Antibactericidal Activity Research Articles

Study on antibacterial active components from Viola yedoensis

Study on the antibacterial activity of Viola yedoensis and the antibacterial active compounds. The chemical compositions were isolated by means of solvent extraction, column chromatography on silica gel, sephadex LH-20 and crystallization. The antibacterial activities were tested by Neo-Sensitab disk-diffusion method, nephelometric analysis and plating method. One new compound (4) along with three known compounds were isolated from this plant for the first time and were identified as aesculetin (1), 6,7-dimethoxycoumarin (2), scopoletin (3) and 5-methoxy-7-hydroxymethylcoumarin (4), respectively. All the compounds showed antibacterial and antibactericidal activities at varying degree on Streptococcus Aureas, S. agalactiae, S. uberis, S. dysgalactiae, E. coli and Salmonella, of which 1 was most active with 0.031- 0.313 g x L(-1) of minimal inhibitory concentrations (MIC) and 0.313 - 0.625 g x L(-1) of minimal bactericidal concentrations (MBC). Viola yedoensis has a broad spectrum of antibacterial activity on animal pathogenic bacteria, and coumarins may be the main antibacterial activity ingredients.

Composite electrospun nanomembranes of fish scale collagen peptides/chito-oligosaccharides: antibacterial properties and potential for wound dressing

Purpose:The objective of the present investigation was to evaluate the antibacterial properties and the biocompatibility of composite electrospun nanofibrous membranes (NFMs) with low-molecular-weight fish scale collagen peptides (FSCP) and chito-oligosaccharide (COS), to determine their potential for use as wound dressings.Methods:Low-molecular-weight FSCP were combined with COS to prepare nanofibers by electrospinning, and polyvinyl alcohol (PVA) was used for enhancing fiber-forming ability. Transmission electron microscope and scanning electron microscope methods were used to observe bacterial adhesion and the bacterial cell membrane. Fibroblast cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Results:The best FSCP/COS mass ratio for electrospinning was 2:1, and the nanofibers had small dimensions ranging from 50 to 100 nm. The NFM showed good antibacterial activities against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The antibacterial activity against S. aureus was higher than against E. coli. The pili and adhesive fimbriae of E. coli promoted bacterial adhesion to the NFM surfaces, and S. aureus biofilms aided S. aureus adhesion on the surface of NFMs. Damage to the bacterial cell membrane indicates that the NFMs could lead to the release of intracellular materials, particularly with S. aureus. In addition, FSCP/COS NFM rapidly increased the permeability of the outer membranes of E. coli. The electrospun NFM with FSCP and COS had good biocompatibility in vitro and supported proliferation of human skin fibroblasts.Conclusion:FSCP are superior to mammalian collagen, and have feasibility and potency for wound dressings. FSCP/COS NFMs had good anti-bactericidal activity that improved with increased COS, and showed good biocompatibility in vitro and supported the proliferation of fibroblasts.

Lactoferrin-derived peptides and Lactoferricin chimera inhibit virulence factor production and biofilm formation in Pseudomonas aeruginosa

To investigate the bactericidal activity of lactoferrin-derived peptides and a new LF-derived peptides chimera (LFchimera) against P. aeruginosa and the influence on virulence factors of P. aeruginosa. Lactoferricin (LFcin) and lactoferrampin (LFampin) are highly bioactive peptides isolated from the N-terminal region of lactoferrin (LF) by pepsin digestion. In this study, we designed LFchimera containing LFcin amino acids 17-30 and LFampin amino acids 268-284. Pseudomonas aeruginosa cells were incubated in medium with peptides at different concentrations, and then the assays of viability, pyocyanin, elastase activity and biofilm formation of P. aeruginosa were performed. We found that the concentration-dependent antibactericidal activity and down-regulating pyocyanin, elastase and biofilm formation of LFchimera were significantly stronger than those of LF, LFcin, LFampin or LFcin plus LFampin. Our results indicated that LF, LFcin, LFampin and LFchimera were potential candidates to combat P. aeruginosa, and LFchimera was the most effective in them. The new LFchimera has better activity against P. aeruginosa than LF, LFcin and LFampin and may be a promising new compound for treatment of P. aeruginosa infection.

