Ethambutol resistance testing by mutation detection.

OBJECTIVE: To identify chromosomal mutations that confer resistance to ethambutol (EMB) in Mycobacterium tuberculosis. DESIGN: Drug-resistant (n = 235) and drug-susceptible (n = 117) M. tuberculosis isolates collected from the Western Cape in South Africa were subjected to embB gene analysis and the results were compared to phenotypic EMB testing. RESULTS: Genotypic analysis identified mutations at codon 306 of the embB gene in 20% (47/235) of the resistant isolates in comparison to only 1.7% (4/235) of those that were phenotypically resistant to EMB by the agar diffusion method. No gene mutations were detected in susceptible isolates. Phenotypic retesting in BACTEC demonstrated that the 47 genotypically resistant isolates were phenotypically resistant to EMB. This implies that 91.4% (43/47) of EMB resistance had been phenotypically missed by routine laboratory procedures. EMB resistance was closely linked to multidrug resistance (MDR); 87.2% (41/47) of the EMB-resistant isolates were resistant to both isoniazid and rifampicin. A newly developed one-step amplification refractory mutation system polymerase chain reaction (ARMS-PCR) method correctly detected the EMB-resistant genotype. CONCLUSION: Implementation of more accurate diagnosis of EMB resistance may enhance patient management in South Africa, as standardised treatment of MDR-TB with second-line drugs is currently dependent on the outcome of the EMB resistance test.     

Molecular characterization of drug-resistant mycobacterium tuberculosis isolates from Sichuan Province in china

Tuberculosis is still a severe public health issue in eastern Asia, and Sichuan is the key area for tuberculosis control in China. To determine the phenotypic and mutation patterns of drug resistance in Mycobacterium tuberculosis isolates from Sichuan, the drug susceptibility of 198 clinical isolates was examined. Among these isolates, 76 drug-resistant and 20 susceptible isolates were analyzed for the rpoB, embB, and katG and inhA regulatory regions. These are mutations believed to associate with rifampin (RIF), ethambutol (EMB), and isoniazid (INH) resistance, respectively. Of the 60 RIF-resistant isolates, 54 (90.0%) carried mutations on the amplified fragment of the rpoB gene, and the most common one (64.8%, 35/54) was at codon 531. Two new mutation patterns were recognized: one isolate harbored three mutations at codons 511, 516, and 518, and the other carried the dual mutation GAChACC at codon 516. A total of 30 INH-resistant isolates (60.0%, 30/50) had mutations at codon 315, whereas 4 (8.0%) had mutations at the inhA regulatory region. Among the 46 EMB-resistant isolates, 22 harbored the Met306 mutation. The results showed geographical variation in the mutation types of drug-resistant genes in M. tuberculosis isolates from Sichuan; this finding is valuable for the development of targeted and rapid molecular diagnostic methods suitable for specific regions.     

特异性核酸内切酶检测结核分枝杆菌的乙胺丁醇耐药基因突变

目的 探讨Surveyor酶法在结核分枝杆菌耐药基因突变中的应用.方法 采用Surveyor酶法检测结核分枝杆菌临床分离株60株,其中已经测序证实有embB基因突变的乙胺丁醇耐药株45株,无基因突变的敏感株15株.经聚合酶链反应扩增,杂交形成异源双链,Surveyor酶切,通过聚丙烯酰胺凝胶电泳判断其有无突变存在.结果 15株敏感株均无embB基因突变,45株耐药株均存在embB基因突变热点306位密码子的点突变,其中33株为ATG→GTG,3株为ATG→ATT,5株为ATG→ATA,2株为ATG→ATC,2株为ATG→CTG.经Surveyor酶法测定,45株embB基因突变株均呈现2条带形,15株敏感株均显示1条带形.结论 Surveyor酶法与测序法的结果完全相符.采用Surveyor酶法进行异源双链分析,具有简便、稳定、低耗、灵敏性和特异性高的特点.     

