Potable water and nosocomial Legionnaires' disease--check water from all rooms in which patient has stayed

Presence and Chromosomal Subtyping ofLegionellaSpecies in Potable Water Systems in 20 Hospitals of Catalonia, Spain

Objective:

To investigate the presence and clonal distribution ofLegionellaspecies in the water supply of 20 hospitals in Catalonia, Spain.

Setting:

20 hospitals in Catalonia, an area of 32,000 km2, located in northeast Spain.

Methods:

Environmental cultures of 186 points of potable water supply and 10 cooling towers were performed for the presence ofLegionellaspecies. Following filtration and acid treatment, the samples were seeded in selective MWY (modified Wadowsky Yee)-buffered charcoal yeast extract-a agar. All isolates obtained were characterized microbiologically and genotyped bySfilpulsed-field gel electrophoresis (PFGE).

Results:

73 of 196 water samples, representing 17 of the 20 hospitals included in the study, were positive forLegionella pneumophila(serogroups 1, 2-14, or both). The degree of contamination ranged from 200 to 74,250 colony-forming units/L. Twenty-five chromosomal DNA subtypes were detected by PFGE. A single DNA subtype was identified in 10 hospitals, 2 DNA subtypes were observed in 6 hospitals, and 1 hospital exhibited 3 different DNA subtypes. Each hospital had its ownLegionellaDNA subtype, which was not shared with any other hospitals.

Conclusions:

Legionellawas present in the water of most of the hospitals studied; each such hospital had a unique, dominant chromosomal DNA subtype. The verification of several genomic DNA restriction profiles in such a small geographic area demonstrates the great genetic diversity ofLegionellain the aquatic environment.

Aetiology, source and prevention of waterborne healthcare-associated infections: a review

The purpose of this review is to discuss the scientific literature on waterborne healthcare-associated infections (HCAIs) published from 1990 to 2012. The review focuses on aquatic bacteria and describes both outbreaks and single cases in relation to patient characteristics, the settings and contaminated sources. An overview of diagnostic methods and environmental investigations is summarized in order to provide guidance for future case investigations. Lastly, on the basis of the prevention and control measures adopted, information and recommendations are given. A total of 125 reports were included, 41 describing hospitalized children. All cases were sustained by opportunistic pathogens, mainly Legionellaceae, Pseudomonadaceae and Burkholderiaceae. Hot-water distribution systems were the primary source of legionnaires’ disease, bottled water was mainly colonized by Pseudomonaceae, and Burkholderiaceae were the leading cause of distilled and sterile water contamination. The intensive care unit was the most frequently involved setting, but patient characteristics were the main risk factor, independent of the ward. As it is difficult to avoid water contamination by microbes and disinfection treatments may be insufficient to control the risk of infection, a proactive preventive plan should be put in place. Nursing staff should pay special attention to children and immunosuppressed patients in terms of tap-water exposure and also their personal hygiene, and should regularly use sterile water for rinsing/cleaning devices.

The public health implications of a sporadic case of culture-proven Legionnaires' disease

Legionella pneumophila is an important cause of community-acquired pneumonia. Domestic sources of infection have been increasingly recognised among community-acquired cases. This report summarises the public health investigations and management of a single community-acquired case of Legionnaires' disease in Queensland, commenced in the context of a suspected outbreak. Legionellae from the case's domestic water supply were indistinguishable from the clinical isolate. The implications for future investigation of sporadic cases are discussed.

Legionella pneumonia associated with adult respiratory distress syndrome caused by Legionella pneumophila serogroup 3

A 68-year-old man developed pneumonia 2 days after nearly drowning in a bathtub of a hot spring spa. Chest radiography revealed bilateral consolidation shadows associated with adult respiratory distress syndrome. Initial treatment with antibiotics and pulse therapy with methylprednisolone was not effective. The patient died on the 4th hospital day. A urinary antigen test for Legionella was positive. Legionella pneumophila serogroup 3 was recovered from an intratracheal specimen. The same serotype of Legionella was isolated from the hot spring water. Restriction enzyme analysis by pulse-field gel electrophoresis revealed identical restriction fragments. We conclude that the water at the hot spring spa could have been the source of infection.

