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 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 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 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 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 against Mycobacterium abscessus in vitro

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.

scholarly journals Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study

2017 ◽  
Vol 10 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Grazielle Millo ◽  
Apa Juntavee ◽  
Ariya Ratanathongkam ◽  
Natsajee Nualkaew ◽  
Peerapattana, Jomjai ◽  
...  
Keyword(s):  
High Performance ◽  
In Vitro Study ◽  
Punica Granatum ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Inhibitory Effects ◽  
Cariogenic Bacteria ◽  
Zones Of Inhibition ◽  
Time Kill

ABSTRACT Aim This study evaluated the in vitro antibacterial effects of the formulated Punica granatum (PG) gel against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus casei. Materials and methods The PG extract was dissolved in water at 500 mg/mL. High performance liquid chromatography (HPLC) was used for identification and quantification of chemical marker punicalagin. Minimum bactericidal concentration (MBC) and time-kill assay (TKA) were investigated. Antibacterial activities of the formulated PG gel, 2% chlorhexidine (CHX) gel and blank gel were tested by measuring the zones of inhibition through agar well diffusion method. Results The HPLC results showed presence of punicalagin at 2023.58 ± 25.29 μg/mL in the aqueous PG extract and at 0.234% (w/w) in the formulated PG gel. The MBC for S. mutans, S. Sanguinis, and L. casei were 250, 125, and 500 mg/mL respectively. The TKA of 500 mg/mL aqueous PG extract showed total inhibition of S. mutans, S. Sanguinis, and L. casei at 6, 1, and 24 hours contact time respectively. Agar well diffusion revealed that for S. mutans, CHX gel > PG gel > blank gel; for S. sanguinis, CHX gel = PG gel > blank gel; for L. casei, CHX gel > PG gel = blank gel. Comparison of the PG gel potency showed that S. sanguinis = S. mutans > L. casei. Conclusion The PG gel equivalent to 0.234% punicalagin (w/w) inhibited S. mutans and S. sanguinis but not L. casei within 24 hours incubation period and has the potential to be used for caries prevention. How to cite this article Millo G, Juntavee A, Ratanathongkam A, Nualkaew N, Peerapattana J, Chatchiwiwattana S. Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):152-157.

Serratia marcescans Contamination of Antiseptic Soap Containing Triclosan: Implications for Nosocomial Infection

1984 ◽  
Vol 5 (9) ◽  
pp. 427-430 ◽  
Author(s):  
M. Anita Barry ◽  
Donald E. Craven ◽  
Theresa A. Goularte ◽  
Deborah A. Lichtenberg
Keyword(s):  
Intensive Care Unit ◽  
Pseudomonas Aeruginosa ◽  
Intensive Care ◽  
Nosocomial Infection ◽  
Surgical Intensive Care Unit ◽  
Minimal Bactericidal Concentration ◽  
Surgical Intensive Care ◽  
Time Kill ◽  
The Impact

Abstract During a recent investigation in our surgical intensive care unit, we found that several bottles of the antiseptic handwashing soap, OR Scrub®, were contaminated with Serratia marcescens. OR Scrub® contains 1% triclosan, lanolin, and detergents. The antimicrobial efficacy of OR Scrub® was examined in vitro using serial two-fold dilutions of soap inoculated with various concentrations of different nosocomial pathogens. The minimal bactericidal concentration (MBC) of OR Scrub® against Pseudomonas aeruginosa and several strains of S. marcescens was ≤1:2 By comparison, a non-antiseptic soap from the same manufacturer (Wash®) and 4% chlorhexidine (Hibiclens®) had MBCs for all strains tested of at least 1:64. Time-kill curves confirmed the findings of the initial experiments.This is the first report of extrinsic contamination of antiseptic soap containing triclosan. No infections could be attributed to the contaminated soap, but sporadic outbreaks of Serratia have occurred in the intensive care unit with no identifiable source. Although there have been few studies on the impact of antiseptic soap in reducing nosocomial infection, we question whether a soap with the limitations of OR Scrub® should be used in intensive care units or operating rooms.

scholarly journals Pharmacodynamic Analysis of the Activity of Quinupristin-Dalfopristin against Vancomycin-ResistantEnterococcus faecium with Differing MBCs via Time-Kill-Curve and Postantibiotic Effect Methods

1998 ◽  
Vol 42 (9) ◽  
pp. 2188-2192 ◽  
Author(s):  
Jeffrey R. Aeschlimann ◽  
Michael J. Rybak
Keyword(s):  
Antibacterial Activities ◽  
Water Soluble ◽  
Postantibiotic Effect ◽  
Curve Method ◽  
Highly Correlated ◽  
Kill Curve ◽  
The Individual ◽  
Time Kill

