Justification for the use of Ocimum gratissimum L in herbal medicine and its interaction with disc antibiotics

Background  

The ethanolic extract of the leaves of Ocimium gratisimum L. (Lamiaceae), used in traditional medicine for the treatment of several ailments such as urinary tract, wound, skin and gastrointestinal infections, was evaluated for its antibacterial properties against four clinical bacteria isolates namely: Escherichia coli, Proteus mirabilis, Staphylococcus aureus and Pseudomonas aeruginosa and the antifungal properties using a clinical isolate of Candida albicans. A typed bacterium of Escherichia coli ATCC 11775 and another typed fungal strain of Candida albicans (ATCC 90028) were also included. The study also intended to verify if the concomitant administration of conventional antibiotics with Ocimium gratisimum which is normally taken as food (spice) will negatively affect its activity.     

Electrospun polyacrylonitrile nanofibrous biomaterials

An N-halamine precursor, 3-(5'-methyl-5'-hydantoinyl)acetanilide (I), was synthesized in our laboratory and loaded onto electrospun polyacrylonitrile fiber to prepare nanosized biocidal materials, which could be rendered antimicrobial by exposure to household bleach. Differential scanning calorimetry was used to study the thermal properties of the nanofibers with and without the N-halamine precursor and its chlorinated derivative loaded. Scanning electron microscopy demonstrated that the ultrafine fibers formed with diameters from 250 to 600 nm. Chlorinated nanofibrous mats composed of the fibers were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895); they showed promising inactivation efficacies against the two bacterial species within 5 minutes of contact. Potential uses of the antimicrobial fibers include filters for industrial water and air disinfection and protective clothing.     

Determination of disk diffusion and MIC quality control guidelines for JNJ-Q2, a novel quinolone

JNJ-Q2 is a novel fluorinated 4-quinolone in development for treatment of acute bacterial skin and skin structure infection and community-acquired bacterial pneumonia. This quality control (QC) study was performed to establish ranges for control strains: Staphylococcus aureus ATCC 29213 (0.004 to 0.015 μg/ml), Enterococcus faecalis ATCC 29212 (0.015 to 0.06 μg/ml), Pseudomonas aeruginosa ATCC 27853 (0.5 to 2 μg/ml and 17 to 23 mm), Escherichia coli ATCC 25922 (0.008 to 0.03 μg/ml and 30 to 36 mm), Haemophilus influenzae ATCC 49247 (0.002 to 0.015 μg/ml and 31 to 39 mm), Streptococcus pneumoniae ATCC 49619 (0.004 to 0.015 μg/ml and 28 to 35 mm), and S. aureus ATCC 25923 (32 to 38 mm). These ranges will be crucial in evaluating JNJ-Q2 potency as it progresses through clinical trial development.     

Characterization of Antarctic psychrotrophic bacteria with antibacterial activities against terrestrial microorganisms

Five-hundreds and eighty bacterial strains, isolated from various Antarctic marine sources and locations, were screened for antimicrobial activity against terrestrial microorganisms. Twenty-two Antarctic isolates (3.8%), mainly retrieved from the water column at Terra Nova Bay (Ross Sea), expressed antagonistic activity against one to three indicator organisms. Escherichia coli and Proteus mirabilis resulted as the more susceptible, followed by Micrococcus luteus and Bacillus subtilis. None of the isolates inhibited the growth of Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella enterica and the eukaryotic fungus Candida albicans.Active Antarctic isolates, identified by 16S rDNA sequencing and phenotypically characterized by classical methods, were phylogenetically affiliated to the Actinobacteria (16 strains) and the gamma-Proteobacteria (6 strains). Inhibition patterns, as well as phenotypic characteristics, highly vary for different isolates, even though they were affiliated to the same genus or closely related to the identical microorganism retrieved from the database, suggesting that these features were more likely strain-rather than species-specific.Results obtained from the present study confirm previous observations and highlight the potentiality of Antarctic marine bacteria as novel source of antibacterial substances.     

