Removal of waterborne pathogens from liver transplant unit water taps in prevention of healthcare-associated infections: a proposal for a cost-effective, proactive infection control strategy

Abstract

Hospital water supplies often contain waterborne pathogens, which can become a reservoir for healthcare-associated infections (HAIs). We surveyed the extent of waterborne pathogen contamination in the water supply of a Liver Transplant Unit. The efficacy of point-of-use (POU) water filters was evaluated by comparative analysis in routine clinical use. Our baseline environmental surveillance showed that Legionella spp. (28%, 38/136), Pseudomonas aeruginosa (8%, 11/136), Mycobacterium spp. (87%, 118/136) and filamentous fungi (50%, 68/136) were isolated from the tap water of the Liver Transplant Unit. 28.9% of Legionella spp.-positive water samples (n = 38) showed high-level Legionella contamination (≥10(3) CFU/L). After installation of the POU water filter, none of these pathogens were found in the POU filtered water samples. Furthermore, colonizations/infections with Gram-negative bacteria determined from patient specimens were reduced by 47% during this period, even if only 27% (3/11) of the distal sites were installed with POU water filters. In conclusion, the presence of waterborne pathogens was common in the water supply of our Liver Transplant Unit. POU water filters effectively eradicated these pathogens from the water supply. Concomitantly, healthcare-associated colonization/infections declined after the POU filters were installed, indicating their potential benefit in reducing waterborne HAIs.

Field evaluation of a new point-of-use faucet filter for preventing exposure to Legionella and other waterborne pathogens in health care facilities

“…This is consistent with 3 previous studies where total bacteria were seen consistently within 14 days of use. 1,6,8 Explanations for the presence of total HPC bacteria have included external contamination of the filter housing or that growth occurred within the filter. Our data suggest an alternative explanation.…”

“…1,2,[4][5][6][7][8] Different models of filters have been shown to be efficient in removing Legionella spp, 1,2,8 P aeruginosa, 4,8 P aeruginosa and S maltophilia, 5 Mycobacterium spp, 6,8 and fungi. 7,8 However, in 6 of these 7 studies, the filters were only rated for 1 1 or 2 weeks of continuous use. [4][5][6][7][8] In addition, flow restriction has been reported to further shorten the duration of use for the filters.…”

“…7,8 However, in 6 of these 7 studies, the filters were only rated for 1 1 or 2 weeks of continuous use. [4][5][6][7][8] In addition, flow restriction has been reported to further shorten the duration of use for the filters. 7 The utility of POU filters as a tool for infection prevention would improve and be less cost prohibitive if the filters maintained efficacy and flow for longer periods of time.…”

Hospital Water and Opportunities for Infection Prevention

“…Over half of cases occurred between June and October, with July and September having the highest and March the lowest prevalence [25]. Others have shown similar results [26]. Other hospital-acquired Gram-negative infections have also been shown to vary seasonally and correlate with humidity [27].…”

“…A liver transplant unit within a 1,600-bed hospital with no internal disinfection system succeeded in eliminating cold-water colony counts of Legionella , mycobacteria and filamentous fungi by installing faucet filters, while control sources without filters continued to grow these organisms. Interestingly, over time, the heterotrophic plate count increased, suggesting splashback from the sink drain or breakthrough contamination of the filters [26]. Williams et al noted similar findings after they installed point-of-use filters in a select handful of faucets in a skilled nursing facility that had experienced an outbreak/pseudo-outbreak of rapidly growing mycobacteria [7].…”