Macrodilution Test Research Articles

Antibacterial Activity of Crude Aqueous Extracts of Tithonia Diversifolia from Chichiri Area in Blantyre District, Malawi.

Background: The global challenge of antimicrobial resistance has spurred scientific research efforts to find alternative sources of new antibiotics. The ethnopharmacological importance of Tithonia diversifolia is well-known. Objective: The present study’s aim was to evaluate the in vitro activity of crude aqueous leaf, stem and root extracts of locally growing Tithonia diversifolia against the clinical bacterial isolates: E. coli, K. pneumoniae, and P. mirabilis. Methods: To obtain antibacterial activity data, the Broth macrodilution testing and Zone of inhibition Kirby-Bauer approaches were used. Results: Estimated diameters of zone of inhibition showed leaf extracts of Tithonia diversifolia had significantly greater antibacterial activity (19.5 ± 3.9 mm, 95% CI: 15.4 - 23.6 mm) than stem (15.2 ± 2.0 mm, 95% CI: 13.0 - 17.3 mm, p = 0.021) or root extracts (15.0 ± 2.1 mm, 95% CI: 12.8 - 17.2 mm, p=0.019). K. pneumoniae was the most susceptible isolate to growth inhibition by extracts from all plant parts. In broth macrodilution testing, leaf extracts exhibited greater potency on all study isolates compared to stem and root extracts. Conclusion: These findings support the traditional use of Tithonia diversifolia decoctions and infusions in infectious processes that are due to these pathogens and further strengthens recommendations for additional work to isolate and characterize the bioactive chemical compounds responsible for the observed antibacterial properties of the plant.

Anti-fungal Activity of 4 Herbal Mouthwashes vs. Chlorhexidine Against Candida albicans and C. glabrata: A Preliminary Study

Background: This study aimed to compare the antifungal effects of herbal mouthwashes Cinnamol and Jaftex vs. Matrica and Persica, with chlorhexidine as the gold standard, on the growth of Candida albicans and C. glabrata. Methods: Antifungal activities of the mouthwashes regarding C. albicans and C. glabrata susceptibility to antifungals were evaluated using the broth macrodilution test. The mouthwashes' minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined 3 times. The mouthwashes were compared using the Kruskal-Wallis and Dunn-Bonferroni post-hoc test. Results: Mean MICs for C. albicans in the case of chlorhexidine, Jaftex, Persica, Matrica, and Cinnamol were 0.098%, 25.0%, 10.417%, 6.25%, and 3.125%, respectively (P = 0.008, excluding chlorhexidine: P = 0.015). Mean MICs for C. glabrata in these mouthwashes (in the same order) were 0.067%, 12.50%, 5.208%, 5.208%, and 0.781 (P = 0.009, excluding chlorhexidine: P = 0.039). Mean MFCs for C. albicans were 0.26%, 100%, 12.5%, 8.333%, and 3.125% (P = 0.009, excluding chlorhexidine: P = 0.015). Mean MFCs for C. glabrata in these mouthwashes were 0.134%, 25.0%, 10.417%, 10.417%, and 1.563%, respectively (P = 0.015, excluding chlorhexidine: P = 0.039). The MIC and MFC of C. albicans and C. glabrata differed between Jaftex and chlorhexidine (P ≤ 0.024). After excluding chlorhexidine, the MIC or MFC of Jaftex and Cinnamol differed (P ≤ 0.030). Conclusions: All the mouthwashes showed antifungal activity against C. albicans and C. glabrata. Among them, the newly introduced Cinnamol mouthwash exhibited the best antifungal activity against C. albicans and C. glabrata, while the experimental herbal mouthwash (Jaftex) was the weakest. Chlorhexidine showed the most potent anti-Candida effect compared to herbal mouthwashes.

Antimicrobial effect of Pentaclethra Macroloba plant extract against Enterococcus Faecalis.

This study evaluated the antimicrobial efficacy of a new intracanal drug based on Pentaclethra macroloba extract, a plant of Amazonian origin, against Enterococcus faecalis using macrodilution test and intratubular evaluation with Confocal Laser Scanning Microscopy (CLSM). The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the pure extract of Pentaclethra macroloba andits association with calcium hydroxide and ultracall were determined. Then, thirty-three dentin cylinders were prepared and inoculated with E. faecalis, to evaluate the antimicrobial effect of the medications on the dentinal tubules with CLSM. The data was analyzed using the Kruskal-Wallis and Dunn tests. The extract in association with calcium hydroxide showed a lower CBM, and in the intratubular test all tested medications were effective against E. faecalis (P >0.05). The new intracanal drug based on P. macroloba extract has an antimicrobial effect against E. faecalis and further studies are needed for its clinical use.

