Experimental tuberculosis in the European badger (Meles meles) after endobronchial inoculation of Mycobacterium bovis: I. Pathology and bacteriology

The aim was to develop an endobronchial infection procedure for the study of Mycobacterium bovis infection in badgers. The badgers were anaesthetised and a cannula was passed per os to the tracheal bifurcation. When in place 1 ml of M. bovis suspension was inoculated. Three concentrations of M. bovis suspension were used; <10 colony forming units (cfu), approximately 10(2) cfu and approximately 3 x 10(3) cfu. The badgers were examined at three weekly intervals for clinical signs of disease and a tracheal aspirate was collected at each examination. The badgers were euthanased 17 weeks post infection (pi) and at the post mortem examination a wide range of tissues were examined for gross and histopathological lesions of tuberculosis and cultured for M. bovis. A sample of bronchial alveolar lavage (BAL) fluid was collected at post mortem for culture. At post mortem examination 17 weeks after infection, gross and histopathological lesions of tuberculosis were observed in all badgers inoculated with the high and medium dose and 1/3 inoculated with the low dose. M. bovis was recovered from all inoculated badgers. Infection in the high dose group was more widely disseminated than in the other groups. The number of sites with gross and histopathological lesions increased with increasing dose of M. bovis. All tracheal aspirates were negative on culture and only one BAL, collected from a badger of the high dose group, was positive on culture. No clinical signs due to the experimental infection were observed. The endobronchial route of inoculation is an effective route for establishing experimental infection, and could be used for studies of tuberculosis pathogenesis, immunology of M. bovis infection in badgers and for challenging badgers in vaccine protection studies. Badgers appeared to be very susceptible to infection by this procedure even with a dose of < 10 cfu but appear to control and limit the resulting infection.     

水貂源牛分枝杆菌的分离与荧光PCR鉴定

目的探讨水貂源结核杆菌复合群的检测方法,并进行病原学调查。方法利用7H10培养基分离水貂结核病的病原,采用荧光探针PCR方法进行检测。结果经鉴定分离的病原菌为致病性牛分枝杆菌。结论通过荧光探针PCR能够直接对结核杆菌复合群进行亚种鉴定,该方法具有快速、敏感、特异性强的优点,能够减少动物检疫时间。     

Estimates of within-herd incidence rates of Mycobacterium bovis in Canadian cattle and cervids between 1985 and 1994

We analysed the individual-animal data from six of the nine outbreaks of tuberculosis in Canadian cattle and cervids from 1985 to 1994. A “positive/reactor” animal was one which had either a positive culture or a positive or suspicious reaction on a mid-cervical, comparative cervical, or gross or histopathological test for tuberculosis. Individual-animal data were collected only for herds which had one or more positive/reactor animals. Data were collected from the outbreak records in the Regional or District offices of Agriculture and Agri-food Canada’s Animal and Plant Health Directorate. The within-herd spread of Mycobacterium bovis was studied by determining the most-likely date at which the herd was first exposed to M. bovis and the number of reactions which had developed by the time the herd was investigated. The animal-time units at risk in the herd were probably overestimated, resulting in conservative estimates of the within-herd incidence rates. Negative-binomial regression was used to investigate factors which might have influenced the within-herd spread of tuberculosis. Increasing age appeared to be a risk factor for being a positive/reactor animal. When compared to animals 0–12 months old, animals 13–24 months old had an incidence rate ratio (IRR) of 7.6, while animals >24 months old had an IRR of 10.4 (p=0.009). Actual and predicted incidence rates for tuberculosis in mature (>24 months old) animals were calculated. Actual and predicted incidence rates were similar for cervids, within an outbreak. There was more variability between actual and predicted rates in the dairy and beef animals. In the one outbreak (Ontario) where there were positive/reactor cervid, dairy and beef herds, the actual incidence rate for cervids (IR=9.3 cases per 100 animal-years) was almost twice that of dairy cattle (IR=5.0) and three times that of beef cattle (IR=3.1).     

抗结核药物及其应用研究

近年来,结核病重新在全球肆虐,艾滋病加速了结核病的流行,对多种药物具有耐药性的结核杆菌的蔓延,迫切需要研制新的高效抗结核药物．对抗结核药物的研究状况进行了论述,简单地回顾了现有的抗结核药物,对新型的抗结核药物进行了介绍,重点阐述了抗结核中药的研究及应用．     

结核分支杆菌耐药机制的研究

结核分支杆菌（结核杆菌,Mycobacterium TuberculoSiS,M．TB）已经对多种药物产生耐药性,使得对结核病的治疗无效或者疗效降低,导致近年来结核病的发病率呈上升趋势。本文综述了结合分支杆菌对几种药物产生的耐药性的机理。     

牛结核分枝杆菌PCR检测方法的建立

随着牛结核病疫情日趋严重,快速、高效的分子生物学检测方法建立显得十分必要.试验设计合成了牛结核分枝杆菌特异性引物,优化反应条件,建立了牛分枝杆菌PCR检测方法.结果显示,所建立的牛结核分枝杆菌PCR检测方法可有效检测牛结核分枝杆菌,在模板浓度、引物浓度和退火温度分别为1.32 μg/mL、0.5 μm/L、54℃时最佳;性能评估显示,该方法具有较好的特异性、敏感性和临床应用性,为我省牛结核病的综合防控提供关键技术.     

Drug resistant Tuberculosis: A review

Tuberculosis (TB) was announced as a global emergency in 1993. There was an alarming counter attack of TB worldwide. However, when it was known that TB can be cured completely, the general public became ignorant towards the infection. The pathogenic organism Mycobacterium tuberculosis continuously evolved to resist the antagonist drugs. This has led to the outbreak of resistant strain that gave rise to “Multi Drug Resistant-Tuberculosis” and “Extensively Drug Resistant Tuberculosis” that can still be cured with a lower success rate. While the mechanism of resistance proceeds further, it ultimately causes unmanageable totally drug resistant TB (TDR-TB). Studying the molecular mechanisms underlying the resistance to drugs would help us grasp the genetics and pathophysiology of the disease. In this review, we present the molecular mechanisms behind Mycobacterium tolerance to drugs and their approach towards the development of multi-drug resistant, extremely drug resistant and totally drug resistant TB.     

奶牛结核病的PCR检测方法的建立及应用

根据PCR技术的原理建立了奶牛结核病的PCR诊断方法,并测定出该方法的敏感性为30.9pg/ūL。特异性试验结果表明,除牛结核分枝杆菌的特异扩增带(242bp)外,其他的细菌均未出现特异性扩增带。用该方法对陕西省某奶牛养殖小区的121份乳样中的结核分枝杆菌进行检测,结果显示,在121份乳样中有3份为阳性,阳性检出率2.48%。本试验还用PCR方法对PPD检测和胶体金检测法进行验证,结果表明PCR方法敏感性强,特异性高,是一种提高牛结核病临床诊断的好方法。     

牛结核病的现状及诊断研究进展

牛结核病被世界动物卫生组织(OIE)列为B类动物疫病,是一种人兽共患传染病,其传播流行影响着畜牧业的持续发展和人类的健康。由于卡介苗(BCG)的使用,结核病的发病率比过去有所下降。但近年来由于艾滋病等其它原因,该病发病率又呈上升趋势。至今牛结核病所造成的损失大于牛的其他各种疾病所造成损失的总和。要从根本上控制牛结核病的发生与流行,必须加强对本病的研究,以便为控制和消灭牛结核病提供技术支持。文章对牛结核病的现状及诊断方法做了综述。