Synergistic Effect of Antituberculosis Drugs and AzolesIn Vitroagainst Histoplasma capsulatum var. capsulatum

ABSTRACTThis study evaluatedin vitrointeractions of antituberculosis drugs and triazoles againstHistoplasma capsulatum. Nine drug combinations, each including an antituberculosis drug (isoniazid, pyrazinamide, or ethambutol) plus a triazole (itraconazole, fluconazole, or voriconazole), were tested against both growth forms ofH. capsulatum. Stronger synergistic interactions were seen in isoniazid or pyrazinamide plus triazoles for the mold form and ethambutol plus voriconazole for the yeast-like form. Further studies should evaluate these combinationsin vivo.

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Transcriptomic Signatures Predict Regulators of Drug Synergy and Clinical Regimen Efficacy against Tuberculosis

mBio ◽

10.1128/mbio.02627-19 ◽

2019 ◽

Vol 10 (6) ◽

Cited By ~ 6

Author(s):

Shuyi Ma ◽

Suraj Jaipalli ◽

Jonah Larkins-Ford ◽

Jenny Lohmiller ◽

Bree B. Aldridge ◽

...

Keyword(s):

Clinical Trials ◽

Computational Model ◽

Drug Combinations ◽

Broth Culture ◽

Multiple Drug ◽

Content Type ◽

Drug Synergy ◽

Drug Regimens

ABSTRACT The rapid spread of multidrug-resistant strains has created a pressing need for new drug regimens to treat tuberculosis (TB), which kills 1.8 million people each year. Identifying new regimens has been challenging due to the slow growth of the pathogen Mycobacterium tuberculosis (MTB), coupled with the large number of possible drug combinations. Here we present a computational model (INDIGO-MTB) that identified synergistic regimens featuring existing and emerging anti-TB drugs after screening in silico more than 1 million potential drug combinations using MTB drug transcriptomic profiles. INDIGO-MTB further predicted the gene Rv1353c as a key transcriptional regulator of multiple drug interactions, and we confirmed experimentally that Rv1353c upregulation reduces the antagonism of the bedaquiline-streptomycin combination. A retrospective analysis of 57 clinical trials of TB regimens using INDIGO-MTB revealed that synergistic combinations were significantly more efficacious than antagonistic combinations (P value = 1 × 10−4) based on the percentage of patients with negative sputum cultures after 8 weeks of treatment. Our study establishes a framework for rapid assessment of TB drug combinations and is also applicable to other bacterial pathogens. IMPORTANCE Multidrug combination therapy is an important strategy for treating tuberculosis, the world’s deadliest bacterial infection. Long treatment durations and growing rates of drug resistance have created an urgent need for new approaches to prioritize effective drug regimens. Hence, we developed a computational model called INDIGO-MTB that identifies synergistic drug regimens from an immense set of possible drug combinations using the pathogen response transcriptome elicited by individual drugs. Although the underlying input data for INDIGO-MTB was generated under in vitro broth culture conditions, the predictions from INDIGO-MTB correlated significantly with in vivo drug regimen efficacy from clinical trials. INDIGO-MTB also identified the transcription factor Rv1353c as a regulator of multiple drug interaction outcomes, which could be targeted for rationally enhancing drug synergy.

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Redundant Catalases Detoxify Phagocyte Reactive Oxygen and Facilitate Histoplasma capsulatum Pathogenesis

Infection and Immunity ◽

10.1128/iai.00173-13 ◽

2013 ◽

Vol 81 (7) ◽

pp. 2334-2346 ◽

Cited By ~ 35

Author(s):

Eric D. Holbrook ◽

Katherine A. Smolnycki ◽

Brian H. Youseff ◽

Chad A. Rappleye

Keyword(s):

