scholarly journals Antagonism of Azole Activity against Candida albicans following Induction of Multidrug Resistance Genes by Selected Antimicrobial Agents

1999 ◽  
Vol 43 (8) ◽  
pp. 1968-1974 ◽  
Author(s):  
Karl W. Henry ◽  
M. Cristina Cruz ◽  
Santosh K. Katiyar ◽  
Thomas D. Edlind
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Agents ◽  
Fold Increase ◽  
Antagonistic Effect ◽  
General Mechanism ◽  
Drug Induced ◽  
Genes Encoding ◽  
Efflux Proteins

ABSTRACT Antifungal azoles (e.g., fluconazole) are widely used for prophylaxis or treatment of Candida albicans infections in immunocompromised individuals, such as those with AIDS. These individuals are frequently treated with a variety of additional antimicrobial agents. Potential interactions between three azoles and 16 unrelated drugs (antiviral, antibacterial, antifungal, and antiprotozoal agents) were examined in vitro. Two compounds, tested at concentrations achievable in serum, demonstrated an antagonistic effect on azole activity against C. albicans. At fluconazole concentrations two to four times the 50% inhibitory concentration,C. albicans growth (relative to treatment with fluconazole alone) increased 3- to 18-fold in the presence of albendazole (2 μg/ml) or sulfadiazine (50 μg/ml). Antagonism (3- to 78-fold) of ketoconazole and itraconazole activity by these compounds was also observed. Since azole resistance has been correlated with overexpression of genes encoding efflux proteins, we hypothesized that antagonism results from drug-induced overexpression of these same genes. Indeed, brief incubation of C. albicans with albendazole or sulfadiazine resulted in a 3-to->10-fold increase in RNAs encoding multidrug transporter Cdr1p or Cdr2p. Zidovudine, trimethoprim, and isoniazid, which were not antagonistic with azoles, did not induce these RNAs. Fluphenazine, a known substrate for Cdr1p and Cdr2p, strongly induced their RNAs and, consistent with our hypothesis, strongly antagonized azole activity. Finally, antagonism was shown to require a functional Cdr1p. The possibility that azole activity against C. albicans is antagonized in vivo as well as in vitro in the presence of albendazole and sulfadiazine warrants investigation. Drug-induced overexpression of efflux proteins represents a new and potentially general mechanism for drug antagonism.

scholarly journals Candida albicans Quorum Sensing Molecules Stimulate Mouse Macrophage Migration

2015 ◽  
Vol 83 (10) ◽  
pp. 3857-3864 ◽  
Author(s):  
Jessica C. Hargarten ◽  
Tyler C. Moore ◽  
Thomas M. Petro ◽  
Kenneth W. Nickerson ◽  
Audrey L. Atkin
Keyword(s):  
Candida Albicans ◽  
Fungal Pathogens ◽  
Physiological Mechanism ◽  
Fold Increase ◽  
Immune Recognition ◽  
Macrophage Migration ◽  
Content Type ◽  
Transplant Patients

The polymorphic commensal fungusCandida albicanscauses life-threatening disease via bloodstream and intra-abdominal infections in immunocompromised and transplant patients. Although host immune evasion is a common strategy used by successful human fungal pathogens,C. albicansprovokes recognition by host immune cells less capable of destroying it. To accomplish this,C. albicanswhite cells secrete a low-molecular-weight chemoattractive stimulant(s) of macrophages, a phagocyte that they are able to survive within and eventually escape from.C. albicansopaque cells do not secrete this chemoattractive stimulant(s). We report here a physiological mechanism that contributes to the differences in the interaction ofC. albicanswhite and opaque cells with macrophages.E,E-Farnesol, which is secreted by white cells only, is a potent stimulator of macrophage chemokinesis, whose activity is enhanced by yeast cell wall components and aromatic alcohols.E,E-farnesol results in up to an 8.5-fold increase in macrophage migrationin vitroand promotes a 3-fold increase in the peritoneal infiltration of macrophagesin vivo. Therefore, modulation of farnesol secretion to stimulate host immune recognition by macrophages may help explain why this commensal is such a successful pathogen.

scholarly journals Identification of novel diphenyl urea inhibitors of Mt-GuaB2 active against Mycobacterium tuberculosis

Microbiology ◽  
2011 ◽  
Vol 157 (1) ◽  
pp. 290-299 ◽  
Author(s):  
Veeraraghavan Usha ◽  
Sudagar S. Gurcha ◽  
Andrew L. Lovering ◽  
Adrian J. Lloyd ◽  
Athina Papaemmanouil ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Genomic Sequence ◽  
Fold Increase ◽  
Inosine Monophosphate Dehydrogenase ◽  
Inosine Monophosphate ◽  
Genes Encoding ◽  
In Trans

