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Occurrence of Non-Tuberculous Mycobacteria at an Acute Care Hospital Using Secondary Drinking Water Treatment
Citation:
Pfaller, S., C. White, D. King, AND D. Lytle. Occurrence of Non-Tuberculous Mycobacteria at an Acute Care Hospital Using Secondary Drinking Water Treatment. Water Quality Technology Conference, Indianapolis, IN, November 13 - 17, 2016.
Impact/Purpose:
The goal of this study was to determine the long-term effect of secondary chloramine treatment on the occurrence of non-tuberculous mycobacteria (NTM) at a 300-bed acute care hospital. The results will inform stakeholders about the need for long-term monitoring for pathogenic microorganisms after addition of secondary treatment using knowledge of the acute care facilities' building hydrology and in locations housing sensitive patient populations.
Description:
The development of infection control strategies at acute-care hospitals has contributed to an overall decline in the number of healthcare-associated infections (HAI’s) in the United States, especially those caused by contaminated equipment used in surgical procedures and contaminated medical devices. However the proportion of HAI’s arising from patient exposure to contaminated water in acute-care hospitals is unknown. Waterborne bacteria responsible for HAI’s include Psuedomonas aeruginosa, Legionella pneumophila, Acinetobacter species, and non-tuberculous mycobacteria (NTM), among others, and outbreaks of illness caused by these bacteria are on the rise. To reduce or prevent waterborne HAI’s, hospitals have begun using a variety of drinking water disinfection technologies to secondarily treat water entering the hospital, including chlorine dioxide, chloramine, and copper-silver ionization technologies. Little is known about the effectiveness of these technologies for controlling waterborne pathogens long-term. The goal of this study was to determine the long-term effect of secondary chloramine treatment on the occurrence of NTM at a 300-bed acute care hospital. Water samples were collected at 16 taps located throughout the hospital once a month for six months before and six months after a chloramine disinfection system was installed. Samples were analyzed for the presence of NTM using a standard culture method. NTM were never detected (before or after addition of chloramine treatment) at 25 % (4/16) of sites. Twenty-five % (4/16) sites had sporadic NTM detections before addition of chloramine treatment but NTM were reduced below detection limits after addition of secondary treatment. Fourty-four % (7/16) of sites had persistent detections of NTM before addition of secondary treatment, no detections for approximately three months after addition of chloramine, but sporadic detections three months after addition of secondary treatment, suggesting possible recolonization at or near these sites. NTM were detected continuously at one site during the entire 12 months of the study, and at relatively high levels (>400 colony forming units/ 200 ml water sampled). Various clinically relevant species of NTM were isolated from sites with NTM detections before and after addition of chloramine treatment. These data suggest that secondary disinfection with chloramine can be effective at reducing NTM below detection limits at certain locations within an acute-care hospital, but not all. A good understanding of the hospital’s hydrological systems, combined with microbiological monitoring at sites housing sensitive patient populations, will continue to be necessary to control HAI’s caused by NTM and other waterborne pathogens, even with addition of secondary treatment technologies.
URLs/Downloads:
https://www.awwa.org/conferences-education/conferences/water-quality-technology/water-quality-program.aspx