Broth Macrodilution Method Research Articles

EVALUATION OF ANTIBACTERIAL RESISTANCE OF BIOFILM FORMS OF AVIAN SALMONELLA GALLINARUM TO FLUOROQUINOLONES

Antimicrobial resistance is a growing concern worldwide. The indiscriminate use of antibiotics for a period of time has led to the emergence of antibiotic resistance in pathogenic bacteria. The present study was designed to evaluate the antibacterial efficacy of fluoroquinolone drugs, ciprofloxacin, enrofloxacin, moxifloxacin, sparfloxacin, norfloxacin, pefloxacin and ofloxacin against avian Salmonella gallinarum bacterial biofilms. The study parameters, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm elimination concentration (BEC) were determined on days 1, 3, 7, 10, 14 and 20 post inoculation for the planktonic (free) and biofilm cells of S. gallinarum by macro broth dilution method. The MIC and MBC values determined on days 1, 3, 7, 10, 14 and 20 for each of the fluoroquinolone drugs against the planktonic and biofilm forms of avian S. gallinarum were found to be non-significant. BEC values determined against the biofilm forms of S. gallinarum during the study period were found to be non-significant among the tested fluoroquinolones. The results of the present study demonstrated that fluoroquinolone drugs were effective in vitro against both the planktonic and biofilm forms of avian S. gallinarum.

Development and evaluation of a broth macrodilution method to determine the biocide susceptibility of bacteria

In comparison to biocide efficacy testing, biocide susceptibility testing of bacteria so far lacks standardized methods for routine use. The aims of the present study were to develop a broth macrodilution method to test bacterial pathogens for their biocide susceptibility and to evaluate this method in an interlaboratory trial. Staphylococcus aureus ATCC®6538 was tested for its susceptibility to benzalkonium chloride, chlorhexidine and isopropanol comparing test strain suspension preparations, test volumes and incubation times. The use of 2 mL volumes for the testing and an incubation time of 24 h were proposed. Ten German laboratories participated in the interlaboratory trial. Four reference strains (S. aureus ATCC®6538, Enterococcus hirae ATCC®10541, Escherichia coli ATCC®10536 and Pseudomonas aeruginosa ATCC®15442) commonly used for biocide activity testing, were included. Strains were tested three times at independent occasions for their susceptibility to benzalkonium chloride, glutardialdehyde and isopropanol. In total, 360 data points were obtained (30 per strain/biocide combination). The modal minimal inhibitory concentration ± one dilution step was defined as acceptable range. For the four reference strains and the three biocides 80–100% of the values were considered as acceptable. The deviations within the laboratories for a strain/biocide combination were rather consistent. In general, the testing was performed without difficulties by the laboratories. Although inoculum plate counts of four laboratories were outside the acceptable range, this did not have a large impact on the results. The proposed method was stable and easy to perform. It may contribute to a harmonization and standardization of biocide susceptibility testing.

Bactericidal activity of acetone extract of Alpinia galanga on multidrug resistant clinical isolates of Enterococcus faecalis

Introduction: The objective of the study was to evaluate the inhibitory activity of five traditional Indian medicinal herbs against multidrug resistant clinical isolates of E. faecalis. Methods: Sixty five E. faecalisderived from clinical specimens were tested for their resistance pattern to 7 antibiotics by disc diffusion method. Extracts from 5 medicinal plant parts were obtained and tested for inhibitory activity against multi drug resistant clinical E. faecalisisolates. The minimum bactericidal concentration (MBC) for the active plant extract exhibiting highest activity towards the susceptible isolateswas determined by macro broth dilution method followed by sub culturing on agar plate. Results: All the clinically derived E. faecalis isolates were resistant to two or more antibiotics. Acetone extract of Alpiniagalanga inhibited 67.69% of E. faecalis and concentration of <5.0mg/ml was found to exert bactericidal activity against multi drug resistant isolates. Conclusion: Acetone extract of A. galanga exhibit bactericidal activity against multi-drug resistant clinical isolates of E. faecalis and hence could be potential phytotherapeutic candidate.

Antibacterial Efficacy of Polysaccharide Capped Silver Nanoparticles Is Not Compromised by AcrAB-TolC Efflux Pump.

