified fragment length polymorphism (AFLP) and sequence-based typing (SBT), using the EWGLI standardized protocol., Results: The clinical isolates belong to ST42, ST23 and ST1. The AFLP confirms the SBT results. Comparing the STs herein detected with those already in the EWGLI SBT database, the 3 STs are frequent in other European countries., Conclusions: The molecular analysis demonstrates that the 3 STs are the most frequent in Italy and in Europe, supporting the hypothesis that some specific L. pn. sg 1 clones have gained widespread dissemination probably due to a common ecological niche. Further researches are required to investigate the potential changing incidence of STs and the fitness of emerging strains or clonal groups in environmental strains.

According to the Italian Surveillance System for Legionnaires' disease (LD), physicians must fill in a form for every case and send it through the Local Health Units to the National Institute of Health (Istituto Superiore di Sanità, ISS). Forms reported in the period from 2000 to 2011 were analysed and discussed. A total of 9,803 cases of LD were reported to ISS during the study period. The median age of cases was 63 years, with a ratio male/female of 2.6 and a case fatality rate of 11.8%. The number of cases has been steadily increasing from 192 cases in 2000 to 1,235 in 2010 and 1,008 cases in 2011. The reported cases showed a geographical gradient, with the highest number notified in the north and the lowest in the south. The majority of cases (73.0%) were community-acquired, followed by travel-associated (13.5%) and healthcare-associated cases (9.3%), cases acquired in long-term care facilities (2.1%), and other types of exposure (2.1%). Even though the increasing trend of LD in Italy indicates an improvement in the ability to detect and report cases, the geographical gradient highlights the existence of low reporting areas where the epidemiological surveillance of LD should be further strengthened.

Introduction: Legionella bacterium manifests itself in Legionnaire's disease and Pontiac fever, it is mainly found and transmitted by aerosol produced in cooling towers, water distribution plants and medical equipment, and it affects mainly elder persons in poor health., Methods: The population of Venice Local Health Unit was divided in two areas of study and the incidence of legionellosis in residents of Venice historical centre (Distretto Sanitario 1) and in residents of the mainland and coastal areas (Distretti Sanitari 2, 3, 4) was calculated. The cases were those notified to the Public Health Unit by law, and the population of residents was that of the eligible for health care in the archives of the Local Health Unit. Only cases of legionellosis in residents who had not travelled in the 10 days previous of the onset of disease, and not related to nosocomial clusters were considered. The standardized incidence ratio was then calculated and confidence interval were defined by Poisson distribution., Results: Given the population of the two areas, 59801 in Distretto Sanitario 1 and 237555 in Distretti 2, 3, 4, the raw incidence of disease is respectively 87 per 100000 and 20 per 100000 in time 2002-2010. The standardized incidence ratio for the population of Distretto Sanitario 1 vs the remaining population is 4.3., Discussion: The difference in risk of getting the disease in this two residential areas geographically very close, is probably related to the different buildings' characteristics, old and difficult to maintain in Venice historical centre.

Since 18 August 2011, 17 cases of travel-associated Legionnaires' disease have been reported. They were tourists from five European countries who had stayed in five accommodation sites in Lazise, Italy. The dates of symptom onset ranged from 18 July to 25 August 2011. Control measures were implemented and no further cases associated with stays at the sites have been reported after disinfection. Timely notification of any further cases potentially associated with stay in Lazise is recommended.