Presence and chromosomal subtyping of Legionella species in potable water systems in 20 hospitals of Catalonia, Spain

OBJECTIVE

To investigate the presence and clonal distribution of Legionella species in the water supply of 20 hospitals in Catalonia, Spain.

SETTING

20 hospitals in Catalonia, an area of 32,000 km2, located in northeast Spain.

METHODS

Environmental cultures of 186 points of potable water supply and 10 cooling towers were performed for the presence of Legionella species. Following filtration and acid treatment, the samples were seeded in selective MWY (modified Wadowsky Yee)-buffered charcoal yeast extract-alpha agar. All isolates obtained were characterized microbiologically and genotyped by SfiI pulsed-field gel electrophoresis (PFGE).

RESULTS

73 of 196 water samples, representing 17 of the 20 hospitals included in the study, were positive for Legionella pneumophila (serogroups 1, 2-14, or both). The degree of contamination ranged from 200 to 74,250 colony-forming units/L. Twenty-five chromosomal DNA subtypes were detected by PFGE. A single DNA subtype was identified in 10 hospitals, 2 DNA subtypes were observed in 6 hospitals, and 1 hospital exhibited 3 different DNA subtypes. Each hospital had its own Legionella DNA subtype, which was not shared with any other hospitals.

CONCLUSIONS

Legionella was present in the water of most of the hospitals studied; each such hospital had a unique, dominant chromosomal DNA subtype. The verification of several genomic DNA restriction profiles in such a small geographic area demonstrates the great genetic diversity of Legionella in the aquatic environment.

Comparative analysis of infrequent-restriction-site PCR and pulsed-field gel electrophoresis for epidemiological typing of Legionella pneumophila serogroup 1 strains

Two methods were compared for the analysis of 48 unrelated and epidemiologically related Legionella pneumophila serogroup 1 isolates. These are the infrequent-restriction-site PCR (IRS-PCR) assay with adapters designed for XbaI and PstI restriction sites and the pulsed-field gel electrophoresis (PFGE) analysis determined after DNA restriction with SfiI. Both methods demonstrated a high level of discrimination with a similar capacity for differentiating 23 of the 24 unrelated isolates. PFGE analysis and IRS-PCR assay were both able to identify epidemiologically related isolates of L. pneumophila from three outbreaks. Hence, IRS-PCR assay appears to be a reproducible (intergel reproducibility, 100%) and discriminative (discriminatory index, > or = 0.996) tool for typing of Legionella. Compared to PFGE, however, IRS-PCR presented an advantage through ease of performance and with attributes of rapidity and sensitivity of target DNA.

Community-acquired Legionnaires' disease following minimal exposure to a contaminated source

A case of community-acquired Legionnaires' disease (LD) is described. The source of infection was traced to a push-on tap at the end of a long spur from the hot circulation system in a large old residential building which had been unoccupied for several weeks. Legionella pneumophila serogroup 1 subgroup Pontiac was isolated from the patient's sputum and from the contaminated water supply. Isolates were shown to be indistinguishable from one another when subtyped by pulsed field gel electrophoresis of chromosomal DNA.

Uses of inorganic hypochlorite (bleach) in health-care facilities

Hypochlorite has been used as a disinfectant for more than 100 years. It has many of the properties of an ideal disinfectant, including a broad antimicrobial activity, rapid bactericidal action, reasonable persistence in treated potable water, ease of use, solubility in water, relative stability, relative nontoxicity at use concentrations, no poisonous residuals, no color, no staining, and low cost. The active species is undissociated hypochlorous acid (HOCl). Hypochlorites are lethal to most microbes, although viruses and vegetative bacteria are more susceptible than endospore-forming bacteria, fungi, and protozoa. Activity is reduced by the presence of heavy metal ions, a biofilm, organic material, low temperature, low pH, or UV radiation. Clinical uses in health-care facilities include hyperchlorination of potable water to prevent Legionella colonization, chlorination of water distribution systems used in hemodialysis centers, cleaning of environmental surfaces, disinfection of laundry, local use to decontaminate blood spills, disinfection of equipment, decontamination of medical waste prior to disposal, and dental therapy. Despite the increasing availability of other disinfectants, hypochlorites continue to find wide use in hospitals.