Virulence of Legionella pneumophila strains isolated from hospital water system and healthcare-associated Legionnaires’ disease in Northern Italy between 2004 and 2009

OBJECTIVESTo define the scope of an outbreak of Legionnaires’ disease (LD), to identify the source, and to stop transmission.DESIGN AND SETTINGEpidemiologic investigation of an LD outbreak among patients and a visitor exposed to a newly constructed hematology-oncology unit.METHODSAn LD case was defined as radiographically confirmed pneumonia in a person with positive urinary antigen testing and/or respiratory culture forLegionellaand exposure to the hematology-oncology unit after February 20, 2014. Cases were classified as definitely or probably healthcare-associated based on whether they were exposed to the unit for all or part of the incubation period (2–10 days). We conducted an environmental assessment and collected water samples for culture. Clinical and environmental isolates were compared by monoclonal antibody (MAb) and sequence-based typing.RESULTSOver a 12-week period, 10 cases were identified, including 6 definite and 4 probable cases. Environmental sampling revealedLegionella pneumophilaserogroup 1 (Lp1) in the potable water at 9 of 10 unit sites (90%), including all patient rooms tested. The 3 clinical isolates were identical to environmental isolates from the unit (MAb2-positive, sequence type ST36). No cases occurred with exposure after the implementation of water restrictions followed by point-of-use filters.CONCLUSIONSContamination of the unit’s potable water system with Lp1 strain ST36 was the likely source of this outbreak. Healthcare providers should routinely test patients who develop pneumonia at least 2 days after hospital admission for LD. A single case of LD that is definitely healthcare associated should prompt a full investigation.Infect Control Hosp Epidemiol2017;38:306–313

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Persistence of the Same Strain ofLegionella pneumophilain the Water System of an Italian Hospital for 15 Years

Infection Control and Hospital Epidemiology ◽

10.1086/519869 ◽

2007 ◽

Vol 28 (9) ◽

pp. 1089-1092 ◽

Cited By ~ 22

Author(s):

M. Scaturro ◽

I. Dell'Eva ◽

F. Helfer ◽

M. L. Ricci

Keyword(s):

Legionella Pneumophila ◽

Molecular Typing ◽

Water System ◽

Northern Italy ◽

Italian Hospital ◽

Legionnaires Disease ◽

Predominant Strain

In 2004, an outbreak of legionnaires disease occurred in a hospital in northern Italy with a water system that had been disinfected multiple times since 1990 and equipped with a continuous disinfecting system. Molecular typing linked the outbreak to contamination of the hospital water system and demonstrated the persistence of a predominant strain ofLegionella pneumophilafor 15 years.

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Lab Diagnosis of Legionnaires’ Disease

JMS SKIMS ◽

10.33883/jms.v17i2.240 ◽

2014 ◽

Vol 17 (2) ◽

pp. 50-54

Author(s):

Nayeem U-Din Wani ◽

Aamir Ali

Keyword(s):

Legionella Pneumophila ◽

Water System ◽

Laboratory Diagnosis ◽

Significant Rise ◽

Control Measures ◽

Causative Organism ◽

Common Source ◽

Contaminated Water ◽

Atypical Pneumonia ◽

Legionnaires Disease

Legionnaires’ disease is a multi-system disease which causes atypical pneumonia due to Legionella bacteria, most commonly of the species Legionella pneumophila. About one out of every 10 people who get sick from Legionnaires’ disease will die. Most common source of infection-contaminated water supply through inhalation of contaminated water droplets (aerosols). A laboratory diagnosis of Legionnaires’ disease can be made using a variety of laboratory tests including: culture/isolation of the causative organism, antigen detection in urine, a significant rise in antibody titres or PCR methods. Determination of the monoclonal subtype and molecular sequence typing can support linking between strains from the sampled environment and from patients. The control measures available to reduce the amount of Legionella in a water system include structural adaptations to the water system, temperature control, disinfection using chemicals or other oxidizing materials, and use of biocides or installation of filters. JMS 2014;17(2):50-54

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Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor

Applied and Environmental Microbiology ◽

10.1128/aem.01275-14 ◽

2014 ◽

Vol 80 (19) ◽

pp. 6031-6036 ◽

Cited By ~ 2

Author(s):

Katie Laird ◽

Elena Kurzbach ◽

Jodie Score ◽

Jyoti Tejpal ◽

George Chi Tangyie ◽

...

