Antimicrobial Resistance Determinants Circulating among Thermophilic <i>Campylobacter</i> Isolates Recovered from Broilers in Ireland Over a One-Year Period

• Main Authors: Caoimhe T. Lynch (Author), Helen Lynch (Author), Sarah Burke (Author), Kayleigh Hawkins (Author), Colin Buttimer (Author), Conor Mc Carthy (Author), John Egan (Author), Paul Whyte (Author), Declan Bolton (Author), Aidan Coffey (Author), Brigid Lucey (Author)
• Format: Book
• Published: MDPI AG, 2020-06-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Campylobacteriosis is the leading cause of human bacterial gastroenteritis, very often associated with poultry consumption. Thermophilic <i>Campylobacter</i> (<i>Campylobacter jejuni</i> and <i>Campylobacter coli</i>) isolates (<i>n</i> = 158) recovered from broiler neck skin and caecal contents in Ireland over a one-year period, resistant to at least one of three clinically relevant antimicrobial classes, were screened for resistance determinants. All ciprofloxacin-resistant isolates (<i>n</i> = 99) harboured the C257T nucleotide mutation (conferring the Thr-86-Ile substitution) in conjunction with other synonymous and nonsynonymous mutations, which may have epidemiological value. The A2075G nucleotide mutation and amino acid substitutions in L4 and L22 were detected in all erythromycin-resistant isolates (<i>n</i> = 5). The <i>tetO</i> gene was detected in 100% (<i>n</i> = 119) of tetracycline-resistant isolates and three of which were found to harbour the mosaic tetracycline resistance gene <i>tetO/32/O</i>. Two streptomycin-resistant <i>C. jejuni</i> isolates (isolated from the same flock) harboured <i>ant(6)-Ib</i>, located in a multidrug resistance genomic island, containing aminoglycoside, streptothricin (<i>satA</i>) and tetracycline resistance genes (truncated <i>tetO</i> and mosaic <i>tetO/32/O</i>). The <i>ant(6)-Ie</i> gene was identified in two streptomycin-resistant <i>C. coli</i> isolates. This study highlights the widespread acquisition of antimicrobial resistance determinants among chicken-associated <i>Campylobacter</i> isolates, through horizontal gene transfer or clonal expansion of resistant lineages. The stability of such resistance determinants is compounded by the fluidity of mobile genetic element.

Item Description

10.3390/antibiotics9060308
2079-6382