[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determinati...[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determination of growth curve and correlation curve between OD 600 values and viable counts,drug susceptibility tests,pathogenicity analysis,and histopathological observations were carried out.[Results]The Streptococcus strain isolated from infected pigs was identified as Streptococcus suis type 2,which was named TA01 strain.TA01 strain reached the growth peak at 6-8 h post-incubation,and viable counts gradually declined after 8 h of incubation.The correlation equation between OD 600 values and viable counts is y=24.659 x-1.076 1,R^2=0.996 7.TA01 strain was sensitive to penicillin,erythromycin,florfenicol and oxacillin,and resistant to ciprofloxacin,polymyxin B and clindamycin.According to the results of pathogenicity analysis,all the mice in 3.6×10^9 cfu/mouse group died within 48,and these dead mice exhibited acute pyaemia septica.Based on the Reed-Muench formula,it was calculated that LD 50 of TA01 strain was 1.137×10^8 cfu/mouse.Pathological examination showed obvious blue-stained bacteria clusters,accompanied by neutrophil infiltration.[Conclusions]TA01 strain was a virulent strain of Streptococcus suis type 2.Compared with Streptococcus strains which were isolated and reported in China,TA01 strain exhibited strong virulence and rapid proliferation.展开更多
White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers, samples such as livers ...White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers, samples such as livers and joint pus were collected from dead broilers under sterile condition, and one pathogenic strain was isolated. The isolate was identified to be Staphylococcus aureus through isolated culture, morphologic observation, inspection of biochemical property and animal test. The drug sensitivity test showed that the isolate was sensitive to ceftazidime, enrofloxacin, ceftriaxone, lincomycin and amikacin, but resistant to other drugs to different degrees.展开更多
从一例疑似沙门氏菌感染的发病鸡只中分离到一株细菌,对其进行培养特征、革兰氏染色、生化试验以及16S r DNA序列分析,并进一步对分离菌进行药敏试验。结果显示,该分离细菌在鲜血琼脂培养基中生长出灰白色、圆形、光滑、凸起的菌落,在S...从一例疑似沙门氏菌感染的发病鸡只中分离到一株细菌,对其进行培养特征、革兰氏染色、生化试验以及16S r DNA序列分析,并进一步对分离菌进行药敏试验。结果显示,该分离细菌在鲜血琼脂培养基中生长出灰白色、圆形、光滑、凸起的菌落,在SS琼脂培养基表现为中心黑色边缘半透明、圆形光滑菌落。革兰氏染色后可见革兰氏阴性短杆菌。生理生化试验结果符合沙门氏菌特征。PCR扩增出717 bp条带,经测序对比,与沙门氏菌基因同源性最高。药敏结果显示分离菌仅对头孢他啶表现敏感,对氨曲南表现中度敏感,对庆大霉素、新霉素等14种药物均表现为耐药。本研究为该地区沙门氏菌病的防治提供一定的参考。展开更多
基金Supported by National Key Basic Research Program of China(973 Program)(2017YFD0500605)
文摘[Objectives]This study aimed to investigate the pathogenicity,growth characteristics and drug resistance of Streptococcus suis type 2.[Methods]Bacterial isolation and identification,biochemical experiments,determination of growth curve and correlation curve between OD 600 values and viable counts,drug susceptibility tests,pathogenicity analysis,and histopathological observations were carried out.[Results]The Streptococcus strain isolated from infected pigs was identified as Streptococcus suis type 2,which was named TA01 strain.TA01 strain reached the growth peak at 6-8 h post-incubation,and viable counts gradually declined after 8 h of incubation.The correlation equation between OD 600 values and viable counts is y=24.659 x-1.076 1,R^2=0.996 7.TA01 strain was sensitive to penicillin,erythromycin,florfenicol and oxacillin,and resistant to ciprofloxacin,polymyxin B and clindamycin.According to the results of pathogenicity analysis,all the mice in 3.6×10^9 cfu/mouse group died within 48,and these dead mice exhibited acute pyaemia septica.Based on the Reed-Muench formula,it was calculated that LD 50 of TA01 strain was 1.137×10^8 cfu/mouse.Pathological examination showed obvious blue-stained bacteria clusters,accompanied by neutrophil infiltration.[Conclusions]TA01 strain was a virulent strain of Streptococcus suis type 2.Compared with Streptococcus strains which were isolated and reported in China,TA01 strain exhibited strong virulence and rapid proliferation.
基金Supported by Hebei Science and Technology Deparment Project(17226607D)
文摘White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers, samples such as livers and joint pus were collected from dead broilers under sterile condition, and one pathogenic strain was isolated. The isolate was identified to be Staphylococcus aureus through isolated culture, morphologic observation, inspection of biochemical property and animal test. The drug sensitivity test showed that the isolate was sensitive to ceftazidime, enrofloxacin, ceftriaxone, lincomycin and amikacin, but resistant to other drugs to different degrees.
文摘从一例疑似沙门氏菌感染的发病鸡只中分离到一株细菌,对其进行培养特征、革兰氏染色、生化试验以及16S r DNA序列分析,并进一步对分离菌进行药敏试验。结果显示,该分离细菌在鲜血琼脂培养基中生长出灰白色、圆形、光滑、凸起的菌落,在SS琼脂培养基表现为中心黑色边缘半透明、圆形光滑菌落。革兰氏染色后可见革兰氏阴性短杆菌。生理生化试验结果符合沙门氏菌特征。PCR扩增出717 bp条带,经测序对比,与沙门氏菌基因同源性最高。药敏结果显示分离菌仅对头孢他啶表现敏感,对氨曲南表现中度敏感,对庆大霉素、新霉素等14种药物均表现为耐药。本研究为该地区沙门氏菌病的防治提供一定的参考。
