Legionella longbeachae detected in an industrial cooling tower linked to a legionellosis outbreak, New Zealand, 2015; possible waterborne transmission?

A legionellosis outbreak at an industrial site was investigated to identify and control the source. Cases were identified from disease notifications, workplace illness records, and from clinicians. Cases were interviewed for symptoms and risk factors and tested for legionellosis. Implicated environmental sources were sampled and tested for legionella. We identified six cases with Legionnaires' disease and seven with Pontiac fever; all had been exposed to aerosols from the cooling towers on the site. Nine cases had evidence of infection with either Legionella pneumophila serogroup (sg) 1 or Legionella longbeachae sg1; these organisms were also isolated from the cooling towers. There was 100% DNA sequence homology between cooling tower and clinical isolates of L. pneumophila sg1 using sequence-based typing analysis; no clinical L. longbeachae isolates were available to compare with environmental isolates. Routine monitoring of the towers prior to the outbreak failed to detect any legionella. Data from this outbreak indicate that L. pneumophila sg1 transmission occurred from the cooling towers; in addition, L. longbeachae transmission was suggested but remains unproven. L. longbeachae detection in cooling towers has not been previously reported in association with legionellosis outbreaks. Waterborne transmission should not be discounted in investigations for the source of L. longbeachae infection.

Atypical pneumonia.

PURPOSE OF REVIEW: We present the key advances in the infections that clinicians conventionally associate with atypical pneumonia: legionellosis, Mycoplasma pneumonia, Chlamydophila species pneumonia and Q fever. RECENT FINDINGS: There have been significant developments in molecular diagnosis to include Mycoplasma pneumoniae and Chlamydophila pneumoniae in multiplex PCR of respiratory specimens. There are diagnostic challenges in distinguishing carriage from infection, which is recognized in C. pneumoniae and now also evident in M. pneumoniae. Macrolide-resistant M. pneumoniae has emerged in Asia. There are new antimicrobials on the horizon in the ketolide class with activity against typical and atypical pathogens and useful empirical agents. SUMMARY: There are few advances in our knowledge of the epidemiology of atypical pathogens or the effectiveness of antimicrobial therapy--empirical or pathogen specific. However, if molecular testing becomes widely implemented, there will be an increased understanding of the epidemiology and presentation of atypical pneumonia and a shift to more targeted antimicrobial therapy.

Neumonía por Legionella pneumophila asociada al uso de un humidificador doméstico en una niña inmunocompetente / Legionella pneumophila pneumonia associated with the use of a home humidifier in an immunocompetent girl

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Prevalence of Legionella strains in cooling towers and legionellosis cases in New Zealand.

Over 3,900 water samples from 688 cooling towers were tested for Legionella in 2008 in New Zealand. Of 80 (2.05% isolation rate) Legionella isolates, 10 (12.5%) were L. pneumophila serogroup 1; 10 (12.5%) were L. anisa; nine (11.2%) were L. pneumophila serogroup 8; and one (1.2%) was L. longbeachae serogroup 2. Forty-one (51.2%) Legionella isolates were L. pneumophila serogroups. Over 3,990 water samples from 606 cooling towers were tested for Legionella in 2009 in New Zealand. Of 51 (1.28% isolation rate) Legionella isolates, 18 (35.3%) were L. pneumophila serogroup 1, and 39 (76.4%) were other L. pneumophila serogroups. L. pneumophila serogroups were significantly associated with legionellosis cases in 2008 and 2009. L. longbeachae serogroups were equally significantly associated with legionellosis cases. This significant association of L. longbeachae with legionellosis particularly of L. longbeachae serogroup 1 is unique in that part of the world. The authors' study also showed that the aqueous environment of the cooling tower is not a natural habitat for pathogenic L. longbeachae. Regular monitoring and maintenance of cooling towers have prevented outbreaks of legionellosis.

[Spa facilities and legionellosis: legislative structure and state of the art in Apulia (Italy)]. / Strutture termali e legionellosi: quadri normativi e stato dell'arte in Puglia.

A number of factors, for example water temperature, can encourage the growth of microorganisms such as Legionella spp in spa facilities. Individuals who attend this type of facility are often subjects at risk for infection who are undergoing inhalation therapy and hot tub treatments. A very accurate management of these facilities is therefore required to avoid infection by Legionella spp. The purpose of this study was to verify the current Italian national and Apulia regional legislation regarding the control of contamination by Legionella spp. in spa facilities.

