Pulmonary disease empirically treated as tuberculosis-a retrospective study of 107 cases

Pulmonary disease is sometimes treated empirically as tuberculosis (TB) in the absence of microbial confirmation if the clinical suspicion of active TB is high. In a country of relatively high TB and low HIV burden, we retrospectively studied 107 patients (69.2% male; mean age (SD): 45 (17) years) who received empirical anti-TB treatment for intrapulmonary opacities or pleural effusions suspected of active TB in our hospitals between 1998 and 2002. The diagnosis of definite or probable 'smear-negative' pulmonary TB was made based on treatment outcome at two months with rifampicin, isoniazid, pyrazinamide and ethambutol (or streptomycin). At this end-point, 81 patients (84.4%) had both clinical and radiological improvement (definite cases), 12 (12.5%) had clinical improvement alone and 3 (3.1%) had radiological improvement alone (probable cases). Confirmation of acid-fast bacilli was subsequently obtained in 12 patients (all definite cases) from culture of initial pulmonary specimens. Eleven patients (10.5%) were diagnosed as 'non-TB' based on absence of both clinical and radiological improvement or discovery of another cause for the pulmonary condition at or before this two-month study end-point. In the 'non-TB' group, 2 had carcinoma, 2 had HIV-related pulmonary diseases, 1 had bronchiectasis, while in 6 causes were indeterminate. Six (6.3%) and 3 (27.3%) patients reported adverse effects from anti-TB drugs from the 'TB' and 'non-TB' groups respectively. Our findings suggest that empirical anti-TB treatment is an acceptable practice if clinical suspicion is high in patients coming in our region.     

HIV/AIDS合并结核病患者196株结核分枝杆菌耐药分析

目的 探讨人类免疫缺陷病毒(HIV)/获得性免疫缺陷综合征(AIDS)合并结核病患者结核分枝杆菌菌株的耐药情况.方法 收集成都市公共卫生临床医疗中心2012年1月至2015年12月住院治疗的HIV/AIDS合并结核病初治患者196例,分析AIDS合并活动性结核病(包括肺结核及肺外结核)患者的痰液/组织液/纤冲液及病理组织送检分枝杆菌培养出的结核分枝杆菌菌株的耐药情况,采用BACTEC MGIT960鉴定系统进行菌型鉴定,960分枝杆菌培养系统进行药敏实验.结果 共培养出结核分枝杆菌菌株196株,发生结核分枝杆菌总体耐药率为26.02％;将196例AIDS合并结核病患者按CD4+T淋巴细胞计数不同分为大于100个/μL、≤100个/μL两组,比较两组患者结核分枝杆菌菌株对4种一线抗结核药物的耐药状况,发现两组患者结核分枝杆菌菌株对一线抗结核药物耐药率比较,差异无统计学意义(P＞0.05),一线抗结核药耐药发生率由高到低依次为:异烟肼、利福平、链霉素、乙胺丁醇.两组患者结核分枝杆菌菌株对5类耐药结核耐药率比较,差异无统计学意义(P＞0.05).结论 AIDS合并结核病初始患者耐药率与我国结核平均初始耐药水平一致,HIV/AIDS合并结核病患者的结核耐药性与CD4+T淋巴细胞计数水平高低无相关性.     

Ofloxacin in multidrug resistant tuberculosis

Tuberculosis (TB) is the leading infectious cause of death today and 3.81 million cases occurred in 1997 and 1998. Even today in spite of having four drugs like isoniazid, rifampicin, streptomycin/pyrazinamide and ethambutol for the intensive phase, the total duration of treatment remains six months. Because of the global health problems of TB, the increasing rate of multidrug resistant TB (MDR-TB) and the high rate of co-infection with HIV, the need for effective non-toxic antituberculous agents is essential. Fluoroquinolones have been classified as drugs having low bactericidal activity by the WHO. To date, they have been used for preventive therapy, empirical treatment of patients with TB and retreatment of patients with relapsing TB. In-vitro and in-vivo clinical studies have identified ofloxacin as a promising new agent in the treatment of MDR-TB. Ofloxacin has been advocated by the WHO in case of MDR-TB, when susceptibility to test results are not available before starting the new treatment, in the continuation period (18 months) and if resistance is proven to at least isoniazid and rifampicin.     