Antibacterial therapy is of paramount importance in treatment of several acute and chronic infectious diseases caused by pathogens. Over the years extensive use and misuse of antimicrobial agents has led to emergence of multidrug resistant (MDR) and extensive drug resistant (XDR) pathogens. This drastic escalation in resistant phenotype has limited the efficacy of available therapeutic options. Thus, the need of the hour is to look for alternative therapeutic approaches to mitigate healthcare concerns caused due to MDR bacterial infections. Nanoparticles have gathered much attention as potential candidates for antibacterial therapy. Equipped with advantages of, wide spectrum bactericidal activity at very low dosage, inhibitor of biofilm formation and ease of permeability, nanoparticles have been considered as leading therapeutic candidates to curtail infections resulting from MDR bacteria. However, substrate non-specificity of efflux pumps, particularly those belonging to resistance nodulation division super family, have been reported to reduce efficacy of many potent antibacterial therapeutic drugs. Previously, we had reported antibacterial activity of polysaccharide-capped silver nanoparticles (AgNPs) toward MDR bacteria. We showed that AgNPs inhibits biofilm formation and alters expression of cytoskeletal proteins FtsZ and FtsA, with minimal cytotoxicity toward mammalian cells. In the present study, we report no reduction in antibacterial efficacy of silver nanoparticles in presence of AcrAB-TolC efflux pump proteins. Antibacterial tests were performed according to CLSI macrobroth dilution method, which revealed that both silver nanoparticles exhibited bactericidal activity at very low concentrations. Further, immunoblotting results indicated that both the nanoparticles modulate the transporter AcrB protein expression. However, expression of the membrane fusion protein AcrA did show a significant increase after exposure to AgNPs. Our results indicate that both silver nanoparticles are effective in eliminating MDR Enterobacter cloacae isolates and their action was not inhibited by AcrAB-TolC efflux protein expression. As such, the above nanoparticles have strong potential to be used as effective and alternate therapeutic candidates to combat MDR gram-negative Enterobacterial pathogens.

Effect of production parameters and inhibitory activity of antimicrobial compounds produced by co-cultured strains of Streptomyces xinghaiensis-OY62 and S. rimosus-OG95

Due to emergence and re-emergence of resistant pathogenic microorganisms, there is need to develop more potent antimicrobial metabolites with broad spectrum antimicrobial activity. Hence, the strains of Streptomyces xinghaiensis-OY62 (KU934248) and Streptomyces rimosus-OG95 (KU934251) were co-cultured for the production of antimicrobial metabolites using starch casein broth by submerged fermentation. Effect of production parameters on antimicrobial activity was studied using standard methods. Purification of the antimicrobial extract was carried out using column and thin layer chromatography. The Minimum Inhibitory Concentration was done by macro broth dilution method. Bioactive compounds were characterized using thin layer chromatography; Fourier transformed infraRed spectrophotometer and gas chromatography-mass spectrophotometer. The best antimicrobial activity was observed at pH 8.0, temperature of 45 °C, in starch casein broth supplemented with sodium chloride concentration of 0.6% (w/v), casein + KNO3 as nitrogen source, in the presence or absence of carbon source and a period of fifteen days of incubation. The retention factor of the partially purified antimicrobial extract was 0.97. Functional groups such as hydroxyl, aromatic rings, carboxylic acid, amides and carbonyls were detected. Eight different antimicrobial metabolites were identified and characterized. Higher quantity (41.4%) of dibutyl phthalate was produced by the co-cultured strains of the Streptomyces. The antimicrobial metabolites produced by co-cultured strains of Streptomyces xinghaiensis-OY62 and Streptomyces rimosus-OG95 exhibited broad spectrum antimicrobial activity against indicator strains. The MIC and MBC ranged between 3.12 mg/L to 6.25 mg/L and 12.5 mg/L to 25.0 mg/L respectively.

Phenotypic Antimicrobial Susceptibility Testing with Deep Learning Video Microscopy.

Timely determination of antimicrobial susceptibility for a bacterial infection enables precision prescription, shortens treatment time, and helps minimize the spread of antibiotic resistant infections. Current antimicrobial susceptibility testing (AST) methods often take several days and thus impede these clinical and health benefits. Here, we present an AST method by imaging freely moving bacterial cells in urine in real time and analyzing the videos with a deep learning algorithm. The deep learning algorithm determines if an antibiotic inhibits a bacterial cell by learning multiple phenotypic features of the cell without the need for defining and quantifying each feature. We apply the method to urinary tract infection, a common infection that affects millions of people, to determine the minimum inhibitory concentration of pathogens from human urine specimens spiked with lab strain E. coli (ATCC 43888) and an E. coli strain isolated from a clinical urine sample for different antibiotics within 30 min and validate the results with the gold standard broth macrodilution method. The deep learning video microscopy-based AST holds great potential to contribute to the solution of increasing drug-resistant infections.

