DNA数目可变串联重复序列用于结核分枝杆菌分型研究

目的　采用数目可变串联重复序列(VNTR)分型方法对安徽省的52株结核分枝杆菌进行分子分型研究,探讨该方法用于结核分枝杆菌分型的作用。方法 设计引物,采用PCR和琼脂糖凝胶电泳技术对结核分枝杆菌13个VNTR位点进行检测,并通过BioNumerics30软件进行DNA指纹图谱多态性分析。结果 52株结核分枝杆菌可分4个类别,其中88.5%菌株属于一个型,其他3个型所占比例很小,分别为5.8%、3.8%和1.9%。结论 来自安徽的结核分枝杆菌存在主要的流行型,VNTR分型技术简便、快速,是较好的结核分枝杆菌分型方法。     

新疆某牛场牛结核病的综合诊断与病原分离鉴定

目的 用多种方法检测新疆某牛场的结核病并分离病原。方法 选择皮内变态反应、牛型PPD点眼试验、IFN-γ试验及ELISA抗体检测试验4种免疫学诊断方法对新疆某牛场进行牛结核病的综合诊断,锁定疑似阳性牛后进行扑杀、剖检并采集病料进行病原的分离,用已建立的PCR方法对培养的细菌进行分型鉴定。结果 共检测了奶牛755头,其中4种方法综合锁定结核疑似阳性牛26头(3.4%)。从中随机选择5头牛进行剖检均发现有明显的结核病变,采样后在罗氏培养基上进行培养,结果均为阳性。挑取菌落经PCR鉴定结果均为牛分枝杆菌。结论 牛结核病的诊断存在其他分枝杆菌的干扰,单一诊断方法因特异性不足导致结果存在误差。合理选择诊断方法的组合有利于牛结核病的确诊。     

我国结核与非结核分枝杆菌混合感染的系统性回顾及Meta分析

目的 了解我国结核(TB)与非结核分枝杆菌(NTM)混合感染的流行现状以及对结核病防控的影响。方法 检索中外文文献数据库,纳入2020年以前发表的包含大陆地区结核病患者临床样本中分枝杆菌分离鉴定数据的原始文献,系统性回顾分析TB/NTM的混合感染情况。结果 在疑似/确诊结核病患者中,分枝杆菌的粗分离率为35.4%(28.9%~41.9%),NTM的粗分离率为5.2%(4.7%~5.7%),NTM在分枝杆菌中的占比为12%(11.2%~12.7%);NTM/TB混合感染在疑似/确诊结核病人中的分离率为0.6%(0.2%~1.1%),在分枝杆菌中的占比为1.4%(1.1%~1.8%)。结论 国内对NTM/TB混合感染的报道非常有限,检测方法和成本阻碍了混合感染的检出。     

114例HIV/MTB双重感染病例结核分枝杆菌Spoligotyping基因分型研究

目的 了解HIV/MTB双重感染病例中结核分枝杆菌基因型构成情况以及北京家族基因型菌株所占的比例,为HIV/MTB双重感染病例结核病预防控制提供分子流行病学依据。方法 收集HIV/MTB双重感染病例结核分枝杆菌临床分离株114株,利用间隔寡核苷酸分型(Spoligotyping)技术对所收集的临床分离株进行分型研究,分析HIV/MTB双重感染病例中结核分枝杆菌基因型构成情况及主要流行型。结果 114例HIV/MTB双重感染病例结核分枝杆菌成2个大的基因家族,即北京家族(Beijing Family)和非北京家族(non-Beijing Family),分别占66.7%(76/114)和33.3%(38/114),共30种基因型。其中,非北京家族包括T家族共18株,H家族共5株,EAI5基因家族1株,CAS1_DEHLI基因家族1株及12种在数据库中没有对应基因家族或没有匹配的结果的新基因型13株。结论 HIV/MTB双重感染病例中,结核分枝杆菌基因型呈明显的多态性,北京家族基因型菌株仍为HIV/MTB双重感染病例中结核分枝杆菌主要流行菌株。     

