Specificity of insertion sequence-based PCR assays for mycobacterium tuberculosis complex.

OBJECTIVE: To determine the specificity of different insertion sequence-targeted polymerase chain reaction (PCR) tests for Mycobacterium tuberculosis complex. DESIGN: One M. bovis BCG strain, two M. tuberculosis strains and ten species of mycobacteria other than tuberculosis (MOTT) were tested by three PCR assays based on the repetitive elements IS6110, IS1081 and IS990 under variable amplification conditions (different temperatures of primer annealing and numbers of reaction cycles). RESULTS: DNA amplifications based on the three insertion sequences yielded fragments of expected sizes only in DNA from M. tuberculosis complex strains when the tests were conducted at high stringency (65 degrees C). At the annealing temperature of 60 degrees C the PCR assay with IS6110-specific primers yielded a 245 bp fragment also in nine MOTT strains tested. This could result from previously reported homology between non-tuberculous mycobacteria and a central region of IS6110. Amplification assays based on IS1081 and IS990 gave false-positive results in some MOTT isolates only under very low stringency (55 degrees C), which could be due to non-specific priming of the target DNA at that temperature. CONCLUSION: Repetitive elements IS1081 and IS990 may represent a more reliable alternative to the more widely used IS6110 PCR target for tuberculosis diagnosis.     

Detection of M. tuberculosis in clinical samples of diversified nature by IS6110 based PCR

Performance of the polymerase chain reaction technique based on IS6110 sequence was evaluated in clinical samples obtained from pulmonary and extrapulmonary cases of tuberculosis. One hundred and seventy two samples were processed for detection of M. tuberculosis by ZN stained smear examination, LJ medium culture, BACTEC radiometric culture and PCR tests amplifying 123bp region of IS6110 sequence. A significant difference was seen in the sensitivities of different tests, the figures being 83% for PCR test, 35.2% for smear examination, 47.16% for LJ culture and 53.45% for BACTEC culture (p < 0.05). However, no significant difference was found as far as specificity was concerned. PCR test sensitivity in. pulmonary and extrapulmonary clinical samples were 90.14% and 77.27% respectively and found to be significantly higher (p < 0.05) when compared with those of other tests. The mean detection time for M. tuberculosis was 24.03 days by LJ medium culture, 12.89 days by BACTEC culture and less than one day by PCR test. PCR based on IS6100 sequence is highly sensitive method for the early diagnosis of pulmonary and extrapulmonary tuberculosis.     

Development and evaluation of a multiplex polymerase chain reaction for the detection of Mycobacterium tuberculosis from pulmonary specimens

Abstract Background: The diagnosis of pulmonary tuberculosis is still a major challenge. Using a polymerase chain reaction (PCR), one can detect Mycobacterium tuberculosis in clinical samples within a few hours. However, single gene targets may result in false negativity due to the absence of target DNA in some M. tuberculosis isolates. The objective of this study was to develop and evaluate a multiplex PCR (M-PCR) using IS6110 and devR primers for the detection of M. tuberculosis in sputum samples. Methods: Sputum samples were collected from: (1) 200 confirmed cases of tuberculosis; (2) 100 suspected cases of tuberculosis diagnosed on the basis of clinical and radiological findings; (3) 200 non-tubercular patients suffering from respiratory diseases other than tuberculosis, in whom tuberculosis had been excluded. All 500 sputum samples were subjected to PCR using IS6110 primers, and M-PCR using IS6110 and devR primers; results were compared with conventional techniques. Results: It was found that M-PCR was 97.5% successful in detecting the presence of tuberculosis in the confirmed tuberculosis group as compared to 84.5% by IS6110-based PCR. In the suspected tuberculosis group, M-PCR could detect 45% of cases as compared to 40% by IS6110-based PCR. Overall, the specificities of both the PCR and M-PCR were found to be 96.5%. Conclusions: This study demonstrated that the M-PCR assay is more sensitive than the IS6110-based PCR for the detection of M. tuberculosis in sputum specimens and could be applied in situations of highly suspected tuberculosis when all others tests including IS6110 PCR are negative.     

