以棋盘法测定汉防己甲素与伊曲康唑的体外联合抗烟曲霉作用

目的 探讨汉防己甲素在体外对伊曲康唑抗烟曲霉活性是否有增效作用。方法 参照美国临床和实验室标准协会（CLSI）推荐的M38-A2方案,采用棋盘式微量液基稀释法,以21株烟曲霉临床株为研究对象,测定汉防己甲素联合伊曲康唑对其的抗真菌活性,以OD值测定法判读最低抑菌浓度,并以FICI法评价结果,同时以其中的AF46株为代表,用等效线图解法验证结果。结果 汉防己甲素与伊曲康唑单独作用于上述烟曲霉临床株的最低抑菌浓度值分别为256~512 μg/mL、0.125~32 μg/mL,联合用药时的最低抑菌浓度值分别降至8~64 μg/mL、0.03~2 μg/mL,且终点清晰,“拖尾现象”消失,FICI值为0.08~0.38,均表现为显著协同作用。AF46株的等效曲线呈凹形,也表明具有协同作用。结论 汉防己甲素在体外对伊曲康唑抗烟曲霉活性有显著增效作用。     

汉防己甲素对氟康唑抗白念珠菌菌丝相活性的增效作用及其机制研究

目的探讨体外汉防己甲素对氟康唑抗白念珠菌菌丝相活性是否有增效作用及其机制。方法参照微量稀释法确定汉防己甲素对白念珠菌菌丝相的非细胞毒性剂量,并测定氟康唑单独及联合汉防己甲素时对16株同一亲本白念珠菌菌丝相的MIC。荧光分光光度计测定加入及未加入汉防己甲素时此系细胞内罗丹明123的荧光强度。结果在终质量浓度≤2μg/mL汉防己甲素的作用下,白念珠菌菌丝相的存活率>95%;氟康唑单独作用时,对16株白念珠菌菌丝相的MIC值为0.250～64μg/mL;与汉防己甲素(2μg/mL)联合时,氟康唑对受试菌的MIC值降至0.125～8μg/mL,且终点清晰,"拖尾现象"消失。蓄积实验后,加入与未加入汉防己甲素的此系细胞内罗丹明123荧光强度分别为2.499～50.428、2.849～26.035(P=0.025);外排实验后,该值分别为1.006～7.267、0.191～6.685(P=0.000)。结论汉防己甲素在体外对氟康唑抗白念珠菌菌丝相活性有增效作用;汉防己甲素可抑制白念珠菌菌丝相药物外排泵的功能。     

汉防己甲素对氟康唑抗白念珠菌生物膜增效活性的初步研究

目的探讨汉防己甲素（tetrandrine,TET）对氟康唑（fluconazole,FLC）抗白念珠菌生物膜是否有增效活性。方法构建白念珠菌生物膜,参照微量稀释法,测定FLC单独及其联合TET对生物膜不同时期的最小抑菌浓度（minimum in-hibitory concentration,MIC）;生物膜重新悬浮后,测定FLC单独及其联合TET对不同浓度菌液的MIC。结果 FLC单独及其联合TET对白念珠菌生物膜最初期（0h）的MIC50值范围分别为0.25～64μg/mL和0.125～16μg/mL（P=0.002）;早期（4h）的MIC50值范围分别为8～256μg/mL和1～64μg/mL（P=0.000）;中期（24h）、成熟期（48h）的MIC50值均〉1024μg/mL。生物膜重新悬浮后,FLC单独及其联合TET对低浓度菌液（终浓度为1×103 CFU/mL）的MIC值范围分别为0.25～64μg/mL和0.125～16μg/mL（P=0.003）,高浓度菌液（终浓度为1×106 CFU/mL）的MIC值均〉64μg/mL。结论汉防己甲素在体外对氟康唑抗白念珠菌生物膜最初期（0h）、早期（4h）有增效活性,对中期（24h）、成熟期（48h）无增效活性;汉防己甲素对氟康唑抗白念珠菌生物膜重新悬浮后的低浓度菌液（终浓度为1×103 CFU/mL）有增效活性,高浓度菌液（终浓度为1×106 CFU/mL）无增效活性。     

