scholarly journals Pharmacokinetics/Pharmacodynamics of Peptide Deformylase Inhibitor GSK1322322 against Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus in Rodent Models of Infection

2015 ◽  
Vol 60 (1) ◽  
pp. 180-189 ◽  
Author(s):  
Jennifer Hoover ◽  
Thomas Lewandowski ◽  
Robert J. Straub ◽  
Steven J. Novick ◽  
Peter DeMarsh ◽  
...  

ABSTRACTGSK1322322 is a novel inhibitor of peptide deformylase (PDF) with goodin vitroactivity against bacteria associated with community-acquired pneumonia and skin infections. We have characterized thein vivopharmacodynamics (PD) of GSK1322322 in immunocompetent animal models of infection withStreptococcus pneumoniaeandHaemophilus influenzae(mouse lung model) and withStaphylococcus aureus(rat abscess model) and determined the pharmacokinetic (PK)/PD index that best correlates with efficacy and its magnitude. Oral PK studies with both models showed slightly higher-than-dose-proportional exposure, with 3-fold increases in area under the concentration-time curve (AUC) with doubling doses. GSK1322322 exhibited dose-dependentin vivoefficacy against multiple isolates ofS. pneumoniae,H. influenzae, andS. aureus. Dose fractionation studies with twoS. pneumoniaeandS. aureusisolates showed that therapeutic outcome correlated best with the free AUC/MIC (fAUC/MIC) index inS. pneumoniae(R2, 0.83), whereasfAUC/MIC and free maximum drug concentration (fCmax)/MIC were the best efficacy predictors forS. aureus(R2, 0.9 and 0.91, respectively). Median dailyfAUC/MIC values required for stasis and for a 1-log10reduction in bacterial burden were 8.1 and 14.4 for 11S. pneumoniaeisolates (R2, 0.62) and 7.2 and 13.0 for fiveH. influenzaeisolates (R2, 0.93). The data showed that for eightS. aureusisolates,fAUC correlated better with efficacy thanfAUC/MIC (R2, 0.91 and 0.76, respectively), as efficacious AUCs were similar for all isolates, independent of their GSK1322322 MIC (range, 0.5 to 4 μg/ml). MedianfAUCs of 2.1 and 6.3 μg · h/ml were associated with stasis and 1-log10reductions, respectively, forS. aureus.

2020 ◽  
Vol 64 (11) ◽  
Author(s):  
Alexander J. Lepak ◽  
Wen Wang ◽  
David R. Andes

ABSTRACT MRX-8 is a novel polymyxin analogue in development for the treatment of infections caused by Gram-negative pathogens, including those resistant to other antibiotic classes. In the present study, we examined the pharmacodynamic activity of MRX-8 against a variety of common Gram-negative pathogens in the neutropenic mouse thigh and lung models. Additionally, we examined polymyxin B (PMB) as a comparator. Plasma pharmacokinetics of MRX-8 and PMB were linear over a broad dosing range of 0.156 to 10 mg/kg of body weight and had similar AUC0–∞ (area under the drug concentration-time curve from 0 h to infinity) exposures of MRX-8, 0.22 to 12.64 mg · h/liter, and PMB, 0.12 to 13.22 mg · h/liter. Dose fractionation was performed for MRX-8 using a single Escherichia coli isolate, and the results demonstrated that both Cmax (maximum concentration of drug in serum)/MIC and AUC/MIC ratios were strongly associated with efficacy. In the thigh model, dose-ranging studies included strains of E. coli (n = 3), Pseudomonas aeruginosa (n = 2), Klebsiella pneumoniae (n = 3), and Acinetobacter baumannii (n = 1). Both MRX-8 and PMB exhibited increased effects with increasing doses. MRX-8 and PMB free AUC/MIC exposures for net stasis were similar for E. coli and K. pneumoniae at 20 to 30. Notably, for P. aeruginosa and A. baumannii, the free AUC/MIC ratio for stasis was numerically much smaller for MRX-8 at 6 to 8 than for PMB at 16 to 37. In the lung model, MRX-8 was also more effective than PMB when dosed to achieve similar free-drug AUC exposures over the study period. MRX-8 is a promising novel polymyxin analogue with in vivo activity against many different clinically relevant species in both the mouse thigh and lung models.