N-Chlorosuccinimide (NCS)

N-Chlorosuccinimide (NCS) is a very powerful chlorinating reagent, which also finds applications as mild oxidizing agent. This colourless, commercially available, inexpensive solid is thermally stable to some extent. It is least toxic as well as highly selective compared to chlorinating agents, such as 1,3-dichloro-5,5-dimethylhydan­toin (NDDH) and trichloroisocyanuric acid (TCCA). In the last two decades, it has emerged as a useful mediator or catalyst for many chemical reactions, such as functional groups replacement, halocyclization, formation of ­heterocyclic systems, carbon-carbon bond formation, rearrangement, deprotections, and functional group transformations. [¹] NCS also possess some bactereostatic and anti-bactericidal activity as it forms hypochlorous acid upon slow hydrolysis with water. [²] NCS is soluble in carbon tetrachloride at room temperature while its conjugate product succinimide is not, which leads to easy separation from the reaction mixture.

Anti-Nanobacterial Therapy for Prevention and Control of Periodontal Diseases

Introduction: Nanobacteria have been implicated in the formation of pathogenic calcifications e.g. kidney stones, arterial plaque, calcified cardiac valves, dental pulp stone, etc. It has been hypothesized that nanobacteria may be present in dental calculus which has a similar mineralization formation process and that nanobacteria may play an efficient role in the calcification of dental calculus. Recently nanobacteria were found in gingival crevicular fluid samples from two subjects with chronic periodontitis. The hypothesis : An anti-nanobacterial mouthwash or tooth paste containing bisphosphonates specifically etidronate and clodronate (1 mg/ml), gallium nitrate 14% (3.4% w/w gallium at 99.995% purity) and ethylenediaminetetraacetic acid (1%) with neutral pH (7.0) will may be effective for prevention of calculus formation and consequently prevention of periodontal diseases. Despite of excellent anti-nanobacterial activity of tetracycline, it is removed from the formulation. It has a wide spectrum of anti-bactericidal activity and may affect normal oral flora and cause supra-infection. Evaluation of the hypothesis: We should consider a balance be- tween negative effect of nanobacteria regarding formation of calcu- lus and periodontal diseases and positive role of nanobacteria in enamel repair and prevention of dental caries and its positive role in enamel repair and prevention of dental caries.

Chlorhexidine rinse for prevention of urethritis in men linked to oral sex

BackgroundOral sex among teenagers is on the rise. Similarity between the oral flora and organisms recovered from nongonococcal urethritis and prostatitis, points to retrograde entry of bacteria from oral cavity into the urethra following insertive oral intercourse.Presentation of the hypothesisChlorhexidine has a wide spectrum of anti-bactericidal activity encompassing gram positive and negative bacteria. It is also effective against HIV and HBV. It produced large and prolonged reductions in salivary bacterial counts within 7-h of its use. Hence, it would seem logic to postulate that rinsing with chlorhexidine before oral sex will be effective for prevention of retrograde entry of bacteria from oral cavity into the urethra. The recommendation for rinsing will be: 15 ml of a 0.12% or 10 ml of 0.2% chlorhexidine rinse for 30 seconds. Also other drug delivery systems such as chlorhexidine chewing gum or spray can be used.Testing the hypothesisMen suffering from recurrent nongonococcal urethritis or prostatitis are good subjects for testing the hypothesis. They perform genital safe sex via consistent use of condom. Yet they generally received unprotected insertive oral intercourse. Chlorhexidine can be used for prevention of recurrences of the disease.Implications of the hypothesisThe chlorhexidine will be a new, easy, attractive and effective method for reduction of nongonococcal urethritis, prostatitis and epidydimitis following insertive oral intercourse. It is poorly absorbed from skin, mucosa and gastrointestinal tract indicating systemic safety of chlorhexidine. The agent does not cause any bacterial resistance and supra-infection.

Water-stable ammonium-terminated carbosilane dendrimers as efficient antibacterial agents

A new family of amine- and ammonium-terminated carbosilane dendrimers of the type Gn-[Si(CH2)3N(Et)CH2CH2NMe2]x and Gn-{[Si(CH2)(3)N+R(Et)CH2CH2N+RMe2]x(X-)y} (where n = 1, 2 and 3; R = H, X = Cl; R = Me, X = I) respectively has been synthesized by hydrosilylation of N,N-dimethyl-N'-allyl-N'-ethyl-ethylenediamine, [(CH2=CH-CH2)(Et)N(CH2)2NMe2] with the corresponding hydride-terminated dendrimers and subsequent quaternization with HCl or MeI. Quaternized dendrimers are soluble and stable in water or other protic solvents for long time periods. The antibacterial properties of the quaternary ammonium functionalized dendrimers have been evaluated showing that they act as potent biocides in which the multivalency along with the biopermeability of the carbosilane dendritic skeleton play an important role in the antibactericidal activity of these compounds.

