Antimicrobial Resistance and Genomic Characteristics of Campylobacter spp. from Australian Meat Chickens

The increasing resistance of bacteria to antimicrobials is a major threat to public health. This study focuses on the antimicrobial resistance (AMR) profiles and genetic relationships of Campylobacter jejuni and Campylobacter coli. Isolates (n = 186) were obtained at slaughter from 200 pooled cecal samples taken from 1,000 meat chickens. Majority of C. jejuni (68.7%) and C. coli (88.9%) isolates were susceptible to all antimicrobials and no multi-drug resistance was found. Resistance to ciprofloxacin (fluoroquinolone) was detected in 24.4% of the C. jejuni and 3.2% of the C. coli isolates. Whole genome sequencing revealed a diverse range of sequence types (STs). These included 32 previously reported STs for C. jejuni and 13 for C. coli, as well as four and seven previously undescribed STs for each species, respectively. The STs containing fluoroquinolone-resistant isolates were ST2083, ST10130, ST2895, ST7323, ST2398, and ST1078 for C. jejuni, and ST860 and ST894 for C. coli. Although fluoroquinolones are not used in animal production in Australia, resistance amongst C. jejuni isolates was high (24.4%). This finding emphasizes the need for enhanced surveillance and sampling along the food chain to understand the source of the isolates and to mitigate risks of AMR to protect public health.

细菌对抗菌剂的耐药性日益增强，已成为公共卫生面临的重大威胁。本研究聚焦于空肠弯曲菌（Campylobacter jejuni）和结肠弯曲菌（Campylobacter coli）的抗菌药物耐药性（antimicrobial resistance, AMR）谱及其遗传关系。本研究共获得186株分离株，均采自屠宰场，源自1000只肉用肉鸡的200份混合盲肠样本。绝大多数空肠弯曲菌（68.7%）与结肠弯曲菌（88.9%）分离株对所有受试抗菌剂均敏感，未发现多重耐药菌株。环丙沙星（氟喹诺酮类）的耐药性在24.4%的空肠弯曲菌分离株及3.2%的结肠弯曲菌分离株中被检出。全基因组测序结果显示，两类弯曲菌存在多种序列型（sequence types, STs）：其中空肠弯曲菌包含32种已报道的STs，结肠弯曲菌包含13种已报道的STs，此外两个菌种分别存在4种和7种此前未被报道的STs。携带氟喹诺酮类耐药菌株的序列型包括：空肠弯曲菌的ST2083、ST10130、ST2895、ST7323、ST2398与ST1078，以及结肠弯曲菌的ST860和ST894。尽管澳大利亚的动物养殖中未使用氟喹诺酮类药物，但空肠弯曲菌分离株的耐药率仍高达24.4%。这一发现凸显了加强食物链全程监测与采样的必要性，以明确分离株的来源并降低抗菌药物耐药性相关风险，进而保护公共卫生。