Abstract：
Riemerella anatipestifer is one of the important bacterial pathogens that threaten the waterfowl farming industry. In this study, 157 suspected R. anatipestifer strains were isolated from diseased ducks and geese from seven regions of China during 2019-2020, and identified using multiple polymerase chain reaction (PCR). Antimicrobial susceptibility tests and whole-genome sequence (WGS) analysis were then performed for comparative analysis of antimicrobial resistance phenotypes and genotypes. The results showed that these strains were susceptible to florfenicol, ceftriaxone, spectinomycin, sulfafurazole and cefepime, but resistant to kanamycin, amikacin, gentamicin, and streptomycin, exhibiting multiple antimicrobial resistance phenotypes. WGS analysis revealed a wide distribution of genotypes among the 157 strains with no apparent regional pattern. Through next-generation sequencing analysis of antimicrobial resistance genes, a total of 88 resistance genes were identified. Of them, 19 tetracycline resistance genes were most commonly found, followed by 15 efflux pump resistance genes, 11 glycopeptide resistance genes and seven macrolide resistance genes. The 157 R. anatipestifer strains contained 42-55 resistance genes each, with the strains carrying 47 different resistance genes being the most abundant. By comparing the antimicrobial resistance phenotype and genotype, it was observed that a high correlation between them for most antimicrobial resistance properties was detected, except for a difference in aminoglycoside resistance phenotype and genotype. In conclusion, 157 R. anatipestifer strains exhibited severe multiple antimicrobial resistance phenotypes and genotypes, emphasizing the need for improved antimicrobial usage guidelines. The wide distribution and diverse types of resistance genes among these strains provide a foundation for studying novel mechanisms of antimicrobial resistance.
摘要：
鼠疫Riemerella是威胁水禽养殖业的重要细菌病原体之一。在这项研究中,在2019-2020年期间，从来自中国七个地区的患病鸭和鹅中分离出157个可疑的R.anatipestifer菌株，并使用多重聚合酶链反应（PCR）进行鉴定。然后进行抗菌素敏感性测试和全基因组序列（WGS）分析，以比较分析抗菌素耐药性表型和基因型。结果表明，这些菌株对氟苯尼考敏感，头孢曲松,壮观霉素,磺脲咔唑和头孢吡肟，但对卡那霉素有抗性,阿米卡星，庆大霉素,和链霉素,表现出多种抗生素抗性表型。WGS分析显示，在157个菌株中，基因型分布广泛，没有明显的区域模式。通过对抗菌素耐药基因的下一代测序分析，共鉴定出88个抗性基因。其中,最常见的有19个四环素抗性基因，其次是15个外排泵抗性基因，11个糖肽抗性基因和7个大环内酯抗性基因。157株根除鼠疫菌菌株每个含有42-55个抗性基因，其中携带47种不同抗性基因的菌株最丰富。通过比较耐药性表型和基因型,据观察，它们与大多数抗菌素耐药性特性之间的高度相关性被检测到，除了氨基糖苷类耐药表型和基因型不同。总之,157株厌氧菌菌株表现出严重的多重抗菌素耐药性表型和基因型，强调需要改进抗菌药物使用指南。这些菌株中耐药基因分布广泛、类型多样,为研究抗菌素耐药的新机制奠定了基础。
