用MLVA技术和多重PCR对犬种布氏菌基因分型

目的：对犬种布氏菌的遗传关系进行不同分子分型方法的对比研究,为犬布病分子流行病溯源提供有效方法。方法：采用多重PCR和多位点可变数量串联重复序列分析（MLVA）方法对24株犬种布氏菌的遗传关系进行比较研究。结果：多重PCR只鉴定出1株犬种布氏菌,其余23株均鉴定为猪种鲁氏菌,但不能鉴定型别;MLVA方法对已鉴定为猪种的布氏菌仍可再细分为型,87%（20/23）为猪3型,13%（3/20）为猪1型。结论：MLVA可以对布氏菌种（生物型）进行基因分型鉴定,可以作为传统表型鉴定方法的补充。     

Investigation of arcobacters in meat and faecal samples of clinically healthy cattle in Turkey

AIMS: To investigate the presence of Arcobacter spp. in minced beef meat (n = 97) and rectal faecal samples (n = 200) collected from cattle immediately after slaughter at a local abattoir in Turkey. METHODS AND RESULTS: Meat samples were examined using three different isolation procedures (CAT-supplemented media, de Boer arcobacter isolation method and membrane filtration method), but only one method (CAT-supplemented media) was employed for faecal samples. The isolated Arcobacter strains were identified by genus- and species-(multiplex) specific PCR assays. Arcobacter spp. were isolated from 5 and 9.5% of meat and faecal samples respectively. Although the only Arcobacter sp. found in meat samples was Arcobacter butzleri, all three pathogenic species--A. butzleri, A. cryaerophilus and A. skirrowii--were detected in the rectal swabs. No Arcobacter was isolated when the de Boer method was used for minced meat samples but the same five meat samples were found positive for arcobacters when CAT-supplemented media and membrane filtration method were used. CONCLUSIONS: The membrane filtration method was found to be superior to the CAT-supplemented media, because it led to a reduction in competing microflora. However, the necessity for one filter and medium for each sample makes this method somewhat expensive. The multiplex-PCR (m-PCR) assay shortened significantly the time required for the identification of Arcobacter spp. and also removed the possibility of false positive results due to other campylobacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reports the isolation of Arcobacter spp. in cattle for the first time in Turkey. The m-PCR assay enables the identification and differentiation of all arcobacters simultaneously in one-step PCR.     

Shiga toxin-producing Escherichia coli and enteropathogenic Escherichia coli in healthy goats in India: occurrence and virulence properties

AIMS: To describe the occurrence and virulence gene pattern of shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) in healthy goats of Jammu and Kashmir, India. METHODS AND RESULTS: A total of 220 E. coli strains belonging to 60 different 'O' serogroups was isolated from 206 local (nonmigratory) and 69 migratory goats. All the 220 strains were screened for the presence of stx(1), stx(2), eaeA and hlyA genes. Twenty-eight E. coli (75.6%) strains from local and nine (24.3%) strains from migratory goats belonging to 18 different serogroups showed at least presence of one virulence gene studied. Twenty-eight strains (16.47%) (belonging to 13 different serogroups) from local goats carried stx(1) gene alone or in combination with stx(2) gene, while as only one strain (2%) from migratory goats possessed stx(2) gene alone. Interestingly in the present study none of the STEC strains carried eaeA gene. Similarly, none of the strains from local goats possessed eaeA and none of the migratory goats possessed stx(1) gene. Eight strains (16%) (belonging to four different serogroups) from migratory goats carried eaeA gene. Twenty-five (14.7%) and seven (14%) strains from local and migratory goats harboured hlyA gene respectively. CONCLUSIONS: Healthy goats of Jammu and Kashmir state serve as a reservoir of STEC and EPEC. Further studies in this direction are needed to work out whether or not they are transmitted to humans in this part of world. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report of isolation of STEC and EPEC strains from healthy goats in Jammu and Kashmir State of India, which could be a source of infection to humans.     

Development of a multiplex-PCR for rapid detection of the enteric pathogens Lawsonia intracellularis, Brachyspira hyodysenteriae, and Brachyspira pilosicoli in porcine faeces

AIMS: To develop an assay to simultaneously detect Lawsonia intracellularis, Brachyspira hyodysenteriae and Brachyspira pilosicoli in pig faeces. METHODS AND RESULTS: A multiplex-polymerase chain reaction (M-PCR) was designed to amplify a 655-base pair (bp) portion of the L. intracellularis 16S rRNA gene, a 354-bp portion of the B. hyodysenteriae NADH oxidase gene, and a 823-bp portion of the B. pilosicoli 16S rRNA gene. Specificity was assessed using 80 strains of Brachyspira spp. and 30 other enteric bacteria. Bacterial DNA was extracted from faeces using the QIAamp DNA Stool Mini Kit. The M-PCR was tested in parallel with culture and/or PCR on 192 faecal samples from eight piggeries. Faeces also were seeded with known cell concentrations of the three pathogenic species, and the limits of detection of the M-PCR tested. The M-PCR was specific, with limits of detection of 10(2)-10(3) cells of the respective species per gram of faeces. CONCLUSIONS: The M-PCR is a rapid, sensitive and specific test for detecting three important enteric bacterial pathogens of pigs. SIGNIFICANCE AND IMPACT OF THE STUDY: The availability of a new diagnostic M-PCR will allow rapid detection and control of three key porcine enteric pathogens.     