Plasmin Digestion of Photooxidized Milk Proteins

Plasmin-mediated hydrolysis of 6 different milk protein preparations [αS-casein (αS1 + αS2), β-casein, κ-casein, α-lactalbumin, β-lactoglobulin, and lactoferrin] was found to be very dependent on photooxidation of the said proteins. Changes in plasmin proteolysis were investigated in a peptide-mapping study applying liquid chromatography-mass spectrometry. The changes were seen in the formation of peptides formed by plasmin-mediated hydrolysis after photooxidation, which was initiated with the naturally occurring photosensitizer riboflavin in all the milk protein preparations studied. The changes in the plasmin-mediated hydrolysis of photooxidized proteins are discussed in relation to changes introduced in the protein structure upon photooxidation. Plasmin-mediated hydrolysis of αS-casein, consisting of a mixture of αS1- and αS2-casein and a preparation of β-casein, was most highly affected by photooxidation, which is in agreement with the fact that those 2 proteins have been found to be most labile toward photooxidation. Changes in the formation of potential angiotensin-I-converting enzyme-inhibitory peptides as well as peptides proposed to have antibactericidal activities by plasmin were observed by oxidation of milk proteins before plasmin-mediated hydrolysis.

New photocatalytic reactor with TiO2 coating on sintered glass cylinders

The antibiotic flumequine was used to evaluate the photocatalytic activity of TiO2 coating on sintered glass cylinders (SGC) tailored on a 0.5-l annular reactor. The cylinders were prepared with finely powdered silicate glass (150–600μm) and then coated with titania Degussa P-25 by thermal treatment. The impregnated SGC were characterized by surface techniques such as EDS, SEM and XRD. The coated cylinders present homogeneous porosity, high mechanical strength, and good light transparency. The photocatalytic activity evaluated against flumequine was found to be comparable to the photocatalytic activity presented by titania in aqueous suspension. After 20min irradiation, around 55% and 80% of 18ppm flumequine was degraded by irradiation with black light (360nm) or germicidal lamp (254nm), respectively. A high reproducibility of the activity was observed when the reaction was continually repeated using the impregnated cylinders. The antibactericidal activity of irradiated solutions was evaluated in Escherichia coli cultures showing significant inhibition.

Antibacterial activity of honey produced by honeybees (<i>Apis mellifera</i>) on bacterial species isolated from infected wound

Honey is considered to be important in traditional treatment of wound infections in many countries of the world, including Ethiopia. However, information on in vitro antibacterial activity of honey produced by honeybees on bacterial pathogens is lacking in Ethiopia. The objective of this study was to determine the antibacterial effect of honey against bacterial species isolated from wound discharges. Wound swabs and discharges were collected as part of routine clinical management of patients both from in-patient and out-patient departments of the University of Gondar Teaching Hospital. Specimens were collected and processed following standard microbiological procedures. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of honey sample on bacterial isolates were investigated by an agar dilution technique. Staphylococcus aureus was the predominant species isolated from various types of wound discharges (63%), followed by Klebsiella pneumoniea (9%), and Escherichia coli (9%). Growth retardation and complete inhibition were observed at lower concentration of 2.5% and 6% (v/v), respectively. The average MIC and MBC of honey for all tested organisms was 6.2% and 8% (v/v) of honey, respectively. Honey showed bacteriostatic and bactericidal activity on tested Gram-positive and Gramnegative isolates of bacteria from wound discharges in vitro. However, a more detailed comparative study should be made to evaluate the antibactericidal activity of honey and other antimicrobial agents currently in use. Keywords : honey, antibacterial activity, minimum inhibitory concentrations, minimum bactericidal concentrations, infected wound Ethiopian Pharmaceutical Journal Vol. 23 2005: 1-6

The Assessment of Biological Activities Associated with the Major Constituents of the Methanol Extract of ‘Wild Carrot’(Daucus carotaL.) Seeds

