Drug-resistant

耐药
  • 文章类型: Journal Article
    自2022年以来,欧洲已经有4例广泛耐药的淋病奈瑟菌,序列类型16406,对头孢曲松具有抗性,对阿奇霉素具有高度抗性。我们报告了2023年来自法国的2例新病例,涉及与来自欧洲的4例以及来自柬埔寨的分离株遗传相关的菌株。
    Since 2022, Europe has had 4 cases of extensively drug-resistant Neisseria gonorrhoeae, sequence type 16406, that is resistant to ceftriaxone and highly resistant to azithromycin. We report 2 new cases from France in 2023 involving strains genetically related to the 4 cases from Europe as well as isolates from Cambodia.
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  • 文章类型: Journal Article
    中枢神经系统(CNS)疾病影响全球数百万人,相当比例的人经历耐药形式,而传统药物无法提供足够的癫痫发作控制。本摘要深入研究了最新进展和创新疗法,旨在解决中枢神经系统相关的耐药性癫痫(DRE)管理的复杂挑战。精准医学的理念开辟了癫痫医治的新门路。草药如姜黄素,银杏叶,人参,bacopamonnieri,ashwagandha,红景天通过多种机制影响BDNF途径。这些包括激活CREB,抑制NF-κB,调节神经递质,减少氧化应激,和抗炎作用。通过促进BDNF的表达和活性,这些草药支持神经可塑性,认知功能,和整体神经元健康。具有不同作用机制的新型抗癫痫药物(AED)在传统药物步履蹒跚的难治性病例中显示出疗效。此外,将现有药物重新用于抗癫痫药物是一种具有成本效益的策略,可以拓宽治疗选择范围.大麻二酚(CBD),源自大麻草药,它的抗惊厥特性引起了人们的关注,为难治性癫痫提供潜在的辅助治疗。总之,最新进展和创新疗法代表了管理耐药癫痫的多方面方法.利用精准医疗,神经刺激技术,新型药物,和补充疗法,临床医生可以优化治疗结果,提高难治性癫痫患者的预期寿命.基因测试和生物标志物识别现在允许针对个体患者概况定制的个性化治疗方法。利用下一代测序技术,研究人员已经阐明了基因突变。
    Central Nervous System (CNS) disorders affect millions of people worldwide, with a significant proportion experiencing drug-resistant forms where conventional medications fail to provide adequate seizure control. This abstract delves into recent advancements and innovative therapies aimed at addressing the complex challenge of CNS-related drug-resistant epilepsy (DRE) management. The idea of precision medicine has opened up new avenues for epilepsy treatment. Herbs such as curcumin, ginkgo biloba, panax ginseng, bacopa monnieri, ashwagandha, and rhodiola rosea influence the BDNF pathway through various mechanisms. These include the activation of CREB, inhibition of NF-κB, modulation of neurotransmitters, reduction of oxidative stress, and anti- inflammatory effects. By promoting BDNF expression and activity, these herbs support neuroplasticity, cognitive function, and overall neuronal health. Novel antiepileptic drugs (AEDs) with distinct mechanisms of action demonstrate efficacy in refractory cases where traditional medications falter. Additionally, repurposing existing drugs for antiepileptic purposes presents a cost-effective strategy to broaden therapeutic choices. Cannabidiol (CBD), derived from cannabis herbs, has garnered attention for its anticonvulsant properties, offering a potential adjunctive therapy for refractory seizures. In conclusion, recent advances and innovative therapies represent a multifaceted approach to managing drug-resistant epilepsy. Leveraging precision medicine, neurostimulation technologies, novel pharmaceuticals, and complementary therapies, clinicians can optimize treatment outcomes and improve the life expectancy of patients living with refractory seizures. Genetic testing and biomarker identification now allow for personalized therapeutic approaches tailored to individual patient profiles. Utilizing next-generation sequencing techniques, researchers have elucidated genetic mutations.
