胡子鲶致病性摩氏摩根菌的分离鉴定与致病性研究

本研究从患病胡子鲶体内分离得到一株菌,通过菌体形态观察、生理生化试验、16S rDNA分析及构建系统发育树对其进行分析,得出该致病菌为摩氏摩根菌。人工感染试验结果显示,该致病菌对胡子鲶具有较强的致病能力,同时对罗非鱼、泥鳅和禾花鲤也有很强的致病能力。药敏试验结果显示,KD01菌株对青霉素G、氨苄青霉素和新生霉素等药物有高度的耐药性,对复方新诺明、恩诺沙星和环丙沙星等药物敏感。本试验结果对胡子鲶出血性肠道坏死疾病研究提供有力的依据,同时可指导养殖户合理用药。     

蛋源摩氏摩根菌分离、鉴定及遗传进化分析

本研究利用传统细菌鉴定方法、革兰氏阴性细菌生化鉴定系统及16S rDNA 序列分析对分离自市售新鲜鸡蛋中的菌株进行形态学、培养特性及生化特性等生物学特性鉴定及遗传进化分析,结果表明分离株为摩氏摩根菌。药物敏感性试验结果表明,该菌株对痢特灵、利福平、四环素、磷霉素、多黏菌素B和阿奇霉素有耐药性,属于多重耐药菌株。序列分析结果显示,该分离菌株与目前已分离的其他食源性摩氏摩根菌菌株高度同源。     

斑点叉尾鮰套肠病病原嗜水气单胞菌的分离与鉴定

为确定疑似细菌感染的斑点叉尾鮰病原,本试验对临床病例进行细菌分离培养、生物化学鉴定和分子生物学鉴定、动物回归试验和病原菌药敏试验。结果显示,分离菌为革兰氏阴性杆菌,菌落形态和生化特性与嗜水气单胞菌相符;16S rDNA检测与测序分析结果进一步证实分离菌确为嗜水气单胞菌;动物回归试验显示,分离菌能引起与临床自然病例相似的症状;药敏试验显示,分离菌对喹诺酮类药物敏感,对青霉素类、头孢类药物产生耐药性。结果表明,疑似细菌感染斑点叉尾鮰病例为嗜水气单胞菌感染,可选择喹诺酮类药物进行病例的预防治疗。     

异育银鲫非O1/非O139群霍乱弧菌的分离及鉴定

为鉴定引起异育银鲫发病的疫情的病原,本研究从病鱼体内分离到细菌分离株,经动物回归试验证明为导致异育银鲫发病的致病原.对病原菌株进行形态学、生理生化测定以及16S rDNA序列分析,显示该菌株与霍乱弧菌(Vibrio cholerae)表型特征一致,而且在系统发育树中也是与霍乱弧菌相聚类,两者16S rDNA序列相似性高达99.93％.综合表型特征与基因序列分析的结果表明,该病原菌株应归属于霍乱弧菌.血清型鉴定为非O1/非O139群霍乱弧菌.药物敏感性试验结果显示该株霍乱弧菌对喹诺酮类、头孢类、氨基糖苷类、大环内酯类,四环素类以及β-内酰胺类等药物敏感.     

患病大鲵摩氏摩根菌的分离与鉴定

从患病大鲵肝脏中分离到1株优势菌SX01,通过Biolog微生物自动鉴定系统、16S rDNA序列分析及构建系统发育树的方法对纯培养的细菌进行鉴定,并进行人工感染试验及药敏试验。结果表明,该分离菌为摩氏摩根菌(Morganella morganii),对大鲵具有致病性。药物敏感性试验表明,该菌株对头孢曲松、头孢吡肟、氨曲南等10种药物高度敏感。     

