Gahamanyi Noel, Song Dae-Geun, Yoon Kye-Yoon, Mboera Leonard E G, Matee Mecky I, Mutangana Dieudonné, Amachawadi Raghavendra G, Komba Erick V G, Pan Cheol-Ho
Natural Product Informatics Research Center, KIST Gangneung Institute of Natural Products, Gangneung, South Korea.
SACIDS Foundation for One Health, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania.
Front Microbiol. 2021 Mar 29;12:622275. doi: 10.3389/fmicb.2021.622275. eCollection 2021.
Thermophilic 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 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 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 A-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Of the 153 samples, spp. were detected in 55 (35.9%), with and being 49 (89.1%) and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL (100%), and TET (, 93.9%; : 83.3%). No resistance was observed for SIT. The missense mutation (C257T) in A gene was confirmed by sequencing, while the (O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant (MDR) strains was 8.2%, and they all belonged to . All isolates possessed five virulence genes (B, II, A, F, and J), but none possessed , while the rates for other genes (A, B, and A) ranged between 33.3 and 95.9%. The A-RFLP yielded 26 A types (: 21 and : five), while the MLST showed 10 sequence types (STs) for and three STs for , with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of , 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 strains isolated from the layer poultry farm.
嗜热菌是全球细菌性肠炎的主要病因之一。本研究旨在评估从韩国一个蛋鸡养殖场分离出的嗜热菌的抗菌药物耐药性（AMR）谱、毒力基因和遗传多样性。从韩国江陵的两个蛋鸡养殖场收集了153份鸡粪便。通过培养技术分离菌种，同时使用PCR和测序进行菌种鉴定。采用肉汤微量稀释法对六种抗菌药物[环丙沙星（CIP）、萘啶酸（NAL）、司帕沙星（SIT）、红霉素（ERY）、四环素（TET）和庆大霉素（GEN）]进行药敏试验。通过PCR筛选三种AMR基因和九种毒力基因。通过A-限制性片段长度多态性（RFLP）和多位点序列分型（MLST）进行基因分型。在153份样本中，55份（35.9%）检测到嗜热栖热放线菌，其中嗜热栖热放线菌和嗜热栖热放线菌分别为49份（89.1%）和6份（10.9%）。观察到对CIP（100%）、NAL（100%）和TET（嗜热栖热放线菌为93.9%；嗜热栖热放线菌为83.3%）的高水平耐药。未观察到对SIT的耐药。通过测序确认了A基因中的错义突变（C257T），而（O）基因与GenBank中的已知序列相似。多重耐药（MDR）菌株的比例为8.2%，且均属于嗜热栖热放线菌。所有嗜热栖热放线菌分离株均具有五个毒力基因（B、II、A、F和J），但均不具有，而其他基因（A、B和A）的比例在33.3%至95.9%之间。A-RFLP产生了26种A类型（嗜热栖热放线菌为21种，嗜热栖热放线菌为5种），而MLST显示嗜热栖热放线菌有10种序列类型（STs），嗜热栖热放线菌有3种STs，其中CC-607（STs 3611）和CC-460（ST-460）占主导。在嗜热栖热放线菌的10种STs中，有三种是新指定的。本研究结果突出了从蛋鸡养殖场分离出的嗜热菌对喹诺酮类和TET耐药性增加、毒力潜力以及多样的基因型。
