Widest Zone Of Inhibition Research Articles

The anti- Leishmaniasis activity of Purified Bacteriocin Staphylococcin and Pyocin Isolated from Staphylococcus aureus and Pseudomonas aeruginosa

Tropical illnesses caused by parasites proceed to cause socioeconomic devastation that reverberate worldwide protozoan parasites, like Leishmania. This parasite has an enormous public health problem in many countries. There is a growing requisite for new control methods for many of these illnesses due to the increasing drug resistance showed by the parasites and problems with drug poisonousness. In this study, fifty-five patients (burns and wounds) were collected from patients from Al-Yarmouk Hospital and Teaching Baghdad Hospital during the period from November, 2015 to January, 2016. Cultural and morphological characteristic examination, biochemical tests were conducted and confirmed the diagnosis by antibiotics sensitivity test and Vitek-2 system. The results identified thirty-three Staphylococcus aureus and thirty Pseudomonas aeruginosa from skin burn and wounds. Vitek 2 system gave confirmation of positive results for both strains with a probability 98-99%. The S. aureus isolate (S3) and P. aeruginosa (P 5) was chosen among bacterial isolates as a good producer for crude both bacteriocins according to their widest inhibition zone by well diffusion assay WDA. Two steps method extraction were used for bacteriocin purification, first via ammonium sulphate at 70% and next step by Sephadex G-50 gel filtration chromatography. The two new drugs staphylococcin and pyocin at different concentrations was used for the treatment of L. tropica and L. donvani . All concentration of Staphylococcin showed no inhibitory activity on promastigotes of L. tropica and L. donvani . While the concentration of 32.5 µgmL -1 of pyocin showed the maximum cytotoxic effect on promastigotes of L. tropica and L. donovani, where the inhibition rate (IR%) were 87.1% and 87.9% respectively. As part of the research objectives is the discovery of new treatments against leishmaniasis also benefit from improved models.

Effect of water Clove Extract on Streptococci and Mutans Streptococci, in Comparison to Chlorhexidine Gluconate (A Comparative In Vitro and In Vivo Study)

Recently, in many parts of the world there is a rich tradition in the use of natural products for the treatments of many infectious diseases; many herbal remedies have been used because of their antibacterial, anti- inflammatory, cytostatic, antifungal and antiviral. Stimulated saliva was collected from four healthy looking females aged (20-21) from which mutans streptococci were isolated. Sensitivities of mutans streptococci according to Agar Well Technique showed that water clove extract was effective in the inhibition of these bacteria, mutans streptococci were more sensitive to chlorhexidine compared to water extract as indicated by the wider zones of inhibition on the Mueller Hinton Agar. An in vitro experiment was conducted to evaluate the effect of these agents on acid formation by mutans streptococci, the result showed that chlorhexidine gluconate and water clove extract were effective in retardation of acid formation. The study involved one in vivo experiment to test the effect of water clove extract (10%) against salivary streptococci and mutans streptococci in comparison to 0.2% chlorhexidine and deionized water. Stimulated saliva was collected from 18 volunteers aged (24-27 years) they were divided into three groups each group rinsed once with either chlorhexidine, deionized water or clove water extract for one minute. The counts of bacteria were recorded at different time points (one minute prior to the rinse, 30 minutes after rinsing, one hour and two hours). No significant difference in the counts of streptococci was found between deionized water and water clove extract for all time points, rinsing with any one of these agents resulted in a slight decreased in the counts of these bacteria, chlorhexidine showed a sharp reduction in the counts of bacteria which was highly significant (P<0.001). For mutans streptococci, a highly significant differences were found between the three mouth rinses (P<0.001) in the counts of bacteria in the following time points (after thirty minute, after one hour). Within these times chlorhexidine was shown to be the most effective in reducing the counts of these bacteria followed by water clove extract. The result of the present study showed the effectiveness of clove especially against mutans streptococci, although it was less than chlorhexidine, but it can be use as effective anticaries agent. This study aimed to evaluate the effect of different concentrations of water clove extract in comparison to chlorhexidine gluconate 0.2% and deionized water on growth, acidogenicity of mutans streptococci in vitro and viability counts of streptococci and mutans streptococci among a number of volunteers.