Antibacterial activity study of Attacus atlas cocoon against Staphylococcus aureus and Escherichia coli with diffusion and dilution method

The aim of this study was to evaluate the antibacterial activity from Attacus atlas cocoon extract against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) with 3 diffferent solvents polar, semi-polar and non polar which was ethanol, ethyl acetate and chloroform, also to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extract. Cocoon was extracted with maceration method using 3 solvents with ratio of sample and solvent 1:10. Antibacterial activity of the Extracts obtained was evaluated with Agar disk diffusion method. The best result was then continued to determine the MIC and MBC of the extract using broth macro-dilution method. The results show that each of the extracts have antibacterial activity with broad spectrum against two different type of bacteria at concentration of 1 g/mL with different clear zone between these extracts. Clear zone from the biggest to the smallest against Escherichia coli was ethyl acetate (10.5 mm), chloroform (9 mm) and ethanol (8 mm). While against Staphylococcus aureus, was obtained by chloroform (12.5 mm), ethyl acetate (10.5 mm) and ethanol (7 mm). The MIC value of extracts can not be determine. The smallest MBC value against both bacteria was obtained by ethyl acetate with concentration of 3.125% b/v as a bactericidal.

Synthesis and Evaluation of Some Novel 2‐Amino‐4‐Aryl Thiazoles for Antitubercular Activity

A series of novel 2‐amino‐4‐aryl thiazoles were synthesized from α‐chloroacetophenone and thiourea at room temperature using acetone as solvent. The structures of synthesized compounds were confirmed by spectral data. All the compounds were evaluated for antitubercular activity by macro broth dilution method against Mycobacterium Tuberculosis H37Rv as standard strain. The synthesized compound displays notable antitubercular activity.

In vitro inhibitory effects of the ethanol extract of Tetrapleura tetraptera (Schum and thonn.) taub. against multidrug resistant staphylococcus aureus

In this study, the antibacterial effect of ethanol extract of Tetrapleura tetraptera was investigated in vitro against methicillin-resistant Staphylococcus aureus by agar diffusion and macrobroth dilution methods. At the lowest concentration of 20 mg/ml of the ethanol extract, 100 µl produced inhibition zones that ranged between 06 and 15 ± 1.0 mm while the inhibition zones ranged between 16 ± 1.0 mm and 22 ± 1.0 mm when the isolates were tested with 100 µl of the highest concentration (100 mg/ml) of ethanol extract. The minimum inhibitory concentrations (MICs) of the ethanol extract were between 0.019 mg/ml and 5.0 mg/ml while its minimum bactericidal concentrations (MBCs) ranged between 0.078 and 10.0 mg/ml. Ten strains had their MICs less than 1.0 mg/ml while the remaining S. aureus strains had their MICs at concentrations ranging between 1.25 mg/ml and 5.0 mg/ml. The degree of antibacterial activity exhibited by the extract of T. tetraptera demonstrated that its herbal medicine could be as effective as modern medicine in treating diseases associated with the test pathogenic organism and justifying its traditional use in the treatment of bacterial infections.

Antibacterial, Anti-virulence factors of Hibiscus sabdariffa extracts in Staphylococcus aureus isolated from patients with urinary tract infection

Introduction and Aim: herpalmecine have been the most interesting in therapy field of some disease, Urinary tract infection (UTI) is considered the most known bacterial diseases occurrence in healthcare and community setting for this the present study was carred out to detection antibacterial and antivrulancefactors activities of Hibiscus sabdariffa (H. sabdariffa) calyces extract against Staphylococcus aureus (S. aureus) isolated from UTI infected patients. Materials and Methods: All bacterial isolates was identified bycolonydescription, gram staining and biochemical test. Antibiotic susceptibility was tested to all the isolate. The cold and hot aqueous crude extracts was done by agar well diffusion method, MIC was found by using modified broth macro-dilution method. Results: All S.aureus isolates were completely resistant (100%) to Ampicillin, followed by Cefoxitin (91.3%) and Oxacillin (86.9 %). The isolates showed the highest sensitivity to Imipenem( 95.5%) and Clindamycin (78.2%).The percentage of resistance of S. aureus for amikacin are (39.1%).While (47.8%) and (73.9%)of isolates showedresistance to Tetracyclin and cefotaxime respectively. The result of the cold aqueous extract of H.sabdariffa calyces exhibit significant differences in their antimicrobial activities against testing bacteria in comparison with hot aqueous extract .MIC of cold aqueous extract were 25 mg/ml. The cold aqueous extract of H. sabdariffa at concentration 40mg/ml was exhibiting the best action as an inhibitor agent against S. aurous isolates. There were 8 isolates from 14 isolates lost their ability to produce protease after incubated bacteria with MIC of testing plant extract. Also the result showed that the hydrolytic and fibrinolytic activity of staphyllokiase were decreased after dealing with this extract. Conclustion: the cold aqueous extract was the best extract have antibacterial activity and effected in the production and activityof the virulence factors.