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  • 文章类型: Journal Article
    耐药结核病(TB)由于其诊断的复杂性,在南非引起了重大的公共卫生问题,治疗,和管理。这项研究评估了XpertMTB/XDR测试通过使用存档的痰液沉淀物检测结核病患者耐药性的诊断性能。这项研究分析了2016年至2019年南非结核病患者的322份样本。以前通过表型和基因型方法表征。评估了XpertMTB/XDR测试检测异烟肼(INH)耐药性的能力,乙硫酰胺(ETH),氟喹诺酮类药物(FLQ),和二线注射药物(SLID)与表型药物敏感性测试(pDST)和全基因组测序(WGS)相比。文化,XpertMTB/RIFUltra,进行了XpertMTB/RIF(G4)检测以确定TB检测的敏感性和与本检测的一致性.使用复合参考标准的灵敏度,pDST,异烟肼的测序>90%,FLQ,阿米卡星(AMK),卡那霉素(KAN),和卷曲霉素(CAP)抗性,符合世卫组织这一类的目标产品概况标准。观察到对ETH抗性的较低敏感性为65.9%(95%CI:57.1-73.6)。与培养物相比,XpertMTB/XDR的灵敏度为98.3%(95%CI:96.1-99.3),特异性为100%(95%CI:86.7-100)。与G4相比,阳性百分比一致性(PPA)为98.8%(95%CI:93.7-99.8),阴性百分比一致性(NPA)为100.0%(95%CI:78.5-100.0),PPA为99.5%(95%CI:97.3-99.9),NPA为100.0%(95%CI:78.5-100.0)。该测试为快速检测耐药结核病提供了有希望的解决方案,并可以显着增强这种情况下的控制工作。
    Drug-resistant tuberculosis (TB) poses a significant public health concern in South Africa due to its complexity in diagnosis, treatment, and management. This study assessed the diagnostic performance of the Xpert MTB/XDR test for detecting drug resistance in patients with TB by using archived sputum sediments. This study analyzed 322 samples collected from patients diagnosed with TB between 2016 and 2019 across South Africa, previously characterized by phenotypic and genotypic methods. The Xpert MTB/XDR test was evaluated for its ability to detect resistance to isoniazid (INH), ethionamide (ETH), fluoroquinolones (FLQ), and second-line injectable drugs (SLIDs) compared with phenotypic drug susceptibility testing (pDST) and whole-genome sequencing (WGS). Culture, Xpert MTB/RIF Ultra, and Xpert MTB/RIF (G4) tests were performed to determine sensitivity and agreement with this test for TB detection. The sensitivities using a composite reference standard, pDST, and sequencing were >90% for INH, FLQ, amikacin (AMK), kanamycin (KAN), and capreomycin (CAP) resistance, meeting the WHO target product profile criteria for this class. A lower sensitivity of 65.9% (95% CI: 57.1-73.6) for ETH resistance was observed. The Xpert MTB/XDR showed a sensitivity of 98.3% (95% CI: 96.1-99.3) and specificity of 100% (95% CI: 86.7-100) compared with culture, a positive percent agreement (PPA) of 98.8% (95% CI: 93.7-99.8) and negative percent agreement (NPA) of 100.0% (95% CI: 78.5-100.0) compared with G4, and a PPA of 99.5% (95% CI: 97.3-99.9) and NPA of 100.0% (95% CI: 78.5-100.0) compared with Xpert MTB/RIF Ultra for detecting Mycobacterium tuberculosis. The test offers a promising solution for the rapid detection of drug-resistant TB and could significantly enhance control efforts in this setting.
