scholarly journals Pharmacodynamic Profile of GSK2140944 against Methicillin-Resistant Staphylococcus aureus in a Murine Lung Infection Model

2015 ◽  
Vol 59 (8) ◽  
pp. 4956-4961 ◽  
Author(s):  
Wonhee So ◽  
Jared L. Crandon ◽  
David P. Nicolau
Keyword(s):  
Staphylococcus Aureus ◽  
Lung Infection ◽  
Infection Model ◽  
Respiratory Pathogens ◽  
Time Curve ◽  
Unbound Fraction ◽  
Methicillin Resistant ◽  
Murine Lung ◽  
Pharmacodynamic Profile

ABSTRACTGSK2140944 is a novel bacterial type II topoisomerase inhibitor within vitroactivity against key causative respiratory pathogens, including methicillin-resistantStaphylococcus aureus(MRSA). We described the pharmacodynamics of GSK2140944 against MRSA in the neutropenic murine lung infection model. MICs of GSK2140944 were determined by broth microdilution. Plasma and epithelial lining fluid (ELF) pharmacokinetics were evaluated to allow determination of pulmonary distribution. Six MRSA isolates were tested. GSK2140944 doses of 1.56 to 400 mg/kg of body weight every 6 h (q6h) were utilized. Efficacy as the change in log10CFU at 24 h compared with 0 h controls and the area under the concentration-time curve for the free, unbound fraction of a drug (fAUC)/MIC required for various efficacy endpoints were determined. GSK2140944 MICs were 0.125 to 0.5 mg/liter against the six MRSA isolates. ELF penetration ratios ranged from 1.1 to 1.4. Observed maximal decreases were 1.1 to 3.1 log10CFU in neutropenic mice. The meanfAUC/MIC ratios required for stasis and 1-log-unit decreases were 59.3 ± 34.6 and 148.4 ± 83.3, respectively. GSK2140944 displayedin vitroandin vivoactivity against MRSA. The pharmacodynamic profile of GSK2140944, as determined, supports its further development as a potential treatment option for pulmonary infections, including those caused by MRSA.

scholarly journals Comparative Efficacies of Human Simulated Exposures of Telavancin and Vancomycin against Methicillin-Resistant Staphylococcus aureus with a Range of Vancomycin MICs in a Murine Pneumonia Model

2010 ◽  
Vol 54 (12) ◽  
pp. 5115-5119 ◽  
Author(s):  
Jared L. Crandon ◽  
Joseph L. Kuti ◽  
David P. Nicolau
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Load ◽  
Infection Model ◽  
Time Curve ◽  
Unbound Fraction ◽  
Methicillin Resistant ◽  
Vancomycin Mics ◽  
Mrsa Strains

ABSTRACT Telavancin displays potent in vitro and in vivo activity against methicillin-resistant Staphylococcus aureus (MRSA), including strains with reduced susceptibility to vancomycin. We compared the efficacies of telavancin and vancomycin against MRSA strains with vancomycin MICs of ≥1 μg/ml in a neutropenic murine lung infection model. Thirteen clinical MRSA isolates (7 vancomycin-susceptible, 2 vancomycin-heteroresistant [hVISA], and 4 vancomycin-intermediate [VISA] isolates) were tested after 24 h, and 7 isolates (1 hVISA and 4 VISA isolates) were tested after 48 h of exposure. Mice were administered subcutaneous doses of telavancin at 40 mg/kg of body weight every 12 h (q12h) or of vancomycin at 110 mg/kg q12h; doses were designed to simulate the area under the concentration-time curve for the free, unbound fraction of drug (fAUC) observed for humans given telavancin at 10 mg/kg q24h or vancomycin at 1 g q12h. Efficacy was expressed as the 24- or 48-h change in lung bacterial density from pretreatment counts. At dose initiation, the mean bacterial load was 6.16 ± 0.26 log10 CFU/ml, which increased by averages of 1.26 ± 0.55 and 1.74 ± 0.68 log in untreated mice after 24 and 48 h, respectively. At both time points, similar CFU reductions were noted for telavancin and vancomycin against MRSA, with vancomycin MICs of ≤2 μg/ml. Both drugs were similarly efficacious after 24 and 48 h of treatment against the hVISA strains tested. Against VISA isolates, telavancin reduced bacterial burdens significantly more than vancomycin for 1 of 4 isolates after 24 h and for 3 of 4 isolates after 48 h. These data support the potential utility of telavancin for the treatment of MRSA pneumonia caused by pathogens with reduced susceptibility to vancomycin.