汉防己甲素对伊曲康唑、伏立康唑和泊沙康唑抗烟曲霉体外增效活性研究

目的 探讨汉防己甲素(tetrandrine,TET)对伊曲康唑(itraconazole,ITR)、伏立康唑(voriconazole,VRC)和泊沙康唑(posaconazole,PCZ)体外 抗烟曲霉有无增效活性。方法 参照M38-A2方案的微量稀释法,以23株烟曲霉临床株为研究对象,测定TET对其的最大非细胞毒性剂量和ITC、VRC、PCZ单独及联合TET对其的最小抑菌浓度(minimal inhibitory concentrations,MICs)。结果 TET抗烟曲霉的最大非细胞毒性剂量为 80 μg/mL。 ITC单独及联合TET对烟曲霉的MIC值范围分别为0.5 μg/mL~32 μg/mL 和0.0625 μg/mL~4 μg/mL,差异有统计学意义(P<0.05) ;VRC单独及联合TET 的MIC值范围分别为0.25 μg/mL~2 μg/mL 和0.03125 μg/mL~0.25 μg/mL,差异有统计学意义(P<0.05); PCZ单独及联合TET 的MIC值范围分别为0.125 μg/mL~1 μg/mL 和0.03125 μg/mL~0.25 μg/mL,差异有统计学意义(P<0.05) 。结论 汉防己甲素在体外对伊曲康唑、伏立康唑和泊沙康唑 抗烟曲霉有增效活性。     

汉防己甲素体外抗泡球蚴作用的研究

目的　比较汉防己甲素、阿苯哒唑和汉防己甲素脂质体体外抑制原头节作用 ,探讨汉防己甲素抗泡型包虫病的作用。　方法　将汉防己甲素、阿苯哒唑和汉防己甲素脂质体分别配制成 2 0 μg/ml、40 μg/ml、80 μg/ml 3个浓度 ,并且选择低、中剂量的汉防己甲素和阿苯哒唑合用 ,加入RPMI164 0培养基中 ,体外培养泡球蚴原头节 ,观察计数每天的死亡率 ,直到所有的用药组头节全部死亡。　结果　汉防己甲素、阿苯哒唑低、中、高浓度组与相应的对照组比较 ,原头节死亡率的差异均有统计学意义 (P <0 .0 5 ) ;汉防己甲素脂质体在中、高浓度下与对照组的原头节死亡率差异有统计学意义(P <0 .0 5 ) ;联合用药组与单药组的原头节死亡率差异亦有统计学意义 (P <0 .0 5 )。　结论　汉防己甲素体外具有抑制泡球蚴原头节的作用 ,并且与阿苯哒唑联合使用时具有一定的协同作用。     

汉防己甲素和阿苯达唑体外抗细粒棘球蚴原头节作用的观察

通过比较汉防己甲素和阿苯达唑体外抗细粒棘球蚴原头节作用，以探讨中药单体汉防己甲素抗包虫病的作用，将汉防己甲素和阿苯达唑分别配成不同浓度，加入RPMI 1640培养基中，体外培养细粒棘球蚴原头节，观察其每天的死亡率。结果显示各用药组原头节的死亡率分别与对照组相比，差异均有统计学意义(P＜0．01)；阿苯达唑和汉防己甲素联合组与阿苯达唑组，汉防己甲素低、中浓度组相比，差异有统计学意义(P＜0．05)，而与汉防己甲素高浓度组相比，差别无统计学意义(P＞0．05)。表明汉防己甲素在体外有明显的抗原头节作用；汉防己甲素体外抗原头节作用与阿苯达唑相当．同时两药联合抗原头节效果明显优于单药组，两药联合可能具有协同效果。     

磺胺类药物对结核分枝杆菌的体外抑菌作用及与其他抗结核药物相互作用的研究

目的 评价磺胺甲噁唑（sulfamethoxazole,SMX）和甲氧苄啶（trimethoprim,TMP）对结核分枝杆菌的体外抑菌作用,并探讨SMX与其他抗结核药物的体外相互作用。 方法 采用微孔板Alamar blue法测定TMP联合SMX对121株结核分枝杆菌临床株的最低抑菌浓度(MIC)。同时采用分层整群抽样设计方法,抽取18株结核分枝杆菌临床分离株观察SMX在与利福平、异烟肼、链霉素、乙胺丁醇、卡那霉素、氧氟沙星、利福布丁联用时MIC值的影响,以H37Rv为对照,通过计算分级抑菌浓度指数（FICI）,观察SMX与其他抗结核药物之间是否存在协同作用。采用SPSS 13.0统计软件进行统计学分析,MDR菌株、非MDR菌株、敏感菌株间MIC的比较采用非参数秩和检验,以P<0.05为差异有统计学意义。 结果90.08%(109/121)的结核分枝杆菌临床分离株可以被MIC为1/19（TMP∶SMX）μg/ml的复合制剂抑制生长, 5株菌株的“TMP∶SMX＝1∶19”的MIC为2/38 μg/ml,仅有7株“TMP∶SMX＝1∶19”的MIC≥2/38μg/ml,包括敏感株5株,MDR菌株2株。“TMP∶SMX＝1∶19”对敏感株、MDR菌株及非MDR菌株MIC间的差异没有统计学意义（χ²=0.111,P=0.946)。对于H37Rv,SMX与其他抗结核药联合用药后,除了利福布丁表现出协同作用（FICI为0.281）外,其余药物均表现为无关作用。对18株临床分离株,SMX与其他抗结核药联合用药后,77.78%（14/18）表现为与利福布丁协同,FICI范围为0.205～1.063。 结论TMP联合SMX有较好的抗结核分枝杆菌活性,并且这种活性与细菌对其他药物是否耐药无关;SMX与其他常用抗结核药的相互作用主要表现为无关。     