Immune System ◽

Innate Immune System ◽

Histoplasma Capsulatum ◽

Reactive Oxygen ◽

Innate Immune ◽

Respiratory Pathogen ◽

Human Neutrophils ◽

Content Type

ABSTRACTHistoplasma capsulatumis a respiratory pathogen that infects phagocytic cells. The mechanisms allowingHistoplasmato overcome toxic reactive oxygen molecules produced by the innate immune system are an integral part ofHistoplasma's ability to survive during infection. To probe the contribution ofHistoplasmacatalases in oxidative stress defense, we created and analyzed the virulence defects of mutants lacking CatB and CatP, which are responsible for extracellular and intracellular catalase activities, respectively. Both CatB and CatP protectedHistoplasmafrom peroxide challengein vitroand from antimicrobial reactive oxygen produced by human neutrophils and activated macrophages. Optimal protection required both catalases, as the survival of a double mutant lacking both CatB and CatP was lower than that of single-catalase-deficient cells. Although CatB contributed to reactive oxygen species defensesin vitro, CatB was dispensable for lung infection and extrapulmonary disseminationin vivo. Loss of CatB from a strain also lacking superoxide dismutase (Sod3) did not further reduce the survival ofHistoplasmayeasts. Nevertheless, some catalase function was required for pathogenesis since simultaneous loss of both CatB and CatP attenuatedHistoplasmavirulencein vivo. These results demonstrate thatHistoplasma's dual catalases comprise a system that enablesHistoplasmato efficiently overcome the reactive oxygen produced by the innate immune system.

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Importance of Confirming Data on theIn VivoEfficacy of Novel Antibacterial Drug Regimens against Various Strains of Mycobacterium tuberculosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05701-11 ◽

2011 ◽

Vol 56 (2) ◽

pp. 731-738 ◽

Cited By ~ 22

Author(s):

Mary A. De Groote ◽

Veronica Gruppo ◽

Lisa K. Woolhiser ◽

Ian M. Orme ◽

Janet C. Gilliland ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Animal Studies ◽

Strain Difference ◽

Drug Combinations ◽

Antibacterial Drug ◽

Preclinical Testing ◽

Content Type ◽

Drug Regimens

ABSTRACTIn preclinical testing of antituberculosis drugs, laboratory-adapted strains ofMycobacterium tuberculosisare usually used both forin vitroandin vivostudies. However, it is unknown whether the heterogeneity ofM. tuberculosisstocks used by various laboratories can result in different outcomes in tests of antituberculosis drug regimens in animal infection models. In head-to-head studies, we investigated whether bactericidal efficacy results in BALB/c mice infected by inhalation with the laboratory-adapted strains H37Rv and Erdman differ from each other and from those obtained with clinical tuberculosis strains. Treatment of mice consisted of dual and triple drug combinations of isoniazid (H), rifampin (R), and pyrazinamide (Z). The results showed that not all strains gave the samein vivoefficacy results for the drug combinations tested. Moreover, the ranking of HRZ and RZ efficacy results was not the same for the two H37Rv strains evaluated. The magnitude of this strain difference also varied between experiments, emphasizing the risk of drawing firm conclusions for human trials based on single animal studies. The results also confirmed that the antagonism seen within the standard HRZ regimen by some investigators appears to be anM. tuberculosisstrain-specific phenomenon. In conclusion, the specific identity ofM. tuberculosisstrain used was found to be an important variable that can change the apparent outcome ofin vivoefficacy studies in mice. We highly recommend confirmation of efficacy results in late preclinical testing against a differentM. tuberculosisstrain than the one used in the initial mouse efficacy study, thereby increasing confidence to advance potent drug regimens to clinical trials.

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Investigation of the Efficacy of Micafungin in the Treatment of Histoplasmosis Using Two North American Strains of Histoplasma capsulatum

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01681-10 ◽

2011 ◽

Vol 55 (9) ◽

pp. 4447-4450 ◽

Cited By ~ 15

Author(s):

Chadi A. Hage ◽

Patricia Connolly ◽

Daniel Horan ◽

Michelle Durkin ◽

Melinda Smedema ◽

...

