scholarly journals In Vitro and Intracellular Activity of Imipenem Combined with Rifabutin and Avibactam against Mycobacterium abscessus

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Eva Le Run ◽  
Michel Arthur ◽  
Jean-Luc Mainardi
Keyword(s):  
Inhibitory Concentration ◽  
Mycobacterium Abscessus ◽  
Antibiotic Activity ◽  
Intracellular Bacteria ◽  
Triple Combination ◽  
Pulmonary Infections ◽  
Content Type ◽  
The Impact ◽  
Lactamase Inhibitor

ABSTRACT Repurposing drugs may be useful as an add-on in the treatment of Mycobacterium abscessus pulmonary infections, which are particularly difficult to cure. M. abscessus naturally produces a β-lactamase, BlaMAb, which is inhibited by avibactam. The recommended regimens include imipenem, which is hydrolyzed by BlaMAb and used without any β-lactamase inhibitor. Here, we determine whether the addition of rifabutin improves the activity of imipenem alone or in combination with avibactam against M. abscessus CIP104536. Rifabutin at 16 μg/ml was only bacteriostatic (MIC of 4 μg/ml) and was moderately synergistic in combination with imipenem (fractional inhibitory concentration [FIC] index of 0.38). Addition of rifabutin (16 μg/ml) moderately increased killing by a low (8 μg/ml) but not by a high (32 μg/ml) concentration of imipenem. Addition of avibactam (4 μg/ml) did not further increase killing by the former combination. In infected macrophages, rifabutin (16 μg/ml) increased the activity of imipenem at 8 and 32 μg/ml, achieving 3- and 100-fold reductions in the numbers of intracellular bacteria, respectively. Avibactam (16 μg/ml) improved killing by imipenem at 8 μg/ml. A 5-fold killing was obtained for a triple combination comprising avibactam (16 μg/ml) and therapeutically achievable doses of imipenem (8 μg/ml) and rifabutin (1 μg/ml). These results indicate that the imipenem-rifabutin combination should be further considered for the treatment of M. abscessus pulmonary infections in cystic fibrosis patients and that addition of a β-lactamase inhibitor might improve its efficacy. Mechanistically, the impact of BlaMAb inhibition by avibactam on antibiotic activity was assessed by comparing CIP104536 and a β-lactamase-deficient derivative.

scholarly journals In vitro and intracellular activity of imipenem combined with tedizolid, rifabutin, and avibactam against Mycobacterium abscessus

2018 ◽  
Author(s):  
Eva Le Run ◽  
Michel Arthur ◽  
Jean-Luc Mainardi
Keyword(s):  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Mycobacterium Abscessus ◽  
Pulmonary Infections ◽  
Once Daily ◽  
Minimal Inhibitory Concentrations ◽  
Recommended Treatment ◽  
The Impact ◽  
Lactamase Inhibitor

Mycobacterium abscessus has emerged as a significant pathogen responsible for chronic pulmonary infections in cystic fibrosis (CF) patients, which are difficult to treat due to resistance to a broad range of antibiotics. The initial phase of the recommended treatment in CF patients includes imipenem used without any β-lactamase inhibitor in spite of the production of the β-lactamase BlaMab. Here, we determine whether the addition of tedizolid, a once-daily oxazolidinone, improves the activity of imipenem alone or in combination with a β-lactamase inhibitor, avibactam, and rifabutin.The activity of the drugs was evaluated against M. abscessus CIP104536 by determining in vitro and intracellular antibacterial activities. The impact of BlaMab inhibition by avibactam on antibiotic activity was assessed by comparing CIP104536 and its β-lactamase-deficient derivative (ΔblaMab).The minimal inhibitory concentrations (MICs) of tedizolid against M. abscessus CIP104536 and ΔblaMab were 4 μg/mL. Tedizolid combined with imipenem showed a moderate synergistic effect with fractional inhibitory concentration (FIC) indexes of 0.41 and 0.38 for CIP104536 and ΔblaMab, respectively. For both strains, the addition of tedizolid at 2 μg/mL, corresponding to the peak serum concentration, increased the intracellular efficacy of imipenem at 8 and 32 μg/mL. Addition of avibactam and rifabutin improved the activity of the imipenem-tedizolid combination against CIP104536S.The imipenem-tedizolid combination should be further considered for the treatment of M. abscessus pulmonary infections in CF patients. The efficacy of the treatment might benefit from the use of a β-lactamase inhibitor, such as avibactam, and the addition of rifabutin.

