Showing papers on "Antibacterial activity published in 1993"

Antibacterial Activity ofLactoferrin andaPepsin-Derived Lactoferrin Peptide Fragment

Abstract: ([3H]LPS) fromthree bacterial strains, Escherichia coli CL9 1-2,SalnoneUa typhimurium SL696, andSalmonelUa montevideo SL5222. Undermostconditions, moreLPSisreleased bythepeptide fragment thanbywhole bovine lactoferrin. Inthepresence ofeither lactoferrin orlactoferricin there isincreased killing ofE.coli CL9 1-2by lysozyme. Likehumanlactoferrin, bovine lactoferrin andlactoferricin havetheability tobindtofree intrinsically labeled [3H]LPS molecules. Inaddition tothese effects, whereas bovine lactoferrin wasatmostbacteriostatic, lactoferricin demonstrated consistent bactericidal activity against gram-negative bacteria. This bactericidal effect ismodulated bythecations Ca2+, Mg2+,andFe3+butisindependent oftheosmolarity ofthemedium. Transmission electron microscopy ofbacterial cells exposed tolactoferricin showtheimmediate development of electron-dense "membrane blisters." These experiments offer evidence that bovine lactoferrin andlactoferricin damage theouter membrane ofgram-negative bacteria. Moreover, thepeptide fragment lactoferricin hasdirect bactericidal activity. Aslactoferrin isexposed toproteolytic factors invivo which could cleave thelactoferricin fragment, theeffects ofthis peptide areofbothmechanistic andphysiologic relevance.

Novel polycationic biocides: Synthesis and antibacterial activity of polymeric phosphonium salts

Abstract: Various polymeric phosphonium salts and the corresponding low-molecular-weight model compounds were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. Antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds, particularly against S. aureus. Furthermore, the polymeric phosphonium salt exhibited a higher activity by 2 orders of magnitude than the polymeric quaternary ammonium salt with the same structure except the cationic part

Polymeric phosphonium salts as a novel class of cationic biocides. II. Effects of counter anion and molecular weight on antibacterial activity of polymeric phosphonium salts

Abstract: Various poly[tributyl(4-vinylbenzyl)phosphonium salt]s with different counter anions were prepared and their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. Antibacterial activity was found to be affected by the structure of the counter anions. The activity was low for a counter anion which tends to form a tight ion-pair with phosphonium ion, while it was high for those facilitating ionic dissociation to free ions. Furthermore, the molecular weight dependence of the antibacterial activity was investigated for poly[tributyl(4-vinylbenzyl) phosphonium chloride] with various molecular weights against S. aureus. Antibacterial activity was found to increase with molecular weight. Various copolymers were prepared in which the compositional ratio of tributyl(4-vinylbenzyl)phosphonium chloride to acrylamide, N-vinyl-2-pyrrolidone, or styrene was altered, and the effect of the positive charge density on the antibacterial activity was investigated against S. aureus. Antibacterial activity of the copolymers was much higher than that of the low-molecular-weight model compound and enhanced with the molar fraction of the phosphonium units in the copolymers. © 1993 John Wiley & Sons, Inc.

Antibacterial activity of multilayer silver–copper surface films on catheter material

Abstract: The antimicrobial activity of Ag, Cu, and layered Ag–Cu surface films, sputter-coated onto several types of catheter material, against clinical isolates of Staphylococcus epidermidis and Staphyloco...

Structure-function studies of amphiphilic antibacterial peptides

Abstract: The synthesis of 11 peptides, ranging in composition from 9 to 17 amino acid residues, by solid-phase methodology was accomplished with the purpose of studying how the amphiphilic and hydrophobic character, the size of the molecule, and the charge distribution modulate the antibacterial activity. It was found that peptides composed of 16 and 17 amino acid residues, with high hydrophobic (mainly due to Trp or Phe) and hydrophilic (due to Lys) character distributed along opposite amphiphilic faces, showed considerable antibacterial activity against clinically isolated bacteria together with Gram positive and Gram negative ATCC bacterial strains. However, the hemolytic capacity of the peptides was also significant. Decreasing the hydrophobic character of the molecule by replacing Trp or Phe with Leu residues while maintaining the basic contribution of Lys drastically reduced the hemolytic activity and only slightly decreased the bioactivity. Peptides composed of 9-10 amino acid residues with high hydrophobic and basic nature possess antibacterial activity but, in general, are less active than the larger counterpart peptides. By replacing all Trp residues of a short peptide by Leu residues, the activity was considerably reduced. Circular dichroism studies and antibacterial assays showed that shorter peptides with very low helical content, and thus deprived of amphiphilic character, still have appreciable bioactivity. This observation, coupled with the fact that due to their small size they cannot span the bacterial outer lipid bilayer, may suggest different mechanisms of action for long-chain vis-a-vis short-chain peptides.

