RESUMO
BACKGROUND: Acyclovir (ACV) resistant herpes simplex virus (HSV) isolates can be readily selected in animal infection models receiving suboptimal ACV treatment, however no comparative studies of the emergence of resistance following suboptimal treatment with valacyclovir (VCV) or famciclovir (FCV), the prodrugs of acyclovir and penciclovir, respectively, have been reported. METHODS: Mice (n = 30) were infected with HSV type 1 or 2 in the ear pinnae and administered oral prodrugs at one fifth a dose previously shown to be effective. To select and amplify drug-resistant HSV, a total of seven consecutive in vivo passages with suboptimal treatment were performed for each virus sample and progeny virus from each passage was characterized by the plaque reduction (PRA) and plating efficiency assays (PEA). RESULTS: No drug-resistant HSV-2 and only a single drug-resistant HSV-1 variant were identified. Virus recovered from the first three sequential passages of this HSV-1 sample was susceptible by PRA, although the proportion of resistant virus recovered gradually increased upon passage. The resistant HSV-1 phenotype was confirmed by PRA after four sequential passages in mice. Unexpectedly, this in vivo-selected drug-resistant HSV-1 failed to yield an infection completely refractory to treatment in subsequent passages. CONCLUSIONS: Sub-optimal therapy of immunocompetent mice with either VCV or FCV did not readily select for HSV-mutants resistant to either ACV or PCV, suggesting that selection of resistance with either prodrug remains difficult using this system. Futhermore, this study suggests that the PEA may represent a useful adjunct to the PRA for monitoring alterations in the proportion of drug-resistant virus even when no change in IC50 is apparent.
Assuntos
Aciclovir/análogos & derivados , Aciclovir/uso terapêutico , Antivirais/uso terapêutico , Herpes Simples/tratamento farmacológico , Pró-Fármacos/uso terapêutico , Simplexvirus/efeitos dos fármacos , Aciclovir/farmacologia , Administração Oral , Animais , Antivirais/farmacologia , Modelos Animais de Doenças , Farmacorresistência Viral , Feminino , Guanina , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Pró-Fármacos/metabolismo , Pró-Fármacos/farmacologia , Simplexvirus/fisiologia , Carga ViralRESUMO
As part of a search for novel inhibitors of HIV-1 reverse transcriptase, the acetone extract of the giant African snail, Achatina fulica, was shown to be active. Fractionation of the extract yielded inophyllums A, B, C, and E and calophyllolide (1a, 2a, 3a, 3b, and 6), previously isolated from Calophyllum inophyllum Linn., a known source of nutrition for A. fulica. From a methanol/methylene chloride extract of C. inophyllum, the same natural products in considerably greater yield were isolated in addition to a novel enantiomer of soulattrolide (4), inophyllum P (2b), and two other novel compounds, inophyllums G-1 (7) and G-2 (8). The absolute stereochemistry of inophyllum A (1a) was determined to be 10(R), 11(S), 12(S) from a single-crystal X-ray analysis of its 4-bromobenzoate derivative, and the relative stereochemistries of the other inophyllums isolated from C. inophyllum were established by a comparison of their 1H NMR NOE values and coupling constants to those of inophyllum A (1a). Inophyllums B and P (2a and 2b) inhibited HIV reverse transcriptase with IC50 values of 38 and 130 nM, respectively, and both were active against HIV-1 in cell culture (IC50 of 1.4 and 1.6 microM). Closely related inophyllums A, C, D, and E, including calophyllic acids, were significantly less active or totally inactive, indicating certain structural requirements in the chromanol ring. Altogether, 11 compounds of the inophyllum class were isolated from C. inophyllum and are described together with the SAR of these novel anti-HIV compounds.