Antibacterial activity within degradation products of biological scaffolds composed of extracellular matrix

Biological scaffolds composed of extracellular matrix (ECM) have been shown to be resistant to deliberate bacterial contamination in preclinical in vivo studies. The present study evaluated the degradation products resulting from the acid digestion of ECM scaffolds for antibacterial effects against clinical strains of Staphylococcus aureus and Escherichia coli. The ECM scaffolds were derived from porcine urinary bladder (UBM-ECM) and liver (L-ECM). These biological scaffolds were digested with acid at high temperatures, fractionated using ammonium sulfate precipitation, and tested for antibacterial activity in a standardized in vitro assay. Degradation products from both UBM-ECM and L-ECM demonstrated antibacterial activity against both S. aureus and E. coli. Specific ammonium sulfate fractions that showed antimicrobial activity varied for the 2 different ECM scaffold types. The results of this study suggest that several different low-molecular-weight peptides with antibacterial activity exist within ECM and that these peptides may help explain the resistance to bacterial infection provided by such biological scaffolds.     

An N-halamine-based rechargeable antimicrobial and biofilm controlling polyurethane

An N-halamine precursor, 5,5-dimethylhydantoin (DMH), was covalently linked to the surface of polyurethane (PU) with 1,6-hexamethylene diisocyanate (HDI) as the coupling agent. The reaction pathways were investigated using propyl isocyanate (PI) as a model compound. The results suggested that the imide and amide groups of DMH have very similar reactivities toward the isocyanate groups on PU surfaces activated with HDI. After bleach treatment the covalently bound DMH moieties were transformed into N-halamines. The new N-halamine-based PU provided potent antimicrobial effects against Staphylococcus aureus (Gram-positive bacterium), Escherichia coli (Gram-negative bacterium), methicillin-resistant Staphylococcus aureus (MRSA, drug-resistant Gram-positive bacterium), vancomycin-resistant Enterococcus faecium (VRE, drug-resistant Gram-positive bacterium), and Candida albicans (fungus), and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm controlling effects were stable for longer than 6 months under normal storage in open air. Furthermore, if the functions were lost due to prolonged use they could be recharged by another chlorination treatment. The recharging could be repeated as needed to achieve long-term protection against microbial contamination and biofilm formation.     

In vitro antibacterial activity of Omani and African honey

The study aims to investigate the antibacterial activity of honey obtained from different parts of Oman and compare it with that of honey obtained from elsewhere in Africa. A total of 24 honey samples (16 from different parts of Oman and eight from elsewhere in Africa) were investigated for their antibacterial activity against Staphylococcus aureus (NCTC 6571), Escherichia coli (NCTC 10418) and Pseudomonas aeruginosa (NCTC 10662) using standard antimicrobial assays. Marked variations in the antibacterial activity of the different honey samples were observed. Fourteen of the 16 Omani samples and five of the eight African samples showed antibacterial activity ranked as either fair, good or excellent to at least one of the three bacterial strains tested. Both Omani and African honeys possess in vitro antibacterial activity against the three bacterial strains tested, with 25% of the samples showing excellent antibacterial activity.     

Comparative behavior of E. coli and S. aureus regarding attachment to and removal from a polymeric surface

Staphylococcus aureus was found to attach more readily on polypropylene fibers with greater resistance to subsequent washing off than Escherichia coli after immersion of the fibers up to 300 s in pure culture suspensions in mineral salts medium. Each of five different washing solutions were effective against E. coli, whereas only a solution that contained SDS was effective against S. aureus. Placement of inoculated fibers on nutrient agar for longer periods of time resulted in greater resistance to washing by both organisms, although S. aureus remained more resistant than E. coli.     

人膀胱粘膜抗菌多肽的部分纯化及抗菌活性研究

以５％乙酸冲洗正常人膀胱，获得膀胱粘膜酸溶性提取物。电泳凝胶琼脂糖弥散法抗菌实验分析表明，膀胱粘膜酸溶性提取物中有一条主蛋白带（称之为ＨＢＰ）对致病性大肠杆菌ＭＬ－３５Ｐ株有抗菌活性。以超滤方法对膀胱粘膜酸溶性提取物进行分离纯化，获得分子量低于１×１０~４的超滤纯化样品，其中主要含ＨＢＰ。琼脂糖弥散法抗菌实验结果表明，超滤纯化样品对大肠杆菌ＭＬ－３５Ｐ株、绿脓杆菌ＡＴＣＣ２７８５３株、金黄色葡萄球菌ＡＴＣＣ２５９２３株及血链球菌Ｓ_３４Ｓｒ株均有很强的抗菌活性。采用Ｔｒｉｃｉｎｅ－ＳＤＳ－ｐＡＧＥ鉴定，超滤纯化样品主要显示为两条分子量分别为６．７×１０~３和８．５×１０~３的多肽。研究结果首次提示，人膀胱粘膜内存在抗菌活性很强的内源性抗生肽，是膀胱抗感染防御的主要因素。     

Effects of BCG, Corynebacterium parvum, and methanol-extration residue in the reduction of mortality from Staphylococcus aureus and Candida albicans infections in immunosuppressed mice.

