July 18, 2024

Study finds higher campylobacter prevalence in North Carolina, US, backyard chickens compared to commercial farms

A recent prevalence study published in JAC - Antimicrobial Resistance on the common foodborne bacterium Campylobacter in chickens in North Carolina, US, revealed it is almost twice as common in backyard flocks compared to commercial farms, with isolates often resistant to antibiotics.

North Carolina state investigators collected samples from 10 backyard and 10 commercial broiler farms in North Carolina, monitoring flocks throughout their production cycles. Faecal and environmental samples were gathered at days 10, 31, and 52 post-hatch for backyard flocks, and at days 10, 24, and 38 for commercial farms. Environmental samples were taken from soil, litter/compost, and feeders and waterers.

Results showed that 21.9% of samples from backyard flocks tested positive for Campylobacter, compared to 12.2% from commercial farms. Most isolates were identified as C. jejuni (70.8%), with the remainder as C. coli (29.2%). In backyard farms, 70.2% of positive samples were from faecal samples, 6.4% from soil, 3.5% from litter/compost, and 19.9% from swabs of feeders and waterers. On commercial farms, the rates were 84.2%, 0%, 12.6%, and 3.2%, respectively.

Antimicrobial susceptibility testing indicated phenotypic resistance to ciprofloxacin (40.2%) and tetracycline (46.6%), both important treatment drugs for Campylobacter. The study found a higher proportion of resistance in C. jejuni isolates and on commercial farms.

The authors concluded, "Despite higher prevalence in backyard farms, we found a higher proportion of resistant isolates in commercial farms, with unprecedented higher levels in C. jejuni versus C. coli."

The authors emphasised the significance of these findings, given that chicken is the most consumed meat worldwide and backyard poultry production is increasing in the US.

-      US Centre for Infectious Disease Research and Policy