Assuntos
Cromanos/isolamento & purificação , HIV-1 , Inibidores da Transcriptase Reversa , Árvores , Acetilação , Animais , Cromanos/química , Cromanos/farmacologia , Cristalização , Cristalografia por Raios X , Transcriptase Reversa do HIV , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Espectroscopia de Ressonância Magnética , Conformação Molecular , Estrutura Molecular , Caramujos/química , Relação Estrutura-AtividadeRESUMO
Synthetic peptide mimetic inhibitors of HIV-1 protease effectively block spread of infectious virus in acutely infected T-cells. These compounds also inhibit production of infectious virions from chronically infected T-cell lines. In order to determine the potential for drug interaction effects on antiviral activity, an HIV-1 protease inhibitor (SK&F 108922) and AZT were studied in three different in vitro models of HIV-1 infection of T-cell lines, specifically, (1) acutely infected cells infected at low multiplicity, (2) HIV-1 chronically-infected cells and (3) co-cultivations of chronically infected with non-infected cells. Upon co-treatment, these compounds demonstrated synergy in Molt4 or H9 cells acutely infected with HIV-1 strain IIIB. Either compound alone was a potent inhibitor of HIV-1 in co-cultivations of uninfected and chronically infected cells. In combination treatments of co-cultures, SK&F 108922 demonstrated strong synergy with AZT. Treatment of H9/IIIB chronically infected cells demonstrated no inhibitory effect by AZT treatment (EC50 = > 100 microM) whereas SK&F 108922 was inhibitory (EC50 = 3 microM). Upon co-treatment of H9/IIIB chronically infected cultures with both compounds, the antiviral activity was similar to that of the protease inhibitor alone suggesting no drug interaction. In the co-cultivation experiments, AZT's antiviral effect was most likely due to blocking spread of acute infection to uninfected cells in the culture. No antagonistic effects were observed with AZT and SK&F 108922 co-treatments. These results clearly demonstrate that an HIV-1 protease inhibitor can exert a potent antiviral effect on chronically infected T-cells in contrast to AZT and is capable of potent synergy with AZT in acute and co-culture in vitro infection models.
Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Inibidores da Protease de HIV/farmacologia , Oligopeptídeos/farmacologia , Zidovudina/farmacologia , Sequência de Aminoácidos , Linhagem Celular , Doença Crônica , Sinergismo Farmacológico , Transcriptase Reversa do HIV , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , Humanos , Modelos Biológicos , Dados de Sequência Molecular , DNA Polimerase Dirigida por RNA/biossíntese , DNA Polimerase Dirigida por RNA/metabolismo , Replicação Viral/efeitos dos fármacosRESUMO
Analogues of peptides ranging in size from three to six amino acids and containing the hydroxyethylene dipeptide isosteres Phe psi Gly, Phe psi Ala, Phe psi NorVal, Phe psi Leu, and Phe psi Phe, where psi denotes replacement of CONH by (S)-CH(OH)CH2, were synthesized and studied as HIV-1 protease inhibitors. Inhibition constants (Ki) with purified HIV-1 protease depend strongly on the isostere in the order Phe psi Gly greater than Phe psi Ala greater than Phe psi NorVal greater than Phe psi Leu greater than Phe psi Phe and decrease with increasing length of the peptide analogue, converging to a value of 0.4 nM. Ki values are progressively less dependent on inhibitor length as the size of the P1' side chain within the isostere increases. The structures of HIV-1 protease complexed with the inhibitors Ala-Ala-X-Val-Val-OMe, where X is Phe psi Gly, Phe psi Ala, Phe psi NorVal, and Phe psi Phe, have been determined by X-ray crystallography (resolution 2.3-3.2 A). The crystals exhibit symmetry consistent with space group P6(1) with strong noncrystallographic 2-fold symmetry, and the inhibitors all exhibit 2-fold disorder. The inhibitors bind in similar conformations, forming conserved hydrogen bonds with the enzyme. The Phe psi Gly inhibitor adopts an altered conformation that places its P3' valine side chain partially in the hydrophobic S1' pocket, thus suggesting an explanation for the greater dependence of the Ki value on inhibitor length in the Phe psi Gly series. From the kinetic and crystallographic data, a minimal inhibitor model for tight-binding inhibition is derived in which the enzyme subsites S2-S2' are optimally occupied. The Ki values for several compounds are compared with their potencies as inhibitors of proteolytic processing in T-cell cultures chronically infected with HIV-1 (MIC values) and as inhibitors of acute infectivity (IC50 values). There is a rank-order correspondence, but a 20-1000-fold difference, between the values of Ki and those of MIC or IC50. IC50 values can approach those of Ki but are highly dependent on the conditions of the acute infectivity assay and are influenced by physiochemical properties of the inhibitors such as solubility.
