Use of in Vitro Critical Inhibitory Concentration, a Novel Approach to Predict in Vivo Synergistic Bactericidal Effect of Combined Amikacin and Piperacillin Against Pseudomonas aeruginosa in a Systemic Rat Infection Model

2006 ◽  
Vol 23 (4) ◽  
pp. 729-741 ◽  
Author(s):  
Eli Chan ◽  
Shufeng Zhou ◽  
Sahasranaman Srikumar ◽  
Wei Duan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Bactericidal Effect ◽  
Infection Model ◽  
Novel Approach

scholarly journals Preclinical In Vitro and In Vivo Characterization of the Fully Human Monoclonal IgM Antibody KBPA101 Specific for Pseudomonas aeruginosa Serotype IATS-O11

2010 ◽  
Vol 54 (6) ◽  
pp. 2338-2344 ◽  
Author(s):  
Michael P. Horn ◽  
Adrian W. Zuercher ◽  
Martin A. Imboden ◽  
Michael P. Rudolf ◽  
Hedvika Lazar ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Treatment Options ◽  
Human Monoclonal Antibody ◽  
Human Monocyte ◽  
Peripheral Blood Lymphocytes ◽  
Infection Model ◽  
High Avidity ◽  
Burn Wound

ABSTRACT Pseudomonas aeruginosa infection in ventilator-associated pneumonia is a serious and often life-threatening complication in intensive care unit patients, and new treatment options are needed. We used B-cell-enriched peripheral blood lymphocytes from a volunteer immunized with a P. aeruginosa O-polysaccharide-toxin A conjugate vaccine to generate human hybridoma cell lines producing monoclonal antibodies specific for individual P. aeruginosa lipopolysaccharide serotypes. The fully human monoclonal antibody secreted by one of these lines, KBPA101, is an IgM/κ antibody that binds P. aeruginosa of International Antigenic Typing System (IATS) serotype O11 with high avidity (5.81 × 107 M−1 ± 2.8 × 107 M−1) without cross-reacting with other serotypes. KBPA101 specifically opsonized the P. aeruginosa of IATS O11 serotype and mediated complement-dependent phagocytosis in vitro by the human monocyte-like cell line HL-60 at a very low concentration (half-maximal phagocytosis at 0.16 ng/ml). In vivo evaluation of KBPA101 demonstrated a dose-response relationship for protection against systemic infections in a murine burn wound sepsis model, where 70 to 100% of animals were protected against lethal challenges with P. aeruginosa at doses as low as 5 μg/animal. Furthermore, a high efficacy of KBPA101 in protection from local respiratory infections in an acute lung infection model in mice was demonstrated. Preclinical toxicology evaluation on human tissue, in rabbits, and in mice did not indicate any toxicity of KBPA101. Based on these preclinical findings, the first human clinical trials have been initiated.

scholarly journals 1244. Assessment of the In Vivo Activity of Human-Simulated Exposure of WCK 4282 (High Dose Cefepime [FEP]-Tazobactam [TZB]) against Enterobacterales (EB) and Pseudomonas aeruginosa (PA) in the Neutropenic Murine Thigh Infection Model

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S640-S641
Author(s):  
Christian M Gill ◽  
Kamilia Abdelraouf ◽  
David P Nicolau
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Bacterial Suspension ◽  
Infection Model ◽  
High Dose ◽  
Comparative Efficacy ◽  
Research Support ◽  
Variable Activity