An immunosuppressed mouse model was devised to test the effects of immunopotentiators on the prevention of bacterial and fungal infections. The effects of BCG and Corynebacterium were tested against Staphylococcus aureus and Candida albicans infection. The effect of methanol-extraction residue (MER-BCG) was tested against S. aureus septicemia. CDF mice were given various doses of BCG, 1.0 mg of C. parvum, or 0.5 mg of MER intraperitoneally at varying intervals before injection of an intravenous bacterial challenge. Four days before challenge, 300 mg of cyclophosphamide per ml was given intraperitoneally. BCG (106 colony-forming units) reduced mortality due to S.aureus at pretreatment intervals of 3, 7, 14, and 28 days. Isonicotinic acid hydrazide treatment elimated the protective effect of the live BCG. C. parvum was as effective as BCG against S. aureus septicemia when given 3 days before infection, but lost most of its protective effect after that time. MER protected at doses as small as 0.25 mg when given 25 days prior to challenge. Both BCG and C. parvum exerted a protective effect against Candida albicans infection.     

Antimicrobial, Wound Healing and Antioxidant Activities of Anthocephalus Cadamba

Anthocephalus cadamba (Roxb.) Miq. Syn A. chinensis (Lamk) A. Rich (Rubiaceae) is ethnomedicinally widely used in the form of paste by tribe in western Ghats for treating skin diseases. In this context, antimicrobial potential of A. cadamba against a wide range of microorganisms was studied. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing. The alchoholic and aqueous extract of this plant showed significant antibacterial and antifungal activity against almost all the organisms: Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and four fungi Candida albicans, Trichophyton rubrum—dermatophyte fungi, Aspergillus niger, Aspergillus flavus and Aspergillus nidulans—systemic fungi, with especially good activity against the dermatophyte (Trichophyton rubrum) and some infectious bacteria (Escherichia coli, Proteus mirabilis and Staphylococcus aureus) with an MIC of 2.5 µg/disc. The results show that A. cadamba extract has potent wound healing capacity as shown from the wound contraction and increased tensile strength. The results also indicated that A. cadamba extract possesses potent antioxidant activity by inhibiting lipid peroxidation and increase in the superoxide dismutase (SOD) and catalase activity.     

Towards new antibacterial drugs. Interest of para-guanidinoethylcalix[4]arene

We present here the results concerning the antibacterial properties evaluation of para-guanidinoethylcalix[4]arene, compared with its constitutive monomer, the para-guanidinoethylphenol, and hexamidine (Hexomédine), an antiseptic from the diamidine family widely used in therapeutic, chosen as a reference in this study for its resemblance in terms of functional groups. Antibacterial activities of those three compounds were evaluated by microdilution methods, in Mueller Hinton broth, onto 5 bacterial strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 & ATCC 29213 and Enterococcus faecalis ATCC 29212, according to CA-SFM and CLSI (formerly NCCLS) approved standards. In parallel, the effects of these three compounds on MRC-5 eukaryotic cell viability were evaluated with MTT assay. The results obtained here confirm a lack of activity for the monomer compound (MIC> or =512 mg/l) and a real antibacterial activity for the calixarene, comparable to hexamidine. This activity is expressed, both on Gram+and Gram- bacteria (MIC=4 mg/l for E. coli, 8 mg/l on both S. aureus strains) and at a lesser degree on E. faecalis and P. aeruginosa (MIC=32 mg/l). Similarly, both compounds, monomer and calixarene, slightly induce any modification on MRC-5 cells viability, and this until 168 h of treatment for concentrations reaching 10(-4) mol/L while hexamidine demonstrates a significant and increasing effect during the time of experiment and this for 100 to 1000 times lower concentrations. Thus, this study tends to confirm the significance of the organization of the para-guanidinoethylphenol monomer into its cyclic calixarenic tetramer for the gain of an antibacterial activity, similar to a widely used antiseptic one.     