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  • 文章类型: Journal Article
    化疗是膀胱癌的主要治疗方法,但是耐药性和副作用限制了其应用和治疗效果。在这里,我们构建了多柔比星(DOX)/COOH-介孔二氧化硅纳米颗粒/聚乙烯亚胺(PEI)/核酸嵌合体(DOX/MSN/Chimeras),以降低化疗药物的毒性和膀胱癌细胞的耐药性。透射电镜显示PEI被包覆在直径约为150nm的DOX/MSN/BSA纳米粒子上。DOX/MSN/PEI可以控制DOX释放超过48小时,突释率显著低于DOX/MSN。免疫组化结果显示DOX/MSN/Chimera与膀胱癌细胞特异性结合,并显著抑制DOX耐药膀胱癌细胞PI3K的表达和增殖。DOX/MSN/嵌合体促进耐药膀胱癌细胞凋亡,优于DOX/MSN/适配体或DOX/MSN。我们进一步进行了动物实验,发现DOX/MSN/Chimera可以减少体内移植肿瘤的体积。与DOX/MSN/Aptamer组相比,增殖率显著降低,凋亡细胞比例显著增加。通过对肾脏和肺的组织学观察,我们认为DOX/MSN/Chimera能有效降低化疗药物对正常组织的损伤。总之,我们构建了COOH-MSN/核酸嵌合体,用于靶向递送siRNA和抗癌药物。我们的研究为耐药膀胱癌的个性化和靶向治疗提供了新的方法。
    Chemotherapy is the main treatment for bladder cancer, but drug resistance and side effects limit its application and therapeutic effect. Herein, we constructed doxorubicin (DOX)/COOH-mesoporous silica nanoparticle/polyethylenimine (PEI)/nucleic acid chimeras (DOX/MSN/Chimeras) to reduce the toxicity of chemotherapy drugs and the resistance of bladder cancer cells. Transmission electron microscopy showed that PEI was coated on the DOX/MSN/BSA nanoparticles with a diameter of about 150 nm. DOX/MSN/PEI could control DOX release for over 48 h, and the sudden release rate was significantly lower than DOX/MSN. Immunohistochemical results showed that DOX/MSN/Chimera specifically bound to bladder cancer cells, and markedly inhibited PI3K expression and proliferation of DOX-resistant bladder cancer cells. DOX/MSN/Chimera promoted the apoptosis of drug-resistant bladder cancer cells, which was superior to DOX/MSN/Aptamer or DOX/MSN. We further carried out animal experiments and found that DOX/MSN/Chimera could reduce the volume of transplanted tumors in vivo. Compared with DOX/MSN/Aptamer group, the proliferation rate was significantly decreased and the proportion of apoptotic cells was highly increased. Through the histological observation of kidneys and lungs, we believed that DOX/MSN/Chimera can effectively reduce the damage of chemotherapy drugs to normal tissues. In conclusion, we constructed a COOH-MSN/nucleic acid chimera conjugate for the targeted delivery of siRNA and anti-cancer drugs. Our study provides a new method for personalized and targeted treatment of drug-resistant bladder cancer.
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  • 文章类型: Journal Article
    目的:。免疫功能低下的患者可能经历流感病毒的长时间脱落,可能导致严重的感染。应评估神经氨酸酶抑制剂单一疗法的替代方案,以完全抑制病毒复制并防止耐药突变。
    方法:。我们调查了在不同治疗策略后,造血干细胞移植受者中持续性甲型流感和人类冠状病毒OC43(HCoV-OC43)共感染的临床和病毒学演变。
    结果:。连续奥司他韦和扎那米韦单一疗法未能控制两种感染,阳性结果持续110天以上。由于神经氨酸酶突变(E119V和R292K),随后缺失(del245-248),这导致了高度耐药的奥司他韦菌株的出现。同时保持对扎那米韦的敏感性。宿主内病毒多样性数据表明,这些治疗方法影响了流感病毒的病毒多样性,但不是HCoV-OC43.考虑到患者的基本情况和长期病毒脱落对肺功能的影响,消灭流感病毒是必要的。结合扎那米韦和巴洛沙韦-marboxil的10天方案有效地控制了流感病毒的复制,并与HCoV-OC43的清除有关,最终导致全面的呼吸恢复。
    结论:这些观察结果强调了进一步研究联合治疗作为免疫功能低下患者根除流感的主要方法的重要性。
    OBJECTIVE: Immunocompromised patients may experience prolonged shedding of influenza virus potentially leading to severe infections. Alternatives to monotherapy with neuraminidase inhibitors should be evaluated to entirely suppress viral replication and prevent drug-resistant mutations.
