华东地区猪丹毒杆菌分离株的生物学特征及其耐药性分析

旨在了解华东地区猪场猪丹毒杆菌的生物学特征以及对临床常用抗菌药的耐药情况。通过对2017-2018 年华东地区猪场临床疑似猪丹毒感染的266份病料进行细菌分离、分析其生化特性、血清型、小鼠致病性等生物学特征,并进行16S rDNA 序列遗传进化分析和药物敏感性测定。经分离和鉴定共获得20株猪丹毒杆菌,血清型均为1a 型,能100%致死小鼠,具有猪丹毒杆菌的生化特性,16S rDNA 序列与国内外参考菌株、临床流行株的同源性达99%以上;现有商品化猪丹毒弱毒疫苗免疫小鼠后,分别以致死剂量的的5株猪丹毒杆菌分离株腹腔攻毒小鼠,免疫保护率均为100%。所有分离株对青霉素(PEN)、氨苄西林(AMP)、红霉素(ERY)、替米考星(TIL)、头孢噻呋(CEF)、头孢曲松(CRO)和氟苯尼考(FFC)敏感。然而,对林可酰胺类、喹诺酮类、氨基糖苷类、四环素类、磺胺类和多肽类抗生素有不同程度的多重耐药现象。本研究明确了华东地区猪丹毒杆菌的生物学特性和耐药情况,现有商品化猪丹毒弱毒疫苗对分离的强毒株可提供完全的免疫保护,为当地猪丹毒的有效防控提供了数据。

Biological Characteristics and Antibiotic Resistance of Erysipelothrix rhusiopathiae Isolated from East China

The aim of this study is to investigate the biological characteristics of Erysipelothrix rhusiopathiae originated from pig farms in East China and its resistance to common clinical antibiotics.A total of 266 samples of pigs suspected to be infected by E.rhusiopathiae in pig farms of East China during 2017-2018 were collected and isolated,their biochemical characteristics,serotypes,mouse pathogenicity and other biological properties of the isolates were analyzed,and their 16S rDNA sequences and drug sensitivity were determined.As results,20 E.rhusiopathiae strains were isolated and identified,all of them were classified into serotype 1a in serum type,and an led to 100%mortality in challenged mice,i.e.,they had the biochemical characteristics of E.rhusiopathiae.The homology of 16S rDNA sequence with domestic reference strains and other clinical strains of E.rhusiopathiae was>99%.Using challenge with lethal dose of 5 field strains of E.rhusiopathiae by intraperitoneal inoculation,mice immunized with commercial attenuated vaccine of E.rhusiopathiae were 100%protected from the challenge.All isolated strains were sensitive to penicillin,ampicillin,erythromycin,tilmicosin,ceftriaxone,ceftiofur and florfenicol.However,there were multi-drug resistances to lincomamides,quinolones,aminoglycosides,tetracyclines,sulfonamides,and polypeptides at varied levels.In conclusion,this study clarified the biological characteristics and antibiotic resistance of E.rhusiopathiae in East China,and the current commercial attenuated vaccine of E.rhusiopathiae can completely protect the pigs from challenges with the tested strains,which provides data for the effective prevention and control of swine erysipelas in clinical practice.