Showing papers on "Antibacterial activity published in 1987"

A direct bioautographic tlc assay for compounds possessing antibacterial activity.

Abstract: A simple bioassay for the direct detection of antibacterial compounds on tlc plates has been developed. A series of natural products and different stationary phases were tested in order to establish the utility of the assay for the isolation of antibacterial compounds from higher plants.

Antibacterial agents specifically inhibiting lipopolysaccharide synthesis

Abstract: The spread of antibiotic resistance in Gram-negative bacteria has sustained a continuing search for new agents with antibacterial activity against this important class of bacterial pathogen. Because the biosynthesis of lipopolysaccharide (LPS) is unique to Gram-negative bacteria and required by them for growth and virulence, attempts have been made to discover or design antibacterial agents acting at this site; however, no such agents have so far been developed. We now present definitive experimental data documenting design of the first member of the class of antibacterial compounds which specifically inhibit LPS synthesis. The target enzyme is 3-deoxy-D-manno-octulosonate cytidylytransferase (CMP-KDO synthetase), a cytoplasmic enzyme which activates 3-deoxy-D-manno-octulosonate (KDO) for incorporation into LPS. A specific inhibitor of CMP-KDO synthetase, alpha-C-(1,5-anhydro-7-amino-2,7-dideoxy-D-manno-heptopyranosyl)-carboxy late was designed using results of our studies of the purified enzyme. LPS synthesis ceased and lipid A precursor accumulated, causing growth stasis and perturbation of outer membrane structure and function, following delivery of the inhibitor to the intracellular target by a peptide carrier. Antibacterial action required an intact oligopeptide permease system and specific intracellular aminopeptidase activity to release inhibitor from the peptide prodrug.

In vitro and in vivo activity of NY-198, a new difluorinated quinolone.

Abstract: NY-198 [1-ethyl-6,8-difluoro-1,4-dihydro-7-(3-methyl-1-piperazinyl)-4-oxo-3- quinolinecarboxylic acid hydrochloride] is a new difluorinated quinolone characterized by the presence of a C-methyl group at the 3 position of the piperazine moiety. It has a broad antibacterial spectrum. The in vitro antibacterial activity of NY-198 was almost the same as those of ofloxacin and norfloxacin, but far exceeded that of pipemidic acid. NY-198 was more active than norfloxacin against Pseudomonas maltophilia, Acinetobacter calcoaceticus, and anaerobic microorganisms. Cross resistance was not observed between NY-198 and various antibiotics including methicillin, gentamicin, and ampicillin. NY-198 had bactericidal activity at the MIC or slightly higher than the MIC. It showed excellent antibacterial activity against various systemic infections in mice. After oral administration, NY-198 was two times more active than or as active as ofloxacin and two to four times more active than norfloxacin.

Distribution and significance of heterotrophic marine bacteria with antibacterial activity

Abstract: Bacteria with antibacterial activity were isolated from seawater, sediments, phytoplankton, and zooplankton of Suruga, Sagami, and Tokyo Bays and from soft corals and sponges collected from the Taiwan coast. Of the 726 strains isolated, 37 showed antibacterial activity against either Vibrio parahaemolyticus (ATCC 17802) or Staphylococcus aureus (P209). Sediment harbored the lowest number of these forms of bacteria, and those from Tokyo Bay did not show any activity. Attached isolates showed greater activity compared with free-living forms. Relatively high numbers of strains with antibacterial activity were associated with phytoplankton. Among the zooplankton isolates, cladocerans harbored the maximum number of antibacterial strains. Isolates were more inhibitory to gram-positive test cultures. Autoinhibition was observed only among 8% of the isolates. Marine nonproducers were more susceptible. Pseudomonas/Alteromonas species made up 81.0% of isolates, of which 30% were pigmented strains. The absence or reduction in number of bacteria with antibacterial activity in Tokyo Bay is attributed to its eutrophic nature, which may tend to moderate the production of antibacterial compounds.

Antimicrobial activities of marine sponges from the Mediterranean Sea

Abstract: Extracts from marine sponges collected along the French coast of Mediterranean in 1983 have been tested for antibacterial and antifungal activities. The distribution of antimicrobial activities against five classes of microorganisms (5 Gram-positive and 5 Gram-negative terrestrial bacteria, 10 marine bacteria, 15 human pathogenic fungi and 5 phytopathogenic fungi) among 28 species of marine demosponges is reported. Antibacterial activity against Gram-positive bacteria (77%) is much more frequent than against Gram-negative bacteria (53%). Activity against marine bacteria and yeast is less frequent (32%). Those sponges which contain a large quantily of symbiotic bacteria display a weak antifungal activity.