Daucus carota L. (Family: Apiaceae alt. Umbelliferae), commonly known as 'wild carrot' or 'Queen Anne's-lace,' is an ecologically invasive erect biennial naturalized to Scotland. The ethnobotanical uses of this species include applications in the treatment of cough, diarrhea, dysentery, cancer, malaria and tumors, and as an antiseptic, abortifacient, aphrodisiac, carminative, stimulant, stomachic and tonic. The major constituents isolated from the methanol extract of D. carota seeds by reversed-phase preparative high performance chromatography were luteolin, luteolin 3'-O-beta-D-glucopyranoside and luteolin 4'-O-beta-D-glucopyranoside, three flavones. The constituents were assessed for their antibacterial and free radical scavenging activities, as well as toxicity towards brine shrimp. Among these three flavones, luteolin showed the highest degree of free radical scavenging activity (RC50 = 4.3 x 10(-4) mg/mL) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Both luteolin and its 4'-O-glucoside demonstrated bactericidal activity against Staphylococcus aureus and Escherichia coli (Minimum Inhibitory Concentration [MIC] = 5.0 x 10(-2) - 1.0 x 10(-1) mg/mL). Luteolin also demonstrated antibactericidal activity against Bacillus cereus and Citrobacter freundii (MIC = 5.0 x 10(-2) mg/mL). Luteolin 3'-O-glucoside showed bactericidal activity against Bacillus cereus and Lactobacillus plantarum (MIC = 2.5 x 10(-1) mg/mL and 5 x 10(-1) mg/ mL, respectively). In the brine shrimp lethality assay, the LD50 value of luteolin was 5.3 x 10(-2) mg/mL, and that of its 3'-O-glucoside and 4'-O-glucoside were > 1.0 mg/mL.

Immunomodulatory Effects of Macrolides in the Lung: Lessons from In- Vitro and In-Vivo Models

Macrolide antibiotics appear to play a role in the management of diseases of chronic airway inflammation, distinctly separate from their antibactericidal activity. In the last fifteen years, their success in human clinical trials has prompted both in-vitro and in-vivo investigations to determine the mechanisms by which this family of antibiotics modulate the immune response. A large body of evidence suggests that macrolides directly target multiple components of the inflammatory cascade that occur independent of bactericidal/bacteriostatic effects. We will review the existing data in support of immunomodulatory effects of macrolides on activated leukocytes at the site of lung inflammation, on pulmonary host cells, and in animal models of lung disease.

Bismuth 2-mercaptoethanol complexes: Structural characterization, antibactericidal activity toward Helicobacter pylori, and inhibitory effect toward H. pylory-produced urease

Bismuth 2-mercaptoethanol complexes: Structural characterization, antibactericidal activity toward Helicobacter pylori, and inhibitory effect toward H. pylory-produced urease

Determination of Peroxyl Radical-Scavenging Activity in Food by Using Bactericidal Action of Alkyl Peroxyl Radical

A novel bioassay for antioxidant activity based on bactericidal actions of alkyl peroxyl radicals (ROO . ) was developed. ROO . was generated by the reaction of heme irons and various alkyl hydroperoxides. A Gram-positive bacterium, Staphylococcus aureus, was subjected to cytotoxic treatment with ROO . with or without various antioxidants. This bacterial suspension was serially diluted, on a 96-well multiplate, in mannitol broth containing phenol red as a pH indicator. After overnight incubation, the growth of ROO . -treated bacteria produces acid, resulting in a change in color of the broth, which permits easy quantitation of viable bacteria protected by antioxidants. Accordingly, ROO . scavenging by various antioxidants could be reproducibly quantitated. Among 22 antioxidants tested, cytotoxicity was substantially inhibited by α-tocopherol, glutathione, L-cysteine, probucol, butylated hydroxyanisole, and butylated hydroxytoluene. Furthermore, the antibactericidal activity of various teas and nonalcoholic drinks showed very high correlation with their antioxidant activities determined by luminol-dependent chemiluminescence assay (r = 0.91). By this simple bioassay, a large number of samples can be analyzed simultaneously to determine ROO . -scavenging activity.

Inoculum effect of new beta-lactam antibiotics on Pseudomonas aeruginosa.