scholarly journals In Vivo Pharmacokinetic/Pharmacodynamic Targets of Levonadifloxacin against Staphylococcus aureus in a Neutropenic Murine Lung Infection Model

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Sachin S. Bhagwat ◽  
Hariharan Periasamy ◽  
Swapna S. Takalkar ◽  
Rajesh Chavan ◽  
Pavan Tayde ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Lung Infection ◽  
Infection Model ◽  
Phase 3 ◽  
Time Curve ◽  
Unbound Fraction ◽  
Content Type ◽  
Murine Lung ◽  
Selection Of

ABSTRACT Levonadifloxacin is a novel benzoquinolizine subclass of fluoroquinolone, active against quinolone-resistant Staphylococcus aureus. A phase 3 trial for levonadifloxacin and its oral prodrug was recently completed. The present study identified area under the concentration-time curve for the free, unbound fraction of a drug divided by the MIC (fAUC/MIC) as an efficacy determinant for levonadifloxacin in a neutropenic murine lung infection model. Mean plasma fAUC/MIC requirement for static and 1 log10 kill effects against 9 S. aureus were 8.1 ± 6.0 and 25.8 ± 12.3, respectively. These targets were employed in the selection of phase 3 doses.

Pharmacodynamics of RP 59500 (quinupristin-dalfopristin) administered by intermittent versus continuous infusion against Staphylococcus aureus-infected fibrin-platelet clots in an in vitro infection model.

1997 ◽  
Vol 41 (6) ◽  
pp. 1359-1363 ◽  
Author(s):  
M J Rybak ◽  
H H Houlihan ◽  
R C Mercier ◽  
G W Kaatz
Keyword(s):  
Staphylococcus Aureus ◽  
Continuous Infusion ◽  
Bactericidal Activity ◽  
Growth Control ◽  
Intermittent Infusion ◽  
Bacterial Density ◽  
Infection Model ◽  
Time Curve ◽  
Methicillin Resistant

We evaluated the bactericidal activity of RP 59500 (quinupristin-dalfopristin) against fibrin-platelet clots (FPC) infected with two clinical isolates of Staphylococcus aureus, one constitutively erythromycin and methicillin resistant (S. aureus AW7) and one erythromycin and methicillin susceptible (S. aureus 1199), in an in vitro pharmacodynamic infection model. RP 59500 was administered by continuous infusion (peak steady-state concentration of 6 microg/ml) or intermittent infusion (simulated regimens of 7.5 mg/kg of body weight every 6 h (q6h) q8h, and q12h. FPCs were infected with S. aureus to achieve an initial bacterial density of 10(9) CFU/g. Model experiments were run in duplicate over 72 h. Two FPCs were removed from each model at 0, 12, 24, 36, 48, and 72 h, and the bacterial densities (in CFU per gram) were determined and compared to those of growth control experiments. Additional samples were also removed from the model over the 72-h period for pharmacokinetic evaluation. All regimens significantly (P < or = 0.01) decreased bacterial densities in the infected FPCs for both isolates compared to growth controls. This occurred even though MBCs were equal to or greater than the RP 59500 concentrations achieved in the models. There were no significant differences found between the dosing frequencies and levels of killing when examining each isolate separately. However, examination of the residual bacterial densities (CFU per gram at 72 h) and visual inspection of the overall killing effect (killing curve plots over 72 h) clearly demonstrated a more favorable bactericidal activity against 1199 than against the AW7 isolate. This was most apparent when the q8h and the q12h AW7 regimens were compared to all 1199 treatment regimens by measuring the 72-h bacterial densities (P < or = 0.01). Killing (99.9%) was not achieved against the AW7 isolate. However, a 99.9% kill was demonstrated for all dosing regimens against the 1199 isolate. The area under the concentration-time curve from 0 to 24 h was found to be significantly correlated with reduction in bacterial density for the AW7 isolate (r = 0.74, P = 0.04). No resistance was detected during any experiment for either isolate. RP 59500 efficacy against constitutively erythromycin- and methicillin-resistant S. aureus may be improved by increasing organism exposure to RP 59500 as a function of dosing frequency.

scholarly journals Despite Antagonism in vitro, Pseudomonas aeruginosa Enhances Staphylococcus aureus Colonization in a Murine Lung Infection Model

2019 ◽  
Vol 10 ◽  
Author(s):  
Guillaume Millette ◽  
Jean-Philippe Langlois ◽  
Eric Brouillette ◽  
Eric H. Frost ◽  
André M. Cantin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Lung Infection ◽  
Infection Model ◽  
Murine Lung

scholarly journals In VivoPharmacodynamics of Torezolid Phosphate (TR-701), a New Oxazolidinone Antibiotic, against Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Strains in a Mouse Thigh Infection Model