Antimicrobial activity of various extracts of Sargassum glaucescens on the antibiotic resistant organisms

The antimicrobial activity of brown alga methanol, ethyl acetate, hexane, and chloroform extracts on bacteria Gram positive, Gram negative, and fungi was evaluated by using nutrient broth macrodilution test. Sargassum glaucescense was collected around the coastal area of Chabahar (south of Iran) protected marine area of the Oman sea in April and May 2015. Six pathogenic organisms including; Enterococcus faecium ATCC 51299, Streptococcus mutans ATCC 35668, Shigella boydii ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883, Salmonella enteritidi PTCC, 1709, Candida albicans ATCC 10231 and Aspergillus fumigatus PTCC 5009 were investigated by the broth dilution method. Methanolic Extract for six strains showed good activity amongst eight strains. Hexane extract, after methanolic extract has good effect on antimicrobial activity against five strains. All bacteria strain in this survey has showed resistance against ethyl acetate and chloroformic extracts. S. glaucescens using four various solution extract against eight different human pathogens showed an important antimicrobial and antifungal activity. However, more investigation has to be done on separation, purification and detection of the active ingredients in order to recognize their antifungal and antifungal activity.

Antimicrobial activity and biocompatibility of slow-release hyaluronic acid-antibiotic conjugated particles.

Here, the aim was to design and use a long-lasting antibiotic release system for prevention of postoperative infections in ophthalmic surgery. Ciprofloxacin and vancomycin-conjugated hyaluronic acid (HA) particles were prepared as drug carriers for sustained release of antibiotics. The antimicrobial effects of the released drugs were determined by disc-diffusion and macro-dilution tests at different times up to 2weeks. Slow degradable HA particles were obtained with 35.2wt% degradation within 21days. The drug loading amount was increased by employing two sequential chemical linking (conjugation, 2C) and one physical absorption loading (A) procedures (2C+A processes) from 148±8 to 355±11mg/g HA particles for vancomycin. The amounts of vancomycin and ciprofloxacin that were released linearly was estimated as 64.35±7.35 and 25.00±0.68mg/g, respectively, from drug-conjugated HA particles in 100h. Antimicrobial studies revealed that antibiotic-conjugated HA particles could inhibit the growth of microorganisms from 1h to 1week. The MBC values were measured as 0.25, 4.0, and 0.25mg/mL against Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis, respectively, after 72h incubation time. Cytotoxicity studies showed no difference between fibroblast growth or corneal thickness after 5days with or without HA-antibiotic particles. The drug release studies and antimicrobial activity of antibiotic-loaded HA particles with time against various bacteria further revealed that HA particles are very effective in preventing bacterial infections. Likewise, cytotoxicity studies suggest that these particles pose no toxicity to eukaryotic cells, including corneal endothelium.

An alternative disk diffusion test in broth and macrodilution method for colistin susceptibility in Enterobacteriales

Colistin and polymyxin B are old drugs that have been reintroduced to treat Gram-negative infections lacking other treatment options; however, colistin resistance have been reported. To know the correct susceptibility pattern is mandatory for multidrug resistant bacteria. Broth microdilution method is the gold standard to evaluate colistin and polymyxin B susceptibility; nevertheless, it is time consuming and needs expertise to be performed. Disk diffusion method on Müeller-Hinton agar is no longer recommended to evaluate polymyxins susceptibility. In this study we evaluated two methods (disk diffusion in broth and broth macrodilution) as alternative options to identify polymyxin resistance in an easy way. A total of 536 Enterobacteriales isolates were assessed for colistin susceptibility. All non-wild type Enterobacteriales (41) were chosen and 31 wild type bacteria were randomly selected, were used to perform disk diffusion tests in broth and for broth macrodilution tests. We found 100% of concordance between both tested methods and broth microdilution.In conclusion, these two methods are reliable and easier options that complement as initial screening susceptibility for colistin in Enterobacteriales in microbiology laboratories lacking personnel and infrastructure to perform broth microdilution method.