Keyword(s):

Amphotericin B ◽

North American ◽

Liposomal Amphotericin ◽

Histoplasma Capsulatum ◽

Liposomal Amphotericin B ◽

Content Type ◽

Yeast Form

ABSTRACTMicafungin alone and combined with liposomal amphotericin B was evaluated against two strains ofHistoplasma capsulatum. Micafungin was activein vitroagainst the mold but not the yeast form but was ineffectivein vivo. Micafungin appears to be ineffective in treatment of histoplasmosis.

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Amphotericin B- and Voriconazole-Echinocandin Combinations against Aspergillus spp.: Effect of Serum on Inhibitory and Fungicidal Interactions

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00597-13 ◽

2013 ◽

Vol 57 (10) ◽

pp. 4656-4663 ◽

Cited By ~ 21

Author(s):

Antigoni Elefanti ◽

Johan W. Mouton ◽

Paul E. Verweij ◽

Athanassios Tsakris ◽

Loukia Zerva ◽

...

Keyword(s):

Amphotericin B ◽

Colorimetric Method ◽

Antifungal Drugs ◽

Content Type ◽

Synergistic Interactions ◽

Inhibitory Activities ◽

Additive Interactions ◽

Species Specific

ABSTRACTAntifungal combination therapy with voriconazole or amphotericin B and an echinocandin is often employed as primary or salvage therapy for management particularly of refractory aspergillosis. The pharmacodynamic interactions of amphotericin B- and voriconazole-based combinations with the three echinocandins caspofungin, micafungin, and anidulafungin in the presence of serum were tested against 15Aspergillus fumigatuscomplex,A. flavuscomplex, andA. terreuscomplex isolates to assess both their growth-inhibitory and fungicidal activities. Thein vitroactivity of each drug alone and in combination at a 1:1 fixed concentration ratio was tested with a broth microdilution colorimetric method, and interactions were assessed by isobolographic analysis. Synergy was found for all amphotericin B- and voriconazole-based combinations, with amphotericin B-based combinations showing strong inhibitory synergistic interactions (interaction indices of 0.20 to 0.52) and with voriconazole-based combinations demonstrating strong fungicidal synergistic interactions (interaction indices of 0.10 to 0.29) (P< 0.001). Drug- and species-specific differences were found, with caspofungin and theA. fumigatuscomplex exhibiting the weakest synergistic interactions. In the presence of serum, the synergistic interactions were reduced in the order (from largest to smallest decrease) micafungin > anidulafungin > caspofungin, andA. flavuscomplex >A. fumigatuscomplex >A. terreuscomplex, resulting in additive interactions, particularly for inhibitory activities of amphotericin B-echinocandin combinations and fungicidal activities of voriconazole-echinocandin combinations. Drug- and species-specific differences were found in the presence of serum for inhibitory activities of antifungal drugs, with the lowest interaction indices being observed for amphotericin B-caspofungin (median, 0.77) and for theA. terreuscomplex (median, 0.56). The presentin vitrodata showed that serum had a major impact on synergistic interactions of amphotericin B-echinocandin and voriconazole-echinocandin combinations, resulting in additive interactions and explaining the indifferent outcomes usually observedin vivo.

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Synergistic Interactions of Indole-2-Carboxamides and β-Lactam Antibiotics against Mycobacterium abscessus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02548-19 ◽

2020 ◽

Vol 64 (5) ◽

Cited By ~ 1

Author(s):

Clément Raynaud ◽

Wassim Daher ◽

Françoise Roquet-Banères ◽

Matt D. Johansen ◽

Jozef Stec ◽

...

Keyword(s):

Bactericidal Activity ◽

Mycobacterium Abscessus ◽

Drug Combinations ◽

New Drugs ◽

Addition Compound ◽

Content Type ◽

Synergistic Interactions ◽

New Drug ◽

Clinical Potential

ABSTRACT New drugs or therapeutic combinations are urgently needed against Mycobacterium abscessus. Previously, we demonstrated the potent activity of indole-2-carboxamides 6 and 12 against M. abscessus. We show here that these compounds act synergistically with imipenem and cefoxitin in vitro and increase the bactericidal activity of the β-lactams against M. abscessus. In addition, compound 12 also displays synergism with imipenem and cefoxitin within infected macrophages. The clinical potential of these new drug combinations requires further evaluation.

