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PubMed1994

Susceptibilities of 123 strains of Xanthomonas maltophilia to eight beta-lactams (including beta-lactam-beta-lactamase inhibitor combinations) and ciprofloxacin tested by five methods.

This study evaluated the susceptibility of 123 Xanthomonas maltophilia strains to ticarcillin, ticarcillin-clavulanate, ampicillin, amoxicillin-clavulanate, ampicillin-sulbactam, piperacillin, piperacillin-tazobactam, imipenem, and ciprofloxacin by Kirby-Bauer disk, E test, and Sensititre dehydrated microdilution MIC and conventional agar dilution MIC methodology. Intermediate susceptibility breakpoints for members of the family Enterobacteriaceae were used. When results were analyzed as MICs for 50 and 90% of the strains tested and percentages of strains susceptible at the breakpoint, good correlation between the methods was observed, with ticarcillin-clavulanate clearly the most active beta-lactam by all four methods. However, when the various methods were compared with the agar dilution methodology by regression analysis, poor r2 values (0.3 to 0.7) were obtained for compounds with sufficient on-scale values to permit analysis. When the number of strains with log2 ratios of reference agar dilution MICs to test MICs of +3 to -3 were analyzed, correlation was also poor, with many major and very major discrepancies for all methods tested. Results obtained with time-kill studies of nine strains with discrepant ticarcillin-clavulanate MICs appeared to correlate best when compared at 24 h with agar dilution MICs. The concentration of ticarcillin-clavulanate required to reduce the colony count by > or = 2 log10 reduction values for eight of nine strains compared with that for growth controls was < or = 16.0/2.0 micrograms/ml at 6 h and ranged from 16.0/2.0 micrograms/ml to 128.0/2.0 micrograms/ml at 24 h. The susceptibility method of choice for X. maltophilia has not yet been standardized, but time-kill studies correlated best with agar dilution MICs.

Anti-Bacterial Agents↗
PubMed1988

Analytical studies on beta-lactam antibiotics. II. Displacement effect of beta-lactam antibiotics on bilirubin bound to human serum albumin.

We established a method for determining the KD value as a measure of the bilirubin-displacing effect for drugs by using bilirubin oxidase, which is produced by Myrothecium verrucaria MT-1. This method makes it possible to conduct measurements of many beta-lactam antibiotics, including those which could not be determined by Brodersen's method. The KD values of latamoxef reported by many investigators based on Brodersen's method were higher than the true value owing to interaction of the drug with peroxidase and H2O2. Our KD value under the new enzyme conditions was 2.6 X 10(3). Little or no interaction of drug with the enzyme system was tentatively confirmed. Flomoxef, a newly developed drug, and 7432-S, under development in our company, had KD values of 0.4 X 10(3) and 2.8 X 10(3), respectively.

Anti-Bacterial Agents↗
PubMed1987

Influence of beta-lactam antibiotics on platelets. II. In vitro effects of some beta-lactam antibiotics on the biochemical responses of rat platelets.

The inhibitory mechanism of beta-lactam antibiotics on rat platelet activation was studied using carbenicillin (CBPC) as a representative of the antibiotics. CBPC suppressed all thrombin-induced cellular responses, including shape change, secretion and aggregation; however, it only suppressed aggregation of adenosine diphosphate (ADP)-induced responses. This suggested that ADP-binding to its own receptor was not affected by CBPC while thrombin-binding was inhibited. Inhibition of thrombin binding was confirmed using [125I]thrombin. In the case of ADP-stimulated platelets, fibrinogen-binding, which has an essential role for ADP-induced primary aggregation, was significantly suppressed by CBPC. Increase in a net negative charge of the membrane surface was observed after treatment of platelets with antibiotics and a good correlation was obtained between suppression of the platelet responses and increase in net negative charge of the antibiotics. These findings strongly suggest that the inhibition of ligand binding to their own receptors was due to the increase in the negative charge of the platelet membrane, which was probably caused by the antibiotic bound to the platelet membrane.

Adenosine Diphosphate↗
PubMed1986

Studies on monocyclic beta-lactam antibiotics. V. Synthesis and antibacterial activity of 3-[2-(2-aminothiazol-4-yl)-(Z)-2-(O-substituted oxyimino)-acetamido]-1-(1H-tetrazol-5-yl)-2-azetidinones having various functional groups at C-4 position of beta-lactam.