2011 ◽  
Vol 55 (7) ◽  
pp. 3453-3460 ◽  
Author(s):  
Arnold Louie ◽  
Weiguo Liu ◽  
Robert Kulawy ◽  
G. L. Drusano

ABSTRACTTorezolid phosphate (TR-701) is the phosphate monoester prodrug of the oxazolidinone TR-700 which demonstrates potentin vitroactivity against Gram-positive bacteria, including methicillin-susceptibleStaphylococcus aureus(MSSA) and methicillin-resistantS. aureus(MRSA). The pharmacodynamics of TR-701 or TR-700 (TR-701/700) againstS. aureusis incompletely defined. Single-dose pharmacokinetic studies were conducted in mice for TR-701/700. Forty-eight-hour dose range and 24-hour dose fractionation studies were conducted in a neutropenic mouse thigh model ofS. aureusinfection using MRSA ATCC 33591 to identify the dose and schedule of administration of TR-701/700 that was linked with optimized antimicrobial effect. Additional dose range studies compared the efficacies of TR-701/700 and linezolid for one MSSA strain and one community-associated MRSA strain. In dose range studies, TR-701/700 was equally bactericidal against MSSA and MRSA. Mean doses of 37.6 and 66.9 mg/kg of body weight/day of TR-701/700 resulted in stasis and 1 log CFU/g decreases in bacterial densities, respectively, at 24 h, and mean doses of 35.3, 46.6, and 71.1 mg/kg/day resulted in stasis and 1 and 2 log CFU/g reductions, respectively, at 48 h. Linezolid administered at doses as high as 150 mg/kg/day did not achieve stasis at either time point. Dose fractionation studies demonstrated that the area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC ratio) was the pharmacodynamic index for TR-701/700 that was linked with efficacy. TR-701/700 was highly active against MSSA and MRSA,in vivo, and was substantially more efficacious than linezolid, although linezolid's top exposure has half the human exposure. Dose fractionation studies showed that AUC/MIC was the pharmacodynamic index linked with efficacy, indicating that once-daily dosing in humans is feasible.


2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Yu-Feng Zhou ◽  
Ping Liu ◽  
Shu-He Dai ◽  
Jian Sun ◽  
Ya-Hong Liu ◽  
...  

ABSTRACT We determined in vivo efficacy and target PK/PD exposures of antofloxacin against Streptococcus pneumoniae and Staphylococcus aureus in the murine pneumonia model. The mean plasma free drug area under the concentration-time curve/MIC (fAUC/MIC) targets associated with stasis and 1-log10 and 2-log10 kill effects were 8.93, 19.2, and 48.1, respectively, for S. pneumoniae, whereas they were 30.5, 55.4, and 115.8, respectively, for S. aureus. The fAUC/MIC targets in murine lung epithelial lining fluids (ELF) for the same endpoints were nearly 2-fold higher than those in plasma.


2015 ◽  
Vol 59 (8) ◽  
pp. 4644-4652 ◽  
Author(s):  
Sharon Min ◽  
Karen Ingraham ◽  
Jianzhong Huang ◽  
Lynn McCloskey ◽  
Sarah Rilling ◽  
...  