应用噬菌体生物扩增法对HIV/TB双重感染患者抗结核药耐药性分析研究

目的 利用噬菌体生物扩增法(PhaB)分析人类免疫缺陷病毒(HIV)合并结核病(TB)双重感染患者的结核分枝杆菌的耐药状况,优化防治对策.方法 运用PhaB法对重庆市第九人民医院收治的112例HIV/TB双重感染患者(HIV/TB组)做TB菌的药敏检测,并与208例单纯肺结核患者(单纯TB组)的药敏检测做对比分析.结果 HIV/TB组的抗TB药耐药率要比单纯TB组低,HIV/TB双重感染患者5种常见抗TB药物的耐药率分别为异烟肼(INH) 7.14％、吡嗪酰胺(PZA) 7.14％、利福平(RFP) 5.36％、链霉素(SM) 5.36％、乙胺丁醇(EMB)4.46％,与单纯TB组患者比较(RFP 17.31％、INH 13.46％、PZA11.54％、EMB 10.58％、SM 9.62％),HIV/TB组RFP的耐药率低于单纯TB组,差异有统计学意义(P＜0.05),其他4种抗TB药耐药率与单纯TB组比较差异无统计学意义(P＞0.05),与绝对浓度法结果符合率分别为INH 96.4％、RFP 98.2％、PZA 96.4％、EMB 93.8％和SM 96.4％.结论 本地区HIV/TB双重感染患者结核分枝杆菌对RFP耐药率较普通肺结核患者低,与该类患者良好的服药依从性相关.PhaB测定所需时间短,操作简便,不需特殊仪器设备,可作为结核分枝杆菌耐药性的快速筛选方法.     

74例结核分枝杆菌耐药情况分析

目的了解遵义地区结核分枝杆菌耐药情况,并探讨其耐药特点,为耐药结核病的监测提供参考。方法采用比例法对我院门诊及住院的肺结核患者痰标本中分离到的74株结核分枝杆菌进行异烟肼、利福平、链霉素和乙胺丁醇4种一线抗结核药物的敏感性试验。结果 74例肺结核患者结核分枝杆菌对一线抗结核药的总耐药率为54.1%,耐多药率为12.2%。结论本地区结核分枝杆菌耐药情况严重,应进一步加强耐药结核的监测。     

Drug procurement and management

A strong drug procurement and management system under the RNTCP is critical to programme success. Significant improvements in manufacturing, inspection, supply, storage and quality control practices and procedures have been achieved due to an intensive RNTCP network. Drugs used in RNTCP are rifampicin, isoniazid, ethambutol, pyrazinamide and streptomycin. Patients of TB are categorised into I, II and III and each category has a different standarised treatment. Procurement, distribution system and quality assurance of drugs are narrated in brief in this article.     

结核病人临床单耐药及风险因素回归分析

目的分析近年结核病单耐药趋势及其风险因素,为临床医务工作者早期发现耐药结核病提供参考依据。方法收集2015-2017年就诊于阜阳市传染病医院并接受住院治疗的肺结核病人的相关资料,对其四种一线抗结核药的单耐药率趋势进行分析,进一步探究单耐药相关临床特征及风险因素。结果一线抗结核药物异烟肼、利福平、乙胺丁醇和链霉素的耐药率3年均未发现上升或下降的变化趋势（P>0.05）。来源地农村、有结核接触病史、CT示肺部有空洞、双肺受累、合并有慢性阻塞性肺疾病和长期使用激素能够增加肺结核病人耐药发生的风险（P < 0.05~P < 0.01）。结论对农民、有结核接触病史、CT示有空洞、双肺受累、合并有慢性阻塞性肺疾病和长期使用激素者,需要及时做耐药检测,以对单耐药结核病人采取针对性的治疗。     