Comparative Evaluation of Antimicrobial Efficacy of Platelet-rich Plasma, Platelet-rich Fibrin, and Injectable Platelet-rich Fibrin on the Standard Strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.

Context:Platelet concentrates are commonly used to promote periodontal soft- and hard-tissue regeneration. Recently, their antimicrobial efficacy is also explored. Various platelet concentrates have evolved which differ in the centrifugation protocols. Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa) have been found to have an important role in periodontal pathology.Aims:In this study, PRP, PRF, and I-PRF are compared for their antibacterial effect against Pg and Aa.Materials and Methods:Blood samples were obtained from ten systemically and periodontally healthy individuals. Platelet concentrates were prepared using standardized centrifugation protocol. Antimicrobial activity was examined on standard strains of Pg and Aa using well diffusion method.Statistical Analysis Used:Means for the width of zones of inhibition were calculated along with standard deviations, and the comparison was made using Wilcoxon signed-rank test.Results:In case of Pg, I-PRF had the widest zone of inhibition which was significantly wider as compared to PRF. Furthermore, PRP had significantly wider zone of inhibition against PRF. In case of Aa, PRP had wider zone of inhibition which was significantly wider as compared to that of PRF and I-PRF.Conclusions:All the three platelet concentrates PRP, PRF, and I-PRF have antibacterial activity, but PRP and I-PRF are more active as compared to PRF. I-PRF being autologous and easy to prepare can be a very useful adjunct to the surgical therapy in bringing down the bacterial count helping in wound healing and regeneration.

Effect of Extraction Solvents on Bioactive Compounds and Antimicrobial Activities of Two Varieties Garcinia kola (heckel) OBOWO 02 (soft and less bitter) and OBOWO 03 (Hard and Very Bitter)

The aim of this study was to compare the effectiveness of the extracts obtained using the different solvents - water, acetone, methanol and ethanol on the phytochemicals and antimicrobial activity of Garcinia kola.(Obowo 20 and 03) The following 4 bacterial isolates were used for the investigation of the antimicrobialactivities and and the minimum inhibitory concentration (MIC) of the extracts. The phytochemical analysis of each of the extract indicated the presence of tannin, saponin, flavonoid, Hydrogen cyanide (HCN), alkaloid, carotenoid, anthocyanin and phenol. The extracts exhibited significant inhibitory action against S. aureus, S. typhi, P. aeruginosaand E. coli. The result revealed that methanol extract exerted the highest significant activities (P> 0.05) against all the tested organisms at the various treatment regimes with S. aureus having a wider zone of inhibition followed by E. coli, P. aeruginosa and S. typhiwith the lowest inhibitory zones. The MIC of the methanol extract against the organisms was 12.5, 12.5, 25 and 50 mg/ml respectively. The aqueous extract showed the least significant activity against S. aureus, E. coli, P. aeruginosa and S. typhi with MICs of 25, 25, 25 and 50mg/ml respectively.

Microemulsion Based Bioadhesive Gel of Itraconazole Using Tamarind Gum: In-vitro and Ex-vivo Evaluation

The current study was aimed to formulate and evaluate bioadhesive gel containing microemulsion (ME) of itraconazole (ITZ) and an attempt was made to investigate suitability of tamarind gum (TG) as a gelling agent. The solubility of ITZ in oils, surfactants and co-surfactant was evaluated for the selection of appropriate component. The ratio of surfactant and co-surfactant was optimized by constructing pseudoternary phase diagram. Ternary phase diagram was constructed using isopropyl myristate (IPM) and oleic acid (OA) as oil phase, tween 80 as surfactant and isopropyl alcohol (IPA) as cosurfactant in order to obtain ME region. The optimized ME of ITZ was characterized by its qualitative and quantitative tests and incorporated into polymeric gels of carbopol (CBP), xanthan gum (XG) and TG. The ME based ITZ gels were evaluated for pH, drug content, viscosity, ex-vivo bioadhesion, spreadability and in vitro drug release. Furthermore, antifungal activity of the gels was performed by agar cup diffusion technique using cultures of Candida albicans. ITZ showed maximum solubility in mixture of IPM and OA (1:1). Stable ME was obtained when IPM and OA was taken in the ratio of 1:1 as oil phase, Tween 80 as surfactant and isopropyl alcohol (IPA) as cosurfactant at the weight ratio of 10:45:45. The optimized ME based gels showed pH in the range of 6.11 to 6.48, spreadability in the range of 4.1 to 7.1gm.cm/sec and ex vivo bioadhesion in the range of 65 to 84gm. The viscosity study indicated pseudoplastic behaviour of all ME based gel formulations. Amongst the studied ME gels, TG containing gels exhibited fast and complete drug release at the end of 24h. Formulation F7 containing TG showed wide zone of inhibition and found to be stable for three months. These results indicate that the TG containing ME gel may be a used as vehicle for topical delivery of drugs.