Retrospective study of a plague outbreak by multiplex-PCR

AIMS: To determine the effectiveness of multiplex-PCR in Yersinia pestis identification in samples preserved in Cary & Blair medium and to evaluate if this technique would uncover Y. pestis-positives among culture-negative samples. METHODS AND RESULTS: Multiplex-PCR was used to detect Y. pestis in Cary & Blair preserved bubo aspirates from experimentally infected guinea pigs and to re-analyze samples from a plague outbreak after prolonged storage in Cary & Blair. Variation in the target genes amplification was observed over time. CONCLUSIONS: Multiplex-PCR proved to be more effective than culture for plague diagnosis, both for old and recent samples. This technique would be a valuable tool for the plague control programme. SIGNIFICANCE AND IMPACT OF THE STUDY: The multiplex-PCR technique can be useful for the detection and characterization of Y. pestis even when the bacteria are no longer viable and when culture diagnosis has been hampered by the growth of contaminants.     

应用多重PCR鉴定微生物肥料常用芽孢杆菌

[目的]枯草群芽孢杆菌中枯草芽孢杆菌(Bacillus subtilis)、解淀粉芽孢杆菌(B.amyloliq-wefaciens)、地衣芽孢杆菌(B.licheniformis)和短小芽孢杆菌(B.pumilus)是微生物肥料中常用菌种,用传统方法鉴定费时费力,有必要建立检测和鉴定这些芽孢杆菌的种特异性PCR方法.[方法]利用已登录的gyrA、rpoA和16s rRNA基因序列分别设计和筛选上述菌种的特异引物并建立多重PCR反应体系.[结果]以基因组DNA为模板,扩增芽孢杆菌、类芽孢杆菌和短芽孢杆菌3属15种的标准菌株(共33株),4个目标种分别产生了大小不同的唯一的产物,除个别种与短小芽孢杆菌引物有交叉反应外,其余参考菌株均为阴性.从23株枯草群菌株的基因组DNA扩增发现,PCR鉴定与常规鉴定结果一致.[结论]本文建立的多重PCR方法具有较好的特异性,可快速准确鉴定枯草群的4个种,在微生物肥料检测方面有良好的实用前景.     

A convenient and efficient microsatellite-based assay for resolving parentages in dogs

We present a practical and efficient parentage analysis test for dogs. The method makes use of ten polymorphic microsatellite markers combined in three multiplex-PCR reactions. All three multiplexes can be performed under the same cycling conditions and using a multiple-dye detection system the PCR-products can be pooled for electrophoresis. Amplifications in four different thermal cyclers produced easily interpretable results throughout demonstrating the repeatability of the assay. In order to evaluate the method's efficiency a total of 100 dogs from four different breeds were typed. Assuming one known parent, exclusion probabilities ranging from 99.34% to 99.93% were attained.     

Strain-specific detection of two Aureobasidium pullulans strains, fungal biocontrol agents of fire blight by new, developed multiplex-PCR

Aim:  The aim of this study was to develop a specific and sensitive identification method for two Aureobasidium pullulans biocontrol strains, CF10 and CF40, based on a sequence-characterized amplified region (SCAR) derived from RAPD – and multiplex-RAPD PCR analysis. Methods and Results:  The random amplified polymorphic DNA (RAPD) and multiplex RAPD-PCR techniques were used for a preliminary screening of A. pullulans genetic variability among 200 isolates. This approach allowed the selection of ten fragments present solely in strains CF10 and CF40. The RAPD fragments were cloned, sequenced and used to design two SCAR primers. Two primer pairs obtained from SCH3RAPD fragment of CF 40 and 6RAPD of CF10 were highly specific and sensitive. Conclusions:  In this study, we developed strain-specific multiplex-PCR based on sequence-characterized amplified region (SCAR) markers to simultaneously detect both strains in a single PCR. Significance and Impact of the Study:  This new multiplex-PCR provides a valuable tool for specific and sensitive identification of CF10 and CF40, and could be used in studies on the efficacy and persistence of introduced strains of A. pullulans for fire blight control.     

First Evaluation of an Outbreak of Bovine Babesiosis and Anaplasmosis in Southern Brazil Using Multiplex PCR

Outbreaks of tick-borne disease cases in Santa Catarina, Brazil are known, but the presence of the pathogen DNA has never been determined. In this study, the first survey of Anaplasma marginale, Babesia bigemina, and Babesia bovis DNA on blood samples of 33 cattle from an outbreak in Ponte Alta Municipality, Santa Catarina, Brazil, has been carried out. A multiplex PCR detected 54.5% of animals were co-infected with 2 or 3 parasites, while 24.2% were infected with only 1 species. The most prevalent agent was B. bigemina (63.6%) followed by A. marginale (60.6%). This is the first report of tick-borne disease pathogens obtained by DNA analysis in Southern Brazil.     

一种检测转1Dx5基因小麦植株的新方法

目的:建立一种有效区分Glu-1D等位基因的Multiplex-PCR体系,快速检测转1Dx5小麦植株。方法:根据1Dx5和1Dx2亚基基因的区别设计特异的PCR引物,通过多重PCR技术检测花粉管通道法转化1Dx5核心片段的转基因T1代植株。结果:Multiplex-PCR能够在转基因T1代材料中扩增Glu-1D等位基因的特征条带,分别为343bp、320bp的1Dx5基因特异片段以及361bp的1Dx2基因特异片段,与预期结果一致。结论:该技术能够检测多个靶基因,有效地区分转基因Glu-1D上的等位基因,证实外源1Dx5基因已整合到受体基因组中,对检测基因组庞大、外源基因序列GC含量高且与内源基因同源性高的转基因小麦十分有效。