安徽省结核病结核杆菌耐药状况的调查

目的为了解安徽省新发涂阳肺结核病人的耐药状况。方法随机选择安徽皖南、皖中和皖北的6个县结核病项目门诊,收集项目门诊的初治涂阳病人的结核杆菌;采用WHO／IUATLD推荐的比例法,对异烟肼（H）、链霉素（S）、利福平（R）、乙胺丁醇（E）等4种抗结核药敏试验。结果449株结核分枝杆菌中对4种抗结核药物全部敏感者248例,占55．23％;201例耐药,总原发耐药率为44．77％,以耐S为最高,占31．4％。结论安徽省结核病耐药水平是较严重省份,对结核病控制工作将是一个大的挑战,耐药结核杆菌的控制将是下一步结核病控制重点之一。     

Study on hepatotoxicity and other side-effects of antituberculosis drugs

A prospective study of different side-effects and toxicity of different antituberculosis drugs was made on 125 cases of pulmonary tuberculosis, divided into 3 groups according to the regime of treatment. Group A consisted of 50 patients, taking streptomycin, ethambutol and isoniazid. Group B of 50 patients received streptomycin plus ethambutol plus isoniazid and rifampicin and 25 patients comprising group C received streptomycin plus isoniazid plus ethambutol and pyrazinamide. The group B showed hepatotoxicity in 30% cases, out of which clinical jaundice with abnormal liver function tests being 26% and rest 4% cases were of anicteric hepatitis, while group A showed only 6% hepatotoxicity with 4% clinical jaundice and 2% anicteric hepatitis. In group A out of 50 cases only 2 patients complained of colour blindness, which reversed with the stoppage of drugs. In group C out of 25 cases 3 patients had gouty problems and responded with stoppage of drugs. Patients in group A developed jaundice in a mean of 50 days while those in group B developed jaundice in 17 days.     

艾滋病合并结核病患者抗结核药物血药浓度的研究

目的：比较艾滋病合并结核病人同单纯结核病人抗结核药物血药浓度是否存在差异;比较艾滋病合并结核病病人CD4＋T淋巴细胞水平与抗结核药物血药浓度是否存在相关性。方法：高效液相色谱法测定28例艾滋病合并结核病患者及28例单纯结核病人血清中利福平,异烟肼及吡嗪酰胺血药浓度,比较两组病人抗结核药物血药浓度是否存在差异。用流式细胞仪测定艾滋病合并结核病病人CD4＋T淋巴细胞水平,比较其与抗结核药物血药浓度是否存在相关性。结果：艾滋病合并结核病组病人利福平血药浓度低于单纯结核病人（t=-6.563,P=0.000）。两组病人异烟肼血药浓度对比无统计学差异（t=-0.675,P=0.506）。两组病人吡嗪酰胺血药浓度对比无统计学差异（t=0.063,P=0.951）。CD4＋T淋巴细胞水平与血清中利福平浓度无相关性（r=0.38,P=0.099）,CD4＋T淋巴细胞水平与血清中异烟肼浓度无相关性（r=0.081,P=0.681）,CD4＋T淋巴细胞水平与血清中吡嗪酰胺浓度无相关性（r=0.125,P=0.527）。结论：艾滋病合并结核病病人利福平血药浓度低于单纯结核病人。两组病人异烟肼及吡嗪酰胺血药浓度无差异。CD4＋T淋巴细胞水平与血清中利福平,异烟肼,吡嗪酰胺血药浓度无相关性。     