Functionalization of halloysite nanotubes with polyethyleneimine and various ionic liquid forms with antimicrobial activity

ABSTRACTHalloysite nanotube (HNT), a natural clay, was modified with branched polyethyleneimine (PEI) to form PEI‐HNT using epichlorohydrin (ECH) as coupling agent, then protonated with HCl to obtain H‐PEI‐HNTs providing [NH3]+[Cl]− functionality for potential antimicrobial properties. Upon PEI modification, zeta potential value of HNTs was increased to +37.3 mV from −34.5 mV and to +41.1 mV for H‐PEI‐HNTs. Only 1.87 wt % H‐element in HNT was increased to 3.03 wt % upon PEI modification along with newly generated elements of N and C at 2.99 and 9.93 wt %, respectively. Moreover, ionic liquid (IL) forms of HNTs with [NH3]+[N(CN)2]−, [NH3]+[PF6]− and [NH3]+[BF4]− functionality were generated via anion exchange of H‐PEI‐HNTs with sodium dicyanamide (SDC), ammonium hexafluorophosphate (AHFP), and sodium tetrafluoroborate (STFB). The antimicrobial properties of the modified, protonated, and IL forms of HNTs were determined via macro dilution, diffusion and agar screening tests against Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538 strains, and Candida albicans ATCC 10231 strains. It was found that H‐PEI‐HNTs possesses potent antimicrobial effect compared with the other forms of HNTs with 2–4 mg mL−1 MIC and 8–16 mg mL−1 MBC values via the macro dilution method. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48352.

Identification of Luteolin in Henna (Lawsonia inermis) Oil, a Persion Medicine Product, by HPTLC and Evaluating Its Antimicrobial Effects

Background and objectivesPersian scholars such as Avicenna and Zakariya al-Razi have pointed out many uses for henna oil. The present study aimed to propose a method for standardization of this oil.MethodsThe luteolin content has been evaluated quantitively by HPTLC method to standardize the henna oil. The oil sample was applied on silicagel plate and the bands were developed using CHCl3-MeOH (95:5). The plate was scanned at λ 254 nm. The minimum inhibitory concentration was determined through the broth macrodilution test to examine the antibacterial activity of the oil.ResultsThe retention factor of the sample zone of luteolin standard was 0.6±0.01. The concentration of luteolin in henna oil was 56.57±0.66 μg/mL. MICof Henna oil against Gardnerella vaginalis and Neisseria gonorrhoeae was 87 μg/mL and against Streptococcus was 870 μg/mL.ConclusionAccording to the results of this study, henna oil contains the luteolin. Further studies are needed to identify other henna oil compounds and their effects. Gardnerella vaginalis, N. gonorrhoeae, Group B streptococcus are among the pathogenic agents of cervicitis. The application of henna oil for treatment of uterus diseases in Persian medicine can be justified given the antimicrobial effects of henna oil on these three species of bacteria.

Antioxidant activity of essential oils from condiment plants and their effect on lactic cultures and pathogenic bacteria

ABSTRACT: Studies about preservative and antioxidant activity of essential oils have been encouraged in recent years, given their importance to food industry. The aim of the current study was to evaluate the antioxidant properties and antimicrobial activity of essential oils deriving from Syzygium aromaticum, Cymbopogon citratus and Lippia alba against lactic and pathogenic bacteria responsible for food-borne diseases. Essential oil antibacterial activity was assessed through disc diffusion and macrodilution tests conducted in a mixed lactic culture of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus (YF-L903) and of Escherichia coli (ATCC 8739), Staphylococcus aureus (ATCC 6538), Salmonella enterica (ATCC 6017) strains. Based on the chromatographic analysis results, the essential oils shown to be composed of eugenol (79.41%) which was the prevalent compound in S. aromaticum, geranial (31.89%), neral (24.52%) and β-myrcene (25.37%) in C. citratus, as well as of geranial (33.80%) and neral (25.63%) in L. alba. The observed antibacterial activity confirmed the dose-dependent effect of these three oils on all the assessed bacteria; there was halo inhibition at concentration 20μL mL-1. The essential oil of S. aromaticum presented better antioxidant activity, with IC50 equal to 5.76μg mL-1 and antioxidant activity index of 6.94, and it was considered strong (AAI>2.0) in comparison to the other evaluated oils. This essential oil also presented excellent antioxidant activity at concentrations lower than the one required to inhibit lactic cultures. Based in this outcome, the essential oil from S. aromaticum can be used as preservative agent in processed food whose formulation presents lactic cultures.