    METHODS: We investigated the clinical and virological evolution in a case of persistent influenza A and human coronavirus OC43 (HCoV-OC43) coinfection in a hematopoietic stem cell transplant recipient after different therapeutic strategies.
    RESULTS: Successive oseltamivir and zanamivir monotherapies failed to control both infections, with positive results persisting for over 110 days each. This led to the emergence of highly resistant oseltamivir strains due to neuraminidase mutations (E119V and R292K) followed by a deletion (del245-248), while maintaining sensitivity to zanamivir. The intra-host viral diversity data showed that the treatments impacted viral diversity of influenza virus, but not of HCoV-OC43. Considering the patient\'s underlying condition and the impact of prolonged viral shedding on pulmonary function, eradicating the influenza virus was necessary. A 10-day regimen combining zanamivir and baloxavir-marboxil effectively controlled influenza virus replication and was associated with the clearance of HCoV-OC43, finally resulting in comprehensive respiratory recovery.
    CONCLUSIONS: These observations underscore the importance of further investigating combination treatments as the primary approach to achieve influenza eradication in immunocompromised patients.
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  • 文章类型: Journal Article
    最近,耐药性颞叶癫痫(TLE)与microRNA(miR)-146a(MIR-146A)(rs2910164)和钠电压门控通道α亚基1(SCN1A)(rs2298771和rs3812718)基因中的单核苷酸变体(SNV)相关。此外,在巴西,没有研究表明这些SNV与耐药和药物反应性TLE的易感性之间存在关联.因此,通过实时聚合酶链反应(RT-PCR)评估了120例TLE患者(55例药物反应性和65例耐药)的脱氧核糖核酸(DNA)样本。来自巴西突变在线档案(ABraOM,来自葡萄牙ArquivoBrasileiroOn-linedeMutaçšes),一个包含巴西人口基因组变异的储存库,被添加为研究的SNV的对照种群。通过定量RT-PCR(qRT-PCR)进行MIR-146A和SCN1A相对表达。使用0.05的α误差进行统计分析方案。对于所有研究的SNV,TLE患者样品和ABraOM对照样品处于Hardy-Weinberg平衡。对于rs2910164,纯合基因型(CC)的频率(15.00%vs.9.65%)和C等位基因(37.80%vs.29.97%)在TLE患者中优于TLE疾病风险较高的对照组[比值比(OR)=1.89(95%置信区间(95CI)=1.06-3.37);OR=1.38(95CI=1.04-1.82),分别]。药物反应性患者的CC基因型频率也较高[21.81%vs.9.65%;OR=2.58(95CI=1.25-5.30)]和C等位基因[39.09%vs.29.97%;与对照组相比,OR=1.50(95CI=1.01-2.22)]。对于rs2298771,杂合基因型(AG)的频率(51.67%vs.40.40%)在TLE患者中优于TLE疾病风险较高的对照组[OR=2.42(95CI=1.08-5.41)]。耐药患者的AG频率较高[56.92%vs.40.40%;与对照组相比,OR=3.36(95CI=1.04-17.30)]。对于rs3812718,两个研究组的基因型和等位基因患病率相似。与GC的药物反应性患者相比,耐药患者的MIR-146A相对表达水平较低(1.6vs.0.1,p值=0.049)和CC(1.8vs.0.6,p值=0.039)。此外,来自TLE患者的样本中的SCN1A相对表达水平在AG中明显更高[2.09vs.1.10,p值=0.038]和GG(3.19vs.1.10,p值<0.001)与AA基因型相比。总之,rs2910164-CC和rs2298771-AG基因型具有显著的风险影响,分别,关于反应性疾病和抗性疾病,可能是由于核因子κB(NF-kB)和SCN1A功能的上调。
    The drug-resistant temporal lobe epilepsy (TLE) has recently been associated with single nucleotide variants (SNVs) in microRNA(miR)-146a (MIR-146A) (rs2910164) and Sodium Voltage-Gated Channel Alpha Subunit 1 (SCN1A) (rs2298771 and rs3812718) genes. Moreover, no studies have shown an association between these SNVs and susceptibility to drug-resistant and drug-responsive TLE in Brazil. Thus, deoxyribonucleic acid (DNA) samples from 120 patients with TLE (55 drug-responsive and 65 drug-resistant) were evaluated by real-time polymerase chain reaction (RT-PCR). A total of 1171 healthy blood donor individuals from the Online Archive of Brazilian Mutations (ABraOM, from Portuguese Arquivo Brasileiro On-line de Mutações), a