scholarly journals Developing Synergistic Drug Combinations To Restore Antibiotic Sensitivity in Drug-Resistant Mycobacterium tuberculosis

2021 ◽  
Vol 65 (5) ◽  
Author(s):  
Charles Omollo ◽  
Vinayak Singh ◽  
Elizabeth Kigondu ◽  
Antonina Wasuna ◽  
Pooja Agarwal ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Ex Vivo ◽  
Antibiotic Sensitivity ◽  
Infectious Agent ◽  
Drug Combinations ◽  
Major Facilitator Superfamily ◽  
Drug Resistant ◽  
Content Type

ABSTRACT Tuberculosis (TB) is a leading global cause of mortality owing to an infectious agent, accounting for almost one-third of antimicrobial resistance (AMR) deaths annually. We aimed to identify synergistic anti-TB drug combinations with the capacity to restore therapeutic efficacy against drug-resistant mutants of the causative agent, Mycobacterium tuberculosis. We investigated combinations containing the known translational inhibitors, spectinomycin (SPT) and fusidic acid (FA), or the phenothiazine, chlorpromazine (CPZ), which disrupts mycobacterial energy metabolism. Potentiation of whole-cell drug efficacy was observed in SPT-CPZ combinations. This effect was lost against an M. tuberculosis mutant lacking the major facilitator superfamily (MFS) efflux pump, Rv1258c. Notably, the SPT-CPZ combination partially restored SPT efficacy against an SPT-resistant mutant carrying a g1379t point mutation in rrs, encoding the mycobacterial 16S rRNA. Combinations of SPT with FA, which targets the mycobacterial elongation factor G, exhibited potentiating activity against wild-type M. tuberculosis. Moreover, this combination produced a modest potentiating effect against both FA-monoresistant and SPT-monoresistant mutants. Finally, combining SPT with the frontline anti-TB agents, rifampicin (RIF) and isoniazid, resulted in enhanced activity in vitro and ex vivo against both drug-susceptible M. tuberculosis and a RIF-monoresistant rpoB S531L mutant. These results support the utility of novel potentiating drug combinations in restoring antibiotic susceptibility of M. tuberculosis strains carrying genetic resistance to any one of the partner compounds.

scholarly journals Developing synergistic drug combinations to restore antibiotic sensitivity in drug-resistant Mycobacterium tuberculosis

2019 ◽  
Author(s):  
Charles Omollo ◽  
Vinayak Singh ◽  
Elizabeth Kigondu ◽  
Antonina Wasuna ◽  
Pooja Agarwal ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Ex Vivo ◽  
Genetic Resistance ◽  
Antibiotic Sensitivity ◽  
Infectious Agent ◽  
Drug Combinations ◽  
Major Facilitator Superfamily ◽  
Drug Resistant

ABSTRACTTuberculosis (TB) is a leading global cause of mortality owing to an infectious agent, accounting for almost one-third of antimicrobial resistance (AMR) deaths annually. We aimed to identify synergistic anti-TB drug combinations with the capacity to restore therapeutic efficacy against drug-resistant mutants of the causative agent, Mycobacterium tuberculosis. We investigated combinations containing the known translational inhibitors, spectinomycin (SPT) and fusidic acid (FA), or the phenothiazine, chlorpromazine (CPZ), which disrupts mycobacterial energy metabolism. Potentiation of whole-cell drug efficacy was observed in SPT-CPZ combinations. This effect was lost against an M. tuberculosis mutant lacking the major facilitator superfamily (MFS) efflux pump, Rv1258c. Notably, the SPT-CPZ combination restored SPT efficacy against an SPT-resistant mutant carrying a g1379t point mutation in rrs, encoding the mycobacterial 16S ribosomal RNA. Combinations of SPT with FA, which targets the mycobacterial elongation factor G, exhibited potentiating activity against wild-type M. tuberculosis. Moreover, this combination produced a marginal potentiating effect against both FA-monoresistant and SPT-monoresistant mutants. Finally, combining SPT with the frontline anti-TB agents, rifampicin (RIF) and isoniazid, resulted in enhanced activity in vitro and ex vivo against both drug-susceptible M. tuberculosis and a RIF-monoresistant rpoB S531L mutant.These results support the utility of novel potentiating drug combinations in restoring antibiotic susceptibility of M. tuberculosis strains carrying genetic resistance to any one of the partner compounds.