Fungal-specific Cyp51 inhibitor VT-1598 demonstrates in vitro activity against Candida and Cryptococcus species, endemic fungi, including Coccidioides species, Aspergillus species and Rhizopus arrhizus.

Invasive fungal infections, including those caused by yeasts, moulds and endemic organisms, can be significant causes of morbidity and mortality in immunocompromised hosts, those with multiple comorbidities and occasionally immunocompetent hosts. Current antifungal agents are often limited by drug toxicities, drug interactions or the development of resistance. VT-1598 is a novel tetrazole that has greater specificity for fungal Cyp51 than currently available triazoles and thus the potential for clinically significant drug interactions is reduced. We measured the in vitro activity of VT-1598 against clinical isolates of Candida and Cryptococcus species, endemic fungi, including Coccidioides, Blastomyces and Histoplasma, Aspergillus species and Rhizopus arrhizus. Antifungal susceptibility testing was performed by broth microdilution or macrodilution methods per CLSI standards. Clinical isolates of each species were used and clinically available antifungal agents were tested against each isolate. VT-1598 demonstrated in vitro activity against yeasts and moulds that was similar to or greater than that of clinically available antifungal agents, including amphotericin B, fluconazole, caspofungin, voriconazole and posaconazole. The in vitro activity of VT-1598 was also maintained against resistant isolates, including fluconazole-resistant Candida isolates. In vitro activity was also observed against endemic fungi, including Blastomyces, Histoplasma and both Coccidioides immitis and Coccidioides posadasii. VT-1598 demonstrated in vitro activity against yeasts, moulds and endemic fungi, which was maintained against isolates that had reduced susceptibility to other antifungals. Further studies are warranted to evaluate the in vivo efficacy of VT-1598 against various fungal pathogens.

Antimicrobial protection of minced pork meat with the use of Swamp Cranberry (Vaccinium oxycoccos L.) fruit and pomace extracts.

The objective of the study was to determine the antimicrobial activity of Swamp Cranberry (Vaccinium oxycoccos) fruit and pomace extracts (FSCE and PSCE) and their efficiency in minced pork meat. Ethanol (96 and 40%) and water were used for raw material extraction. Organic acids, flavonols, terpenes and stilbenes composition of the extracts was determined using HPLC. Minimal inhibitory concentration and minimum bactericidal/fungicidal concentration were determined for bacteria and fungi strains using the broth macrodilution method. The growth inhibition of Staphylococcus aureus, Listeria monocytogenes, Salmonella Enteritidis, and Escherichia coli in inoculated fresh minced pork meat containing 2.5% we-PSCE or we-FSCE (prepared by using 40% ethanol) were evaluated within 6days of refrigeration storage. Swamp Cranberry pomace extracts contained stilbenes and more organics acids and flavonols than fruit extracts. Extracts inhibited Gram-positive bacteria strains stronger than Gram-negative, regardless of used raw material. The extracts did not show antifungal activity. Water-ethanol extracts (we-FSCE and we-PSCE) had stronger antibacterial properties than ethanolic extracts (e-FSCE and e-PSCE) and aqueous extracts (w-FSCE and w-PSCE). A 2.5% addition of we-PSCE or we-FSCE to minced pork meat resulted in a reduction of the number of pathogenic cells by 4 log cycles after 4days of refrigeration storage. Baked burgers containing 2.5% of these extracts obtained high ratings for color, taste, odor, juiciness, and overall acceptability that did not differ statistically from control samples. Extracts from Swamp Cranberry constitute interesting candidates for natural preservatives of minced pork meat.