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Tigecycline and homoharringtonine synergistically target myeloid leukemia cells by inhibiting mitochondrial translation through mTOR/4EBP1 pathway

10.21203/rs.3.rs-42286/v1 ◽

2020 ◽

Author(s):

Haiyang Yang ◽

Chen Mei ◽

Li Ye ◽

Yanling Ren ◽

Hua Zhang ◽

...

Keyword(s):

Synergistic Effect ◽

Drug Combination ◽

Myeloid Leukemia ◽

Drug Combinations ◽

Translation Initiation Factor ◽

Initiation Factor ◽

Leukemia Cells ◽

Mitochondrial Translation

Abstract BackgroundTigecycline (TIG) is a tetracycline derivative antibiotic. Successive studies have shown that TIG is efficacious for the treatment of some solid tumors and hematological malignant diseases both in vivo and in vitro, and drug combinations appear to provide better inhibition. To explore new drug combinations for myeloid leukemia, we compared the differential combination efficacy of TIG with several anti-leukemia drugs, and explored the mechanisms of the combination of TIG and homoharringtonine (HHT) in myeloid leukemia cells both in vitro and in vivo.MethodsCell proliferation was assessed using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyph-enyl)-2-(4-sulfophenyl)-2H-tetrazolium) and CFU-GM (colony forming unit-granulocyte and macrophage) assays. Apoptosis was detected by flow cytometry. The combination of effects was confirmed in myeloid leukemia cells and tumor-bearing mouse model. The regulation of the AKT/mTOR (mammalian target of rapamycin)/4EBP1 (eukaryotic translation initiation factor 4E binding protein 1) pathway was assessed using a Western blot and immunohistochemistry.ResultsThe combination of TIG and HHT had a strong synergistic effect in myeloid leukemia cells. The use of the drug combination in vivo also effectively delayed myeloid tumor development in mice. The synergistic effect of this drug combination is likely to be achieved by inhibiting mitochondrial translation and down-regulating the AKT/mTOR/4EBP1 signaling pathway. Conclusion: The combination of TIG and HHT can synergistically enhance an anti-leukemia effect through downregulating anti-apoptotic proteins. Inhibiting mitochondrial translation through the AKT/mTOR/4EBP1 pathway might be an important mechanism.

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The Yeast-Phase Virulence Requirement for α-Glucan Synthase Differs among Histoplasma capsulatum Chemotypes

Eukaryotic Cell ◽

10.1128/ec.00214-10 ◽

2010 ◽

Vol 10 (1) ◽

pp. 87-97 ◽

Cited By ~ 52

Author(s):

Jessica A. Edwards ◽

Elizabeth A. Alore ◽

Chad A. Rappleye

Keyword(s):

Cell Wall ◽

Histoplasma Capsulatum ◽

Yeast Cells ◽

Dependent Manner ◽

Glucan Synthase ◽

Content Type ◽

I Factor ◽

Yeast Phase

ABSTRACTHistoplasma capsulatumstrains can be classified into two chemotypes based on cell wall composition. The cell wall of chemotype II yeast contains a layer of α-(1,3)-glucan that masks immunostimulatory β-(1,3)-glucans from detection by the Dectin-1 receptor on host phagocytes. This α-(1,3)-glucan cell wall component is essential for chemotype IIHistoplasmavirulence. In contrast, chemotype I yeast cells lack α-(1,3)-glucanin vitro, yet they remain fully virulentin vivo. Analysis of the chemotype I α-glucan synthase (AGS1) locus revealed a 2.7-kb insertion in the promoter region that diminishesAGS1expression. Nonetheless,AGS1mRNA can be detected during respiratory infection with chemotype I yeast, suggesting that α-(1,3)-glucan could be produced duringin vivogrowth despite its absencein vitro. To directly test whetherAGS1contributes to chemotype I strain virulence, we preventedAGS1function by RNA interference and by insertional mutation. Loss ofAGS1function in chemotype I does not impair the cytotoxicity ofags1(−) mutant yeast to cultured macrophages, nor does it affect the intracellular growth of yeast. In a murine model of histoplasmosis, theags1(−) chemotype I mutant strains show no defect in lung infection or in extrapulmonary dissemination. Together, these studies demonstrate thatAGS1expression is dispensable for chemotype I yeast virulence, in contrast to the case for chemotype II yeast. Despite the absence of cell wall α-(1,3)-glucan, chemotype I yeast can avoid detection by Dectin-1 in a growth stage-dependent manner. This suggests the production of a uniqueHistoplasmachemotype I factor that, at least partially, circumvents the α-(1,3)-glucan requirement for yeast virulence.