Background: Telephone manholes (TMs) are underground wells, used in Italy by the telecommunication companies to locate telephone networks. Following a fatal case of Legionnaires' disease (LD), acquired during working activity in a TM, we investigated whether Legionella was present in TMs and could be a risk for manhole workers (MWs)., Methods: Three hundred fifty-three environmental samples were collected from 100 TMs, and serum antibody titer against Legionella pneumophila and Legionella species non-pneumophila was determined from both MWs and control non-manhole workers., Results: L pneumophila and Legionella species non-pneumophila were detected in 28% of water samples, in 8% of the biofilm, and in 6% of sediment matrices taken in TMs, in a concentration range of 10(2) to 10(4) colony-forming units/L. No Legionella was found in TM air samples. Although there was a statistically significant difference (P = .027) in antibody titer to L pneumophila serogroup 1 (Lp1) between MWs and non-manhole workers, a multivariate logistic regression analysis showed a significant association between antibody against Lp1 and both age group and the practice of aquatic sports., Conclusion: Although further investigations will be performed to quantify the risk of acquiring legionellosis, this preliminary study demonstrates for the first time the presence of Legionella, including human pathogenic species, in a working environment such as TM.

Various techniques have been developed in recent years for the molecular typing of microorganisms. Remains particularly difficult to isolate clinical strains for the low availability of cases and even more problematic matching clinical / environmental strains. We investigated 13 strains of Legionella pneumophila of clinical and environmental origin, isolated in 3 Health Facilities in Milan (2003-2006), using three molecular typing methods: Pulse-Field Gel Electrophoresis, Amplified Fragment Length Polymorphism and Sequence-Based Typing. PFGE and AFLP showed the correlation between a clinical case with only one of the environmental isolates taken from the places frequented by the patient, demonstrating with certainty the nosocomial origin of the case and identifying the source of infection in the shower water (Clin. 1 and Env. 1N). Two clinical samples from patients admitted to different wards presented an identical profile, which suggests that the nosocomial origin assumed an epidemic form, even without having isolated the environmental strain due to the absence of samples drawn during the period under consideration (Clin. 2 and 3). Finally, the comparison between the isolated environmental strains demonstrated a heterogeneous presence of strains, not correlated to each other although they belong to the same serum-group, having profiles that are clearly different regarding number and position of bands (Env. 2 and 4). The profile 2,10,18,10,1,1 had never been isolated and typed previously in Europe. The SBT has proved a better technique for reproducibility and interpretation of results than PFGE and AFLP To complete studies on SBT method, now considered gold standard, is currently being the EWGLI 5th Proficiency Panel, in which we are actively involved with the genotyping of five strains according to the latest version of the protocol (4.1).

It has been analyzed 36 samples of water proceeding from beach shower facilities: 7 of these were found to be contaminated with Legionella (19.44%). In three showers, L. pneumophila 1 was reported, in two L. pneumophila 2-14; in another two cases L. pneumophila 2-14 was found together with Legionella sp. and L. pneumoplhila 1 together with L. pneumophila 2-14. This study, which confirms the circulation of Legionella in our region of southern Italy, extends the list of the possible sources of infection, including also public and private beaches among the contaminated sites. It is the Authors opinion that when evaluating the risk in these cases we should take into account that the crowding of the beaches in the summer months and the communal nature of shower use in these periods increases the frequency of exposure of children and old people. These vulnerable categories are significantly more likely to develop the disease once infected.

For several years, over 50% of the cases of travel-associated Legionnaires' disease (TALD) reported to the European Working Group for Legionella Infections (EWGLINET) have been among travellers to France, Italy, and Spain. We describe clusters of TALD cases reported in these countries during a four-year period. We analysed data from EWGLINET and from the individual countries. In all three countries, upon notification of a cluster, local health authorities are alerted by the national collaborator and immediately begin an environmental investigation at the accommodation site, which includes risk assessments and analysis of water samples. From July 1, 2002 to June 30, 2006, 2,101 accommodation sites were associated with TALD cases and reported by EWGLINET to Italian, Spanish and French collaborators. Of these, 252 sites (12%) were associated with clusters: 13.8% (96/697) in Italy, 13.2% (81/615) in Spain and 9.5% (75/789) in France. Overall, 641 cases were reported. Hotels, camping sites and ships and other sites represented respectively 83%, 10% and 7% of the total accommodation sites, with similar proportions in the three countries. In 99% of the sites, samples were collected; 62% of them were found to be positive for Legionella. The findings of this study highlight that disinfection and long-term preventive measures were correctly implemented by the large majority of sites. However, additional efforts must be made to further reduce the percentage of re-offending sites so as to reduce the number of accommodations that are contaminated by Legionella.

