上海地区支气管扩张症患者铜绿假单胞菌耐药机制和分子流行病学特征

Resistance mechanisms and molecular epidemiology of Pseudomonas aeruginosa from patients with bronchiectasis in Shanghai

目的了解上海地区支气管扩张症患者铜绿假单胞菌(PA)耐药性和分子流行病学特征。方法收集分离自上海地区6家医院支气管扩张症患者痰样本的PA 73株。采用微量肉汤稀释法检测菌株对抗菌药物的敏感性。采用高通量测序(NGS)检测分离菌株的耐药基因,并进行多位点序列分型(MLST)。结果73株PA中,黏液型PA 43株(58.9%)。对左氧氟沙星、环丙沙星、亚胺培南的耐药率分别为41.1%、34.2%、12.3%,对其他类抗菌药物的耐药率均<6%。对氟喹诺酮类抗菌药物耐药的PA最主要的突变位点为GyrA的83位和87位、GyrB的466位、ParC的646位和262位、ParE的533位;对亚胺培南耐药的PA膜孔蛋白OprD全部存在突变或缺失。检测到多种获得性耐药基因,包括β-内酰胺类(blaIMP-45、blaPAO、blaOXA-1、blaOXA-50等)、氨基糖苷类[aph(3’)-Iib、aac(6’)-Ib3、aac(6’)-Ib-cr、aadA2b]、磷霉素类(fosA)、氯霉素类(catB7、catB3)、磺胺类(sul1、qacE)和喹诺酮类(crpP)。MLST共检测出53个ST型别,最常见的是ST277(5.5%,4/73)。结论上海地区支气管扩张症患者携带的PA大部分为黏液型,总体耐药率较低,但对氟喹诺酮类药物耐药性较高,不存在菌株的克隆传播。

Objective To investigate the drug resistance and molecular epidemiological characteristics of Pseudomonas aeruginosa(PA)isolated from patients with bronchiectasis in Shanghai.Methods Totally,73 isolates of PA from sputum samples of patients with bronchiectasis in 6 hospitals in Shanghai were collected.The durg susceptibility was analyzed by microbroth dilution method.The resistance mechanisms were assessed by next generation sequencing(NGS),and the molecular epidemiological characteristics were determined by multilocus sequence typing(MLST).Results A total of 73 isolates of PA were collected,which included 43 mucous PA(58.9%).The highest resistance rates were observed for levofloxacin(41.1%),ciprofloxacin(34.2%)and imipenem(12.3%),and the resistance rates to other antibiotics were all<6%.The most frequent mutation sites of PA which were resistant to fluoroquinolones were concentrated on the 83rd and 87th sites of GyrA,the 466th site of GyrB,the 646th and the 262nd sites of ParC and the 533rd site of ParE.All the outer membrane porin D(OprD)of PA which were resistant to imipenem were mutated or missed.Multiple acquired resistance genes were determined,which included beta-lactamases(blaIMP-45,blaPAO,blaOXA-1,blaOXA-50 and so on),aminoglycosides[aph(3')-Iib,aac(6')-Ib3,aac(6')-Ib-cr,aadA2b],fosfomycin(fosA),amphetamines(catB7,catB3),sulfonamides(sul1,qacE),quinolones(crpP).A total of 53 sequence types(ST)were determined.The most common ST was ST277(5.5%,4/73).Conclusions Most of PA isolated from sputum samples of bronchiectasis patients in Shanghai are mucous types.These isolates are highly susceptible to common used antibiotics except fluoroquinolones.Multiclonality discloses no evidence on spread of specific types of PA in Shanghai.