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1.
Subclinical mastitis caused by streptococcal infections affected 27 of 83 cows in a commercial dairy herd. Between three and six weeks after intramammary treatment of these cows with cloxacillin, 16 (59 per cent) of the treated cows developed acute clinical mastitis associated with Mycobacterium smegmatis. None of the untreated cows was affected. Infected quarters were moderately hypertrophied and fine clots were present in the milk for three to four weeks. No cows showed systemic signs of illness. Studies carried out over 12 months showed that infected cows shed M smegmatis for three to four months and affected quarters remained hypertrophied in all but one cow after 12 months. The mean milk cell count of affected quarters fell slowly from 4,850,000/ml in the acute stage to 810,000/ml five months later and 620,000/ml 12 months later, suggesting that the organism persisted in the udder. The estimated mean loss in lactation yield for cows with M smegmatis mastitis was 10.8 per cent. Losses were greatest when the hind quarters were involved (mean 28 per cent for cows with both hind quarters affected). Ten of the 16 affected cows were ultimately culled owing to serious reductions in yield.  相似文献   

2.
试验旨在构建牛分枝杆菌eis基因的穿梭表达载体,鉴定其在重组耻垢分枝杆菌中的生物学活性。采用PCR技术扩增并克隆牛分枝杆菌eis基因,构建大肠杆菌-分枝杆菌穿梭表达载体pMV261-Mbeis,经双酶切和测序鉴定其正确性,利用电穿孔法将重组质粒转化至耻垢分枝杆菌mc2155中,采用SDS-PAGE和Western blotting技术检测牛分枝杆菌eis基因在耻垢分枝杆菌中的表达,质谱鉴定目的蛋白氨基酸序列。研究结果表明,成功构建了牛分枝杆菌eis基因穿梭表达载体pMV261-Mbeis;生长曲线表明负载重组质粒不会影响耻垢分枝杆菌的体外生长;SDS-PAGE和Western blotting检测证实了牛分枝杆菌eis基因在耻垢分枝杆菌中可表达出分子质量约44 ku的eis蛋白;质谱检测证明了该蛋白即为牛分枝杆菌eis蛋白。本研究构建的牛分枝杆菌eis基因穿梭表达质粒pMV261-Mbeis在耻垢分枝杆菌中具有生物学活性,为下一步研究表达产物eis蛋白的功能奠定了基础。  相似文献   

3.
This study was aimed to construct a shuttle expression vector of Mycobacterium bovis(M.bovis) eis gene and identify its bioactivity in recombinant Mycobacterium smegmatis (M.smegmatis). M.bovis eis gene was cloned by PCR and the shuttle expression vector pMV261-Mbeis was constructed, then it was identified by double digestion and sequencing. The recombinant plasmid was transformed into M.smegmatis mc2155 by electroporation. The expression of M.bovis eis gene in M.smegmatis was detected by SDS-PAGE and Western blotting, and the amino acids sequence of the target protein was identified by mass spectrometry. The growth curve of recombinant M.smegmatis mc2155 containing pMV261-Mbeis was successfully constructed.The results showed that pMV261-Mbeis did not affect the growth of M. smegmatis in vitro. The results of SDS-PAGE and Western blotting confirmed that the M. bovis eis gene expressed the eis protein which was about 44 ku in M. smegmatis. Mass spectrometry proved that the protein was the eis protein of M. bovis.The expression vector pMV261-Mbeis was successfully constructed and the expressed recombinant protein was proved to be have biological activities in M. smegmatis, which laid a foundation for the further study of the function of eis protein in M. bovis.  相似文献   

4.
Mycobacteria were isolated and characterised from 49 cats with extensive infections of the subcutis and skin. Cats were generally between 3 and 10 years of age, and female cats were markedly over-represented. All isolates were rapid-growers and identified as either Mycobacteria smegmatis (40 strains) or M fortuitum (nine strains). On the basis of Etest for minimum inhibitory concentration and/or disc diffusion susceptibility testing, all strains of M smegmatis were susceptible to trimethoprim while all strains of M fortuitum were resistant. M smegmatis strains were typically susceptible to doxycycline, gentamicin and fluoroquinolones but not clarithromycin. All M fortuitum strains were susceptible to fluoroquinolones, and often also susceptible to gentamicin, doxycycline and clarithromycin. Generally, M smegmatis strains were more susceptible to antimicrobial agents than M fortuitum strains. Treatment of mycobacterial panniculitis involves long courses of antimicrobial agents, typically of 3-6 months, chosen on the basis of in vitro susceptibility testing and often combined with extensive surgical debridement and wound reconstruction. These therapies will result in effective cure of the disease. One or a combination of doxycycline, ciprofloxacin/enrofloxacin or clarithromycin are the drugs of choice for long-term oral therapy.  相似文献   

