Water sampled from the well, which is the starting point of the drinking water system for the broilers, appeared to be pathogen-free. However in the drinking water system itself the presence of a biofilm was discovered. Biofilms are sessile communities of microorganisms, surrounded by a matrix of self-produced extracellular polymeric substances. Microorganisms present in the biofilm are farm specific, but in many cases Stenotrophomonas maltophilia, Pseudomonas geniculate and Pseudomonas aeruginosa are identified. Also Campylobacter spp., E. coli, Salmonella spp., etc. are biofilm-forming organisms that are often found in bovine drinking water systems.
The drinking water system of broilers is an ideal environment for the formation of a biofilm due to a couple of reasons: slow water flow, high ambient temperatures and the carrier substances of medicines and additives such as vitamins that are administered via the water. These can serve as a source of nutrients for the microorganisms. Besides the health risk of the pathogens present in the biofilm, medicine particles can be captured in the matrix of the biofilm as well. This can lead to underdosing the animals posing a risk for their health and there above resistant strains can develop. Also, the taste and the smell can be influenced negatively.