A prospective surveillance study of legionnaires disease and an environmental survey of Legionella species were performed simultaneously in a general hospital. During a period of 3 years, 705 patients with pneumonia were screened with a Legionella urinary antigen test, and pneumonia was confirmed by culture and serological tests. Twelve cases of legionnaires disease were identified, none of which were hospital acquired, despite the fact that 60% of hospital water samples were contaminated with Legionella pneumophila at a concentration of more than 10(3) colony-forming units/L. The probable source of infection was identified for only 2 community-acquired cases. The results show that environmental contamination alone is not able to predict the risk of legionnaires disease. If no cases are present, monitoring of hospital water systems is of little significance; clinical surveillance is much more important.

The objective of this study was to evaluate the degree of underreporting to the Italian National Legionellosis Register (NLR). For the year 2002, all cases of Legionellosis notified to the NLR were compared with cases recorded in the hospital discharge record (HDR) database. The number of unreported cases and the total number of cases in the population were estimated using the capture-recapture method with two independent data sources. Seventeen out of 21 Italian regions participated in the study. Overall, underreporting was estimated to be 21.4% and was found to be significantly greater in the Centre-South (28.2%) than in the North (20.0%). However, even after taking into account the higher degree of underreporting, a significantly lower incidence of the disease is registered in central-southern Italy. The hypothesis, which needs to be verified, is that, in addition to underreporting, under-diagnosis of legionellosis is more widespread in this geographical area.

In an university hospital of about 900 beds, a clinical surveillance was activated to detect cases of Legionnaires' disease in patients affected by community and/or nosocomial-acquired pneumonia. In the hospital Legionella spp was detected in the hot water distribution system and various disinfecting and control procedures were adopted to reduce contamination. Contemporary, the clinical surveillance began with the systematic detection of Legionella urinary antigen among recovered pneumonia, seroconversion as confirmation test and the collection of respiratory secretions or other biological materials to isolate the microorganism in patients positive to the urinary antigen. From September 2003 to May 2005, 486 pneumonia were followed, 98 of which considered of nosocomial origin. In total, 15 cases of community-acquired Legionnaires' disease were detected by the urinary test, whereas no cases of nosocomial origin were found. The characteristics of the detected cases are described in comparison with the other pneumonia and the surveillance cost was evaluated. The systematic clinical surveillance for Legionella infections is feasible with limit costs, allows to detect community-acquired cases otherwise unknown and to ascertain the absence/presence of nosocomial-acquired pneumonia, irrespective of the environment contamination.

The author goes over the steps that have marked the individuation and knowledge of Legionellosis, from the point of view of Public Health. She stresses the importance of surveillance and discusses the disease precautionary measures and sanitary control.

Much data has been gathered by the EWGLINET scheme on the distribution of cases of travel-associated Legionnaires' disease (TALD) by country of infection, but less analysis has been carried out on the distribution of these cases within countries. Travel-associated cases with onset in 2002 linked to France, Italy, Spain and Turkey were mapped. Rates of Legionnaires' disease per 100,000 tourists were calculated for internal and foreign visitors for the regions of each country, and mapped. Rates of 1.5 cases/100,000 and 2 cases/100,000 tourists were classified as 'high' and 'very high' respectively. Cases of TALD were concentrated in certain regions, but when rates were calculated using tourist data, the results were relatively constant throughout each country. Rates were higher among foreign visitors than internal visitors; three of the countries had at least one region with 'high' rates, whilst Turkey additionally had three regions with 'very high' rates.