贵阳市结核分枝杆菌链霉素和乙胺丁醇耐药相关基因突变的检测与分析

目的了解贵阳市及周边地区结核分枝杆菌链霉素和乙胺丁醇耐药相关基因rpsl、rrs和embB的突变特征。方法对39株结核分枝杆菌临床分离株(乙胺丁醇和链霉素均耐药菌株19株,均敏感菌株20株)的rpsl、rrs和embB基因片段进行PCR扩增和测序,以H37Rv菌株序列为参考,比较耐药菌株和敏感菌株的突变特征。结果19株耐药菌株中有14株检出rpsl基因突变,突变率为73.7%(14/19),其中12株为AAG43AGG突变,1株为AAG43AAT突变,1株为AAG88AGG突变;20株敏感菌株中有1株发生rpsl基因AAG43AGG突变,突变率为5.0%;耐药菌株和敏感菌株均未检测出rrs基因突变。19株耐药菌株中有16株检出embB基因突变,突变率为84.2%(16/19),突变包括6株ATG306GTG突变,ATG306ATA、ATG306ATT和ATG306ATC突变各1株; GGC406GCC和GGC406AGC突变各3株,1株CAG497CGG突变;20株敏感菌株未检测出突变。结论贵阳地区结核分枝杆菌菌株链霉素和乙胺丁醇耐药相关基因突变具有多样性;优势突变分别为rpsl43和embB306位点突变。     

2005年和2015年结核分枝杆菌乙胺丁醇耐药水平的变化

目的 探讨2005年和2015年结核分枝杆菌对乙胺丁醇(ethambutol,EMB)耐药水平和突变位点的变化情况以及不同突变类型与EMB耐药水平的关系。方法 选取63株2005年、76株2015年的临床分离的耐多药结核分枝杆菌(MDR-TB)为研究对象,采用微孔板阿尔玛蓝显色法(micro plate alamar blue assay, MABA)检测菌株对乙胺丁醇的最小抑菌浓度(minimum inhibitory concentration, MIC)。然后提取核酸并扩增embB基因全序列,对扩增产物进行测序并分析其突变位点。结果 2005年和2015年MDR对EMB的耐药率无统计学差异(χ²=0.105,P=0.745),embB突变类型变化也无明显差别(χ²=9.410,P=0.124)。2005年选取的菌株中,对EMB耐药的有57株,耐药率为90.48%。2015年选取的菌株中对EMB耐药的有71株,耐药率为93.42%。139株MDR中发现embB基因序列上有9个不同位点突变形式,embB突变型合计99株,占所有MDR的71.22%,野生型40株,占所有MDR的28.78%。突变型对EMB的耐药率为99%,野生型对EMB耐药率为75%。结论 embB基因和embB306基因对检测EMB耐药有一定的参考价值。     

痰耐药结核分枝杆菌embB基因的快速检测及乙胺丁醇耐药机制研究

目的快速检测痰耐药结核分枝杆菌embB基因及了解乙胺丁醇（EMB）耐药的分子机制。方法用PCR方法直接从耐药肺结核患者痰及临床分离菌株扩增embB基因片段,对扩增获得的embB基因片段进行序列测定,比较分析全耐、对EMB敏感的耐多药、对EMB耐药的耐多药、全敏感或标准结核分枝杆菌株之间的基因序列差异。结果于6小时内从耐药肺结核痰中快速检测到embB基因。从所有临床分离菌株均扩增获得847bp片段,序列测定比较发现,全耐菌和对EMB耐药的耐多药菌株均检测有embB基因点突变,突变位点均为第306位密码子ATG突变为ACG,而全敏感株、对EMB敏感的耐多药菌株和标准菌株均未检测到基因突变。结论PCR及序列分析方法可快速、准确检测结核分枝杆菌embB基因及其突变,结核分枝杆菌对EMB的耐药性与embB基因点突变有关。     

耐多药结核分枝杆菌基因突变分析

目的对临床分离的耐多药结核分枝杆菌株进行基因突变分析。方法对耐多药结核分枝杆菌临床分离菌株进行耐药基因的PCR检测,利用基因序列测定方法分析耐药基因突变情况。结果从耐多药结核病（MDR-TB）患者临床分离菌株中快速检测到rpoB、katG、rpsL、embB基因及其突变。耐多药菌株、全耐及单耐利福平分离菌株均检测rpoB基因点突变,突变位点主要为第516、526和531常见密码子,1例MDR-TB出现第479位和第531位密码子同时突变。耐多药菌、全耐菌及单耐异烟肼的菌株均检测有katG基因点突变,突变位点均为第2066位碱基C突变为Go全耐菌和对乙胺丁醇（EMB）耐药的耐多药菌株均检测有embB基因点突变,突变位点均为第306位密码子ATG突变为ACG。全耐菌和对链霉素（SM）耐药的MDR-TB菌株均检测有rpsL基因点突变,突变密码子为CCT突变为CTT,其中从1株对SM敏感的MDR-TB中也检测到突变。全敏感株、标准株及利福平（RIF）、异烟肼（INH）或EMB敏感的耐药株均无rpoB、katG或embB基因突变。结论PCR及基因序列测定可快速检测耐多药结核基因,结核分枝杆菌耐多药性与多个基因突变相关。     