结核分枝杆菌IS6110序列在石蜡组织中的检测、克隆与测序

目的：探讨套式-聚合酶链反应（Nested-PCR)检测石蜡组织中结核分枝杆菌的特异性和敏感性。方法：采用套式-PCR检测石蜡包埋组织中结核菌复合体特异插入序列IS6110，并对部分标本的PCR产物进行克隆和测序。结果：31例结核标本石蜡组织检出结核菌DNA共28例，套式-PCR的敏感度为90.3%,特异度为100%。阳性预测值为100%。随机选取两例PCR产物没是序结果与结核菌标准株H37Rv同源性分别为97%和95.3%。结论：套式-PCR检测常规石蜡包埋组织中结核菌IS6110序列具有特异性强和敏感性高的特点，可应用于临床诊断，尤其是对那些常规苏木精-伊红染色和抗酸染色无法确诊的病例更具意义。     

Comparative evaluation of IS6110 PCR via conventional methods in rapid diagnosis of new and previously treated cases of extrapulmonary tuberculosis

In developing countries the diagnosis of extrapulmonary tuberculosis (EPTB) is a major burning challenge. EPTB encounters many problems like pauci-bacillary nature, inadequate specimen volume. All the limitations reflect in the poor contribution of conventional bacteriological technique in the establishment of diagnosis of EPTB. Nucleic acid amplification methods are rapid and sensitive has modified strategies for the detection of mycobacterial DNA. A fragment of DNA of 123 bp belonging to insertion sequence IS6110 based on specific gene of Mycobacterium tuberculosis complex was amplified by polymerase chain reaction (PCR) for the rapid diagnosis of EPTB. The present study was to comparative evaluation of IS6110 PCR via conventional methods in the rapid diagnosis of new and Previously treated cases of extra pulmonary tuberculosis. Four hundred fifty specimens were collected from suspected cases of EPTB were processed for Mycobacteria by Zeihl Neelson (ZN) staining and BACTEC culture for M. tuberculosis. All the specimens were also processed for IS6110 based PCR amplification with primers targeting 123 bp fragment of insertion element IS6110 of M. tuberculosis complex. We found significant difference was seen in sensitivities of different tests. Of these 450 specimens, 60 (13.4%) were positive for AFB by ZN staining, 202 (45%) for BACTEC culture and IS6110 PCR were positive for M. tuberculosis complex in 283 (63%) specimens (p< 0.05). However, there was no significant difference (p< 0.05) as far as specificity of different tests. We found that IS6110 PCR has higher sensitivity than smear microscopy and BACTEC culture in both cases of new cases as well as in previously treated cases. IS6110 PCR can be highly useful in diagnosis of new and treated cases of EPTB. It may facilitate therapeutic decisions for those with suspected of EPTB.     

Comparison of microplate hybridization with gel electrophoresis and dot blot hybridization for the rapid detection of Mycobacterium tuberculosis PCR products

A microplate ELISA hybridization assay has been developed for the detection of the IS6110 PCR products of M. tuberculosis from sputum specimens. In this study, its efficacy was evaluated by comparison with agarose gel electrophoresis (AGE) and dot blot hybridization (DBH), with culture results as the 'gold standard'. The assay was used with 190 sputum samples: the PCR results detected by ELISA and AGE showed close agreement, with sensitivity, specificity and accuracy of 90%, 100% and 96% respectively. The same values for DBH were 92%, 98% and 96% respectively. The validities of these methods were not statistically significantly different (p>0.05). The agreement rates of PCR product detection by AGE comparing with DBH and ELISA were 0.964 and 0.964 respectively, while that of DBH and ELISA was 1.0 by Kappa analysis. The overall agreement was not statistically significantly different (p>0.05). Use of DBH or ELISA hybridization increased the sensitivity of detection by AGE 10-fold from 10 pg to 1 pg of purified DNA per reaction; ie from about 30 to about 3 organisms. The amount of PCR product detected by ELISA was only one half of that detected by the other methods; the total assay time of ELISA following the PCR was 4 hours. In conclusion, the microplate hybridization assay may replace AGE and DBH for the detection of the PCR products of M. tuberculosis because of its sensitivity, specificity and accuracy. Additional advantages of the microplate assay over AGE and DBH include rapidity, ease of use, greater safety, cost effectiveness and greater objectivity in the reading of results; the technique is suitable for use in epidemiological studies for the analysis of a large number of samples.     