Travel for business or tourism has become increasingly common in the age we live in. The great volume of national and international traffic and the speed of transportation are inevitably linked to a possible increased risk of acquiring certain illnesses such as Legionellosis, which, in fact, has shown a consistently increased incidence in recent years. In this paper, a brief introduction regarding the etiology and clinical and epidemiological characteristics of the disease, is followed by recent national and international data regarding its diffusion and guidelines for its prevention and control.

In the summer of 2003 a community-acquired outbreak of Legionella pneumophila occurred in Rome, Italy. Three molecular typing methods, pulse-field gel electrophoresis, amplified fragment length polymorphism analysis, and sequence-based typing (SBT), were used to establish the clonal correlation among the isolates of the epidemic cluster. By comparison of the methods, SBT was the most rapid and the easiest to perform and provided unambiguous results.

Between August and October 2003, 15 cases of Legionnaires' disease were detected in the 9th district of Rome. To identify possible sources of Legionella exposure, a matched case-control study was conducted and environmental samples were collected. Hospital discharge records were also retrospectively analysed for the period July-November 2003, and results were compared with the same period during the previous 3 years. The case-control study revealed a significantly increased risk of disease among those frequenting a specific department store in the district (OR 9.8, 95% CI 2.1-46.0), and Legionella pneumophila was isolated from the store's cooling tower. Genotypic and phenotypic analysis of human and environmental isolates demonstrated that the cluster was caused by a single strain of L. pneumophila serogroup 1, and that the cooling tower of the store was the source of infection. The increased number of hospital admissions for microbiologically undiagnosed pneumonia during the study period may indicate that some legionellosis cases were not identified.

The frequent occurrence of Legionnaires' disease outbreaks in many countries, including Italy, highlights the importance of epidemiological investigations on this disease. For this purpose, an active surveillance programme of pneumonia patients was carried out in a large hospital in Apulia (Italy) from March 2001 to December 2003. A total of 612 patients were tested for Legionella pneumophila infection by urinary antigen detection and evaluation of antibodies titre. Culture of respiratory specimens was performed on 117 patients. Thirty-seven patients (6%) tested positive for legionellosis: 10 resulted nosocomial cases and 27 as community-acquired. Only 9 cases di Legionella pneumophila infection were reported from Apulia to the routine surveillance system between 1996 and 2000. The results of our study denote the level of underestimation of this disease in Apulia.

The atypical respiratory pathogens Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila are now recognised as a significant cause of acute respiratory-tract infections, implicated in community-acquired pneumonia, acute exacerbations of chronic bronchitis, asthma, and less frequently, upper respiratory-tract infections. Chronic infection with C. pneumoniae is common among patients with chronic obstructive pulmonary disease and may also play a role in the natural history of asthma, including exacerbations. The lack of a gold standard for diagnosis of these pathogens still handicaps the current understanding of their true prevalence and role in the pathogenesis of acute and chronic respiratory infections. While molecular diagnostic techniques, such as polymerase chain reaction, offer improvements in sensitivity, specificity and rapidity over culture and serology, the need remains for a consistent and reproducible diagnostic technique, available to all microbiology laboratories. Current treatment guidelines for community-acquired pneumonia recognise the importance of atypical respiratory pathogens in its aetiology, for which macrolides are considered suitable first-line agents. The value of atypical coverage in antibiotic therapy for acute exacerbations of chronic bronchitis and exacerbations of asthma is less clear, while there is no evidence to suggest that atypical pathogens should be covered in antibiotic treatment of upper respiratory-tract infections.

In Italy, 35 clusters of travel associated Legionnaires' disease were identified from July 2002, when the European Guidelines for Control and Prevention of Travel Associated Legionnaires' Disease have been adopted by the EWGLINET network, to October 2003. Eight per cent (28.6%) would not have been identified without the network. The clusters detected were small, ranging from 2 cases to a maximum of 6. All clusters involved 5 camping sites and 30 hotels/residences, and an overall of 87 patients. The diagnosis was confirmed in 92.0% of the cases and mainly performed by urinary antigen detection (84.7%). A clinical isolate was available only in one case. Following environmental investigations, samples were collected for all the 35 clusters from the water system, and Legionella pneumophila was found in 23 occasions (65.7%). In 15 resorts out of 35, investigations were already in progress at the time of EWGLI cluster notification, since in Italy full environmental investigation is performed even after notification of a single case. Control measures were implemented in all accommodation sites at risk and one hotel only was closed. In all the 35 clusters, reports were completed and sent on time, highlighting that it is possible to comply with the procedures requested by the European Guidelines.