The synthesis and antibacterial activity of the 3-[2-(2-aminothiazol-4-yl)-(Z)-2-(O-substituted oxyimino)acetamido]-1-(1H-tetrazol-5-yl)-2-azetidinones++ + having various functional groups at C-4 position of beta-lactam are described. These compounds exhibited a strong activity against a variety of Gram-negative bacteria including beta-lactamase-producing strains. Among various C-4 substituents explored, the fluoromethyl and carbamoyloxymethyl moiety were found to increase the activity.

Anti-Bacterial Agents↗
PubMed1995

Comparison of different beta-lactam-glycopeptide-gentamicin combinations for an experimental endocarditis caused by a highly beta-lactam-resistant and highly glycopeptide-resistant isolate of Enterococcus faecium.

A synergistic bactericidal effect between penicillin, vancomycin, and gentamicin has been described against enterococci highly resistant to beta-lactams and glycopeptides. Since such a synergy was also observed in vitro between ceftriaxone, teicoplanin, and gentamicin against Enterococcus faecium 70/90, the efficacy of different combinations including penicillin or ceftriaxone, vancomycin or teicoplanin, and gentamicin was compared in vivo in experimental endocarditis. In vitro, all four triple combinations provided a bactericidal effect. In rabbits, after a 5-day treatment, the ceftriaxone-vancomycin-gentamicin combination was the most effective, both in reducing the total bacterial titers and in eradicating the subpopulation resistant to the synergy. Compared with the 5-day regimen, 10- and 20-day regimens of ceftriaxone-vancomycin-gentamicin, each followed by a 3-day antibiotic-free period, increased the number of sterilized animals but failed to avoid the emergence of resistant bacteria, which occurred in 10%-20% of animals.

Animals↗
PubMed1992

Enhancing effects of fluorescein on beta-lactam rash. II: Enhancing effects of fluorescein on generalized rash induced by beta-lactam antibiotics in guinea pigs.

Healthy volunteers, who were receiving intravenous injections of cefclidin (CFCL) with frequent concomitant use of fluorescein (F) and oxybuprocain (O) in the eyes for measurement of ocular tension, developed drug eruptions at the high frequency of 66.7%. The injection of CFCL alone induced the eruptions at an incidence of 2.8%. The cause of this high eruption rate was thought to be the simultaneous treatment with F and/or O. Therefore, we conducted experiments with CFCL-induced generalized rash (GR) in guinea pigs. Guinea pigs treated with F and O during both the phases of immunization and intraperitoneal elicitation developed CFCL rashes at a high frequency. This CFCL-rash was augmented by the treatment with F during either phase, but not by the treatment with O. Skin testing induced delayed type hypersensitivity (DTH) reaction to O in some animals, but the DTH to F was not induced in animals immunized with F in complete Freund's adjuvant. Furthermore, F augmented rashes induced not only by CFCL but also by other beta-lactam antibiotics such as cefsulodin and sulbenicillin. Accordingly, it is likely that F played a dominant role in the high incidence of drug eruptions during the volunteer trials with measurement of ocular tension.

Animals↗
PubMed1982

Antigenicity of beta-lactam antibiotic preparations: production of IgE antibodies to beta-lactam antibiotic and their cross-reaction within the antibiotic group.

BALB/C mice were immunized with conjugate of benzylpenicillin or ampicillin with Ascaris suum extract. The mice developed IgE antibodies to penicillin, which were found to react with commercially available penicillin preparations in the PCA system. Elimination of polymerized penicillin by Sephadex chromatography from tested preparations could not diminish their activities to elicit PCA. High pressure liquid chromatographic (HPLC) separation of PcG preparation yielded fractions unable to elicit PCA. On the other hand, all fractions from ABPC retained the activity even after the HPLC purification. A comparative estimation of cross-reactivity of IgE and IgE antipenicillin antibodies showed that IgE antibodies cross-reacted with a variety of beta-lactam antibiotics in a high degree.

Ampicillin↗
PubMed1982

Intestinal absorption of several beta-lactam antibiotics. III. Competitive inhibition behavior among zwitterionic beta-lactam antibiotics in the rat intestinal absorption.