Assuntos
Antivirais/síntese química , Inibidores da Protease de HIV , HIV-1/fisiologia , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Inibidores de Proteases/síntese química , Replicação Viral/efeitos dos fármacos , Sequência de Aminoácidos , Western Blotting , Linhagem Celular , Etilenos/química , Etilenos/farmacologia , Protease de HIV/química , Protease de HIV/isolamento & purificação , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , Humanos , Indicadores e Reagentes , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Oligopeptídeos/síntese química , Ligação Proteica , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Relação Estrutura-Atividade , Especificidade por Substrato , Linfócitos T , Difração de Raios XRESUMO
The p170 and p180 forms of topoisomerase II have been compared. The concentration dependence of ATP for catalytic activity of the two forms of the enzyme was identical, and each was equally sensitive to novobiocin. Orthovanadate was found to be a potent inhibitor of catalytic activity of both p170 and p180, with an IC50 value of about 2 microM for each. Under standard reaction conditions, relaxation of supercoiled pBR322 by p180 was highly processive, while p170 performed the same reaction in a distributive manner. The optimal concentration of KCl for catalytic activity of p180 was 20-30 mM higher than that for p170. Comparison of their thermal stability showed that p180 was inactivated at twice the rate of p170. Teniposide and merbarone selectively inhibited catalytic activity of p170, requiring concentrations 3-fold and 8-fold lower, respectively, than those required for equivalent inhibition of p180. Similar selectivity for p170 was seen for teniposide-stimulated DNA cleavage or its inhibition by merbarone. Analysis of sites of DNA cleavage indicated a subset of sites that were either preferred or unique for each of the enzymes. A synthetic oligonucleotide representative of p170 sites selectively inhibited the p170 enzyme. Immunoblotting of p170 and p180 from U937 cells at different stages of proliferation showed that p170 levels declined as the cells reached the plateau phase of growth, while p180 levels were low during rapid proliferation and increased as the growth rate slowed. The data indicate that the p170 and p180 forms of topoisomerase II can be distinguished biochemically, pharmacologically, and by differential cellular regulation.
Assuntos
DNA Topoisomerases Tipo II/metabolismo , DNA/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Antineoplásicos/farmacologia , Catálise , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Immunoblotting , Peso Molecular , Conformação de Ácido Nucleico , Plasmídeos , Inibidores da Topoisomerase IIRESUMO
Topoisomerase II was purified from an amsacrine-resistant mutant of P388 leukemia. A procedure has been developed which allows the rapid purification of nearly homogeneous enzyme in quantities sufficient for enzyme studies or production of specific antisera. The purified topoisomerase II migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as two bands with apparent molecular masses of 180 (p180) and 170 kDa (p170); both proteins unknotted P4 DNA in an ATP-dependent manner and displayed amsacrine-stimulated covalent attachment to DNA. Staphylococcus V8 protease cleavage patterns of p170 and p180 showed distinct differences. Specific polyclonal antibodies to either p170 or p180 recognized very selectively the form of the enzyme used to generate the antibodies. Immunoblotting with these specific antibodies showed that both p180 and p170 were present in cells lysed immediately in boiling sodium dodecyl sulfate. Comparison of the purified topoisomerase II from amsacrine-resistant P388 with that from amsacrine-sensitive P388 demonstrated that each cell type contained both p180 and p170; however, the relative amounts of the two proteins were consistently different in the two cell types. The data strongly suggest that p170 is not a proteolytic fragment of p180. Thus, P388 cells appear to contain two distinct forms of topoisomerase II.