The European Surveillance Scheme for Travel Associated Legionnaires' Disease (EWGLINET) was notified of 360 cases in 2000 and 481 cases in 2001, the highest number reported since 1987. This increase reflects enhanced surveillance activities, especially in the Netherlands, France and Italy, mainly through urinary antigen detection test (78% of cases in 2001). The median delay in reporting to the scheme fell to under 30 days, at the cost of some loss of information on the outcomes of illness. In 2000, 28 clusters were detected compared to 72 in 2001, most of this rise resulting from a change in the definition of clusters. In 2000 and 2001, 55 and 140 environmental investigations were reported respectively.

The hot water supplies of 11 private healthcare facilities in the city of Bologna, Italy, were monitored for the presence of Legionella spp. Four samplings were made in each establishment over a period of one year and in total 121 samples were collected from distribution points situated near the water-boiler and inside the wards (taps and showers). Legionellae were recovered from all the water supplies in question: Legionella spp. in 86.8% of samples, L. pneumophila in 82.6% of samples. L. pneumophila was found in all the water supplies at levels averaging above 10(4)cfu/L in five health facilities and reaching a maximum concentration of 10(7)cfu/L. The only parameter to have affected the presence of legionellae was the water temperature, which was seen to be inversely correlated to the concentration of Legionella spp. Despite the high levels of contamination from L. pneumophila, no cases of nosocomial Legionnaires' disease were reported during the period of the study., (Copyright 2002 The Hospital Infection Society.)

An outbreak of nosocomial legionnaires' disease in a hospital of Northern Italy is described, together with the epidemiological survey and the control measures adopted. Two patients developed Legionella pneumophila (serogroup 1) pneumonia, one (immunodepressed) died. The Task Group organised by the Health Service excluded other previous nosocomial infections, and made controls on patients and personnel of at risk units (all negative). An intensive programme of environmental sampling and educational activities on personnel have been carried out. The environmental surveillance revealed that the centralised hot water distribution system of the hospital was colonised with Legionella. Shock heating and hyperchlorination of water were applied, which reduced the number of contaminated sites short term, but recolonisation took place two months later. We underline the difficulties encountered to control Legionella by active surveillance of water quality; once the system is contamined, Legionella eradication may be difficult and expensive, and cases of hospital-acquired legionnaieres' disease are likely to occur.

The occurrence of legionnaires' disease has been described previously in passengers of cruise ships, but determination of the source has been rare. A 67-year-old, male cigarette smoker with heart disease contracted legionnaires' disease during a cruise in September 1995 and died 9 days after disembarking. Legionella pneumophila serogroup 1 was isolated from the patient's sputum and the ship's water supply. Samples from the air-conditioning system were negative. L. pneumophila serogroup 1 isolates from the water supply matched the patient's isolate, by both monoclonal antibody subtyping and genomic fingerprinting. None of 116 crew members had significant antibody titers to L. pneumophila serogroup 1. One clinically suspected case of legionnaires' disease and one confirmed case were subsequently diagnosed among passengers cruising on the same ship in November 1995 and October 1996, respectively. This is the first documented evidence of the involvement of a water supply system in the transmission of legionella infection on ships. These cases were identified because of the presence of a unique international system of surveillance and collaboration between public health authorities.