Competitive inhibitory behavior among zwitterionic beta-lactam antibiotics in the rat intestinal absorption process was examined. Intestinal absorption of cephradine and cephalexin was significantly inhibited by cyclacillin. The mutual inhibition between these amino-cephalosporins was also observed. On the other hand, in the pretreatment experiments with cyclacillin, it was found that absorption of cephradine was significantly inhibited, but the inhibitory effect of cyclacillin was not observed for cephalexin. These results showed that cephradine had a common carrier-mediated transport mechanism with cyclacillin which is not present in the absorption process of cephalexin. It was postulated that the mutual inhibition between cephradine and cephalexin is based on the competitive inhibition in the accumulation or uptake by the intestinal mucosa.

Animals↗
PubMed1986

Influence of beta-lactam antibiotics on platelets. I. In vivo effects of latamoxef and related beta-lactam antibiotics on membrane proteins and glycoproteins of rat platelets.

The effects of latamoxef (moxalactam) and the other beta-lactam antibiotics on platelet membrane were studied by intravenous administration of these drugs to rats for 8 d. Blood was taken from the abdominal aorta and washed platelets were prepared by centrifugation. Platelet membrane proteins labeled with 125I and the glycoproteins with 3H were used and analyzed by electrophoresis. Differences of membrane proteins and glycoproteins, compared with the control, were not observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two dimensional electrophoresis.

Animals↗
PubMed1988

[Randomized trial of empirical antibiotic therapy in febrile episodes after bone marrow transplantation. Comparison of an aminoglycoside-beta lactam (tobramycin-ticarcillin) combination with 2 beta-lactam antibiotics (ticarcillin-latamoxef)].

From February 1986 to July 1987, 87 patients who underwent an autologous or allogeneic bone marrow transplantation were randomized to receive ticarpen tobramycin or ticarpen moxalactam for their first febrile episode. Forty received ticarpen tobramycin and 47 ticarpen moxalactam. The two groups were similar according to age, sex, conditioning regimen, underlaying pathology and duration of granulocytopenia. We observed 58.6% of fever unknown origin and 37% of bacteremia. A similar number of clinical and bacteriological successes occurred in the two groups. Hepatic and renal toxicities were similar in the two groups. Vancomycin was widely used in these patients without particular justification. We conclude that the use of two beta lactam is a possible antibiotherapy in marrow transplantation where renal function should be preserved from additional toxicity.

Adolescent↗
PubMed2003

Intramolecular cyclization with nitrenium ions generated by treatment of N-acylaminophthalimides with hypervalent iodine compounds: formation of lactams and spiro-fused lactams.

N-Phthalimido-N-acylnitrenium ions are generated from N-acylaminophthalimides, a new class of precursors, by treatment with hypervalent iodine compounds (PIFA and HTIB). In HFIP, the nitrenium ions undergo intramolecular electrophilic substitution reactions to afford N-aminonitrogen heterocycles in high yields. In TFEA, spirodienones bearing the 1-azaspiro[4.5]decane skeleton are obtained by treatment of N-phthalimido-3-(4-halogenophenyl)propanamides with HTIB as a result of ipso attack of the intermediate nitrenium ion. Similarly, using PIFA in TFEA, ipso cyclization of unactivated benzenoid compounds occurs to afford spirodiene derivatives. This involves loss of aromaticity despite the absence of other activating substituents on the phenyl group.

Indicators and Reagents↗
PubMed2005

Nitrenium ion azaspirocyclization-spirodienone cleavage: a new synthetic strategy for the stereocontrolled preparation of highly substituted lactams and N-hydroxy lactams.

[reaction: see text] Although 1,4-cyclohexadienes 2, obtained through the Birch reduction of arenes 1, have found widespread use as masked beta-oxo carbonyl synthons 3, the possibility that 2,5-cyclohexadienones 5 might also be employed to the same end has been overlooked despite their ready availability. As part of our ongoing investigation of the synthetic chemistry of nitrenium ions, we have developed a novel and efficient strategy for the stereoselective preparation of di- and trisubstituted azetidinone, pyrrolidinone, and piperidinone derivatives, which features the ozonolytic cleavage of azaspirocyclic 2,5-cyclohexadienones 12. For example, ozonolysis of spirodienone 12c in CH2Cl2 and reductive workup with dimethyl sulfide generated unstable beta-formyl ester 21, whereas cleavage in MeOH followed by reduction with thiourea led to hemiacetal 22. While both 21 and 22 partially decompose upon exposure to silica gel, they can be trapped in situ, with a variety of weakly basic nucleophiles, to usefully substituted products. The requisite spirodienone substrates are readily accessible through the nitrenium ion cyclization of alkyl omega-arylhydroxamates 10, which proceeds with moderate to high diastereoselectivity.

Amides↗