Antibacterial and antimycotic activity of a cross-linked electrospun poly(vinyl pyrrolidone)-iodine complex and a poly(ethylene oxide)/poly(vinyl pyrrolidone)-iodine complex

Photo-cross-linked poly(vinyl pyrrolidone) (PVP) and poly(ethylene oxide)(PEO)/PVP electrospun nanofibrous mats containing complex-bound iodine have been studied. FT-IR spectroscopy analyses have proved that coordination of molecular iodine with carbonyl group and nitrogen atom of pyrrolidone rings of the PVP chains has taken place. The distribution of iodine along the fibers is uniform as revealed by X-ray mapping. The microbiological tests have demonstrated that the iodine complex-containing electrospun mats are highly effective against the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the fungus Candida albicans. Comparison with iodine complex-containing films has shown that the iodine complex-containing nanofibers exhibit a higher killing rate than the films against bacteria E. coli. SEM observations showed that PVP-iodine nanofibrous mats inhibit the adhesion of bacteria S. aureus. These characteristic features make the electrospun iodine-containing nanofibers good candidates for wound-dressing materials.     

Protective effects of S-sulfonated human gamma globulin against experimental infections in mice.

S-sulfonated gamma globulin (GGS), newly developed as a safe drug for intravenous use, was studied for its protective effects against some experimental infections in mice. Gamma globulin showed a good protective activity against infections due to Streptococcus pneumoniae and Escherichia coli and was moderately active against infections due to Staphylococcus aureus and Pseudomonas aeruginosa. In most cases, the potency of GGS was almost the same as that of original native gamma globulin. The duration of GGS activity in vivo was found to be comparable to that of native gamma globulin and much higher than that of pepsin-digested gamma globulin. In the control of infection due to E. coli, specific antibody was found to play a central role in the antibacterial action of GGS. When GGS was administered in combination with the antibiotics gentamicin and cefazolin for the control of infections due to S. pneumoniae or E. coli, a clear synergistic effect was observed.     

纳米载银磷酸锆抗菌聚氨酯的抗菌性能****

背景：聚氨酯材料具有优异的物理和化学性能,良好的生物相容性和抗凝血性能,且易加工成形,但聚氨酯制造的人工器官容易受到细菌等微生物的入侵。 目的：观察纳米载银无机抗菌剂对聚氨酯抗菌性能的影响。 方法：将纳米载银无机抗菌剂RHA-2,按0%(空白对照组),0.5%,1%,1.5%,2%,2.5%,5%比例添加到聚氨酯中。采用薄膜密着法检测抗菌聚氨酯对金黄色葡萄球菌、大肠杆菌的抑菌作用,并分析比较抗菌剂添加比例与聚氨酯抗菌性能的相关性。 结果与结论：添加纳米载银无机抗菌剂的聚氨酯对金黄色葡萄球菌、大肠杆菌具有良好的抑菌作用。抗菌剂添加比例0.5%~5%组对金黄色葡萄球菌的抑菌率分别为80.23%,91.32%,95.23%,99.19%,99.87%,99.93%,对大肠杆菌的抑菌率分别为76.70%,86.96%,92.92%,95.43%,99.34%,99.87%,显示抗菌性能随抗菌剂添加比例的上升而明显提高。表明纳米载银无机抗菌剂的添加赋予了聚氨酯优异的抗菌性能,且从抗菌角度出发,推荐纳米载银无机抗菌剂在聚氨酯中的添加比例不应低于1.5%。     

Study of the bactericidal effect of cefpodoxime using an in vitro pharmacokinetic model]

Cefpodoxime is a new oral prodrug antibiotic. Following absorption from the proximal intestine, non-specific esterases hydrolyze this cleavable ester, releasing cefpodoxime, a new broad-spectrum third-generation cephalosporin with sustained plasma levels in humans. Cefpodoxime killing kinetics were studied using an in vitro model which simulates the pharmacokinetic profile obtained in healthy volunteers given a single oral dose of cefpodoxime proxetil providing 100, 200 or 400 mg active cefpodoxime. Cefpodoxime exhibited strong antibacterial activity against tested strains of Escherichia coli, Streptococcus pneumoniae and Staphylococcus aureus. These results suggest that use of two daily doses of 100 or 200 mg each are appropriate for the treatment of E. coli and S. pneumoniae infections in view of the pharmacokinetic properties of cefpodoxime. Less intensive therapy is probably adequate in uncomplicated community-acquired urinary tract infections. The bactericidal effect of cefpodoxime against S. aureus is prolonged due to a postantibiotic effect.     

Sensitive and universal method for microbial DNA extraction from blood products.

