儿童来源肠道沙门菌肠道亚种非A~F群血清型分离株的耐药性及分子流行病学和毒力基因分布

Resistance, molecular epidemiology and virulence gene of non-A-F group serotype isolates of Salmonella enterica enteric subspecies isolated from children

目的分析肠道沙门菌肠道亚种非A~F群血清型分离株的耐药性、分子流行病学和毒力基因分布情况,以明确其流行特点,为临床诊疗提供流行病学依据。方法针对浙江大学医学院附属儿童医院2017—2020年收集的11株肠道沙门菌肠道亚种非A~F群血清型分离株,进行血清分型及抗菌药物敏感性试验,并进行全基因组测序,进而对测序结果进行血清型、多位点序列分型和毒力基因分析。结果本院肠道沙门菌肠道亚种非A~F群血清型分离株检出率较低,占比1.13%。11株菌株中,包含长湾尼血清型3株,非丁伏斯血清型2株,汪兹沃思、波摩那、凯杜古、厄班那、浦那、库马西血清型各1株。11株非A~F群肠道沙门菌肠道亚种分离株中除2株多重耐药株外,其余菌株对绝大多数抗菌药物均敏感,且最低抑菌浓度(MIC)均处于较低水平。11株菌共检测出9种ST型,3株长湾尼血清型菌株均为ST3918,其他分离株分别为不同的ST型。通过核心基因组构建进化树显示3株长湾尼血清型菌株亲缘关系紧密。11株菌株共检测出毒力基因103种,包含分泌系统相关基因78种,黏附相关基因21种,镁吸收相关基因2种,抗菌肽耐药性相关基因1种,伤寒毒素相关基因1种。结论本院肠道沙门菌肠道亚种非A~F群血清型分离株的检出率较低,对常见抗菌药物敏感性较高,ST型及亲缘关系呈多样性分布。临床实验室应关注肠道沙门菌肠道亚种非A~F群血清型分离株的检出,并持续关注其耐药性和毒力基因变化。

Objective To analyze the anti-drug resistance,molecular epidemiology and virulence gene distribution of non-A-F group serotype isolates of Salmonella enterica enteric subspecis,so as to provide epidemiological basis for clinical diagnosis and treatment.Methods Serotyping,antimicrobial susceptibility test and whole genome sequencing were performed on 11 isolates of non-A-F group serotype isolates of Salmonella enterica enteric subspecies that were isolated from The Children′s Hospital,Zhejiang University School of Medicine between 2017 and 2020.The serotype,multilocus sequence typing and virulence gene of the whole genome sequencing results were analyzed.Results In our hospital,the detection rate of non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low(1.13%).Among the 11 strains,there were 3 strains belong to Jangwani serotype,2 strains of Hvittingfoss serotype,and Wandsworth,Pomona,Kedougou,Urbana,Poona and Kumasi serotypes have 1 strain each.Except for the two multi-drug resistant strains,the other strains were sensitive to most antibiotics,and the MICs were at low levels.A total of 9 ST types were detected in the 11 strains,the 3 Jangwani serotype strains were ST3918,and the other isolates were of different ST types.The phylogenetic tree shown that the three strains of Jangwani serotype were closely related.A total of 103 virulence genes were detected in the 11 strains,including 78 genes related to secretion system,21 genes related to adherence,2 genes related to magnesium uptake,1 gene related to resistance to antimicrobial peptides and 1 gene related to typhoid toxin.Conclusions The detection rate of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low,and the sensitivity of the isolates to common antibiotics was high.The ST types and genetic relationship showed diversity.Clinical laboratory should pay attention to the detection of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies,and the changes in drug resistance and virulence genes of the isolates should be closely monitored.