吡嗪酰胺酶活性与耐多药肺结核近期临床疗效的相关性研究

目的 研究吡嗪酰胺酶活性与耐多药肺结核(multidrug-resistant pulmonary tuberculosis,MDR-PTB)近期疗效的相关性,为MDR-PTB患者化学药物治疗的选择提供指导。 方法 采用前瞻性队列研究的方法,将广州市胸科医院2018年7月至2019年12月收治的85例MDR-PTB患者作为研究对象,均接受世界卫生组织推荐的6Am-Mfx-PZA-Pto-Cs/18Mfx-PZA-Pto-Cs(Am:阿米卡星;Mfx:莫西沙星;PZA:吡嗪酰胺;Pto:丙硫异烟胺;Cs:环丝氨酸)治疗方案。85例患者中,剔除9例丢失、中断治疗、失访患者,共76例患者纳入最终研究。以Wayne方法检测吡嗪酰胺酶的活性,以BACTEC MGIT 960方法检测吡嗪酰胺药物敏感性;比较吡嗪酰胺酶阳性患者与阴性患者治疗2、4、6个月末痰菌阴转、病灶吸收和空洞闭合情况。 结果 76例患者中,吡嗪酰胺酶阳性32例(42.1%),吡嗪酰胺酶阴性44例(57.9%);吡嗪酰胺表型耐药36例(47.4%),吡嗪酰胺表型敏感40例(52.6%)。吡嗪酰胺药物敏感性检测与吡嗪酰胺酶活性检测的一致性较高(Kappa=0.687,P=0.000)。吡嗪酰胺酶阳性患者治疗4个月末病灶吸收率(59.4%,19/32)及空洞闭合有效率(65.5%,19/29)均高于吡嗪酰胺酶阴性患者[分别为36.4%(16/44)和36.8%(14/38)],差异均有统计学意义(χ²=3.949,P=0.047;χ²=5.411,P=0.020)。吡嗪酰胺酶阳性患者治疗6个月后的空洞闭合有效率(86.2%,25/29)高于吡嗪酰胺酶阴性患者(63.2%,24/38),差异有统计学意义(χ²=4.447,P=0.035)。 结论 MDR-PTB患者的疗效与吡嗪酰胺酶活性有关,吡嗪酰胺酶阳性患者应用含吡嗪酰胺的MDR-PTB标准方案治疗后,病灶吸收及空洞闭合的效果优于吡嗪酰胺酶阴性患者。     

Drugs with activity against Mycobacterium tuberculosis

Treatment for Mycobacterium tuberculosis has to be lengthy, since populations of this bacillus differ in metabolic activity, and it has to consist of various associated drugs, since spontaneous chromosome mutations can give rise to drug resistance. The multiresistant phenotype emerges with sequential acquisition of mutations in several loci of separate genes. Knowledge of the mechanisms of resistance permits the development of molecular techniques for the early detection of resistant strains, thereby making proper control possible. Tuberculosis treatment includes isoniazid, rifampicin and pyrazinamide during the first two months and isoniazid and rifampicin to complete six months of treatment. In specific situations, a fourth drug is added, ethambutol for adults and streptomycin for children in whom visual acuity cannot be monitored. This review describes the characteristics, activity, resistance mechanisms and side effects associated with the various antituberculosis drugs.     