Abstract Background Carbapenems are often used for infections due to extended-spectrum-β-lactamase (ESBL) and cephalosporinase (CSase)-producers. As increased carbapenem utilization is associated with the development of carbapenem resistance, antimicrobial stewardship has targeted non-carbapenem options. WCK 4282 (FEP 2 g-TZB 2 g) offers pharmacodynamically optimized TZB exposure and demonstrated potent activity in vitro against ESBL-phenotype isolates. We describe the pharmacodynamics of a WCK 4282 human-simulated regimen (HSR) in the neutropenic murine thigh model. Methods 19 clinical strains harboring ESBLs or CSase (EB; n=8 and PA; n=4) or serine-carbapenemases (EB; KPC n=4 or OXA-48-like n=3) were tested in vivo. Per CLSI, 19, 18, and 17 isolates were cefepime, ceftolozane/tazobactam, and piperacillin/tazobactam (TZP) non-susceptible, respectively. Thighs of neutropenic, female, CD-1 mice (3 per group) were inoculated with ~107 CFU/mL of bacterial suspension 2 h prior to dosing. Mice received WCK 4282 HSR, FEP HSR, or saline (controls) for 24 h. WCK 4282 HSR and FEP HSR provided plasma exposures in mice that were similar in f%T > MIC and fAUC to FEP-TZB 2 g-2 g and FEP 2 g, respectively, as IV infusions over 1.5 h q8h in humans. Bacterial densities and their changes at 24 h relative to 0 h controls were determined to assess efficacy and reported as mean±SD log10 CFU/thigh. Results Bacterial burdens were 5.81±0.36 at 0 h and 9.29±0.88 at 24 h in untreated controls. WCK 4282 produced potent activity against ESBL/CSase producing EB and PA with WCK 4282 MIC ≤ 16 mg/L; mean change in log10 CFU from 0 h was -1.70±0.77, while growth was observed with FEP alone. WCK 4282 produced variable activity against OXA-48-like harboring EB. Against KPC-harboring EB, WCK 4282 produced stasis to growth. Mean Log10 CFU changes are reported in Table 1 and Figure 1. Table 1. Comparative efficacy of FEP HSR and WCK 4282 HSR by genotypic β-lactamase Figure 1. Mean Change in log10CFU/thigh for 24 h controls, FEP HSR, and WCK 4282 HSR across the tested MIC distribution. Conclusion WCK 4282, a novel TZB containing regimen, resulted in enhance in vitro potency against ESBL/CSase and OXA-48-like producers. Humanized exposures of WCK 4282 produced substantial kill in vivo against ESBL/CSase producers with MICs ≤ 16 mg/L including FEP resistant/TZP non-susceptible PA. These data support further evaluations of WCK 4282 as a carbapenem-sparing regimen for ESBL/cephalosporinase harboring strains. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)

scholarly journals In vivo activity of human-simulated regimens of imipenem alone and in combination with relebactam against Pseudomonas aeruginosa in the murine thigh infection model

2020 ◽  
Author(s):  
Sergio Reyes ◽  
Kamilia Abdelraouf ◽  
David P Nicolau
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Clinical Utility ◽  
Infection Model ◽  
Treatment Groups ◽  
Log Reduction ◽  
Wide Range ◽  
To Receive ◽  
Inhibitor Combination

Abstract Background Imipenem/relebactam is a carbapenem/β-lactamase inhibitor combination with in vitro activity against Pseudomonas aeruginosa and Enterobacterales, including KPC producers. Objectives To provide translational data to support the clinical utility of the imipenem/relebactam 500/250 mg q6h regimen using a human-simulated regimen (HSR) of imipenem/relebactam, compared with imipenem alone, against a phenotypically and genotypically diverse population of P. aeruginosa. Methods Twenty-nine P. aeruginosa isolates, including KPC (n = 6), PDC (n = 9), PAO (n = 4), GES (n = 5) and VIM (n = 1) producers, were used for the in vivo efficacy studies. Neutropenic mice were thigh-inoculated and randomized to receive HSRs of either imipenem 500 mg q6h, imipenem 1 g q8h, imipenem/relebactam 500/250 mg q6h or saline. Results Twenty-seven of the 29 isolates examined were imipenem resistant, with 24/29 isolates showing imipenem MICs of ≥32 mg/L. The addition of relebactam decreased the MICs up to 64-fold; imipenem/relebactam MICs ranged from 0.25 to >32 mg/L. Efficacies of the imipenem monotherapies and the imipenem/relebactam therapy were comparable for the two imipenem-susceptible organisms. Among the imipenem-resistant isolates, an increased mean growth was observed in the imipenem 500 mg q6h HSR and 1 g q8h HSR treatment groups of 1.31 ± 1.01 and 0.18 ± 1.67 log10 cfu/thigh, respectively. In contrast, a ≥2 log reduction in bacterial density was observed in 27/29 (93%) of the imipenem-resistant isolates subjected to imipenem/relebactam 500/250 mg q6h HSR. Conclusions The imipenem/relebactam 500/250 mg q6h HSR demonstrated superior in vivo activity compared with the conventionally employed imipenem regimens against MDR P. aeruginosa over a wide range of imipenem/relebactam MICs.

scholarly journals The ThiL enzyme is a valid antibacterial target essential for both thiamine biosynthesis and salvage pathways in Pseudomonas aeruginosa

2020 ◽  
Vol 295 (29) ◽  
pp. 10081-10091
Author(s):  
Hyung Jun Kim ◽  
Hyunjung Lee ◽  
Yunmi Lee ◽  
Inhee Choi ◽  
Yoonae Ko ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Drug Target ◽  
Biochemical Properties ◽  
Thiamine Pyrophosphate ◽  
Infection Model ◽  
Screening Assay ◽  
Antibiotic Development ◽  
Thiamine Biosynthesis

