Infection Control & Hospital Epidemiology
1255
Fig. 1. Sink drain cover placed in a sink.
cultures. The water flow was adjusted to a rate typically used for hand hygiene. After evaluation of dispersal of gram-negative bacilli, swabs
inserted through an opening of the strainer were used to sample the proximal sink drain to a depth of 2.5cm (1 inch) below the strainer. The swabs were plated onto MacConkey agar (Hardy Diagnostics, Santa Maria, CA) and incubated at 37°C for 24 hours. The Fisher exact test was used to compare the pro- portions of contamination with versus without the device in place. To assess real-world feasibility of implementing the devices,
we placed the sink drain covers in 20 sinks in patient rooms of a medical intensive care unit for 2 weeks. All drain covers were replaced after the initial 7 days, and individual devices were switched out if they became dislodged or if there was visible discoloration or biofilm. At the end of the study, we cultured the sink bowl and adjacent surfaces after running the water. In addition, the top surface of the devices was cultured for gram- negative bacilli. Nursing and environmental services personnel were interviewed regarding whether the devices caused disruption in normal care activities.
Results
The sink drain cover required ~15 seconds to install or remove. The device fit on all types of sinks tested and did not reduce water outflow. The drain cover was effective in preventing dispersal of fluorescent gel to countertops or other adjacent surfaces (0 of 30 [0%] vs 8 of 30 [27%] dispersal; P=.005). There was evidence of splashing of fluorescent gel from the drain to the bottom surface of the drain cover, but no dispersal was noted outside the cover. Of 74 sinks cultured, 72 (97%) had gram-negative bacilli
recovered from swabs inserted below the strainer. As shown in Fig. 2, the device prevented dispersal of colonizing gram-negative bacilli to the sink bowl and to surfaces adjacent to the bowl. All control cultures collected after disinfection but before running the water were negative. During the 2-week period when the drain covers were installed
in the medical intensive care unit, there were no reports of inconvenience to personnel or patients. Of the 20 drain covers, 1 (5%) was dislodged during cleaning requiring reattachment. On the final day of the drain cover placement, only 1 of the 20 (5%) devices had gram-negative bacilli recovered from the top surface, but the number of colonies was low (≤8 colony-forming units).
Fig. 2 . Percentage of sink bowls and surfaces outside the bowls with positive cultures for gram-negative bacilli after running the water for 30 seconds. Surfaces outside the bowls included countertops, sink edges, or other surfaces ≤15.25cm (≤6 inches) outside the sink bowl. *, P≤.01.
No dispersal of gram-negative bacilli occurred when the water was run for 30 seconds.
DISCUSSION
In our facility, 97% of sink drains were colonized with gram- negative bacilli, and running water resulted in frequent dispersal to the sinkbowlandsurfaces outside the bowl.Anovel sink drain cover was effective in preventing dispersal of gram-negative bacilli and a fluorescent gel. In a 2-week trial in an intensive care unit, most devices remained in place without substantial contamination of the exposed top surface, and there was no dispersal of gram-negative bacilli from sinks with the devices in place for 7 days. Our findings suggest that the sink drain covers could provide a
simple means to reduce dissemination of pathogens from con- taminated sinks. Many alternative approaches that have been used to control outbreaks related to sinks may be costly or labor intensive. Such interventions include changing sink designs, pla- cing barriers between sinks and work areas, replacing drainage systems, use of devices to disinfect P-traps, and complete elim- ination of sinks.1–3,6–10 Our study has some limitations. The study was conducted in 1
hospital. Although the device was effective for all sink designs in the facility, it is possible that modifications may be required to fit some designs used in other facilities. We only implemented the devices for a 2-week period in an intensive care unit, and we cannot exclude the possibility that limitations of the device were missed due to the short study period. Although we changed out the devices after 1 week during our trial, it is possible that less frequent changes may be required. Thus, further studies are needed including randomized trials to determine the effectiveness of the devices in preventing colonization and infection with sink- associated pathogens in healthcare facilities.
Acknowledgments. We would like to thank the staff of the medical intensive care unit at the Louis Stokes Cleveland VA Medical Center for assistance with the trial of the devices.
Financial support. This work was supported by the Department of Veterans Affairs and by a grant from Boehringer Laboratories to C.J.D.
Conflicts of interest. C.J.D. has received research funding from Clorox, EcoLab, GOJO, Pfizer, Avery Dennison, and Boehringer Laboratories. All authors report no conflicts of interest relevant to this article.
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