The Impact of Aerators on Water Contamination in Hospitals
The Impact of Aerators on Water Contamination in Hospitals
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.
Two hospitals in northern Italy.Setting.
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.
The water distribution system in hospitals may constitute a source of healthcare-associated infections (HAIs) caused by opportunistic pathogens such as Pseudomonas aeruginosa, Legionella pneumophila, Stenotrophomonas maltophilia, Burkholderia cepacia, Acinetobacter species, and fungi. These organisms are transmitted by direct contact (eg, hydrotherapy, bathing, and debridement), ingestion of water, indirect contact (eg, improperly reprocessed medical devices), inhalation of aerosols generated by a water source, and aspiration of contaminated water. In particular, P. aeruginosa can persist in hospital water for long periods and can cause nosocomial outbreaks of disease, frequently involving drug-resistant organisms.
Immunocompromised patients are particularly susceptible to infection by such microorganisms, which can cause bacteremia, pneumopathy, meningitis, and other conditions. One of the emerging microorganisms most frequently involved in these pathologies is P. aeruginosa, which is reported to be lethal in 50%, 70%, and 20% of bacteremia, pneumopathy, and meningitis cases, respectively.
The quality of drinking water is subject to many regulations based on lifetime health effects in the general population. However, with regard to people with increased susceptibility to infection, insufficiently broad water quality indicators are used (eg, they do not include opportunistic pathogens), and there is a lack of guidelines covering all the various healthcare settings. Only a few European countries (United Kingdom, France, and Germany) and the US Centers for Disease Control and Prevention (CDC) have drawn up guidelines for water quality in healthcare facilities. The CDC recommendations include strategies to minimize the growth and persistence of gram-negative waterborne bacteria, such as the recommendation that cold water in healthcare facilities should be stored and distributed at temperatures below 20°C and that hot water should be stored above 60°C and circulated with a minimum return temperature of 51°C.
In Germany and France, environmental surveillance of water systems is an integral part of the infection control programs used. The aim of our study was to evaluate the microbiological quality of the water supply in a few critical hospital departments, with a view to quantifying the possible risk of exposure of patients to waterborne opportunistic gram-negative microorganisms and to determining whether this risk is engendered by contamination attributable to the plumbing system or to the use of aerators, an aspect that, to our knowledge, has not yet been investigated.
Abstract and Introduction
Abstract
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.
Two hospitals in northern Italy.Setting.
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.
Introduction
The water distribution system in hospitals may constitute a source of healthcare-associated infections (HAIs) caused by opportunistic pathogens such as Pseudomonas aeruginosa, Legionella pneumophila, Stenotrophomonas maltophilia, Burkholderia cepacia, Acinetobacter species, and fungi. These organisms are transmitted by direct contact (eg, hydrotherapy, bathing, and debridement), ingestion of water, indirect contact (eg, improperly reprocessed medical devices), inhalation of aerosols generated by a water source, and aspiration of contaminated water. In particular, P. aeruginosa can persist in hospital water for long periods and can cause nosocomial outbreaks of disease, frequently involving drug-resistant organisms.
Immunocompromised patients are particularly susceptible to infection by such microorganisms, which can cause bacteremia, pneumopathy, meningitis, and other conditions. One of the emerging microorganisms most frequently involved in these pathologies is P. aeruginosa, which is reported to be lethal in 50%, 70%, and 20% of bacteremia, pneumopathy, and meningitis cases, respectively.
The quality of drinking water is subject to many regulations based on lifetime health effects in the general population. However, with regard to people with increased susceptibility to infection, insufficiently broad water quality indicators are used (eg, they do not include opportunistic pathogens), and there is a lack of guidelines covering all the various healthcare settings. Only a few European countries (United Kingdom, France, and Germany) and the US Centers for Disease Control and Prevention (CDC) have drawn up guidelines for water quality in healthcare facilities. The CDC recommendations include strategies to minimize the growth and persistence of gram-negative waterborne bacteria, such as the recommendation that cold water in healthcare facilities should be stored and distributed at temperatures below 20°C and that hot water should be stored above 60°C and circulated with a minimum return temperature of 51°C.
In Germany and France, environmental surveillance of water systems is an integral part of the infection control programs used. The aim of our study was to evaluate the microbiological quality of the water supply in a few critical hospital departments, with a view to quantifying the possible risk of exposure of patients to waterborne opportunistic gram-negative microorganisms and to determining whether this risk is engendered by contamination attributable to the plumbing system or to the use of aerators, an aspect that, to our knowledge, has not yet been investigated.
