念珠状链杆菌在小鼠群中的自然感染和发病特征的观察

本文在国内首次报告了念珠状链杆菌在清洁级Ｃ５７ＢＬ／６Ｊ小鼠群中的自然感染,并从临床、病理解剖、病原学及流行病学方面进行了较为详细的观察,在受检的１４例发病动物中,颈部淋巴结肿大、化脓占７１．４％,皮下、肺门淋巴结脓肿分别占５０．０％和２１．４％,多发性关节炎（包括趾、跗关节）占２１．４％,子宫积脓占７．１％,从所有病灶及部分动物的血液、脾、肝、肺、肾均分离到了单一的细菌。该菌在小鼠成功地进行了急性感染实验,受感染动物出现了典型的念珠状链杆菌病的临床及病理特征,即败血症、关节炎、淤血、水肿、紫绀、结膜炎等。所分离的致病菌在病原学上也完全符合念珠状链杆菌的病原学特征。在饲养环境上与发病鼠群有密切关系的其它４个品系小鼠群,即６１５、ＢＡＬＢ／ｃ、ＣＢＡ、ＫＭ,均未波感染,证明在对该菌的易感性方面存在品系差异。     

念珠状链杆菌的研究现状

念珠状链杆菌是人类鼠咬热及哈佛山热的主要致病菌,对人和实验小鼠等温血类动物有极强的致病性。近年来,随着城市范围的扩大、宠物种类的增多,被其感染而发病的人数也逐渐增加,尤其是对于生物医学实验工作者来说,该菌已被认为是一种职业危害。为此,部分发达国家已将该菌的感染列为新发感染性疾病的范畴。本文将就其生物学特性、致病性、实验室诊断及流行病学特征等方面的研究现状做一简要综述。     

不同品系小鼠对炭疽芽胞杆菌弱毒株芽胞的敏感性研究

通过比较四种品系小鼠对炭疽芽胞杆菌（Bacillus anthracis）（简称炭疽杆菌）弱毒株芽胞的敏感性，确定炭疽杆菌弱毒株芽胞攻毒合适的动物模型。采用炭疽杆菌弱毒株A16Q1（pXO1-、pXO2+）和A16PI2（pXO1+、pXO2-）的芽胞对四种品系小鼠（DBA/2、KM、ICR和BALB/c）进行腹腔攻毒，记录小鼠死亡时间，计算LD₅₀、绘制存活曲线并统计分析。运用较敏感的KM小鼠研究不同canSNP基因型毒素缺陷株（含pXO2拷贝数不同）芽胞的毒力差异。利用更为敏感的DBA/2小鼠评价S-层蛋白BA3338对荚膜缺陷株芽胞毒力的影响。结果表明，在四种品系小鼠中，毒素缺陷株芽胞的毒力均高于荚膜缺陷株芽胞的毒力。DBA/2小鼠对炭疽杆菌弱毒株芽胞的剂量依赖关系最好，最为敏感，其次是KM小鼠，而ICR小鼠和BALB/c小鼠对炭疽杆菌弱毒株芽胞不敏感。确定了DBA/2小鼠和KM小鼠在炭疽杆菌弱毒株芽胞研究中的适用性。使用KM小鼠评价了不同canSNP基因型炭疽杆菌芽胞的毒力差异，结果表明，不同canSNP基因型炭疽杆菌由于所含pXO2质粒拷贝数的差异导致芽胞的毒力不同。使用DBA/2小鼠评价了S-层蛋白BA3338缺失对炭疽杆菌芽胞毒力的影响，表明BA3338基因的缺失导致炭疽杆菌芽胞毒力降低。     