scholarly journals Efflux Attenuates the Antibacterial Activity of Q203 in Mycobacterium tuberculosis

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Jichan Jang ◽  
Ryangyeo Kim ◽  
Minjeong Woo ◽  
Jinsun Jeong ◽  
Da Eun Park ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Ex Vivo ◽  
Drug Candidate ◽  
Content Type ◽  
Tb Treatment ◽  
Pump Activity ◽  
Efflux Pump Inhibitors ◽  
Combinatorial Strategy

ABSTRACT New and improved treatments for tuberculosis (TB) are urgently needed. Recently, it has been demonstrated that verapamil, an efflux inhibitor, can reduce bacterial drug tolerance caused by efflux pump activity when administered in combination with available antituberculosis agents. The aim of this study was to evaluate the effectiveness of verapamil in combination with the antituberculosis drug candidate Q203, which has recently been developed and is currently under clinical trials as a potential antituberculosis agent. We evaluated changes in Q203 activity in the presence and absence of verapamil in vitro using the resazurin microplate assay and ex vivo using a microscopy-based phenotypic assay for the quantification of intracellular replicating mycobacteria. Verapamil increased the potency of Q203 against Mycobacterium tuberculosis both in vitro and ex vivo, indicating that efflux pumps are associated with the activity of Q203. Other efflux pump inhibitors also displayed an increase in Q203 potency, strengthening this hypothesis. Therefore, the combination of verapamil and Q203 may be a promising combinatorial strategy for anti-TB treatment to accelerate the elimination of M. tuberculosis.

scholarly journals Comparison of In Vitro Activity and MIC Distributions between the Novel Oxazolidinone Delpazolid and Linezolid against Multidrug-Resistant and Extensively Drug-Resistant Mycobacterium tuberculosis in China

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Zhaojing Zong ◽  
Wei Jing ◽  
Jin Shi ◽  
Shu'an Wen ◽  
Tingting Zhang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Novel Mutation ◽  
Multidrug Resistant ◽  
23S Rrna ◽  
Drug Resistant ◽  
Content Type ◽  
Extensively Drug Resistant ◽  
Significant Difference ◽  
Mdr Tb

ABSTRACT Oxazolidinones are efficacious in treating mycobacterial infections, including tuberculosis (TB) caused by drug-resistant Mycobacterium tuberculosis. In this study, we compared the in vitro activities and MIC distributions of delpazolid, a novel oxazolidinone, and linezolid against multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) in China. Additionally, genetic mutations in 23S rRNA, rplC, and rplD genes were analyzed to reveal potential mechanisms underlying the observed oxazolidinone resistance. A total of 240 M. tuberculosis isolates were included in this study, including 120 MDR-TB isolates and 120 XDR-TB isolates. Overall, linezolid and delpazolid MIC90 values for M. tuberculosis isolates were 0.25 mg/liter and 0.5 mg/liter, respectively. Based on visual inspection, we tentatively set epidemiological cutoff (ECOFF) values for MIC determinations for linezolid and delpazolid at 1.0 mg/liter and 2.0 mg/liter, respectively. Although no significant difference in resistance rates was observed between linezolid and delpazolid among XDR-TB isolates (P > 0.05), statistical analysis revealed a significantly greater proportion of linezolid-resistant isolates than delpazolid-resistant isolates within the MDR-TB group (P = 0.036). Seven (53.85%) of 13 linezolid-resistant isolates were found to harbor mutations within the three target genes. Additionally, 1 isolate exhibited an amino acid substitution (Arg126His) within the protein encoded by rplD that contributed to high-level resistance to linezolid (MIC of >16 mg/liter), compared to a delpazolid MIC of 0.25. In conclusion, in vitro susceptibility testing revealed that delpazolid antibacterial activity was comparable to that of linezolid. A novel mutation within rplD that endowed M. tuberculosis with linezolid, but not delpazolid, resistance was identified.

scholarly journals Correlates between Models of Virulence for Mycobacterium tuberculosis among Isolates of the Central Asian Lineage: a Case for Lysozyme Resistance Testing?