Quinolonecarboxylic acids. 2. Synthesis and antibacterial evaluation of 7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzothiazine-6-carboxylic acids.

Abstract: A series of pyridobenzothiazine acid derivatives was synthesized and their in vitro antibacterial activity was evaluated. The 1,4-benzothiazine intermediates, which by Gould-Jacobs quinoline synthesis produced pyridobenzothiazine acids, were prepared by hydrolytic basic cleavage of substituted 2-aminobenzothiazoles and successive cyclocondensation with 1-bromo-2-chloroethane or alternatively with monochloroacetic acid, hence reduction by LiAlH4. The pyridobenzothiazine acids 10c, 30, and 31 show potent antibacterial activities against Gram-positive and Gram-negative pathogens. Structure-activity relationships are discussed. The compound 9-fluoro-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-d e] [1,4]benzothiazine-6-carboxylic acid (31) (MF-934) has been found to possess, together with the antibacterial activity, a weak acute toxicity and interesting pharmacokinetic characteristics in several animal species (rat, dog, monkey, man).

Non-antibacterial tetracycline compositions possessing anti-collagenolytic properties and methods of preparing and using same

Abstract: Tetracyclines having substantially no effective antibiotic or antibacterial activity and possessing anti-collagen-destructive enzyme activity or anti-collagenase activity and compositions containing the same have been found useful as anti-collagenolytic agents. Such tetracyclines and compositions containing the same are useful in the treatment of periodontal diseases, corneal ulcers, bone deficiency disorders, rheumatoid arthritis diseases characterized by excessive collagen destruction. A special aspect of this invention involves the incorporation of such tetracyclines in animal feed compositions for improved animal nutrition, such as may be evidenced by increased weight gain.

Antibacterial Activity of Flavonoids against Staphylococcus epidermidis, a Skin Bacterium

Abstract: An investigation was carried out on Okinawan plants to find antibacterial compounds against a human skin bacterium, Staphylococcus epidermidis, which causes acne vulgaris. A medicinal plant, Elaeagnus glabra, showed significant activity, and (—)-epigallocatechin (27) was isolated from the plant as an antibacterial constituent against the bacterium. Twenty-six flavonoids related to 27 were tested for the activity, galangin (7) being the most active species. Although a structure-activity study was attempted, no clear structural factor was deduced.

Xylocandin: a new complex of antifungal peptides. I. Taxonomy, isolation and biological activity.

Abstract: Xylocandin is a complex of novel peptides with potent antifungal activity that is produced by Pseudomonas cepacia ATCC 39277. The complex was isolated from the fermentation broth by extraction with butanol-methanol, 9:1, followed by collection of the precipitate formed upon concentration of the solvent extract. Purification was effected by chromatography on reversed phase and size exclusion gels followed by TLC on silica gel. These techniques afforded eight components: A1, A2, B1, B2, C1, C2, D1 and D2. A mixture of the two closely related components, xylocandins A1 and A2, displayed potent anticandidal and antidermatophytic activities in vitro. The activity was diminished by the presence of serum or vaginal washings. No antibacterial activity was demonstrable.

Antibacterial activity of the metabolites of ciprofloxacin and its significance in the bioassay.

Abstract: The antibacterial activity of the metabolites of ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3- quinolinecarboxylic acid, Bay o 9867; designated tradename: Ciprobay) M1, M2, M3 and M4 was tested with the agar dilution method against various Gram-positive and Gram-negative bacteria in comparison to ciprofloxacin, norfloxacin and nalidixic acid. The results show that M1 had only a weak antibacterial activity comparable to nalidixic acid, whereas M2 was significantly less active. M3, which is one of the main metabolites in urine has a broad antibacterial activity but was less active than ciprofloxacin or norfloxacin. M4 which is a very minor metabolite of ciprofloxacin was the most active compound with minimal inhibitory concentrations for strains of Escherichia coli or Klebsiella pneumoniae in the range of norfloxacin, whereas with staphylococci the antibacterial activity was comparable to ciprofloxacin. Possible interactions between ciprofloxacin and the metabolites in the bioassay system, using Escherichia coli (ICB 4004) were studied, to explain discrepancies between the microbiological assay and the HPLC-method reported in the literature. It could be demonstrated that under conditions where the concentration of ciprofloxacin exceeds or equals the concentration of the metabolites or mixtures of them no increase in the inhibition zones for ciprofloxacin could be observed, which would have led to false high values for ciprofloxacin in the bioassay system. From these data we conclude that the antibacterial activity of the metabolites in biological specimens, e.g. urine, does not influence the bioassay results.