Increase of cases of legionellosis in Latvia, 2011.

An increased number of legionellosis cases in 2011 has been reported in Latvia, compared to the ten previous years. A total of 30 legionellosis cases (1.35 per 100,000 inhabitants), including 19 females, have been confirmed until the end of September 2011. The majority of cases (n=23) were inhabitants of the capital city Riga. The reason for the increase in legionellosis is unclear. Twenty-six of the 30 cases are not travel-related.

Diversidad de subtipos de Legionella pneumophila en torres de refrigeración: estudios de cinética de crecimiento y virulencia / Diversity of Legionella pneumophila in cooling towers: coculture kinetics and virulence studies

IntroducciónLegionella pneumophila (L. pneumophila) fue aislada en tres torres de refrigeración implicadas en tres brotes de legionelosis comunitaria. En cada una de ellas se encontraron cepas con dos subtipos diferentes de ADN cromosómico. Sin embargo, sólo uno de ellos era idéntico al de las cepas clínicas. Para intentar entender porque solo una de las cepas ambientales produjo los casos clínicos investigamos la virulencia intrínseca de estas cepas.MétodosSe seleccionaron 6 cepas de L. pneumophila sg.1: dos cepas (A1 y B1) procedentes de la torre de refrigeración 1, dos cepas (A2 y B2) de la torre 2 y dos cepas (A3 y B3) de la torre 3. Las cepas A presentaban un perfil de ADN cromosómico idéntico a la cepa clínica aislada en los individuos afectados en cada uno de los brotes de legionelosis. La cepa B presentaba un perfil cromosómico diferente. Se realizaron ensayos de replicación en macrófagos, se determinó la presencia del epítopo reconocido por MAb 3/1 y se estudió la cinética de crecimiento en medio BCYE. Las cepas se tipificaron mediante electroforesis en campo pulsante.ResultadosLas cepas A no presentaron mayor grado de virulencia, sin embargo, fueron capaces de crecer y sobrevivir mejor que las cepas B en medio BCYE.ConclusionesEstos resultados sugieren que las cepas mejor adaptadas al medio conseguirán desplazar a las demás y serán capaces de propagarse e infectar a los humanos. La adaptación a las condiciones ambientales podría desempeñar un papel importante en la patogenia de cada cepa (AU)

Background: Legionella pneumophila (L. pneumophila) was isolated from three cooling towers involved inthree community outbreaks of Legionnairesˇı disease. Each cooling tower had two different chromosomalDNA subtypes. However, only one matched identically to the clinical strains. To try to understand whyonly one of the environmental strains caused clinical cases we investigated the intrinsic virulence ofthese strains.Methods: We selected six strains of L. pneumophila sg.1: two strains (A1 and B1) from cooling tower1, two strains (A2 and B2) from tower 2 and two strains (A3 and B3) from tower 3. One of the twosubtypes (A) exhibited the same chromosomal DNA subtype as the strains isolated from the patientsin each outbreak and the other exhibited a different subtype. The replication within macrophages, thepresence of lipopolysaccharide epitope recognized by MAb 3/1 and the growth kinetics in BCYE brothwere investigated. Isolates were typed by pulsed field electrophoresis. Results: The A strains did not have a higher virulence level, but were able to grow and survive better thanstrains B in BCYE broth.Conclusions: These results suggest that the strains better adapted to the environment will manage todisplace the others and will be able to spread and infect humans. The adaptation to the environmentalconditions could play an important role in the pathogenesis of the strains (AU)

Legionella longbeachae and legionellosis.

Reported cases of legionellosis attributable to Legionella longbeachae infection have increased worldwide. In Australia and New Zealand, L. longbeachae has been a known cause of legionellosis since the late 1980s. All cases for which a source was confirmed were associated with potting mixes and composts. Unlike the situation with other Legionella spp., L. longbeachae-contaminated water systems in the built environment that cause disease have not been reported. Spatially and temporally linked outbreaks of legionellosis associated with this organism also have not been reported. Sporadic cases of disease seem to be limited to persons who have had direct contact with potting soil or compost. Long-distance travel of the organism resulting in infection has not been reported. These factors indicate emergence of an agent of legionellosis that differs in etiology from other species and possibly in route of disease transmission.