rDNA探针杂交检测病人痰标本中结核杆菌的研究

目的 应用结核分枝杆菌特异的rDNA探针杂交检测痰标本中的结核杆菌rDNA,评价其在临床标本检测中的应用价值。方法 用引物b对结核分枝杆菌16S-23SrDNA间隔区序列进行扩增,同时加入生物素标记,制成250bp的rDNA探针。对该探针的敏感性、特异性进行了研究,并对90份结核病人,30份非结核病人痰标本的PCR产物进行了斑点杂交检测。结果 rDNA探针检测引物bPCR扩增产物的敏感性为100pg。rDNA探针与受试24种分枝杆菌和11种非分枝杆菌引物bPCR扩增产物杂交只有结核分枝杆菌、胃分枝杆菌为阳性杂交,特异性较高。而rDNA探针对90份结核病人痰标本引物b扩增产物检测的阳性率为80.2%,高于PCR扩增产物电泳检测结果 (64%)。rDNA探针与30份非结核病人痰标本杂交结果均为阴性杂交。结论 rDNA探针与引物bPCR扩增相结合能提高结核病人痰标本检测的敏感性与特异性。     

某高级中学结核病爆发分离菌株的实验室鉴定

目的鉴定从某中学结核病爆发分离菌株的种属。方法对2006年5—8月,辽宁省某高级中学发生的10例痰检阳性病例中的3份痰标本分离的菌株经表型鉴定方法;传统生化方法;扩增hupB基因、dnaA-dnaN 和NTF-1区;Spoligotyping 以及MIRU基因分型;16S rRNA基因、16S-23S ITS和hsp65基因测序以及hsp65基因限制性酶切分析进行鉴定。结果临床分离株经生化方法初步鉴定1份为结核分枝杆菌复合群和2份为非结核分枝杆菌,随后经表型鉴定和扩增hupB基因、dnaA-dnaN 和NTF-1区;Spoligotyping 以及MIRU基因分型,说明属于结核分枝杆菌复合群的菌株为结核分枝杆菌北京基因型现代株,MIRU基因型为223325173533。经16S rRNA基因、16S-23S ITS和hsp65基因测序以及hsp65基因限制性酶切分析说明属于非结核分枝杆菌的菌株为猪分枝杆菌。结论本次从结核病爆发累及病人的标本中分离出结核分枝杆菌北京基因型现代株和猪分枝杆菌,猪分枝杆菌在暴发流行中的意义尚需进一步研究。     

结核病诊断性血清学特异抗原的筛选和鉴定

目的 筛选和鉴定结核病患者血清抗体特异性识别的结核分枝杆菌抗原。方法 于改良罗氏培养基中培养结核分枝杆菌标准株H37Rv 4周,收集菌体,通过冰浴超声法提取结核分枝杆菌菌体抗原。收集2013年2—7月湖南省结核病防治所首次入院的30例初治结核病患者的血清,以及收集2013年7月湖南省人民医院检验科接收的20名健康体检者的血清。通过饱和硫酸铵沉淀法提取纳入的20例结核病患者的血清IgG,从结核分枝杆菌菌体抗原中免疫共沉淀血清学抗原,以纳入的其余10例结核病患者血清免疫印迹(Western blot,WB)验证其免疫反应性;从十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)胶上切割阳性反应的蛋白质条带,通过串联质谱技术进行鉴定。结果 免疫共沉淀获得1条相对分子质量为16000(16kDa)、能被结核病患者血清抗体特异性识别的蛋白质条带;经串联质谱鉴定,获得结核分枝杆菌热休克蛋白(heat shock protein,Hsp)16.3、糖基转移酶蛋白、铁调控Lsr2蛋白前体等3种蛋白抗原。结论 采用免疫共沉淀偶联质谱技术获得3种结核分枝杆菌血清学抗原,可为结核病血清学诊断性抗原的选择进一步提供依据。     