5-o-desosaminylerythronolide a derivative

Abstract: A novel macrolide antibiotic having a potent antibacterial activity, 11-amino-3,11-dideoxy-3-oxo-5-O-desosaminyl-6-O-methylerythronolide A 11-N, 12-O-cyclic carbamate represented by formula (I), and a pharmaceutically acceptable acid addition salt thereof.

Antibacterial activity of polymeric sulfonium salts

Abstract: Polymeric sulfonium salts [CH 2 CH(PhR)] n (R= C 4 H 8 S + ) were shown to exhibit a high antibacterial activity against gram-negative bacteria.

Inhibition of antibacterial activity of essential oils by tween 80 and ethanol in liquid medium.

Abstract: The emulsifying agents used to disperse essential oils in culture media can interfere in the estimation of essential oils antimicrobial activity; we showed in this study that 0.2% Agar suspension was sufficient to obtain a stable dispersion of oregano and clove essential oils in liquid media comparable to the dispersions obtained with tween 80 (0.25%) or ethanol (0.2%). The dispersion with agar was as homogenous as a true solution in absolute ethanol. Furthermore, minimal inhibitory concentration and minimal lethal concentration for different bacterial species in presence of agar were significantly lower than those observed in presence of tween 80 or ethanol. This demonstrates the fact that solvents and detergents often used in antimicrobial studies significantly decreases the antibacterial activity of essential oils.

Polymeric phosphonium salts as a novel class of cationic biocides. IV: Synthesis and antibacterial activity of polymers with phosphonium salts in the main chain

Abstract: Polymers with phosphonium salts and different alkyl spacers in the main chain were prepared, and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. The antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds against each strain, and the effect of the molecular weight on the antibacterial activity was also observed for the compounds with the same spacer length. The antibacterial activity of the polymer samples bonded with different spacer lengths was found to increase with increasing the spacer length against both strains. © 1993 John Wiley & Sons, Inc.

Isolation of three antibacterial peptides from pig intestine: gastric inhibitory polypeptide (7-42), diazepam-binding inhibitor (32-86) and a novel factor, peptide 3910.

Abstract: Two antibacterial peptides, cecropin P1 and PR-39 (39-residue proline/arginine-rich peptide), from the upper part of pig small intestine have previously been isolated and characterized. We have now continued our search for antibacterial peptides in different side fractions generated during the isolation of intestinal hormones. Starting from one such fraction and monitoring activity against Bacillus megaterium, we isolated three homogeneous peptides by three consecutive chromatographic steps. Amino acid sequence analysis in combination with mass spectrometry identified two of the peptides as gastric inhibitory polypeptide(7–42) [GIP(7–42)] and diazepam-binding inhibitor(32–86) [DBI(32–86)], derived from factors already known. However, intact GIP and DBI have hardly any antibacterial activity by themselves. The third peptide constitutes a previously unknown structure, designated as peptide 3910 from its molecular mass. All three peptides showed good activity against B. megaterium. In addition. GIP(7–42) showed some activity against Streptococcus pyogenes and an Escherichia coli mutant with a defect in its outer membrane.

Antibacterial activity of long-chain alcohols against Streptococcus mutans

Abstract: The antibacterial activity against Streptococcus mutans of a number of naturally occurring compounds was tested. The emphasis was placed on a series of long-chain alcohols to gain new insight into their structural functions. Minimum activity seems to depend on the hydrophobic chain length from the hydrophilic hydroxyl group. Among the alcohols tested, 1-tridecanol was found to be the most effective for controlling this cariogenic bacterium

Polymeric phosphonium salts as a novel class of cationic biocides. V. Synthesis and antibacterial activity of polyesters releasing phosphonium biocides

Abstract: Polyesters were prepared which retained phosphonium biocides as counter ions of sodium sulfonate moieties incorporated into the polymers, and surface antibacterial activity of the polyester films against Staphylococcus aureus and Escherichia coli was explored. These films exhibited a high surface antibacterial activity against S. aureus and E. coli, particularly against S. aureus, and the activity was affected by the structure and the compositional ratio of the phosphonium salts. Amount of the released phosphonium salts was very small, so that liberation of the phosphonium biocides can be expected to occur over a long period. Morphological changes of the cells of S. aureus and E. coli in contact with the polyester films were evaluated by scanning electron microscopy. It was found that the surface antibacterial activity of the polyester films was rather bacteriostatic than bactericidal as evidenced by no morphological changes of the bacterial cells in contact with the phosphonium biocides © 1993 John Wiley & Sons, Inc.

TAN-1057 A-D, new antibiotics with potent antibacterial activity against methicillin-resistant Staphylococcus aureus. Taxonomy, fermentation and biological activity.