repository containing genomic variants of the Brazilian population, were added as a control population for the studied SNVs. MIR-146A and SCN1A relative expression was performed by quantitative RT-PCR (qRT-PCR). The statistical analysis protocol was performed using an alpha error of 0.05. TLE patient samples and ABraOM control samples were in Hardy-Weinberg equilibrium for all studied SNVs. For rs2910164, the frequencies of the homozygous genotype (CC) (15.00% vs. 9.65%) and C allele (37.80% vs. 29.97%) were superior in patients with TLE compared to controls with a higher risk for TLE disease [odds ratio (OR) = 1.89 (95% confidence interval (95%CI) = 1.06-3.37); OR = 1.38 (95%CI = 1.04-1.82), respectively]. Drug-responsive patients also presented higher frequencies of the CC genotype [21.81% vs. 9.65%; OR = 2.58 (95%CI = 1.25-5.30)] and C allele [39.09% vs. 29.97%; OR = 1.50 (95%CI = 1.01-2.22)] compared to controls. For rs2298771, the frequency of the heterozygous genotype (AG) (51.67% vs. 40.40%) was superior in patients with TLE compared to controls with a higher risk for TLE disease [OR = 2.42 (95%CI = 1.08-5.41)]. Drug-resistant patients presented a higher AG frequency [56.92% vs. 40.40%; OR = 3.36 (95%CI = 1.04-17.30)] compared to the control group. For rs3812718, the prevalence of genotypes and alleles were similar in both studied groups. The MIR-146A relative expression level was lower in drug-resistant compared to drug-responsive patients for GC (1.6 vs. 0.1, p-value = 0.049) and CC (1.8 vs. 0.6, p-value = 0.039). Also, the SCN1A relative expression levels in samples from TLE patients were significantly higher in AG [2.09 vs. 1.10, p-value = 0.038] and GG (3.19 vs. 1.10, p-value < 0.001) compared to the AA genotype. In conclusion, the rs2910164-CC and rs2298771-AG genotypes are exerting significant risk influence, respectively, on responsive disease and resistant disease, probably due to an upregulated nuclear factor kappa B (NF-kB) and SCN1A loss of function.
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  • 文章类型: Journal Article
    在过去的2000年里,结核病(TB)导致的死亡人数比任何其他传染病都多。近年来,已经恢复了针对结核病药物的研发(R&D)努力。这是因为迫切需要抗击这种疾病的全球传播,并为药物敏感和耐药菌株开发改进的疗法。许多新的结核病候选药物最近进入临床试验,标志着经过几十年的忽视,这一地区开始了重生。问题在于,每年被确定为潜在抗结核药物的数百种化合物中,很少有化合物真正进入临床开发阶段。这种观点侧重于结核病新药开发中涉及的主要障碍和方法。这将有助于药物化学家更好地了解结核病药物挑战并开发新的候选药物。
    Over the past 2000 years, tuberculosis (TB) has been responsible for more deaths than any other infectious disease. In recent years, there has been a recovery of research and development (R&D) efforts focused on TB drugs. This is driven by the pressing need to combat the global spread of the disease and develop improved therapies for both drug-sensitive and drug-resistant strains. Many new TB drug candidates have recently entered clinical trials, marking the beginning of a rebirth in this area after decades of neglect. The problem is that very few of the hundreds of compounds identified each year as potential anti-TB drugs really make it to the clinical development stage. This perspective focuses on the primary obstacles and approaches involved in the development of new medications for TB. This will help medicinal chemists better understand TB drug challenges and develop novel drug candidates.
