结核分枝杆菌L型的诱导及其对抗菌药物的敏感性

目的：观察异烟肼、利福平、乙胺丁醇抗结核药物诱导形成结核分支杆菌L型以及结核分支杆菌L型对抗菌药物敏感性。方法将结核分支杆菌接种于含有不同质量浓度利福平（0．05、0．1、0．2μg/mL）、异烟肼（0．01、0．04、0．08μg/mL）、乙胺丁醇（1、2．5、5μg/mL）的BD960液体培养基内,10 d后在显微镜下观察结核分支杆菌L型的形成情况。培养结核分支杆菌L型,在显微镜高倍镜下观察,并检测其对抗菌药物的敏感性。结果0．1、0．2μg/mL利福平,0．04、0．08μg/mL异烟肼,2．5、5μg/mL乙胺丁醇可诱导形成结核分支杆菌L型。在含有4μg/mL链霉素、0．2μg/mL异烟肼、40μg/mL利福平、2μg/mL乙胺丁醇、1μg/mL对氨基水杨酸的非高渗培养基内培养7 d后均可见结核分枝杆菌L型生长,而含有30μg/mL卡那霉素、40μg/mL卷曲霉素、3μg/mL氧氟沙星的培养基内未见其生长。结论中高浓度的利福平、异烟肼、乙胺丁醇能够诱导结核分支杆菌L型形成。结核分枝杆菌L型对卡那霉素、卷曲霉素、氧氟沙星敏感。     

基因芯片杂交技术在肺结核诊治中的应用

目的探讨基因芯片杂交技术在肺结核诊治中的应用价值。方法运用分枝杆菌菌种鉴定基因芯片检测系统。对结核杆菌阳性的标本进一步做异烟肼、利福平、乙胺丁醇、链霉素四种常用抗结核药物的耐药突变基因检测。结果对基因芯片杂交法检测结核分枝杆菌阳性的29份痰标本做了异烟肼、利福平、乙胺丁醇、链霉素四种常用抗结核药物的耐药突变基因检测。有18份痰标本检出非结核分枝杆菌。结论采用基因芯片杂交法查痰结核杆菌,阳性率明显高于传统的痰涂片,与培养法相比较,当天可出结果,极大地缩短了痰培养法的时间。同时可对目前国内发病率较高的10种分枝杆菌进行菌种鉴定,并可对利福平、异烟肼、链霉素、乙胺丁醇这四种一线抗结核药的耐药基因（rpoB、katG、inhA、rpsL、embB）的多种突变进行检测性。此方法检测快速、准确、特异、敏感,为肺结核的有效诊治提供了重要的技术手段和可靠依据。     

链霉素、异烟肼、利福平、乙胺丁醇和吡嗪酰胺单一的和联合的对结核菌的杀菌作用

作者对肺结核短程疗法中常用的抗结核药物,按近似于病人使用的药物血浓度,系统地观查了这些药物单一的和联合的在试管内杀菌作用。采用液体Tween-白蛋白培养基,以对数期培养的结核菌(H 37 Rv在第4天和为7天平均减少的活菌数为指标。在单一药物中,链霉素杀菌作用最高,利福平和异烟肼次之,至于乙胺丁醇杀菌作用最小,且至少在接触药物4天后才出现杀菌作用。在两药联合中,链霉素和异烟肼、异烟肼和乙胺丁醇、链霉素和利福平有协同作用或附加作用;异烟肼和利福平、链霉素和乙胺丁醇之间互无作用;利福平和乙胺丁醇、     

