Improvement of Karmali Agar by Supplementation with Tazobactam for Detecting Campylobacter from Chicken Carcass Rinse

Introduction: Although there have been many commercialized Campylobacter-selective agars such as Campy-cefex agar, modified cefoperazone charcoal deoxycholate agar, and Karmali agar, it has been reported that these cefoperazone-based media are unsuitable for isolation of Campylobacter from poultry samples because the cefoperazone cannot suppress competing flora such as extended-spectrum-β-lactamase (ESBL)-producing E. coli sufficiently

Purpose: We compared the performance of tazobactam-supplemented Karmali agar (T-Karmali agar) with normal Karmali agar during the isolation of Campylobacter from whole chicken carcass rinse.

Methods: All samples were rinsed with 400 ml of buffered peptone water. The 25 ml of subsamples were enriched with 2 x blood-free Bolton enrichment broth prior to incubation at 42°C for 48 h. Pre-enriched broths were streaked onto Karmali and T-Karmali agar. The presumptive colonies were finally confirmed by colony PCR.

Results: The isolation rate of T-Karmali agar was slightly higher (P > 0.05) than that of normal Karmali agar (T-Karmali, 16 of 120; Karmali, 10 of 120). However, the selectivity (T-Karmali, 25 out of 120; Karmali, 99 out of 120) and growth index (T-Karmali, 1.36; Karmali, 2.83) of the T-Karmali agar was significantly better (P < 0.05) than that of normal Karmali agar.

Significance: The T-Karmali agar showed more selectivity than normal Karmali agar for isolation of Campylobacter.