水貂绿脓杆菌分离鉴定及药物敏感性分析

本试验旨在通过对山东某水貂养殖场送检的5只具有典型出血性肺炎症状的病死水貂进行细菌分离鉴定及耐药情况分析,为临床用药和治疗提供依据和参考。通过细菌分离纯化、生化鉴定和PCR方法对分离菌株进行鉴定,采用K-B药敏法检测分离菌株对常用药物的敏感性,并通过PCR方法检测分离菌株耐药基因的携带情况。经鉴定共分离得到5株绿脓杆菌,药物敏感性试验结果显示,5株绿脓杆菌对氟喹诺酮类药物、第3代和第4代头孢类药物较敏感,对氨基糖苷类、四环素、氯霉素、青霉素类、第1代和第2代头孢类药物耐药。耐药基因检测结果显示,5株绿脓杆菌共检测出6种耐药基因aadA1、aac(3')-Ⅱc、aac(6')-Ⅰb、tetA、tetK、cat2。且每株分离菌均检测出3种以上耐药基因。结果表明,分离的5株菌株均为绿脓杆菌,主要引起水貂出血性肺炎。分离菌株耐药性较严重,主要表现为多重耐药现象。菌株携带的耐药基因呈多样性,可引起菌株对相应药物产生耐药现象。     

猪葡萄球菌分离鉴定及药敏试验

为查明猪场仔猪渗出性皮炎的致病菌及确定其有效治疗药物,对病料进行细菌分离鉴定和药敏试验。从肺脏、心脏及病变皮肤等部位分离细菌后进行纯化,通过镜检、生化反应、细菌鉴定仪鉴定确定该致病菌为猪葡萄球菌;药敏试验结果表明,该菌对青霉素类、林可酰胺类、大环内酯类、氨基糖苷类、喹诺酮类、四环素类药物均耐药,对头孢类药物较敏感,建议用作仔猪渗出性皮炎的治疗。     

罗非鱼源无乳链球菌的分离鉴定及药敏试验

从广东省佛山市2个水产养殖场患病罗非鱼中分离到2株细菌,分别编号为T4SH和G6C,经形态学、培养特性观察、生化鉴定和16S rDNA基因序列分析证实为无乳链球菌。2株分离菌株均为革兰阳性菌,呈β溶血;16S rDNA基因序列与无乳链球菌同源性达99%以上。2株菌均对青霉素类、头孢类、林可胺类、大环内酯类、四环素类、氯霉素类抗生素敏感,对氨基糖苷类不敏感;而对磺胺类、喹诺酮类的敏感性存在差异。     

广西猪流产胎儿溶血葡萄球菌的分离鉴定及其16S rDNA基因系统进化分析

为了查清引起母猪流产的原因,从送检流产胎儿的内脏组织中分离培养细菌,对分离菌株进行革兰氏染色镜检、药敏试验、生化试验、16S rDNA基因序列测定、同源性分析及系统进化树构建。结果表明,分离菌株为革兰氏阳性球菌,其生长特性、菌落特征、生化试验鉴定结果基本符合《常见细菌系统鉴定手册》中溶血葡萄球菌的生化特性;但在血琼脂培养基上并未出现溶血现象。药敏试验结果表明,分离菌株仅对新生霉素、利福平和米诺环素敏感,对青霉素类、头孢类、氨基糖苷类、氟喹诺酮类等药物严重耐药。分离菌株16SrDNA基因与12株不同来源的溶血葡萄球菌同源性在99.8%～99.9%之间,与溶血葡萄球菌MER TA39菌株(KT719446.1)遗传进化距离最相近。小鼠致病性试验表明,分离菌株能导致小鼠出现行动迟缓、扎堆和被毛燥乱等临床症状,并能从小鼠体内分离出相同形态特征和菌体特征的菌株。表明从猪流产胎儿体内分离到的菌株是存在多重耐药性的γ-溶血葡萄球菌。     

鸡白痢沙门菌的分离鉴定与耐药性分析

对临床送检的疑似鸡白痢的病例进行细菌分离,采用PCR方法扩增沙门菌特异的invA基因,结合血清分型和生化鉴定,分析分离株对药物的耐药性。结果共分离出7株细菌,分离菌可以扩增出invA基因的目的条带,均与沙门菌O1、O9、O12因子血清发生凝集反应,不能发酵乳糖,能够发酵葡萄糖,不产生吲哚,与沙门菌菌株的生化反应基本相符。由此判定该分离菌为鸡白痢沙门菌。药敏试验结果显示,分离株对氨基糖苷类药物、喹诺酮类药物、β内酰胺类、酰胺醇类药物的敏感性较强,有4个分离株为多重耐药菌株。     

