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Submitted to: Natural Resources Research Update (NRRU)
Publication Type: Research Technical Update Publication Acceptance Date: 4/7/2010 Publication Date: 4/7/2010 Citation: Cook, K.L. 2010. Survival of the Causative Agent of Johne’s Disease (Mycobacterium avium subsp. paratuberculosis) in Biofilms on Trough Materials. Natural Resources Research Update (NRRU). Update #1. Interpretive Summary: Technical Abstract: The continued global increase in the number of cases of Johne’s disease among dairy cattle suggests that there remain hidden sources of contamination in the farm environment where susceptible animals may be routinely exposed to Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of the disease. Livestock watering troughs are frequented by all animals on a farm, they provide a moist, nutrient rich environment for bacterial survival and the trough basin provides a surface for bacterial adhesion (i.e., biofilm formation). MAP has been shown to have a very hydrophic cell wall structure (as do most Mycobacterium sp.) which increases its propensity for biofilm formation (Bolster, 2009). A study evaluated the ability of MAP to form mixed-community biofilms on the four most commonly used watering trough materials (concrete, plastic, stainless steel and galvanized steel), to persist amid the trough water microbial flora and to become incorporated into an established biofilm on the same trough materials (Cook, 2010a). High concentrations of MAP were detected in biofilms on all trough materials within three days of inoculation into trough water and it survived in the biofilms for over 149 days. Trough material composition influenced the survival of MAP with the lowest survival exhibited on stainless steel, followed by plastic, galvanized steel and concrete. To evaluate the effect of chlorine disinfection on survival of MAP in the trough biofilms, 2ppm chlorine was added to trough water on a weekly basis. Chlorination was found to reduce survival of the organism on stainless and galvanized steel trough materials, but not on concrete or plastic materials (Cook, 2010b). Chlorination may have been effected by higher pH in tanks with concrete trough materials and lower total and free chlorine availability in tanks with plastic trough materials. These results suggest that the effectiveness of chlorine disinfection depends on trough material construction, pH and chlorine availability. Control of pathogens such as MAP in livestock drinking water sources may serve as a critical control point for slowing spread of the disease. Optimization of disinfection protocols and elimination of biofilms on trough surfaces should reduce persistence of MAP in trough waters. To inhibit spread of this organism and exposure of susceptible animals to MAP on infected farms, best management practices aimed at maintaining biofilm-free trough surfaces should be included in any Johne’s control plan. Publications contributing to the NRRU Release as shown above: Bolster, C.B., Cook, K.L., Haznedaroglu B., Walter, S. 2009. The Transport of Mycobacterium avium subsp. paratuberculosis through Saturated Aquifer Materials. Letters in Applied Microbiology. 48:307-312 Cook, K.L., Britt, J.S., Bolster, C.B. 2010a. Survival of Mycobacterium avium subsp. paratuberculosis in biofilms on livestock watering trough materials Vet. Micro. 141:103-109 Cook, K.L., Bolster, C.B., Britt, J.S., Rothrock, M. 2010b. Effect of watering trough chlorination on persistence of Mycobacterium avium subsp paratuberculosis. Bovine Practitioner. 44:69-76. |