Keyword(s):

Legionella Pneumophila ◽

Water System ◽

Severe Form ◽

Gas Chromatography Mass Spectrometry ◽

Free Living ◽

Content Type ◽

Soil Systems ◽

Viable Cells ◽

Legionnaires Disease ◽

Soil And Water

ABSTRACTLegionnaires' disease is a severe form of pneumonia caused byLegionellaspp., organisms often isolated from environmental sources, including soil and water.Legionellaspp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred,Legionellais particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor againstLegionellaspp. in water and in soil systems. Reductions of viable cells ofLegionella pneumophila,Legionella longbeachae,Legionella bozemanii, and an intra-amoebal culture ofLegionella pneumophila(water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1reduction inLegionellaspp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water wasL. pneumophila, with a 4-log cells ml−1reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controllingLegionellaspp. from environmental sources.

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Clusters of Healthcare-Associated Legionnaires’ Disease in Two Hospitals of Central Greece

Case Reports in Infectious Diseases ◽

10.1155/2018/2570758 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Maria A. Kyritsi ◽

Varvara A. Mouchtouri ◽

Anna Katsiafliaka ◽

Foteini Kolokythopoulou ◽

Elias Plakokefalos ◽

...

Keyword(s):

Legionella Pneumophila ◽

Environmental Samples ◽

Distribution Systems ◽

Water Distribution ◽

Control Measures ◽

Aerosol Therapy ◽

Environmental Investigation ◽

Source Of Infection ◽

Legionnaires Disease ◽

Healthcare Associated

Healthcare-associated Legionnaires’ disease often leads to fatal respiratory tract infection among hospitalized patients. In this report, three cases of Legionnaires’ disease among patients in two different hospitals (Hospital A and Hospital B) were investigated. After conducting an epidemiologic and environmental investigation, the water distribution systems (WDSs) were identified as the possible source of infection, as Legionella pneumophila serogroup 1 (Lp1) was isolated from both clinical and environmental samples. Patients received aerosol therapy with nebulizers during their hospitalization. Based on the results of the investigation, the hospitals’ infection control committees reviewed their policies for Legionnaires’ disease prevention and implemented control measures focusing on using sterile fluids for aerosol treatments.

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

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16071103 ◽

2019 ◽

Vol 16 (7) ◽

pp. 1103 ◽

Cited By ~ 5

Author(s):

Pasqualina Laganà ◽

Alessio Facciolà ◽

Roberta Palermo ◽

Santi Delia

Keyword(s):

Potential Risk ◽

Legionella Pneumophila ◽

Water Samples ◽

Continuous Monitoring ◽

Water System ◽

Hot Water ◽

University Hospital ◽

Environmental Surveillance ◽

Standard Procedures ◽

Legionnaires Disease

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.

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Legionella pneumophila in a hospital water system following a nosocomial outbreak: prevalence, monoclonal antibody subgrouping and effect of control measures

Epidemiology and Infection ◽

10.1017/s0950268800062002 ◽

1987 ◽

Vol 98 (3) ◽

pp. 253-262 ◽

Cited By ~ 18

Author(s):

C. D. Ribeiro ◽

S. H. Burge ◽

S. R. Palmer ◽

J. O'H. Tobin ◽

I. D. Watkins

Keyword(s):