Anti-drug pattern of drug-resistant Mycobacterium tuberculosis and analysis of mutation in drug-target genes

The antimycobacterial susceptibility test was performed and minimal inhibitory concentration (MIC) to drugs was determined in 98 strains of Mycobacteium tuberculosis (MTB) isolated in Tokyo from 2000 to 2003, to find which were resistant to any of the four main anti-MTB drugs, isoniazid (INH), rifampicin (RFP), streptomycin (SM), and ethambutol (EMB). 27strains of them were resistant only to SM, and 16 strains were resistant only to INH. 51 strains of them were resistant to not only INH but also other drugs. 38 strains were resistant to both INH and RFP. 19 strains were resistant to all four drugs, including 7 strains resistant to new quinolon anti-biotics also. Nucleotide or amino-acid mutations in drug resistant MTB genome were determined by DNA sequencing method. Mutation of codon 516, 526, or 531 of rpoB gene was detected in 98% of MTBs resistant to RFP. Deletion or insertion of katG gene or nucleotide mutation at regulatory region of ahpC gene was detected in MTBs highly resistant to INH. Amino acid mutation of katG gene, especially at codon 315, was detected in MTBs resistant to INH intermediate. Nucleotide mutations at regulatory region of inhA gene were detected in MTBs resistant to INH at low level. Amino acid mutation at codon 43 or 88 of rpsL gene was detected in MTBs highly resistant to SM, and nucleotide mutation at 512, 513, or 516 of rrs gene was detected in MTBs resistant to SM at low level. Amino acid mutation at codon 306 of embB gene was detected in 87% of MTBs resistant to EMB.     

结核分枝杆菌耐乙胺丁醇分离株emb B基因突变研究

目的探讨结核分枝杆菌对乙胺丁醇（EMB）产生耐药的分子机制,建立直接快速检测结核分枝杆菌EMB药物敏感性的实验方法。方法采用聚合酶链反应（PCR）扩增技术对临床耐乙胺丁醇结核分枝杆菌进行PCR扩增,扩增产物经纯化后,直接进行DNA测序分析。结果 54例临床分离株中,19例为EMB敏感株,35例为EMB耐药株。35例耐药株中13例（37.1%）发生基因突变。13例基因突变皆为错义突变,且有1例同时发生310位和313位突变。结论 embB306位氨基酸Met被置换是结核分枝杆菌对乙胺丁醇产生耐药性的重要机制,测序分析可以确认耐药基因的突变位点,是快速检测耐乙胺丁醇结核分枝杆菌的快速、有效的方法。     

Identification of MDR-TB Beijing/W and other Mycobacterium tuberculosis genotypes in Nairobi, Kenya.

SETTING: Suspected tuberculosis (TB) patients in Nairobi, Kenya. OBJECTIVE: To identify the presence of multidrug-resistant (MDR) Beijing/W type and other genotypes of Mycobacterium tuberculosis. METHODS: Thirty-three isolates resistant to one or more drugs (resistance ratio method), including 15 MDR isolates and 40 susceptible isolates selected at random, were analysed by dot-blot hybridisation for mutations associated with resistance to isoniazid, rifampicin, streptomycin and ethambutol. All strains were genotypically classified using spoligotyping. RESULTS: Of the 33 drug-resistant isolates, 21 (64%) were from males and 12 (36%) were from females. Mutations associated with resistance to isoniazid (katG 315) and rifampicin (rpoB526, 531) were confirmed in 83.3% and 100% of the isolates, respectively, and in 87% of the MDR isolates. Mutations were detected in 25% and 71.5% of the isolates resistant to streptomycin (rpsL43) and ethambutol (embB306), respectively. No mutations were detected in drug-susceptible isolates. Spoligotyping grouped the isolates into 25 groups. Ten of these groups corresponded to previously identified strain groups, including seven families in the international database. One of these families (CAS1) comprised six (40%) of the 15 MDR isolates. Another family (Beijing) had six (8.3%) isolates, of which two (33.3%) were MDR (Beijing/W). CONCLUSION: This study is the first in Kenya and the second in sub-Saharan Africa to report the presence of MDR Beijing/W type and other possible drug-resistant outbreak strains. Application of the molecular techniques and markers will allow us to monitor the spread of existing drug-resistant strains and the appearance of new ones.     