2011 ◽  
Vol 55 (7) ◽  
pp. 3453-3460 ◽  
Author(s):  
Arnold Louie ◽  
Weiguo Liu ◽  
Robert Kulawy ◽  
G. L. Drusano
Keyword(s):  
Staphylococcus Aureus ◽  
Dose Range ◽  
Dose Fractionation ◽  
Infection Model ◽  
Pharmacokinetic Studies ◽  
Time Curve ◽  
Methicillin Resistant ◽  
Content Type

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.

scholarly journals Activities of Clindamycin, Daptomycin, Doxycycline, Linezolid, Trimethoprim-Sulfamethoxazole, and Vancomycin against Community-Associated Methicillin-Resistant Staphylococcus aureus with Inducible Clindamycin Resistance in Murine Thigh Infection and In Vitro Pharmacodynamic Models

2008 ◽  
Vol 52 (6) ◽  
pp. 2156-2162 ◽  
Author(s):  
Kerry L. LaPlante ◽  
Steven N. Leonard ◽  
David R. Andes ◽  
William A. Craig ◽  
Michael J. Rybak
Keyword(s):  
Staphylococcus Aureus ◽  
Inoculum Size ◽  
In Vivo Model ◽  
Infection Model ◽  
Time Curve ◽  
In Vivo Models ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance

ABSTRACT Controversy exists about the most effective treatment options for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and about the ability of these strains to develop inducible resistance to clindamycin during therapy. Using both in vitro pharmacodynamic and murine thigh infection models, we evaluated and compared several antimicrobial compounds against CA-MRSA. Strains with inducible macrolide lincosamide-streptogramin type B (iMLSB) resistance and strains in which resistance was noninducible were evaluated. Two levels of inocula (105 and 107) were evaluated for clindamycin activity in the in vivo model. In both models, the antimicrobial evaluation was performed in triplicate, and bacterial quantification occurred over 72 h, with drug doses that were designed to simulate the free drug area-under-the-concentration-time curve values (fAUCs) obtained from human samples. When the activity of clindamycin against the iMLSB strains was evaluated, constitutive resistance was noted at 24 h (MIC of >256), and failure was noted at an inoculum of ≥106 in the in vivo models. However, at a low inoculum (105) in the murine thigh-infection model, clindamycin demonstrated modest activity, reducing the CFU/thigh count for clindamycin resistance-inducible strains at 72 h (0.45 to 1.3 logs). Overall, administration of daptomycin followed by vancomycin demonstrated the most significant kill against all strains in both models. Against the clindamycin noninducible strain, clindamycin and doxycycline demonstrated significant kill. Doxycycline, linezolid, and trimethoprim-sulfamethoxazide (not run in the murine model) demonstrated bacteriostatic activity against clindamycin resistance-inducible isolates. This study demonstrates that clindamycin's activity against the iMLSB strains tested is partially impacted by inoculum size. At present, there are several alternatives that appear promising for treating clindamycin resistance-inducible strains of CA-MRSA.

scholarly journals Evaluation of Once-Daily Vancomycin against Methicillin-Resistant Staphylococcus aureus in a Hollow-Fiber Infection Model

2011 ◽  
Vol 56 (2) ◽  
pp. 682-686 ◽  
Author(s):  
Anthony M. Nicasio ◽  
Jürgen B. Bulitta ◽  
Thomas P. Lodise ◽  
Rebecca E. D'Hondt ◽  
Robert Kulawy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Hollow Fiber ◽  
Daily Administration ◽  
Dose Fractionation ◽  
Infection Model ◽  
Time Curve ◽  
Once Daily ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTFor methicillin-resistantStaphylococcus aureus(MRSA) infections, data suggest that the clinical response is significantly better if the total vancomycin area under the concentration-time curve (AUC)/MIC ratio is ≥400. While the AUC/MIC ratio is the accepted pharmacokinetic/pharmacodynamic (PK/PD) index for vancomycin, this target has been achieved using multiple daily doses. We are unaware of a systematically designed dose fractionation study to compare the bactericidal activity of once-daily administration to that of traditional twice-daily administration. A dose fractionation study was performed with vancomycin in anin vitrohollow-fiber infection model against an MRSA USA300 strain (MIC of 0.75 μg/ml) using an inoculum of ∼106CFU/ml. The three vancomycin regimens evaluated for 168 h were 2 g every 24 h (q24h) as a 1-h infusion, 1 g q12h as a 1-h infusion, and 2 g q24h as a continuous infusion. Free steady-state concentrations (assuming 45% binding) for a total daily AUC/MIC ratio of ≥400 were simulated for all regimens. A validated liquid chromatography-tandem mass spectrometry method was used to determine vancomycin concentrations. Although once-daily and twice-daily dosage regimens exhibited total trough concentrations of <15 μg/ml, all regimens achieved similar bactericidal activities between 24 and 168 h and suppressed the amplification of nonsusceptible subpopulations. No colonies were found on agar plates with 3× MIC for any of the treatment arms. Overall, the results suggest that once-daily vancomycin administration is feasible from a PK/PD perspective and merits further inquiry in the clinical arena.