Monoclonal Antibody ◽

Legionella Pneumophila ◽

Water Samples ◽

Water System ◽

Extended Period ◽

Control Measures ◽

Nosocomial Outbreak ◽

Water Supplies ◽

Chemical Sterilization ◽

Legionnaires Disease

SUMMARYSwabs and water samples from a hospital water system were cultured for legionellae over an extended period. Legionella pneumophila serogroup 1, including outbreak associated strains, were isolated in small numbers from approximately 5% of these samples despite implementation of the current DHSS/Welsh Office regulations. No cases of nosocomial legionnaires' disease were proven during the study. Physical cleaning and chemical sterilization of taps, and replacement of washers with ‘approved’ brands did not eradicate the organisms. Eradication of legionellae in hospital water supplies appears to be unnecessary in preventing nosocomial legionnaires' disease provided the current DHSS/Welsh Office recommendations are implemented.

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Legionellosis Outbreak Associated With a Hotel Fountain

Open Forum Infectious Diseases ◽

10.1093/ofid/ofv164 ◽

2015 ◽

Vol 2 (4) ◽

Cited By ~ 13

Author(s):

Shamika S. Smith ◽

Kathy Ritger ◽

Usha Samala ◽

Stephanie R. Black ◽

Margaret Okodua ◽

...

Keyword(s):

Legionella Pneumophila ◽

Laboratory Data ◽

Water System ◽

Respiratory Illness ◽

Environmental Testing ◽

Relative Risks ◽

Pontiac Fever ◽

Legionnaires Disease ◽

Favorable Conditions ◽

Cleaning And Disinfection

Abstract Background. In August 2012, the Chicago Department of Public Health (CDPH) was notified of acute respiratory illness, including 1 fatality, among a group of meeting attendees who stayed at a Chicago hotel during July 30–August 3, 2012. Suspecting Legionnaires' disease (LD), CDPH advised the hotel to close their swimming pool, spa, and decorative lobby fountain and began an investigation. Methods. Case finding included notification of individuals potentially exposed during July 16–August 15, 2012. Individuals were interviewed using a standardized questionnaire. An environmental assessment was performed. Results. One hundred fourteen cases were identified: 11 confirmed LD, 29 suspect LD, and 74 Pontiac fever cases. Illness onsets occurred July 21–August 22, 2012. Median age was 48 years (range, 22–82 years), 64% were male, 59% sought medical care (15 hospitalizations), and 3 died. Relative risks for hotel exposures revealed that persons who spent time near the decorative fountain or bar, both located in the lobby were respectively 2.13 (95%, 1.64–2.77) and 1.25 (95% CI, 1.09–1.44) times more likely to become ill than those who did not. Legionella pneumophila serogroup 1 was isolated from samples collected from the fountain, spa, and women's locker room fixtures. Legionella pneumophila serogroup 1 environmental isolates and a clinical isolate had matching sequence-based types. Hotel maintenance records lacked a record of regular cleaning and disinfection of the fountain. Conclusions. Environmental testing identified Legionella in the hotel's potable water system. Epidemiologic and laboratory data indicated the decorative fountain as the source. Poor fountain maintenance likely created favorable conditions for Legionella overgrowth.

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The Stafford outbreak of Legionnaires’ disease

Epidemiology and Infection ◽

10.1017/s0950268800047385 ◽

1990 ◽

Vol 104 (3) ◽

pp. 361-380 ◽

Cited By ~ 65

Author(s):

M. C. O'Mahony ◽

R. E. Stanwell-Smith ◽

H. E. Tillett ◽

D. Harper ◽

J. G. P. Hutchison ◽

...