Antibacterial activity evaluation of selected essential oils in liquid and vapor phase on respiratory tract pathogens

BackgroundThe increasing number of multidrug-resistant bacteria and the fact of antibiotic resistance is leading to a continuous need for discovering alternative treatments against infections, e.g. in the case of respiratory tract diseases. Essential oils (EOs), because of their volatility, can easily reach both the upper and lower parts of the respiratory tract via inhalation. Therefore, the aim of the present study was the antibacterial evaluation of clove, cinnamon bark, eucalyptus, thyme, scots pine, peppermint, and citronella EOs against respiratory tract pathogens such as Streptococcus pneumoniae, S. mutans, S. pyogenes, Haemophilus influenzae, H. parainfluenzae, and Moraxella catarrhalis. Furthermore, we wanted to compare the antibacterial effect of these EOs in two different test systems to provide data for the development of an appropriate product formulation.MethodsMinimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with in vitro vapor phase test (VPT) and broth macrodilution test (BDT). The chemical and percentage compositions of the EOs were determined by GC-MS and GC-FID analysis.ResultsAmong the EOs, thyme was the most effective against S. mutans (MIC: 0.04 mg/mL in BDT, but cinnamon bark and clove oils also presented high inhibition in liquid medium with MIC values of 0.06 mg/mL and 0.1 mg/mL against S. pneumoniae and S. pyogenes, respectively. M. catarrhalis was the most sensitive to thyme EO (MIC: 0.09 mg/mL). Cinnamon bark EO was the most effective against Haemophilus spp. (MIC: 0.06 mg/mL). In the VPT, cinnamon bark was the most effective oil against all investigated pathogens with MIC values in the range of 15.62–90 μl/L. Surprisingly, the eucalyptus and scots pine showed weak activity against the test bacteria in both test systems.ConclusionsThe EO of thyme, clove and cinnamon bark may provide promising antibacterial activity against respiratory tract pathogens either in liquid medium or in vapor phase. However, their effect is lower than that of the reference antibiotics. The combination of EOs and antibiotics may be beneficial in the alternative treatment of respiratory tract diseases. In vivo studies are necessary to calculate the effective dose of EOs in patients and determine their possible side effects and toxicity.

Antibacterial action of Tropical honey on various bacteria obtained from diabetic foot ulcer

The purpose of study was to evaluate the antibacterial action of Indian honey on bacteria obtained from diabetic foot ulcer. Time kill assay was performed with varying concentration of honey. Broth macro dilution test was used to determine MIC and MB

Antimicrobial and antibiofilm activities of nanoemulsions containing Eucalyptus globulus oil against Pseudomonas aeruginosa and Candida spp.

Candida species are the main responsible microorganisms for causing fungal infections worldwide, and Candida albicans is most frequently associated with infectious processes. Pseudomonas aeruginosa is a gram-negative bacterium commonly found in immunocompromised patients. The infection persistence caused by these microorganisms is often related to antimicrobial resistance and biofilm formation. In this context, the objective of the present study was to prepare and characterize nanoemulsions containing Eucalyptus globulus oil and to verify its antimicrobial and antibiofilm activities against P. aeruginosa and Candida spp. The nanoemulsions had a size of approximately 76 nm, a polydispersity index of 0.22, a zeta potential of – 9,42 mV and a pH of approximately 5.0. The E. globulus oil was characterized by gas chromatography, being possible to observe its main components, such as 1-8-Cineol (75.8%), p- Cymene (7.5%), α-Pinene (7.4%) and Limonene (6.4%). The antimicrobial activity of the nanoemulsion was determined from the macrodilution tests and the cell viability curve, where the minimum fungicidal concentration of 0.7 mg/mL for C. albicans and 1.4 mg/mL for C. tropicalis and C. glabrata were obtained. However, the nanoemulsions did not present antimicrobial activity against P. aeruginosa, since it contains only 5% of the oil, being ineffective for this microorganism. The nanoencapsulated oil action against the formed biofilm was evaluated by atomic force microscopy and calcofluor staining, and the nanoemulsion was more efficient for two of the three Candida species when compared to free oil.