Evaluation of Amplicor- and IS6110-PCR for direct detection of Mycobacterium tuberculosis complex in Singapore

One hundred and seventy-eight samples from 168 individuals were tested for Mycobacterium tuberculosis complex ( Mtc ) using Amplicor PCR, IS6110 -PCR (in-house), acid fast (AF)-staining and culture. Thirty-one samples were positive by culture, but 37 samples were later resolved to be truly positive for Mtc . Of these, Amplicor detected 32 (86.5%), IS6110 -PCR detected 31 (83.6%), and AF-staining 21 (56.8%). None of the 141 Mtc -negative samples was positive by these tests, thus giving 100% specificity. Although the IS6110 -PCR was more sensitive than Amplicor in detecting spiked Mtc DNA, it was not more sensitive than the latter in detecting Mtc in clinical samples. Reasons likely to account for the PCR false negativity were (i) sample inoculum size, (ii) nonuniform samples due to clumping effect of Mtc and (iii) the absence of target gene sequences for IS6110 -PCR. Culture negativity, on the other hand, was likely to be associated with nonviable Mtc . Amplicor PCR is promising for direct detection of Mtc . The IS6110 -PCR, however, may not be as suitable because of possible existence of IS6110- deleted Mtc strain in Singapore.     

Simultaneous use of two PCR systems targeting IS6110 and MPB64 for confirmation of diagnosis of tuberculous lymphadenitis

PCR has emerged as a powerful technique for detection of various pathogens including Mycobacterium tuberculosis. In present study, eighty one samples of lymph node biopsies from clinically suspected cases of tuberculous lymphadenitis were examined for AFB, culture on L?wenstein Jensen medium and simultaneous use of two PCRs targeting IS6110 and MPB64. Positivity with M. tuberculosis culture and AFB was 13.6% and 28.4% respectively. All samples culture positive for nontuberculous mycobacteria were negative by both PCR systems. Higher proportion of positive results were observed with PCR targeting IS6110 by which 56 of 81 (69.1%) samples showed positive results as compared to PCR targeting MPB64 by which 39 of 81 (48.2 %) samples showed positive results. When combined, 63 out of 81 (77.8%) samples were detected positive for M. tuberculosis DNA. However, 7/81 (8.6 %) samples remained negative by IS6110 but positive by MPB64 method. Thus our data suggest that the use of one additional PCR (other than IS6110 system) can reduce false negativity of PCR results in the samples harboring zero copy of IS6110 element which is known to exist in Indian population.     

Analysis of rate of change of IS6110 RFLP patterns of Mycobacterium tuberculosis based on serial patient isolates.

The rate of change of IS6110 restriction fragment length polymorphism (RFLP) patterns of Mycobacterium tuberculosis was determined in serial isolates from 544 patients. In 25 patients (4.6%), the RFLP patterns of the follow-up isolates differed from the initial isolates. Patients with different follow-up strains were less likely to cluster with patients whose strains had indistinguishable RFLP patterns. Changes in RFLP patterns were more common for persons with extrapulmonary disease and for those who had both pulmonary and extrapulmonary isolates. Based on serial isolates spanning for the most part <3 months, the half-life was extrapolated to be 3.2 years (95% confidence interval, 2.1-5.0). The main implication of this study is that the rate of change of IS6110-based RFLP of M. tuberculosis supports the use of IS6110 typing in epidemiologic studies of recent transmission of tuberculosis.     

Characterization of the phylogenetic distribution and chromosomal insertion sites of five IS6110 elements in Mycobacterium tuberculosis: non-random integration in the dnaA-dnaN region.

SETTING: Five IS6110 chromosomal insertion sites were characterized in the multidrug resistant Mycobacterium tuberculosis 'W' strain. OBJECTIVE: To use insertion site probes to study the phylogenetic distribution of IS6110 in the M. tuberculosis genome. DESIGN: A total of 722 M. tuberculosis isolates, previously genotyped using the standard IS6110 Southern blot hybridization methodology, were re-hybridized with the Region A insertion site probe and representative strains were further hybridized with the Region B and C probes. Strains were grouped on the basis of having IS6110 insertions in these different regions and their relatedness was further compared by sequencing the IS6110 insertion sites. RESULTS: The insertion site probes revealed that the collection of Chinese isolates previously grouped as the Beijing strain family shared IS6110 insertions in common with the W and other genotypic group 1 strains. Unexpectedly, we found that IS6110 integrated at least 10 independent times between the dnaA and dnaN genes encoding deoxyribonucleic acid replication proteins. CONCLUSIONS: IS6110 insertion site mapping is able to identify genetic relatedness among a collection of M. tuberculosis clinical strains representing the breadth of species diversity. The mapping data indicate that IS6110 insertion sites are not always random.     