Thiamine pyrophosphate (TPP) is an essential cofactor for various pivotal cellular processes in all living organisms, including bacteria. Thiamine biosynthesis occurs in bacteria but not in humans; therefore, the enzymes in this pathway are attractive targets for antibiotic development. Among these enzymes, thiamine monophosphate kinase (ThiL) catalyzes the final step of this pathway, phosphorylating thiamine monophosphate to produce TPP. Here, we extensively investigated ThiL in Pseudomonas aeruginosa, a major pathogen responsible for hospital-acquired infections. We demonstrate that thiL deletion abolishes not only thiamine biosynthesis but also thiamine salvage capability and results in growth defects of the ΔthiL strain even in the presence of thiamine derivatives, except for TPP. Most importantly, the pathogenesis of the ΔthiL strain was markedly attenuated, compared with that of WT cells, with lower inflammatory cytokine induction and 103–104-fold decreased bacterial loads in an in vivo infection model in which the intracellular TPP level was in the submicromolar range. To validate P. aeruginosa ThiL (PaThiL) as a drug target, we further characterized its biochemical properties, determining a Vmax of 4.0 ± 0.2 nmol·min−1 and Km values of 111 ± 8 and 8.0 ± 3.5 μm for ATP and thiamine monophosphate, respectively. An in vitro small-molecule screening assay identified PaThiL inhibitors including WAY213613, a noncompetitive inhibitor with a Ki value of 13.4 ± 2.3 μm and potential antibacterial activity against P. aeruginosa. These comprehensive biological and biochemical results indicate that PaThiL represents a potential drug target for the development of an augmented repertoire of antibiotics against P. aeruginosa.

scholarly journals The Novel β-Lactam Enhancer Zidebactam Augments theIn VivoPharmacodynamic Activity of Cefepime in a Neutropenic Mouse LungAcinetobacter baumanniiInfection Model

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
S. S. Bhagwat ◽  
H. Periasamy ◽  
S. S. Takalkar ◽  
S. R. Palwe ◽  
H. N. Khande ◽  
...  
Keyword(s):  
Bactericidal Effect ◽  
Multidrug Resistant ◽  
Mouse Lung ◽  
Infection Model ◽  
Bactericidal Action ◽  
Content Type ◽  
Time Kill ◽  
The Impact

ABSTRACTWCK 5222 is a combination of cefepime and the high-affinity PBP2-binding β-lactam enhancer zidebactam. The cefepime-zidebactam combination is active against multidrug-resistant Gram-negative bacteria, including carbapenemase-expressingAcinetobacter baumannii. The mechanism of action of the combination involves concurrent multiple penicillin binding protein inhibition, leading to the enhanced bactericidal action of cefepime. The aim of the present study was to assess the impact of the zidebactam-mediated enhancedin vitrobactericidal action in modulating the percentage of the time that the free drug concentration remains above the MIC (percentfT>MIC) for cefepime required for thein vivokilling ofA. baumannii. Cefepime and cefepime-zidebactam MICs were comparable and ranged from 2 to 16 mg/liter for theA. baumanniistrains (n = 5) employed in the study. Time-kill studies revealed the improved killing of these strains by the cefepime-zidebactam combination compared to that by the constituents alone. Employing a neutropenic mouse lung infection model, exposure-response analyses for all theA. baumanniistrains showed that the cefepimefT>MIC required for 1-log10kill was 38.9%. In the presence of a noneffective dose of zidebactam, the cefepimefT>MIC requirement dropped significantly to 15.5%, but it still rendered a 1-log10kill effect. Thus, zidebactam mediated the improvement in cefepime’s bactericidal effect observed in time-kill studies, manifestedin vivothrough the lowering of cefepime’s pharmacodynamic requirement. This is a first-ever study demonstrating a β-lactam enhancer role of zidebactam that helps augment thein vivoactivity of cefepime by reducing the magnitude of its pharmacodynamically relevant exposures againstA. baumannii.

scholarly journals Synergistic Activity of Berberine with Azithromycin against Pseudomonas Aeruginosa Isolated from Patients with Cystic Fibrosis of Lung In Vitro and In Vivo

2017 ◽  
Vol 42 (4) ◽  
pp. 1657-1669 ◽  
Author(s):  
YongTao Li ◽  
JianRong Huang ◽  
LanJuan Li ◽  
LinSheng Liu
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Lung Infection ◽  
Extracellular Dna ◽  
Pcr Analysis ◽  
Infection Model ◽  
Synergistic Activity ◽  
Time Kill