scholarly journals Evaluation of Accessory Gene Regulator (agr) Group and Function in the Proclivity towards Vancomycin Intermediate Resistance in Staphylococcus aureus

2006 ◽  
Vol 51 (3) ◽  
pp. 1089-1091 ◽  
Author(s):  
Brian T. Tsuji ◽  
Michael J. Rybak ◽  
Kerry L. Lau ◽  
George Sakoulas
Keyword(s):  
Staphylococcus Aureus ◽  
Wild Type ◽  
Accessory Gene ◽  
Time Curve ◽  
Unbound Fraction ◽  
Accessory Gene Regulator ◽  
Intermediate Resistance ◽  
And Function ◽  
Type Strains

ABSTRACT Simulated therapeutic vancomycin exposures were evaluated against agr wild-type and knockout Staphylococcus aureus groups I, II, III, and IV using an in vitro pharmacodynamic model. All agr groups developed intermediate resistance to vancomycin after subtherapeutic exposure. The free unbound fraction of the area under the concentration-time curve (fAUC/MIC) required to suppress resistance was fourfold higher (P < 0.001) in agr dysfunctional strains (112 to 169) than that in parent wild-type strains (28).

scholarly journals Sanguiin H-6 Fractionated from Cloudberry (Rubus chamaemorus) Seeds Can Prevent the Methicillin-Resistant Staphylococcus aureus Biofilm Development during Wound Infection

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1481
Author(s):  
John Jairo Aguilera-Correa ◽  
Sara Fernández-López ◽  
Iskra Dennisse Cuñas-Figueroa ◽  
Sandra Pérez-Rial ◽  
Hanna-Leena Alakomi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Infection ◽  
Preventive Measure ◽  
Surgical Site Infections ◽  
Infection Model ◽  
Growth Media ◽  
Methicillin Resistant ◽  
Biofilm Development

Staphylococcus aureus is the most common cause of surgical site infections and its treatment is challenging due to the emergence of multi-drug resistant strains such as methicillin-resistant S. aureus (MRSA). Natural berry-derived compounds have shown antimicrobial potential, e.g., ellagitannins such as sanguiin H-6 and lambertianin C, the main phenolic compounds in Rubus seeds, have shown antimicrobial activity. The aim of this study was to evaluate the effect of sanguiin H-6 and lambertianin C fractionated from cloudberry seeds, on the MRSA growth, and as treatment of a MRSA biofilm development in different growth media in vitro and in vivo by using a murine wound infection model where sanguiin H-6 and lambertianin C were used to prevent the MRSA infection. Sanguiin H-6 and lambertianin C inhibited the in vitro biofilm development and growth of MRSA. Furthermore, sanguiin H-6 showed significant anti-MRSA effect in the in vivo wound model. Our study shows the possible use of sanguiin H-6 as a preventive measure in surgical sites to avoid postoperative infections, whilst lambertianin C showed no anti-MRSA activity.

scholarly journals Efficacy of NZ2114, a Novel Plectasin-Derived Cationic Antimicrobial Peptide Antibiotic, in Experimental Endocarditis Due to Methicillin-Resistant Staphylococcus aureus

2011 ◽  
Vol 55 (11) ◽  
pp. 5325-5330 ◽  
Author(s):  
Yan Q. Xiong ◽  
Wessam Abdel Hady ◽  
Antoine Deslandes ◽  
Astrid Rey ◽  
Laurent Fraisse ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Maximum Effect ◽  
Peptide Antibiotic ◽  
Time Curve ◽  
Cationic Antimicrobial Peptide ◽  
Unbound Fraction ◽  
Methicillin Resistant ◽  
Content Type ◽  
Conventional Antibiotics

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.

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