Rapid and efficient detection of extra-pulmonary Mycobacterium tuberculosis by PCR analysis.

SETTING: The diagnosis of extra-pulmonary tuberculosis (EPTB) remains an important clinical problem, primarily because of the inadequate sensitivity of conventional bacteriologic methods for detecting Mycobacterium tuberculosis in extra-pulmonary specimens. OBJECTIVE: To evaluate whether a IS6110-based polymerase chain reaction (PCR) method can be utilized to detect M. tuberculosis in non-pulmonary specimens. DESIGN: Specimens from 286 Mexican patients with a presumptive clinical diagnosis of EPTB were prospectively examined by Ziehl-Neelsen staining, mycobacterial culture on L?wenstein-Jensen slants, and by PCR. The DNA for PCR was extracted by the buffer lysis method and phenol-guanidine thiocyanate-chloroform. Primers that amplify a 200 bp fragment from the insertion-like M. tuberculosis sequence element IS6110 were utilized. RESULTS: Our results demonstrate that this PCR method is highly specific (100%) for identifying M. tuberculosis from a variety of specimens including cerebrospinal fluid (CSF), pleural fluid, ascitic fluid, pericardial fluid, urine, and lymph node exudate. Moreover, the sensitivity of PCR for detecting M. tuberculosis in CSF (94%), pleural fluid (94%), ascitic fluid and other extrapulmonary specimens (93%) greatly exceeds the sensitivity of conventional smear and culture methods. CONCLUSION: These results demonstrate that PCR can be a highly specific and sensitive aid in the detection of M. tuberculosis from extra-pulmonary specimens.     

利用PCR技术检测537份新疆结核病人痰标本中的结核分枝杆菌

目的 提高聚合酶链反应在检测人结核分枝杆菌中的特异性和敏感性。方法 在聚合酶链反应中对4种DNA片段即结核杆菌特异插入列IS6110,IS1081,和16SrRNA,65kDa摸板进行了比较;为获取较多的细菌DNA,临床痰标本处理采用了国际标准化方法主要包括用一定量的N－乙酰－L半胱胺酸和氢氧化钠处理痰标本;改进了RCR混和液的成份即添加了甘油,dUTP－尿嘧啶糖基化酶。结果 选择IS6110作为结核杆菌特异性摸板用于检测细菌DNA,制备出了6批人结核杆菌PCR检测试剂盒,在对来自新疆结核病研究所的537份痰标本的检测中发现,谝试剂盒检测的特异性为65.97%,敏感性为93.53%。结论 改良TB－PCR试剂盒显示有较高的敏感性,特异性还有待于进一步完善,该试剂盒在临床诊断中有一定的价值。     

Disruption of coding regions by IS6110 insertion in Mycobacterium tuberculosis.

SETTING: The insertion sequence IS6110 is widely used as a DNA fingerprinting probe for the classification of Mycobacterium tuberculosis strains. This study has focused on the characterization of regions disrupted by insertion of the IS6110 element. OBJECTIVE: To characterize IS6110 insertion loci in clinical isolates of M. tuberculosis, in terms of their genomic location and genetic identity, to ascertain whether IS6110 transposition could be a mechanism driving phenotypic change. DESIGN: Thirty-three IS6110 insertion loci were cloned from 8 clinical isolates of M. tuberculosis. Clones representing DR locus insertions were identified by hybridization (n = 4), and all other clones were characterized by DNA sequencing (n = 29). The sequence data was analyzed in conjunction with that of 43 other insertion loci identified in published literature and DNA sequence databases. RESULTS: The 76 sequences analyzed represented 66 unique insertion loci (including 9 unique insertions into the ipl locus). When mapped to the H37Rv genome, the majority of unique insertion loci demonstrated disruption of coding regions by IS6110 (n = 42; including the ipl insertions), while the remainder either occurred within intergenic regions (n = 17), or could not be mapped to the H37Rv genome sequence (n = 7). Mapping of the insertion loci reveals distribution throughout the chromosome, with isolated preferential insertion loci. CONCLUSIONS: This study has demonstrated the occurrence of 66 unique IS6110 insertion loci dispersed throughout the M. tuberculosis genome, with an unexpectedly high incidence of IS6110 insertions occurring within coding regions. However, the IS6110-mediated coding region disruptions identified here may only have limited impact on phenotype, as most of the coding regions disrupted are members of multiple gene families. Disruption of individual members of a family of genes may have no effect on phenotype or could have a minor or major impact, depending on the specificity and activity of the encoded protein.     