Isolation,Identification and Biological Characteristics Analysis of a Strain of Clinical Streptococcus suis Serotype 2

In order to determine the pathogen and its virulence characteristics of a suspected case of piglets streptococcosis in a pig farms in Jiangxi province during September to November of 2013,a strain was isolated from the joint fluid and cerebrospinal fluid of one diseased piglet.The isolated strain was identified by culture characteristics,biochemical test,16S rDNA sequence analysis,serotype PCR test and further studied the presence of the following virulence genes:Glutamate dehydrogenase (gdh),virulent-assocciated sequence (orf2),fibronectin-binding proteins (fbps),suilysin (sly),extracellular protein factor (epf),muramidase-released protein (mrp) and antibiotic sensitivity tests.The isolated strain was identified as Streptococcus suis serotype 2 by culture characteristics,biochemical test,16S rDNA sequence analysis and serotype PCR test,and it was named as JMS2. Detection results of virulence gene showed that the distribution of main virulence genes of JMS2 were gdh⁺/orf2⁺/fbps⁺/sly^-/epf^-/mrp^-,suggesting that the strain maybe not likely to be high virulence.Drug sensitivity tests showed that the JMS2 was susceptibility to β-lactams such as penicillin,amoxicillin,but resistant to azithromycin,SMZ-TMP,and so on.The result was significant for the clinical prevention and treatment of swine streptococcosis.     

Isolation,Identification and Pathogenicity Analysis of Morganella morganii in Clariasfuscus

In this study, we isolated a strain from diseased Clariasfuscus. Through morphological observation, physiological and biochemical tests, 16S rDNA and phylogenetic tree analysis method, it was concluded that the pathogen was Morganella morganii. Artificial infection experiment results showed that the pathogen had strong pathogenicity to Clariasfuscus, and also had strong pathogenicity to totilapia, loach and carp.The drug sensitivity test results showed that the KD01 strains had high resistance to 6 medicines, including penicillin G, ampicillin and novobiocin, and so on. And it had the sensitivity to the 15 medicines, including chemitrim, enrofloxacin and ciprofloxacin, and so on.The test results of hemorrhage of intestinal necrosis disease study provided a strong basis for the study of Clariasfuscus, also could guide farmers to the rational use of drugs.     

黄颡鱼迟钝爱德华菌的分离鉴定及其致病性研究

为了确定黄颡鱼发病的原因,试验从患病黄颡鱼体内分离得到1株病原菌,命名为GDYM20160809,通过形态学观察、生理生化特性鉴定、16S rDNA分析及系统进化树构建等方法对分离菌进行鉴定,采用滤纸片扩散法对分离菌进行药敏试验。结果显示,该分离菌为革兰氏阴性短杆菌,PCR扩增其16S rDNA片段,经测序及BLAST比对,显示其与迟钝爱德华菌（Edwardsiella tarda）的同源性达100%,结合生理生化鉴定结果确定分离菌为迟钝爱德华菌。药敏试验结果显示,分离菌对磺胺类药物、头孢类药物、青霉素、复方新诺明等药物敏感,对磺胺间甲氧嘧啶钠、新生霉素、多黏菌素B、阿米卡星、卡那霉素和万古霉素6种药物耐药;人工感染试验结果证实,菌株对罗非鱼、禾花鲤、草鱼和黄颡鱼都有很强的致病性。本试验结果为有效防控黄颡鱼细菌性疾病提供了理论依据,并可指导养殖户合理用药。     

Antimicrobial susceptibility of Edwardsiella tarda from the United States and Taiwan

Edwardsiella tarda isolates from the United States and Taiwan were screened against 37 antimicrobial agents. These isolates were highly susceptible to the amino-glycosides, second and third generation cephalosporins, newer penicillins, nitrofurantoin, sulfamethoxazole/trimethoprim, and the quinolones. Source-related resistance was found for penicillin G, sulfadiazine, colistin, novobiocin, spectinomycin, ampicillin, tetracycline, and chloramphenicol. Generally, the Taiwan isolates were more resistant than the United States isolates.     