Studies on new antibiotics SF2415. II. The structural elucidation.

Abstract: Structures of new antibiotics SF2415A1, A2, A3, Bl, B2 and B3 were deduced from spectroscopic analyses and degradation studies. The structure of SF2415A3, which has the most antibacterial activity, was proposed to be 3, 4a-dichloro-9-diazo-3, 4, 4a, 10a-tetrahydro-6-hydroxy-2, 2, 7-trimethyl-10a-[(E)-3, 7-dimethyl-2, 6-octadienyl]-(2H, 9H)naphtho[2, 3-b]pyran-5, 8, 10-trione. All of antibiotics SF2415 have a semi-naphthoquinone structure.

The effect of saturation with Zn2+ and other metal ions on the antibacterial activity of ovotransferrin.

Abstract: The antibacterial activity of metal complexes of ovotransferrin was tested "in vitro" against different bacterial species and the Zn2+ saturated ovotransferrin appeared to be the most active by comparison with the apo-protein and other metal complexes. Appropriate controls showed that such an effect was neither due to Zn2+ ions, nor to iron deprivation, but to a specific activity of the Zn-ovotransferrin complex. This antibacterial activity required a direct contact of Zn-ovotransferrin with the bacterial surface. In vivo experiments confirmed the higher antibacterial activity of Zn-ovotransferrin as compared with the apo-form.

Pyridonecarboxylic acids as antibacterial agents. 9. Synthesis and antibacterial activity of 1-substituted 6-fluoro-1,4-dihydro-4-oxo-7-(4-pyridyl)-1,8-naphthyridine-3- carboxylic acids.

Abstract: The title compounds (7a-e) with ethyl, 2-fluoroethyl, 2-hydroxyethyl, vinyl, or cyclopropyl groups, respectively, at C-1 were prepared by the method involving the Balz-Schiemann reaction of 2-(4-pyridyl)pyridine- and 7-(4-pyridyl)-1,8-naphthyridinediazonium tetrafluoroborates (15 and 27). The 1-ethyl, 1-(2-fluoroethyl), and 1-vinyl derivatives showed in vitro activities as potent as the corresponding 7-(1-piperazinyl) analogues against Staphylococcus aureus 209P JC-1 and Escherichia coli NIHJ JC-2 but were less active against Pseudomonas aeruginosa 12. Among the 7-(4-pyridyl) derivatives having the different C-1 substituent, 1-cyclopropyl derivative 7e was found to be the most active. In vivo efficacy of 7e was superior to that of enoxacin against experimental infections due to S. aureus 50774. Some aspects of structure-activity relationships associated with the C-1, C-6, and C-7 substituents were discussed.

Design and synthesis of peptide derivatives of a 3-deoxy-D-manno-2-octulosonic acid (KDO) analogue as novel antibacterial agents acting upon lipopolysaccharide biosynthesis.

Abstract: On the basis of the knowledge that the amino acid 3 (8-amino-2,6-anhydro-3,8-dideoxy-D-glycero-D-talo-octonic acid) is a potent inhibitor of 3-deoxy-manno-octulosonate cytidylyltransferase, attempts were made to design derivatives that would act as antibacterials against Gram-negative bacteria by inhibiting lipopolysaccharide biosynthesis Compound 3 and the derivatives 15 and 16 containing an additional amino acid were not lethal to bacteria However, compounds 17-22, which contain a N-terminally linked dipeptide, exhibited good antibacterial activity in vitro on testing against strains of the Gram-negative bacteria Escherichia coli and Salmonella typhimurium They have no activity against Gram-positive bacteria such as Staphylococcus aureus

Semisynthetic beta-lactam antibiotics. IV. Synthesis and antibacterial activity of new ureidocephalosporin and ureidocephamycin derivatives containing a catechol moiety or its acetate.

Abstract: New ureidocephalosporin and ureidocephamycin derivatives containing a catechol moiety or its acetate were prepared and their minimum inhibitory concentration values against various microorganisms were determined. Among these compounds, the ureidocephalosporins (2, 3Aa, 3Ba) and ureidocephamycins (4, 5) carrying a methyl group on the nitrogen atom of the ureido bond showed strong activities against Pseudomonas aeruginosa. 7β- [(R) -2-[3- (3, 4-Dihydroxybenzoyl) -3-methylureido] -2-phenylacetamido] -7α-methoxy-3- [(1-methyl-1H-tetrazol-5-yl) -thiomethyl] -3-cephem-4-carboxylic acid (5) had the most potent activity in vitro against gramnegative bacteria, its activity being 8-to 32-fold and 4-fold greater than those of cefoperazone and ceftazidime, respectively, against two strains of P. aeruginosa. The structure-activity relationship is discussed.

