In vitro synergistic effect of Hibiscus sabdariffa aqueous extract in combination with standard antibiotics against Helicobacter pylori clinical isolates

Context The increasing problem of drug-resistant strains has led to the failure of current treatment regimens of Helicobacter pylori (HP) infection. Recently, a new treatment strategy has been developed to overcome the problem by using natural products in combination with antibiotics to enhance the treatment efficacy.

Objective The antimicrobial combinatory effect of the aqueous extract of Hibiscus sabdariffa L. (Malvaceae) (AEHS) with antibiotics (clarithromycin, CLA; amoxicillin, AMX; metronidazole, MTZ) has been evaluated in vitro against HP strains.

Materials and methods Hibiscus calyces (35?g) were brewed in 250?mL of boiled water for 30?min, and minimum inhibitory concentrations (MICs) were determined by agar dilution method. The checkerboard assay was used to evaluate the antimicrobial combinatory effect according to the sum of fractional inhibitory concentration (∑FIC) indices.

Results In this study, AEHS exerted remarkable bacteriostatic effect against all HP strains tested with MICs values ranging from 9.18 to 16.68?μg/mL. Synergy effect of AEHS with CLA or MTZ was obtained against four of seven HP strains tested with ∑FIC ranging from 0.21 to 0.39. The additive effect of AEHS with AMX was obtained against five of seven HP strains tested with ∑FIC ranging from 0.61 to 0.91.

Conclusion This study presents AEHS as a potent therapeutic candidate alone, or in combination with antibiotics for the treatment of HP infection.     

抗菌肽抗菌机制及与抗生素协同作用的研究进展

抗菌肽(antimicrobial peptides, AMPs)是一种新型抗生素,对多种细菌,多重耐药细菌均具有抗菌活性。然而,其副作用也是制约抗菌肽研发的主要障碍。研究者使用模式细胞膜,揭示抗菌肽与细胞膜之间的作用方式,开展抗菌肽开发和筛选研究。另外,研究者还将抗菌肽与常规抗生素联合使用,可以协同提高抗菌效果。研究初步揭示了AMPs和常规抗生素之间协同作用的机制。本综述探讨了模式细胞膜在AMPs发现筛选中的应用,及AMPs和常规抗生素之间联合用药的研发现状。     

万古霉素与β-内酰胺类联合对MRS的协同抗菌活性

目的比较万古霉素与不同β-内酰胺类、利福平、庆大霉素和红霉素分别联合对34株耐甲氧西林葡萄球菌的协同抗菌活性。方法应用纸片扩散法测定不同抗生素纸片在脑心浸液琼脂板上的抑菌圈；棋盘协同试验应用琼脂稀释法；分数抑菌浓度指数由万古霉素与亚胺培南、苯唑西林和利福平联合获得的分数抑菌浓度的和。万古霉素与其它抗生素的协同作用包括青霉素、苯唑西林、头孢唑林、头孢他啶、亚胺培南、哌拉西林／三唑巴坦、庆大霉素和红霉素应用改良的纸片扩散法。结果万古霉素明显增加β-内酰胺类抗菌药物对6株耐甲氧西林葡萄球菌的抗菌活性，青霉素的抑菌圈直径增加最大，其他依次为苯唑西林、头孢唑林、亚胺培南、哌拉西林／三唑巴坦和头孢他啶，对红霉素和庆大霉素的抑菌圈基本无影响。棋盘法显示万古霉素与亚胺培南、苯唑西林和利福平的联合协同百分比依次为91.2％（31／34）、85.3％（29／34）和35．3％（12／34），对9株万古霉素异质性耐药葡萄球菌的协同百分比依次为100％、100％和33．3％。结论尽管万古霉素与利福平联合有协同作用，但不如万古霉素与β-内酰胺类抗菌药物联合的协同作用强。因此通过改良的纸片扩散协同试验选择与万古霉素最具协同作用的β-内酰胺类抗菌药物。     

低频超声与抗菌药物协同增效研究进展

细菌耐药日益严重,单一抗菌药物难以完全杀灭耐药菌。应用低频超声技术联合抗菌药物,无论是对于浮游态菌还是生物被膜态菌,都能增强抗菌药物的杀菌或抑菌作用。其机制主要为空化效应。目前,低频超声技术已探索性应用于人体局部感染治疗中。作为一种可靶向治疗的非侵入性疗法,低频超声具有很大的临床应用潜能。此外,低频超声技术在基因转染上具有优势,并可通过改变基因来影响细菌耐药性。     

