Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures.

Physical and chemical disinfection methods have been proposed with the aim of controlling Legionella water contamination. To date, the most effective procedures for reducing bacterial contamination have not yet been defined. The aim of this study was to assess the long-term effectiveness of various disinfection procedures in order to reduce both culturable and nonculturable (NC) legionellae in different hospital water networks treated with heat, chlorine dioxide, monochloramine, and hydrogen peroxide. The temperature levels and biocide concentrations that proved to give reliable results were analyzed. In order to study the possible effects on the water pipes, we verified the extent of corrosion on experimental coupons after applying each method for 6 months. The percentage of positive points was at its lowest after treatment with monochloramine, followed by chlorine dioxide, hydrogen peroxide, and hyperthermia. Different selections of Legionella spp. were observed, as networks treated with chlorine-based disinfectants were contaminated mainly by Legionella pneumophila serogroup 1, hyperthermia was associated with serogroups 2 to 14, and hydrogen peroxide treatment was associated mainly with non-pneumophila species. NC cells were detected only in heat-treated waters, and also when the temperature was approximately 60°C. The corrosion rates of the coupons were within a satisfactory limit for water networks, but the morphologies differed. We confirm here that chemical disinfection controls Legionella colonization more effectively than hyperthermia does. Monochloramine was the most effective treatment, while hydrogen peroxide may be a promising alternative to chlorine-based disinfectants due to its ability to select for other, less virulent or nonpathogenic species.

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.

Monochloramine and chlorine dioxide for controlling Legionella pneumophila contamination: biocide levels and disinfection by-product formation in hospital water networks.

Legionella colonization in hospital hot water distribution networks was evaluated following 36 months of continuous treatment with monochloramine and compared with chlorine dioxide. Nitrite, nitrate, chlorite, chlorate, bromide, trihalomethanes and haloacetic acids as well as the biocide concentration at sampled points were measured. Only 8/84 samples treated with monochloramine were found contaminated and after the first 8 months of treatment no Legionella was isolated. Chlorine dioxide was associated with a strong reduction in Legionella contamination compared to pre-treatment, but differences according to the device were observed. Monochloramine between 2 and 3 mg l(-1) and chlorine dioxide between 0.50 and 0.70 mg l(-1) were needed to control Legionella colonization. Comparing no- and post-flush samples, a higher frequency of no-flush positive samples was noted using chlorine dioxide, suggesting an increased risk for patients when they open the tap. No increase in chlorite levels and no water nitrification occurred by using monochloramine. Chlorite at levels exceeding the limit requested for drinking water was measured when chlorine dioxide was applied. In conclusion, we highlight that continuous injection of monochloramine should be considered as an effective alternative to chlorine dioxide in controlling legionellae contamination inside hospital water distribution systems.

A culture-proven case of community-acquired legionella pneumonia apparently classified as nosocomial: diagnostic and public health implications.

We report a case of Legionella pneumonia in a 78-year-old patient affected by cerebellar haemangioblastoma continuously hospitalised for 24 days prior to the onset of overt symptoms. According to the established case definition, this woman should have been definitely classified as a nosocomial case (patient spending all of the ten days in hospital before onset of symptoms). Water samples from the oncology ward were negative, notably the patient's room and the oxygen bubbler, and the revision of the case history induced us to verify possible contamination in water samples collected at home. We found that the clinical strain had identical rep-PCR fingerprint of L. pneumophila serogroup 1 isolated at home. The description of this culture-proven case of Legionnaires' disease has major clinical, legal, and public health consequences as the complexity of hospitalised patients poses limitations to the rule-of-thumb surveillance definition of nosocomial pneumonia based on 2-10-day incubation period.

[Hand hygiene of medical and nursing students during clinica rotations: a pilot study on knowledge, attitudes and impact on bacterial contamination]. / Igiene delle mani in studenti di infermieristica e medicina durante i tirocini: studio pilota su conoscenze, comportamenti e impatto sulla contaminazione batterica.

UNLABELLED: Hand hygiene in nursing and medical students during training: a pilot study on knowledge, practices and impact on bacterial contamination. INTRODUCTION: Despite exhaustive guidelines on hand hygiene (HH), compliance in health care professionals is reported to be low. In order to improve adherence with HH, interventions on students' education should be effective. AIM: To describe the knowledge, behavior and hand hygiene (HH) practices in nursing and medical students. The results of the pilot study are presented. METHODS: A questionnaire designed to investigate knowledge on HH and its practical implementation was administered to a sample of 50 nursing and 50 medical students. Data collected were associated with hand contamination measured at the beginning and at the end of the training shift. RESULTS: All nursing students performed HH with a significantly higher frequency compared to medical students. At the end of training, total bacterial counts were significantly reduced in both groups, but more in nursing students. Total bacterial count increased in absence of hygienic practices and the most effective procedure was the alternate use of conventional hand washing and alcohol-based hands rubs. The knowledge of both groups was adequate, although some differences were observed. CONCLUSIONS: At the beginning of their course, nursing students are educated to correct practices that implement during practical training. Medical students receive information on HH later in their education and pay less attention to these aspects, also due to the limited number of physical contacts with patients. Thus, the contents on HH should be anticipated before the start of the training activity.