A hot water supply as the source of Legionella pneumophila in incubators of a neonatology unit

The humidification trays of five of seven incubators in a neonatology unit of a hospital were found to be colonized with Legionella pneumophila, serogroup 1. Bacteriological analysis of the water in the humidification trays showed very large numbers of heterotrophic bacteria, one of which also contained Pseudomonas aeruginosa. Two hot water systems supply the neonatology unit, either of which is used to add water to the humidification trays; one system (A) is maintained at about 60 degrees C, while the other system (B) is maintained at 45 degrees C. The latter was also found to be colonized with L. pneumophila, Sg1. Monoclonal antibody (Mab) subgrouping of the isolates, indicated that system B was the source of colonization of the humidification trays of the incubators.     

Pneumonia due to Legionella pneumophila in an immunocompromised child

A one-year-and-seven-months-old boy was hospitalised because of fever, cough and general malaise. A diagnosed tonsillitis and pneumonia were treated with intravenous antibiotics. His clinical condition worsened despite antibiotic therapy. After immunologic investigations revealed both a cellular and a humoral immune disorder, a broncho-alveolar lavage was performed. The culture revealed Legionella pneumophila. Antibiotic treatment was then changed to erythromycin in combination with rifampicin, with a good response. Although rarely described in childhood, one should consider L. pneumophila as a possible pathogen in immunocompromised children presenting with pneumonia.     

Soil as a source of Legionella pneumophila serogroup 1 (Lp1)

OBJECTIVE: To investigate the potential source of a case of Legionnaires' disease caused by an unusual serotype of Legionella pneumophila serogroup 1 (Lp1) in regional Victoria in May 2001. METHOD: Epidemiological and environmental investigation of the source of infection of a case of Legionnaires' disease in regional Victoria in May 2001. RESULTS: Extensive environmental investigations did not reveal any cooling water tower systems close to the residence or the shopping centre that the case visited prior to illness. The sputum culture and a soil sample from the field at the plant nursery where the case worked prior to illness were both positive for Legionella pneumophilia serogroup 1, MDU pulsovar 97:103. CONCLUSION: Legionella pneumophila has been found in soil and was further found to be associated with a case of Legionella pneumophila. IMPLICATIONS: Public health authorities should consider exposures to soil and potting mixes when investigating cases of Legionella pneumophila where the case has no apparent association with cooling towers. Safe gardening practices should be promoted among the community.     

Factors predisposing to Legionella pneumophila colonization in residential water systems

Fifty-five homes in the Pittsburgh area were surveyed for the presence of Legionella pneumophila colonization. Hot water tanks, faucets, and showerheads were sampled. Six homes yielded Legionella pneumophila within the water distribution system. Lower water temperatures (less than 48.8 degrees C) within the hot water system were significantly associated with the presence of L. pneumophila colonization. A similar association was found for electric heaters; however, this association may be an indirect one. Water temperatures in electrically heated tanks were significantly lower than in gas-heated tanks. City residences were also more likely to be colonized than suburban residences. Because acquisition of Legionnaires' disease in the community has been linked to colonization of the water supplies in the homes of affected patients, these findings may have clinical implications for susceptible individuals residing in homes with water supplies colonized by L. pneumophila.     

Endemicity of Legionella pneumophila serogroup 3 in a hospital water supply

A microbiological and epidemiological investigation at the Infectious Diseases Hospital in Turin, Italy, demonstrated Legionella pneumophila serogroup 3 at 10(2) to greater than 4 X 10(3) cfu l-1 from 24 of 32 hot water samples collected from hand-basins in six separate buildings. A sample taken from the public water supply, and a hot water sample (80 degrees C) collected from hot water tanks, did not yield legionellas. Legionella pneumophila serogroup 3 was found in samples taken at the first point of mixed hot and cold water (50 degrees C) at 3 X 10(2) cfu l-1. 12 of 26 samples from the shower-heads yielded 10(3) to 2.5 X 10(5) cfu l-1 and one of 12 water samples from oxygen bubble humidifiers tested yielded 1.6 X 10(4) cfu l-1. No other legionellas species or serogroups of Legionella pneumophila were isolated during the study. No cases of nosocomial pneumonia were detected among 3653 patients' records, nor was there serological evidence of Legionella infection in the 180 patients tested.     