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  • 文章类型: Journal Article
    目的:检验肌阵挛性癫痫发作可以演变为强直性癫痫发作的假设,我们记录了这种未被识别的癫痫发作类型的电临床特征.
    方法:我们观察到一种不同的癫痫发作模式,从肌阵挛性开始,没有回到发作间状态,随后演变成全身性强直性癫痫发作。提取了这次癫痫发作的详细症状和脑电图特征,和临床表现,回顾并分析了这种癫痫发作患者的药物治疗反应。
    结果:所有癫痫发作的发作均以前期的肌阵挛性和高振幅的广泛尖峰或多尖峰慢波放电为特征。紧随其后的是强直性癫痫发作的发生,以10Hz或更高频率的广义快速活动爆发为特征。这种未被认可的癫痫发作类型已被指定为肌阵挛性(MT)癫痫发作。在这项研究中,确定患有MT癫痫发作的患者人数为34。发现男性MT癫痫发作的患病率较高。虽然MT癫痫发作通常包括补品成分,应该注意的是,一些经历这种癫痫发作类型的患者从未出现过孤立性强直性癫痫发作。未进一步定义的广义癫痫(GE)约占诊断病例的三分之一,其次是Lennox-Gastaut综合征和癫痫伴肌阵挛性-Atonic癫痫发作。与其他类型的癫痫相比,伴有MT发作的GE显示出更有利的预后。
    结论:肌阵挛性癫痫发作的分类代表了理解全身性癫痫发作发生的一种新方法,可以为临床医生在癫痫诊断方面提供有价值的帮助。
    OBJECTIVE: To test the hypothesis that myoclonic seizures can evolve to tonic seizures, we documented the electroclinical features of this under-recognized seizure type.
    METHODS: We observed a distinct seizure pattern starting with myoclonus without returning to an interictal state, which subsequently evolved into generalized tonic seizures. The detailed symptomatic and electroencephalographic characteristics of this seizure were extracted, and the clinical manifestations, drug curative responses in patients with this seizure were reviewed and analyzed.
    RESULTS: The onset of all seizures was characterized by a preceding period of myoclonus and bursts of generalized spike or poly-spike slow wave discharges with high amplitude. This was closely followed by the occurrence of tonic seizures, which were distinguished by bursts of generalized fast activity at 10 Hz or higher frequency. This under-recognized seizure type has been designated as myoclonic-to-tonic (MT) seizure. The number of patients identified with MT seizures in this study was 34. The prevalence rate of MT seizures was found to be higher in males. While MT seizures typically included a tonic component, it should be noted that some patients experiencing this seizure type never presented with isolated tonic seizures. Generalized Epilepsy not further defined (GE) accounted for approximately one-third of the diagnosed cases, followed by Lennox-Gastaut syndrome and Epilepsy with Myoclonic-Atonic seizures. In comparison to other types of epilepsy, GE with MT seizures demonstrated a more favorable prognosis.
    CONCLUSIONS: The classification of myoclonic-to-tonic seizure represents a novel approach in comprehending the ictogenesis of generalized seizures and can provide valuable assistance to clinicians in epilepsy diagnosis.