2015 ◽  
Vol 83 (6) ◽  
pp. 2213-2223 ◽  
Author(s):  
Claire Pardieu ◽  
Nicola Casali ◽  
Simon O. Clark ◽  
Richard Hooper ◽  
Ann Williams ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Ex Vivo ◽  
Resistance Testing ◽  
Snp Analysis ◽  
Single Nucleotide ◽  
Content Type ◽  
Differential Outcomes ◽  
Central Asian ◽  
Strain H37rv

Virulence factors (VFs) contribute to the emergence of new humanMycobacterium tuberculosisstrains, are lineage dependent, and are relevant to the development ofM. tuberculosisdrugs/vaccines. VFs were sought withinM. tuberculosislineage 3, which has the Central Asian (CAS) spoligotype. Three isolates were selected from clusters previously identified as dominant in London, United Kingdom. Strain-associated virulence was studied in guinea pig, monocyte-derived macrophage, and lysozyme resistance assays. Whole-genome sequencing, single nucleotide polymorphism (SNP) analysis, and a literature review contributed to the identification of SNPs of interest. The animal model revealed borderline differences in strain-associated pathogenicity.Ex vivo, isolate C72 exhibited statistically significant differences in intracellular growth relative to C6 and C14. SNP candidates inducing lower fitness levels included 123 unique nonsynonymous SNPs, including three located in genes (lysX,caeA, andponA2) previously identified as VFs in the laboratory-adapted reference strain H37Rv and shown to confer lysozyme resistance. C72 growth was most affected by lysozymein vitro. A BLAST search revealed that all three SNPs of interest (C35F, P76Q, and P780R) also occurred in Tiruvallur, India, and in Uganda. Unlike C72, however, no single isolate identified through BLAST carried all three SNPs simultaneously. CAS isolates representative of three medium-sized human clusters demonstrated differential outcomes in models commonly used to estimate strain-associated virulence, supporting the idea that virulence varies within, not just across,M. tuberculosislineages. Three VF SNPs of interest were identified in two additional locations worldwide, which suggested independent selection and supported a role for these SNPs in virulence. The relevance of lysozyme resistance to strain virulence remains to be established.

scholarly journals Transcriptional Profiling of Mycobacterium tuberculosis Exposed toIn VitroLysosomal Stress

2016 ◽  
Vol 84 (9) ◽  
pp. 2505-2523 ◽  
Author(s):  
Wenwei Lin ◽  
Paola Florez de Sessions ◽  
Garrett Hor Keong Teoh ◽  
Ahmad Naim Nazri Mohamed ◽  
Yuan O. Zhu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Efflux Pump ◽  
Metabolic Reprogramming ◽  
Human Macrophage ◽  
Host Immune System ◽  
Activated Macrophages ◽  
Intrinsic Resistance ◽  
Macrophage Infection ◽  
Content Type

Increasing experimental evidence supports the idea thatMycobacterium tuberculosishas evolved strategies to survive within lysosomes of activated macrophages. To further our knowledge ofM. tuberculosisresponse to the hostile lysosomal environment, we profiled the global transcriptional activity ofM. tuberculosiswhen exposed to the lysosomal soluble fraction (SF) prepared from activated macrophages. Transcriptome sequencing (RNA-seq) analysis was performed using various incubation conditions, ranging from noninhibitory to cidal based on the mycobacterial replication or killing profile. Under inhibitory conditions that led to the absence of apparent mycobacterial replication,M. tuberculosisexpressed a unique transcriptome with modulation of genes involved in general stress response, metabolic reprogramming, respiration, oxidative stress, dormancy response, and virulence. The transcription pattern also indicates characteristic cell wall remodeling with the possible outcomes of increased infectivity, intrinsic resistance to antibiotics, and subversion of the host immune system. Among the lysosome-specific responses, we identified theglgE-mediated 1,4 α-glucan synthesis pathway and a defined group of VapBC toxin/anti-toxin systems, both of which represent toxicity mechanisms that potentially can be exploited for killing intracellular mycobacteria. A meta-analysis including previously reported transcriptomic studies in macrophage infection andin vitrostress models was conducted to identify overlapping and nonoverlapping pathways. Finally, the Tap efflux pump-encoding geneRv1258cwas selected for validation. AnM. tuberculosis ΔRv1258cmutant was constructed and displayed increased susceptibility to killing by lysosomal SF and the antimicrobial peptide LL-37, as well as attenuated survival in primary murine macrophages and human macrophage cell line THP-1.

scholarly journals In Vitro Activity and MIC of Sitafloxacin against Multidrug-Resistant and Extensively Drug-Resistant Mycobacterium tuberculosis Isolated in Thailand