<i>In vitro</i> evaluation of the antibacterial activity of some medicinal plant extracts against <i>Xanthomonas campestris pv. musacearum</i>

Enset bacterial wilt caused by Xanthomonas campestris pv. musacearum (Xcm) is a destructive disease of Ensete ventricosum (Welw.) Cheesman) in Ethiopia. The antibacterial activities of methanol leaf extracts of Achyranthes aspera, Agarista salicifolia, Datura stramonium, Melia azedarach, Pycnostachys abyssinica and Vernonia amygdalina were evaluated in vitro against Xcm. Fresh leaves were collected, dried under shade and ground to fine powder. Extraction was carried out using maceration method. The antibacterial activity of extracts was evaluated by disc diffusion method. Total phenolics content was estimated using Folin Ciocalteau method. The result revealed that higher percent extract yield was obtained from A. salicifolia followed by P. abyssinica . Extracts of all species showed antibacterial activity except M. azedarach . Significant differences in inhibition zone diameter were recorded between species and among test concentrations. The widest inhibition zone was recorded by A. salicifolia followed by P. abyssinica . Unlike others, extract of A. salicifolia had abundant amount of alkaloids, flavonoids, phenols, terpenoids, saponnins, tannins and cardiac glycosides. The remaining species lacked one or more of these metabolites and the existing ones occurred either in small or moderate amount. Moreover, the extract of A. salicifolia was found to have the highest total phenolics content and this was positively correlated with inhibition zone diameter at all test concentrations suggesting its potential antibacterial activity. This shows that the extract of A. salicifolia has the potential for further bioformulation and commercialization as biocide with broad spectrum activity. However, further research should be conducted to identify the active compounds responsible for such antibacterial activity. Keywords: Ensete ventricosum; Agarista salicifolia, Pycnostachys abyssinica, Inhibition zone;Total phenolics

Good Bugs vs Bad Bugs: Evaluation of Inhibitory Effect of Selected Probiotics against Enterococcus faecalis.

The main goal of endodontics is the prevention of apical periodontitis. This is due to the presence of persistent pathogenic microorganisms, such as Enterococcus faecalis, and its ability to directly cause acute and chronic inflammation in the periapical tissues. Lactobacillus has been shown to promote health in the intestines as well as to inhibit the growth of certain problematic oral bacteria. This study explores shifting the established paradigm of endodontic treatment, which has focused on eliminating all bacteria from the canal system and on elimination of the problematic bacteria through introducing probiotics. A preliminary work was performed to evaluate the possible effectiveness of probiotics in preventing the growth of E. faecalis. Two probiotic cultures Lactobacillus plantarum ATCC 8041 and Lactobacillus rhamnosus ATCC 7408 were selected to check their antimicrobial activity against E. faecalis ATCC 29212 by two methods: agar cup/well diffusion method and deferred antagonism test. Agar cup method: A total of 0.5 mL of requisite test pathogen culture was inoculated into 20 mL of molten sterile Mueller and Hinton agar and cooled to 45 ± 2°C. Circular wells of diameter 10 mm were punched in each of the poured plates. Appropriately diluted test samples were added to the above-punched wells. The plates were incubated upright position at 37°C for 24 hours in aerobic conditions. Postincubation, zone of inhibition was measured. The cell-free supernatant of Lactobacillus species was also evaluated for antimicrobial activity. Deferred antagonism test: The test probiotic strain was standardized to 0.1 optical density (OD) at 600 nm and inoculated in a 1 cm wide diametric streak across the surface of trypticase soy agar + yeast extract + calcium carbonate (TSYCa) agar using a sterile cotton swab. Then, the plate agar containing the test strain was incubated at 37°C for 24 hours under aero-philic condition and then standardized to 0.1 OD at 600 nm for overnight (18 hours, 37°C). A purified culture of indicator strain (pathogen) was streaked at right angles to the line of original producer growth. Postincubation plates were observed for the inhibition zone width of the indicator strain. Under the conditions of this study, Lactobacilli had an inhibitory effect on the growth of E. faecalis by agar cup method but not by deferred antagonism test. This pilot study demonstrated that probiotics show a potential in root canal therapy. If probioitcs are effective against end-odontic pathogens, they can be potentially used as intracanal medicaments. This will be a novel concept of introducing bac-teriotherapy in endodontics and replacing pathogenic bacteria by healthy bacteria, normal flora.