In contrast with most bacteria, which harbour a single inosine monophosphate dehydrogenase (IMPDH) gene, the genomic sequence of Mycobacterium tuberculosis H37Rv predicts three genes encoding IMPDH: guaB1, guaB2 and guaB3. These three genes were cloned and expressed in Escherichia coli to evaluate functional IMPDH activity. Purified recombinant Mt-GuaB2, which uses inosine monophosphate as a substrate, was identified as the only active GuaB orthologue in M. tuberculosis and showed optimal activity at pH 8.5 and 37 °C. Mt-GuaB2 was inhibited significantly in vitro by a panel of diphenyl urea-based derivatives, which were also potent anti-mycobacterial agents against M. tuberculosis and Mycobacterium smegmatis, with MICs in the range of 0.2–0.5 μg ml−1. When Mt-GuaB2 was overexpressed on a plasmid in trans in M. smegmatis, a diphenyl urea analogue showed a 16-fold increase in MIC. Interestingly, when Mt-GuaB orthologues (Mt-GuaB1 and 3) were also overexpressed on a plasmid in trans in M. smegmatis, they also conferred resistance, suggesting that although these Mt-GuaB orthologues were inactive in vitro, they presumably titrate the effect of the inhibitory properties of the active compounds in vivo.

A Heparin Analogue that Releases Endogenous Heparan Sulphate

1979 ◽  
Author(s):  
D.P. Thomas ◽  
T.W. Barrowcliffe ◽  
E.A. Johnson ◽  
J. Stocks ◽  
J. Dawes ◽  
...  
Keyword(s):  
Lipoprotein Lipase ◽  
Specific Activity ◽  
Anticoagulant Activity ◽  
Heparan Sulphate ◽  
Factor Xa ◽  
Fold Increase ◽  
Endothelial Lining ◽  
Drug Induced

Heparan sulphate (HS), a near-relative of heparin, but with much less anticoagulant activity in vitro, is bound to cell surfaces. We examined HS isolated from porcine intestinal mucosa, and found that although the material had low anticoagulant activity by APTT, it had a marked effect in anti-Factor Xa clotting assays, giving anti-Xa/APTT ratios of approximately 4:1 in terms of specific activity. In crossed immunoelectrophoresis experiments, HS bound to antithrombin III, but at higher concentrations than heparin. A heparin analogue (a polysulphated chondroitin), while virtually inactive in vitro, nevertheless when administered s.c. to man potentiated the effect of anti-Factor Xa to an extent comparable to that produced by low-dose heparin, but with an anti-Xa/APTT ratio of 4:1. The analogue also produced a marked release of lipoprotein lipase and a four-fold increase in the level of circulating PF4, as measured by radioimmunoassay. The anti-Xa and APTT effects of HS in vitro are very similar to those produced by the analogue in vivo, and it is suggested that the analogue releases not only lipoprotein lipase and PF4, but also HS. The drug-induced release of an endogenous glycosamino-glycan (probably from the endothelial lining of vessels) with anti-Xa activity may represent a fruitful approach to the prophylaxis of venous thrombosis.

scholarly journals Potent Synergism of the Combination of Fluconazole and Cyclosporine in Candida albicans

2000 ◽  
Vol 44 (9) ◽  
pp. 2373-2381 ◽  
Author(s):  
Oscar Marchetti ◽  
Philippe Moreillon ◽  
Michel P. Glauser ◽  
Jacques Bille ◽  
Dominique Sanglard
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Agents ◽  
Management Strategies ◽  
Growth Control ◽  
Platelet Aggregation Inhibitors ◽  
Microtiter Plate ◽  
Antiarrhythmic Agents ◽  
Antifungal Effect

ABSTRACT Several types of drugs currently used in clinical practice were screened in vitro for their potentiation of the antifungal effect of the fungistatic agent fluconazole (FLC) on Candida albicans. These drugs included inhibitors of multidrug efflux transporters, antimicrobial agents, antifungal agents, and membrane-active compounds with no antimicrobial activity, such as antiarrhythmic agents, proton pump inhibitors, and platelet aggregation inhibitors. Among the drugs tested in an agar disk diffusion assay, cyclosporine (Cy), which had no intrinsic antifungal activity, showed a potent antifungal effect in combination with FLC. In a checkerboard microtiter plate format, however, it was observed that the MIC of FLC, as classically defined by the NCCLS recommendations, was unchanged when FLC and Cy were combined. Nevertheless, if a different reading endpoint corresponding to the minimal fungicidal concentration needed to decrease viable counts by at least 3 logs in comparison to the growth control was chosen, the combination was synergistic (fractional inhibitory concentration index of <1). This endpoint fitted to the definition of MIC-0 (optically clear wells) and reflected the absence of the trailing effect, which is the result of a residual growth at FLC concentrations greater than the MIC. The MIC-0 values of FLC and Cy tested alone in C. albicans were >32 and >10 μg/ml, respectively, and decreased to 0.5 and 0.625 μg/ml when the two drugs were combined. The combination of 0.625 μg of Cy per ml with supra-MICs of FLC resulted in a potent antifungal effect in time-kill curve experiments. This effect was fungicidal or fungistatic, depending on the C. albicans strain used. Since the Cy concentration effective in vitro is achievable in vivo, the combination of this agent with FLC represents an attractive perspective for the development of new management strategies for candidiasis.