Assuntos
Amsacrina/uso terapêutico , DNA Topoisomerases Tipo II/isolamento & purificação , Isoenzimas/isolamento & purificação , Leucemia P388/tratamento farmacológico , Leucemia Experimental/tratamento farmacológico , Animais , DNA/metabolismo , Resistência a Medicamentos , Técnicas de Imunoadsorção , Conformação de Ácido NucleicoRESUMO
Results of filter elution assays of lesions produced in the DNA of cultured L1210 cells by the antineoplastic alkaloid camptothecin support the notion that topoisomerase I is an intracellular target of this drug. One to 10 microM camptothecin induced DNA single-strand, but not double-strand, breaks when incubated with intact cells or with their isolated nuclei. Approximately one half of the strand breakage was protein concealed, as judged by filter elution. Camptothecin-induced, protein-concealed DNA strand breaks disappeared rapidly after drug removal. DNA-protein cross-links were generated by camptothecin with frequencies approximately equal to those of protein-concealed DNA strand breaks. It is likely that camptothecin can inhibit topoisomerase I in intact cells in a manner similar to that in which other antineoplastic agents such as amsacrine or teniposide inhibit topoisomerase II. DNA-breaking lesions other than those resulting from trapped topoisomerase I-DNA complexes may also be generated by camptothecin. The yields of DNA strand breaks induced by camptothecin, amsacrine, or teniposide were approximately doubled when cells were incubated for 16 h with 3-aminobenzamide, an inhibitor of poly(ADP ribosylation) of proteins, prior to 1-h exposure to the antineoplastic compounds. 3-Aminobenzamide also enhanced the cytotoxic action of camptothecin, amsacrine, and teniposide. These results suggest that protein-concealed strand breaks can be lethal lesions and that intracellular topoisomerase I and II activity may be regulated coordinately through poly(ADP ribosylation).
Assuntos
Camptotecina/toxicidade , Leucemia L1210/patologia , Inibidores da Topoisomerase I , Animais , Dano ao DNA , DNA de Neoplasias/isolamento & purificação , DNA de Neoplasias/efeitos da radiação , Leucemia L1210/enzimologia , Camundongos , Proteínas de Neoplasias/efeitos da radiaçãoRESUMO
The ability of gold coordination complexes to bind to DNA and produce inter-strand cross-links in DNA was assessed in an assay system based on the fluorescence properties of the DNA intercalative dye, ethidium bromide. Results from these studies using a variety of gold(I) and gold(III) complexes suggest that the ability of gold complexes to bind to and produce inter-strand cross-links in DNA is not dependent on the oxidation state of gold in the complex but is influenced by the nature of the coordinating ligands. Those complexes in which the gold was ligated through one or more weakly coordinating ligands showed evidence for DNA binding. However, only those complexes with two or more of these relatively weak coordinating ligands produced inter-strand cross-links. Both the amount of binding to and cross-linking of DNA by these compounds were decreased by treatment of the gold-DNA complex with 2-mercaptoethanol and other thiol containing agents. As shown by agarose gel electrophoresis, 2-mercaptoethanol caused a dissociation of the gold-DNA complexes and a regeneration of closed circular superhelical pBR322 DNA. DNA strand breakage also resulted from treatment of a number of gold-DNA complexes with 2-mercaptoethanol; this was observed with the gold compounds which were shown to produce inter-strand cross-links in DNA. The amount of DNA strand breakage produced by treatment of gold-DNA complexes with 2-mercaptoethanol was influenced by the initial conformation of the DNA; gold-DNA complexes which resulted from the binding of gold compounds to covalently closed superhelical DNA were more sensitive to the breakage induced by 2-mercaptoethanol treatment than those complexes in which closed circular, relaxed DNA was used as substrate. The DNA breakage was not reduced in partially anaerobic conditions or by free-radical scavengers, suggesting that it is not mediated by oxygen. The results are discussed with respect to the potential for the interaction of gold complexes with intracellular DNA and chromatin and their biological implications.
Assuntos
DNA/metabolismo , Ouro/farmacologia , Anaerobiose , Animais , Bovinos , Cisplatino/farmacologia , Reagentes de Ligações Cruzadas/farmacologia , DNA Super-Helicoidal/metabolismo , Eletroforese em Gel de Ágar , Etídio , Fluorescência , Radicais Livres , Ouro/metabolismo , Mercaptoetanol/farmacologia , Conformação de Ácido Nucleico , Oxigênio/metabolismo , PlasmídeosRESUMO
A method is described by which the growth inhibitory effects of cytotoxic compounds and fermentation broth cultures on adherent tumor cell lines can be quantitated. Cells are seeded into 96-well microtiter plates and 16 hours later the test compounds or broths are added to the wells. Cell growth is measured after three days (B16 mouse melanoma cells) or six days (HT-29, human colon carcinoma cells) by first fixing adherent cells, staining with Giemsa stain, washing away excess stain, then solubilizing stained cells with HCl. Absorbance is determined using a microELISA spectrophotometer and the data are transferred to and analyzed by a computer. The assay is rapid and reproducible and can be used to identify fermentation broths with cytotoxic components. Addition of DNA into the assay mixture (cells plus compound) inhibits the cytotoxic activities of certain DNA-reactive agents. The results of this study demonstrate the application of this assay system for primary and secondary evaluation of fermentation broths for in vitro antitumor activity.