Keyword(s):

Legionella Pneumophila ◽

Air Conditioning ◽

Cooling Tower ◽

Ventilation System ◽

Water System ◽

Cooling Water ◽

District General Hospital ◽

Control Measures ◽

Epidemic Strain ◽

Legionnaires Disease

SUMMARYA large outbreak of Legionnaires’ disease was associated with Stafford District General Hospital. A total of 68 confirmed cases was treated in hospital and 22 of these patients died. A further 35 patients, 14 of whom were treated at home, were suspected cases of Legionnaires’ disease. All these patients had visited the hospital during April 1985. Epidemiological investigations demonstrated that there had been a high risk of acquiring the disease in the out patient department (OPD), but no risk in other parts of the hospital. The epidemic strain ofLegionella pneumophila, serogroup 1, subgroup Pontiac la was isolated from the cooling water system of one of the air conditioning plants. This plant served several departments of the hospital including the OPD. The water in the cooling tower and a chiller unit which cooled the air entering the OPD were contaminated with legionellae. Bacteriological and engineering investigations showed how the chiller unit could have been contaminated and how an aerosol containing legionellae could have been generated in the U–trap below the chiller unit. These results, together with the epidemiological evidence, suggest that the chiller unit was most likely to have been the major source of the outbreak.Nearly one third of hospital staff had legionella antibodies. These staff were likely to have worked in areas of the hospital ventilated by the contaminated air conditioning plant, but not necessarily the OPD. There was evidence that a small proportion of these staff had a mild legionellosis and that these ‘influenza–like’ illnesses had been spread over a 5–month period. A possible explanation of this finding is that small amounts of aerosol from cooling tower sources could have entered the air–intake and been distributed throughout the areas of the hospital served by this ventilation system. Legionellae, subsequently found to be of the epidemic strain, had been found in the cooling tower pond in November 1984 and thus it is possible that staff were exposed to low doses of contaminated aerosol over several months.Control measures are described, but it was later apparent that the outbreak had ended before these interventions were introduced. The investigations revealed faults in the design of the ventilation system.

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Factors Influencing Legionella Contamination of Domestic Household Showers

Pathogens ◽

10.3390/pathogens8010027 ◽

2019 ◽

Vol 8 (1) ◽

pp. 27 ◽

Cited By ~ 6

Author(s):

Deanna Hayes-Phillips ◽

Richard Bentham ◽

Kirstin Ross ◽

Harriet Whiley

Keyword(s):

Risk Factors ◽

Water Temperature ◽

Legionella Pneumophila ◽

Public Awareness ◽

Water System ◽

South Australia ◽

Hot Water ◽

Factors Associated ◽

Potential Source ◽

Legionnaires Disease

Legionnaires’ disease is a potentially fatal pneumonia like infection caused by inhalation or aspiration of water particles contaminated with pathogenic Legionella spp. Household showers have been identified as a potential source of sporadic, community-acquired Legionnaires’ disease. This study used qPCR to enumerate Legionella spp. and Legionella pneumophila in water samples collected from domestic showers across metropolitan Adelaide, South Australia. A survey was used to identify risk factors associated with contamination and to examine awareness of Legionella control in the home. The hot water temperature was also measured. A total of 74.6% (50/68) and 64.2% (43/68) showers were positive for Legionella spp. and L. pneumophila, respectively. Statistically significant associations were found between Legionella spp. concentration and maximum hot water temperature (p = 0.000), frequency of shower use (p = 0.000) and age of house (p = 0.037). Lower Legionella spp. concentrations were associated with higher hot water temperatures, showers used at least every week and houses less than 5 years old. However, examination of risk factors associated with L. pneumophila found that there were no statistically significant associations (p > 0.05) with L. pneumophila concentrations and temperature, type of hot water system, age of system, age of house or frequency of use. This study demonstrated that domestic showers were frequently colonized by Legionella spp. and L. pneumophila and should be considered a potential source of sporadic Legionnaires’ disease. Increasing hot water temperature and running showers every week to enable water sitting in pipes to be replenished by the municipal water supply were identified as strategies to reduce the risk of Legionella in showers. The lack of public awareness in this study identified the need for public health campaigns to inform vulnerable populations of the steps they can take to reduce the risk of Legionella contamination and exposure.

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