浙江省猪链球菌人源感染株的耐药检测分析

Antimicrobial resistance analysis of Streptococcus suis strains isolated from human in Zhejiang Province

目的了解浙江省猪链球菌人源感染株在体外对抗菌药物的耐药性和耐药基因携带状况。方法收集2005年至2021年浙江省31株猪链球菌人源感染散发株,通过微量稀释法测定15种抗菌药物对所有菌株的最低抑菌浓度,利用聚合酶链反应检测四环素类、大环内酯类和氨基糖苷类等70种耐药基因。结果31株菌株对头孢吡肟、头孢噻肟、头孢曲松、氯霉素、达托霉素、厄他培南、左氧氟沙星、利奈唑胺、美罗培南、青霉素、万古霉素11种抗菌药物均敏感,敏感率达到96.8%及以上,对四环素、克林霉素、阿奇霉素、红霉素均耐药,特别是对四环素的耐药率达93.5%(29/31),多重耐药株共14株(45.2%)。70种耐药基因检测中,共检出14种(20.0%)耐药基因。耐药基因检出率高的主要为耐四环素类基因,依次是tet(O)[58.1%(18/31)]、tet(M)[48.4%(15/31)]、tet(40)[35.5%(11/31)];其次是耐大环内酯类ermB基因[41.9%(13/31)];14株(45.2%)同时检出3种以上耐药基因,其中8株(25.8%)检出10种耐药基因。耐药基因结果与序列分型结合分析显示,tet(M)+ST7占35.5%(11/31),tet(O)+tet(40)+ermB+mef(A)+mef(A/E)+msrD+Ant(6)-Ⅰb+aph(3′)-Ⅲa+aadB+sat4+ST7占25.8%(8/31)。结论浙江省猪链球菌人源感染散发株的抗菌药物耐药情况及耐药基因携带状况均呈地方性特征,主要流行2种特征型的耐药基因遗传克隆。

Objective To understand the in vitro antimicrobial resistance and resistance phenotypes profile of Streptococcus suis strains isolated from human in Zhejiang Province.Methods The strains of sporadic Streptococcus suis infections were isolated during 2005 to 2021 in Zhejiang Province,and were subjected to antimicrobial resistance analysis using agar dilution method.Polymerase chain reaction(PCR)technology was also used to detect 70 resistance genes including tetracyclines,macrolides and aminoglycosides.Results The results of antimicrobial resistance analysis showed that these strains were sensitive to eleven kinds of antimicrobial agents with a sensitivity rate≥96.8%,including cefepime,cefotaxime,ceftriaxone,chloramphenicol,daptomycin,ertapenem,levofloxacin,linezolid,meropenem,penicillin and vancomycin.These strains were mainly resistant to tetracycline,clindamycin,azithromycin and erythromycin,especially resistant to tetracycline with a rate of 93.5%(29/31).Fourteen strains(45.2%)exhibited multidrug resistant patterns.The PCR analysis of 70 drug resistance genes showed that 14(20.0%)different resistance genes were detected.The highest detection rate of resistant genes came from tetracycline,including tet(O)gene(58.1%,18/31),tet(M)gene(48.4%,15/31),tet(40)gene(35.5%,11/31),followed by ermB gene(41.9%,13/31)in the class of macrolide.Fourteen strains(45.2%)with more than three drug resistance genes were detected,of which eight strains(25.8%)detected 10 drug resistance genes.The analysis of antibiotic resistance and resistance phenotypes profile showed that tet(M)+ST7 accounted for 35.5%(11/31),tet(O)+tet(40)+ermB+mef(A)+mef(A/E)+msrD+Ant(6)-Ⅰb+aph(3′)-Ⅲa+aadB+sat4+ST7 accounted for 25.8%(8/31).Conclusions The antimicrobial resistance and resistance phenotypes profile of sporadic Streptococcus suis strains isolated from human in Zhejiang Province are endemic,with mainly two types of characteristic genetic cloning of drug resistance genes.