Assuntos
Antibióticos Antineoplásicos/análise , Antineoplásicos Fitogênicos/análise , Avaliação Pré-Clínica de Medicamentos/métodos , Animais , Bioensaio , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Neoplasias do Colo/patologia , DNA/metabolismo , Relação Dose-Resposta a Droga , Fermentação , Humanos , Melanoma/patologia , CamundongosRESUMO
A reverse hemagglutination assay was used to study adherence to human erythrocytes by Escherichia coli H10407, which possesses colonization factor antigen I. Pretreatment of erythrocytes with trypsin, chymotrypsin, papain, protease, and neuraminidase completely abolished attachment reactivity. In addition, the hemagglutination reaction was prevented by the presence of urea and guanidine. In contrast, the lipases, nucleotide hydrolases, exoglycosidases, and reagents affecting disulfide or sulfhydryl moieties did not alter receptor reactivity. Glycoconjugates containing sialic acid inhibited the hemagglutination reaction. Furthermore, a sialoglycoprotein isolated from the erythrocyte membrane inhibited the hemagglutination reaction. Collectively, these data indicate that the erythrocyte receptor responsible for attachment by E. coli possessing colonization factor antigen I is a sialoglycoconjugate.
Assuntos
Antígenos de Bactérias/imunologia , Membrana Eritrocítica/metabolismo , Escherichia coli/patogenicidade , Proteínas de Fímbrias , Fímbrias Bacterianas/metabolismo , Sialoglicoproteínas/sangue , Adesividade , Sítios de Ligação , Membrana Eritrocítica/microbiologia , Escherichia coli/imunologia , Fímbrias Bacterianas/imunologia , HumanosRESUMO
Clinical experience suggests that drugs that interact with and damage DNA are useful in cancer chemotherapy (H. Umezawa , p. 43-72, in V. T. DeVita , Jr., and H. Busch [ed.], Methods in Cancer Research; Cancer Drug Development, vol. XVI, 1979). Prescreening systems for antitumor agents in natural products require assays that are exquisitely sensitive, since the active components are often produced in quantities of micrograms per milliliter or less. One assay used to identify agents that interact with DNA is the biochemical induction assay, utilizing Escherichia coli BR 513 (R. K. Elespuru and R. J. White, Cancer Res. 43:2819-2830, 1983). In this paper we describe a genetic modification of strain BR 513 that displays an expanded spectrum of activity. This strain may provide an improved prescreen for detecting natural products that interact with DNA.
Assuntos
Antibióticos Antineoplásicos/farmacologia , Escherichia coli/genética , Plasmídeos , Ampicilina/farmacologia , Bleomicina/farmacologia , DNA Bacteriano/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Testes de Sensibilidade Microbiana , Ácido Nalidíxico/farmacologia , Plasmídeos/efeitos dos fármacos , Transformação BacterianaRESUMO
A culture of Escherichia coli possessing colonization factor antigen I was subjected to isopycnic separation on Percoll gradients. The results demonstrated successful division of the culture into two populations: (i) bacteria which cause mannose-resistant hemagglutination and (ii) bacteria which lack the ability to hemagglutinate in the presence of mannose.
Assuntos
Antígenos de Bactérias/análise , Escherichia coli/isolamento & purificação , Proteínas de Fímbrias , Centrifugação Isopícnica , Escherichia coli/imunologia , Povidona , Dióxido de SilícioRESUMO
Two strains of Escherichia coli, producing different colonization factor antigens (CFA), were monitored for the population density of CFA-producing bacteria after repeated subculture. The production of CFA was estimated by flooding agar plates containing isolated colonies with suspensions of human or bovine erythrocytes. The erythrocytes were suspended in a low-ionic-strength buffer and were fixed to CFA-positive colonies with a 1.0% tannic acid solution. Strain H-10407, possessing CFA/I fimbriae, showed a rapid loss of the hemagglutinin when subcultured, whereas strain CL-9699, producing CFA/II, was very stable. By using the hemadsorption assay, we could rapidly and easily distinguish CFA- positive colonies from the CFA-negative variants. A survey of additional E. coli strains demonstrated the utility and specificity of the hemadsorption technique used.