Study of the Antifungal Activity of Shikonin and Alcoholic – Oily Extracts of Iranian Arnebia euchroma L

Introduction: Today regarding drug resistance of fungi and bacteria, many researches are focused on herbal-based medication. As these herbal-based medications can show better adaptivity, the minimum advantage of them compared to synthetic drugs is that they are harmless. This article aimed to study the antifungal effect of alcoholic extract and essence of Arnebia euchroma L (Abukhalsa) roots on saprophytic and dermatophytic fungi. Methods: In this research, the roots were collected from Zagros heights in spring. Then they were dried and 300 mL ethanol was added to each 100 g dried powder. The alcoholic extraction was performed by maceration and the extract was concentrated by distillation in vacuum. The clevenger apparatus was used to extract the essence; then it was extracted by boiling water at vacuum for 4–6 hours. Shikonin was provided in commercial form. The antifungal activities of alcoholic extract, essence and Shikonin were studied and recorded using cylinder test based on the diameter of inhibition zone in Sabouraud-Dextrose agar. Minimum inhibitory concentration (MIC) and Minimum fungicidal concentration (MFC) were measured by broths macrodilution tests. Results: The results from cylinder, MIC and MFC tests showed that 30% of shikonin was more effective than root on fungi. Our data demonstrated that alcoholic extract was better than oily extract. Conclusion: The alcoholic extract had better characteristics than the essence. To confirm the final findings, further researches are required.

A Clostridium difficile Lineage Endemic to Costa Rican Hospitals Is Multidrug Resistant by Acquisition of Chromosomal Mutations and Novel Mobile Genetic Elements.

The antimicrobial resistance (AMR) rates and levels recorded for Clostridium difficile are on the rise. This study reports the nature, levels, diversity, and genomic context of the antimicrobial resistance of human C. difficile isolates of the NAPCR1/RT012/ST54 genotype, which caused an outbreak in 2009 and is endemic in Costa Rican hospitals. To this end, we determined the susceptibilities of 38 NAPCR1 isolates to 10 antibiotics from seven classes using Etests or macrodilution tests and examined 31 NAPCR1 whole-genome sequences to identify single nucleotide polymorphisms (SNPs) and genes that could explain the resistance phenotypes observed. The NAPCR1 isolates were multidrug resistant (MDR) and commonly exhibited very high resistance levels. By sequencing their genomes, we showed that they possessed resistance-associated SNPs in gyrA and rpoB and carried eight to nine acquired antimicrobial resistance (AMR) genes. Most of these genes were located on known or novel mobile genetic elements shared by isolates recovered at different hospitals and at different time points. Metronidazole and vancomycin remain the first-line treatment options for these isolates. Overall, the NAPCR1 lineage showed an enhanced ability to acquire AMR genes through lateral gene transfer. On the basis of this finding, we recommend further vigilance and the adoption of improved control measures to limit the dissemination of this lineage and the emergence of more C. difficile MDR strains.

Comparative Evaluation of Antifungal Activity of Piper Betel Leaf Oil, Origanum vulgare Essential Oil and Fluconazole Suspension on Candida albicans − An In Vitro Study

Introduction: Oropharyngeal candidiasis is an opportunistic mucosal infection caused by Candida albicans. It usually responds to topical treatments such as clotrimazole troches, topical fluconazole, chlorhexidine mouthwash and nystatin suspension. Piper betel leaf oil and Origanum vulgare essential oil have shown some topical antifungal activity. Aim: To determine and compare the antifungal efficacy of piper betel leaf oil, O. vulgare essential oil and fluconazole suspension against C. albicans. Materials and Methods: The zone of inhibition was measured by the cup–plate diffusion method using 100 μl volume of piper betel leaf oil, O. vulgare essential oil and fluconazole suspension, which were pipetted into the wells of the inoculated Sabouraud’s dextrose agar plates. The zone of inhibition was measured in millimetres using Vernier calliper. Minimum inhibitory concentration (MIC) was determined by the broth macro-dilution test by pouring 1 ml of the respective concentrations of the test material to the individual test tubes along with 10 μl of the diluted test organism inoculum. Finally, MIC was calculated using a reflective viewer. Results: The zone of inhibition for O. vulgare essential oil (>40 mm) was more than fluconazole suspension (>35 mm). MIC of O. vulgare essential oil, piper betel leaf oil and fluconazole suspension was 1.6%, 0.4% and 0.8%, respectively. Conclusion: O. vulgare essential oil was found to be a more effective antifungal agent than piper betel leaf oil and fluconazole suspension.