RT-LAMP与LAMP法检测结核分枝杆菌的效果比较

目的 比较RT-LAMP、LAMP、L-J法检测MTB的效果,为结核病的快速诊断提供依据。方法 用常见的非结核分枝杆菌与其他常见的呼吸道感染病菌(金黄色葡萄球菌、铜绿假单胞菌、肺炎克雷伯杆菌)检测特异性,并用酶切实验对结核分枝杆菌特异性产物进行酶切鉴定;用RT-LAMP、LAMP、L-J法检测100名结核病患者和22名来自无结核病患者痰标本中的结核分枝杆菌测试灵敏性;对浓度为1 ng/μL H37Rv标准株进行对倍比稀释用于RT-LAMP极限检测实验。结果 RT-LAMP、LAMP、L-J方法的阳性率分别为100%,92%和88%;RT-LAMP和L-J, RT-LAMP和LAMP差异均有统计学意义;RT-LAMP的灵敏度比LAMP高10倍;RT-LAMP不仅可以识别活菌,并且能够重复检测MTB的单一拷贝。结论 RT-LAMP检测效果优于LAMP及L-J,适于基层医院结核病诊断的推广和应用。     

23株非结核分枝杆菌药物敏感性试验分析

目的 对自贡市临床分离鉴定的23株非结核分枝杆菌分别进行26种抗生素的药物敏感试验,了解非结核分枝杆菌对不同抗生素的耐药性,为非结核分枝杆菌病临床治疗提供依据。方法 采用微孔板阿尔玛蓝测定法(microplate Alamarblue assay,MABA)测试每种药物对每株非结核分枝杆菌的最低抑菌浓度(MIC值),通过MIC值判断该菌对此种抗生素是否耐药。结果 非结核分枝杆菌对大部分抗结核药物耐药,并且对部分药物的耐药存在种间差异。其中脓肿分枝杆菌耐药率达84.6%,鸟分枝杆菌与胞内分枝杆菌分别达53.8%与52.3%,堪萨斯分枝杆菌耐药率最低为38%。结论 对临床非结核分枝杆菌肺病,快速菌株鉴定及药敏试验是治疗的关键。     

复方PCR用于分支杆菌菌种鉴定的初步研究

目的　寻找新的、快捷简便的分支杆菌菌种鉴定技术,进一步提高临床结核病诊断的水平。方法 将3套分支杆菌基因组DNA的不同标记引物同时放入一个体系中,并在同一退火温度下进行PCR扩增,通过对扩增产物的不同带型进行分析,对已知标准株和部分临床株进行菌种鉴定。结果 复方PCR方法可将结核复合群中的结核分支杆菌、牛结核分支杆菌与非结核分支杆菌一次性地区分开,特异性达到100%,灵敏度为10ng/反应。结论 复方PCR技术是一种有效而又简捷的分支杆菌诊断方法,可用于临床上分结核与非结核分支杆菌或分支杆菌与非分支杆菌的初步区分。     

Polymerase chain reaction detection of Mycobacterium paratuberculosis and Mycobacterium avium subsp silvaticum in long term cultures from Crohn''s disease and control tissues.

Thirty one cultures were established in MG3 medium from the intestinal tissues of 29 patients, including 18 with Crohn's disease, five with ulcerative colitis, and six non-inflammatory bowel disease controls. All cultures grew either acid fast bacilli or uncharacterized spheroplasts. Pellets from these cultures were coded and assayed blind for M paratuberculosis and M avium subsp silvaticum using IS900- and IS902-PCR (polymerase chain reaction) assays, respectively. IS900 and IS902 are multicopy DNA insertion elements specific for these two organisms. Six Crohn's disease cultures and a single non-inflammatory bowel disease control were positive for M paratuberculosis. A further six cultures were positive for M avium subsp silvaticum, of which two each were from Crohn's disease, ulcerative colitis, and non-inflammatory bowel disease controls. The intensity of the IS900-PCR signals indicated very low numbers of M paratuberculosis organisms and bore no relation to visible spheroplastic or bacillary mycobacterial growth. The results suggest that M paratuberculosis isolated from man exists in a form which hardly replicates if at all when cultured in MG3 medium in vitro, and are consistent with the involvement of this known animal enteric pathogen in a proportion of chronic enteritis in man.     