The IS6110 repetitive DNA element of Mycobacterium tuberculosis is not detected in exhaled breath condensate of patients with active pulmonary tuberculosis

BACKGROUND: A large tertiary referral hospital in inner-city Chicago. OBJECTIVES: To determine whether the IS6110 repetitive DNA element of Mycobacterium tuberculosis is detected in exhaled breath condensate of patients with newly diagnosed active pulmonary tuberculosis. METHODS: Ten hospitalized patients with positive Ziehl-Neelson-stained sputum smears were studied. Concurrent sputum cultures for mycobacteria were performed as well. Exhaled breath condensate was collected from each patient within 6 days of initiating antituberculosis chemotherapy (median 1.5 days). These samples were analyzed by polymerase chain reaction (PCR) using primers designed to amplify the IS6110 DNA fragment of M. tuberculosis. Exogenous M. tuberculosis DNA was added to exhaled breath condensate samples to detect PCR inhibitors. Concurrent cultures of exhaled breath condensate for mycobacteria were performed. RESULTS:M. tuberculosis was identified in 9 of 10 sputum cultures. One isolate was identified as Mycobacterium kansasii. The IS6110 repetitive DNA element of M. tuberculosis was not detected in any of the 10 exhaled breath condensate samples. Exogenous M. tuberculosis DNA added to these samples elicited the characteristic band pattern of M. tuberculosis on agarose gel electrophoresis. No PCR inhibitors were detected. Cultures of exhaled breath condensate showed no growth of mycobacteria. CONCLUSIONS: The IS6110 repetitive DNA element of M. tuberculosis is not detected in exhaled breath condensate of patients with newly diagnosed active pulmonary tuberculosis.     

IS6110-RFLP and spoligotyping of Mycobacterium tuberculosis isolates in Iran

To evaluate and compare the usefulness of IS6110-restriction fragment length polymorphism (RFLP) and spoligotyping in the epidemiology of tuberculosis in Iran, Mycobacterium tuberculosis complex strains, isolated in 2 different areas of Iran, were subjected to RFLP and spoligotyping. The average number of IS6110 copies per strain was 11 and ranged from 5 to 18 among the M. tuberculosis strains. In total, among the 62 isolates, 56 different patterns were observed. 50 strains had unique RFLP patterns (89%) and 12 (11%) revealed patterns that were found among at least 1 other isolate. Spoligotyping of 97 isolates resulted in 42 different patterns, of which 72% were found in 15 clusters. 14 (29%) out of 48 investigated isolates were resistant to 1 or more antituberculosis drugs and 57% of the resistant isolates were isolated from Afghan immigrants. Ten percent of the isolates represented the Beijing genotype, including 4 of the 14 (36%) resistant strains. Three of these resistant Beijing strains were isolated from Afghan patients. IS6110-RFLP typing could be useful for studying the epidemiology of tuberculosis in Iran. IS6110 patterns were polymorphic and the average IS6110 copy number was high.     

PCR指印技术对新疆结核病病原Bacter460液体培养标本进行菌株分型

以结核分枝杆菌特异插入序列IS6 110两端序列为模板 ,设计一对外向PCR引物进行PCR扩增 ,从而建立一种结核分枝杆菌的快速分子生物学分型技术 ,该试验的基础是利用IS6 110在结核分枝杆菌染色体DNA中反复重复且IS6 110序列之间相距较近 ,经PCR扩增呈现多条带型构成DNA指印。在对新疆结核病人的 31份液体培养标本的PCR检测呈现 6种指印 ,该PCR分型技术对结核分枝杆菌的分型所需时间短 ,不需细菌再培养 ,DNA纯化和酶切、萨瑟恩转印或核酸杂交等繁琐步骤。证明该法是一种快速、准确的鉴定与分型方法并可直接进行分子流行病学研究     

IS1607, a single-copy insertion sequence-related element of the Mycobacterium tuberculosis complex.