Genetic diversity of Legionella pneumophila in hospital water systems

It has been shown that different patients who had acquired legionellosis in a hospital setting were infected with the same strain even years apart. However, there are no longitudinal data describing the molecular epidemiology of Legionella pneumophila strains that contaminate a water system. This raised the question if there are any shifts of L. pneumophila strains over time, or after carrying out control measures. Using genotyping on a large collection of isolates, we investigated in a retrospective study the distribution of L. pneumophila serogroups and PFGE types in six different hospitals of the University of Heidelberg between 1991 and 2001. A total of 2012 water samples were drawn for routine testing and for evaluation of control measures, 747 samples were positive for L. pneumophila. Serogroups were determined by latex agglutination or by direct fluorescence assay; and 515 L. pneumophila isolates from water systems and six from patients underwent PFGE typing after SfiI-restriction. We identified seven serogroups and 19 genotypes among the water isolates. Each hospital had one to four predominating PFGE types that were stable over the investigation period. The oldest buildings in hospitals 4 and 5 (built 1876 and 1907) had more types than the newest one (built 1986). In all hospitals PFGE types were identified that could be found only sporadically. Although each hospital had its own warm water supply, we identified types that could be found in more than one hospital. However, there was no overlap of types in buildings that were fed from different wells. Infrequently occurring nosocomial legionellosis (n=3) were only caused by predominant strains. Contamination of water supplies seemed to be dominated by stable genotypes, even after various control measures. Additional genotypes could be isolated sporadically, however, their pathogenetic relevance seemed to be questionable.     

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

Swabs 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.     

Evaluation of a Legionella urinary antigen enzyme immunoassay for rapid detection of Legionella pneumophila in water samples

Despite advances in medium formulations and pretreatment techniques, recovery of Legionella from water samples can still be quite low, difficult and time consuming. The aim of this study was to evaluate the utility of a Legionella urinary antigen enzyme immunoassay (Bartels ELISA, Trinity Biotech, Ireland) for the detection of Legionella in water samples. Reference ATCC Legionella strains were used to spike water samples to a final concentration of 10⁴–10⁵ cfu/ml. The lower detection limit of the test for all Legionella pneumophila serogroups was assessed by serial dilutions of spiked water samples. Legionella antigen was detected in all filtered samples except for those spiked with L. bozemanii and L. longbeachae. The lower detection limit for soluble L. pneumophila serogroup 1 antigen was 780 cfu/ml. Bartels ELISA could be a useful method for antigen detection in water samples when a high recovery of L. pneumophila is suspected. The test could be used as a rapid screening method for the detection of Legionella in a large number of samples. However, the low sensitivity of the test requires to keep on performing conventional culture for isolation and for further studies on isolated bacteria.     

Atypical legionellosis: isolation of Legionella pneumophila serogroup 1 from a patient with aspiration pneumonia

It has been suspected that the number of Legionella pneumophila infections is substantially higher than commonly reported, due to subclinical infections. We report a patient where the diagnosis of a legionella infection was made only because of a large-scale surveillance programme for legionellosis. The case demonstrates the possibility of legionellas being involved in lung disease though not necessarily causing overt legionellosis.     

Persistence of Legionella pneumophila in a hospital's water system: a 13-year survey.

OBJECTIVE: To describe the molecular epidemiology of Legionella pneumophila infections in the University of Iowa Hospitals and Clinics (UIHC). DESIGN: Molecular epidemiological study using pulsed-field gel electrophoresis (PFGE). SETTING: A large university teaching hospital. ISOLATES: All surviving isolates obtained from culture-proven nosocomial L. pneumophila infections and all surviving isolates obtained from the University of Iowa Hospital and Clinics' water supply between 1981 and 1993. RESULTS: Thirty-three isolates from culture-proven nosocomial cases of L. pneumophila pneumonia were available for typing. PFGE of genomic DNA from the clinical isolates identified six different strains. However, only strain C (16 cases) and strain D (13 cases) caused more than 1 case. Strain C caused clusters of nosocomial infection in 1981, 1986, and 1993 and also caused 4 sporadic cases. Strain D caused a cluster in 1987 and 1988 plus 4 sporadic cases. Of the six strains causing clinical infections, only strains C and D were identified in water samples. PFGE identified three strains in the water supply, of which strains C and D caused clinical disease and also persisted in the water supply during most of the study period. CONCLUSION: Specific strains of L. pneumophila can colonize hospital water supplies and cause nosocomial infections over long periods of time.     