不同品系实验小鼠6种脱氢酶同工酶的比较研究

本文采用0.5mm超薄层水平板状聚丙烯酰胺凝胶等电聚焦技术,对A/wy,AKR/J,A2G/J,BALB/cA,CBA/N,C3H/HeJ,C57BL/6N,DBA/2J,129/J等9个近交系小鼠品系的MEs,MEm,ADH,LDH,MDHs,MDHm等6种脱氢酶同工酶作了等电点测定和分析。依据等电聚焦酶谱,比较研究了酶谱类型和酶活性差异与代谢功能的关系以及与基因变异的关系。结果显示:ADH-r1酶谱型为对乙醇低氧化能力型,ADH-r2酶谱型为对乙醇高氧化能力型。C57BL/6N的胃ADH同工酶谱与众不同,特征酶带p16.87为r2型,属酒精高嗜性品系;其余品系的胃ADH同工酶谱为ADH-r1型,均为酒精低嗜性品系。DBA/2J的肾MDHs同工酶谱为基因变异引起酶活性改变的类型,其中p14.90,p14.99,p15.05等 3条酶带较其它品系的同位酶带活性高,由此推断DBA/2J的肾具有更强的糖异生能力和机体抗饥饿能力。 LDH同工酶等电聚交酶谱表现出极丰富的多态性,鉴于LDH在生物进化中具有的重要地位,作者认为LDH可作为实验动物育种、保种、野生动物实验动物化遗传质量监测的生化标志基因临界位点。超薄层等电聚焦技术具有其它电泳所不具备的优点,作为实验动物遗传质量监测技术更其精确性,值得推荐。     

空肠弯曲杆菌感染小鼠模型的研究进展

空肠弯曲杆菌主要导致食源性胃肠疾病,对人类健康有重要影响,然而相关小鼠感染模型的建立是该致病菌研究的难点.本文综述了影响空肠弯曲杆菌感染模型建立的关键因素,包括菌株的毒力因子、小鼠的品系、免疫功能、肠道菌群、饮食组成、宿主适应等因素,以期为成功建立合适的小鼠感染模型提供参考.     

我国实验小鼠群中巨细胞病毒自然感染情况的调查

迄今为止,有关MCMV在实验小鼠群中的自然感染情况报道极少。我们在MCMV实验感染的基础上对国内常用的小鼠品系进行MCMV自然感染的调查。结果发现在334份不同品系小鼠颌下腺中无1份分离出MCMV,而特异性抗体存在于所检查的10个品系中,阳性率为10.9—87.5％。抗体阳性率与鼠龄有关,随鼠龄的增长而上升。对全国部分省市40家实验动物机构的556份小鼠血清的调查结果表明MCMV的抗体阳性率达61.0％,提示在我国实验小鼠群中MCMV的自物感染是相当普遍的。这种病毒分离阴性而抗体阳性的状态表明隐性感染和潜伏感染是MCMV自然感染的主要方式。     

两种品系小鼠对日本血吸虫感染及肿节风处理反应的比较

本实验对BALB/c近交鼠及昆明小鼠感染日本血吸虫及肿节风处理后的反应,对血吸虫的生物学特性及宿主的若干反应作了比较研究,区分了它们充作日本血吸虫终末宿主的特点。认为,在缺乏更适宜的近交鼠的情况下,昆明小鼠不失为一种较好的日本血吸虫感染的动物模型。 .     

乳杆菌DM8909菌株抑制小鼠阴道感染的研究

目的 :探讨乳杆菌 DM880 9菌株对小鼠阴道内其他菌群的抑制及调整阴道菌群的作用。方法 :通过用阿莫西林钠溶液对小鼠阴道冲洗处理后 ,接种致病性大肠埃希菌 EPEC10 4 ,建立起大肠埃希菌在小鼠阴道内的定植 ;用乳杆菌 DM890 9菌液冲洗治疗来去除大肠埃希菌 EPEC10 4在小鼠阴道的定植。结果 :通过各组小鼠阴道冲洗液检出的平均对数值比较 ,乳杆菌治疗组的小鼠阴道内大肠埃希菌的数量 ( 3.82±0 .6 2 )较自然恢复组小鼠阴道内大肠埃希菌的数量 ( 6 .72± 1.16 )减少明显 ( P<0 .0 5 ) ,而且治疗组的症状好转率 ( 8/10 )显著好于自然恢复组的症状好转率 ( 2 /10 ) ( P<0 .0 5 )。结论 :乳杆菌 DM890 9菌株能有效去除大肠埃希菌 EPEC10 4在小鼠阴道的定植和改善小鼠外阴的炎症症状     