Background/Aims: Pseudomonas aeruginosa (PA) is one of the major opportunistic pathogens which can cause chronic lung infection of cystic fibrosis (CF). The formation of PA biofilm promotes CF development and restricts the antimicrobial efficacies of current antibiotics. Methods: The antimicrobial effects of azithromycin (AZM) and berberine (BER) alone and in combination were evaluated using microdilution method, checkerboard assay, time-kill test, qRT-PCR analysis and absorption method. The treatments of AZM and/or BER were further evaluated in an animal lung infection model via observing survival rate, bacterial burden and histopathology of lung, the levels of pro-/anti-inflammatory cytokines. Results: AZM-BER were demonstrated to be synergistic against ten clinical PA isolates as well as the standard reference PA ATCC27853, in which PA03 was the most susceptible isolate to AZM-BER with FICI of 0.13 and chosen for subsequent experiments. The synergism of AZM-BER was further confirmed against PA03 in time-kill test and scanning electron microscope (SEM) at their concentrations showing synergism. In PA03, we found that AZM-BER could significantly attenuate productions of a series of virulence factors including alginate, LasA protease, LasB protease, pyoverdin, pyocyanin, chitinase as well as extracellular DNA, and remarkably inhibit the levels of quorum sensing (QS) molecules and the expressions of lasI, lasR, rhlI, rhlR at 1/2×MIC, 1×MIC and 2×MIC. In the infection model, the mice survival were increased markedly, the inflammations of infected lungs were improved greatly along with reduced IL-6, IL-8 and ascended IL-10 at 0.8 mg/kg of AZM combined with 3.2 mg/kg of BER. Conclusion: BER might be a promising synergist to enhance the antimicrobial activity of AZM in vitro and in vivo.

scholarly journals Phenotypic diversification in vivo: Pseudomonas aeruginosa gacS− strains generate small colony variants in vivo that are distinct from in vitro variants

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3699-3709 ◽  
Author(s):  
Lisa K. Nelson ◽  
M. Mark Stanton ◽  
Robyn E. A. Elphinstone ◽  
Janessa Helwerda ◽  
Raymond J. Turner ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenotypic Variation ◽  
Antimicrobial Agents ◽  
Mucosal Surface ◽  
Infection Model ◽  
Bacterial Survival ◽  
Small Colony Variants ◽  
Small Colony

Pseudomonas aeruginosa has long been known to produce phenotypic variants during chronic mucosal surface infections. These variants are thought to be generated to ensure bacterial survival against the diverse challenges in the mucosal environment. Studies have begun to elucidate the mechanisms by which these variants emerge in vitro; however, too little information exists on phenotypic variation in vivo to draw any links between variants generated in vitro and in vivo. Consequently, in this study, the P. aeruginosa gacS gene, which has previously been linked to the generation of small colony variants (SCVs) in vitro, was studied in an in vivo mucosal surface infection model. More specifically, the rat prostate served as a model mucosal surface to test for the appearance of SCVs in vivo following infections with P. aeruginosa gacS− strains. As in in vitro studies, deletion of the gacS gene led to SCV production in vivo. The appearance of these in vivo SCVs was important for the sustainability of a chronic infection. In the subset of rats in which P. aeruginosa gacS− did not convert to SCVs, clearance of the bacteria took place and healing of the tissue ensued. When comparing the SCVs that arose at the mucosal surface (MS-SCVs) with in vitro SCVs (IV-SCVs) from the same gacS− parent, some differences between the phenotypic variants were observed. Whereas both MS-SCVs and IV-SCVs formed dense biofilms, MS-SCVs exhibited a less diverse resistance profile to antimicrobial agents than IV-SCVs. Additionally, MS-SCVs were better suited to initiate an infection in the rat model than IV-SCVs. Together, these observations suggest that phenotypic variation in vivo can be important for maintenance of infection, and that in vivo variants may differ from in vitro variants generated from the same genetic parent.

scholarly journals A Galleria mellonella infection model reveals double and triple antibiotic combination therapies with enhanced efficacy versus a multidrug-resistant strain of Pseudomonas aeruginosa

2014 ◽  
Vol 63 (7) ◽  
pp. 945-955 ◽  
Author(s):  
Jessica Krezdorn ◽  
Sophie Adams ◽  
Peter J. Coote
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Resistant Strain ◽  
Galleria Mellonella ◽  
Multidrug Resistant ◽  
Therapeutic Benefit ◽  
Infection Model ◽  
Combination Therapies ◽  
Multidrug Resistant Strain