一株草鱼维氏气单胞菌的分离鉴定及毒力基因分析

为了鉴定贵州芩巩县某养殖场草鱼发病死亡的病原,本研究通过临床解剖观察、细菌分离培养、革兰氏染色镜检、生化鉴定、药敏试验、动物回归试验、16S rDNA与gyr B基因测序及系统分析进行鉴定。结果显示,本研究从发病草鱼体内分离到1株致病菌GZQG2019,分离菌在培养基中呈圆形、表面湿润光滑、边缘整齐半透明的灰白色菌落,菌落周围呈现β-溶血环;革兰氏镜检显示,分离菌呈两端钝圆短小阴性杆菌;16S rDNA、gyr B基因序列分析显示,分离菌与维氏气单胞菌聚为一支,同源性均在99%以上;药敏试验结果显示,在使用的20种抗菌药物中,该菌对四环素、丁胺卡那、多黏菌素B和头孢曲松等10种药物敏感,对苯唑西林、青霉素、阿莫西林和庆大霉素等8种药物中度敏感,对头孢氨苄、复方新诺明2种药物耐药;动物回归试验显示,该菌对健康草鱼具有强致病性;10种毒力基因扩增结果显示,分离菌携带气溶素、热不稳定性肠毒素、溶血素、核酶、丝氨酸蛋白酶、弹性蛋白酶和酯酶7种毒力基因。本试验成功分离到1株草鱼源维氏气单胞菌,具有较强毒力,且携带多种毒力因子;对四环素、丁胺卡那等药物敏感,对四环素、丁胺卡那等耐药,为维氏气单胞菌病临床用药提供参考依据。     

鱼源蜡样芽孢杆菌的分离鉴定及耐药性分析

为探究鱼源蜡样芽孢杆菌的致病性和耐药性及指导科学用药,本试验采用形态学观察、生理生化特性分析、16S rDNA基因扩增及系统进化树构建等方法鉴定分离菌,人工感染试验确定分离菌的致病性,耐药基因检测和药敏试验确定菌株耐药性。结果显示,分离菌株形成边缘不规则、不光滑的乳白色菌落,为需氧型革兰氏阳性菌。葡萄糖、硝酸盐、明胶液化等生化反应为阳性,木糖、阿拉伯糖、甘露醇等生化反应为阴性。16S rDNA基因片段长度为1 457 bp,在系统发育树中,分离菌与蜡样芽孢杆菌RTR菌株亲缘关系最近,与蜡样芽孢杆菌的同源性均达到99%以上,从而综合判定分离菌株为蜡样芽孢杆菌。人工感染试验发现,分离菌株对黄颡鱼有一定的致病性。耐药基因检测结果显示,分离菌株中检测出Sul1和Sul2两种耐药基因。药敏试验发现,该菌株对庆大霉素、哌拉西林、米诺环素等敏感,对头孢哌酮中度敏感,对青霉素、头孢曲松、氨苄西林等耐药。本试验结果为有效防控蜡样芽孢杆菌感染的疾病提供了科学参考资料。     

1株鸭源奇异变形杆菌的分离鉴定与毒力基因检测

试验旨在研究鸭源分离菌的耐药性及致病性,通过细菌分离鉴定、药敏试验、耐药基因和毒力基因PCR检测及动物致病性试验,成功分离到1株细菌,经纯化和革兰氏染色,显微镜下显示两种形态：短杆状以及细长如发丝,革兰氏染色为阴性菌,将其命名为GZGY2020。生化反应显示,分离菌具有明显的运动性,M-R试验、V-P试验均为阳性,生化特性符合奇异变形杆菌。分离菌16S rDNA进化树结果显示,其与奇异变形杆菌处于同一分支。药敏试验结果发现,分离菌对多种药物耐药,对18种药敏纸片中羧苄西林、头孢氨苄、苯唑西林等16种药物耐药,耐药率高达88.9%,仅对头孢他啶和环丙沙星敏感;PCR检测其含有磺胺类耐药基因基因sul1和sul2及β-内酰胺类耐药基因VIM,并含有hpmA、rsmA、atfA、ucaA、ureC、zapA、pmfA、fliL和mrpA 9种毒力基因。动物回归试验结果显示,分离菌对雏鸭致病力强,即1×10⁸ CFU/mL菌液能使雏鸭1 d内全部死亡。在药敏特性上,从病死鸭中分离到的菌株GZGY2020与以往报道的奇异变形杆菌有一定差异,表明该菌可能发生变异,导致毒力增强,而检测的10种毒力基因中仅有1种毒力基因没有出现相应的条带,表明奇异变形杆菌是引起该鸭死亡的重要致病菌,应引起高度重视。     

