广东地区类鼻疽伯克霍尔德菌耐药特征及分子流行病学分析

Antibiotic resistance of Burkholderia pseudomallei isolates from Guangdong province:a molecular epidemiology study

目的了解广东地区类鼻疽伯克霍尔德菌的耐药状况及分子流行病学特征,为该地区类鼻疽病的监测防控、临床诊疗等方面提供理论基础。方法对2018—2019年收集的8株类鼻疽伯克霍尔德菌采用微量肉汤稀释法进行抗生素药物敏感性试验;利用全基因组测序技术获得菌株耐药基因携带情况,并进行分子分型研究及系统发育进化树的构建。结果8株类鼻疽伯克霍尔德菌对四环素、头孢他啶、亚胺培南、阿莫西林-克拉维酸、多西环素和复方新诺明这6种抗生素均表现敏感。除菌株19BP04外均检测到耐药基因bla_(A-59),有3株菌检测到bla_(A-57)耐药基因。MLST分型结果为8种不同ST型(ST271、ST562、ST10、ST46、ST1325、ST830、ST1774、ST1775),其中ST1774和ST1775为全球新发的首次报道序列型别。全基因组单核苷酸多态性(wgSNPs)系统发育进化分析结果显示,8株类鼻疽伯克霍尔德菌分属于不同聚类分支,与多个不同地理来源分离株具有邻近的亲缘关系。结论广东地区类鼻疽伯克霍尔德菌对常用的临床治疗抗菌药物尚未产生耐药,基因组具有较高的遗传多样性,并且变异进化迅速,基因组发生重组等可塑性强。

Objective To study drug resistance and molecular epidemiological characteristics of Burkholderia pseudomallei(Bp)strains isolated in Guangdong province and to provide evidences for surveillance,diagnosis and treatment,and prevention of melioidosis.Methods Broth microdilution method was used to determine the minimum inhibitory concentrations(MICs)of antimicrobial susceptibility for 8 Bp strains clinically isolated in Guangdong province from 2018 through 2019.Whole genome sequencing was used to identify drug-resistant genes and to conduct molecular typing and phylogenetic tree construction for the Bp strains.Results All the Bp stains were sensitive to tetracycline,ceftazidime,imipenem,amoxicillin-clavulanic acid,doxycycline and sulfamethoxazole.Drug-resistance gene bla_(A-59)was detected in 7 of the 8 strains and the drug-resistance gene bla_(A-57)was detected in 3 strains.Multilocus sequence typing(MLST)analysis showed that the 8 strains belonged to different sequence types(ST271,ST562,ST10,ST46,ST1325,ST830,ST1774,and ST1775),and 2 of them were novel types.Whole-genome single nucleotide polymorphism(wgS-NPs)phylogenetic evolution analysis demonstrated that the 8 Bp stains belonged to different clusters and closely related to several strains isolated in different geographical regions.Conclusion Burkholderia pseudostellariae stains isolated in Guangdong province were not resistant to antibacterials commonly used in clinic treatment and the genomes of the strains have high genetic diversities with rapid mutation and high probability of genome recombination.