Synthesis and in vitro antifungal activity of isoniazid-derived hydrazones against Coccidioides posadasii

Coccidioidomycosis is a potentially severe infection caused by dimorphic fungi Coccidioides immitis and Coccidioides posadasii. Although guidelines are well established, refractory disease is a matter of concern in the clinical management of coccidioidomycosis. In the present study three isoniazid-derived hydrazones N′-[(E)-1-(4-methoxyphenyl)ethylidene]pyridine-4-carbohydrazide, N′-[(E)-1-(4-methylphenyl)ethylidene]pyridine-4-carbohydrazide, and N′-[(E)-1-(phenyl)ethylidene]pyridine-4-carbohydrazide were synthesized and evaluated for antifungal activity against C. posadasii. Susceptibility assays were performed by macrodilution testing. Interactions between the hydrazones and amphotericin B or itraconazole were evaluated by the checkerboard method. We also investigated the impairment of such compounds on cell ergosterol and membrane integrity. The synthesized molecules were able to inhibit C. posadasii in vitro with MIC values that ranged from 25 to 400 μg/mL. Drug interactions between synthesized molecules and amphotericin B proved synergistic for the majority of tested isolates; regarding itraconazole, synergism was observed only when strains were tested against N′-[(E)-1-(phenyl)ethylidene]pyridine-4-carbohydrazide. Reduction of cellular ergosterol was observed when strains were challenged with the hydrazones alone or combined with antifungals. Only N′-[(E)-1-(4-methylphenyl)ethylidene]pyridine-4-carbohydrazide altered membrane permeability of C. posadasii cells. Isoniazid-derived hydrazones were able to inhibit C. posadasii cells causing reduction of ergosterol content and alterations in the permeability of cell membrane. This study confirms the antifungal potential of hydrazones against pathogenic fungi.

Chemical Composition and in Vitro Antibacterial Activity of Native Men‌tha longifolia Essential Oil from Ardabil, Iran on Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus

Background: Most of the population in the different areas of world is affected by bacterial infections responsible for dental caries. Due to the importance of traditional medicines derived from herbs used for dental problems, this study investigated in vitro antibacterial activity of Mentha longifolia essential oil from Ardabil, Iran, on Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus, bacteria that cause tooth decay. Materials and Methods: The volatile oil of Mentha longifolia leaves was extracted by hydrodistilla tion method using a Clevenger-type apparatus and analyzed by GC and GC/MS system.The antibacterial activity was evaluated by the disk diffusion susceptibility in dilutions of 62.5, 125, 250, 500, 1000 and 2000�� g/�� l and broth macrodilution test methods. Results: The oil was particularly rich in Pulegone (31.78%), 1,8-cineole (15.99%), menthoforan (11.25%), cis-isopulegon (10.5%) and paramenth-3-n-8-l (6.85%). The medicinal plant essential oil could prevent the growth of the bacteria, and the rates of MIC and MBC of native pennyroyal essential oil on Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus were 110, 165, 80, 120, 450 and 650�� g/�� l, respectively. The maximum inhibition zone diameter was about 12.2, 27.2 and 4.8 mm, for Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus respectively, at the concentration of 500��J�� l -1 . Conclusion: In this work, the essential oil of medicinal plant containing effective ingredients could prevent the growth of bacteria and may be used as an affordable and available source for medicinal purposes.

Potencialização da ação do hidróxido de cálcio sobre o Enterococcus faecalis pelo inibidor da bomba de prótons omeprazol

Purpose: Calcium hydroxide is not fully effective against Enterococcus faecalis (E. faecalis), a facultative anaerobic bacterium proven to be resistant to most conventional disinfection processes. The aim of this in vitro study was to evaluate the effect of calcium hydroxide, omeprazole and the association of these substances against Enterococcus faecalis, as well as to evaluate if the acidcatalysation of the omeprazole had any influence in the results. Methods: The Minimum Inhibitory Concentration (MIC) of these drugs against E. faecalis (ATCC 29212) was determined using macrodilution test adapted from the CLSI (Clinical Laboratory and Standards Institute). Solutions with different concentrations of calcium hydroxide, associated or not to omeprazole, were tested. Data were statistically analyzed using ANOVA test with Tukey post-hoc, with a level of significance of 5%. Results: The MIC to calcium hydroxide was 32 mg mL-1 and, when associated with omeprazole, this was reduced reduced to 16 mg mL-1. The omeprazole and acidified omeprazole had similar activity. Conclusions: Omeprazole potentiated the effect of calcium hydroxide, since the association of these drugs reduced the MIC for E. faecalis. The acidification of omeprazole, when associated with calcium hydroxide in different concentrations, did not influence its effect.

