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

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.

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

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkz433 ◽

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.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00623-18 ◽

2018 ◽

Vol 62 (8) ◽

Cited By ~ 15

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.

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Select β-Lactam Combinations Exhibit Synergy againstMycobacterium abscessus In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02613-18 ◽

2019 ◽

Vol 63 (4) ◽

Cited By ~ 15

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.

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02440-16 ◽

2017 ◽

Vol 61 (4) ◽

Cited By ~ 49

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.

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Select β-lactam combinations exhibit synergy against Mycobacterium abscessus in vitro

10.1101/522649 ◽

2019 ◽

Author(s):

Elizabeth Story-Roller ◽

Emily C. Maggioncalda ◽

Gyanu Lamichhane

Keyword(s):

Cell Wall ◽

Treatment Options ◽

Unmet Need ◽

Mycobacterium Abscessus ◽

Nontuberculous Mycobacterium ◽

Pulmonary Infections ◽

Resistant Mutants ◽

Lactamase Inhibitor ◽

Selection Of

ABSTRACTMycobacterium abscessus (Mab) is a nontuberculous mycobacterium that causes invasive pulmonary infections in patients with structural lung disease. Mab is 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 Mab infections. Therefore, there is an unmet need for new regimens with improved efficacy to treat this disease. Synthesis of the essential cell wall peptidoglycan in Mab is achieved via two enzyme classes, L,D- and D-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 killing Mab. Paired combinations of antibiotics tested for in vitro synergy against Mab included 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. 13/24 pairs were combinations of two β-lactams. 12/24 pairs brought the minimum inhibitory concentrations 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-resistant Mab infections.

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A Prospective Open-Label Multicentre Trial on the Use of 1 G, Once Daily Ceftriaxone in Lower Respiratory Tract Infections

Canadian Journal of Infectious Diseases ◽

10.1155/1994/421905 ◽

1994 ◽

Vol 5 (suppl c) ◽

pp. 3C-8C ◽

Cited By ~ 1

Author(s):

Donald E Low ◽

Lionel A Mandell

Keyword(s):

Respiratory Tract ◽

Treatment Failure ◽

Lower Respiratory Tract ◽

Study Drug ◽

Open Label ◽

In Vitro Susceptibility ◽

Once Daily ◽

Minimal Inhibitory Concentrations ◽

Tract Infections

This prospective. single open-label sludy was conducted in 14 Canadian centres to assess lhe efncacy of I g, once a day intravenous ceftriaxone treatment administered for a minimum of three days in patients with lower respiratory tract infection. There were 137 patients enrolled. Age varied between 19 and 95 years (mean 68 years). Mosl patients (91 %) were diagnosed with community acquired pneumonia without bacteremia. Most of the cases (82%) were defined as modcralc or severe. Patients received ceftriaxone treatment for an average or five days. Macrolidcs or metronidazole were administered concomitantly wilh ceftriaxone in 34 patienls (25%). After a minimum of three days of ceftriaxone treatment. 59 palicnls (43%) were switched to oral antibiotics. Favourable treatment outcome was found in 92.9% and treatment failure (including relapse of infection) in 7.1 % o lpalicnls. Evaluable patients accounted for 91 % of patients enrolled in the study. Clinical cure and clinical improvement were achieved in 64.6 and 28.3% of the evaluable patients. respectively. Relapse of infection occurred in two patients (1.8%). and treatment failure was recorded in six cases (5.3%). Twelve patients (8.8%) died clue to reasons unrelated to the sludy treatment. Three adverse event (hives, diarrhea and phlebitis at the injection site) were possibly related to the study drug. A cross-Canada in vitro susceptibility surveillance study of bacterial pathogens. frequently the cause of pneumonia. found ceftriaxone to have minimal inhibitory concentrations in 90% of isolates that would support such a dosing regimen. with the exception of Enterobacter species. These rcsults support the use of 1 g, once daily ceftriaxone for the empirical treatment of pneumonia in those patients requiring hospitalization.

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Physicochemical and Antifungal Properties of Clotrimazole in Combination with High-Molecular Weight Chitosan as a Multifunctional Excipient

Marine Drugs ◽

10.3390/md18120591 ◽

2020 ◽

Vol 18 (12) ◽

pp. 591

Author(s):

Bożena Grimling ◽

Bożena Karolewicz ◽

Urszula Nawrot ◽

Katarzyna Włodarczyk ◽

Agata Górniak

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Weight Ratio ◽

Scanning Calorimetry ◽

Minimal Inhibitory Concentrations ◽

Dissolution Tests ◽

Effective Combination ◽

The Impact ◽

High Molecular Weight Chitosan

Chitosans represent a group of multifunctional drug excipients. Here, we aimed to estimate the impact of high-molecular weight chitosan on the physicochemical properties of clotrimazole–chitosan solid mixtures (CL–CH), prepared by grinding and kneading methods. We characterised these formulas by infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffractometry, and performed in vitro clotrimazole dissolution tests. Additionally, we examined the antifungal activity of clotrimazole–chitosan mixtures against clinical Candida isolates under neutral and acid conditions. The synergistic effect of clotrimazole and chitosan S combinations was observed in tests carried out at pH 4 on Candida glabrata strains. The inhibition of C. glabrata growth reached at least 90%, regardless of the drug/excipient weight ratio, and even at half of the minimal inhibitory concentrations of clotrimazole. Our results demonstrate that clotrimazole and high-molecular weight chitosan could be an effective combination in a topical antifungal formulation, as chitosan acts synergistically with clotrimazole against non-albicans candida strains.