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Manoon Leechawengwongs ◽  
Therdsak Prammananan ◽  
Sarinya Jaitrong ◽  
Pamaree Billamas ◽  
Nampueng Makhao ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Critical Concentration ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Drug Resistant ◽  
Content Type ◽  
Extensively Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

ABSTRACT New fluoroquinolones (FQs) have been shown to be more active against drug-resistant Mycobacterium tuberculosis strains than early FQs, such as ofloxacin. Sitafloxacin (STFX) is a new fluoroquinolone with in vitro activity against a broad range of bacteria, including M. tuberculosis. This study aimed to determine the in vitro activity of STFX against all groups of drug-resistant strains, including multidrug-resistant M. tuberculosis (MDR M. tuberculosis), MDR M. tuberculosis with quinolone resistance (pre-XDR), and extensively drug-resistant (XDR) strains. A total of 374 drug-resistant M. tuberculosis strains were tested for drug susceptibility by the conventional proportion method, and 95 strains were randomly submitted for MIC determination using the microplate alamarBlue assay (MABA). The results revealed that all the drug-resistant strains were susceptible to STFX at a critical concentration of 2 μg/ml. Determination of the MIC90s of the strains showed different MIC levels; MDR M. tuberculosis strains had a MIC90 of 0.0625 μg/ml, whereas pre-XDR and XDR M. tuberculosis strains had identical MIC90s of 0.5 μg/ml. Common mutations within the quinolone resistance-determining region (QRDR) of gyrA and/or gyrB did not confer resistance to STFX, except that double mutations of GyrA at Ala90Val and Asp94Ala were found in strains with a MIC of 1.0 μg/ml. The results indicated that STFX had potent in vitro activity against all the groups of drug-resistant M. tuberculosis strains and should be considered a new repurposed drug for treatment of multidrug-resistant and extensively drug-resistant TB.

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

2011 ◽  
Vol 56 (2) ◽  
pp. 731-738 ◽  
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.

scholarly journals In VitroandIn VivoActivities of the Nitroimidazole TBA-354 against Mycobacterium tuberculosis

2014 ◽  
Vol 59 (1) ◽  
pp. 136-144 ◽  
Author(s):  
A. M. Upton ◽  
S. Cho ◽  
T. J. Yang ◽  
Y. Kim ◽  
Y. Wang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pharmacokinetic Profile ◽  
Multidrug Resistant ◽  
Phase Iii ◽  
Drug Resistant ◽  
Next Generation ◽  
Content Type ◽  
Resistant Tuberculosis

ABSTRACTNitroimidazoles are a promising new class of antitubercular agents. The nitroimidazo-oxazole delamanid (OPC-67683, Deltyba) is in phase III trials for the treatment of multidrug-resistant tuberculosis, while the nitroimidazo-oxazine PA-824 is entering phase III for drug-sensitive and drug-resistant tuberculosis. TBA-354 (SN31354[(S)-2-nitro-6-((6-(4-trifluoromethoxy)phenyl)pyridine-3-yl)methoxy)-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazine]) is a pyridine-containing biaryl compound with exceptional efficacy against chronic murine tuberculosis and favorable bioavailability in preliminary rodent studies. It was selected as a potential next-generation antituberculosis nitroimidazole following an extensive medicinal chemistry effort. Here, we further evaluate the pharmacokinetic properties and activity of TBA-354 againstMycobacterium tuberculosis. TBA-354 is narrow spectrum and bactericidalin vitroagainst replicating and nonreplicatingMycobacterium tuberculosis, with potency similar to that of delamanid and greater than that of PA-824. The addition of serum protein or albumin does not significantly alter this activity. TBA-354 maintains activity againstMycobacterium tuberculosisH37Rv isogenic monoresistant strains and clinical drug-sensitive and drug-resistant isolates. Spontaneous resistant mutants appear at a frequency of 3 × 10−7.In vitrostudies andin vivostudies in mice confirm that TBA-354 has high bioavailability and a long elimination half-life.In vitrostudies suggest a low risk of drug-drug interactions. Low-dose aerosol infection models of acute and chronic murine tuberculosis reveal time- and dose-dependentin vivobactericidal activity that is at least as potent as that of delamanid and more potent than that of PA-824. Its superior potency and pharmacokinetic profile that predicts suitability for once-daily oral dosing suggest that TBA-354 be studied further for its potential as a next-generation nitroimidazole.

