Legionella pneumonia due to exposure to 24-hour bath water contaminated by Legionella pneumophila serogroup-5

Energy Conservation and the Promotion of Legionella pneumophila Growth: The Probable Role of Heat Exchangers in a Nosocomial Outbreak

OBJECTIVE

To determine the source of a Legionella pneumophila serogroup 5 nosocomial outbreak and the role of the heat exchanger installed on the hot water system within the previous year.

SETTING

A 400-bed tertiary care university hospital in Sherbrooke, Canada.

METHODS

Hot water samples were collected and cultured for L. pneumophila from 25 taps (baths and sinks) within wing A and 9 taps in wing B. Biofilm (5) and 2 L water samples (3) were collected within the heat exchangers for L. pneumophila culture and detection of protists. Sequence-based typing was performed on strain DNA extracts and pulsed-field gel electrophoresis patterns were analyzed.

RESULTS

Following 2 cases of hospital-acquired legionellosis, the hot water system investigation revealed a large proportion of L. pneumophila serogroup 5 positive taps (22/25 in wing A and 5/9 in wing B). High positivity was also detected in the heat exchanger of wing A in water samples (3/3) and swabs from the heat exchanger (4/5). The outbreak genotyping investigation identified the hot water system as the source of infections. Genotyping results revealed that all isolated environmental strains harbored the same related pulsed-field gel electrophoresis pattern and sequence-based type.

CONCLUSIONS

Two cases of hospital-acquired legionellosis occurred in the year following the installation of a heat exchanger to preheat hospital hot water. No cases were reported previously, although the same L. pneumophila strain was isolated from the hot water system in 1995. The heat exchanger promoted L. pneumophila growth and may have contributed to confirmed clinical cases.

Infect. Control Hosp. Epidemiol. 2016;1475–1480

Applicability assessment of ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ to the eradication of Legionella in rainwater storage tanks for household use

Water environments appear to be the habitats of Legionella species. Legionellosis is considered as a preventable illness because bacterial reservoirs can be controlled and removed. Roof-harvested rainwater has attracted significant attention not only as a groundwater recharge but also as a potential alternative source of nonpotable water. We successfully developed ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ using the thermal spraying method. The ceramic microbeads were demonstrated to have bactericidal activities against not only Legionella but also coliform and heterotrophic bacteria. Immersing the ceramic microbeads in household rainwater storage tanks was demonstrated to yield the favorable eradication of Legionella organisms. Not only rapid-acting but also long-lasting bactericidal activities of the ceramic microbead were exhibited against Legionella pneumophila. However, time-dependent attenuation of the bactericidal activities against Legionella were also noted in the sustainability appraisal experiment. Therefore, the problems to be overcome surely remain in constantly managing the Legionella-pollution by means of immersing the ceramic microbeads. The results of our investigation apparently indicate that the earthplus™-coated ceramic microbeads would become the favorable tool for Legionella measures in household rainwater storage tanks, which may become the natural reservoir for Legionella species. Our investigation would justify further research and data collection to obtain more reliable procedures to microbiologically regulate the Legionella in rainwater storage tanks.

Confirmed and Potential Sources of Legionella Reviewed

Legionella bacteria are ubiquitous in natural matrices and man-made systems. However, it is not always clear if these reservoirs can act as source of infection resulting in cases of Legionnaires' disease. This review provides an overview of reservoirs of Legionella reported in the literature, other than drinking water distribution systems. Levels of evidence were developed to discriminate between potential and confirmed sources of Legionella. A total of 17 systems and matrices could be classified as confirmed sources of Legionella. Many other man-made systems or natural matrices were not classified as a confirmed source, since either no patients were linked to these reservoirs or the supporting evidence was weak. However, these systems or matrices could play an important role in the transmission of infectious Legionella bacteria; they might not yet be considered in source investigations, resulting in an underestimation of their importance. To optimize source investigations it is important to have knowledge about all the (potential) sources of Legionella. Further research is needed to unravel what the contribution is of each confirmed source, and possibly also potential sources, to the LD disease burden.

Bath water contamination with Legionella and nontuberculous mycobacteria in 24-hour home baths, hot springs, and public bathhouses of Nagano Prefecture, Japan

Bath water samples were collected from 116 hot springs, 197 public bathhouses, and 38 24-hour home baths in Nagano Prefecture, Japan, during the period of April 2009 to November 2011, for determining the presence and extent of contamination with Legionella and nontuberculous mycobacteria. Cultures positive for Legionella were observed in 123 of the 3,314 bath water samples examined. The distribution and abundance of Legionella and/or combined contamination with Legionella and nontuberculous mycobacteria were investigated to clarify the contamination levels. The abundance of Legionella was demonstrated to correlate considerably with the levels of combined contamination with Legionella and nontuberculous mycobacteria. Legionella spp. were obtained from 61% of the water samples from 24-hour home baths, but only from 3% of the samples from public bathhouses and hot springs. This is despite the fact that a few outbreaks of Legionnaires' disease in Nagano Prefecture as well as other regions of Japan have been traced to bath water contamination. The comparatively higher rate of contamination of the 24-hour home baths is a matter of concern. It is therefore advisable to routinely implement good maintenance of the water basins, particularly of the 24-hour home baths.