scholarly journals Inhibition of the β-Lactamase BlaMab by Avibactam Improves the In Vitro and In Vivo Efficacy of Imipenem against Mycobacterium abscessus

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Anne-Laure Lefebvre ◽  
Vincent Le Moigne ◽  
Audrey Bernut ◽  
Carole Veckerlé ◽  
Fabrice Compain ◽  
...  
Keyword(s):  
Survival Rates ◽  
Mycobacterium Abscessus ◽  
Zebrafish Embryos ◽  
Bacterial Survival ◽  
Triple Combination ◽  
Content Type ◽  
The Impact ◽  
Lactamase Inhibitor

ABSTRACT Mycobacterium abscessus pulmonary infections are treated with a macrolide (clarithromycin or azithromycin), an aminoglycoside (amikacin), and a β-lactam (cefoxitin or imipenem). The triple combination is used without any β-lactamase inhibitor, even though M. abscessus produces the broad-spectrum β-lactamase BlaMab. We determine whether inhibition of BlaMab by avibactam improves the activity of imipenem against M. abscessus. The bactericidal activity of drug combinations was assayed in broth and in human macrophages. The in vivo efficacy of the drugs was tested by monitoring the survival of infected zebrafish embryos. The level of BlaMab production in broth and in macrophages was compared by quantitative reverse transcription-PCR and Western blotting. The triple combination of imipenem (8 or 32 μg/ml), amikacin (32 μg/ml), and avibactam (4 μg/ml) was bactericidal in broth (<0.1% survival), with 3.2- and 4.3-log10 reductions in the number of CFU being achieved at 72 h when imipenem was used at 8 and 32 μg/ml, respectively. The triple combination achieved significant intracellular killing, with the bacterial survival rates being 54% and 7% with the low (8 μg/ml) and high (32 μg/ml) dosages of imipenem, respectively. In vivo inhibition of BlaMab by avibactam improved the survival of zebrafish embryos treated with imipenem. Expression of the gene encoding BlaMab was induced (20-fold) in the infected macrophages. Inhibition of BlaMab by avibactam improved the efficacy of imipenem against M. abscessus in vitro, in macrophages, and in zebrafish embryos, indicating that this β-lactamase inhibitor should be clinically evaluated. The in vitro evaluation of imipenem may underestimate the impact of BlaMab, since the production of the β-lactamase is inducible in macrophages.

scholarly journals Select β-Lactam Combinations Exhibit Synergy againstMycobacterium abscessus In Vitro

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Elizabeth Story-Roller ◽  
Emily C. Maggioncalda ◽  
Gyanu Lamichhane
Keyword(s):  
Treatment Options ◽  
Unmet Need ◽  
Mycobacterium Abscessus ◽  
Nontuberculous Mycobacterium ◽  
Pulmonary Infections ◽  
Content Type ◽  
Resistant Mutants ◽  
Lactamase Inhibitor ◽  
Selection Of

ABSTRACTMycobacterium abscessusis a nontuberculous mycobacterium that causes invasive pulmonary infections in patients with structural lung disease.M. abscessusis intrinsically resistant to several classes of antibiotics, and an increasing number of strains isolated from patients exhibit resistance to most antibiotics considered for treatment of infections by this mycobacterium. Therefore, there is an unmet need for new regimens with improved efficacy to treat this disease. Synthesis of the essential cell wall peptidoglycan inM. abscessusis achieved via two enzyme classes,l,d- andd,d-transpeptidases, with each class preferentially inhibited by different subclasses of β-lactam antibiotics. We hypothesized that a combination of two β-lactams that comprehensively inhibit the two enzyme classes will exhibit synergy in killingM. abscessus. Paired combinations of antibiotics tested forin vitrosynergy againstM. abscessusincluded dual β-lactams, a β-lactam and a β-lactamase inhibitor, and a β-lactam and a rifamycin. Of the initial 206 combinations screened, 24 pairs exhibited synergy. A total of 13/24 pairs were combinations of two β-lactams, and 12/24 pairs brought the MICs of both drugs to within the therapeutic range. Additionally, synergistic drug pairs significantly reduced the frequency of selection of spontaneous resistant mutants. These novel combinations of currently available antibiotics may offer viable immediate treatment options against highly-resistantM. abscessusinfections.