Ag-Enhanced Antibacterial Property of MgO Film

MgO and silver-containing MgO (AgMgO, 3.3, 9.1 at% Ag) films were sol-gel coated on titanium to improve its antibacterial property. Thermal analyses of MgAc2·4H2O powder revealed that MgO was crystallized at 400 °C. X-ray diffraction analysis showed that MgO was converted to Mg(OH)2 or Mg5(CO3)4(OH)2·4H2O during the ageing in air. Silver nanoparticles at the surface of AgMgO films were identified by scanning electron microscopy and x-ray photoelectron spectroscopy. The MgO film was about 1.5 um thick. The potentiodynamic polarization test in the Ca-free Hank’s balanced salt solution showed that the coated titanium samples had better corrosion resistance than the polished one. The dissolution of silver nanoparticles resulted in a current peak in the polarization plots. In the antibacterial test against E. Coli, the inhibition zone width was 0.3, 1.6, 2.0 mm for the films with 0, 3.3, 9.1 at% Ag, respectively. The bactericidal mechanisms of the MgO and AgMgO films were discussed. The present work would provide a facile method for antibacterial surface modification of titanium based osteo-implants.

Antibacterial and Antifungal Activities of Micromeria biflora (Leaves).


 Background: Herbal medicines have been practiced for thousands of centuries by tribes all over the world. We aim to study extraction, fractionation, antibacterial and antifungal activity of micromeriabiflora.
 Methodology: Sample was washed properly with de-ionized water, solvents used (i.e. chloroform, ethyl acetate, n-hexane and methanol) were filtered and added. Some amounts of dehydrated reagents to purify the solvents before using. Shad dried plant powder was chopped and soaked in methanol for 10 days Dimethyl sulfoxide(DMSO) was used as solvent because it did not show any activity against bacteria and also it possess polar and non-polar groups therefore, in dimethyl sulfoxide most of the polar and non-polar compounds are soluble. The antibacterial bioassay was done by Agar Well Diffusion method, by measuring the zone of inhibition against the test microorganisms. Two fungal strains i.e. Alternaria, Fusariumoxysporium were used for antifungal activities.
 Results: At 5mg/mm the detailed spectrum of antibacterial activity of various fraction i.e. n-hexane, chloroform, ethyl acetate, and methanol was determined. All fractions showed activity against fungal species. Highest activity was shown by Chloroform fraction against Fusariumoxysporium giving wider zone of 10.2 (mm). Ethyl acetate fraction against Alternaria was very less active giving lowest value of 5.9 (mm).
 Conclusion: The results of antibacterial activity revealed that methanol show highest activity among all fractions against salmonella typhi. The methanol extract of Micromeriabiflora gave the widest zone of inhibition (16.1mm) against salmonella typhi using agar well diffusion. The results therefore established a good support for the use of Micromeriabiflora in traditional medicine.