结核分支村菌耐药分子机制及快速检测的研究

目的：研究结核分支杆菌异烟肼、利福平耐药的分子机制，探索快速检测结核分支杆菌异烟肼、利福平耐药性的分子生物学方法。方法：应用聚合酶反应－单链构象多态性（PCR-SSCP）检测结核分支杆菌异烟肼、利福平耐药株与katG基因、rpoB基因突变。结果：46株结核分支杆菌临床分离株均未发现katG基因序列的缺失，30株异烟肼耐药株中，17株检测到katG基因突变，耐药株中katG基因的突变率为57％；87株结核分支杆菌利福平耐药临床分离株的PCR－SSCP结果显示，所有39株利福平敏感菌无突变检出，48株利福平耐药菌中，36株高度利福平耐药菌和7株低度利福平耐药菌检测量到rpoB基因突变；利福平耐药株中rpoB基因的突变检出率为89．6％。结论：证实katG和rpoB基因突变分别是结核分支杆菌异烟肼和利福平耐的主要分子机制。应用聚合酶链反应－单链构象多态性（PCR－SSCP）可快速检测结核分支杆菌异烟肼、利福平耐药性。     

分支杆菌药物敏感性测定的几个问题

非结核分支杆菌病的治疗和药物敏感性测定最初是模仿结核病的治疗和结核分支杆菌药敏试验。但是,非结核分支杆菌在药物敏感性方面存在一些自己的特征。因此,与结核分支杆菌药敏试验方法有所不同。目前对分支杆菌药物敏感性研究尚欠深入,对其规律性认识不清,结果不令人满意。一、分支杆菌药物敏感性特征就其对药物敏感性而言,非结核分支杆菌存在三个特点:(1)药物敏感度幅度大,分布散。结核分支杆菌野生株对利福平、异烟肼、乙胺丁醇、链霉素、氧氟沙星等的最低抑菌浓度(ＭＩＣ)范围相差仅2～4倍,而鸟分支杆菌野生株对上述药物的ＭＩＣ范围则…     

145株非结核分枝杆菌对10种药物的耐药性分析

目的了解我院非结核病患者分离的非结核分枝杆菌对10种药物的耐药状况。方法用MB/Bact 240分枝杆菌培养仪和改良罗氏管对患者的多种标本进行分枝杆菌分离培养鉴定,对分离到的分枝杆菌采用绝对浓度法对10种抗结核药物,利福平、异烟肼、乙胺丁醇、链霉素,利福喷丁、丙硫异烟肼、氧氟沙星、卷曲霉素、卡那霉素和对氨基水扬酸进行药物敏感性试验。结果 1722例患者的标本非结核分枝杆菌培养阳性145株,对10种药总耐药率97.2%（141/145）,单耐药率最高为异烟肼、链霉素和对氨基水扬酸,最低为氧氟沙星。结论非结核分枝杆菌耐药情况十分严重,应加强抗结核药物的耐药性监测;根据药敏试验选择科学有效的化疗方案。     

mRNA作为结核分支杆菌活菌检测标志的可行性研究

目的 探讨mRNA作为结核分支杆菌活菌检测标志的可行性。方法 采用定量聚合酶链反应(PCR)方法测定结核分支杆菌H37Rv在利福平、异烟肼、乙胺丁醇、链霉素、氧氟沙星处理后24、48、72h 85B mRNA表达水平的变化，并与活菌计数方法对比。结果 在异烟肼、利福平和链霉素处理24h时，结核分支杆菌H37Rv活菌数下降明显；在异烟肼、链霉素、乙胺丁醇及氧氟沙星各药各浓度处理72h时，活菌数相似，但利福平处理后活菌数较它们低。利福平处理24h后85B mRNA下降到无药对照的0．02％，其他药物处理分别下降到无药对照的1％～10％；各药处理72h后85B mRNA均下降到1％以下。结论 mRNA表达水平可以在短时间内反映出用药与无药的区别，并与菌落形成单位(cfu)几乎呈平行关系。mRNA是检测和判定结核分支杆菌“死”“活”的分子标志物。     

南京地区非结核分枝杆菌耐药性分析

目的 分析南京地区非结核分枝杆菌(NTM)近八年的感染情况及耐药趋势.方法 对南京胸科医院2002年～2010年实验室培养阳性的7412例菌株,经菌型鉴定为非结核分枝杆菌的333例菌株的药敏结果进行统计分析.结果 NTM对于常用的抗结核药物大多显现为高度耐药,特别是异烟肼、利福平、链霉素,只有乙胺丁醇、阿米卡星的耐药率稍低.结论 尽快规范非结核分枝杆菌的治疗方案,避免更多的药物出现耐药.     