Specific detection of Mycobacterium paratuberculosis by DNA hybridisation with a fragment of the insertion element IS900.

This paper describes the evaluation of a newly developed DNA probe for Mycobacterium paratuberculosis. DNA probe PCR278 is a 278 bp fragment obtained by polymerase chain reaction (PCR) amplification of the 5'-region of IS900, an insertion element contained in the genome of M paratuberculosis. This DNA probe can specifically distinguish M paratuberculosis from a wide range of other organisms, including members of the M avium-M intracellulare complex. When used in conjunction with the PCR amplification technique DNA probe PCR278 could detect as little as 10 fg (equivalent to two genomes) starting material of M paratuberculosis genomic DNA. Use of PCR amplification assays based on IS900, for the detection of M paratuberculosis, and homologous IS elements found in disease isolates of M avium should greatly help our understanding of the role of these organisms in Crohn's disease and other chronic inflammatory disorders.     

Genotype profiles of Mycobacterium avium subspecies paratuberculosis recovered from suspected and Crohn's disease patients in India

Present study aimed to genotype Mycobacterium avium subspecies paratuberculosis (MAP) recovered from suspected and Crohn' s disease patients. A total of 32 MAP and DNA (directly from clinical samples) recovered from human origin were genotyped using IS 1311 PCR-REA. Isolates were cultured from stool, biopsies and blood clots of Crohn's disease patients, and stool samples of suspected (animal attendants, lab workers etc). Of the 32 MAP isolates belonging to 28 human beings, majority (84.3%) were genotyped as 'Bison type', while 21.7% were of 'cattle' and none was 'sheep' genotype. Study first time reports distribution of 'Cattle' and 'Bison type' 'genotypes in suspected and Crohn's patients on pilot scale in India. 'Bison type' genotype was predominant in the surveyed human population.     

Molecular evidence for Mycobacterium avium subspecies paratuberculosis (MAP) in Crohn''s disease correlates with enhanced TNF-α secretion

BACKGROUND: Support for a role of Mycobacterium avium subspecies paratuberculosis in Crohn's disease is largely based on epidemiological evidence, as no data on mechanisms linking the presence of M. avium subspecies paratuberculosis with gut damage is available. AIMS: To determine whether the presence of M. avium subspecies paratuberculosis contributes to the pathogenesis of Crohn's disease by promoting cytokine secretion within gut mucosa. PATIENTS AND METHODS: A total of 235 subjects were recruited: 63 with Crohn's disease, 53 with ulcerative colitis, 45 with irritable bowel syndrome and 74 normal controls. M. avium subspecies paratuberculosis status was defined by nested PCR using IS900 sequence. Gut mucosal organ cultures were established to detect cytokine secretion patterns. RESULTS: Significantly higher tumour necrosis factor-alpha concentrations were found in culture supernatants for Crohn's disease compared to ulcerative colitis (p<0.05), irritable bowel syndrome (p<0.01) and controls (p<0.0001). When tumour necrosis factor-alpha levels were correlated with the presence of M. avium subspecies paratuberculosis, significantly greater concentrations were only found in M. avium subspecies paratuberculosis-positive Crohn's disease patients (p<0.05). Tumour necrosis factor-alpha levels in M. avium subspecies paratuberculosis-positive Crohn's disease were significantly higher than in M. avium subspecies paratuberculosis-positive ulcerative colitis (p<0.01), M. avium subspecies paratuberculosis-positive irritable bowel syndrome (p<0.05) and M. avium subspecies paratuberculosis-positive controls (p<0.01) and all M. avium subspecies paratuberculosis-negative specimens. CONCLUSIONS: The data link M. avium subspecies paratuberculosis with a pathogenic mechanism in Crohn's disease and is consistent with abnormal macrophage handling of M. avium subspecies paratuberculosis.     

Mycobacterium paratuberculosis DNA in Crohn''s disease tissue.