物理抗微生物膜与常用抗菌药物对糖尿病足耐药菌株药敏情况的比较研究

目的 研究创新物理抗微生物膜对临床糖尿病足耐药菌株的药敏情况.方法 对168例糖尿病足感染患者行病原菌分离培养,以最低抑菌浓度（MIC）稀释法进行药敏试验,比较常用抗菌药物及物理抗微生物膜的耐药情况.结果 分离出的63株菌株按构成比例由多到少依次为：金黄色葡萄球菌、铜绿假单胞菌、产气肠杆菌、阴沟肠杆菌、不动杆菌、表皮葡萄球菌.金黄色葡萄球菌对青霉素、左氧氟沙星、氨苄西林、苯唑西林、哌拉西林、庆大霉素、头孢唑林、头孢他啶等8种抗菌药物耐药率为23.5％～100％;铜绿假单胞菌为23.5％～97.8％;产气肠杆菌为7.5％～75.3％;阴沟肠杆菌为30.5％ ～ 94.6％;不动杆菌为21.6％ ～ 94.6％;表皮葡萄球菌为5.6％～83.8％.以上6种分离菌对物理抗微生物膜耐药率为0.结论 物理抗微生物膜具有广谱抗菌,对各种细菌敏感率高的特点,为临床治疗糖尿病足提供了有效,而且可避免耐药的物理学抗感染新方法.     

Synergistic effect of emodin in combination with ampicillin or oxacillin against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a substantial contributor to morbidity and mortality. In search of a natural products capable of inhibiting this multidrug resistant bacteria, we have investigated the antimicrobial activity of emodin (EM) isolated from Rheum palmatum L. (Polygonaceae) against 17 different strains of the bacterium. New antimicrobial activity was found using the paper disc diffusion method, agar dilution as well as checkerboard method. Against the 17 strains, the disc diffusion test was in the range of 18–30?mm, and the minimum inhibitory concentrations (MICs) of EM were in the range of 1.5–25 μg/mL. From those results we performed the checkerboard test to determine the synergism of EM in combination with ampicillin (AM) or oxacillin (OX) against all strains. The combined activity of EM and two antimicrobial agents (AM, OX) against all strains resulted in a fractional inhibitory concentrations index (FICI) ranging from 0.37–0.5 and from 0.37–0.75, respectively. The effect of EM with AM and OX was found to be synergistic or partially synergistic. We found that EM reduced the MICs of AM and OX. EM and in combination with AM or OX could lead to the development of new combination antibiotics against MRSA infection.     

木犀草素与抗菌药体外联用抗耐甲氧西林金葡菌的作用研究

目的：考察木犀草素与抗菌药体外联用抗耐甲氧西林金葡菌的作用。方法：采用倍比稀释法测定药物最小抑菌浓度;通过双纸片法、微量棋盘稀释法和时间-杀菌曲线法等实验,评价木犀草素与抗菌药联用对耐甲氧西林金葡菌的抑菌效果。结果：木犀草素对受试MRSA菌株均有抑制作用,最小抑菌浓度为32～128 mg.L-1;其与某些喹诺酮类和氨基糖苷类抗菌药联用时的部分抑菌浓度指数小于或等于0.5,呈现协同抑菌作用,且联用时抗菌药用量较单用时明显减少;时间-杀菌曲线显示,其与抗菌药联用在12和24 h时的协同抑菌效果最好。结论：木犀草素具良好的抗耐甲氧西林金葡菌活性,并与喹诺酮类和氨基糖苷类抗菌药联用具协同抑菌作用。     

Isolation and characterization of novel peptides from chilli pepper seeds: antimicrobial activities against pathogenic yeasts.