结核菌罗氏培养基药敏试验结果判读时间分析

目的 分析结核菌罗氏培养基药敏试验结果的合理判读时间,从而使药敏实验的准确性得到提高。方法 选择2013年4月—2016年12月期间淮安市疾病预防控制中心收治的2 371例肺结核患者作为研究对象,其中新涂阳初治患者2 136例,复治涂阳患者235例。患者痰标本均在实验室质控下完成检测,作为标准结果,同时在本院进行罗氏培养基药敏试验,分别培养4周和6周后,将检测结果与标准结果进行对比分析,分别统计比对培养4周和6周的结果准确率。结果 初治患者培养4周药敏试验结果准确率异烟肼（98.60%）、链霉素（95.22%）、利副平（96.54%）、乙胺丁醇（95.88%）与培养6周准确率（94.48%、96.54%、97.94%、97.24%）比较,差异均有统计学意义（P<0.05）。 复治患者培养4周异烟肼药敏试验准确率（98.30%）与培养6周准确率（93.62%）比较差异具有统计学意义（P<0.05）;培养4周链霉素（94.89%）、利副平（96.60%）、乙胺丁醇（96.32%）药敏试验准确率与培养6周准确率（95.74%、97.87%、97.02%）比较,差异均无统计学意义（P>0.05）。初治和复治患者：4周和6周的准确率比较差异无统计学意义。结论 结核菌罗氏培养基药敏试验结果准确性与判读时间存在一定联系,应根据具体药物选择具体时间。     

邯郸市2013年初、复治涂阳肺结核患者耐药状况分析

目的分析邯郸市初、复治肺结核患者耐药状况,为结核病的临床和控制提供参考依据。方法对邯郸市2013年间登记的348例涂阳肺结核患者痰标本经培养阳性并作菌株鉴定。用比例法对结核分枝杆菌进行抗异烟肼(H)、利福平(R)、链霉素(S)和乙胺丁醇(E)的耐药性检测,并分析结核分枝杆菌的耐药状况。结果 348例结核分枝杆菌感染的涂阳肺结核患者中,总耐药率30.75%,耐多药率14.37%。复治组耐药率及耐多药率均高于初治组,差异有统计学意义(χ2=67.41,χ2=52.11,P0.01)。对4种抗结核药物的耐药频度由高到低依次为H(42.53%)、S(34.20%)、R(27.59%)、E(20.98%)。初治组对4种抗结核药物的耐药率较复治组低,差异均有统计学意义(P0.01)。结论邯郸市肺结核患者结核分枝杆菌耐药发生率高,需进一步加强耐药结核病的检测和防控。     

抗结核同时给予阿德福韦酯治疗慢性乙型肝炎合并肺结核的临床疗效

目的评价抗结核同时给予阿德福韦酯治疗慢性乙型肝炎合并肺结核的临床疗效。方法将2006年9月至2008年9月在我院接受抗结核药物治疗的慢性乙型肝炎患者94例,按照肺部结核病灶情况、肝功能损害程度和乙肝病毒定量指标,以同等病情匹配的原则分为治疗组和对照组,治疗组47例,应用异烟肼、利福喷汀、吡嗪酰胺、链霉素或乙胺丁醇及常规保肝药物,同时给予阿德福韦酯10mg口服,每日1次,疗程8个月。对照组47例应用与治疗组同样的抗结核及保肝药物,治疗8个月。评价治疗前后患者临床症状、肝功能、HBVDNA水平、痰菌转阴及肺部病灶吸收情况,采用U和x。检验对数据做统计学处理。结果治疗后治疗组肝损伤加重者3例（占6．4％）,对照组18例（占47．3％）,两者差异有统计学意义;治疗后治疗组临床症状出现率、HBVDNA转阴率、HBVDNA下降率、痰菌转阴率及肺部病灶吸收率均明显好于对照组,分别为6．4％与47．3％、51．1％与0．0％、48．9％与2．6％、87．2％与39．5％及95．7％与50．0％（P〈0．05）。治疗前后两组肾功能检测均正常,治疗过程中或治疗结束时未发现HBV变异耐药病例。未发现使用阿德福韦酯有明显不良反应。结论阿德福韦酯可以减少慢性乙型肝炎合并肺结核患者应用抗结核药物引起的肝损伤,安全性良好。     