31株结核分枝杆菌异烟肼耐药相关基因检测及序列分析

目的了解贵阳地区分离的结核分枝杆菌katG基因、inhA启动子和oxyR-aphc间隔区基因突变特征。方法对31株结核分枝杆菌临床分离株（异烟肼耐药株17株,异烟肼敏感株14株）的katG基因、inhA启动子和oxyRaphc间隔区进行DNA片段的PCR扩增,并进行测序分析。结果 17株异烟肼耐药菌株中有16株检出katG基因突变,其中70.5%（12/17）为315位密码子变异,且变异类型均为AGC→ACC,敏感株未发现315位点突变。11株敏感菌和4株耐药菌在463位密码子发生变异,变异类型均为CGG→TGG,变异率分别为78.6%（11/14）和23.5%（4/17）,差异无统计学意义。有12株耐药株的变异类型为katG基因双重位点突变,其中10株为katG315（AGC→ACC）和463（CGG→TGG）位变异,463（CGG→TGG）和299（GGC→AGC）变异及463（CGG→TGG）和419（GAC→CAC）位变异各1株。2株异烟肼耐药菌检出oxyR-aphC启动区G32A突变,其中1株为联合katG463和299位突变。结论贵阳株结核杆菌菌株异烟肼耐药基因突变具有多态性,主要的变异类型为katG315位点突变。     

噬菌体法与BACTEC-960检测结核分枝杆菌乙胺丁醇耐药性的比较研究

目的建立噬菌体生物扩增法(PhaB)快速测定乙胺丁醇(EMB)耐药性,探讨其在结核分枝杆菌(MTB)EMB耐药性测定中的应用价值。方法应用PhaB测定138株MTB临床分离株EMB耐药性,并与BACTEC960药敏试验结果比较,对耐药性测定结果不符合的菌株测定其最低抑菌浓度(MIC)。结果138株MTB临床分离株,BACTEC960测定敏感114株,耐药24株;PhaB测定敏感118株、耐药20株。两种方法测定均为敏感112株,均为耐药18株。共计130株两法测定药敏结果相符,符合率942%;结果不符8株,不符合率58%。如以BACTEC960药敏结果为判断标准,则PhaB检测EMB耐药性的敏感性为750%(18/24),特异性为982%(112/114),阳性预测值为900%(18/20),阴性预测值为949%(112/118),准确性为942%(130/138)。结论PhaB检测EMB耐药性只需3d时间,操作简便,不需特殊仪器设备,可作为MTB的EMB耐药性快速筛选方法。     

Characterization of clinical isolates of Mycobacterium tuberculosis resistant to drugs and detection of RpoB mutation in multidrug-resistant tuberculosis in the Philippines.

SETTING: Retrospective study of Mycobacterium tuberculosis isolates at the STD/AIDS Cooperative Central Laboratory, Philippines. OBJECTIVE: To describe patterns of M. tuberculosis resistance against first-line anti-tuberculosis drugs, and to analyze the rpoB gene codon mutation of rifampicin (RMP) resistant isolates and correlate genotypic and phenotypic patterns. DESIGN: One hundred and sixty-four M. tuberculosis complex isolates were retrieved for phenotypic analysis; 89 were resistant to any anti-tuberculosis drug and 50 were RMP-resistant, whereas 48 were multidrug-resistant (MDR). Of these 48, only 33 were available for genotypic analysis of the rpoB gene. RESULTS: Most drug-resistant isolates were phenotypically resistant to isoniazid (INH) (93%), and the probability of an RMP-resistant isolate becoming MDR was 96%. In 33 MDR isolates, 13 types of mutations in nine independent codons were identified; the most frequently mutated codons were S531L (61%) and G510H (15%), which were present in 76% (25/33) of the isolates. S531L was noted in 85.7% of the RMP + INH + SM resistant isolates, while only 80% of the isolates with INH + RMP, EMB + SM resistance showed this mutation. CONCLUSION: The high probability of RMP isolates being MDR suggests that genetic analysis of RMP resistance is useful in detecting MDR-TB. Worldwide accumulation of findings on circulating MDR-TB strains provides indispensable information about the re-emergence of TB.     

