福建省36株人源猪链球菌分离株病原学特征分析

Analysis of the pathogenic characteristics of 36 isolates of Streptococcus suis from human-origin in Fujian Province

目的了解福建省2005-2023年猪链球菌菌株病原学和基因组特征,分析18年间分离株进化特征,为人感染猪链球菌病防控提供参考依据。方法对36株福建地区分离自人的猪链球菌菌株进行全基因组测序、药物敏感性测试,检测血清型分布、耐药表型和基因分型,分析菌株之间的遗传多态性。结果福建省36株人感染猪链球菌分离株以血清2型(97.2%)为主,其次是5型(2.8%);全基因组测序结果显示36株分离株有5种不同的序列类型,以ST1型(58.3%)和ST7型(30.6%)最为常见;药物敏感性测试显示对大环内酯类、四环素和氨基糖苷类药物具有高水平的耐药性。存在多重耐药情况,7重耐药菌株(2.8%),5重耐药菌株(5.6%),4重耐药菌株(47.2%),3重耐药菌株(27.8%);对四环素(100%)、红霉素(83.3%)、克林霉素(83.3%)及复方新诺明(55.6%)耐药率高。分离株携带19种抗生素耐药基因,对8类抗生素产生耐药性,耐药基因分型与观察到的表型直接相关。结论应继续加强对福建地区人感染猪链球菌疫情的监测,针对不同地区的不同优势毒力基因型进行预防;限制抗生素的使用,同时加强对耐药相关可移动元件的监测,以减少潜在的抗微生物药物耐药性。

This study was aimed at understanding the etiological and genomic characteristics of Streptococcus suis(S.suis)strains in Fujian province from 2005 to 2023,and analyzing the evolutionary traits of the isolates over the past 18 years,to provide guidance for preventing and controlling human infections caused by S.suis.A total of 36 strains of Streptococcus suis isolated from individuals in Fujian province were subjected to whole genome sequencing and drug susceptibility testing.The serotype distribution,drug resistance phenotype,and gene typing were determined,and genetic polymorphisms among strains were analyzed.Among the 36 S.suis isolates in Fujian province,serotype 2 accounted for the majority(97.2%)and was followed by serotype 5(2.8%).Whole genome sequencing indicated that 36 isolates had 5 different sequence types,among which ST1(58.3%)and ST7(30.6%)were the most common.Drug susceptibility testing revealed high levels of resistance to macrolides,tetracyclines,and aminoglycosides.The prevalence of multi-drug resistance was 2.8%(seven strains),5.6%(five strains),47.2%(four strains),and 27.8%(three strains).High resistance was observed to tetracycline(100%),erythromycin(83.3%),clindamycin(83.3%),and compound sulfamethoxazole(55.6%).The isolates carried 19 antibiotic resistance genes and were resistant to eight classes of antibiotics.Resistance genotyping results directly correlated with the observed phenotype.Surveillance of Streptococcus suis(S.suis)in Fujian province must be further enhanced,and prevention measures should be conducted according to the dominant virulence genotypes in different regions.The use of antibiotics should be limited,and monitoring of resistance-associated mobile elements should be enhanced to decrease potential antimicrobial resistance.