重庆市638例肺结核患者耐药流行现状分析

目的了解重庆市638例肺结核患者耐药流行现状与流行特点,为下一步耐药肺结核病防控提供依据。方法对2015年重庆市结核病参比实验室收集的638例涂阳肺结核痰培养标本进行异烟肼、利福平、乙胺丁醇、链霉素、氧氟沙星和卡那霉素等6种抗结核药物敏感试验检测,对其结果进行分析。结果 638例涂阳肺结核患者总耐药为35.6%,耐多药率为23.8%,复治涂阳肺结核患者的总耐药率和耐多药率(44.3%和28.8%)均高于初治涂阳肺结核患者(16.1%和8.7%,P0.05);5类高危人群的总耐药率和耐多药率均高于新患者(P0.05)。女性肺结核患者的总耐药率和耐多药率高于男性患者(P0.05);不同年龄组、地区的总耐药率和耐多药率差异有统计学意义(P0.05);检测的6种抗结核病药物耐药顺位由高到低依次为利福平、异烟肼、链霉素、氧氟沙星、乙胺丁醇和卡那霉素,单耐药以利福平耐药为主(74.2%),多耐药以异烟肼和链霉素耐药为主(72.7%),耐多药中耐利福平和异烟肼占45.4%。结论重庆市耐药结核病高危人群和重点地区的耐药流行较为严重,应加强耐药结核病的发现和治疗管理工作;同时应加大防治经费投入,采取全面、积极的干预措施遏制耐药结核病的流行。     

荧光定量PCR在结核分枝杆菌耐药性检测中的应用价值

目的 探究和分析荧光定量PCR检测技术在结核分枝杆菌耐药性检测方面的价值。方法 随机选取苏州市第五人民医院门诊或者住院病人的痰培养阳性标本菌株,并提取核酸。应用荧光定量PCR扩增试剂盒对菌株标本的链霉素、利福平、异烟肼、乙胺丁醇、阿米卡星以及莫西沙星的耐药情况进行检测分析,并将检测结果与传统的罗氏药敏比例法进行比对分析。结果 与罗氏药敏比例法相比较,荧光定量PCR检测法对链霉素、利福平、异烟肼、乙胺丁醇、阿米卡星以及莫西沙星的耐药检测符合率分别为90.48%、82.14%、83.33%、88.09%、89.29%、89.28%。Kappa检验结果显示,两种方法对链霉素的检测结果一致性较高,Kappa值为0.815;对利福平、异烟肼、乙胺丁醇、莫西沙星的检测结果一致性一般,Kappa值分别为0.637、0.631、0.623、0.578;对阿米卡星的检测结果一致性较差,Kappa值为0.279。结论 荧光定量PCR检测技术对于结核分枝杆菌耐药性的快速检测均有很好的应用价值,对于临床上的精准用药具有一定的指导意义。     

HBV、TB合并感染时抗TB治疗对肝功能的影响

目的:探讨乙型肝炎病毒(HBV)、结核(TB)杆菌合并感染时抗TB药物所致肝损伤的临床及组织学特点。方法:单纯TB感染者45例,TB合并HBV感染者35例,前4月均服用异烟肼、利福平、吡嗪酰胺、乙胺丁醇,后2月服用异烟肼、利福平。每2～4周复查肝功能、HBV标记物、T细胞亚群等指标,部分患者进行了肝穿刺病理检查。结果:TB HBV组肝功能异常发生率为34.3%,较单纯TB组高,发生时间较单纯TB组早半月,发生平均年龄小8岁;谷丙转氨酶水平、肝组织学炎症积分均较TB组高(P<0.05);肝功能异常者中80%为HBeAb阳性,T细胞免疫功能紊乱较重,CD4 细胞明显减少(P<0.05)。结论:HBV、TB合并感染时,抗TB药物的肝毒性增强,治疗过程中应及时复查肝功能。     

