1468 The characteristics of the sinks were recorded, including depth
of the sink bowl (ie, vertical distance from the strainer to the sink edge), circumference of the bowl, location of the faucet relative to the strainer (ie, directly over the strainer versus offset), automatic versus manual operation, and type of faucet (goose neck versus other). A multivariable logistic model was used to identify factors associated with dispersal of the fluorescent gel. The χ2 test was used to compare categorical variables and the Mann-Whitney U test was used for continuous variables. To assess for collinearity among our model variables, we examined the variance inflation factor. For a subset of 3 sinks that dispersed the fluorescent gel, we examined the impact of different rates of water flow on dispersal.
Results
Overall, 194 sets of sink cultures were obtained from the 4 study hospitals (range, 45–50): 138 in patient rooms and 56 in per- sonnel work areas. Figure 1 shows the percentages of cultures positive for fluoroquinolone-resistant gram-negative bacilli over- all and for each hospital for the sink bowl and the adjacent countertop or other surfaces ≤15.25cm (≤6 inches) from the bowl before disinfection (A) and after disinfection followed by running the water for 30 seconds (B). Cultures of the sink bowl and adjacent areas after disinfection but before running the water were consistently negative, as were cultures of water from faucets. All swabs obtained from the drain of sinks that dispersed fluoroquinolone-resistant gram-negative bacilli were positive for fluoroquinolone-resistant gram-negative bacilli. A subset of 171 consecutive sinks were included in the eva-
luation of dispersal of fluorescent gel. Of the 171 sinks, 137 (80%) were manually operated, 34 (20%) were automated, 117 (68%) had faucets offset from the strainer, 54 (32%) had faucets that delivered water directly onto the strainer, and 150 (88%) had goose-neck–style faucets. The median bowl depth was 19cm (range, 12–31 cm). Of the 171 sinks tested, 67 (39%) dispersed fluorescent tracer
outside the sink bowl. In the multivariable logistic model, the only factor significantly associated with dispersal of fluorescent gel outside the sink bowl was the sink bowl depth (P=.02) (Table 1). Dispersal occurred frequently when the bowl depth was ≤19cm and rarely when the depth was >19cm (64 of 133 [48%] vs 3 of 38 [8%]; P<.001). Dispersal occurred as frequently in sinks in which the faucet was offset from the drain as in those positioned such that water flowed directly onto the strainer (44 of 118 [37%] vs 24 of 54 [44%]; P >.05). The variance inflation factor was <1.5 for all variables. For each of the 3 sinks used to assess the effect of water flow
rate on dispersal, we found that increased flow rate increased the frequency of dispersal. At a flow rate of <200 mL/s, no dispersal occurred from any of the sinks. However, when the flow rate was 260 mL/s or higher, dispersal was consistently demonstrated.
Discussion
Many recent studies have demonstrated the potential for colo- nized sinks to disperse pathogens.1–4 For example, Hota et al3 controlled an outbreak of multidrug-resistant P. aeruginosa linked to sinks by implementing changes to reduce dispersal including
Fig. 1. Frequency of recovery of fluoroquinolone-resistant gram-negative bacilli from sink bowls and countertops at baseline (A) and after running the hot- and cold-water faucets for 30 seconds (B). The sink bowl and countertop were disinfected after the baseline cultures but before running the water.
Scott A. Gestrich et al
Table 1. Odds Ratios for Sink Design Features Associated with Dispersal of Fluorescent Gel from the Sink Drain by Running Water
Characteristic Bowl depth (cm)a
Faucet flow indirect versus direct relative to strainer
Odds Ratio
0.69 1.28
Faucet goose neck versus other design 0.78 Automatic versus manual sink Bowl circumference (cm)
aVertical distance from the strainer to the sink edge.
reducing the water flow pressure and installing barriers between sinks and adjacent preparatory areas. However, limited infor- mation is available on the design of sinks currently used in hos- pitals and on design features associated with pathogen dispersal. In 4 hospitals, we demonstrated that running water resulted in frequent dispersal of fluorescent gel and colonizing fluoroquinolone-resistant gram-negative bacilli from sink drains to sink bowls and surfaces outside the bowl. The one design feature that was significantly associated with dispersal of fluor- escent gel was the sink bowl depth: shallow bowls were more likely to disperse the fluorescent gel. Our findings suggest that modifications in sink design could substantially reduce the risk for dissemination of colonizing pathogens. In the study hospitals, 78% of sinks had relatively shallow bowl depths (ie, ≤19 cm) that were associated with dis- persal of fluorescent gel. Modified designs with deeper sink bowls could reduce dispersal. It is plausible that having the faucet offset from the sink strainer might reduce dispersal. However, we did not find that sinks with offset faucets had significantly lower dispersal of fluorescent gel, suggesting that this modification alone is not sufficient to prevent pathogen dispersal. Finally,
95% Confidence Interval
0.59–0.79 0.58–2.88
0.73 1.01
0.29–2.10 0.30–1.74 0.99–1.04
P
Value .00 .54
.62 .48 .33
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124