Radical Scavenging, Antimicrobial and Insecticidal Efficacy of <i>Parmotrema cristiferum</i> and <i>Dirinaria applanata</i>

Lichens are self-supporting symbiotic association of mycobiont and photobiont. The present study was conducted to investigate antimicrobial, insecticidal and radical scavenging potential of methanol extract of two macrolichens viz . Parmotrema cristiferum (Taylor) Hale and Dirinaria applanata (Fee) D.D. Awasthi. Antibacterial activity was tested against a panel of 5 bacteria by Agar well diffusion assay. Minimum inhibitory concentration was determined against 2 bacteria by broth dilution method. Antifungal efficacy was determined against 5 molds by Poisoned food technique. Free radical scavenging activity was screened by DPPH radical scavenging assay. Total phenolic content was estimated by Folin-Ciocalteau reagent method. Insecticidal activity was determined against 2nd instar larvae of Aedes aegypti Among lichen extracts, D . applanata exhibited stronger inhibition of bacteria as evidenced by wider zones of inhibition and low MIC values. Extract of D . applanata suppressed the mycelial growth of test fungi to higher extent when compared to extract of P . cristiferum The scavenging of DPPH radicals was also marked in case of D. applanta when compared to P. cristiferum . The content of total phenolics was also higher in D. applanata than that of P. cristiferum . Lichen extracts showed concentration dependent larvicidal effect. D. applanata exhibited stronger larvicidal effect than P. cristiferum . Overall, D. applanata displayed marked bioactivities when compared to P. cristiferum . This could be mainly due to high phenolic content. The macrolichens of this study appear to be promising sources of bioactive agents.

Characterization and Antibacterial Activity of a Glycoside Antibiotic from <i>Streptomyces variabilis</i> PO-178

In the present study, characterization and antibacterial activity of a glycoside antibiotic from fermentation broth of bioactive Streptomyces variabilis PO-178 recovered previously from Western Ghat soil of Agumbe, Karnataka, India was investigated. Mass cultivation of the strain PO-178 was carried out in Starch casein nitrate broth. The fermentation broth was extracted using butanol solvent in a separation funnel. The concentrated butanol extract was subjected to chromatographic techniques viz., thin layer and silica gel column chromatography for purification of bioactive components. Out of 3 fractions (A, B and C) obtained, only one fraction (C) displayed inhibitory activity against Staphylococcus aureus and Pseudomonas aeruginosa. The bioactive fraction C was subjected to spectral analysis (LC-MS, IR, 1 H-NMR and 13 C-NMR) in order to determine the structure. On the basis result of spectral analysis, the purified fraction was predicted as a glycoside antibiotic with molecular weight 514 and molecular formula C 24 H 34 O 12 . The antibiotic displayed marked inhibitory activity against S. aureus as revealed by wider zones of inhibition and low minimum inhibitory concentration value.

The in-Vitro Antibacterial Effect of Three Selected Plant Extracts against Staphylococcus aureus and Streptococcus agalactiae Isolated from Bovine Mastitis

The present study was conducted from November 2013 to April 2014 in Addis Ababa University, College of Veterinary Medicine and Agriculture, Debre Zeit, Ethiopia on the in-vitro antibacterial activities of the steam bark of Combretum molle, the leaves of Xanthium strumarium and FR1 against Staphylococcus aureus and Streptococcus agalactiae isolated from bovine clinical mastitis. The in-vitro antimicrobial test was found with encouraging results against the test bacteria. Among the plant preparations which were tested the Mean Zone of Inhibition (MZI) of Xanthium strumarium was found with the widest zone of inhibition when compared with the other two with Mean Zone of Inhibition (mm) of 20.5, 18.5, 16, 15.25, and 13 to the 10%, 5%, 2.5%, 1.25%, and 0.625% concentrations, respectively against Staphylococcus aureus. The Mean Zone of Inhibition (mm) of FR1 was found to be 23.25, 21.25, 18.75, 16.5 and 13.75 to the 10 %, 5%, 2.5%, 1.25%, and 0.625% concentrations, respectively, which was the widest MZI when compared with the other two plant extracts of similar concentrations against Streptococcus agalactiae. The plant extracts were found with dose dependent inhibition zone against both bacterial isolates. The 10% preparations of the plant extracts were comparable with the standard antimicrobial used (Gentamicin) as positive control which show better zone of inhibition than Tetracycline. The result of the present study is indicative that these herbal preparations might be considered as an alternative option for the treatment of resistant isolates of clinical bovine mastitis after studying their safety of margin in-vivo.