Anti-uropathogenic activity, drug likeness, physicochemical and molecular docking assessment of (E-)-N′-(substituted-benzylidene)-2-(quinolin-8-yloxy) acetohydrazide

ObjectiveTo deal with the anti-uropathogenic and in silico screening of (E-)-N′-(substituted-benzylidene)-2-(quinolin-8-yloxy)acetohydrazide analogues in order to search the potential anti-uropathogenic agents. MethodsThree (E-)-N′-(substituted-benzylidene)-2-(quinolin-8-yloxy)acetohydrazide analogues were synthesized. Structure elucidation was done using various spectroscopic techniques including infrared radiation, 1hydrogen-nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, etc. Physicochemical score, bioactivity score and molecular docking studies were carried out using Lipinski's rule of five, Molinspiration (web based software), Autodock 4.2 tools. In vitro anti-uropathogenic activity was carried out against four pathogens named as Staphylococcus aureus (S. aureus), Staphylococcus epidermidis, Proteus mirabilis and Escherichia coli by disc diffusion method and macro-dilution test following their morphological and biochemical characterization. ResultsThe formation of (E-)-N′-(substituted-benzylidene)-2-(quinolin-8-yloxy)acetohydrazide is confirmed from the spectroscopic results. All the compounds were found in compliance with Lipinski's rule of five and exhibited bioactivity score from −0.50 to 0.00. Docking results revealed that compound-1 is forming one hydrogen bond with TYR 576 and two hydrogen bond with GLU 569, while compound-2 is forming one hydrogen bond with ARG 599, and compound-3 forming 0 hydrogen bond. The anti-uropathogenic evaluation exhibited that compound one exhibited better activity against S. aureus, while it was found to possess moderate to good activity against both Gram-positive bacteria and Gram-negative bacteria excluding S. aureus. ConclusionsOur study revealed that compound one exhibited better activity than the standard in case of S. aureus and moderate to good activity against rest of the pathogens. Molecular docking, physicochemical and bioactivity studies strongly supported the experimental results. From the well obtained results it was concluded that compound-1 can lead as potential anti-uropathogenic agents.

Characterization, activity, and computer modeling of a molecular inclusion complex containing rifaldazine

BackgroundThe purpose of this study was to develop, characterize, and investigate a molecular inclusion complex containing rifaldazine with good solubility and antibacterial activity.MethodsRifaldazine, a lipophilic molecule, was encapsulated into the hydrophobic cavity of β-cyclodextrin to form a molecular inclusion complex (RAABCD) with good solubility. RAABCD was prepared in a short time using a solid-state grinding method. The inclusion ratio, binding constant, and change in Gibbs free energy were determined by a phase solubility diagram and/or ultraviolet-visible spectroscopy. Differential scanning calorimetry and Fourier transform infrared spectroscopy of RAABCD were performed. Morphological features of RAABCD were observed by photomicroscopy. The most likely optimal configuration for RAABCD was simulated by computer modeling. Broth macrodilution testing was done to investigate the antibacterial activity of RAABCD.ResultsThe inclusion ratio, binding constant, and change in Gibbs free energy, determined by a phase solubility diagram and/or ultraviolet-visible spectroscopy were 1:1, 288.33/261.33 L/mol, and 32.29/31.73 kJ/mol, respectively. Differential scanning calorimetry and Fourier transformed infrared spectra of RAABCD confirmed the molecular interaction between rifaldazine and β-cyclodextrin. The morphological difference between irregular and amorphous-shaped RAABCD and columnar-shaped rifaldazine further confirmed the molecular encapsulation of rifaldazine. The most likely optimal configuration for RAABCD was confirmed by computer modeling. Broth macrodilution testing indicated that RAABCD had good antibacterial activity.ConclusionRAABCD had improved solubility and good activity, and might be a promising alternative for treatment of a range of bacterial infections.