A new method of extracting bacterial and yeast DNA from blood products dependent on guanidinium thiocyanate acid extraction and proteinase K treatment is described. In spiked samples the sensitivity per 0.1 ml of serum and blood, respectively, was 26 and 150 colony forming units (cfu) for Escherichia coli, 80 and 120 cfu for Staphylococcus aureus and 20 and 26 cfu for Candida albicans. This compared well with existing methodologies, worked on limited clinical samples and was not pathogen specific.     

新型纳米银/聚氨酯胆道支架表面抗菌涂层的体外抑菌试验

背景：胆管支架已广泛应用于胆管各种良恶性狭窄的姑息治疗,临床短期疗效显著,但长期疗效由于支架再狭窄而受到限制。 目的：研制新型纳米银/聚氨酯胆管内支架复合抗菌涂层并检测其体外抗菌性能。 方法：原位还原法用纳米银、聚氨酯制备纳米银/聚氨酯抗菌材料,采用抑菌环试验法分别测定实验组(纳米银/聚氨酯)、阳性对照(硝酸银纸片)和阴性对照(普通聚氨酯材料)3组对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌、肺炎克雷伯杆菌和肠球菌的抑菌环直径并记录分析数据。 结果与结论：纳米银/聚氨酯在体外对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌、肺炎克雷伯杆菌和肠球菌均有抑制效果,与硝酸银纸片相比,抑菌效果差异无显著性意义。结果显示纳米银/聚氨酯复合物具有良好的抗菌效果,且具有较好的稳定性。     

医用可降解锌合金材料抗菌性能及细胞相容性的体外实验研究

目的研究医用可降解锌合金材料的体外抗菌性能及细胞相容性。 方法大肠杆菌与金黄色葡萄球菌菌株分别与LB培养基混合,采用细菌比浊仪将浓度调节至1.0×10⁸CFU/mL,在二氧化碳恒温箱内37℃下培养24 h,作为细菌原液;各取相同尺寸锌合金与钛合金棒,打磨、除去表面氧化层,在100%乙醇、蒸馏水中超声波震荡洗涤,后用环氧乙烷消毒,备用。(1)大肠杆菌/金黄色葡萄球菌分别与可降解锌合金、钛合金于LB培养基中共培养,培养0、2、4、6、8、12、24、48、72 h后分别用酶标仪测定其在600 nm波长下的吸光度值。(2)将可降解锌合金、钛合金置于含金黄色葡萄球菌的固体培养平板上,培养24、48 h后观察抑菌圈大小。(3)不同浓度锌合金浸提液培养L929细胞,培养1、5 d后观察细胞形态,并用CCK8法检测细胞增殖情况,计算细胞相对增值率(RGR)。(4)将小鼠胚胎成骨细胞前体细胞(MC3T3－E1细胞)接种于可降解锌合金、钛合金表面,培养2 d后观察细胞在不同材料表面的黏附生长情况。组间数据比较采用单因素方差分析(ANOVA)及t检验。 结果不同时相点,大肠杆菌加锌合金共培养组的吸光度值明显低于单纯大肠杆菌培养组、大肠杆菌加钛合金共培养组,差异均有统计学意义(P值均小于0.05);不同时相点,金黄色葡萄球菌加锌合金共培养组吸光度值明显低于单纯金黄色葡萄球菌培养组、金黄色葡萄球菌加钛合金共培养组,差异有统计学意义(P值均小于0.05)。可降解锌合金周围出现抑菌圈,培养24 h后,锌合金圆柱体周围(4.38±0.40)mm范围内无菌落出现,培养48 h后锌合金圆柱体周围(4.75±0.44)mm范围内无菌落出现,培养24 、48 h的抑菌圈大小比较差异无统计学意义(t＝－1.10,P＝0.31),而钛合金周围未出现抑菌圈。不同浓度锌合金浸提液培养组与阴性对照组,L929细胞细胞生长状况良好,CCK8检测提示不同时相点各浸提液组细胞RGR均大于75%,细胞毒性为0～1级,细胞毒性安全性合格。MC3T3－E1细胞能黏附生长于锌合金与钛合金材料表面,细胞形态与钛合金组相比未见异常。 结论锌合金材料具有良好的抗菌性能,对大肠杆菌及金黄色葡萄球菌均有抑菌效果;具有良好的细胞相容性,细胞毒性安全性合格,细胞能在其表面黏附生长。