Abstract: Two Gram-negative bacteria were found to produce the new antibacterial antibiotics TAN-1057 A, B, C arid D. The producing bacteria were characterized and designated as Flexibacter sp. PK-74 and PK-176. These antibiotics were active against Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. TAN-1057 A inhibited protein biosynthesis in Escherichia coli and S. aureus. It showed excellent protective effects against an experimental methicillin-resistant S. aureus infection in mice.

Antibacterial activity against Streptococcus mutans of mate tea flavor components

Abstract: The 10 major volatile constituents were identified by GC-MS analysis as common flavor principles in mate tea obtained from various locations. Their antimicrobial activity against 13 microorganisms was tested. All of the volatiles tested exhibited moderate to weak activity with broad spectra. Some of them are bactericidal against one of the most important cariogenic bacteria, Streptococcus mutans. The antibacterial activity of the distillate against S. mutans was significantly enhanced by indole

Antibacterial fatty acid compositions

Abstract: This invention is directed to antibacterial activity of fatty acids and monoglycerides. More particularly, this invention is directed to the killing of bacteria by fatty acids and monoglycerides. The invention is also directed to antibacterial pharmaceutical compositions consisting essentially of inert pharmaceutical carrier and an antibacterial effective amount of one or more compounds selected from the group consisting of fatty acids and monoglycerides thereof, fatty alcohols, and ethers and lysophosphatidylcholine derivatives.

Antimicrobial activity of cashew apple flavor compounds

Abstract: The antimicrobial activity of the 10 most abundant flavor compounds of the cashew Ancardium occidentale (Anacardiaceae) apple has been tested. Most of them exhibited some activity against one or more of 14 microorganisms. Noticeably, (E)-2-hexenal showed activity against all of the microorganisms tested, including Gram-negative bacteria. In addition, the antibacterial activity of indole against Escherichia coli was enhanced 4-fold by combining it with a sublethal amount of (E)-2-hexenal. Furthermore, the minimum inhibitory concentration of this combination was found to be bactericidal by the time-kill curve method

Iron (III)-chelating resins. 3. Synthesis, iron (III)-chelating properties, and in vitro antibacterial activity of compounds containing 3-hydroxy-2-methyl-4(1H)-pyridinone ligands.

Abstract: The synthesis, iron (III)-chelating properties, and antibacterial activity of several compounds containing the 3-hydroxy-2-methyl-4(1H)-pyridinone (HMP) moiety are described. Using the HMP derivatives iron (III) could be mobilized from iron (III)-binding proteins at physiological pH with a rate order of transferrin > lactoferrin > ferritin. Addition of HMP-containing compounds to a growth medium at a concentration of 20 mM/L resulted in a complete inhibition of the growth of Escherichia coli and about 90% inhibition for Listeria inocua after 7 h of incubation at 37 degrees C. After inhibition of bacteria growth by the HMP derivatives growth started again when ferric ions were added to the medium, which implies that the antibacterial activity is due to a limitation of iron available to the organisms.

Antibacterial activity of NM394, the active form of prodrug NM441, a new quinolone.

Abstract: The in vitro antibacterial activity of NM394 was compared with those of other new quinolones. NM394 showed potent and broad-spectrum antibacterial activity against 2,606 recent clinical isolates. The activity of NM394 against gram-positive bacteria was 2- to 16-fold less than that of tosulfoxacin and sparfloxacin but was comparable to that of ofloxacin. Only against Streptococcus pyogenes was the activity of NM394 equal to that of sparfloxacin. Against gram-negative bacteria, NM394 showed antibacterial activity equal to that of ciprofloxacin. Against quinolone-resistant Pseudomonas aeruginosa (norfloxacin MIC, > 6.25 micrograms/ml), the activity of NM394 was greater than those of the other agents tested. NM394 was rapidly bactericidal at concentrations near the MIC. NM394 inhibited supercoiling activities of DNA gyrase purified from Staphylococcus aureus, Escherichia coli, and P. aeruginosa; the 50% inhibitory concentrations were 18.0, 0.41, and 2.05 micrograms/ml, respectively.

Preliminary Screening of Antibacterial and Antitumor Activities of Papua New Guinean Native Medicinal Plants

Abstract: Thirty-seven crude drug samples were prepared from different parts of 24 plants belonging to different families, and screened for antibacterial and antitumor activities. Antimicrobial activity was tested against gram positive (Staphylococcus albus and Bacillus sublilis) and gram negative (Pseudomonas aeruginosa and Klebsiella pneumonia) bacteria. Most of them exhibited antibacterial activity only against gram positive bacteria. Antitumor activities were screened in mice bearing sarcoma 180 cells. Five samples were found to mediate a significant increased in lifespan, indicating potential antitumor activity.

In vitro antibacterial activity of FK037, a novel pareteral broad-spectrum cephalosporin.

