Abstract

1. PVC Baffle Control Faucet Test Faucet From model plumbing system To model plumbing system 101 Yusen Eason Lin, PhD, MBA Graduate Institute of Environmental Education National Kaohsiung Normal University 62 Shen-chong Road, Yanchau Kaohsiung Hsien, Taiwan TEL: +8867-6051036 FAX: +8867-6051379 Email: easonlin@nknucc.nknu.edu.tw http://microlab.nknu.edu.tw Efficacy of Efficacy of Point-of-Use Water Filter in Removing Nosocomial Infection-Associated Waterborne Pathogens in a Laboratory Model Plumbing System Yusen E. Lin1, Hsiu-Yun Shih1, Janet E. Stout2 National Kaohsiung Normal University, Kaohsiung1, TAIWAN, and University of Pittsburgh, Pittsburgh, PA, USA2 Abstract Background: The presence of waterborne pathogens in hospital water systems has been epidemiologically linked to nosocomial infections in Intensive Care Units (ICUs). Nosocomial infections associated with these pathogens increase patient mortality and healthcare cost. Disinfection of hospital water systems has been an alternative in prevention of nosocomial infections. Hyperchlorination, copper-silver ionization and chlorine dioxide have been implemented for control of Legionella in hospital water systems. However, the capital expenditures for treating the entire hospital potable water system may not be cost effective if the risk of nosocomial infection is limited to critical high risk areas (eg. ICUs). Objective: To evaluate the efficacy of a new water filter for removing waterborne pathogens in a laboratory model plumbing system. Methods: Two counter-top goose neck faucets (Figures 1-3) were attached to a laboratory model plumbing system. A 0.005 μm point-of-use filter (Nephros Inc., New York) was attached to a test faucet. Environmental isolates of Legionella, Pseudomonas, Stenotrophomonas, Acinetobacter, Klebsiella, and Mycobacterium were added to the model plumbing system to reach the starting bacterial concentration for each organism at above 3x103 cfu/mL. Water and swab samples were withdrawn at T = 1, 2, 3, 4, 5, 7 and 14 day from the both test faucet (after filtration) and control faucet (no filtration). A standardized microbiological method was followed for cultures of each organism. Results: During the 14-day study, more than 30,000 liters of water was filtered through the filter. Results showed that the point-of-use filter successfully removed L. pneumophila, P. aeruginosa, S. maltophilia, A. baumannii, K. pneumoniae, and M. abcessens from the model plumbing system. No test pathogens were cultured in both water and swab samples from the test faucet. Approximately 2,500,000 cfu/mL of test pathogens, in average, were recovered from the control faucet (Figures 4-9). Unlike chemical water treatment, water filters offer safe drinking water treatment without toxic disinfectants released into water and potential resistance development. Conclusion:Point-of-use water filter may be a cost effective method to control waterborne pathogens in critical area (e.g. ICUs) without systematic disinfection in a large hospital water system. • Introduction • The presence of waterborne pathogens in hospital water systems has been epidemiologically linked to nosocomial infections in Intensive Care Units (ICUs). • The capital expenditures for disinfecting the entire hospital potable water system may not be cost effective if the risk of nosocomial infection is limited to critical high risk areas (eg. ICUs). • Point-of-use filter (POU) has been documented to effectively control Pseudomonas and Legionella species. However, the filters may have to be replaced frequently due to blockage caused by high suspended solids, thus increasing the cost of filter replacement. Figures 4-9. No test organisms were recovered from filtered water (Unit: cfu/mL) Table 1. Concentration of Pathogens in Biofilm Samples from Test (Filtered Water) and Control (Non-Filtered Water) Faucets (Unit: cfu/swab) • Materials and Methods • A model plumbing system was used with two counter-top goose neck faucets installed. A 0.005 um filter cartridge was installed at the test faucet (Figures 1-3) • The experiment was performed for 14 days at total water volume of 30,240 liters (3.6 (L/min) x 60 (min/hr) x 10 (hr/day) x 14 days), which represents more than 7.5 months of filter use @ 4,000 L/month • Environmental isolates of L. pneumophila, P. aeruginosa, S. maltophilia, A. baumannii, K. pneumoniae, and M. abcessens were selected as the test organisms. • Water and biofilm sample were withdrawn at T = 1, 2, 3, 4, 5, 7 and 14 day from the both test and control faucet (no filtration). The standard microbiological method was followed for sample processing. • Results • No bacterium was recovered in water samples from the test faucet which the water was filtered by Nephros filter. Approximately 2,500,000 cfu/mL of bacteria, in average, were recovered from the control faucet (Figure 4-9) • No bacterium colonization was found in the test faucet from biofilm samples. However, colonization was observed in the control faucet (Table 1). Test Control Sponsored by