Evaluation of the Efficacy of Disinfectant Footmats for the Reduction of Bacterial Contamination on Footwear in a Large Animal Veterinary Hospital.

BACKGROUND: Infection control is critical to providing high-quality patient care. Many veterinary teaching hospitals (VTHs) utilize footbaths or footmats at entrances and key control points throughout the facility to decrease trafficking of pathogenic microorganism on contaminated footwear. HYPOTHESIS/OBJECTIVES: To compare efficacy of 4 disinfectants used in footmats for decreasing bacterial contamination of footwear in a large animal hospital. ANIMALS: A single adult dairy cow was housed in a stall for 4 days to facilitate stall contamination with fecal material. METHODS: Overboots were experimentally contaminated with organic material in a standardized manner. Each boot was randomly assigned to 1 of 5 treatments (no treatment, or exposure to 1 of 4 disinfectants: an accelerated peroxygen [AHP], a peroxygen [VIRKON], a quaternary ammonium [QUAT], and a phenolic disinfectant [PHENOLIC]) by stepping on a soaked footmat and collecting samples from boot soles. Generalized linear modeling was used to analyze differences in bacterial counts. RESULTS: Reductions in colony-forming units (CFUs) on treated boots ranged from no detectable reduction to 0.45 log10 and varied by disinfectant. Percentage reductions in total bacterial counts generally were larger (albeit still modest) for AHP and QUAT disinfectants (range 37-45%) and smallest for the PHENOLIC (no detectable reduction). CONCLUSIONS AND CLINICAL IMPORTANCE: In general, use of disinfectant footmats was associated with significant reductions in viable bacteria on overboots-albeit with variable efficacy. Footmats may be useful adjuncts to cleaning and disinfection programs for decreasing trafficking of microorganisms throughout VTHs but should not be considered as a sole prevention method.

Detection of different serotypes of Salmonella enterica in experimentally inoculated equine fecal samples by commercially available rapid tests.

BACKGROUND: Salmonella enterica can significantly impact management of animal facilities. Comprehensive screening is essential for effective control in high-risk populations. Availability of reliable point-of-care diagnostic tests would facilitate these efforts. HYPOTHESIS/OBJECTIVES: Compare the ability of commercially available rapid diagnostic assays (2 lateral flow immunoassays [LFIs], DNA hybridization [DNAH], real-time PCR [qPCR]), and culture to detect common serotypes of S. enterica in feces. ANIMALS: n/a. METHODS: In an experimental study, 112 S. enterica isolates were randomly selected from the 10 most common serotypes recovered at a veterinary hospital. Archived isolates were amplified in broth and standardized inocula (100 colony forming units) were incubated with equine feces in tetrathionate broth (TET). Cultures were tested in a blinded fashion by using LFIs, DNAH, qPCR, and culture. RESULTS: The LFIs detected 84% and 67% of isolates, respectively, but reactivity varied among serotypes. Both reacted poorly with serotype Cerro (Group K) isolates, and 1 LFI did not react with any serotype Mbandaka (Group C1) or Montevideo (Group C1) isolates. DNAH detected 94% of isolates, whereas culture and qPCR most reliably detected all serotypes. False-positive results were obtained for 4 negative controls by using DNAH and 1 negative control by using qPCR, but LFIs and culture had no false-positive results. CONCLUSIONS AND CLINICAL IMPORTANCE: Culture, qPCR, and DNAH were effective in detecting most Salmonella isolates, but have limited application at point-of-care settings. LFIs are appealing as point-of-care tests because of low cost and ease of use, but limited detection of some serotypes needs to be evaluated with samples obtained from naturally infected animals.