Different types of antimicrobial peptides have been identified in seeds from different plant species. The aim of this study was to isolate and characterize peptides present in chilli pepper seeds (Capsicum annuum L.) and evaluate their toxic activities against some yeast species. Initially, proteins from seed flour were extracted in phosphate buffer, pH 5.4, for 3 h at 4 degrees C and the pellet obtained at 90% saturation with ammonium sulfate was heated at 80 degrees C for 15 min. The resulting suspension was clarified by centrifugation and the supernatant was extensively dialyzed against water; the peptide-rich extract was then named F/0-90. Cation-exchange chromatography was performed to separate low molecular mass proteins. One of the resulting fractions, named F3, enriched with basic proteins of 6-16 kDa, was submitted to reverse-phase chromatography in a C2/C18 column by HPLC, resulting in four fractions denominated RP1, RP2, RP3 and RP4. When these fractions were submitted to N-terminal sequencing, the comparative analysis in databanks revealed homology for two of these peptides, isolated from fractions RP3 and RP4, with sequences of proteinase inhibitors and 2S albumins, respectively. The F3 fraction, rich in peptides, inhibited the growth of yeasts Saccharomyces cerevisiae, Candida albicans, Candida parapsilosis, Candida tropicalis, Pichia membranifaciens, Kluyveromyces marxiannus and Candida guilliermondii. The RP3 and RP4 fractions showed high inhibitory activity against the growth of the yeast S. cerevisiae. The F3 fraction was also able to inhibit glucose-stimulated acidification of the medium by yeast cells of S. cerevisiae and to cause several morphological changes in different yeasts, such as cell wall disorganization, bud formation as well as the formation of pseudohyphae.     

头孢唑林联合舒巴坦对90株产酶菌的体外抗菌活性

用液体培养基试管二倍稀释法测定头孢唑林联合舒巴坦对常见临床分离产酶菌的最低抑菌浓度（ＭＩＣ），并与头孢唑林进行比较。９０株产酶菌中金葡球菌２０株、表葡球菌４株、大肠埃希氏菌３５株、克雷伯氏菌２５株、其它６株，产酶菌鉴定采用ｎｉｔｒｏｃｅｆｉｎ试棒。结果９０株产酶菌中３４株（３７．８％）对头孢唑林耐药（ＭＩＣ≥３２ｍｇ／Ｌ），而仅有１９株（２１．１％）对头孢唑林／舒巴坦（２１）耐药，两者比较有显著差异（Ｐ＜０．０５）。头孢唑林／舒巴坦（２１）对其中６５．６％菌株显示出协同或累加抗菌作用，与头孢唑林比较，ＭＩＣ降至其１／２～１／２８，其中包括２５株耐头孢唑林菌株。此外，对３５株产酶菌株测试，头孢唑林／舒巴坦（２１）较头孢唑林／舒巴坦（１１）显示出更强的体外抗菌活性。     

磷霉素与头孢哌酮/舒巴坦联用及分别联合其他抗生素对多重耐药鲍曼不动杆菌体外抗菌活性对比研究

目的 评价磷霉素与头孢哌酮/舒巴坦作为基础药物,二者联用及分别与亚胺培南、米诺环素的联合用药方案,用于多重耐药鲍曼不动杆菌的体外联合抗菌效应对比。方法 分离多重耐药鲍曼不动杆菌临床株30株,采用微量肉汤稀释棋盘法,测定不同浓度组合的抗生素联用最低抑菌浓度,并计算部分抑菌浓度指数(fractiona inhibitory concentration index, FICI)判定联合效应。将不同联合用药配伍方案进行对比,评价优劣。结果 磷霉素联合亚胺培南、头孢哌酮/舒巴坦联合亚胺培南、磷霉素联合米诺环素、头孢哌酮/舒巴坦联合米诺环素、头孢哌酮/舒巴坦联合磷霉素,FIC指数分布分别为：FICI≤0.5占56.7%(17/30)、10%(3/30)、36.7%(11/30)、50%(15/30)、6.7%(2/30);0. 5＜FICI≤1占43.3%(13/30)、83.3%(25/30)、63.3%(19/30)、40%(12/30)、50%(15/30);1＜FIC＜4占0、6.7%(2/30)、0、10%(3/30)、43.3%(13/30);FIC≥4均为0。磷霉素和头孢哌酮/舒巴坦分别使联用后的亚胺培南MIC50降为单用时的1/16、1/2,MIC90降为单用时的1/8、1/2;均使联用后的米诺环素MIC50、MIC90降为单用时的1/8和1/4。结论 联合用药方案对比,头孢哌酮/舒巴坦联合米诺环素最具优势,协同作用最强,优于磷霉素联合米诺环素,但提高米诺环素抗菌活性的能力相当。头孢哌酮/舒巴坦联合亚胺培南以相加、无关效应为主,试验结果可见联用后效果逊于磷霉素联合亚胺培南,且磷霉素提高亚胺培南抗菌活性的能力更强。     

Correlation between the chemical composition and the antimicrobial properties of seven samples of essential oils of endemic Thymes in Morocco against multi-resistant bacteria and pathogenic fungi