ABSTRACTThe continuous emergence of multidrug-resistant pathogenic bacteria is compromising the successful treatment of serious microbial infections. GSK1322322, a novel peptide deformylase (PDF) inhibitor, shows goodin vitroantibacterial activity and has demonstrated safety and efficacy in human proof-of-concept clinical studies.In vitrostudies were performed to determine the frequency of resistance (FoR) to this antimicrobial agent in major pathogens that cause respiratory tract and skin infections. Resistance to GSK1322322 occurred at high frequency through loss-of-function mutations in the formyl-methionyl transferase (FMT) protein inStaphylococcus aureus(4/4 strains) andStreptococcus pyogenes(4/4 strains) and via missense mutations inStreptococcus pneumoniae(6/21 strains), but the mutations were associated with severein vitroand/orin vivofitness costs. The overall FoR to GSK1322322 was very low inHaemophilus influenzae, with only one PDF mutant being identified in one of four strains. No target-based mutants were identified fromS. pyogenes, and only one or no PDF mutants were isolated in three of the fourS. aureusstrains studied. InS. pneumoniae, PDF mutants were isolated from only six of 21 strains tested; an additional 10 strains did not yield colonies on GSK1322322-containing plates. Most of the PDF mutants characterized from those three organisms (35/37 mutants) carried mutations in residues at or in close proximity to one of three highly conserved motifs that are part of the active site of the PDF protein, with 30 of the 35 mutations occurring at position V71 (using theS. pneumoniaenumbering system).


2008 ◽  
Vol 52 (10) ◽  
pp. 3492-3496 ◽  
Author(s):  
W. A. Craig ◽  
D. R. Andes

ABSTRACT Ceftobiprole medocaril is the parenteral prodrug of ceftobiprole, a novel pyrrolidinone broad-spectrum cephalosporin with in vitro and in vivo bactericidal activities against methicillin-resistant Staphylococcus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae (PRSP). We have used murine thigh and lung infection models in neutropenic and normal mice to characterize the in vivo pharmacokinetic (PK)-pharmacodynamic (PD) activities of ceftobiprole against multiple strains of S. aureus (including MRSA), S. pneumoniae (including PRSP), and gram-negative bacilli. Serum levels of ceftobiprole following the administration of multiple doses were determined by a microbiological assay. In vivo bactericidal activities and postantibiotic effects (PAEs) of ceftobiprole against MRSA and PRSP strains were determined from serial CFU/thigh values following single doses of ceftobiprole (40 and 160 mg/kg of body weight). Dose fractionation studies were used to determine which PK-PD index correlated best with activity. Magnitudes of the PK-PD indices were calculated from MICs and PK parameters. A sigmoid dose-response model was used to estimate the dose (mg/kg/24 h) required to achieve a static and 2-log10 kill effects over 24 h. PK results showed area under the concentration-time curve/dose values of 1.8 to 2.8 and half-lives of 0.29 to 0.51 h. MICs ranged from 0.015 to 2 μg/ml. Ceftobiprole demonstrated time-dependent killing; its in vivo PAEs varied from 3.8 h to 4.8 h for MRSA and from 0 to 0.8 h for PRSP. The time above MIC (T > MIC) correlated best with efficacy for both MRSA and PRSP. The T > MIC values required for the static doses were significantly longer (P < 0.001) for Enterobacteriaceae (36 to 45%) than for S. aureus (14 to 28%) and S. pneumoniae (15 to 22%). The drug showed activities in the lung model similar to those in the thigh model. The presence of neutrophils significantly enhanced the activity of ceftobiprole against S. pneumoniae but only slightly against Klebsiella pneumoniae. Based on its PD profile, ceftobiprole is a promising new β-lactam agent with activity against gram-negative and gram-positive organisms including MRSA and PRSP.


2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Vien T. M. Le ◽  
Hoan N. Le ◽  
Marcos Gabriel Pinheiro ◽  
Kenneth J. Hahn ◽  
Mary L. Dinh ◽  
...  