Abstract: FK037 is a new parenteral cephalosporin, which offers some advantages over the commercially available parenteral cephalosporins. It demonstrated potent broad-spectrum activity against clinical isolates of Gram-positive bacteria including methicillin-resistant staphylococci, and Gram-negative bacteria including Pseudomonas aeruginosa. Against clinical isolates of aerobic Gram-positive bacteria, FK037, like cefpirome, demonstrated more potent activity than ceftazidime, cefoperazone and ceftizoxime. It is noteworthy that FK037, on the basis of the MIC90s, was the most active of all the cephalosporins tested against methicillin-resistant Staphylococcus aureus (MRSA). It was similar in activity to cefpirome against methicillin-sensitive S. aureus (MSSA). Against clinical isolates of aerobic Gram-negative bacteria, FK037, like cefpirome, was superior to cefoperazone, similar to ceftazidime and inferior to ceftizoxime in activity. Against P. aeruginosa, FK037 was superior to cefoperazone, similar or slightly superior to cefpirome and inferior to ceftazidime in activity. However, FK037 exhibited significant activity against Citrobacter and Enterobacter which were highly resistant to ceftazidime, cefoperazone and ceftizoxime. FK037 had an advantage in that its bactericidal activity against S. aureus, Escherichia coli and P. aeruginosa at sub-MICs (1/2 or 1/4 the MIC) was much stronger than those of cefpirome and ceftazidime. Moreover, it exhibited potent bactericidal activity against MSSA, MRSA and P. aeruginosa in a pharmacokinetic in vitro model simulating human plasma concentrations after intravenous dosage of 0.125, 1.0 and 1.0 g, respectively. FK037 inhibited essential penicillin-binding proteins (PBPs), 1, 2 and 3 of S. aureus with a 50% inhibitory concentration (I50) of 0.58 micrograms/ml or lower. Of essential PBPs 3, 1a and 1b of E. coli and P. aeruginosa, FK037 inhibited PBP 3 at the lowest I50 (0.03 and 0.04 micrograms/ml, respectively) and PBPs 1a and 1b with I50 values of 2.7 micrograms/ml or lower. FK037, like cefpirome, was highly stable to hydrolysis by various beta-lactamases except Ic cephalosporinase from Bacteroides fragilis, and had extremely low affinity for beta-lactamases. Therefore, FK037 was more potent than ceftazidime in activity against beta-lactamase-producing bacteria except P. aeruginosa and Serratia marcescens. The ability of FK037 to penetrate the outer membrane of E. coli was slightly higher than that of ceftazidime, but slightly lower than that of cefpirome.

Quantitative Structure-Activity Relationships of Antibacterial Agents, 7-Heterocyclic Amine Substituted 1-Cyclopropyl-6,8-difluoro-4-oxoquinoline-3-carboxylic Acids.

Abstract: Quantitative structure-activity relationships (QSAR) of various 7-(3-substituted-azetidin-1-yl)-1-cyclopropyl-6,8-difluoro-1,4-dih ydro-4- oxoquinoline-3-carboxylic acids, 14-25, were studied to clarify the structural requirements for 3-substituted azetidines to potentiate antibacterial activity A good parabolic relationship seemed to exist between the relative mean antibacterial activity indices against five representative gram-negative bacteria, GNM, and the calculated hydrophobic parameters, CLOG P, of these molecules The CLOG P value of the most potent derivative was predicted to be around 23 On the other hand, against five representative gram-positive bacteria, the relative mean antibacterial activity indices, GPM, remained high and rather constant regardless of structural variation in the azetidine moiety In order to confirm these findings, the QSAR analysis was extended with success to the quinolonecarboxylic acids, 26-34, which bear various substituted pyrrolidine, piperazine and piperidine derivatives instead of azetidines The findings showed that the introduction of any amide substituent group to these heterocyclic amine moieties would lead to marked decrease in GNM, whereas incorporation of some amino substituent groups at a position two or three carbons remote from the N-1 position resulted in great enhancement of GNM As azetidine quinolones exhibited somewhat low in vivo antibacterial activities, possibly reflecting their lesser bioavailability, we finally selected 3-amino-4-methoxypyrrolidine as one of the most promising C-7 substituent groups based on our QSAR analysis

Isolation of Enterococcus faecium with Antibacterial Activity and Characterization of Its Bacteriocin

Abstract: Enterococcus faecium-100, screened from 120 strains of lactic acid bacteria, produced an antibacterial substance. From the narrow inhibitory spectrum, proteineous nature, and bactericidal mode of action, this antibacterial substance was concluded to be a bacteriocin and designated enterocin-100. E. faecium-100 produced bacteriocin during its log phase and in a narrow pH range of the culture broth around pH 6.3. Enterocin-100 was most active at neutral pH between 6 and 8, and was stable below pH 5.0. From the scanning electron microscopic observation, enterocin-100 caused morphorogical changes especially in highly sensitive bacteria at log and stationary phase.