Data_Sheet_1_Antimicrobial Resistance Profiles, Virulence Genes, and Genetic Diversity of Thermophilic Campylobacter Species Isolated From a Layer Poultry Farm in Korea.pdf

Thermophilic Campylobacter species are among the major etiologies of bacterial enteritis globally. This study aimed at assessing the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in South Korea. One hundred fifty-three chicken feces were collected from two layer poultry farms in Gangneung, South Korea. The Campylobacter species were isolated by cultural techniques, while PCR and sequencing were used for species confirmation. Antimicrobial susceptibility testing for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)] was carried out by broth microdilution. Three AMR and nine virulence genes were screened by PCR. Genotyping was performed by flaA-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%), with Campylobacter jejuni and Campylobacter coli being 49 (89.1%) and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL (100%), and TET (C. jejuni, 93.9%; C. coli: 83.3%). No resistance was observed for SIT. The missense mutation (C257T) in gyrA gene was confirmed by sequencing, while the tet(O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant (MDR) strains was 8.2%, and they all belonged to C. jejuni. All Campylobacter isolates possessed five virulence genes (cdtB, cstII, flaA, cadF, and dnaJ), but none possessed ggt, while the rates for other genes (csrA, ciaB, and pldA) ranged between 33.3 and 95.9%. The flaA-RFLP yielded 26 flaA types (C. jejuni: 21 and C. coli: five), while the MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli, with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The findings of this study highlight the increased resistance to quinolones and TET, the virulence potential, and the diverse genotypes among Campylobacter strains isolated from the layer poultry farm.

嗜热弯曲菌属（Thermophilic Campylobacter species）是全球细菌性肠炎的主要致病菌之一。本研究旨在评估从韩国某蛋鸡场分离得到的嗜热弯曲菌属菌株的抗菌药物耐药性（antimicrobial resistance, AMR）谱、毒力基因及遗传多样性。研究人员从韩国江陵的两家蛋鸡场采集了153份鸡粪便样本。采用培养技术分离弯曲菌属，通过聚合酶链式反应（polymerase chain reaction, PCR）和测序进行菌种确认。针对六种抗菌药物——环丙沙星（ciprofloxacin, CIP）、萘啶酸（nalidixic acid, NAL）、司氟沙星（sitafloxacin, SIT）、红霉素（erythromycin, ERY）、四环素（tetracycline, TET）和庆大霉素（gentamicin, GEN）——采用微量肉汤稀释法开展药敏试验。通过PCR筛查了3种耐药基因与9种毒力基因。基因分型采用flaA限制性片段长度多态性（restriction fragment length polymorphism, RFLP）和多位点序列分型（multilocus sequence typing, MLST）。在153份样本中，55份（35.9%）检出弯曲菌属，其中空肠弯曲菌（Campylobacter jejuni）49株（89.1%）、结肠弯曲菌（Campylobacter coli）6株（10.9%）。研究观察到菌株对环丙沙星（100%）、萘啶酸（100%）及四环素（空肠弯曲菌93.9%；结肠弯曲菌83.3%）呈现高水平耐药，未检出对司氟沙星的耐药性。通过测序证实了gyrA基因存在C257T错义突变，而tet(O)基因与GenBank中的已知序列一致。多重耐药（multidrug-resistant, MDR）菌株的检出率为8.2%，且均为空肠弯曲菌。所有弯曲菌分离株均携带cdtB、cstII、flaA、cadF与dnaJ这5种毒力基因，未检出ggt基因；其余基因（csrA、ciaB与pldA）的检出率介于33.3%至95.9%之间。flaA-RFLP分型共得到26个flaA型别（空肠弯曲菌21个，结肠弯曲菌5个）；MLST分型显示空肠弯曲菌存在10个序列型（sequence types, STs），结肠弯曲菌存在3个STs，其中以CC-607（ST3611）与CC-460（ST-460）为优势型别。在空肠弯曲菌的10个STs中，有3个为新分配的型别。本研究结果凸显了该蛋鸡场分离的弯曲菌菌株对喹诺酮类与四环素的耐药性上升、毒力潜力及多样的基因型。