The degree of the inoculum effect shown by the new beta-lactam antibiotics with Pseudomonas aeruginosa was investigated, and the antibiotics were divided into three groups based upon the observations. The group 1 antibiotics (cefotaxime, moxalactam, cefoperazone, azlocillin, piperacillin, and aztreonam) demonstrated a large inoculum effect, were poorly bactericidal, produced aberrant, elongated bacilli, and did not inhibit the increase in turbidity of high inocula during an 18-h incubation. The group 2 antibiotics (ceftazidime and ticarcillin) were slowly bactericidal, caused minimal formation of aberrant, elongated bacilli, and slowly decreased the turbidity of high inocula. The group 3 antibiotics (imipenem and gentamicin) were bactericidal, did not cause the formation of elongated bacilli, and decreased the turbidity of high inocula rapidly. Data are presented which suggest that the inoculum effect seen with the group 1 beta-lactam antibiotics is related to (i) the poor intrinsic antibactericidal activity of these antibiotics for P. aeruginosa at the inocula tested and (ii) failure of these antibiotics to inhibit the formation of aberrant and filamentous bacilli, which can result in increased bacterial mass and turbidity.

Depressant Effect of Marihuana Smoke on Antibactericidal Activity of Pulmonary Alveolar Macrophages

Other than the potentially therapeutic bronchodilatory influences of marihuana, very little is known of its biologic effects on the lung. To evaluate this problem, alveolar macrophages were harvested from rats by bronchopulmonary lavage and incubated in vitro with Staphylococcus albus and marihuana smoke of standardized 2.2-percent tetrahydrocannabinol content in graded amounts. After three hours, control alveolar macrophages inactivated 78.0 +/- 5.0 percent of the staphylococcal challenge. There was a dose-dependent depression of alveolar macrophage bactericidal activity, with 66.7 +/- 7.1 percent, 23.7 +/- 7.0 percent, 20.5 +/- 7.0 percent, and 11.4 +/- 7.6 percent of the bacteria killed following exposures to 2 ml, 4 ml, 6 ml, or 8 ml of marihuana smoke, respectively. Differential filtration of marihuana smoke revealed that the alveolar macrophage cytotoxin was present in the gas phase of the smoke and was water-soluble. Studies on purified tetrahydrocannabinol and on tetrahydrocannoabinol-extracted marihuana revealed that the impairment in alveolar macrophage function was not related to the psychomimetic or bronchodilatory components of marihuana.

An Antibactericidal Factor in the Serum of Two Patients with Infections of the Upper Urinary Tract

1. The serum of two patients with infections of the upper urinary tract contained a specific factor which inhibited its bactericidal action against the Gram-negative organism causing the infection. 2. The serum of the patients was fractionated by gel filtration and anion-exchange chromatography and pooled fractions were examined for antibactericidal activity. 3. Fractions showing antibactericidal activity appeared to contain only immunoglobulin G and it is suggested that bacterium-specific antibactericidal immunoglobulin G competes with immunoglobulin M, the major bactericidal antibody, for sites on the bacterial surface.

An antibactericidal factor in the serum of some patients with infections of the upper urinary tract.

1. The serum of two patients with infections of the upper urinary tract contained a specific factor which inhibited its bactericidal action against the Gram-negative organism causing the infection. 2. The serum of the patients was fractionated by gel filtration and anion-exchange chromatography and pooled fractions were examined for antibactericidal activity. 3. Fractions showing antibactericidal activity appeared to contain only immunoglobulin G and it is suggested that bacterium-specific antibactericidal immunoglobulin G competes with immunoglobulin M, the major bactericidal antibody, for sites on the bacterial surface.

Comparison of antibacterial activity of single and combined sulfonamides.

Conclusions1. The antibactericidal activity of various mixtures of sulfonamides is unpredictable. 2. The observed effect varies markedly with different species and with various strains of the same species of organism. 3. Depression of bactericidal potency against both gram negative and positive bacteria frequently results from combining sulfonamides. 4. The greatest and most constant decrease in antibacterial effect is produced by mixing sulfamerazine, sulfathiazole, and sulfadiazine. 5. These results suggest that combinations of sulfonamides may have little clinical usefulness in many instances, since they are often not as effective as the single agents which compose them.

A study of penicillin ointments and creams

A number of ointments and cream formulas containing penicillin were prepared and studied for their antibactericidal activity against organisms. Tests were made by a new modified agar cup-plate method which was devised in the laboratories of the School of Pharmacy at Purdue University.