scholarly journals Activity of Semi-Synthetic Mulinanes against MDR, Pre-XDR, and XDR Strains of Mycobacterium tuberculosis

Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 876
Author(s):  
María Alejandrina Martínez-González ◽  
Luis Manuel Peña-Rodríguez ◽  
Andrés Humberto Uc-Cachón ◽  
Jorge Bórquez ◽  
Mario J. Simirgiotis ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Infectious Agent ◽  
Vero Cells ◽  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
New Drugs ◽  
Drug Resistant ◽  
Adjuvant Effect ◽  
Extensively Drug Resistant

Tuberculosis causes more than 1.2 million deaths each year. Worldwide, it is the first cause of death by a single infectious agent. The emergence of drug-resistant strains has limited pharmacological treatment of the disease and today, new drugs are urgently needed. Semi-synthetic mulinanes have previously shown important activity against multidrug-resistant (MDR) Mycobacterium tuberculosis. In this investigation, a new set of semi-synthetic mulinanes were synthetized, characterized, and evaluated for their in vitro activity against three drug-resistant clinical isolates of M. tuberculosis: MDR, pre-extensively Drug-Resistant (pre-XDR), and extensively Drug-Resistant (XDR), and against the drug-susceptible laboratory reference strain H37Rv. Derivative 1a showed the best anti-TB activity (minimum inhibitory concentration [MIC] = 5.4 µM) against the susceptible strain and was twice as potent (MIC = 2.7 µM) on the MDR, pre-XDR, and XDR strains and also possessed a bactericidal effect. Derivative 1a was also tested for its anti-TB activity in mice infected with the MDR strain. In this case, 1a produced a significant reduction of pulmonary bacilli loads, six times lower than the control, when tested at 0.2536 mg/Kg. In addition, 1a demonstrated an adjuvant effect by shortening second-line chemotherapy. Finally, the selectivity index of >15.64 shown by 1a when tested on Vero cells makes this derivative an important candidate for future studies in the development of novel antitubercular agents.

scholarly journals Structure-Activity Relationships of Wollamide Cyclic Hexapeptides with Activity against Drug-Resistant and Intracellular Mycobacterium tuberculosis

2019 ◽  
Vol 63 (3) ◽  
Author(s):  
Zeinab G. Khalil ◽  
Timothy A. Hill ◽  
Luis M. De Leon Rodriguez ◽  
Rink-Jan Lohman ◽  
Huy N. Hoang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mammalian Cells ◽  
Antimycobacterial Activity ◽  
Drug Resistant ◽  
Amino Acid Residues ◽  
Content Type ◽  
Cyclic Hexapeptides ◽  
Rats And Mice

ABSTRACT Wollamides are cyclic hexapeptides, recently isolated from an Australian soil Streptomyces isolate, that exhibit promising in vitro antimycobacterial activity against Mycobacterium bovis Bacille Calmette Guérin without displaying cytotoxicity against a panel of mammalian cells. Here, we report the synthesis and antimycobacterial activity of 36 new synthetic wollamides, collated with all known synthetic and natural wollamides, to reveal structure characteristics responsible for in vitro growth-inhibitory activity against Mycobacterium tuberculosis (H37Rv, H37Ra, CDC1551, HN878, and HN353). The most potent antimycobacterial wollamides were those where residue VI d-Orn (wollamide B) was replaced by d-Arg (wollamide B1) or d-Lys (wollamide B2), with all activity being lost when residue VI was replaced by Gly, l-Arg, or l-Lys (wollamide B3). Substitution of other amino acid residues mainly reduced or ablated antimycobacterial activity. Significantly, whereas wollamide B2 was the most potent in restricting M. tuberculosis in vitro, wollamide B1 restricted M. tuberculosis intracellular burden in infected macrophages. Wollamide B1 synergized with pretomanid (PA-824) in inhibiting M. tuberculosis in vitro growth but did not antagonize prominent first- and second-line tuberculosis antibiotics. Furthermore, wollamide B1 exerted bactericidal activity against nonreplicating M. tuberculosis and impaired growth of multidrug- and extensively drug-resistant clinical isolates. In vivo pharmacokinetic profiles for wollamide B1 in rats and mice encourage further optimization of the wollamide pharmacophore for in vivo bioavailability. Collectively, these observations highlight the potential of the wollamide antimycobacterial pharmacophore.

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