Determination of drug susceptibility and DNA fingerprint patterns of clinical isolates of Mycobacterium tuberculosis from Kampala, Uganda

This study was undertaken to determine the rate of initial drug resistance and transmission patterns of Mycobacterium tuberculosis (TB) in Kampala, Uganda. Using a radiometric BACTEC 460 TB system, 215 M. tuberculosis isolates from previously untreated patients (aged 17-48 years, mean age = 28 years; 56% males and 69% HIV-seropositive) were analyzed for susceptibility to isoniazid, rifampin, streptomycin, and ethambutol. Isolates from 73 patients were examined for strain diversity or relatedness using the insertional sequence 6110 (IS6110) DNA fingerprinting technique. The study revealed the following drug resistance rates: isoniazid, 7.9%; streptomycin, 6.1%; rifampin, 1.4%; and ethambutol, 0.9%. Resistance to at least one of the first line drugs tested were developed by 12% of the strains, while 4.7% showed multiple resistance. However, no significant differences in resistance rates were found between patients with and without HIV infection. Using the number and size of DNA fragments containing IS6110, only three clusters of isolates with identical patterns were found out of the 73 isolates tested (8.2%). Each cluster contained two isolates, and three isolates had less than 7 copies of IS6110. These findings suggest that initial drug resistance to anti-tuberculosis agents in this region is low and similar to other countries in sub-Saharan Africa and that multiple strains of M. tuberculosis have been transmitted within the community.     

Standard short-course chemotherapy for drug-resistant tuberculosis: treatment outcomes in 6 countries

CONTEXT: No large-scale study has investigated the impact of multidrug-resistant tuberculosis (TB) on the outcome of standard short-course chemotherapy under routine countrywide TB control program conditions in the World Health Organization's (WHO) directly observed treatment short-course strategy for TB control. OBJECTIVE: To assess the results of treatment with first-line drugs for patients enrolled in the WHO and the International Union Against Tuberculosis and Lung Disease's global project on drug-resistance surveillance. DESIGN AND SETTING: Retrospective cohort study of patients with TB in the Dominican Republic, Hong Kong Special Administrative Region (People's Republic of China), Italy, Ivanovo Oblast (Russian Federation), the Republic of Korea, and Peru. PATIENTS: New and retreatment TB cases who received short-course chemotherapy with isoniazid, rifampicin, pyrazinamide, and either ethambutol or streptomycin between 1994 and 1996. MAIN OUTCOME MEASURE: Treatment response according to WHO treatment outcome categories (cured; died; completed, defaulted, or failed treatment; or transferred). RESULTS: Of the 6402 culture-positive TB cases evaluated, 5526 (86%) were new cases and 876 (14%) were retreatment cases. A total of 1148 (20.8%) new cases and 390 (44.5%) retreatment cases were drug resistant, including 184 and 169 cases of multidrug-resistant TB, respectively. Of the new cases 4585 (83%) were treated successfully, 138 (2%) died, and 151 (3%) experienced short-course chemotherapy failure. Overall, treatment failure (relative risk [RR], 15.4; 95% confidence interval [CI], 10.6-22.4; P<.001) and mortality (RR, 3.73; 95% CI, 2.13-6.53; P<.001) were higher among new multidrug-resistant TB cases than among new susceptible cases. Even in settings using 100% direct observation, cases with multidrug resistance had a significantly higher failure rate than those who were susceptible (9/94 [10%] vs 8/1410 [0.7%]; RR, 16.9; 95% CI, 6.6-42.7; P<.001). Treatment failure was also higher among patients with any rifampicin resistance (n=115) other than multidrug resistance (RR, 5.48; 95% CI, 3.04-9.87; P<.001), any isoniazid resistance (n=457) other than multidrug resistance (RR, 3. 06; 95% CI, 1.85-5.05; P<.001), and among patients with TB resistant to rifampicin only (n=76) (RR, 5.47; 95% CI, 2.68-11.2; P<.001). Of the retreatment cases, 497 (57%) were treated successfully, 51 (6%) died, and 124 (14%) failed short-course chemotherapy treatment. Failure rates among retreatment cases were higher in those with multidrug-resistant TB, with any isoniazid resistance other than multidrug resistance, and in cases with TB resistant to isoniazid only. CONCLUSIONS: These data suggest that standard short-course chemotherapy, based on first-line drugs, is an inadequate treatment for some patients with drug-resistant TB. Although the directly observed treatment short-course strategy is the basis of good TB control, the strategy should be modified in some settings to identify drug-resistant cases sooner, and to make use of second-line drugs in appropriate treatment regimens. JAMA. 2000;283:2537-2545     