Thymus vulgaris, Thymus satureioides, and Thymus zygis are endemic Moroccan species that are intensively used due to their extensive medications and culinary properties. To enhance and preserve these overexploited species, the effect of provenance on the chemical composition of essential oils and antimicrobial activity against human pathogens were studied. Essential oils (EO) obtained by hydrodistillation from the flowering tops of thyme species were analyzed by GC-SM. The determination of minimum inhibitory (MIC), bactericidal (MBC), and fungicide (MFC) concentrations of EO were studied by microplate microdilution. The correlation between the chemical composition of EO and antimicrobial properties were evaluated using R software. The samples studied gave variable yields, ranging from 0.70 ± 0.03% to 4.12 ± 0.21%. The main constituents of Thymus vulgaris harvested from the municipality of El Hammam are carvacrol (68.8%), γ-terpinene (11.5%), and p-cymene (3.9%), while borneol (41.3% and 31.7%) and carvacrol (14.6% and 9.8%) are the most abundant in Thymus satureioides of the communes of Tata and Tigrigra respectively. For Thymus zygis, the results revealed the dominance of carvacrol (51.7% and 57.5%) for the municipalities of Tigrigra and Ain Aghbal, thymol (47.1% and 42.1%) for the municipalities of Bensmim and Timahdite respectively. These chemical profiles have similarities, but also reveal differences from the results given in the literature. In addition, the essential oils most active towards the microorganisms evaluated were those of Thymus vulgaris, followed by Thymus zygis and Thymus satureioides. These EO have very powerful MIC (MIC ? 300 μg/ml) against Gram-negative bacteria, and in particular, concerning Enterobacters cloacae, Citrobacter koseri, and Acinetobacter baumannii. Thymus zygis EO is the most active on candidates compared to Thymus vulgaris and Thymus satureioides EO, except Candida dubliniensis which was inhibited by Thymus satureioides EO from the commune of Azrou with a MIC = 18.75 μg/ml. The correlation determined between the major components and MIC showed that phenols have the strongest positive effects on antimicrobial properties, followed by terpenes and non-aromatic alcohols. In addition, different sensitivities of pathogens to chemical families have been observed against Enterobacter cloacae, Citrobacter koseri, Candida parapsilosis, Staphylococcus aureus multiresistant, Pseudomonas aeruginosa, Acinetobacter baumannii, and Aspergillus niger. Our results support the idea that these oils could be very useful in flavoring, food preservation, as well as a source of antimicrobial agents of great power against multidrug-resistant strains.     

来氟米特对氟康唑体外抗耐药白色念珠菌增效作用研究

目的：研究来氟米特与氟康唑在体外合用对耐药白色念珠菌的抗真菌效果。方法：采用棋盘式微量稀释法测定来氟米特联合氟康唑对15株临床耐药白色念珠菌的最小抑菌浓度MIC₈₀。时间-杀菌曲线验证两药联用对耐药白色念珠菌生长的抑制作用。结果：来氟米特单药对实验所用白色念珠菌均无抗菌活性（MIC₈₀>320μg·mL^-1）。来氟米特联合氟康唑可产生协同抗菌作用,协同指数（FICI）<0.25。用药24h后,时间-杀菌曲线上联合用药组比单用氟康唑组平均降低了3.9log₁₀CFU/mL,证实两药具有协同抑菌作用。结论：来氟米特与氟康唑在体外对耐药白色念珠菌具有良好的协同抗真菌活性。     

Design and synthesis of cationic antimicrobial peptides with improved activity and selectivity against Vibrio spp

Extensive use of classical antibiotics has led to the growing emergence of many resistant strains of pathogenic bacteria. Evidence has suggested that cationic antimicrobial peptides (AMPs) are of greatest potential to represent a new class of antibiotics. The largest group of AMPs comprises peptides that fold into an amphipathic alpha-helical conformation when interacting with the target microorganism. In the current study, a series of cationic AMPs of 20 amino acids was designed and synthesised based on four structural parameters, including charge, polar angle, hydrophobicity and hydrophobic moment. The effect of these parameters on antimicrobial activity and selectivity was assessed by structural and biological analyses. Our results indicated that high hydrophobicity and amphipathicity (hydrophobic moment) were correlated with increased haemolytic activity, whilst antimicrobial activity was found to be less dependent on these factors. Three of the synthetic AMPs (GW-Q4, GW-Q6 and GW-H1) showed higher antimicrobial activity and selectivity against a broad spectrum of Gram-positive and Gram-negative bacteria compared with the naturally occurring AMPs magainin 2a and pleurocidin. This study also demonstrates that these rationally designed cationic and amphipathic helical AMPs exhibited high selectivity against several Vibrio spp. and are potential agents for future use in the treatment of these marine pathogens.     

