Modification of Bolton Broth by Supplementation of Triclosan for the Isolation of Campylobacter jejuni and Campylobacter coli in Chicken Carcass Rinse

Introduction: Triclosan has been used as an antibiotic supplement on Yersinia and Pseudomonas selective agars and has activity against a broad range of Gram-positive and most Gram-negative organisms. Innate resistance of Campylobacter spp., including C. fetus and C. gracilis, against triclosan has been reported. Given that its mode of action against Gram-negative bacteria differs from that of cephalosporins, triclosan has potential as a selective supplement to inhibit cefoperazone-resistant flora such as ESBL-producing Escherichia coli in cefoperazone-based enrichment broth used for detection of C. jejuni or C. coli.

Purpose: The aim of this study was to compare the detection ability and selectivity of triclosan-supplemented Bolton broth (T-Bolton broth) with normal broth during the isolation of Campylobacter spp. from whole chicken carcass rinses.

Methods: In total, 80 chickens were rinsed with 400 ml buffered peptone water. A 25-ml aliquot of rinsate was combined with 25 ml (blood-free) of 2 × Bolton broth or 2× T-Bolton broth prior to incubation at 42°C for 48h under microaerobic conditions. A loopful of each enrichment culture was then streaked onto mCCDA and incubated at 42°C for another 48h under microaerobic conditions.

Results: We compared the performance of two broths in combination with mCCDA for the isolation of C. jejuni or C. coli from chicken carcass rinse. The number of Campylobacter-positive samples was significantly higher in T-Bolton broth (57/80, 71.3%) than in normal Bolton broth (22/80, 27.5%) (P < 0.05). Furthermore, mCCDA plates prepared from T-Bolton broth samples exhibited much lower levels of contamination (3/80, 3.8%) than in those prepared from normal Bolton broth (60/80, 75.0%) (P < 0.05), indicating the superior selectivity of T-Bolton broth.

Significance: Relative to normal broth, the supplemented broth showed significant improvements in isolation rate and selectivity with respect to the recovery of C. jejuni and C. coli from chicken carcass rinse.