Fatty acid profile analysis, monoclonal antibody (MAb) subtyping, pulsed-field gel electrophoresis (PFGE), arbitrarily primed polymerase chain reaction (AP-PCR), and ribotyping were used to compare clinical and environmental Legionella pneumophila serogroup 1 isolates from an outbreak of Legionnaires' disease presumptively associated with cooling towers. According to the Oxford subtyping scheme, the MAb subtype of patients' isolates and of two strains originating from a cooling tower was Pontiac, whereas the other isolates were subtype Olda. The strains showed no intrinsic strain-to-strain difference in fatty acid profiles, and ribotyping and length polymorphism of the 16S-23S rDNA intervening regions failed to reveal any differences between the isolates. Conversely, PFGE and AP-PCR appeared to be more discriminatory, as the same genomic profile was found for the clinical and some environmental strains. Meteorologic and epidemiological data and the results of molecular analysis of the Legionella pneumophila serogroup 1 isolates support the hypothesis that the infection was transmitted from one of the cooling towers to the indoor environment of the same building, to homes in proximity that had open windows, and to the streets. In fact, the outbreak diminished and later ended after a part in the tower was replaced. This investigation demonstrates the utility of combined molecular methods (i.e., phenotypic and genomic typing) in comparing epidemiologically linked clinical and environmental isolates. Finally, the outbreak confirms the risk of Legionnaires' disease posed by cooling towers, mainly when atmospheric thermal and humidity inversions occur. This finding emphasizes the need to determine whether the source of infection is in the living or working environment or somewhere else.

The prevalence of anti-Legionella pneumophila serogroup 1 antibodies in 777 blood donors of the Turin area was determined by the indirect immunofluorescence assay (IFA) and by the microagglutination test (MA). Low titers (IFA of 1/16 and MA of 1/8) were found in 0.3% of the subjects. A statistically significant difference was not observed by sex and by age for IFA titers, but was noted by sex for MA titers of > or = 1/4 (p < 0.05). The upper limit of normal titer was < 1/8 by IFA and < 1/4 by MA at 15% cutoff level and 1/8 by IFA and 1/4 by MA at 1% cutoff level. In conclusion, the prevalence of antibodies in the Turin area was very low; IFA titers of > or = 1/64 and MA titers of > 1/16 can be considered as presumptive of infection in a single serum specimen of a patient with pneumonia; no change in the epidemiology of the disease was observed in the recent years.

We studied 177 patients with pneumonia admitted to an internal medicine department over a period of 3 years to determine the incidence of two emerging pathogens, Legionella pneumophila and Mycoplasma pneumoniae. Clinical, radiological and laboratory tests were performed and included blood cultures, serology, gram staining and sputum cultures. L. pneumophila was the agent involved in 9 patients (5.1%) and M. pneumoniae in 12 (6.8%). These prevalences were about in the middle of the range of previously published figures. Legionella pneumonia is a rare illness, which even in the absence of suggestive clinical signs must be considered because of its possibly serious course and to allow appropriate therapeutic decisions to be made.

A collaborative retrospective study based on serologic diagnosis was conducted to assess the etiological role sustained by privileged pathogens in Italy. The results obtained indicate the Mycoplasma, Chlamydia and Legionella are important etiologic agents of lower respiratory tract infections in Italy since they account for about 31% of the cases taken into consideration in this survey. We found a high incidence of M. pneumoniae (12.3%), C. pneumoniae (10.5%) and L. pneumophila (8.3%). These results are in line with similar figures reported in the recent literature. While the data gathered in our survey do not allow us to clarify the nature of the agents involved in the etiology of the majority (70%) of the respiratory infections occurring in Italy, it seems safe to assume that after Streptococcus pneumoniae and Haemophilus influenzae, the privileged pathogens represent the most common cause of lower respiratory tract infections.