The aim of this study was to compare the inhibitory effect of antibiotic combinations in vitro with efficacy in Galleria mellonella larvae in vivo to identify efficacious combinations that target Pseudomonas aeruginosa. P. aeruginosa NCTC 13437, a multidrug-resistant strain resistant to β-lactams and aminoglycosides, was used. Susceptibility to cefotaxime, piperacillin, meropenem, amikacin, levofloxacin and colistin alone, or in dual or triple combinations, was measured in vitro via a 24 h time-kill assay. In vitro results were then compared with the efficacy of the same dual or triple antibiotic combinations versus G. mellonella larvae infected with P. aeruginosa. G. mellonella haemolymph burden of P. aeruginosa was determined over 96 h post-infection and treatment with the most potent combination therapies. Many dual and triple combinations of antibiotics displayed synergistic inhibition of multidrug-resistant P. aeruginosa in vitro. There was little correlation between combinations that were synergistic in vitro and those that showed enhanced efficacy in vivo versus infected G. mellonella larvae. The most potent dual and triple combinations in vivo were cefotaxime plus piperacillin, and meropenem plus piperacillin and amikacin, respectively. Fewer combinations were found to offer enhanced therapeutic benefit in vivo compared with in vitro. The therapeutic benefit arising from treatment with antibiotic combinations in vivo correlated with reduced larval burden of P. aeruginosa. This study has identified antibiotic combinations that merit further investigation for their clinical potential and has demonstrated the utility of using G. mellonella to screen for novel antibiotic treatments that demonstrate efficacy in vivo.

scholarly journals Contribution of swarming motility to dissemination in a Pseudomonas aeruginosa murine skin abscess infection model

2020 ◽  
Author(s):  
Shannon R Coleman ◽  
Daniel Pletzer ◽  
Robert E W Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Load ◽  
Infection Model ◽  
Swarming Motility ◽  
Semisolid Medium ◽  
Low Concentrations ◽  
Complex Adaptive

Abstract Swarming motility in Pseudomonas aeruginosa is a multicellular adaptation induced by semisolid medium with amino acids as a nitrogen source. By phenotypic screening, we differentiated swarming from other complex adaptive phenotypes, such as biofilm formation, swimming and twitching, by identifying a swarming-specific mutant in ptsP, a metabolic regulator. This swarming-deficient mutant was tested in an acute murine skin abscess infection model. Bacteria were recovered at significantly lower numbers from organs of mice infected with the ∆ptsP mutant. We also tested the synthetic peptide 1018 for activity against different motilities and efficacy in vivo. Treatment with 1018 mimicked the phenotype of the ∆ptsP mutant in vitro, as swarming was inhibited at low concentrations (<2 μg/mL) but not swimming or twitching, and in vivo, as mice had a reduced bacterial load recovered from organs. Therefore, PtsP functions as a regulator of swarming, which in turn contributes to dissemination and colonization in vivo.

scholarly journals A preliminary study of in vitro and in vivo synergistic effects of ciprofloxacin and D-tyrosine against Pseudomonas aeruginosa isolates

2020 ◽  
Vol 19 (8) ◽  
pp. 1731-1736
Author(s):  
Huirong Li ◽  
Wei Jiang ◽  
Xiaoshuang He ◽  
Mengting Chen
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Synergistic Effects ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Infection Model ◽  
Antimicrobial Effects ◽  
Kill Curve ◽  
Zebrafish Infection

Purpose: To investigate the synergistic antimicrobial effects of ciprofloxacin and D-tyrosine against drug-resistant bacteria.Method: The antimicrobial effects of ciprofloxacin and D-tyrosine on clinical isolates of multidrugresistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) no. 3556 were determined in vitro based on time-kill curve, and in vivo in P. aeruginosa-zebrafish infection model. Furthermore, 30 clinical isolates of multidrug-resistant P. aeruginosa were used in vitro to ascertain the synergistic effect of the two agents.Results: Combined use of ciprofloxacin and D-tyrosine produced synergistic effects against the clinical isolate of P. aeruginosa no. 3556 in vitro and in vivo. Synergism occurred in 96.67 % (95 % CI, range 83.33 - 99.41 %) of the clinical isolates, and ciprofloxacin dose was reduced in 90 % (95 % CI, range 74.38 - 96.54 %) of the clinical isolates in vitro.Conclusion: These preliminary results suggest that the combination of ciprofloxacin and D-tyrosine is a promising therapeutic strategy against MDR P. aeruginosa infections. Keywords: Ciprofloxacin, D-tyrosine, Synergistic, P. aeruginosa, Zebrafish infection model, Time-killing curve

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