Evaluation of Tazobactam-Supplemented, Modified Charcoal-Cefoperazone-Deoxycholate Agar for Qualitative Detection of Campylobacter from Chicken Carcass Rinse

Development of a selective media for detecting Campylobacter spp. in chicken carcasses using avibactam supplemented mCCDA

Campylobacter spp. are major causes of gastrointestinal infections worldwide, and are commonly identified using modified-charcoal-cefoperazone-deoxycholate agar (mCCDA). However, the efficacy of this screening technique is often hindered by overgrowth of competing flora, such as extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Thus, in the present study we supplemented mCCDA with a recently developed ESBL inhibitor, avibactam (A-mCCDA). We inoculated mCCDA and A-mCCDA plates with 25 strains each of Campylobacter spp. and ESBL-producing E. coli, and thereby determined that the optimum avibactam concentration required to inhibit ESBL-producing E. coli was 0.0625 mg/L. At this concentration, a significantly higher proportion of Campylobacter spp. was isolated using A-mCCDA compared to that using mCCDA (P < 0.05). Thus, the results of the present study support the use of A-mCCDA to improve current Campylobacter screening methods.

Improvement of Bolton broth by supplementation with tazobactam for the isolation of Campylobacter from chicken rinses

Overgrowth of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) on Campylobacter media prevents the latter's selective isolation, thereby making the improvement of Campylobacter-selective media necessary. We evaluated tazobactam (an ESBL inhibitor) to supplement Bolton enrichment broth (Tz-Bolton broth) for the selective isolation of Campylobacter in chicken carcass rinses. First, using 20 strains of ESBL-producing E. coli and 13 Campylobacter strains, we found 4 μg/mL of tazobactam to be optimal for inhibiting the ESBL-producing E. coli while allowing the growth of all tested Campylobacter strains. Next, 80 whole chicken carcasses were rinsed with buffered peptone water (BPW), and 25 mL of BPW rinse was mixed with 2 × blood-free Bolton broth (25 mL) with or without tazobactam followed by incubation at 42°C for 48 h under microaerobic conditions. A loopful of the incubated broth was inoculated on modified charcoal-cefoperazone-deoxycholate agar (mCCDA) and microaerobically incubated at 42°C for 48 h. The tazobactam supplemented Bolton broth showed a higher Campylobacter isolation rate (38.8%, p < 0.05) than normal Bolton broth (15%). Moreover, the number of mCCDA plates with non-Campylobacter was much lower (p < 0.05) after enrichment in Tz-Bolton broth (0%) than in the normal Bolton broth (80%), suggesting that selectivity of the modified broth was superior to normal Bolton broth.