晚期HIV感染者抗多种药物结核分支杆菌的外源性再感染

美国最近爆发了抗多种药物的结核病,主要累及HIV 感染者.为制订合理的防治方案,收集了纽约市1987年4月～1991年7月所见17例结核分支杆菌培养反复阳性患者的临床资料,对连续分离的结核分支杆菌作了限制性片段长度多形态(RFLP)分析.确定分离菌对异烟肼、利福平、链霉素和乙胺丁醇、毗嗪酰胺(1990年10月后的标本)的敏感性.培养     

山东省滨州市123例肺结核患者痰结核菌耐药情况分析

目的探讨肺结核患者痰结核菌的耐药情况。方法采用痰结核分支杆菌培养并做药物敏感性试验检测。结果肺结核患者耐药率为58.54%;耐异烟肼（INH,H）37.4%、利福平（RFP,R）13.8%、链霉素（SM,S）56.1%、乙胺丁醇（EMB,E）2.4%。至少耐异烟肼和利福平两种药的比例为16.26%。结论肺结核耐药情况严重,尤其是耐多药比例偏高,应引起足够重视。     

Bactericidal activity of streptomycin, isoniazid, rifampin, ethambutol, and pyrazinamide alone and in combination against Mycobacterium Tuberculosis.

Log-phase cultures of Mycobacterium tuberculosis in Tween-albumin medium were exposed to streptomycin, isoniazid, rifampin, ethambutol, and pyrazinamide in concentrations in the range likely to be present in serum during treatment of patients. The bactericidal activity of the drugs was measured as the decrease in viable counts at 4 and 7 days. The activity of single drugs was highest for streptomycin and next highest for rifampin and isoniazid, but ethambutol only started to kill after 4 days. When exposed to 2 drugs, bactericidal synergism was found with streptomycin/isoniazid and isoniazid/ethambutol; additivity, with streptomycin/rifampin; indifference, with isoniazid rifampin and streptomycin/ethambutol; and antagonism, with rifampin/ethambutol and isoniazid/pyrazinamide. When cultures were exposed to the 3 drugs, isoniazid, rifampin, and ethambutol, marked antagonism was found between isoniazid and rifampin, whereas the addition of isoniazid or an increase in its concentration increased the bactericidal activity.     

Antimicrobial activity of antituberculosis agents against anaerobic bacteria.

Anaerobic infections may coexist with tuberculosis, and can be mistaken for one another. The effect of therapy with antituberculosis chemotherapeutic agents against anaerobic bacteria (with the exception of rifampin) is unknown. We therefore examined the in vitro efficacy of certain commonly used antituberculosis agents (rifampin, isoniazid, and ethambutol) against 370 strains of anaerobic bacteria, including 86 isolates of Bacteroides fragilis. Rifampin at a concentration of 2 microgram/ml inhibited 91 percent of all anaerobic isolates. Both ethambutol and isoniazid were totally ineffective against any of the anaerobes tested, even at 64 microgram/ml. Therapy with rifampin in an unsuspected anaerobic infection can be misdiagnosed for tuberculosis. Therefore, when tuberculosis is suspected, isoniazid and ethambutol can be used and rifampin withheld until the acid-fast bacilli are demonstrated by additional diagnostic procedures, such as transtracheal aspiration.     

Evaluation of clinical efficacy of isoniazid and ethambutol in the treatment of nontuberculous mycobacteriosis based on in vitro susceptibility testing