氯法齐明与其他抗结核药物联用对结核分枝杆菌的作用

目的 研究氯法齐明与其他抗结核药物联合应用对MTB的抗菌活性,为临床合理应用提供依据.方法 应用微孔板指示剂法测定10种抗结核药物单独及与氯法齐明联合应用时MTB的最低抑菌浓度(MIC),计算其部分抑制浓度(FIC)并评价氯法齐明与其他抗结核药物之间是否存在协同作用.将90只BALB/C小鼠尾静脉注射感染耐药MTB临床株成为耐药结核病动物模型,分为空白对照组及13个治疗组,每组6只.单独应用氯法齐明、克拉霉素、莫西沙星、对氨基水杨酸钠(PAS)、乙胺丁醇、阿米卡星和卷曲霉素,并将氯法齐明与上述药物联合治疗小鼠,给药30 d后解剖各组小鼠,计数肺、脾活菌数.采用单因素方差分析,比较各组药物的抗结核活性.结果 氯法齐明与抗结核药物联合应用时,MIC降至应用单药的1/2～1/8,氯法齐明分别与PAS、丙硫异烟胺、克拉霉素和卷曲霉素联合应用时,FIC分别为0.31、O.185、0.31和0.28,具有协同作用.各治疗组小鼠的肺、脾活菌数均较空白对照组低,单药组中氯法齐明的作用最为明显,分别较空白对照组降低了1.82和2.32 lg CFU,氯法齐明与克拉霉素联合应用的抗结核作用较单独应用氯法齐明更强,且较单用克拉霉素组的抗菌活性增加,活菌数分别降低1.30和1.91lg CFU,提示联合应用可增强药物的抗结核作用.结论 体外及小鼠体内的实验结果均提示,氯法齐明与克拉霉素联合应用有协同抗结核作用.     

Bactericidal activity in vitro of various rifamycins against Mycobacterium avium and Mycobacterium tuberculosis

Minimal inhibitory and bactericidal concentrations (MICs and MBCs) of rifampin (RMP), rifabutin (RBT), rifapentine (RPT), CGP-7040, and P-DEA, were determined for 50 M. avium strains in 7H12 liquid medium radiometrically under various pH conditions. Half were isolated from patients with AIDS and the other half from patients without AIDS but with pulmonary disease. The MICs and MBCs were also determined in 7H12 broth for M. tuberculosis strains. The MIC results obtained with M. tuberculosis strains, and the serum peak levels in humans, were used as standards for interpretation of the MICs and MBCs of the rifamycins for M. avium. The bactericidal activity of all rifamycins for M. avium was substantially lower than for M. tuberculosis. The majority of M. avium strains was within the "susceptible" category, e.g., comparable to susceptible M. tuberculosis strains, when tested with CGP-7040 and RPT, and all of them were "moderately susceptible" when tested with P-DEA. On the basis of in vitro bacteriostatic and bactericidal activity, it seems that three agents, RPT, P-DEA, and CGP-7040 have more potential than do RMP and RBT against M. avium disease.     

重组结核分枝杆菌RpfE蛋白对BCG休眠菌的促生长作用

目的观察重组结核分枝杆菌RpfE蛋白对BCG的促生长作用。方法将测序正确的Rv2450c基因克隆到表达载体pET32a(+)中,获得RpfE蛋白,在变性条件下对目的蛋白进行亲和层析纯化。将纯化的蛋白分别与结核病人血清,Rpf单抗和Rpf结构域单抗进行Western blot分析。分别将10pmol/L和100pmol/L的RpfE加入到休眠BCG的培养基中,观察RpfE蛋白对BCG的促生长作用。结果得到融合组氨酸残基的重组RpfE蛋白,Western blot结果显示该蛋白分别与活动期结核病人血清,Rpf单抗和Rpf结构域单抗在40kDa处发生反应。100pmol/L的RpfE蛋白对BCG休眠菌具有明显的复苏和促生长作用。结论构建了MtbRv2450c基因的重组表达载体,纯化获得了RpfE重组蛋白,该蛋白对BCG休眠菌具有复苏和促生长作用。     