An In-vitro Evaluation of the Effect of Anti-candidal Herb (Olive) on Streptococcus Mutans

Aim: The aim was to evaluate the antimicrobial effect of olive extracts on Streptococcus mutans in in-vitro conditions. Materials and Methods: An in-vitro experimental study was conducted in a laboratory setting. Ethanolic extract of olive was prepared separately by cold maceration technique. The extract was then diluted with an inert solvent, dimethylformamide, to obtain five different concentrations (2%, 4%, 6%, 8%, and 10%) of each. 0.2% chlorhexidine was used as a positive control and dimethylformamide was used as a negative control. The different extracts, along with controls, were then subjected to microbiological investigation to determine, which gave a wider zone of inhibition against S. mutans. The zone of inhibition was measured in millimeters. Results: Olive extract presented the largest zone of inhibition of 33 mm at the concentration of 8%. Conclusion: Ethanolic extract of olive demonstrated antimicrobial activity against S. mutans.

Antimicrobial activity of Triphala on Lactobacilli and Candida albicans: An in vitro study

Aim: To determine whether Triphala (Terminalia bellerica, Terminalia chebula, Emblica officinalis) extract has an antimicrobial activity against Lactobacilli and Candida albicans. Materials and Methods: Ethanolic extract of Triphala was prepared by using the cold extraction method. The extract was diluted with an inert solvent, dimethylformamide, to obtain 15 different concentrations of the extract. 0.2% chlorhexidine was used as a positive control and dimethylformamide was used as a negative control. The extract, along with the controls, was subjected to microbiological investigation to determine which concentration among the 15 different concentrations of the extract gave a wider inhibition zone against Lactobacilli and C. albicans. The zones of inhibition were measured in millimeters using a Vernier caliper. Results and Conclusions: Triphala extract demonstrated antimicrobial property against Lactobacilli and C. albicans with maximum zone of inhibition of 22 mm at 6% and 20 mm at 9%.

Identification of bacterial strain ge15 and its controlling effect on ginseng diseases

Based on previous results of 16S rDNA sequence homologuous and results of physic-biochemical indexes and morphological characteristics in the present work, bacterial strain ge15 isolated from roots of ginseng plants was identified as Stenotrophomonas rhizophila. Confronting incubation results showed that, strain ge15 inhibited the growth of Alternaria panax, Phytophthora cactorum, and Cylindrocapon destructans significantly, and the width of inhibition zone was 13.3, 24.0, 12.0 mm, respectively. Further results showed that the emergence rate and seedling survive rate of ge15 treatment was significantly higher than those of the control, and which was similar to pesticide carbendazol treatment. The ge15 strain has good application potential in ginseng diseases control without contamination.

Antibacterial, antioxidant, antifungal and anti-inflammatory activities of crude extract from Nitraria schoberi fruits.

This study is the first comprehensive investigation of the antibacterial, antioxidant, antifungal and anti-inflammatory activities of a crude extract from Nitraria schoberi L. (Zygophyllaceae) fruits. The extract was tested against four Gram-negative (Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella pneumoniae and Acinetobacter lwoffii) and one Gram-positive (Staphylococcus aureus) bacteria using the agar disc diffusion and microdilution methods. P. aeruginosa was inhibited the most (widest inhibition zone) while K. pneumonia showed the largest MIC value. The antioxidant activity of fruits (0.02 mg/mL vs. 0.04, 0.06 and 1.00 mg/mL for α-tocopherol, butylated hydroxyanisole and ascorbic acid, respectively) was determined by the paired diene method. The antifungal activity of N. schoberi fruits was tested against different fungi, including Aspergillus niger and Candida albicans, with 300 µg/mL of fruit extract being the most effective concentration. The percentage of anti-inflammatory activity assayed for N. schoberi fruit extract at 100, 200 and 500 µg/mL was 36.12, 59.89 and 88.33 %, respectively. N. schoberi fruits possess potent antibacterial, antioxidant, antifungal and anti-inflammatory properties, and may be used as an antibacterial and antifungal to treat diseases and/or as a protective agent against disorders associated with oxidative stress and inflammation.