Comparing minimal inhibitory concentrations (MICs) determined in various nontuberculous mycobacteria with those for Mycobacterium tuberculosis strains, which were isolated from patients who were untreated previously by any antituberculosis drugs, clinical efficacy of isoniazid and ethambutol in the treatment of nontuberculous mycobacteriosis was evaluated. The MICs of isoniazid for M. tuberculosis strains were 0.03-0.1 microgram/ml, whereas the MICs for M. xenopi strains were 0.1-0.4 microgram/ml, those for M. szulgai 0.2-0.8, and those for M. kansasii 0.8-1.6 micrograms/ml. The fact that M. xenopi strains are susceptible to isoniazid was reported previously, and in this study, it was shown that M. szulgai and M. kansasii are also considerably susceptible to isoniazid. Isoniazid may be useful in the treatment of infection due to these mycobacteria. The MICs of ethambutol for M. tuberculosis strains ranged from 0.8 to 3.13 micrograms/ml. The percentages of strains of various mycobacteria, which are susceptible to 3.13 micrograms/ml ethambutol, were 100% in M. szulgai, 100% in M. nonchromogenicum, 90% in M. gordonae, 88% in M. marinum, 77% in M. kansasii, 46% in M. malmoense, and 30% in M. scrofulaceum. In contrast, the percentage in M. avium complex strains remained only 19%. It has been suggested that ethambutol is effective in the treatment of diseases caused by M. szulgai, M. marinum and M. kansasii.     

Outcome of multidrug-resistant tuberculosis in human immunodeficiency virus-infected patients.

Among 324 cases of culture-proven tuberculosis from 1988 to 1996 in a hospital in Milan, Italy, 90 (27.8%) were due to Mycobacterium tuberculosis strains resistant to isoniazid and rifampin. Sixty-one of 69 isolates tested had identical restriction fragment length polymorphism patterns. The prevalent strain tested susceptible only to ethionamide and was also resistant to ethambutol, streptomycin, cycloserine, amikacin, kanamycin, terizodone, ofloxacin, rifabutin, rifapentin, and KRM 1648. The median survival time was 94 days. Multivariate analysis showed a trend toward better outcome in the period 1994-1996 (hazard ratio, 4.16; P<.001), and extrapulmonary localization of tuberculosis was the only other independent predictor of a negative outcome (hazard ratio, 2.1; P = .019). The delay from symptoms to beginning of therapy did not seem to be a determining factor in survival time. Standard antituberculosis therapy with four drugs (isoniazid, rifampin, ethambutol, and pyrazinamide) had a higher efficacy than did other regimens with fewer drugs but without a statistically significant difference.     

Determination of minimal inhibitory concentrations of antituberculosis drugs by radiometric and conventional methods

Minimal inhibitory Concentrations (MIC) of 5 antituberculosis drugs (isoniazid, rifampin, streptomycin, ethionamide, and ethambutol) were determined by the radiometric (BACTEC) broth method and by the agar plate proportion method. Seventeen M. tuberculosis strains, isolated from patients before treatment, were tested. The MIC values of 4 of the 5 drugs (the exception was streptomycin) were 2 to 4 times lower in 7H12 broth than in 7H11 agar. The broth-determined MIC were also at least 2 to 4 times lower than the achievable serum concentrations. The broth-determined MIC are probably much closer to the true MIC values than those determined in agar plates because of the lower degree of absorption and degradation in the liquid medium. The radiometric broth method is a simple and rapid quantitative method for accurate determination of the MIC values of the antituberculosis drugs. The data obtained in this study will be used for further evaluation of the MIC values as complementary or alternative to the conventional qualitative testing against critical concentrations.     

Tuberculosis in Korea. The relationship between prior therapy and drug resistance

A review of 121 culture-positive cases of pulmonary tuberculosis from 1979 to 1984, including both Korean and American patients, at the major US military hospital in Korea indicated that most antituberculosis drug resistance occurred in patients with a history of previous antituberculosis therapy. The 98 patients without previous therapy who were not household contacts of a known resistant case had low rates of drug resistance (7 percent to isoniazid, 5 percent to streptomycin, 2 percent to p-aminosalicylic acid, and none to rifampin or ethambutol). All were sensitive to at least two of the drugs in the commonly prescribed regimen of isoniazid, rifampin, and ethambutol. In contrast, both patients who were household contacts of a known resistant case and 11 (52 percent) of the 21 patients with previous therapy had drug-resistant organisms. Our data support the use of isoniazid as preventive therapy for those who develop tuberculin reactivity while in Korea, in the absence of close contact with a known resistant case. Our data also suggest that the regimen of isoniazid, rifampin, and ethambutol is appropriate initial therapy for active disease acquired in Korea, provided that an adequate history excluding these risk factors can be obtained.     