康乐霉素A体外抗结核活性的初步研究

目的发现新安莎类抗生素，康乐霉素A体外抗结核活性。方法应用色谱技术从地中海诺卡氏菌康乐变株1747-64发酵液中分离康乐霉素A，并采用试管二倍稀释法，进行康乐霉素A对耻垢分枝杆菌（ATCC14468），结核分枝杆菌H37Rv（ATCC27294），H37Ra（ATCC25177），临床分离的氧氟沙星（OFLX）敏感结核分枝杆菌以及临床分离的耐氧氟沙星结核分枝杆菌最低抑制浓度（Minimal Inhibitor Concentration，MIC）的试验。结果康乐霉素A对耻垢分枝杆菌活性弱，MIC为64μg／ml，对结核分枝杆菌H37Rv，H37Ra的MIC为8μg／ml，对临床分离的氧氟沙星敏感结核分枝杆菌菌株的MIC范围为1～8μg／ml，临床分离的耐氧氟沙星结核分枝杆菌菌株的MIC范围为1～16μg／ml。结论新安莎类抗生素，康乐霉素A体外具有明显的抗结核活性，有望成为新抗结核药物或先导化合物。     

康乐霉素A体外抗结核活性的初步研究

目的发现新安莎类抗生素,康乐霉素A体外抗结核活性。方法应用色谱技术从地中海诺卡氏菌康乐变株1747-64发酵液中分离康乐霉素A,并采用试管二倍稀释法,进行康乐霉素A对耻垢分枝杆菌（ATCC14468）,结核分枝杆菌H₃₇Rv（ATCC27294）,H₃₇Ra（ATCC25177）,临床分离的氧氟沙星（OFLX）敏感结核分枝杆菌以及临床分离的耐氧氟沙星结核分枝杆菌最低抑制浓度（Minimal Inhibitor Concentration,MIC）的试验。结果康乐霉素A对耻垢分枝杆菌活性弱,MIC为64μg/ml,对结核分枝杆菌H₃₇Rv,H₃₇Ra的MIC为8μg/ml,对临床分离的氧氟沙星敏感结核分枝杆菌菌株的MIC范围为18μg/ml,临床分离的耐氧氟沙星结核分枝杆菌菌株的MIC范围为116μg/ml。结论新安莎类抗生素,康乐霉素A体外具有明显的抗结核活性,有望成为新抗结核药物或先导化合物。     

Anti-mycobacterial activity of plumericin and isoplumericin against MDR Mycobacterium tuberculosis

Background and objectivesBecause of the developing resistance of Mycobacterium species against currently available anti-mycobacterial drugs, there is an urgent need for new drug development. In this study, we have evaluated the in vitro anti-mycobacterial activity of Plumeria bicolor extract and its phytoconstituents – plumericin and isoplumericin against multi-drug resistance Mycobacterium tuberculosis.MethodsThe in vitro anti-mycobacterial activity of chloroform extract of P. bicolor, plumericin and isoplumericin were tested against M. tuberculosis (H37Rv) and four multi-drug resistant (MDR) clinical isolates by measuring the minimum inhibitory concentration (MIC) using MTT (Tetrazolium bromide [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide]) assay. The extract and both compounds were further evaluated by standard assay procedures to determine their minimum bactericidal concentration (MBC). Cytotoxicity of these compounds was performed against J774G8 murine macrophage cell lines. The activity was represented in the mean (±SD) of duplicate samples from three independent assays.ResultsPlumericin showed better activity against pan sensitive as well as four MDR strains of M. tuberculosis with MIC values of 2.1 ± 0.12, 1.3 ± 0.15, 2.0 ± 0.07, 1.5 ± 0.13 & 2.0 ± 0.14 μg/mL and MBC values of 3.6 ± 0.22, 2.5 ± 0.18, 3.8 ± 0.27, 2.9 ± 0.20 & 3.7 ± 0.32 μg/mL than isoplumericin, respectively. Interestingly, both isolated active compounds showed an advantage over rifampicin (80 times) and isoniazid (8 times) by being highly active against the MDR strains. The extract and both compounds were found to be non-toxic against J774G8 macrophages up to the used concentrations.ConclusionPlumericin showed more potent activity than isoplumericin. The excellent activity of these compounds against MDR strains opens a possibility of obtaining new anti-mycobacterial drug candidate in near future.