Survival of Campylobacter jejuni in biofilms isolated from chicken houses

Campylobacter jejuni is a thermophilic and microaerophilic enteric pathogen associated with poultry. Biofilms may be a source of C. jejuni in poultry house water systems since they can protect constituent microorganisms from environmental stress. In this study. the viability of C. jejuni in biofilms of gram-positive chicken house isolates (P1. Y1, and W1) and a Pseudomonas sp. was determined using a cultural method (modified brucella agar) and direct viable count (DVC). Two-day biofilms grown on polyvinyl chloride (PVC) coupons in R2A broth at 12 and 23degreesC were incubated with C. jejuni for a 6-h attachment period. Media were then refreshed every 24 h for 7 days to allow biofilm growth. Two-day biofilms of PI, Y1, and Pseudomonas spp. enhanced attachment (P < 0.01) of C. jejuni (4.74, 4.62, and 4.78 log cells/cm(2), respectively) compared to W1 and controls without preexisting biofilm (4.31 and 4.22 log cells/cm2, respectively). On day 7, isolates PI and Y1 and Pseudomonas biofilms covered 5.4. 7.0. and 21.5% of the surface. respectively. compared to 4.9% by W1. Viable C. jejuni on the surface decreased (P < 0.05) with time. with the greatest reduction Occurring on surfaces without a preexisting biofilm. The number of viable C. jejuni determined by DVC was greater than that determined by the cultural method, indicating that C. jejuni may form a viable but nonculturable state within the biofilm. Both DVC and the cultural method indicate that biofilms enhance (P < 0.01) the survival of C. jejuni during incubation at 12 and 23degreesC over a 7-day period.