隐球菌临床及环境分离株对卡泊芬净与特比萘芬的体外联合药敏试验

目的　了解隐球菌临床及环境分离株对卡泊芬净与特比萘芬的体外联合抗菌活性。方法　采用美国国家实验室标准委员会 (NCCLS)M 2 7 A方案推荐的酵母菌微量稀释法及其微量稀释棋盘法 ,检测 78株新生隐球菌临床和环境分离株对卡泊芬净与特比萘芬的体外抗菌活性及其联合抗菌活性。结果　卡泊芬净和特比萘芬对新生隐球菌最小抑菌浓度 (MIC)值范围分别是 0 .2 5～ 32 μg/ml、2～16 μg/ml;几何均数分别是 32 μg/ml、8μg/ml。联合药敏试验结果显示 ,两者联合后对其中 5 %菌株有协同作用 ,4 2 %菌株有累加作用及 5 3%菌株有无关作用 ,任何菌株均无拮抗作用。同时卡泊芬净的MIC几何均数由 2 6 .8μg/ml降至 2 0 .6 μg/ml(P <0 .0 0 0 1) ,特比萘芬的MIC几何均数由7.9μg/ml降至 1.3μg/ml(P <0 .0 0 0 1)。此外 ,有 4株菌株对卡泊芬净药物敏感 ,其MIC分别是 2 μg/ml、2 μg/ml、0 .5 μg/ml、0 .2 5 μg/ml。 结论　卡泊芬净与特比萘芬的体外联合药敏试验表明 ,两者联合应用对新生隐球菌具有较好的体外抗菌活性     

脓肿分枝杆菌耐利福平机制的研究

目的 探讨脓肿分枝杆菌耐利福平的机制。方法 采用棋盘微量稀释法,分别测定利福平在加入不同浓度的改变细胞壁通透性的试剂和主动外排泵抑制剂时对脓肿分枝杆菌的最低抑菌浓度。通过利福平对脓肿分枝杆菌的最低抑菌浓度的变化情况来分析细胞壁通透性和主动外排在脓肿分枝杆菌耐利福平机制中的作用。结果 随着TWEEN-80、Trixon X-100、甲苯、乙醚、CCCP、利血平和泮托拉唑浓度的增加,利福平对脓肿分枝杆菌的最低抑菌浓度逐渐降低。对于TWEEN-80、Trixon X-100、CCCP和泮托拉唑,利福平对脓肿分枝杆菌的最低抑菌浓度由512 μg/mL降至小于32 μg/mL,0.1%的TWEEN-80、0.006 25%的Trixon X-100、0.1 μg/mL的CCCP和32 μg/mL的泮托拉唑为最适浓度;对于甲苯、乙醚和利血平,利福平对脓肿分枝杆菌的最低抑菌浓度由512 μg/mL降至64 μg/mL,0.25%的甲苯、0.25%的乙醚和8 μg/mL的利血平为最适浓度。它们均能促进利福平对脓肿分枝杆菌的抑菌作用。结论 细胞壁通透性和主动外排在脓肿分枝杆菌耐利福平的机制中有重要作用。     

鱼腥草素钠联合氨苄西林对表皮葡萄球菌的抗菌作用

目的：检测鱼腥草素钠联合氨苄西林（ AM）对表皮葡萄球菌（ SE）的抗菌作用。方法利用二倍稀释法、微量棋盘法、杀菌效力评估法对8株临床分离的SE进行药物敏感性测定。结果鱼腥草素钠、AM单独对SE的最小抑菌浓度（MIC）分别为12．5～50μg/mL和2～64μg/mL。鱼腥草素钠联合AM作用于8株SE后,鱼腥草素钠和AM的MIC分别下降了8～16倍和4～8倍,部分抑菌浓度指数（FICI）为0．25～0．375,二者联合作用于8株SE的杀菌效力均为协同效应。结论鱼腥草素钠与AM联合对SE具有抗菌协同作用。     

Synergistic effect of two combinations of antituberculous drugs against Mycobacterium tuberculosis