Current tuberculosis treatment regimens. Choosing the right one for your patient

This article has reviewed the use and adverse effects of available first-line and second-line antituberculosis drugs. Treatment regimens consisting of combinations of isoniazid, rifampin, pyrazinamide, streptomycin, and ethambutol will be sufficient in the majority of patients with tuberculosis. The rationale for use of short-course chemotherapy for tuberculosis is based on extensive worldwide experience. The clinical trials that provide the evidence to support the use of ATS/CDC-recommended 6- and 9-month chemotherapeutic regimens have been summarized with attention to the reported relapse rates. Alternative regimens are acceptable in patients who have adverse reactions or resistance to isoniazid and rifampin. Management of patients after starting chemotherapy for tuberculosis requires monitoring for adverse effects, ensuring adherence to therapy and evaluation of response to chemotherapy by documenting bacteriologic conversion. Extrapulmonary tuberculosis responds to the same chemotherapy regimens recommended for pulmonary disease, and corticosteroids are indicated in some forms.     

Increasing drug resistance of Mycobacterium tuberculosis isolates in Ontario, Canada, 1987-1998.

We examined trends in resistance to first-line antituberculous agents for Mycobacterium tuberculosis strains isolated in Ontario, Canada from 1987 through 1998 (n=8069). The proportions resistant were as follows: isoniazid, 9.6%; rifampin, 1.9%; streptomycin, 4. 9%; ethambutol, 1.3%; and pyrazinamide, 1.7%. Resistance to isoniazid has increased markedly since 1990, whereas resistance to streptomycin, ethambutol, and pyrazinamide increased from 1997 through 1998. Resistance to both isoniazid and rifampin did not increase. The incidence of persistence and reactivation (early or late treatment failure) was 1-2 per 100 person-years (PY) in the first 7-12 months and 0.3-0.9 per 100 PY from 13 months to 5 years thereafter. For initially susceptible strains, the incidence of resistance to isoniazid was 0.11 per 100 PY and for and rifampin was 0.06 per 100 PY in the first year and negligible thereafter, with an overall risk of 0.14% for isoniazid and 0.10% for rifampin. Resistance of M. tuberculosis to antituberculous agents, and in particular to isoniazid, is a growing problem in Ontario and is higher than elsewhere in Canada.     

The treatment of pulmonary tuberculosis. Current options

Appropriate chemotherapy must be received by the patient if the treatment of pulmonary tuberculosis is to be successful. The choice of the antituberculous regimen depends on the susceptibility and number of organisms infecting the patient and the side effects and cost of the drugs. The patient's life-style and the resources available in the community need to be considered to ensure compliance with the prescribed chemotherapy. If treatment is to be unsupervised, meaning that each dose is not actually witnessed by a health provider, a daily isoniazid and ethambutol hydrochloride treatment for 18 months or daily isoniazid and rifampin treatment for nine months is suggested. If each dose of chemotherapy is to be directly supervised, necessary for the noncompliant patient, then the following regimens are recommended: intermittent isoniazid and ethambutol, isoniazid and streptomycin, or intermittent isoniazid and rifampin following an initial period of daily therapy.     

Antituberculosis drug resistance in south Texas

The incidence of antituberculosis drug resistance in South Texas has been tabulated. Age, sex, and ethnic group were not found to significantly influence the incidence of resistance. The incidence of resistance to isoniazid (NH) was 16.4%, ethambutol, 3.9%, rifampin, 10.6%, and streptomycin, 7.8%. There was a 7.3% rate of resistance to INH and/or ethambutol or rifampin for any individual organism (i.e., to 2 of the 3 most commonly used antituberculosis drugs). We conclude that the incidence of single and multiple antituberculosis drug resistance in South Texas is higher than previously reported.