反刍兽源附红细胞体感染小鼠的研究

目的　采用反刍兽源附红细胞体感染小鼠 ,研究附红细胞体的感染途径及在小鼠体内的消长规律 ,试图建立附红细胞体感染动物模型。方法　经小鼠腹腔、皮下接种含有附红细胞体的奶牛、山羊血液 ,脏器悬液和接触感染。结果　四种接种方法均获成功 ,附红细胞体在小鼠体内呈现一定的规律性。感染后第 8天附红细胞体在小鼠的血液可以查见。感染后第 15～ 18天附红细胞体的感染率达到高峰。感染后第 2 0d附红细胞体逐渐消失。在整个实验过程中未见感染小鼠明显的临床症状。结论　可以用小鼠建立附红细胞体感染动物模型。附红细胞体的感染方式有以下几种 :腹腔、皮下接种、接触感染。     

Focus: Zoonotic Disease: Prevalence and Diversity of the Streptobacillus Rat-bite Fever Agent,in Three Invasive,Commensal Rattus Species from South Africa

Rat-bite fever is an over-looked, global zoonotic disease that has a mortality rate of up to 13%, if untreated. Historically, this rat-borne disease has been attributed to one of two causative agents, Streptobacillus moniliformis or Spirillum minus. Given the confirmed presence of multiple invasive Rattus host species, high rat densities in urban, informal human settlements and increasing reports of rat bites in South Africa, we undertook a retrospective assessment of Streptobacillus in rats sampled from 16 urban sites, in Gauteng, the smallest but most populous Province in South Africa. Using a multi-gene PCR-sequencing approach, we confirmed Streptobacillus presence in 50.9% of oral swabs from three rat species and the presence of two Streptobacillus species, viz. S. moniliformis and S. notomytis. The two members of the cryptic Rattus rattus species complex (R. rattus and R. tanezumi), which are morphologically indistinguishable from each other, had markedly different colonization rates. Whereas 48.6% of rats from this species complex were Streptobacillus-positive, only 32.3% of Rattus tanezumi were positive compared to 61.5% R. rattus. Rattus norvegicus had an intermediate prevalence of 55.6%. Phylogenetic analysis of four gene regions (16S rRNA, gyrB, groEL, recA) identified two discrete lineages; S. moniliformis occurred exclusively in R. norvegicus, and S. notomytis was restricted to the two members of the R. rattus species complex; this represents the first report of Streptobacillus in R. tanezumi. These results highlight a largely overlooked zoonotic threat posed by invasive rats and confirm the presence of two discrete and potentially host-specific Streptobacillus lineages in South Africa.     

肾综合征出血热病毒对不同生理状态小鼠的实验感染及在小鼠淋巴细胞亚群中的定位

本文用双标记免疫细胞化学和双标记免疫电镜技术观察了环磷酰胺处理的BALB/c小鼠及乳鼠实验感染肾综合征出血热病毒后的发病和病毒定位情况,结果发现,免疫功能不成熟或有缺陷的小鼠感染后发病并有规律地死亡,而免疫功能正常鼠只呈隐性感染。在发病的和隐性感染的小鼠之间,病毒定位主要差别在于HFRSV是否感染免疫器官,即HFRSV抗原可见于发病鼠外周血,牌和胸腺的单个核细胞中,而在隐性感染小鼠的这些免疫器官中则为阴性,HFRS病毒颗粒及病毒抗原广泛见于发病鼠的T细胞亚群中,在Thy-1,L3T4和Lyt-2亚群中,双标记阳性细胞百分比分别为24.6+—15.3％,7.5％+—6.1％和17.7+—6.1％。对HFRSV在T细胞中分布的差异还作了动态比较。结果提示:细胞免疫可受HFRSV的直接影响,病毒对宿主免疫系统的感染是HFRSV感染发病的一个关键因素。     