scholarly journals Impact of relebactam-mediated inhibition of Mycobacterium abscessus BlaMab β-lactamase on the in vitro and intracellular efficacy of imipenem

2019 ◽  
Author(s):  
Eva Le Run ◽  
Heiner Atze ◽  
Michel Arthur ◽  
Jean-Luc Mainardi
Keyword(s):  
Second Generation ◽  
Antibacterial Activities ◽  
Mycobacterium Abscessus ◽  
Pulmonary Infections ◽  
Human Macrophages ◽  
Time Kill ◽  
The Impact ◽  
Intracellular Proliferation ◽  
Lactamase Inhibitor

Abstract Objectives Imipenem is one of the recommended β-lactams for the treatment of Mycobacterium abscessus pulmonary infections in spite of the production of BlaMab β-lactamase. Avibactam, a second-generation β-lactamase inhibitor, was previously shown to inactivate BlaMab, but its partner drug, ceftazidime, is devoid of any antibacterial activity against M. abscessus. Here, we investigate whether relebactam, a novel second-generation inhibitor developed in combination with imipenem, improves the activity of this carbapenem against M. abscessus. Methods The impact of BlaMab inhibition by relebactam was evaluated by determining MICs, time–kill curves and M. abscessus intracellular proliferation in human macrophages. Kinetic parameters for the inhibition of BlaMab by relebactam were determined by spectrophotometry using nitrocefin as the substrate. The data were compared with those obtained with avibactam. Results Combination of relebactam (4 mg/L) with β-lactams led to >128- and 2-fold decreases in the MICs of amoxicillin (from >4096 to 32 mg/L) and imipenem (from 8 to 4 mg/L). In vitro, M. abscessus was not killed by the imipenem/relebactam combination. In contrast, relebactam increased the intracellular activity of imipenem, leading to 88% killing. Relebactam and avibactam similarly potentiated the antibacterial activities of β-lactams although BlaMab was inactivated 150-fold less effectively by relebactam than by avibactam. Conclusions Inhibition of BlaMab by relebactam improves the efficacy of imipenem against M. abscessus in macrophages, indicating that the imipenem/relebactam combination should be clinically considered for the treatment of infections due to M. abscessus.

scholarly journals Rifabutin Acts in Synergy and Is Bactericidal with FrontlineMycobacterium abscessusAntibiotics Clarithromycin and Tigecycline, Suggesting a Potent Treatment Combination

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Mark Pryjma ◽  
Ján Burian ◽  
Charles J. Thompson
Keyword(s):  
Treatment Options ◽  
Multidrug Resistant ◽  
Current Treatment ◽  
Mycobacterium Abscessus ◽  
Triple Combination ◽  
Pulmonary Infections ◽  
Treatment Combination ◽  
Content Type ◽  
Current Treatment Regimen ◽  
Drug Regimens

ABSTRACTMycobacterium abscessusis a rapidly emerging mycobacterial pathogen causing dangerous pulmonary infections. Because these bacteria are intrinsically multidrug resistant, treatment options are limited and have questionable efficacy. The current treatment regimen relies on a combination of antibiotics, including clarithromycin paired with amikacin and either imipenem or cefoxitin. Tigecycline may be added when triple therapy is ineffective. We initially screened a library containing the majority of clinically available antibiotics for anti-M. abscessusactivity. The screen identified rifabutin, which was then investigated for its interactions withM. abscessusantibiotics used in drug regimens. Combination of rifabutin with either clarithromycin or tigecycline generated synergistic anti-M. abscessusactivity, dropping the rifabutin MIC below concentrations found in the lung. Importantly, these combinations generated bactericidal activity. The triple combination of clarithromycin, tigecycline, and rifabutin was also synergistic, and clinically relevant concentrations had a sterilizing effect onM. abscessuscultures. We suggest that combinations including rifabutin should be further investigated for treatment ofM. abscessuspulmonary infections.

scholarly journals Verapamil Improves the Activity of Bedaquiline against Mycobacterium abscessus In Vitro and in Macrophages

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Albertus Viljoen ◽  
Clément Raynaud ◽  
Matt D. Johansen ◽  
Françoise Roquet-Banères ◽  
Jean-Louis Herrmann ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Adjunctive Therapy ◽  
Mycobacterium Abscessus ◽  
Pulmonary Infections ◽  
Content Type ◽  
Resistant Strains ◽  
High Doses ◽  
Clinical Potential