3株维氏气单胞菌耐药性及毒力基因的比较

为探究不同地区的维氏气单胞菌（Aeromonas veronii）耐药性及毒力基因是否存在区别,本研究从生长形态、生化试验、药敏试验、人工感染试验、16S rDNA基因测序同源性分析及毒力基因等方面比较了草鱼源菌株GZCY2019、杂交鲟源菌株GZXY2018及斑点叉尾鮰源菌株GZBD2017的差异。结果显示,3株不同源维氏气单胞菌在鲜血平板上均为圆形、表面湿润光滑、边缘整齐半透明的灰白色菌落,菌落周围均有β溶血环;革兰氏染色镜检均为两端钝圆短小阴性杆菌;药敏试验显示,3株菌对丁胺卡那、多西环素等药物均敏感,而对复方新诺明、头孢他啶、多黏菌素B等药物均中度敏感,对其他药物则表现出不同程度的敏感性或者耐药性;人工感染试验显示,菌株GZCY2019与GZBD2017对小鼠累计死亡率为100%,菌株GZXY2018的累计死亡率为80%;16S rDNA同源性分析显示,菌株GZCY2019与菌株GZBD2017同源性为99.9%,二者与菌株GZXY2018同源性均为97.1%;毒力基因检测结果显示,3株菌均携带热不稳定性肠毒素（Alt）、溶血素（hlyA）与鞭毛（Fla）等毒力基因,而对细胞毒性肠毒素（Act）及其热稳定性肠毒素（Ast）毒力基因的携带则表现不同。本研究通过不同源维氏气单胞菌的对比发现,3株菌在生长形态、染色镜检结果、生化结果上基本相似,但耐药性和毒力基因的携带存在较大差异。     

Comparison of Drug Resistance and Virulence Genes of Three Strains of Aeromonas veronii

To find out whether there were differences in drug resistance and virulence genes of Aeromonas veronii (A.veronii) from different regions,this study compared morphology,biochemistry test,drug sensitive test,artificial infection test,16S rDNA gene sequencing and virulence genes homology analysis for grass carp source strain GZCY2019,hybrid sturgeon source strain GZXY2018 and Ictalurus punctatus source strain GZBD2017.The results showed that all the three strains of A.veronii from different sources presented round,moist and smooth gray and translucent colonies with neat edges on the blood plate,and the colonies were surrounded by β hemolytic rings.Gram staining showed that negative Bacillus crassus at both ends.Drug sensitivity test showed that the three strains were all sensitive to butylaminacana,doxycycline,but were all intermediary to compound xinnomin,ceftadime,polymyxin B and other drugs,while were at different degrees of sensitivity or resistance to other drugs.Artificial infection test showed that the cumulative death rates of GZCY2019 and GZBD2017 were both 100%,while the rate of GZXY2018 was 80%.The homology analysis of 16S rDNA showed that the homology between GZCY2019 and GZBD2017 was 99.9%,while the homology between the former two strains and GZXY2018 was 97.1%.Virulence gene test results showed that Alt,hlyA and Fla virulence genes were all carried,while cytotoxic enterotoxin Act and Ast virulence genes were different.In this study,through comparison of multiple experiments with different sources of A.veronii,it was found that the three strains were basically similar in growth morphology,staining microscopy and biochemical results,but there were significant differences in resistance and virulence genes.