ABSTRACT The protective efficacy of tedizolid phosphate, a novel oxazolidinone that potently inhibits bacterial protein synthesis, was compared to those of linezolid, vancomycin, and saline in a rabbit model of Staphylococcus aureus necrotizing pneumonia. Tedizolid phosphate was administered to rabbits at 6 mg/kg of body weight intravenously twice daily, which yielded values of the 24-h area under the concentration-time curve approximating those found in humans. The overall survival rate was 83% for rabbits treated with 6 mg/kg tedizolid phosphate twice daily and 83% for those treated with 50 mg/kg linezolid thrice daily (P = 0.66 by the log-rank test versus the results obtained with tedizolid phosphate). These survival rates were significantly greater than the survival rates of 17% for rabbits treated with 30 mg/kg vancomycin twice daily (P = 0.003) and 17% for rabbits treated with saline (P = 0.002). The bacterial count in the lungs of rabbits treated with tedizolid phosphate was significantly decreased compared to that in the lungs of rabbits treated with saline, although it was not significantly different from that in the lungs of rabbits treated with vancomycin or linezolid. The in vivo bacterial production of alpha-toxin and Panton-Valentine leukocidin, two key S. aureus-secreted toxins that play critical roles in the pathogenesis of necrotizing pneumonia, in the lungs of rabbits treated with tedizolid phosphate and linezolid was significantly inhibited compared to that in the lungs of rabbits treated with vancomycin or saline. Taken together, these results indicate that tedizolid phosphate is superior to vancomycin for the treatment of S. aureus necrotizing pneumonia because it inhibits the bacterial production of lung-damaging toxins at the site of infection.


2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Miao Zhao ◽  
Alexander J. Lepak ◽  
Karen Marchillo ◽  
Jamie VanHecker ◽  
David R. Andes

ABSTRACT NOSO-502 is a novel odilorhabdin antibiotic with potent activity against Enterobacteriaceae. The goal of these studies was to determine which pharmacokinetic/pharmacodynamic (PK/PD) indices and magnitude best correlated with efficacy in the murine thigh infection model. Six Escherichia coli and 6 Klebsiella pneumoniae isolates were utilized. MICs were determined using CLSI methods and ranged from 1 to 4 mg/liter. A neutropenic murine thigh infection model was utilized for all treatment studies. Single-dose plasma pharmacokinetics were determined in mice after subcutaneous administration of 7.81, 31.25, 125, and 500 mg/kg of body weight. Pharmacokinetic studies exhibited peak concentration (Cmax) values of 1.49 to 84.6 mg/liter, area under the concentration-time curve from 0 h to infinity (AUC0–∞) values of 1.94 to 352 mg · h/liter, and beta elimination half-lives of 0.41 to 1.1 h. Dose fractionation studies were performed using total drug doses of 7.81 mg/kg to 2,000 mg/kg fractionated into regimens of every 3 h (q3h), q6h, q12h, or q24h. Nonlinear regression analysis demonstrated that AUC/MIC was the PK/PD parameter that best correlated with efficacy (R2, 0.86). In subsequent studies, we used the neutropenic murine thigh infection model to determine the magnitude of NOSO-502 AUC/MIC needed for the efficacy against a diverse group of Enterobacteriaceae. Mice were treated with 4-fold-increasing doses (range, 3.91 to 1,000 mg/kg) of NOSO-502 every 6 h. The mean 24-h free-drug AUC/MIC (fAUC)/MIC) magnitudes associated with net stasis and 1-log kill endpoint for K. pneumoniae were 4.22 and 17.7, respectively. The mean fAUC/MIC magnitude associated with net stasis endpoint for E. coli was 10.4. NOSO-502 represents a promising novel, first-in-class odilorhabdin antibiotic with in vivo potency against Enterobacteriaceae.


2011 ◽  
Vol 55 (11) ◽  
pp. 5325-5330 ◽  
Author(s):  
Yan Q. Xiong ◽  
Wessam Abdel Hady ◽  
Antoine Deslandes ◽  
Astrid Rey ◽  
Laurent Fraisse ◽  
...  