Fluoroquinolones such as ofloxacin are promising drugs to treat drug-resistant tuberculosis (TB) and have been proposed for shortening the treatment of TB. The objectives were to study the synergistic effect of the combinations of three drugs and to evaluate the in?vitro interactions of the following combinations against Mycobacterium tuberculosis: A) isoniazid, rifampicin, and ethambutol and B) ofloxacin, rifampicin, and ethambutol using an adaptation of the two-dimensional chequerboard assay. A total of 12 isolates resistant to isoniazid or to isoniazid-streptomycin and 11 drug-susceptible isolates were tested. The fractional inhibitory concentration (FICI) was calculated as follows: FICI?=?FIC(A)?+?FICB?+?FIC(C)?=?A/MIC(A)?+?B/MIC(B)?+?C/MIC(C) where A, B and C were the MICs of each antibiotic in combination and MIC(A), MIC(B) and MIC(C) were the individual MICs. The FICI was interpreted as synergism when the value was ≤0.75. In combination A, 11 drug-susceptible isolates decreased the individual MIC one to three dilutions, showing indifferent activity in 81.8% (FICI?=?0.88-1.6) and synergistic activity in 18.1% (FICI?=?0.6). In combination B, 21 out of the 23 isolates studied (91.3%) showed synergism (FICI?=?0.31-0.62). In conclusion, adaptation of the two-dimensional chequerboard assay is a reliable method to study in?vitro three-drug combinations. Both three-drug combinations tested may be useful against drug-resistant isolates, although the combination including ofloxacin showed better efficacy, being of potential use in drug-susceptible and isoniazid-resistant isolates.     

Does the Piperacillin Minimum Inhibitory Concentration for Pseudomonas aeruginosa Influence Clinical Outcomes of Children With Pseudomonal Bacteremia?

Background.?The Clinical and Laboratory Standards Institute (CLSI) recently elected to adjust the previous piperacillin susceptibility breakpoint of ≤64 μg/mL against Pseudomonas aeruginosa to ≤16 μg/mL, based largely on pharmacokinetic-pharmacodynamic (PK-PD) modeling studies. Data on whether PK-PD modeling correlates with clinical outcomes in children are needed before resorting to broader classes of antibiotics to treat P. aeruginosa. Methods.?We performed a retrospective cohort study of children with P. aeruginosa bacteremia between 2001 and 2010 who were prescribed piperacillin. Baseline characteristics and clinical outcomes of children with piperacillin minimum inhibitory concentrations (MICs) of ≤16 μg/mL and of 32-64 μg/mL were compared. The primary outcome was 30-day mortality. Results.?There were 170 children with P. aeruginosa bacteremia receiving piperacillin therapy who met inclusion criteria. One hundred twenty-four (72%) children had piperacillin MICs of ≤16 μg/mL and 46 (28%) children had piperacillin MICs of 32-64 μg/mL. There was no significant difference in baseline characteristics between the 2 groups. Thirty-day mortality was 9% and 24% in children with a piperacillin MIC of ≤16 μg/mL and of 32-64 μg/mL, respectively. Using multivariable logistic regression, children with elevated MICs had increased odds of mortality compared with children with lower MICs (odds ratio, 3.21; 95% confidence interval, 1.26-8.16). Conclusions.?Our finding that elevated piperacillin MICs are associated with higher mortality in children supports the recent CLSI recommendation to lower the breakpoint of piperacillin against P. aeruginosa to ≤16 μg/mL. Alternate therapeutic choices should be considered when piperacillin MICs against P. aeruginosa are ≥32 μg/mL.     

Antimicrobial activities of fidaxomicin

Fidaxomicin is bactericidal against Clostridium difficile. The combined results of 8 in vitro studies of 1323 C. difficile isolates showed the minimum inhibitory concentration (MIC) range of fidaxomicin to be ≤ 0.001-1 μg/mL, with a maximum MIC for inhibition of 90% of organisms (MIC(90)) of 0.5 μg/mL. Isolates from 2 phase III clinical trials demonstrated that fidaxomicin MICs of baseline isolates did not predict clinical cure, failure, or recurrence of C. difficile infections. No resistance to fidaxomicin developed during treatment in either study, although a single strain recovered from a cured patient had an elevated MIC of 16 μg/mL at the time of recurrence. For 135 strains, OP-1118, a major metabolite, had an MIC for inhibition of 50% of organisms of 4 μg/mL and an MIC(90) of 8 μg/mL. Changes in inoculum size (10(2)-10(5) colony-forming units/spot) or cation concentrations of calcium or magnesium appeared to have no effect on fidaxomicin MICs. Fidaxomicin has little or no activity against gram-negative aerobes and anaerobes or yeast.