Synthesis of Novel 3(N,N-dialkylamino)alkyl/phenyl Substituted Thieno [2,3-d]pyrimidinones as H1-Anti-Histaminic and Antimicrobial Agents

2019 ◽  
Vol 15 (1) ◽  
pp. 63-70
Author(s):  
Shiv Dev Singh ◽  
Arvind Kumar ◽  
Firoz Babar ◽  
Neetu Sachan ◽  
Arun Kumar Sharma
Keyword(s):  
Antimicrobial Activity ◽  
Potassium Hydroxide ◽  
Antimicrobial Agents ◽  
Pyrimidine Ring ◽  
Antimicrobial Activities ◽  
Screening Methods ◽  
Chlorpheniramine Maleate ◽  
In Vivo Screening

Background: Thienopyrimidines are the bioisoster of quinazoline and unlike quinazoline exist in three isomeric forms corresponding to the three possible types annulation of thiophene to the pyrimidine ring viz thieno[2,3-d] pyrimidine, thieno[3,2-d] pyrimidine and thieno[3,4-d]pyrimidine. Heterocyclic containing the thienopyrimidinone moiety exhibits various pronounced activities such as anti-hypertensive, analgesic and anti-inflammatory, antiviral, platelet aggregation inhibitory, antiprotozoal bronchodilatory, phosphodiesterase inhibitory, antihistaminic, antipsychotic and antimicrobial activity. Objective: Synthesis of novel 3(N,N-dialkylamino)alkyl/phenyl substituted thieno[2,3-d]pyrimidinones as H1-anti-histaminic and antimicrobial agents. Methods: A series of 3-[(N,N-dialkylamino)alkyl/phenyl]-2-(1H)thioxo-5,6,7,8-tetrahydrobenzo(b) thieno(2,3-d)pyrimidine-4(3H)-ones[4a-d], their oxo analogous [5a-d] and 3-[(N,N-dialkylamino)alkyl]- 2-chlorophenyl-5,6,7,8-tetrahydrobenzo(b)thieno(2,3-d)pyrimidine- 4 (3H)-ones[6a-d]derivative were synthesized from 2-amino-4,5,6,7-tetrahydrobenzo(b)thiophene-3-carboxylic acid by nucleophilic substitution of different N,N-dialkyl alkylene/phenylene diamines on activated 3-acylchloride moiety followed by cyclocondensation with carbon disulfide and ethanolic potassium hydroxide to get [4a-d] and in second reaction by condensation with 4-chlorobenzoyl chloride to get [6a-d] by single pot novel innovative route. The oxo analogous [5a-d] were prepared by treating derivatives [4a-d] with potassium permagnate in ethanolic KOH. The synthesized compound were evaluated for H1-antihistaminic and antimicrobial activities. Results: All synthesized compounds exhibited significant H1-antihistaminic activity by in vitro and in vivo screening methods and data were verified analytically and statistically. The compound 4a, 4b, 5a and 5b showed significant H1-antihistaminiic activity than the reference standard chlorpheniramine maleate. The compound 6d, 6c, 5c and 4c exhibited significant antimicrobial activity.

scholarly journals Enhancement of hepatic 4-hydroxylation of 25-hydroxyvitamin D3through CYP3A4 induction in vitro and in vivo: Implications for drug-induced osteomalacia

2013 ◽  
Vol 28 (5) ◽  
pp. 1101-1116 ◽  
Author(s):  
Zhican Wang ◽  
Yvonne S Lin ◽  
Leslie J Dickmann ◽  
Emma-Jane Poulton ◽  
David L Eaton ◽  
...  
Keyword(s):  
Drug Induced ◽  
Cyp3a4 Induction

scholarly journals In vivo transcriptome analysis provides insights into host-dependent expression of virulence factors by Yersinia entomophaga MH96, during infection of Galleria mellonella

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Amber R Paulson ◽  
Maureen O’Callaghan ◽  
Xue-Xian Zhang ◽  
Paul B Rainey ◽  
Mark R H Hurst
Keyword(s):  
Galleria Mellonella ◽  
Functional Enrichment ◽  
Natural Environments ◽  
Insecticidal Toxin ◽  
Heat Stable ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Cell Densities

Abstract The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.

scholarly journals Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

2007 ◽  
Vol 6 (6) ◽  
pp. 931-939 ◽  
Author(s):  
Fang Li ◽  
Michael J. Svarovsky ◽  
Amy J. Karlsson ◽  
Joel P. Wagner ◽  
Karen Marchillo ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Cell Adhesion ◽  
Biofilm Formation ◽  
Fungal Infections ◽  
Gene Dosage ◽  
Venous Catheter ◽  
Flow Chamber ◽  
Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

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