ABSTRACTCationic antimicrobial peptides (CAPs) play important roles in host immune defenses. Plectasin is a defensin-like CAP isolated from the saprophytic fungusPseudoplectania nigrella. NZ2114 is a novel variant of plectasin with potent activity against Gram-positive bacteria. In this study, we investigated (i) thein vivopharmacokinetic and pharmacodynamic (PK/PD) characteristics of NZ2114 and (ii) thein vivoefficacy of NZ2114 in comparison with those of two conventional antibiotics, vancomycin or daptomycin, in an experimental rabbit infective endocarditis (IE) model due to a methicillin-resistantStaphylococcus aureus(MRSA) strain (ATCC 33591). All NZ2114 regimens (5, 10, and 20 mg/kg of body weight, intravenously [i.v.], twice daily for 3 days) significantly decreased MRSA densities in cardiac vegetations, kidneys, and spleen versus those in untreated controls, except in one scenario (5 mg/kg, splenic MRSA counts). The efficacy of NZ2114 was clearly dose dependent in all target tissues. At 20 mg/kg, NZ2114 showed a significantly greater efficacy than vancomycin (P< 0.001) and an efficacy similar to that of daptomycin. Of importance, only NZ2114 (in 10- and 20-mg/kg regimens) prevented posttherapy relapse in cardiac vegetations, kidneys, and spleen, while bacterial counts in these target tissues continued to increase in vancomycin- and daptomycin-treated animals. Thesein vivoefficacies were equivalent and significantly correlated with three PK indices investigated:fCmax/MIC (the maximum concentration of the free, unbound fraction of a drug in serum divided by the MIC),fAUC/MIC (where AUC is the area under the concentration-time curve), andf%T>MIC(%T>MICis the cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions), as analyzed by a sigmoid maximum-effect (Emax) model (R2> 0.69). The superior efficacy of NZ2114 in this MRSA IE model suggests the potential for further development of this compound for treating serious MRSA infections.


2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Alexander J. Lepak ◽  
Miao Zhao ◽  
Karen Marchillo ◽  
Jamie VanHecker ◽  
David R. Andes

ABSTRACT Omadacycline is an effective therapy for community-acquired bacterial pneumonia (CABP). Given its potent activity against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA), we sought to determine the pharmacodynamic activity and target pharmacokinetic/pharmacodynamic (PK/PD) exposures associated with a therapeutic effect in the neutropenic mouse pneumonia model against 10 MSSA/MRSA strains. The area under the concentration-time curve (AUC)/MIC associated with 1-log kill was noted at 24-h epithelial lining fluid (ELF) and plasma AUC/MIC exposures of ∼2 (ELF range, <0.93 to 19; plasma range, <1.06 to 17) and 2-log kill was noted at 24-h ELF and plasma AUC/MIC exposures of ∼12 (ELF range, 2.5 to 130; plasma range, 3.5 to 151).


2011 ◽  
Vol 79 (8) ◽  
pp. 3366-3376 ◽  
Author(s):  
Charles V. Rosadini ◽  
Jeffrey D. Gawronski ◽  
Daniel Raimunda ◽  
José M. Argüello ◽  
Brian J. Akerley

ABSTRACTNontypeableHaemophilus influenzae(NTHI) is a Gram-negative bacterial pathogen that causes upper and lower respiratory infections. Factors required for pulmonary infection by NTHI are not well understood. Previously, using high-throughput insertion tracking by deep sequencing (HITS), putative lung colonization factors were identified. Also, previous research indicates that secreted disulfide-dependent factors are important for virulence ofH. influenzae. In the present study, HITS data were compared with an informatics-based list of putative substrates of the periplasmic oxidoreductase DsbA to find and characterize secreted virulence factors. This analysis resulted in identification of the “zinc bindingessential forvirulence” (zev) locus consisting ofzevA(HI1249) andzevB(HI1248). NTHI mutants ofzevAandzevBgrew normally in rich medium but were defective for colonization in a mouse lung model. Mutants also exhibited severe growth defects in medium containing EDTA and were rescued by supplementation with zinc. Additionally, purified recombinant ZevA was found to bind to zinc with high affinity. Together, these data demonstrate thatzevABis a novel virulence factor important for zinc utilization ofH. influenzaeunder conditions where zinc is limiting. Furthermore, evidence presented here suggests that zinc limitation is likely an important mechanism for host defense against pathogens during lung infection.


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