Design and synthesis of amphiphilic basic peptides with antibacterial activity and their interaction with model membrane.

Abstract: Twelve peptides having 4 to 6 basic amino acid residues in the hydrophobic amino acid sequence were designed and synthesized by the solution method to find peptides with potential activity against Gram-positive and -negative bacteria. CD study of the peptides demonstrated that they formed α-helical structures in the presence of phospholipid liposomes consequently to have amphiphilic property along the axis of helix. The peptides also induced the leakage of the dye carboxyfluorescein from phospholipid vesicles, indicating that the peptides possess the ability to perturb the membrane structure. These peptides showed antibacterial activity against Gram-positive bacteria, and some of them were also active against Gram-negative bacteria. Relationships between the structure and antibacterial activity of the synthetic peptides were discussed.

Studies on semi-synthetic 7 alpha-formamidocephalosporins. III. Synthesis and antibacterial activity of some 7 beta-[D-2-(aryl)-2-[(4-ethyl-2,3-dioxopiperazin-1-yl)carbonyl amino] acetamido]-7 alpha-formamidoceph-3-em-4-carboxylate derivatives.

Abstract: The synthesis and antibacterial activity of 7 beta-[D-2-(aryl)-2-[(4-ethyl-2,3-dioxopiperazin-1-yl) carbonylamino] acetamido]-7 alpha-formamidocephalosporins with various substituents at the C-3 position of the cephalosporin nucleus is described. Inhibition of Gram-positive and Gram-negative bacteria including beta-lactamase producing strains was observed with phenyl as the aryl residue. The 3,4-dihydroxyphenyl group further enhanced the activity against Gram-negative organisms; in this series, the 3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl] and 3-[(1-carboxymethyl-1H-tetrazol-5-yl)thiomethyl] analogues (2 and 12b) exhibited exceptional activity against Gram-negative bacteria, including Pseudomonas aeruginosa.

Synthesis and 3'-substituent effects of some 7 alpha-methoxy-1-oxacephems on antibacterial activity and alkaline hydrolysis rates.

Abstract: Relationships between intrinsic antibacterial activity and beta-lactam chemical reactivity of 7 beta-(phenylacetamido)-7 alpha-methoxy-1-oxacephems with various 3'-substituents were studied in order to clarify the effect of the 3'-substituent on the antibacterial activity The chemical reactivity of the beta-lactam ring estimated by pseudo-first-order rate constants log kobsdNMR of alkaline hydrolysis at pD 104 and 350 degrees C correlates well linearly with 13C NMR chemical shift differences (delta delta(4-3], infrared stretching frequencies of the beta-lactam carbonyl (vC = O), and sigma I values Values of log (1/CN), averaged for the MIC values for Escherichia coli, E coli NIH JC-2, E coli EC-14, and Klebsiella pneumoniae SRC-1, were taken as an estimation of the intrinsic antibacterial activity The log (1/CN) values of the compounds without good leaving groups correlated fairly well with log kobsdNMR values The comparatively high antibacterial activity of compounds with good leaving groups may be attributable to the different course of decomposition of these compounds

A new method for the direct incorporation of antibiotic in prosthetic vascular grafts.

Abstract: A procedure for the bonding of antibacterial agents directly to prosthetic vascular grafts has been developed. This method does not involve the use of carriers or surfactants which may cause local toxicity or thrombogenesis. Using this procedure, antibiotics can be bonded to the graft alone or in combination with a metal, such as silver. Incorporation of silver along with the antibiotic enhances the antibacterial activity and prolongs retention of the antibiotics in the prosthetic grafts. Silver mediated bonding appears to release the antibiotic biphasically. In the initial phase (40 to 50 per cent), the drug is rapidly released and, in the second phase, the rest is diffused gradually enabling the graft to retain antibacterial activity for a longer period of time.

Synthesis and in vitro activity of C-2 quaternary heterocyclic alkylthio carbapenems.

Abstract: The synthesis of new carbapenems having various (substituted) quaternary heterocyclic alkylthio groups at the C-2 position is described. The in vitro antibacterial activity and the dehydropeptidase-I susceptibility were examined. Some of these compounds (e.g., 11, 16, 26 and 27) showed an excellent wide spectrum of in vitro antibacterial activity including activity against Pseudomonas aeruginosa and greater stability than imipenem toward the dehydropeptidase-I.