Food grade nanostructured lipid carrier for cardamom essential oil: Preparation, characterization and antimicrobial activity

Cardamom essential oil (CEO) loaded food grade nanostructured lipid carriers (NLCs) were produced using cocoa butter (as solid lipid) and Tween 80 (as surfactant) for application in aqueous-based foods. The results demonstrated that the developed NLCs had fine size (<150nm) and high entrapment efficiency (>90%). Differential scanning calorimetry (DSC) results showed a less-ordered crystalline structure leading to high loading capacity. All samples exhibited perfect type crystal (or β-modification crystal) and a less crystalline state in X-ray diffractograms. Few changes were detected in the turbidity of systems after storage time, demonstrating that the NLCs did not show significant aggregation. Antimicrobial activity of CEO emulsion and CEO loaded NLC formulations were investigated by Broth Macrodilution method and confirmed that, encapsulation was able to protect the antimicrobial activity of CEO. The results showed that CEO-loaded NLC could be used as food supplements.

Synthesis, structural investigation and antibacterial studies of non–symmetrically p–nitrobenzyl substituted benzimidazole N–heterocyclic carbene–silver(I) complexes

Several new non–symmetrically p–nitrobenzyl substituted benzimidazole–based mono–N–heterocyclic carbene (NHC)–silver(I) acetate (7a–e) and bis–NHC–silver(I) hexafluorophosphate complexes (8a–e) were synthesized by combination of 1–ethyl/1–propyl/1–butyl/1–pentyl/1–hexyl–3–(4–nitrobenzyl)benzimidazolium hexafluorophosphate salts (6a–e) with silver(I) acetate and silver(I) oxide in methanol and acetonitrile, respectively, in good yields. All the benzimidazolium hexafluorophosphate salts (6a–e) and their corresponding NHC–silver(I) complexes (7a–e and 8a–e) were structurally characterized by 1H, 13C NMR, ATR–IR spectrometry and elemental analysis. The solid–state structures of bis–NHC–silver(I) hexafluorophosphate complexes (8c) and (8e) were determined by single crystal X–ray diffraction method. Preliminary in vitro antibacterial potential of all the compounds (6a–e, 7a–e and 8a–e) were studied against six standard bacterial strains; two Gram–positive (Staphylococcus aureus and Bacillus subtilis) and four Gram–negative bacterial species (Escherichia coli, Pseudomonas aeruginosa, Shigella sonnei, and Salmonella typhi) by Kirby–Bauer’s disc diffusion method and their Minimum Inhibitory Concentration (MIC) was determined by broth macrodilution method. All the NHC–silver(I) complexes (7a–e and 8a–e) exhibited moderate to high antibacterial activities with MIC ranging between 16.0 and 128.0µg/mL, whereas benzimidazolium hexafluorophosphate salts (6a–e) demonstrated poor antibacterial potentials.

Interaction of Selected Phenylpropenes with Dipalmitoylphosphatidylcholine Membrane and Their Relevance to Antibacterial Activity.

The effect of structurally closely related phenylpropenes (PPs), estragole, anethole, eugenol, and isoeugenol, on the fluidity of dipalmitoyl phosphatidyl choline (DPPC) liposome membrane was investigated by DSC, Raman, and fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH). Liposomes were prepared by thin-film hydration method at various DPPC:PP molar ratios. The DPH anisotropy measurements of blank and PP-loaded liposomes were performed at 28, 41, and 50°C, which correspond, respectively, to gel phase, main transition temperature of DPPC, and liquid phase. The Raman images showed the formation of nano- and micrometric spherical multi-lamellar vesicles. All studied PPs exhibited a membrane fluidizing effect which was reinforced by the presence of phenolic hydroxyl group in eugenol and isoeugenol. The PPs interacted with the choline head group and the alkyl chains of DPPC membrane, wherein isoeugenol and anethole possessing the same C7-C8 position of the double bond in the propenyl side chain, incorporated deeply in the bilayer. Additionally, the PPs were analyzed for antibacterial activity against E. coli by macrobroth dilution method. Anethole and estragole were more efficient in inhibiting the bacterial growth than eugenol and isoeugenol. We conclude that the fluidizing effect of PPs on the membrane is a common mechanism that is not related to the hydrophobicity of the PP molecule. Besides, other target sites may be involved in PP antibacterial activity against Gram-negative bacteria. The greater hydrophobicity of these PPs may contribute to their penetrability through the outer bacterial membrane.