5.
采集猪颌下淋巴结,猪肠系膜淋巴结,牛颌下淋巴结和牛肠系膜淋巴结各200份,使用改良罗氏培养基进行分离培养和传代培养,通过进行生长特性试验、生化鉴定试验和鉴别培养基生长试验对所分离出的分枝杆菌进行菌型鉴定。结果显示:猪颌下淋巴结中分离出耻垢分枝杆菌4株,鸟分枝杆菌4株,胞内分枝杆菌2株,胃分枝杆菌2株,蟾蜍分枝杆菌1株,龟分枝杆菌龟亚种杆菌1株;猪肠系膜淋巴结未分离出非结核分枝杆菌;牛肠系膜淋巴结分离出瘰疬分枝杆菌2株,加地斯分枝杆菌1株;牛肠系膜淋巴结分离出,瘰疬分枝杆菌5株,金色分枝杆菌2株,戈登分枝杆菌2株,蟾蜍分枝杆菌2株。猪、牛的感染率均为3.5%。  相似文献   

6.
Culture filtrates derived from a Mycobacterium bovis cosmid library in Mycobacterium smegmatis were screened for T cell antigens. Recognition and reactivity were measured by the levels of lymphocyte proliferation and the levels of gamma interferon (IFN-gamma) produced when the culture filtrates were incubated with peripheral blood mononuclear cells (PBMC) taken from cattle immunised with M. bovis BCG. The screening system was optimised to distinguish between M. bovis secreted antigens and normal M. smegmatis secreted proteins. From ten culture filtrates screened, two were identified that induced lymphocyte proliferation and IFN-gamma production. Analysis of the DNA inserts from the recombinant cosmids suggest that they may code for different proteins. The results demonstrate that screening recombinant M. smegmatis culture filtrates can be used to identify M. bovis T cell antigens that are recognised by immunised cattle. These antigens may be important for the development of vaccines with protective ability against bovine tuberculosis.  相似文献   

7.
Despite the ubiquitous presence of atypical mycobacteria in the environment and the potential risk of infection in humans and animals, the pathogenesis of diseases caused by infection with atypical mycobacteria has been poorly characterized. In this study, goldfish, Carassius auratus were infected either with the rapidly growing fish pathogen, Mycobacterium fortuitum or with another rapidly growing mycobacteria, Mycobacterium smegmatis. Bacterial persistence and pathological host response to mycobacterial infection in the goldfish are described. Mycobacteria were recovered from a high percentage of inoculated fish that developed a characteristic chronic granulomatous response similar to that associated with natural mycobacterial infection. Both M. fortuitum and M. smegmatis were pathogenic to fish. Fish infected with M. smegmatis ATCC 19420 showed the highest level of giant cell recruitment compared to fish inoculated with M. smegmatis mc(2)155 and M. fortuitum. Of the three strains of mycobacteria examined, M. smegmatis ATCC 19420 was the most virulent strain to goldfish followed by M. fortuitum and M. smegmatis mc(2)155, respectively.  相似文献   

8.
An indirect ELISA was used to detect antibodies to Mycoplasma bovis in milk samples collected from a herd with M bovis mastitis. Antibodies were detected in samples from nine cows which had developed clinical M bovis mastitis. Milk from only three consistently antigen-negative cows tested positive for M bovis antibodies. These results indicate the potential value of the indirect ELISA for the detection of cows which have recently developed M bovis mastitis during the early stages of an outbreak.  相似文献   