工业循环冷却塔水嗜肺军团菌分离株分子生学特性研究

目的 了解钢铁企业工业循环冷却塔水中的嗜肺军团菌污染状况及菌株分子生物学特性.方法 于2011年3月-2012年9月对邯郸某钢铁厂相对固定的车间冷却塔水进行连续监测,进行嗜肺军团菌的定量分离培养,对分离到的菌株进行血清分型、脉冲场凝胶电泳分型、基因序列分型、毒力基因(lvh、rtxA)检测.结果 共检测117份水样,其中20份水样检出嗜肺军团菌,检出率为17.1％;菌落总数为100～50000 CFU/L,中位数为12000 CFU/L;共分离到嗜肺军团菌23株,血清型包括Lp1、Lp3、Lp5、Lp6、Lp8,并以Lp1为主(占36.1％,9/23).23株嗜肺军团菌PFGE分型得到19种不同带型,其中15种带型为国内首次发现.23株嗜肺军团菌分成20个SBT型别,有12个型别为本研究新发现.23株菌中,lvh、rtxA基因阳性的分别有20、22株,两种毒力基因全部阳性的有19株.结论 钢铁企业的冷却塔水存在嗜肺军团菌污染,菌型呈现基因多态性,同时具有独特的基因组成,并普遍具有毒力.     

Legionella pneumophila serogroup 12 pneumonia in a renal transplant recipient: case report and environmental observations

We describe the first reported case of pneumonia due to Legionella pneumophila serogroup 12 in the UK. This hospital-associated infection occurred in an immuno-incompetent patient and coincided with a change in character of the local environmental strains of legionellas. The patient produced a serological response both to her own isolate and to L. pneumophila serogroups 1-6. Thus serodiagnosis was attainable using the usual screening antigens.     

浙江省首次从空调冷却塔水中分离到军团菌

经过研究发现,水是军团菌的自然栖息地,所以含军团菌的水产生的气溶胶就成为传播军团菌病的关键环节。我们对杭州市外环境中央空调冷却塔水中的军团菌进行了监测,现将结果报告如下。     

Detection of Legionella pneumophila in environmental water samples using a fluorescein conjugated monoclonal antibody

Sixty-three environmental water samples from various sources were examined for the presence of Legionella pneumophila with a commercially available direct fluorescent monoclonal antibody (GS), an indirect fluorescent antibody test (IFAT) and culture. GS detected L. pneumophila in 94% and 100% of environmental water samples which were culture and IFAT positive for L. pneumophila, respectively. IFAT detected 69% of L. pneumophila culture positive samples. Cultures of L. pneumophila serogroups 1 to 12, 14 and non-L. pneumophila bacteria which may be found in water, and bacteria containing non-specific binding proteins, were stained by GS and IFAT. GS identified all serogroups of L. pneumophila and did not cross react with any non-L. pneumophila bacteria. L. pneumophila in environmental samples was easy to detect against a clear dark background when stained with GS.     

深圳公共场所水系统嗜肺军团菌污染研究

目的了解深圳公共场所水系统嗜肺军团菌污染现状,为卫生监督管理提供依据。方法依照《公共场所集中空调通风系统卫生规范》附录A方法,随机采集本市177家公共场所冷却水、冷凝水、淋浴水、泳池水、生活饮用水共500份水样,检测嗜肺军团菌及其菌型。结果冷却水、冷凝水、淋浴水嗜肺军团菌检出率分别为11.0%(28/255)、1.1%(2/176)、30.0%(12/40),泳池水、生活饮用水未检出嗜肺军团菌;酒店、公共浴室、候诊室、地铁站冷却水嗜肺军团菌检出率分别为18.1%(19/105)、4.0%(1/25)、31.8%(7/22)、0.1%(1/103),差异有统计学意义(χ2=11.74,P<0.05);分离出44株嗜肺军团菌,菌型以LP1型为主,占70.5%(31/44),LP3型、LP6型分别占2.3%(1/44)、27.2(12/44)。结论本市公共场所空调冷却水和冷凝水、淋浴水受嗜肺军团菌污染,存在健康隐患,应加强空调系统和淋浴-热水系统的清洗消毒。