噬菌体法检测结核分枝杆菌乙胺丁醇耐药性的研究

目的 建立噬菌体生物扩增法（PhaB法）快速测定乙胺丁醇耐药性的实验体系,探讨PhaB法在测定结核分枝杆菌乙胺丁醇耐药性的应用价值.方法 应用PhaB法测定115株临床分离结核分枝杆菌耐药性,并与BacT/ALERT 3D药敏试验结果相比较,对耐药性测定结果不一致的菌株测定其最低抑菌浓度.结果 115株结核分枝杆菌临床分离株中经BacT/ALERT 3D测定敏感89株,耐药26株;PhaB法测定敏感93株,耐药22株.两种方法测定均为敏感87株,均为耐药20株,两种方法测定药敏结果相符率为93.0%;结果不符8株,不符合率6.96%.如以BacT/ALERT 3D药敏结果为判断标准,则PhaB法检测乙胺丁醇耐药性的敏感性为76.9%（20/26）,特异性为97.8%（87/89）,阳性预测值为90.9%（20/22）,阴性预测值为93.5%（87/93）,准确性为93.0%（107/115）.结论 PhaB法检测结核分枝杆菌乙胺丁醇耐药性只需3天时间,操作简便,不需特殊仪器设备,可作为结核分枝杆菌乙胺丁醇耐药性快速筛选方法之一.     

Prevalence of katG Ser315 substitution and rpoB mutations in isoniazid-resistant Mycobacterium tuberculosis isolates from Brazil.

SETTING: Four hundred and sixty-eight isoniazid (INH) resistant Mycobacterium tuberculosis isolates recovered from a selected Brazilian population. OBJECTIVE: To check for susceptibility to other chemotherapeutic drugs used in TB treatment, and to ascertain mutations involved in INH and rifampicin (RMP) resistance. DESIGN: Antimicrobial susceptibility to RMP, streptomycin and ethambutol (EMB) was evaluated by the resistance ratio method and pyrazinamide (PZA) by activity assay. Single strand conformation polymorphism (SSCP) and sequence analysis were performed in samples from this panel to confirm mutations in codon 315 of the katG and in a 69-bp region of the rpoB gene. RESULTS: Combined resistance to INH+RMP, INH+ PZA, INH+EMB, and INH+RMP+PZA was shown in respectively 272 (58.1%), 126 (26.9%), 47 (10%), 116 (24.8%) isolates. No katG mutation was found in 19 (39.6%) of 48 strains tested. Ser315Thr substitution was found in 29 (60.4%). All RMP-resistant strains tested (n = 25) showed rpoB mutations. S531L substitution was found in 15 (60%). CONCLUSION: INH-resistant strains isolated from selected Brazilian populations frequently show resistance to other first-line anti-tuberculosis drugs. rpoB mutation was responsible for RMP resistance in all strains. Among INHr strains, katG mutations were shown in only 60.4%. Genetic approaches targeting the rpoB gene but not the katG gene have a high sensitivity to detect resistance among Brazilian M. tuberculosis strains.     

结核分支杆菌五种耐药基因检测的临床应用及评价

目的　检测结核分支杆菌rpoBkatG、rpsL、pncA和embB耐药基因 ,评价其临床应用价值。方法　采用聚合酶链反应 单链构象多态性 (PCR SSCP)分析和药敏试验 (比例法 ) ,了解 10 9例肺结核患者结核分支杆菌耐药情况 ,并分析、比较临床治疗效果。结果　 1/ 2以上的肺结核患者至少耐两种抗结核药物 ,对RFP、INH、SM、PZA和EB总耐药率分别为 80 7%、71 5 %、78 8%、5 7 7%和48 6%。rpoB、katG、rpsL、pncA和embB基因突变率分别为 76%、68%、71%、5 1%和 3 0 %。结核分支杆菌耐药基因突变率与耐药水平联系密切 ,多数结核分支杆菌耐药基因突变易发生在高耐药株 ,也有少数基因突变发生在低耐药株。根据药敏试验和耐药基因检测结果 ,6个月耐多药结核治愈率分别达到 5 4 8%和 62 8% ,治疗效果满意 ,两种方法差异无显著性 (P >0 0 5 )。结论　耐药基因检测指导治疗是一种新探索 ,PCR SSCP方法敏感、特异 ,可以快速检测结核分支杆菌rpoB、katG、rpsL、pncA和embB耐药基因突变 ,可能会成为临床指导用药的好方法     