Crohn's disease has long been suspected of having a mycobacterial cause. Mycobacterium paratuberculosis is a known cause of chronic enteritis in animals, including primates, but may be very difficult to detect by culture. IS900 is a multicopy genomic DNA insertion element highly specific for M paratuberculosis. A polymerase chain reaction (PCR) based on the 5' region of IS900 and capable of the specific detection of a single M paratuberculosis genome was developed. This was applied to DNA extracts of full thickness samples of intestine removed at surgery from 40 patients with Crohn's disease, 23 patients with ulcerative colitis, and 40 control patients without inflammatory bowel disease. Stringent precautions were taken that excluded contamination artefact. M paratuberculosis was identified in 26 of 40 (65%) Crohn's disease, in 1 of 23 (4.3%) ulcerative colitis, and in 5 of 40 (12.5%) control tissues. Positive samples from Crohn's disease were from both the small intestine and colon, those from control tissues were from the colon those from control tissues were from the colon only. All PCR internal control reactions were negative. The presence of M paratuberculosis in a small proportion of apparently normal colonic samples is consistent with a previously unsuspected alimentary prevalence in humans. The presence in two thirds of Crohn's disease tissues but in less than 5% of ulcerative colitis tissues is consistent with an aetiological role for M paratuberculosis in Crohn's disease.     

Detection and Isolation of Mycobacterium avium subspecies paratuberculosis from intestinal mucosal biopsies of patients with and without Crohn's disease in Sardinia

OBJECTIVES: Sardinia is an island community of 1.6 million people. There are also about 3.5 million sheep and one hundred thousand cattle in which Johne's disease and Mycobacterium avium subspecies paratuberculosis infection are endemic. The present study was designed to determine what proportion of people in Sardinia attending for ileocolonoscopy with or without Crohn's disease were infected with this pathogen. METHODS: Mycobacterium avium subspecies paratuberculosis was detected by IS900 PCR on DNA extracts of fresh intestinal mucosal biopsies as well as by isolation in culture using supplemented MGIT media followed by PCR with amplicon sequencing. RESULTS: Twenty five patients (83.3%) with Crohn's disease and 3 control patients (10.3%) were IS900 PCR positive (p = 0.000001; Odds ratio 43.3). Mycobacterium avium subspecies paratuberculosis grew in cultures from 19 Crohn's patients (63.3%) and from 3 control patients (10.3%) (p = 0.00001; Odds ratio 14.9). All patients positive by culture had previously been positive by PCR. Mycobacterium avium subspecies paratuberculosis first appeared in the liquid cultures in a Ziehl Neelsen (ZN) staining negative form and partially reverted through a rhodamine-auramine positive staining form to the classical ZN positive form. This resulted in a stable mixed culture of all 3 forms illustrating the phenotypic versatility of these complex chronic enteric pathogens. CONCLUSIONS: Mycobacterium avium subspecies paratuberculosis was detected in the majority of Sardinian Crohn's disease patients. The finding of the organism colonizing a proportion of people without Crohn's disease is consistent with what occurs in other conditions caused by a primary bacterial pathogen in susceptible hosts.     

High prevalence of Mycobacterium avium subspecies paratuberculosis IS900 DNA in gut tissues from individuals with Crohn's disease

BACKGROUND AND AIMS: Conflicting results exist about the presence of Mycobacterium avium subspecies paratuberculosis (MAP) specific IS900 DNA in Crohn's disease (CD) tissues. Therefore, we examined IS900 in a large number of gut samples from patients with CD (n = 100) and ulcerative colitis (UC, n = 100), and in non-inflamed control tissues (nIBD, n = 100). We hypothesised that IS900 DNA detection might be associated with distinct clinical phenotypic characteristics in CD. METHODS: The prevalence of MAP DNA in surgically resected tissues was examined using a mechanical-enzymatic disruption technique and nested IS900 specific polymerase chain reaction (PCR). CD patients were stratified according to the criteria of the Vienna classification and other clinical characteristics. RESULTS: IS900 PCR detection rate was significantly higher in CD tissue samples (52%) than in UC (2%) or nIBD (5%) specimens (p<0.0001). In CD patients, IS900 DNA was detected in samples from both diseased small bowel (47%) as well as from the colon (61%). No firm association between MAP specific IS900 detection rates and clinical phenotypic characteristics in CD could be established. However, corticosteroid medication constituted a factor which tended to have a negative influence on IS900 DNA detection rates in CD (p<0.01). CONCLUSIONS: The presence of MAP specific IS900 DNA is a predominant feature of CD. Therapeutic intervention against MAP might represent a potential target for disease mitigation in Crohn's disease.     