Non–symmetrically p–nitrobenzyl–substituted N–heterocyclic carbene–silver(I) complexes as metallopharmaceutical agents

In the present work, a series of eight new imidazole, 4,5–dichloroimidazole, 4,5–diphenylimidazole and benzimidazole based nitro–functionalized mono–N–heterocyclic carbene (NHC)–silver(I) acetate (7a–d) and bis–NHC–silver(I) hexafluorophosphate complexes (8a–d) were synthesised by the reaction of the corresponding azolium hexafluorophosphate salts (6a–d) with silver(I) acetate and silver(I) oxide in methanol and acetonitrile, respectively. All the synthesised compounds were fully characterized by various spectroscopic techniques and elemental analyses. Additionally, the structure of bis–(1–benzyl–3–(p–nitrobenzyl)–4,5–dichloroimidazole–2–ylidene)silver(I) hexafluorophosphate complex (8b) was confirmed by single crystal X–ray diffraction analysis. Preliminary in vitro antibacterial evaluation was conducted for all the compounds (6a–d), (7a–d), and (8a–d) by Kirby–Bauer's disc diffusion method followed by the determination of Minimum Inhibitory Concentration (MIC) from broth macrodilution method against five standard bacteria; two Gram–positive bacterial strains (Staphylococcus aureus and Bacillus subtilis) and three Gram–negative bacterial strains (Escherichia coli, Shigella sonnei, and Salmonella typhi). All the hexafluorophosphate salts (6a–d) were found inactive against the tested bacterial strains and their corresponding mono– and bis–NHC–silver(I) complexes (7a–d and 8a–d) exhibited moderate to high antibacterial activity with MIC value in the range 8–128 μg/mL. In addition, preliminary in vitro anticancer potential of all the silver(I) complexes (7a–d and 8a–d) was determined against the human derived breast adenocarcinoma cells (MCF 7) by MTT assay. All the mono– and bis–NHC–silver(I) complexes (7a–d and 8a–d) orchestrated high anticancer potential with IC50 values ranging from 10.39 to 59.56 nM. In comparison, mono– NHC–silver(I) complexes performed better than the bis–NHC–silver(I) complexes.

Antibacterial and anti-breast cancer cell line activities of Sanghuangporus sp.1 extracts

Purpose : To evaluate the activity of extracts of Sanghuangporus sp.1 fungus against pathogenic bacteria and a breast cancer cell line. Methods : The wild fruiting body and mycelium of Sanghuangporus sp.1 were extracted with water and ethanol by ultrasonication extraction. The activity of the extracts against pathogenic bacteria was determined by agar-well diffusion method while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were obtained by agar-well diffusion and broth macrodilution methods. The cytotoxicity of the extract against human breast cancer cell line MCF-7 was determined by sulforhodamine B assay. Results : Only the ethanol mycelial extract exhibited antibacterial activity. Activity was detected against 6 of the 17 test strains of bacterial pathogen. The MICs and MBCs against these 6 strains were quite low, especially for B. cereus ATCC 11778 (2.5 and 2.5 mg/mL) and S. aureus (MSSA, DMST 2933, 2.5 and 5.0 mg/mL). The ethanol mycelial extract was a more potently cytotoxic against MCF-7 cells than either the aqueous mycelial extract or the ethanol wild fruiting body extract, inhibiting cell growth at a concentration of 250 μg/mL. The aqueous wild fruiting body extract was inactive against MCF-7 cells when compared with untreated control groups. Conclusion : The ethanol mycelial extract of the medicinal mushroom Sanghuangporus sp.1, obtained by ultrasonication extraction method, exhibited potent antibacterial and anticancer activity and seems to be a substitute for wild Sanghuangporus sp. Keywords : Antibacterial activity, Anticancer activity, Sanghuangporus sp.1, Mycelial