ahpC基因突变与结核分支杆菌耐异烟肼的研究

目的了解我国结核分支杆菌耐异烟肼（ＩＮＨ）分离株ａｈｐＣ编码基因及其启动子突变情况，研究其与ＩＮＨ耐药关系。方法通过聚合酶链反应（ＰＣＲ）单链构象多态性（ＳＳＣＰ）方法分析６２株结核分支杆菌临床分离株ａｈｐＣ及其启动子基因。以Ｈ３７ＲＶ标准株为对照。结果３２株结核分支杆菌药物敏感株ａｈｐＣ及其启动子基因ＳＳＣＰ均泳动正常；３０株耐ＩＮＨ分离株ａｈｐＣ编码基因ＳＳＣＰ也未见异常；１２株高度耐ＩＮＨ分离株中，５株ａｈｐＣ启动子ＳＳＣＰ泳动异常；１８株低度耐ＩＮＨ分离株的ａｈｐＣ启动子泳动正常。结论结核分支杆菌ａｈｐＣ编码基因与耐ＩＮＨ无关；ａｈｐＣ启动子突变是结核分支杆菌ｋａｔＧ改变、过氧化氢酶缺乏的代偿性变化，也许能作为结核分支杆菌高度耐ＩＮＨ的间接指标。     

Detection of mutations in drug resistance genes of Mycobacterium tuberculosis by a dot-blot hybridization strategy.

SETTING: Mycobacterium tuberculosis isolates from patients in communities endemic for tuberculosis in South Africa. OBJECTIVE: To develop a reliable PCR-based dot-blot hybridization strategy to detect mutations conferring drug resistance. DESIGN: Different loci in six genes associated with drug resistance to isoniazid, rifampacin, streptomycin and ethambutol were selected to develop the PCR-based dot-blot hybridization strategy. RESULTS: Primers and probes to detect mutations at codons 315, 463 (katG) 269 (kasA), 531, 526 (rpoB) 43 (rpsL), 513 (rrs) and 306 (embB) were designed and used to develop a PCR-based dot-blot hybridization strategy. The dot-blot hybridization strategy with wild-type probes can efficiently be used to detect drug resistant mutations since these do not hybridize to mutant loci. Stripped blots and mutant probes can be used to identify the precise mutation. The embB gene (ethambutol resistance) was used to show how the dot-blot strategy can assist with the prediction of drug resistance more accurately. The method is rapid, reproducible, not technically demanding and samples can be done in batches. Additional loci can easily be incorporated. CONCLUSIONS: A PCR-based dot-blot hybridization strategy is described which can accurately identify drug resistant strains and the method is useful for patients at risk and in areas endemic for tuberculosis.     

The resistance to major antituberculous drugs of Mycobacterium tuberculosis strains isolated from the respiratory system specimens of tuberculosis patients in Duzce, Turkey

Through generally curable, tuberculosis (TB) is becoming increasingly resistant to commonly used antibiotics. Drug-resistant and multidrug-resistant (MDR)-TB is a consequence of monotherapy, insufficient drug therapy and national TB control programs. The present study was designed to reveal the resistance to major antimicrobial drugs (isoniazid [INH], streptomycin [SM], ethambutol [EMB], and rifampicin [RIF]) of Mycobacterium tuberculosis isolated from the respiratory specimens of TB patients in Duzce, Turkey. A total of 62 TB patients (46 male, 16 female; age: 17 - 75 mean: 42 +/- 15.9) were included in the study; 52 (83.8%) were new cases and susceptible to all anti-TB drugs, while 10 (16.2%) were previously treated cases. Antimicrobial susceptibility tests were performed by the proportion method in L?wenstein-Jensen medium. Fifty-two of the 62 (83.8%) isolated M. tuberculosis strains were found to be susceptible to all drugs, and 7 (11.3%), 5 (8%), and 3 (4.8%) were resistant to SM, INH, and RIF, respectively; 3 (4.8%) were MDR. There were no EMB-resistant strains. The results of this study show the presence of drug-resistant and MDR strains of TB at Duzce in the northwest part of Turkey.     

结核分支杆菌inhA基因突变的测序研究

目的 对耐药结核分支杆的inhA基因进行测序分析以研究其变异的分子机制。方法 以inhA片段为引物,聚合酶链反应扩增H27Rv、耐药株和敏感株的inhA基因,产物克隆后制备质粒,ABI377全自动核酸测序系统测定DNA序列。结果 在17个耐异烟肼菌株中,11株出现inhA基因变异,突变率为65％,其中在10株至少每株有1个错义突变。变异主要为点突变,包括碱基置换和缺失。各菌株变异不同。katG和inhA同时变异的达62％。首次发现了18个与结核分支杆菌耐INH和EMB特性有关的inhA基因位点。结论 结核分支杆菌耐INH和EMB特性与inhA突变异致药物结合位点减少有关。