Legionella--every infection preventionist's dream--or is it?

Legionella is an underreported disease challenge within the hospital setting. In order to combat Legionella during times of construction and renovation, infection preventionists must become construction experts. The infection preventionist must be able to plan for potential waterborne disease outbreaks and protect the hospital staff, patients and visitors from waterborne pathogens. Legionella's history, signs and symptoms, diagnostic testing and treatment will be discussed. The hospital's convening of a multidisciplinary Legionella task force to work cohesively to develop a waterborne pathogens plan will also be discussed. This article was written from the perspective of the infection preventionist and employee health nurse at the time of the Legionella outbreak at their hospital.

Effective environmental sampling strategies for monitoring Legionella spp contamination in hot water systems.

BACKGROUND: The prevention and control of legionellosis in hospital settings involves environmental sampling, among other measures. The data yielded by sampling constitute an important means of risk assessment and provide a valid basis on which to plan remedial (cleansing and disinfection) and preventive (maintenance) interventions. This retrospective study had 2 objectives: (1) to evaluate the utility of biofilm sampling at distal sites and (2) to identify an efficient environmental sampling strategy. METHODS: Samples of hot water and biofilm were collected between June 1999 and March 2008 from 41 hospitals in Italy's Piemonte region. We analyzed results of the samples (water and biofilm) taken from the same site and results of the water samples taken from the recirculation loop and water samples taken from the distal sites during the same sampling run. RESULTS: Microbiological analysis was performed on 3910 pairs of samples (water/biofilm). In 81% of the pairs, the results were concordant; in 17% of the pairs, Legionella was isolated only from the water samples, and in only 2% of the pairs was Legionella isolated from the biofilm sample alone. Data from 299 sampling runs show that 79% (236) of results from the water samples taken from the recirculation loop and water samples taken from the distal sites during the same sampling run were concordant, and 21% (63) were discordant. CONCLUSIONS: Our findings suggest that hospitals could safely adopt a simpler (water sampling only without biofilm sampling) and more efficient (monitoring of the entire system through sampling of recirculation loop water) environmental sampling policy.

Legionella bacteria in shower aerosols increase the risk of Pontiac fever among older people in retirement homes.

BACKGROUND: 828 elderly subjects residing in nursing homes were followed up during 4 months to ascertain incidence of symptoms associated with Pontiac fever (PF) in a non-epidemic setting. METHODS: The exposure situation was inhalation of Legionella bacteria while showering. An audit of the hot water system in all institutions allowed ascribing each subject to a water quality area wherefrom one shower was sampled for Legionella assays at the end of the follow-up period. Legionella were detected in water and aerosols using the culture (CFU, colony forming units) and in situ hybridization (FISH) techniques. RESULTS: Among 32 Pontiac-like episodes, 29 cases complied with the operational definition of PF elaborated for this study. Incidence density was 0.11 case/person-year (95% CI 0.07 to 0.15). Water concentrations greater than 105 Legionella FISH/l and 104 Legionella CFU/l were associated with an increased risk of PF (respectively RR 2.23, p = 0.05 and RR 2.39, p = 0.11, with significant dose-response patterns: p for trend <0.04). The condition also seems associated with aerosol concentrations above 103 Legionella FISH/l of air. A significantly higher risk of Pontiac-like episodes (RR 6.24, 95% CI 2.12 to 18.38) was seen for elderly subjects receiving corticosteroid therapy. CONCLUSION: The water and threshold values identified in this research could be used to inform guidance measures aimed at protecting institutionalised older people from Legionnaires' disease. Immunosuppressive therapy in the same population group can significantly enhance susceptibility to Legionella bacteria.

Legionella contamination in the water system of hospital dental settings.