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Synergistic Interactions of MmpL3 Inhibitors with Antitubercular Compounds In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02399-16 ◽

2017 ◽

Vol 61 (4) ◽

Cited By ~ 34

Author(s):

Wei Li ◽

Andrea Sanchez-Hidalgo ◽

Victoria Jones ◽

Vinicius Calado Nogueira de Moura ◽

E. Jeffrey North ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Mycolic Acid ◽

Antituberculosis Drugs ◽

Content Type ◽

Synergistic Interactions ◽

Acid Transporter

ABSTRACT A number of inhibitors of the essential Mycobacterium tuberculosis mycolic acid transporter, MmpL3, are currently under development as potential novel antituberculosis agents. Using the checkerboard method to study the interaction profiles of various antituberculosis drugs or experimental compounds with two different chemotypes inhibiting this transporter (indolcarboxamides and adamantyl ureas), we showed that MmpL3 inhibitors act synergistically with rifampin, bedaquiline, clofazimine, and β-lactams.

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Synthesis of Artemiside and Its Effects in Combination with Conventional Drugs against Severe Murine Malaria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05006-11 ◽

2011 ◽

Vol 56 (1) ◽

pp. 163-173 ◽

Cited By ~ 19

Author(s):

Jin Guo ◽

Armand W. Guiguemde ◽

Annael Bentura-Marciano ◽

Julie Clark ◽

Richard K. Haynes ◽

...

Keyword(s):

Safety Margin ◽

Drug Combinations ◽

Parasite Development ◽

Content Type ◽

Drug Concentrations ◽

One Step ◽

High Concentrations ◽

Malaria Model

ABSTRACTThis research describes the use of novel antimalarial combinations of the new artemisinin derivative artemiside, a 10-alkylamino artemisinin. It is a stable, highly crystalline compound that is economically prepared from dihydroartemisinin in a one-step process. Artemiside activity was more pronounced than that of any antimalarial drug in use, both inPlasmodium falciparumculture andin vivoin a murine malaria model depicting cerebral malaria (CM).In vitrohigh-throughput testing of artemiside combinations revealed a large number of conventional antimalarial drugs with which it was additive. Following monotherapy in mice, individual drugs reduced parasitemias to nondetectable levels. However, after a period of latency, parasites again were seen and eventually all mice became terminally ill. Treatment with individual drugs did not prevent CM in mice with recrudescent malaria, except for piperaquine at high concentrations. Even when CM was prevented, the mice developed later of severe anemia. In contrast, most of the mice treated with drug combinations survived. A combination of artemiside and mefloquine or piperaquine may confer an optimal result because of the longer half life of both conventional drugs. The use of artemiside combinations revealed a significant safety margin of the effective artemiside doses. Likewise, a combination of 1.3 mg/kg of body weight artemiside and 10 mg/kg piperaquine administered for 3 days from the seventh day postinfection was completely curative. It appears possible to increase drug concentrations in the combination therapy without reaching toxic levels. Using the drug combinations as little as 1 day before the expected death of control animals, we could prevent further parasite development and death due to CM or anemic malaria. Earlier treatment may prevent cognitive dysfunctions which might occur after recovery from CM.

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