Although the amounts of money and time associated with using shoe covers or other means to prevent floor contamination in animal research facilities can be substantial, the most effective policies and practices remain unknown. In this study, the authors subjected six occupied rodent holding rooms in their animal research facility to three conditions: use of disinfectant mats; use of shoe covers; and no disinfectant mats or shoe covers. The authors took bacterial culture samples from the rooms under each condition. There was no significant difference in the mean number of colony forming units (CFUs) cultured when the disinfectant mats or shoe covers were used. However, the mean number of CFUs obtained was significantly lower when either disinfectant mats or shoe covers were used than when neither was used. These results suggest that using disinfectant mats or disposable shoe covers may reduce the bacterial load on rodent holding room floors.

The authors evaluated the effectiveness of adhesive mats, contamination control flooring, and shoe covers in decreasing the presence of microbial agents on animal holding room floors and footwear. Swab samples taken from animal holding room floors after the use of each product were compared with samples taken from rooms after no products were used. Swab samples were also taken from the heels and soles of the footwear of animal care staff before and after use of each product. The use of contamination control flooring or shoe covers significantly reduced the amount of organic material (as indicated by ATP levels measured by a luminometer) present on floors. Bacterial and ATP contamination of footwear was significantly lower after the use of shoe covers than after the use of adhesive mats or contamination control flooring, and the use of shoe covers led to a greater decrease in contamination before and after use than did use of either of the other two products. Although shoe covers were superior to both adhesive mats and contamination control flooring for decreasing contamination of animal room floors and footwear, facilities must take into account the contamination control standards required, the cost of the product, and the labor and time associated with product use when deciding which contamination control practices to implement.

According to the 8th edition of the Guide for the Care and Use of Laboratory Animals (the Guide), rodent cage accessories,such as filter tops, should be sanitized at least once every 2 wk. We performed a study to test the hypothesis that organic contamination(measured by ATP content, expressed as relative light units (RLU)) of cage accessories (wire bar inserts and filter top lids) does not differ at 2 wk (14 d) as compared with 30, 60, and 90-d time points after cage change even when in constant use. An additional time point for filter top lids of 180 d after cage change was also evaluated. Eight groups were studied: the wire bar inserts and filter top lids used for mice and rats, in both static and individually ventilated cages (IVC). When analyzing data from both mouse and rat static and IVC caging, we found that the mean RLU values for mouse IVC and rat static and IVC cage components were below 100,000 RLU at the 14-d time point. The mean value for the mouse static groupwas slightly above 100,000 RLU at this time point. Based on this observation, we considered 100,000 RLU to be an appropriate actionable level. We concluded that changing wire bar inserts at least every 14 d, as recommended in the Guide for sanitizing these components in mouse and rat static cages, may be considered acceptable. This interval could be extended for mouse and rat IVC cages up to 90 d while remaining below this limit. Filter top lids for mouse static cages should be changed at least every 30 d, but static rat and IVC mouse/rat filter top lids could be changed up to every 180 d, while still staying below this actionable level of contamination.