BACKGROUND AND AIM OF THE WORK: Among hospital facilities the dental unit is an environment that is at major risk of Legionella due to equipment such as the air/water syringe, the turbine, the micromotor and the scaler which generate potentially harmful aerosols that may to be a source of exposure to Legionella spp. particularly in immunodeficient patients, and those affected by chronic diseases, and also in dental personnel. Therefore, an examination of the extent of Legionella spp. contamination in the dental chairs waterlines and the incoming water supply of some public dental units is the subject of the present study. METHODS: From February 2002 to March 2004, a total of 208 water samples were collected: 160 samples from the water supply of 4 dental chair and 48 samples from the cold incoming tap water of 2 units. RESULTS: Legionella spp. was detected in 46 samples (22.1% ): 19 of them (41.3% of Legionella spp.; 9.1% of the total) were Legionella pneumophila; Pseudomonas aeruginosa was detected in 86 samples (41.4%) and both microorganisms were detected in 2 samples (0.96%). CONCLUSIONS: Our results show a microbiological condition in dental settings, that is not at all satisfactory due to the presence of Legionella in concentrations that are considered to be a health hazard (> or = 10(3)) in certain cases. Given the extent of the health risk in these surroundings, the difficulty in its assessment, and also considering the wide diffusion of general dental care, our investigation has confirmed the need to regularly monitor the microbiological condition of water in dental units.

Does using potting mix make you sick? Results from a Legionella longbeachae case-control study in South Australia.

A case-control study was performed in South Australia to determine if L. longbeachae infection was associated with recent handling of commercial potting mix and to examine possible modes of transmission. Twenty-five laboratory-confirmed cases and 75 matched controls were enrolled between April 1997 and March 1999. Information on underlying illness, smoking, gardening exposures and behaviours was obtained by telephone interviews. Recent use of potting mix was associated with illness (OR 4.74, 95% CI 1.65-13.55, P=0.004) in bivariate analysis only. Better predictors of illness in multivariate analysis included poor hand-washing practices after gardening, long-term smoking and being near dripping hanging flower pots. Awareness of a possible health risk with potting mix protected against illness. Results are consistent with inhalation and ingestion as possible modes of transmission. Exposure to aerosolized organisms and poor gardening hygiene may be important predisposing factors to L. longbeachae infection.

[Legionellosis]. / La légionellose.

Although one does not find the origin of the contamination in the human half of the cases of legionellosis, one knows that this disease is the consequence of the almost obligatory contamination of the networks of installations of hot water by Legionella pneumophila, and the inhalation by the man of infected droplets. Pathology generally consists of a relatively serious pneumopathy. The control of the level of contamination of the various producing hydrous installations of aerosols is imperative to avoid the serious medical consequences, which cannot be prevented by an action on the human target. The majority of the currently identified tanks are the air and cool towers and the distribution networks of hot water. The taking into account of this risk in the hospitals or thermal led to the implementation of many measurements of disinfection and control, which start to show a certain effectiveness on which has occurred of new cases in these establishments, today in clear reduction.

Clinical-environmental surveillance of legionellosis: an experience in Southern Italy.

In Italy, although the number of cases of legionellosis notified to the health authorities has significantly increased in recent years, the incidence is still believed to be underestimated. To verify the true frequency and identify the sources of infection, an active clinical-environmental surveillance program was instituted in three hospital facilities in Southern Italy. Between January 2001 and March 2005, a total of 1000 patients admitted to the three hospitals with a diagnosis of pneumonia were enrolled. The urinary antigen and anti-Legionella antibody titre were assayed in each subject, and direct searches for the microorganism were made in biological specimens. Legionellosis was found to be present in 5.9% of the patients. For each of the cases of legionellosis, microbiological surveys were made of the water supply in the public and/or private facilities involved. Overall, 197 water samples of hospital origin and 218 of community origin were analysed: Legionella spp was isolated in 44.2 and 36.7% of the cases, respectively. Comparison of our data with those of the routine surveillance system for the same area (only 7 cases during the period 1997-2000), showed that the frequency of legionellosis is grossly underestimated in Southern Italy. It is therefore necessary to set up more rigorous controls in both hospital and community facilities, so that timely preventive measures can be taken to avoid any further spread of the disease.

Legionella bacteria and water systems in health care premises.

Legionnaires' disease (Legionellosis) is a bacterial pneumonia that acquired its name following an outbreak of pneumonia among army veterans attending an American Legion convention in Philadelphia in 1976. The previously undiscovered bacterium that caused this form of pneumonia was therefore named Legionella. There are more than 45 species of Legionella bacteria and these are natural inhabitants of water supplies throughout the world (Fliermans, 1981). About half of these have been associated with infection, although the most common cause of Legionnaires' disease is Legionella pneumophila, which is the causative strain in around 90 per cent of cases (Fields et al, 2002).