ABSTRACT Quinupristin-dalfopristin (Q-D) is a new water-soluble, semisynthetic antibiotic that is derived from natural streptogramins and that is combined in a 30:70 ratio. A number of studies have described the pharmacodynamic properties of this drug, but most have investigated only staphylococci or streptococci. We evaluated the relationship between Q-D, quinupristin (Q), and/or dalfopristin (D) susceptibility parameters and antibacterial activities against 22 clinical isolates of vancomycin-resistant Enterococcus faecium (VREF) by using the concentration-time-kill-curve method and by measuring postantibiotic effects. Q-D, Q, and D MICs and minimum bactericidal concentrations (MBCs) ranged from 0.125 to 1 and 0.25 to 64, 8 to 512 and >512, and 2 to 8 and 8 to 512 μg/ml, respectively. There were no significant relationships between susceptibilities to the individual components and the susceptibilities to the Q-D combination product. In the time-kill-curves studies, Q-D at a concentration of 6 μg/ml was at least bacteriostatic against all VREF tested. There was increased activity against more susceptible isolates when the isolates were grouped either by Q-D MBCs or by Q MICs. By multivariate regression analyses, the percent change in the inoculum from that at the baseline was significantly correlated with the Q MIC (R = 0.74; P = 0.008) and the Q-D concentration-to-MBC ratio (R = 0.58;P = 0.02) and was inversely correlated with the Q-D MBC-to-MIC ratio (R = 0.68; P = 0.003). A strong correlation existed between the killing rate and the Q-D concentration-to-MBC ratio (R = 0.99;P < 0.0001). Time to 99.9% killing was best correlated with the Q-D MBC (R = 0.96;P < 0.0001). The postantibiotic effect ranged from 0.2 to 3.2 h and was highly correlated with the Q-D concentration-to-MBC ratio (R = 0.96;P < 0.0001) and was less highly correlated with the Q MIC (R = 0.42; P = 0.04). Further study of these relationships with in vitro or in vivo infection models that simulate Q-D pharmacokinetics should further define the utility of these pharmacodynamic parameters in the prediction of Q-D activity for the treatment of VREF infections in humans.

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

2020 ◽  
Vol 76 (1) ◽  
pp. 179-183 ◽  
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&gt;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&gt;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.

scholarly journals Development and Qualification of a Pharmacodynamic Model for the Pronounced Inoculum Effect of Ceftazidime against Pseudomonas aeruginosa

2008 ◽  
Vol 53 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Jürgen B. Bulitta ◽  
Neang S. Ly ◽  
Jenny C. Yang ◽  
Alan Forrest ◽  
William J. Jusko ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Predictive Performance ◽  
Pkpd Model ◽  
Infection Models ◽  
The Mean ◽  
Inoculum Effect ◽  
Successful Replication ◽  
Time Kill ◽  
The Impact

ABSTRACT Evidence is mounting in support of the inoculum effect (i.e., slow killing at large initial inocula [CFUo]) for numerous antimicrobials against a variety of pathogens. Our objectives were to (i) determine the impact of the CFUo of Pseudomonas aeruginosa on ceftazidime activity and (ii) to develop and validate a pharmacokinetic/pharmacodynamic (PKPD) mathematical model accommodating a range of CFUo. Time-kill experiments using ceftazidime at seven concentrations up to 128 mg/liter (MIC, 2 mg/liter) were performed in duplicate against P. aeruginosa PAO1 at five CFUo from 105 to 109 CFU/ml. Samples were collected over 24 h and fit by candidate models in NONMEM VI and S-ADAPT 1.55 (all data were comodeled). External model qualification integrated data from eight previously published studies. Ceftazidime displayed approximately 3 to 4 log10 CFU/ml net killing at 106.2 CFUo and concentrations of 4 mg/liter (or higher), less than 1.6 log10 CFU/ml killing at 107.3 CFUo, and no killing at 108.0 CFUo for concentrations up to 128 mg/liter. The proposed mechanism-based model successfully described the inoculum effect and the concentration-independent lag time of killing. The mean generation time was 28.3 min. The effect of an autolysin was assumed to inhibit successful replication. Ceftazidime concentrations of 0.294 mg/liter stimulated the autolysin effect by 50%. The model was predictive in the internal cross-validation and had excellent in silico predictive performance for published studies of P. aeruginosa ATCC 27853 for various CFUo. The proposed PKPD model successfully described and predicted the pronounced inoculum effect of ceftazidime in vitro and integrated data from eight literature studies to support translation from time-kill experiments to in vitro infection models.

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