The detection of travel-associated legionellosis can be extremely difficult; hence, an extensive case investigation is recommended in pneumonia-striken travellers and tourists, who are particularly at risk of acquiring the disease. On the Island of Ischia (Isola d'Ischia, Naples, Italy) a total of six cases of Legionnaires' disease occurred from 1986 to 1990. All patients (one man and two women from Germany, one Austrian woman, one Swiss man, and one Italian woman) had taken thermal baths and stayed in local hotels; they all experienced severe pneumonia, and three of them died. These cases were associated with hotels, and the hot-water supply was presumed to have transmitted the infection. Remedial procedures were applied to the hot-water plumbing of the hotels according to the WHO recommendations and were proved to be effective. The occurrences described in this paper stress the importance of rapid and accurate reporting of diagnosed cases to the country where the infection was probably acquired, in order to ensure early detection of endemic foci and emerging clusters of legionellosis.

Legionella infection was recognized as a cause of human disease in 1976, following the occurrence of an epidemic at Bellevue Stratford Hotel, Philadelphia, USA. In the subsequent years, various cases, both sporadic and epidemical, have been reported worldwide. In Italy, the first reports date from 1980. The compulsory notification of the disease was established in February 1983, and a few months later a National Surveillance Programme started operating at the Istituto Superiore di Sanità, Rome. Up to June 30, 1990, 542 confirmed cases of legionellosis were reported. For 249 of them, data of clinical and epidemiological significance are available. The incidence of the disease is higher in males (76% of total cases) and 51.5% of the patients are aged more than 50 years. During the clinical course, the occurrence of hepatic and/or renal dysfunction, cough, dyspnoea, diarrhoea and confusion was documented in a significant proportion of patients. The fatality rate was 12.4%. The disease occurred both sporadically and epidemically. Namely, clusters and outbreaks were detected all over the country, accounting for a total of 97 cases. Hospital patients should be regarded as an important category at risk for infection. The occurrence is also frequent among travellers and tourists, because of the stressing factors that may increase individual susceptibility, as well as the more frequent contact with infective sources. In Italy, the major risk of infection appears connected with water plumbing systems of hotels, residential houses and hospitals, where oxygen bubble-humidifiers have been found to represent an important source of infection. On the contrary, the association of human infection with air conditioning systems has not been evidenced up-to-now.

The authors report five Danish patients affected by Legionnaire's disease observed during the 1987 spring. They focus on the epidemiological, clinical, and therapeutic aspect of the outbreak.

Legionella pneumophila has frequently been recognised as a cause of infection in tourists. From 1973 to 1987, 117 cases of legionellosis were reported in tourists who spent one or more weeks in Italian summer resorts. 6 (5.1%) patients died. 42 (35.9%) were sporadic cases, and 75 (64.1%) were related to clusters or outbreaks. Among the 117 cases, 63 were reported to the Istituto Superiore di Sanità by the health authorities of other countries. Some travellers became ill while in Italy, others soon after they returned home. All tourists but two had stayed in hotels. L. pneumophila was isolated from the water system of 10 hotels, and in another hotel the same Legionella species was detected by direct immunofluorescence. Persistent and/or recurrent sources of infection seem to be present in some summer resorts on the Adriatic Coast and in the Lake Garda area in northern Italy. Some groups of cases were associated with particular hotels over a period of several months and sometimes years. Investigations have implicated potable water as the likely vehicle and the source of infection for tourists. The need of a greater awareness amongst clinicians that travel is a risk factor for legionellosis, and for better international surveillance and cooperation, is stressed.

The Authors report a rare case of Legionnaires' disease imported from Spain in a patient with beta-thalassaemia minor. This condition as predisposing factor for Legionella pneumophila infection is discussed, with particular emphasis on the therapeutic implications.

175 sera from children and 101 sera from adults both with respiratory illness of unknown origin were collected between September 1980 and February 1983 and studied by using the indirect immunofluorescence test for Legionnaires' disease. By using the criteria of the Center for Disease Control for a positive (fourfold increase in titer over 128 during convalescence) or presumptive (single titer greater than or equal to 256) serological test, 8 samples from adults (7.92%) and 11 samples from children (6.27%) gave a positive result. These results suggest that the frequency of Legionnaires' disease is similar in both adults and children.