Incidence of Legionella and heterotrophic bacteria in household rainwater tanks in Azumino, Nagano prefecture, Japan

Many administrative agencies in Japan are encouraging installation of household rainwater-storage tanks for more effective use of natural rainwater. Water samples were collected periodically from 43 rainwater tanks from 40 households and tested for the presence of Legionella species and the extent of heterotrophic bacteria in Azumino city, Nagano prefecture, Japan. PCR assays indicated the presence of Legionella spp. in 12 (30%) of the 43 tank water samples. Attempts were made to identify correlations between PCR positive samples, topography, pH, chemical oxygen demand (COD), atmospheric temperature and the numbers of heterotrophic bacteria. Between June and October, 2012, the numbers of heterotrophic bacteria in rainwater tanks and the values of COD positively correlated with the presence of Legionella species. In most of the Legionella-positive cases, heterotrophic bacterial cell counts were >10(4) CFU/mL. Moreover, Legionella species were less frequently detected when the COD value was >5 mg KMnO(4)/L. Therefore, at least in Azumino, Japan between June and October 2012, both heterotrophic bacterial counts and COD values may be considered index parameters for the presence of Legionella cells in rainwater tanks. Much more accumulation of such data is needed to verify the accuracy of these findings.

The impact of aerators on water contamination by emerging gram-negative opportunists in at-risk hospital departments

OBJECTIVE

Our aim was to evaluate the impact of aerators on water microbiological contamination in at-risk hospital departments, with a view to quantifying the possible risk of patient exposure to waterborne microorganisms.

DESIGN

We analyzed the microbiological and chemical-physical characteristics of hot and cold water in some critical hospital departments.

SETTING

Two hospitals in northern Italy.

METHODS

We took 304 water samples over a 1-year period, at 3-month intervals, from taps used by healthcare personnel for handwashing, surgical washing, and the washing of medical equipment. We analyzed heterotrophic plate counts (HPCs) at 36°C and 22°C, nonfastidious gram-negative bacteria (GNB-NE), and Legionella pneumophila.

RESULTS

The percentages of positivity and mean values of HPCs at 22°C, HPCs at 36°C, and GNB-NE loads were significantly higher at outlet points than in the plumbing system. In particular, GNB-NE positivity was higher at outlet points than in the plumbing system in both the cold water (31.58% vs 6.58% of samples were positive) and hot water (21.05% vs 3.95%) supplies. Our results also revealed contamination by L. pneumophila both in the plumbing system and at outlet points, with percentages of positive samples varying according to the serogroup examined (serogroups 1 and 2-14). The mean concentrations displayed statistically significant (P < .001) differences between the outlet points (27,382.89 ± 42,245.33 colony-forming units [cfu]/L) and the plumbing system (19,461.84 ± 29,982.11 cfu/L).

CONCLUSIONS

These results reveal a high level of contamination of aerators by various species of gram-negative opportunists that are potentially very dangerous for immunocompromised patients and, therefore, the need to improve the management of these devices.

Epidemiological investigation on a suggestive case of Legionella pneumonia and public health implications

We report a case of Legionella pneumonia in a patient with psoriasis. The clinical strain had an identical PFGE pattern of 1 subtype of L. pneumophila serogroup 1 isolated at low concentration in a sporting club bath. Diagnostic, clinical and epidemiological aspects are discussed for their relevant public health implications.

A Review of the Research Literature on Evidence-Based Healthcare Design

Objective:

This report surveys and evaluates the scientific research on evidence-based healthcare design and extracts its implications for designing better and safer hospitals.

Background:

It builds on a literature review conducted by researchers in 2004.

Methods:

Research teams conducted a new and more exhaustive search for rigorous empirical studies that link the design of hospital physical environments with healthcare outcomes. The review followed a two-step process, including an extensive search for existing literature and a screening of each identified study for the relevance and quality of evidence.

Results:

This review found a growing body of rigorous studies to guide healthcare design, especially with respect to reducing the frequency of hospital-acquired infections. Results are organized according to three general types of outcomes: patient safety, other patient outcomes, and staff outcomes. The findings further support the importance of improving outcomes for a range of design characteristics or interventions, including single-bed rooms rather than multibed rooms, effective ventilation systems, a good acoustic environment, nature distractions and daylight, appropriate lighting, better ergonomic design, acuity-adaptable rooms, and improved floor layouts and work settings. Directions for future research are also identified.

Conclusions:

The state of knowledge of evidence-based healthcare design has grown rapidly in recent years. The evidence indicates that well-designed physical settings play an important role in making hospitals safer and more healing for patients, and better places for staff to work.

[Managing lower respiratory tract infections in immunocompetent patients. Definitions, epidemiology, and diagnostic features]

Les infections respiratoires basses sont une des principales cause de mortalité dans le monde et les pneumopathies représentent en France la première cause de décès d'origine infectieuse. Trois entités nosologiques distinctes sont habituellement isolées en fonction de la localisation infectieuse : la bronchite aiguë, la pneumopathie et la bronchopneumopathie (atteignant les bronches et le parenchyme pulmonaire). En cas d'infections de l'arbre bronchique dans le cadre d'une bronchopathie chronique on parle de décompensation infectieuse de la maladie bronchique. Les deux principales difficultés diagnostiques de ces infections sont de déterminer la présence d'une participation alvéolaire au processus infectieux et de définir l'agent (ou les agents) pathogènes. Ces deux éléments vont conditionner la prise en charge thérapeutique. En dehors de l'examen physique, indispensable dans ce contexte, seule la radiographie thoracique pourra, en cas de persistance d'un doute, permettre de confirmer la présence d'une participation alvéolaire. Le diagnostic microbiologique pose la question de sa nécessité systématique et celui de sa valeur. Il n'est pas indispensable de réaliser un diagnostic microbiologique de certitude dans tous les cas. La décision de documentation doit répondre à deux impératifs : faisabilité et valeur diagnostique. La valeur d'un prélèvement dépend de son aptitude à mettre en évidence l'agent pathogène et dans certains cas de la possibilité d'en déterminer le profil de sensibilité (qui reste une indication majeure à la réalisation de ces prélèvements).