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  • 文章类型: Journal Article
    耐药细菌构成了当前药物治疗的一大障碍。迫切需要发现具有新颖化学和生物学特征的抗菌药物。我们的工作旨在合成,抗菌效果评价,和LCC的毒性,一种天然存在的查尔酮。合成路线包括六个步骤,提供10%的总收益率。LCC对革兰氏阳性细菌有影响(MIC=6.2-50.0µg/mL),分枝杆菌种类(MIC=36.2-125µg/mL),和幽门螺杆菌(MIC=25µg/mL)。LCC抑制MSSA和MRSA生物膜的形成,表明两种菌株的MBIC50值为6.25μg/mL。荧光显微镜的调查,使用PI和SYTO9作为荧光团,表明LCC能够破坏金黄色葡萄球菌膜,与Nisin相似。使用Galleriamelonella幼虫进行的系统毒性分析显示,LCC在80小时处理后在100µg/mL时不会致死。这些数据表明LCC作为一种化合物的新用途,在抗菌药物发现和医疗设备涂层中具有潜在的应用。
    Drug-resistant bacteria constitute a big barrier against current pharmacotherapy. Efforts are urgent to discover antibacterial drugs with novel chemical and biological features. Our work aimed at the synthesis, evaluation of antibacterial effects, and toxicity of licochalcone C (LCC), a naturally occurring chalcone. The synthetic route included six steps, affording a 10% overall yield. LCC showed effects against Gram-positive bacteria (MIC = 6.2-50.0 µg/mL), Mycobacterium species (MIC = 36.2-125 µg/mL), and Helicobacter pylori (MIC = 25 µg/mL). LCC inhibited the biofilm formation of MSSA and MRSA, demonstrating MBIC50 values of 6.25 μg/mL for both strains. The investigations by fluorescence microscopy, using PI and SYTO9 as fluorophores, indicated that LCC was able to disrupt the S. aureus membrane, similarly to nisin. Systemic toxicity assays using Galleria mellonella larvae showed that LCC was not lethal at 100 µg/mL after 80 h treatment. These data suggest new uses for LCC as a compound with potential applications in antibacterial drug discovery and medical device coating.
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  • 文章类型: Journal Article
    耐药细菌的出现,由金属β-内酰胺酶(MBL)促进,在临床耐药细菌感染的管理中,抗生素的有效使用存在重大障碍。AFM-1是源自粪产碱菌的MBL,与NDM-1家族具有86%同源性。AFM-1和NDM-1均显示出水解氨苄西林和其他β-内酰胺抗生素的能力。然而,它们的底物亲和力各不相同,这种变化的具体原因仍然未知。我们提出了AFM-1的高分辨率结构。AFM-1的活性中心结合两个锌离子,活性中心关键氨基酸残基的构象与NDM-1一致。然而,AFM-1的底物结合袋比NDM-1小得多。此外,Loop3区氨基酸残基的突变,与NDM-1相比,导致在该区域形成由疏水氨基酸残基组成的致密疏水斑块,这有利于底物结合。我们的发现为理解AFM-1对底物具有高亲和力的分子机制奠定了基础,并为解决B1MBL引起的耐药性问题提供了新的理论基础。
    The emergence of drug-resistant bacteria, facilitated by metallo-beta-lactamases (MBLs), presents a significant obstacle to the effective use of antibiotics in the management of clinical drug-resistant bacterial infections. AFM-1 is a MBL derived from Alcaligenes faecalis and shares 86% homology with the NDM-1 family. Both AFM-1 and NDM-1 demonstrate the ability to hydrolyze ampicillin and other β-lactam antibiotics, however, their substrate affinities vary, and the specific reason for this variation remains unknown. We present the high-resolution structure of AFM-1. The active center of AFM-1 binds two zinc ions, and the conformation of the key amino acid residues in the active center is in accordance with that of NDM-1. However, the substrate-binding pocket of AFM-1 is considerably smaller than that of NDM-1. Additionally, the mutation of amino acid residues in the Loop3 region, as compared to NDM-1, results in the formation of a dense hydrophobic patch comprised of hydrophobic amino acid residues in this area, which facilitates substrate binding. Our findings lay the foundation for understanding the molecular mechanism of AFM-1 with a high affinity for substrates and provide a novel theoretical foundation for addressing the issue of drug resistance caused by B1 MBLs.
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