9.
【目的】 为开发噬菌体"鸡尾酒"制剂防治奶牛乳腺炎提供生物学材料。【方法】 以实验室分离的奶牛乳腺炎源金黄色葡萄球菌82为宿主菌,通过点滴法和双层平板法在奶牛场的污水、弃奶和粪便混合物中分离并纯化其噬菌体,通过噬菌斑及透射电子显微镜对该株噬菌体的形态特征进行观察。利用核酸酶处理分析该噬菌体核酸类型,并对其裂解谱、最佳感染复数、一步生长曲线、热稳定性、pH稳定性进行研究。【结果】 分离筛选出金黄色葡萄球菌82的裂解性噬菌体P82,电镜下观察其头部为二十面体,大小约为120 nm×83 nm,有一条带可伸缩尾鞘的长尾,长约126 nm,属于有尾噬菌体目,肌尾噬菌体科。通过琼脂糖凝胶电泳鉴定其核酸类型为双链DNA （dsDNA）。噬菌体P82的最佳感染复数为0.001,对奶牛乳腺炎源金黄色葡萄球菌裂解率为36.51%（23/63）,宿主谱较广;其生长潜伏期约为25 min,爆发期约为45 min,裂解量约为74 PFU/cell;在pH 4.0~12.0时活性稳定,在pH 2.0和13.0时则完全失去活性。噬菌体P82热稳定性较高,在70 ℃作用60 min后仍有裂解能力,在80 ℃作用40 min时则失去裂解能力。【结论】 本研究分离的噬菌体P82效价较高、裂解能力强、增殖速度快、噬菌谱广,对不同温度和pH均有较好的耐受度,能作为专一性裂解奶牛乳腺炎源金黄色葡萄球菌的噬菌体候选株,可与其他噬菌体混合制成噬菌体"鸡尾酒"制剂用于防治奶牛乳腺炎,为奶牛乳腺炎的噬菌体疗法提供材料。  相似文献   

10.
Sera from experimentally infected rabbits were used to test the specificity of the fluorescent antibody test. It was possible using mono-specific sera to differentiate antigenically Mycobacterium phlei, M fortuitum, M smegmatis, M avium, M intracellulare, M bovis (BCG) and M johnei. The cross-reactivity within the M avium and M intracellulare group was such that one antigen from these groups would detect infection within that group and exclude M johnei infection. The M phlei growth factor independent strain M johnei 316F was shown to be antigenically distinct from a M phlei dependent strain 9N96. There was loss of specificity when M avium infection was superimposed on a previous M johnei infection and when M johnei infection was superimposed on M avium infection.  相似文献   

11.
Pyogranulomatous panniculitis due to infection by Mycobacterium smegmatis was diagnosed in two cats in Finland, a country with a rather cold climate. The diagnosis was confirmed by sequencing of the 16S rRNA gene, which gave a perfect match with the M smegmatis strain ATCC 19420. Gene sequencing makes it possible to distinguish M smegmatis from closely related mycobacteria such as M goodii sp.nov. Diagnosing this entity seems to be a question of having a high index of suspicion. The appearance of the disease as well as sampling is described in detail. In our first case an initial erroneous diagnosis of Nocardia species considerably delayed our arriving at the right diagnosis. The first patient has now been followed for more than 7 years. Her disease is chronic, but she is not systemically affected. Several antimicrobials were tried. Probable side effects of enrofloxacin medication are described.  相似文献   

12.
The objective was to determine the incidence and transmission of mycoplasma mastitis in the hospital pen in a dairy herd of 650 lactating cows after a hospital pen was established following an outbreak of this disease. Mycoplasma mastitis status was monitored for 3 months through repeated collection of milk samples from cows with clinical mastitis (CM) and from bulk tank milk. During the outbreak 13 cows were diagnosed with Mycoplasma bovis CM, 1 cow with Mycoplasma sp. mastitis and 8 cows showed signs of arthritis, 3 of which were confirmed as having M. bovis arthritis. M. bovis isolates from cows with CM, arthritis and bulk tank milk had indistinguishable chromosomal digest pattern fingerprints. Incidence rates of M. bovis CM cases in the milking and hospital pens were 0.01 and 1.7 cases per 100 cow-days at risk. Approximately 70% of cows with M. bovis CM became infected within 12 days of entering the hospital pen. Transmission of M. bovis in the hospital pen occurred as 3 episodes. Each episode corresponded to the introduction of a cow with M. bovis CM from a milking pen. Evidence indicates that cows with M. bovis CM from milking pens were the source of transmission of the disease in the hospital pen and thus their presence in the hospital pen appeared to be a risk factor for transmission of M. bovis mastitis in this single case study herd.  相似文献   

13.
We describe three different outbreaks of mastitis caused by M. mycoides subspecies mycoides LC type (Mmm LC) in three goat flocks from the Extremadura Region of south-west Spain. Thirty-two fast-growing isolates were obtained on Hayflick's and Friis's media with inhibitors from different specimens. All were identified as Mmm LC in spite of their cultural, biochemical and serological features.  相似文献   