ABSTRACT Due to intrinsic multidrug resistance, pulmonary infections with Mycobacterium abscessus are extremely difficult to treat. Previously, we demonstrated that bedaquiline is highly effective against Mycobacterium abscessus both in vitro and in vivo. Here, we report that verapamil improves the efficacy of bedaquiline activity against M. abscessus clinical isolates and low-level resistant strains, both in vitro and in macrophages. Verapamil may have clinical potential as adjunctive therapy provided that sufficiently high doses can be safely achieved.

scholarly journals Bedaquiline Inhibits the ATP Synthase in Mycobacterium abscessus and Is Effective in Infected Zebrafish

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Christian Dupont ◽  
Albertus Viljoen ◽  
Sangeeta Thomas ◽  
Françoise Roquet-Banères ◽  
Jean-Louis Herrmann ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Multidrug Resistant ◽  
Mycobacterium Abscessus ◽  
Nucleotide Polymorphisms ◽  
Pulmonary Infections ◽  
Zebrafish Model ◽  
Content Type ◽  
Short Period

ABSTRACT Pulmonary infections caused by Mycobacterium abscessus are emerging as a global threat, especially in cystic fibrosis patients. Further intensifying the concern of M. abscessus infection is the recent evidence of human-to-human transmission of the infection. M. abscessus is a naturally multidrug-resistant fast-growing pathogen for which pharmacological options are limited. Repurposing antitubercular drugs represents an attractive option for the development of chemotherapeutic alternatives against M. abscessus infections. Bedaquiline (BDQ), an ATP synthase inhibitor, has recently been approved for the treatment of multidrug-resistant tuberculosis. Herein, we show that BDQ has a very low MIC against a vast panel of clinical isolates. Despite being bacteriostatic in vitro, BDQ was highly efficacious in a zebrafish model of M. abscessus infection. Remarkably, a very short period of treatment was sufficient to protect the infected larvae from M. abscessus-induced killing. This was corroborated with reduced numbers of abscesses and cords, considered to be major pathophysiological signs in infected zebrafish. Mode-of-action studies revealed that BDQ triggered a rapid depletion of ATP in M. abscessus in vitro, consistent with the drug targeting the FoF1 ATP synthase. Importantly, despite a failure to select in vitro for spontaneous mutants that are highly resistant to BDQ, the transfer of single nucleotide polymorphisms leading to D29V or A64P substitutions in atpE conferred high resistance, thus resolving the target of BDQ in M. abscessus. Overall, this study indicates that BDQ is active against M. abscessus in vitro and in vivo and should be considered for clinical use against the difficult-to-manage M. abscessus pulmonary infections.

scholarly journals Pharmacokinetics-Pharmacodynamics of Tazobactam in Combination with Piperacillin in anIn VitroInfection Model

2016 ◽  
Vol 60 (4) ◽  
pp. 2075-2080 ◽  
Author(s):  
Anthony M. Nicasio ◽  
Brian D. VanScoy ◽  
Rodrigo E. Mendes ◽  
Mariana Castanheira ◽  
Catharine C. Bulik ◽  
...  
Keyword(s):  
Genetically Engineered ◽  
Dose Fractionation ◽  
Infection Model ◽  
Content Type ◽  
Study Results ◽  
High Level ◽  
The Impact ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor

ABSTRACTWe have previously demonstrated the pharmacokinetic-pharmacodynamic (PK-PD) index best associated with the efficacy of tazobactam when used in combination with ceftolozane to be the percentage of the dosing interval during which tazobactam concentrations remained above a threshold value (%time>threshold). Using anin vitroinfection model and the same isogenic CTX-M-15-producingEscherichia colitriplet set genetically engineered to transcribe different levels ofblaCTX-M-15, herein we describe dose fractionation studies designed to evaluate the PK-PD index associated with tazobactam efficacy, when given in combination with piperacillin, and the impact of the presence of a different β-lactam agent, or differentblaCTX-M-15transcription levels, on the magnitude of the tazobactam PK-PD index necessary for efficacy. The recombinant strains demonstrated piperacillin MIC values of 128, >256, and >256 μg/ml for the low-, moderate-, and high-level CTX-M-15-producingE. colistrains, respectively. The MIC value for piperacillin in the presence of 4 μg/ml of tazobactam was 2 μg/ml for all three strains. The PK-PD index associated with tazobactam efficacy was confirmed to be %time>threshold, regardless of β-lactamase transcription (r2= 0.839). The tazobactam concentration thresholds, however, changed with the CTX-M-15 transcription level and were 0.25, 0.5, and 2 μg/ml for the low-, moderate-, and high-level CTX-M-15-producing strains, respectively (r2= 0.921, 0.773, and 0.875, respectively). The %time>threshold values for tazobactam necessary for net bacterial stasis and a 1- and 2-log10-unit CFU/ml decrease from baseline at 24 h were 44.9, 62.9, and 84.9%, respectively. In addition to verifying our previous study results, these results also demonstrated that the magnitude of bacterial-cell killing associated with a β-lactam–β-lactamase inhibitor combination is dependent on the amount of β-lactamase produced. These data provide important information for the development of β-lactam–β-lactamase inhibitor combination agents.

scholarly journals Potency of Vaborbactam Is Less Affected than That of Avibactam in Strains Producing KPC-2 Mutations That Confer Resistance to Ceftazidime-Avibactam

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Ruslan Tsivkovski ◽  
Olga Lomovskaya
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Fold Increase ◽  
Clinical Settings ◽  
Bacterial Cells ◽  
Wild Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Lactamase Inhibitor

ABSTRACT Resistance to ceftazidime-avibactam due to mutations in KPC genes has been reported both in vitro and in clinical settings. The most frequently reported mutation leads to the amino acid substitution D179Y in the Ω loop of the enzyme. Bacterial cells that carry mutant KPC acquire a higher level of ceftazidime resistance, become more sensitive to other cephalosporins, and almost completely lose resistance to carbapenems. In this study, we demonstrated that two substitutions in KPC-2, D179Y and L169P, reduce the ability of avibactam to enhance the activity of ceftazidime, cefepime, or piperacillin against isogenic efflux-deficient strains of Pseudomonas aeruginosa, 8- to 32-fold and 4- to 16-fold for the D179Y and L169P variants, respectively, depending on the antibiotic. In contrast, the potency of vaborbactam, the structurally unrelated β-lactamase inhibitor that was recently approved by the FDA in combination with meropenem, is reduced no more than 2-fold. Experiments with purified enzymes demonstrate that the D179Y substitution causes an ∼20-fold increase in the 50% inhibitory concentration (IC50) for inhibition of ceftazidime hydrolysis by avibactam, versus 2-fold for vaborbactam, and that the L169P substitution has an ∼4.5-fold-stronger effect on the affinity for avibactam than for vaborbactam. In addition, the D179Y and L169P variants hydrolyze ceftazidime with 10-fold and 4-fold-higher efficiencies, respectively, than that of wild-type KPC-2. Thus, microbiological and biochemical experiments implicate both decreased ability of avibactam to interact with KPC-2 variants and an increase in the efficiency of ceftazidime hydrolysis in resistance to ceftazidime-avibactam. These substitutions have a considerably lesser effect on interactions with vaborbactam, making the meropenem-vaborbactam combination a valuable agent in managing infections due to KPC-producing carbapenem-resistant Enterobacteriaceae.

scholarly journals In Vitro and Intracellular Activity of Imipenem Combined with Tedizolid, Rifabutin, and Avibactam against Mycobacterium abscessus

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Eva Le Run ◽  
Michel Arthur ◽  
Jean-Luc Mainardi
Keyword(s):  
Serum Concentration ◽  
Synergistic Effect ◽  
Bactericidal Activity ◽  
Concentration Index ◽  
Inhibitory Concentration ◽  
Mycobacterium Abscessus ◽  
Fractional Inhibitory Concentration ◽  
Content Type ◽  
Fractional Inhibitory Concentration Index

ABSTRACT Mycobacterium abscessus infections are difficult to treat because of their resistance to many antibiotics. In vitro, tedizolid combined with imipenem displayed a moderate synergistic effect (fractional inhibitory concentration index, 0.41) but no bactericidal activity. Intracellularly, tedizolid 2 μg/ml (half of the MIC), corresponding to the peak serum concentration, increased the efficacy of imipenem at 8 and 32 μg/ml. Addition of avibactam and rifabutin, alone or in combination, improved the activity of the imipenem-tedizolid combination.

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