蒲地蓝消炎口服液联合阿莫西林对肺炎链球菌感染的协同作用

目的阿莫西林(amoxicillin,Amx)具有广谱抗菌作用,蒲地蓝消炎口服液(PDL)具有抗炎、免疫调节和抗菌活性。为了增强抗菌药效、减少Amx的不良反应,本研究对二者联合应用的抗肺炎链球菌感染效果进行了研究。方法以肺炎链球菌滴鼻感染ICR小鼠建立小鼠细菌性肺炎模型;以肺指数、肺组织病理评分、炎症因子表达等作为评价指标,考察PDL和Amx联用对肺炎链球菌感染小鼠肺炎的保护作用。结果PDL液和Amx联用能显著抑制肺炎链球菌引起的小鼠肺炎病变,两药联用对感染小鼠具有协同抗感染作用,其中Amx(每日0.37 g/kg)与PDL(每日5.5 mL/kg)联用的联合指数为0.12,对肺炎的治疗表现为强协同作用,肺指数抑制率达到61.22%,肺指数显著低于模型对照组和单一药物组(P<0.05,P<0.01);Amx(每日0.37 g/kg)与PDL(每日2.75 mL/kg)联用的联合指数为0.57,为协同作用。两药联用能显著抑制感染小鼠体重下降,改善小鼠肺组织病理损伤(P<0.01),同时显著抑制细菌感染诱导的小鼠血清炎症因子白细胞介素-6(IL-6)(P<0.01)、白细胞介素-8小鼠同源物(KC)(P<0.05)、肿瘤坏死因子-α(TNF-α)(P<0.01)、单核细胞趋化蛋白-1(MCP-1)(P<0.01)的表达升高。结论PDL和Amx联用对肺炎链球菌感染小鼠肺炎具有协同治疗作用,在临床上具有重要的应用价值。     

The antimicrobial effects of selenium nanoparticle-enriched probiotics and their fermented broth against Candida albicans

Background

Lactic acid bacteria are considered important probiotics for prevention of some infections. The aim of this work was to investigate the effect of selenium dioxide on the antifungal activity of Lactobacillus plantarum and L. johnsonii against Candida albicans.

Methods

Lactobacillus plantarum and L. johnsonii cells, grown in the presence and absence of selenium dioxide, and their cell-free spent culture media were tested for antifungal activity against C. albicans ATCC 14053 by a hole-plate diffusion method and a time-kill assay.

Results

Both L. plantarum and L. johnsonii reduced selenium dioxide to cell-associated elemental selenium nanoparticles. The cell-free spent culture media, from both Lactobacillus species that had been grown with selenium dioxide for 48 h, showed enhanced antifungal activity against C. albicans. Enhanced antifungal activity of cell biomass against C. albicans was also observed in cultures grown with selenium dioxide.

Conclusions

Selenium dioxide-treated Lactobacillus spp. or their cell-free spent broth inhibited the growth of C. albicans and should be investigated for possible use in anti-Candida probiotic formulations in future.     

聚乙烯亚胺单独及与三种抗菌药物联用对白念珠菌的体外抗菌活性

目的评估多支链的阳离子高分子聚合物——聚乙烯亚胺(PEI)单独及与三种不同类别的常规抗菌药物(两性霉素B、氟康唑和多黏菌素B)联合使用对白念珠菌(MY7245和MY7238)的两种临床分离物的抗真菌活性。方法通过体外实验测定不同分子质量聚乙烯亚胺单独及与三种不同类别的常规抗菌药物联合使用对两株白念珠菌的最小抑菌浓度和杀灭时间,确定PEI单独及联合使用的体外抗真菌活性。结果分子量在2～745ku范围内的PEI均对这两种白念珠菌产生很好的抗真菌活性,且分子量小的PEI比分子量大的PEI的抗菌作用更显著。与单独作用的PEI相比,分子量较大的PEI与常规药物联合使用时可产生较强的协同作用。在体外致死研究实验中可以看到,PEI-两性霉素B和PEI-氟康唑结合物可以提高抑菌作用,但PEI-多黏菌素B结合物却拮抗抑菌作用。结论PEI单独与联合使用均对白念珠菌产生很好的抗菌效果。