Specific detection of Mycobacterium paratuberculosis DNA associated with granulomatous tissue in Crohn's disease.

The role of mycobacteria, specifically Mycobacterium paratuberculosis, in Crohn's disease has aroused considerable controversy for many years. Using the ultra sensitive polymerase chain reaction some studies have reported detection of M paratuberculosis DNA in as many as 65% of Crohn's disease patients but also in patients without disease. Other studies have been negative for both groups. We therefore designed a double blind control trial to investigate the presence of mycobacterial DNA in age, sex, and tissue matched paraffin wax embedded tissues from 31 Crohn's disease tissues, 20 diseased gut control tissues, and 10 ulcerative colitis tissues. The specimens were coded and analysed blind with three separate polymerase chain reactions (PCR) based on DNA sequences specific for M paratuberculosis (IS900), M avium (RFLP type A/1) (IS901), and the Mycobacterium genus (65 kDa gene, TB600). The number of granulomata and presence of acid fast bacilli in each Crohn's disease tissue was also investigated. The sensitivity of the system was determined using similarly prepared gut tissue from an animal infected with M paratuberculosis. Four of 31 Crohn's disease tissues and none of the 30 control and ulcerative colitis derived tissues amplified M paratuberculosis DNA. Crohn's disease tissues containing granulomata were significantly more likely to amplify M paratuberculosis specific DNA on PCR than the non-Crohn's disease tissues (p = 0.02). All the positive Crohn's disease tissues contained granulomata, and none contained acid fast bacilli. Equivalent numbers of Crohn's and non-Crohn's disease tissues amplified the region of the 65 kD gene on PCR for non-specific mycobacterial DNA (11/31 and 9/30 respectively). No sections produced an amplified product with the IS901 PCR. These results suggest that few Crohn's disease gut biopsy sections contain M paratuberculosis DNA in association with granulomata. The absence of such DNA in any control and ulcerative colitic tissue strengthens the case for it having a specific association, which may be pathogenic, with Crohn's disease in this minority of patients.     

Identification of Mycobacterium avium pathogenicity island important for macrophage and amoeba infection

The ability to infect macrophages is a common characteristic shared among many mycobacterial species. Mycobacterium avium, Mycobacterium tuberculosis, and Mycobacterium kansasii enter macrophages, using the complement receptors CR1, CR3, CR4, and the mannose receptor. To identify M. avium genes and host cell pathways involved in the bacterial uptake by macrophages, we screened a M. avium transposon mutant library for the inability to enter macrophages. Uptake-impaired clones were selected. Sequence of six M. avium clones identified one gene involved in glycopeptidolipid biosynthesis, one gene encoding the conserved membrane protein homologue to the M. avium subsp. paratuberculosis MAP2446c gene and four others belonging to the same region of the chromosome. Analysis of the chromosome region revealed a pathogenicity island inserted between two tRNA sequences with 58% of G+C content versus 69% in the M. avium genome. The region is unique for M. avium and is not present in M. tuberculosis or M. paratuberculosis. Although the mutants did not differ from the WT bacterium regarding the binding to macrophage cell membrane, analysis of macrophage proteins after 1 h infection revealed a deficiency in the mutant to phosphorylate certain proteins on uptake. To understand M. avium interaction with two evolutionarily distinct hosts, the mutants were evaluated for Acanthamoeba castellanii invasion. The defect in the ability of the mutants to invade both cells was highly similar, suggesting that M. avium might have evolved mechanisms that are used to enter amoebas and human macrophages.