Evaluation of Anti-fungal Activity of Coleus Species Extracts

Antifungal activity of 50%-methanol, water and absolute methanol extracts of Coleus species (whole plant) was evaluated using agar, and macro-broth dilution methods. The test microorganisms were strains of Aspergillus, Rhizopus, Mucor, Rodotorula, Geotricum, Basidiobolus, Trichophyton, Microsporum, Epidermophyton and Candida. The yields achieved with extracts were 24%, 22% and 29% for absolute methanol, water and 50% methanol extracts, respectively. The phytochemical analysis of the extracts revealed the presence of flavonoids, alkaloids, tannins, cardiac glycosides, carbohydrates, steroids, Proteins, glycosides and anthracene glycosides. All (100%) fungal strains tested were susceptible to all the extracts. The observation of the growth inhibition of the fungi tested lasted for 7-14 or more days of incubation on Sabouraud Dextrose agar plates. MIC range was 0.146-15.63mg/ml and Candida albicans was the most susceptible of the yeasts tested (MIC90 0.78mg/ml), Epidermophyton floccosum, the most susceptible dermatophyte (MIC90 = 1.56mg/ml), while T. tonsurans was the least susceptible of the fungi tested (MIC90 25mg/ml) and these results are consistent with the time kill observed with the extracts. Results authenticated the folklore medicinal usage of Coleus species for treatment of gastrointestinal, reproductive tract and skin infections.

Antibacterial Effects of Garlic Extracts and Ziziphora Essential Oil on Bacteria Associated with Peri-Implantitis.

Peri-implantitis is an inflammatory process, characterized by loss of bone around implants and bleeding on probing. Colonization of bacteria in the pocket created around the implant is one of the most important aetiologic factors involved. Although antibiotics are routinely used and are effective agents against this bacterial infection, due to the side effects and drug resistance of these medications, researchers are more interested in using herbal derivatives. There are relatively limited number of studies in this respect. To evaluate and compare the antibacterial effects of the extracts of Allium sativum and Ziziphora clinopodioides essential oil on S. aureus and P. aeruginosa. In this in vitro study conducted at Tabriz University of Medical Sciences between March 2016 and July 2016, aqueous and methanolic extracts of garlic and ziziphora essential oil were prepared and then their effects on one standard strain of P. aeruginosa and two standard strains of S. aureus and 18 clinical strains, (nine strains of P. aeruginosa and nine strains of S. aureus) which had been isolated from wound and blood cultures, were evaluated using the reference broth macro dilution method and disk diffusion technique. Data were evaluated with descriptive statistical techniques and t-test for independent groups, using SPSS 17. Aqueous and methanolic extracts of garlic did not exhibit inhibitory effects on S. aureus and P. aeruginosa. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for ziziphora essential oil against S. aureus were 0.25 and 0.5 μg/mL, respectively. The mean diameter of growth inhibition zone for S. aureus in the ziziphora essential oil group (0.25μg/mL) and Vancomycin group (10 μg/mL) were 26.09±5.8 and 14.63±1.20 mm respectively (p<0.001). Growth inhibition zone for P. aeruginosa were observed in only one (35 mm) and three cases (12.5±3.4 mm) in the ziziphora essential oil group (0.5 μg/mL) and Nalidixic acid group (10 μg/mL) respectively. The essential oil of ziziphora exhibited a favourable antibacterial effect on S. aureus; therefore, its extract can be used as an effective antimicrobial agent alone or in association with other antibiotics in the treatment of infections due to S. aureus.

English

Antimicrobial resistance is one of the greatest threats to human health. Alternatives to antimicrobials are needed to combat the rise of bacterial resistance. Essential oils (EOs) and their components are potential sources of new antimicrobials. The present study was conducted to evaluate the antibacterial and antifungal activities of two components of EOs. The antimicrobial mechanisms of eugenol and linalool were investigated against five bacterial strains and four Candida strains. Broth macrodilution method was used to compare the antibacterial and anticandidal activities of the two compounds. They exhibited antimicrobial activity against all tested strains. Germ tube formation by Candida albicans was investigated and it was found that it was completely inhibited at sub-MICs of eugenol while linalool showed minor activity compared to eugenol. Time kill kinetic studies indicated that eugenol was highly toxic to all bacterial and fungal strains within 2.5 h of exposure. Absorbance of intracellular constituents was measured at 260 nm. Only eugenol was highly effective toward lysis and cellular content leakage compared to control drugs. In addition, scanning electron microscopy (SEM) was used to charactize the effect of the two components on cell morphology and showed that both compounds induced cellular deformity of nearly all tested cells. Also, it was found that only eugenol inhibited the Beta-lactamase production and urease activity and it diminished bacterial motility of all tested bacterial strains. These results indicate that eugenol and linalool are effective antimicrobial agents and both antibacterial and antifungal activities of linalool were much weaker than that of eugenol. Key words: Antimicrobial resistance, antimicrobials, germ tube formation, time kill kinetic, cellular deformity.