The species specificity of IS1607, a new Mycobacterium tuberculosis complex insertion sequence-related element, was investigated. IS1607 was present as a single copy in M. tuberculosis, M. bovis and M. bovis BCG strains. This sequence also existed in M. africanum and M. microti, but was not present in 69 strains of 19 atypical mycobacterial species analyzed by using polymerase chain reaction (PCR) or Southern hybridization assay. IS1607 appears to be specific for the M. tuberculosis complex.     

Molecular fingerprinting of Mycobacterium tuberculosis strains isolated in Vietnam using IS6110 as probe.

SETTING: Northern and Southern areas of Vietnam. OBJECTIVE: To study the correlation between DNA fingerprinting of 168 Mycobacterium tuberculosis strains isolated from patients with a particular historical past (political separation of Vietnam for 20 years) and data about geographical origin, drug susceptibility, HIV infection and BCG vaccination status. METHODS: Comparison of restriction fragment length polymorphism (RFLP) patterns produced by Southern hybridization of Pvull-digested chromosomal DNA. RESULTS: The number of IS6110 copies for the 168 strains ranges from 0 to 23. Strains originating from the North or the South differ strongly with respect to the number of copies of IS6110. Indeed, the strains originating from the north have predominantly from 3 to 14 IS6110 copies while the southern strains have predominantly from 15 to 23 IS6110 copies. Furthermore, strains isolated in the North are dispersed into 6 groups whereas 80% of the strains isolated in the South form a single group. Moreover, the prevalence of drug resistance is higher in strains isolated in the South than in the North. No noticeable correlation is observed between RFLP patterns, drug susceptibility, or HIV infection. CONCLUSION: The IS6110 fingerprints of 168 M. tuberculosis strains isolated in Vietnam showed a high range of polymorphism. Only a few strains have been found with no IS6110 (1.8%). The differences between the strains from the North and South, having more than six IS6110, suggests that they derived from ancestral strains that would be distinguishable by the number of IS6110 and their transposition sites throughout the genome. The genomic structure of the population of strains from South Vietnam resembles that of the Beijing strain population. This could account for a similar evolution of M. tuberculosis due to a selection by BCG-induced immunity in the two populations.     

结核性腹膜炎的实验室诊断

目的评价聚合酶链反应（ＰＣＲ）结合Ｓｏｕｔｈｅｒｎ杂交技术及酶联免疫吸附试验（ＥＬＩＳＡ）对结核性腹膜炎的诊断价值。方法用ＰＣＲ结合地高辛标记核酸探针Ｓｏｕｔｈｅｒｎ杂交技术检测４２例结核性腹水中结核分支杆菌ＤＮＡ，并与常规细菌学检测及ＥＬＩＳＡ对比。引物来自结核分支杆菌特异重复插入序列ＩＳ６１１０。特异性通过杂交及限制性内切酶ＳａｌⅠ酶切证实。同时比较了Ｓｏｕｔｈｅｒｎ杂交检测与凝胶电泳检测的敏感性。结果ＰＣＲ的敏感性为６９％，ＥＬＩＳＡ为７１％，培养为９％，涂片镜检均为阴性。并发现杂交较凝胶电泳检测更敏感。结论ＰＣＲ和ＥＬＩＳＡ法对结核性腹膜炎有较高的诊断价值，但前者更具有特异性。将Ｓｏｕｔｈｅｒｎ杂交技术与ＰＣＲ技术结合，可进一步提高检测的敏感性和特异性。     

吉林市结核分支杆菌IS6110 DNA指纹图谱特征分析

目的　分析吉林市结核分支杆菌IS6110 RFLP图谱特征。方法 对53株结核分支杆菌分离株进行IS6110基因分型,得到IS6110 RFLP图谱;按菌株指纹特征的同源性高低予以分组,并进行分析。结果 吉林市结核分支杆菌IS6110 RFLP图谱特征为：(1)IS6110拷贝数目平均为13个;(2)A、B两组同源性很高,具有“北京基因型”特征,C组多态性较强;(3)IS6110 RFLP图谱特征分布无地域差异;(4)耐药菌株与敏感菌株图谱特征无明显差异,但初治耐药菌株成簇率较高。结论 吉林市结核分支杆菌IS6110RFLP图谱特征以“北京基因型”为主;但还具一些独有的特征。