Assuntos
Antígenos de Bactérias/análise , Escherichia coli/imunologia , Proteínas de Fímbrias , Animais , Bovinos/sangue , Escherichia coli/classificação , Hemadsorção , Hemaglutinação , HumanosRESUMO
The hemagglutination (HA) activity of two strains of Escherichia coli, each possessing different colonization factor antigens (CFA), was examined under different test conditions. The effects of ionic strength, temperature, pH, cations, and reaction surface on erythrocyte (RBC) agglutination were analyzed. Strain H-10407 (CFA/I) caused the agglutination of human, bovine, and chicken RBC, whereas strain CL-9699 (CFA/II) agglutinated only bovine and chicken RBC. The HA activity of both strains increased with decreasing ionic strength, pH, and temperature, the effects of temperature being negligible at low ionic strength. When accounting for ionic strength, the presence of Ca2+, Mg2+, Fe2+, or Fe3+ ions did not increase the HA activity of these bacteria. Optimum conditions for HA of reactive RBC by bacteria included low ionic strength (less than 50 mM) and slightly acidic pH (6.0 to 7.0). Use of a low-ionic-strength medium permitted application of microtitration methods to visualize the HA reactions. Storage of RBC in low-ionic-strength medium did not change their HA properties, and the use of this medium proved superior to saline in overcoming HA variation observed with different preparations of RBC.
Assuntos
Escherichia coli/imunologia , Hemaglutinação , Animais , Antígenos de Bactérias , Cátions Bivalentes/farmacologia , Bovinos , Galinhas , Compostos Férricos/farmacologia , Compostos Ferrosos/farmacologia , Cobaias , Testes de Hemaglutinação , Humanos , Concentração de Íons de Hidrogênio , Concentração Osmolar , TemperaturaRESUMO
Three cephalosporins with 7-(2-hydroxyiminophenylacetamido) side chains (SK&F 79433, 80000 and 80303), differing in their 3-substituents, exhibited similar broad-spectrum antibacterial activity in vitro against strains of Staphylococcus aureus, Streptococcus faecalis and various Gram-negative bacilli. All three were active in vivo (s.c., mouse) against S. aureus, Escherichia coli or Klebsiella pneumoniae, but they differed significantly in serum pharmacokinetic profiles. SK&F 80303 produced high and extremely prolonged serum levels and protected mice when administered up to 24 hours prior to challenge with beta-lactamase-producing S. aureus or K. pneumoniae. It was resistant to hydrolysis by beta-lactamases from S. aureus, and variably so to beta-lactamases from E. coli strains. SK&F 80303 was bacteriolytic to logarithmically growing S. aureus, E. coli, Proteus mirabilis, K. pneumoniae and Enterobacter cloacae (partially). SK&F 80303 illustrates further the effect of the 3-sulfoalkyltetrazole substituent on the pharmacokinetic properties of cephalosporins. Its combined biological properties make it a possible candidate for therapeutic and long-term prophylactic use.
Assuntos
Bactérias/efeitos dos fármacos , Cefalosporinas/farmacologia , Animais , Bactérias/enzimologia , Proteínas Sanguíneas/metabolismo , Cefazolina/farmacologia , Cefalosporinase/metabolismo , Cefalosporinas/metabolismo , Haplorrinos , Cinética , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Ligação Proteica , Coelhos , Fatores de TempoRESUMO
Cefazaflur has a broad-spectrum of in vitro antibacterial activity equal to or greater than that of the commercially-available cephalosporins. In addition, cefazaflur has activity against isolates of Enterobacter, Citrobacter and indole-positive Proteus; however, this activity decreased markedly when the MIC determinations were carried out with a large inoculum size. A similar inoculum effect was observed with cefamandole, however, cefoxitin's activity was relatively unchanged at increased inoculum sizes. Human serum had a relatively small effect on the in vitro activity of cefazaflur.