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In Vitro Interaction between Isavuconazole and Tacrolimus, Cyclosporin A, or Sirolimus against Aspergillus Species

Journal of Fungi ◽

10.3390/jof6030103 ◽

2020 ◽

Vol 6 (3) ◽

pp. 103 ◽

Cited By ~ 3

Author(s):

Patrick Schwarz ◽

Eric Dannaoui

Keyword(s):

Cyclosporin A ◽

Aspergillus Terreus ◽

Susceptibility Testing ◽

Inhibitory Concentration ◽

Antifungal Susceptibility ◽

Reference Method ◽

Common Species ◽

Minimal Inhibitory Concentrations ◽

In Vitro Interaction

The interaction of isavuconazole with immunosuppressors (tacrolimus, cyclosporin A, or sirolimus) against 30 Aspergillus isolates belonging to the most common species responsible for invasive aspergillosis in humans (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) was evaluated in vitro by a microdilution checkerboard technique based on the EUCAST reference method for antifungal susceptibility testing. The interpretation of the results was performed based on the fractional inhibitory concentration index. The combination of isavuconazole with tacrolimus, cyclosporin A, or sirolimus, was synergistic for 56, 20, or 10% of the isolates, respectively. Interestingly synergy of the combination of isavuconazole with tacrolimus was also achieved for the majority of azole-resistant isolates of A. fumigatus, and for all A. niger isolates with isavuconazole minimal inhibitory concentrations ≥ 8 µg/mL. Antagonistic interactions were never observed for any combination tested.

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Once-daily gentamicin therapy for experimental Escherichia coli meningitis.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.1.49 ◽

1997 ◽

Vol 41 (1) ◽

pp. 49-53 ◽

Cited By ~ 23

Author(s):

A Ahmed ◽

M M París ◽

M Trujillo ◽

S M Hickey ◽

L Wubbel ◽

...

Keyword(s):

In Vivo Studies ◽

Bacterial Killing ◽

Once Daily ◽

E Coli ◽

Aminoglycoside Therapy ◽

Gentamicin Concentration ◽

Gentamicin Therapy ◽

The Impact

In vitro and in vivo studies have demonstrated that the bacteriologic efficacy of once-daily aminoglycoside therapy is equivalent to that achieved with conventional multiple daily dosing. The impact of once-daily dosing for meningitis has not been studied. Using the well-characterized rabbit meningitis model, we compared two regimens of the same daily dosage of gentamicin given either once or in three divided doses for 24 or 72 h. The initial 1 h mean cerebrospinal fluid (CSF) gentamicin concentration for animals receiving a single dose (2.9 +/- 1.7 micrograms/ml) was threefold higher than that for the animals receiving multiple doses. The rate of bacterial killing in the first 8 h of treatment was significantly greater for the animals with higher concentrations in their CSF (-0.21 +/- 0.19 versus -0.03 +/- 0.22 log10 CFU/ml/h), suggesting concentration-dependent killing. By 24h, the mean reduction in bacterial titers was similar for the two regimens. In animals treated for 72 h, no differences in bactericidal activity was noted for 24, 48, or 72 h. Gentamicin at two different dosages was administered intracisternally to a separate set of animals to achieve considerably higher CSF gentamicin concentrations. In these animals, the rate of bacterial clearance in the first 8 h (0.52 +/- 0.15 and 0.58 +/- 0.15 log10 CFU/ml/h for the lower and higher dosages, respectively) was significantly greater than that in animals treated intravenously. In conclusion, there is evidence of concentration-dependent killing with gentamicin early in treatment for experimental E. coli meningitis, and once-daily dosing therapy appears to be at least as effective as multiple-dose therapy in reducing bacterial counts in CSF.

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Optimizing pharmacokinetics/pharmacodynamics of β-lactam/β-lactamase inhibitor combinations against high inocula of ESBL-producing bacteria

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa412 ◽

2020 ◽

Vol 76 (1) ◽

pp. 179-183 ◽

Cited By ~ 1

Author(s):

Vincent H Tam ◽

Henrietta Abodakpi ◽

Weiqun Wang ◽

Kimberly R Ledesma ◽

Paul R Merlau ◽

...

Keyword(s):

Standard Dose ◽

Recursive Partitioning ◽

Hollow Fibre ◽

Infection Model ◽

Emax Model ◽

Inoculum Effect ◽

The Impact ◽

Lactamase Inhibitor

Abstract Objectives Reduced in vitro β-lactam activity against a dense bacterial population is well recognized. It is commonly attributed to the presence of β-lactamase(s) and it is unknown whether the inoculum effect could be diminished by a β-lactamase inhibitor. We evaluated different β-lactam/β-lactamase inhibitor combinations in suppressing a high inoculum of ESBL-producing bacteria. Methods Three clinical isolates expressing representative ESBLs (CTX-M-15 and SHV-12) were examined. The impact of escalating β-lactamase inhibitor (tazobactam or avibactam) concentrations on β-lactam (piperacillin or ceftazidime) MIC reduction was characterized by an inhibitory sigmoid Emax model. The effect of various dosing regimens of β-lactam/β-lactamase inhibitor combinations was predicted using %T>MICi and selected exposures were experimentally validated in a hollow-fibre infection model over 120 h. The threshold exposure to suppress bacterial regrowth was identified using recursive partitioning. Results A concentration-dependent reduction in β-lactam MIC was observed (r2 ≥0.93). Regrowth could be suppressed in all six experiments using %T>MICi ≥73.6%, but only one out of six experiments below the threshold (P = 0.015). The exposures to suppress regrowth might be attained using the clinical dose of avibactam, but a much higher dose than the standard dose would be needed for tazobactam. Conclusions A dense population of ESBL-producing bacteria could be suppressed by an optimized dosing regimen of selected β-lactam/β-lactamase inhibitor combinations. The reversibility of enzyme inhibition could play an important role in diminishing the inoculum effect. In vivo investigations to validate these findings are warranted.

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