14.
A highly sensitive and specific PCR (MB-PCR) was used in preliminary studies to detect M. bovis in milk samples to investigate its association with high somatic cell count (SCC), an indicator of subclinical mastitis and one of the factors in down grading the quality of milk. A total of 186 and 167 herds were tested with 43% and 62% of herds positive for M. bovis in Victoria and North Queensland, respectively. The quarter milks from 52 cows with persistently high SCC were tested by MB-PCR and culture to investigate the association of M. bovis with major mastitis pathogens (MMP). M. Bovis was detected in 77% of cows of which 19% alone had M. bovis without any other bacteria, 17% had M. bovis in combination with major mastitis pathogens and 40% had M. bovis in combination with non-major mastitis pathogens. We believe that M. bovis is widespread in dairy cattle and has the potential to produce disease alone or to predispose the udder to disease caused by major mastitis and environmental pathogens. These studies have revealed a hitherto unrecognised high prevalence of M. bovis in dairy cattle in North Queensland and Victoria in Australia. These initial studies also give a clear association between M. bovis and elevated somatic cell counts.  相似文献   

15.
从奶牛分离得到耐甲氧西林金黄色葡萄球菌（methieillin—resistant Staphylococcus aureus,MRSA）。按常规方法复苏菌株,用血浆凝固酶试验鉴定SA。用KB法、琼脂筛选法、生化鉴定法（VITEK32）、聚合酶链反应等鉴定MRSA。常规分离鏊定的葡萄球菌468株,其中凝固酶阴性葡萄球菌（coagulase negative Staphylococcus,CNS）361株,检出率为77．149,6,金黄色葡萄球菌（Staphylococcus aureus,SA）105株,检出率为22．44％,MRSA36株检出率为34．29％,2株未定型,占0．42％。而MRSA在乳房炎奶样中检出率高达34．29％,表明新疆兵团部分垦区牛场MRSA已经呈蔓延趋势。  相似文献   

16.
This study is the first investigation on Japanese isolates of Prototheca zopfii from bovine mastitis and the cow-barn surroundings by molecular characterization to clarify routes of infection for bovine protothecal mastitis. We performed isolation of Prototheca from cow-barn surroundings (drinking water, sewage and feces) and milk samples from cases of bovine mastitis. Genotypes of the 32 isolates of P. zopfii from cow-barn surroundings and 67 isolates from mastitis were analyzed by genotype-specific PCR assays and restriction fragment length polymorphism (RFLP) assays. All mastitis isolates were identified as P. zopfii genotype 2. Conversely, 29 isolates from cow-barn surroundings were identified as P. zopfii genotypes 1 and 3 isolates as genotype 2, respectively. Given these results, both genotypes of P. zopfii could exist in cow-barn surroundings, but no sites were identified as frequent sources of P. zopfii genotype 2. P. zopfii isolates should thus be further explored with regard to genotype to clarify the reservoir of etiological agents in bovine Prototheca mastitis.  相似文献   

17.
ABSTRACT: Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland.  相似文献   

18.
Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.  相似文献   

19.
Bovine mastitis is mainly caused by Staphylococcus aureus and antimicrobial therapy, commonly used for its control, has resulted in an increase in the frequency of resistant staphylococci in recent years. Thus, alternative therapies are desirable and the antimicrobial peptides represent attractive control agents. In this work, we expressed the antimicrobial peptide thionin Thi2.1 cDNA from Arabidopsis thaliana in the bovine endothelial cell line BVE-E6E7 and evaluated its activity against bovine mastitis S. aureus isolates. A polyclonal population from BVE-E6E7 cells transfected with the pThi2.1 construct was obtained and thionin Thi2.1 expression was confirmed by RT-PCR. From this population, eight stably transfected cell clones were obtained and their conditioned media (CM) were evaluated against the S. aureus ATCC 27543 strain. Clones showed high antibacterial activity (>95%) relative to the activity of the polyclonal population. The C8 clone showed the highest antibacterial activity (>99%) and its CM was evaluated against eleven bovine mastitis S. aureus isolates. A 2.5microg aliquot of total protein from the C8 clone's CM inhibited the growth of S. aureus isolates (>40%) relative to the CM from BVE-E6E7 cells used as control. Growth inhibition of S. aureus isolates was dose-dependent, showing a total inhibition at concentrations higher than 3.12microg/ml. These results suggest that thionin Thi2.1 antimicrobial peptide could be use in the treatment of bovine mastitis.  相似文献   

20.
Strains of M. bovis, A. laidlawii, A. axanthum, and one unidentified strain of the family of mycoplasmataceae as well as altered secretion obtained from cows with mastitis were intracisternally applied in experiments and proved to be pathogenic to cattle udder. The results are likely to suggest the importance of mycoplasma isolated from the milk of mastitis cows to the aetiology of enzootic mastitis in three large dairy cattle stocks. Intravenous application of M. bovis and A. laidlawii caused neither mastitis nor mycoplasma secretion in the milk.  相似文献   

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