Risk factors and drug-resistance patterns among pulmonary tuberculosis patients in northern Karnataka region,India

Background:

India is one of the high tuberculosis (TB)-burden countries in the world. Resistance to anti-tuberculosis (anti-TB) drugs has already become an important and alarming threat in most of the regions worldwide. India ranks second in the world in harbouring multi-drug resistant cases (MDRTB). Prevalence of MDR-TB mirrors the functional state and efficacy of TB control programmes and realistic attitude of the community towards implementation of such programmes. The most important risk factor in the development of MDRTB is improper implementation in the guidelines in the management of TB, and high rate of defaults on the part of the patients. The study was carried out to evaluate the drug resistance pattern to first line anti-TB drugs in Northern Karnataka region, India.

Materials and Methods:

A prospective study was conducted at J. N. Medical College and its associated Hospitals, Belgaum. Between January 2011 and December 2012, 150 sputum samples of suspected pulmonary TB patients based on the history were examined for the AFB culture by Lowenstein-Jensen (LJ) culture technique. A total of two early morning samples were collected for the smear [Ziehl-Neelsen (ZN) staining] and culture methods. It was observed that ZN staining for AFB was positive in 113 patients (75%), while AFB culture by LJ medium yielded growth in 66 cases (44%). Thus, a total of 66 AFB culture-positive samples by LJ medium were subjected for AFB drug-sensitivity testing (DST). DST was done for Isoniazid (INH), Rifampicin (RIF), Pyrazinamide (PZA), Ethambutol (EMB) and Streptomycin (SM) after isolation by using the resistance proportion method.

Results:

A total of 66 AFB culture-positive specimens, 20 (30.3%) cases were sensitive to all the five drugs while 46 (69.7%) cases showed resistance to one or more drugs. Among these, the resistance to rifampicin was highest (80.4%), while resistance to isoniazid, pyrazinamide, ethambutol and streptomycin were observed to be 60%, 58.7%, 52.1% and 63%, respectively. It was also observed that, resistance to all five drugs was highest (39.18%). MDR isolates were obtained in 52.2% of the cases. Illiteracy, low socio-economic status, previous history of TB and alcoholism were found to have statistically significant association for the development of MDR.

Conclusions:

The prevalence of drug resistance in the present study was observed to be 69.7%. More than half of the cases were multi-drug resistant. The most common resistant pattern observed in this study was resistance to all the first-line drugs. Therefore, during initiation of new case proper explaining and completion of the treatment is very important to avoid the development of future drug resistance in the society.     

Mycobacteria: treatment approaches and mechanisms of resistance

First-line drugs for tuberculosis treatment include isoniazid, rifampin, ethambutol, streptomycin, and pyrazinamide. Molecular mechanisms for resistance to each of these drugs have been elucidated. In every case, resistance is conferred by mutations in existing genes, not by the acquisition of new genetic material. Drug resistance is a major problem worldwide, but the rates vary widely among countries and within countries. Acquired resistance in previously-treated patients is much more common than primary resistance in patients with no previous treatment. High rates of acquired resistance have been reported from referral centers in Saudi Arabia and Lebanon. Successful TB treatment requires prolonged therapy with at least two active drugs. Directly-observed therapy (DOT) improves success rates and reduces the risk of acquired resistance. TB due to susceptible strains can be cured in over 95% of cases.