The effectiveness of novel bacteriocin derived from Escherichia coli colonized in the fermented pineapple Ananas comosus (L.) Merr. against pathogenic bacteria isolated from aquaculture sites

Aim: The aim was to evaluate antimicrobial property of bacteriocin isolated from Escherichia coli against pathogenic bacteria from aquaculture sites. Materials and Methods: E. coli was isolated from fermented pineapple Ananas comosus using eosin methylene blue agar. The antimicrobial activity of the isolated E. coli was screened using hole-plate diffusion method. The bacterial strain that showed the widest inhibition zone was selected and grown in tryptic soy broth, followed by partial purification of bacteriocin by using ammonium sulphate. Bacteriocin derived from the E. coli was subjected to the antimicrobial test against 55 bacteria strains namely Aeromonas hydrophila (n=10), Citrobacter freundii (n=5), Edwardsiella tarda (n=10), Flavobacterium spp. (n=10), Pseudomonas spp. (n=10), Vibrio parahaemolyticus (n=5) and Vibrio alginolyticus (n=5) by using twofold broth microdilution method to determine minimum inhibitory concentration (MIC) values of the bacteriocin against the tested bacteria. Results: The results of the present study showed that the MIC values of the partially purified bacteriocin against present pathogenic bacteria isolates ranged from 7.81 to 31.25 ppm whereas the MIC values of kanamycin (positive control) ranged from 15.63 to 125 ppm. Conclusion: The results of the present study showed the bacteriocin derived from E. coli can control all the present bacterial isolates indicating the huge potential of the bacteriocin as a new antimicrobial agent for aquaculture uses.

A Quantitative Determination of the Antibacterial Efficiency of Fibrous Air Filters Based on the Disc Diffusion Method

In this study, we fabricated air filters coated with Ag nanoparticles and evaluated their antibacterial efficiencies using colony counting method (CCM) and disc diffusion method (DDM) as a function of Ag nanoparticle content. Two kinds of bacterium Escherichia coli (Gram-negative bacterium), and Staphylococcus epidermidis (Gram-positive bacterium) were tested. As the amount of antibacterial agent increased, the inhibition zone width (IZW), which is the result of DDM, gradually increased and reached the maximum value, while the number of colony forming unit (CFU), which is the result of CCM, decreased and became zero. We derived a correlation equation using the CCM and DDM results, which was used to define the quantitative antibacterial efficiency of the filters according to DDM results.

Assessment of Antimicrobial Activity of Various Concentrations of Commercially Available Tulsi (Ocimum Sanctum) Powder against Streptococcus Mutans

Aim: To assess the antimicrobial activity of various concentrations of Tulsi (Ocimum sanctum) extract, obtained from commercially available Tulsi powder, against Streptococcus mutans. Setting and design: Experimental design, in vitro study, Lab setting. Materials and methods: Ethanolic extract of Tulsi was prepared by the cold extraction method. The extract was then diluted with an inert solvent, dimethyl formamide, to obtain 7 different concentrations (2%, 3%, 4%, 5%, 6%, 7% and 8%). 0.2% chlorhexidine was used as a positive control and dimethyl formamide was used as a negative control. The extract, along with the controls, was then subjected to microbiological investigation to determine which concentration among the 7 different concentrations of the extract gave a wider inhibition zone against Streptococcus mutans. The zones of inhibition were measured in millimetres using a vernier caliper. Results: At the 6% concentration of Tulsi extract, a zone of inhibition of 27 millimetres (mm) was obtained at a volume of 50 µl. This was the widest zone of inhibition observed among all the 7 different concentrations of Tulsi that were investigated. Conclusion: Tulsi extract demonstrated an antimicrobial property against Streptococcus mutans and can be used as a mouthwash. This could be further confirmed by in-vivo studies.

Effect of the Woven Proportions and Structures on the Bacterial Activity of the Silver-Plated/ Photocatalyst Fabric

The study is to weave the yarns of silver-plated fiber and photocatalyst fiber together to make 18 kinds of fabrics with different woven proportions and structures, and conduct antibacterial experiments on the fabrics with agar diffusion plate method. The experimental results show that for the strains of E.coli and Staphylococcus aureus, with the increasing woven proportion of silver-plated fiber and photocatalyst fiber, the width of inhibition zone grows; and in the condition of the same woven proportion of the two fibers, the plain weave fabric has the best antibacterial activity. And overall considering the antibacterial activity, cost and safety of the fabric, the plain weave fabric with 12.5% distribution ratio of silver-plated fiber is the optimal antibacterial fabric among the 18 samples.