Detection of antibodies to Streptobacillus moniliformis in rats by an immunoblot procedure

An immunoblot (IB) technique for detecting antibodies to Streptobacillus moniliformis in rat sera was evaluated. Immune sera to three S. moniliformis strains showed a similar reactivity pattern with both autologous and homologous antigens in the 18-87 kDa range. Using a rat S. moniliformis strain as the antigen, a similar reactivity pattern was found with sera from rats infected experimentally with S. moniliformis and sentinels. Two to five proteins were detected in the 32-55 kDa range. Over a period of 2.5 years, 27/133 rat serum panels submitted for routine monitoring yielded one or more S. moniliformis enzyme-linked immunosorbent assay (ELISA)-positive samples. In one of these 27 panels, sera showed an IB reactivity pattern resembling that observed with immune sera and with sera from infected and exposed rats. S. moniliformis was confirmed in the colony by both culture and polymerase chain reaction (PCR). Sera from the remaining 26 ELISA-positive serum panels frequently showed activity to a 57 kDa antigen but not more than one antigen was detected in the 32-55 kDa range. We conclude that the IB can be used as a confirmatory test for the detection of S. moniliformis infection in ELISA-positive rats.     

Circadian Variations in Coagulation and Fibrinolytic Factors among Four Different Strains of Mice

This study examined circadian variation in coagulation and fibrinolytic parameters among Jcl:ICR, C3H/HeN, BALB/cA, and C57BL/6J strains of mice. Plasma plasminogen activator inhibitor 1 (PAI‐1) levels fluctuated in a circadian manner and peaked in accordance with the mRNA levels at the start of the active phase in all strains. Fibrinogen mRNA levels peaked at the start of rest periods in all strains, although plasma fibrinogen levels remained constant. Strain differences in plasma antithrombin (AT) activity and protein C (PC) levels were then identified. Plasma AT activity was circadian rhythmic only in Jcl:ICR, but not in other strains, although the mRNA levels remained constant in all strains. Levels of plasma PC and its mRNA fluctuated in a circadian manner only in Jcl:ICR mice, whereas those of plasma prothrombin, factor X, factor VII, prothrombin time (PT), and activated partial thrombin time (APTT) remained constant in all strains. These results suggest that genetic heterogeneity underlies phenotypic variations in the circadian rhythmicity of blood coagulation and fibrinolysis. The circadian onset of thrombotic events might be due in part to the rhythmic gene expression of coagulation and fibrinolytic factors. The present study provides fundamental information about mouse strains that will help to understand the circadian variation in blood coagulation and fibrinolysis.     

Experimental Infection with Pseudomonas aeruginosa in Mice

Comparative studies on the virulence of 22 clinical isolates of Pseudomonas aeruginosa were made by means of intraperitoneal inoculation in mice. The LD₅₀ values of these strains for mice ranged from 10^{5 0} to 10^7.5 viable cells per mouse and the average was 10^6.6. The virulence of certain strains was significantly enhanced when these strains were inoculated mixed with mucin. The highly virulent strains were often found among the strains which were serologically untypable though no relationship could be found between the virulence of test strains and their other biological characteristics such as pigments, hemolysins and extracellular enzymes. The facts suggest that pigments and extracellular enzymes play no important role in the pathogenicity of P. aeruginosa for mice. Moreover, no difference was seen on virulence among the strains isolated from the patients and healthy carriers. The susceptibility of ICR, ddN and CF#1 mice for P. aeruginosa was investigated. There was no clear difference in susceptibilities to P. aeruginosa infection.