Publications by authors named "Sebastian G Wicha"

Background: MDR Gram-negative bacteria, such as ESBL-producing and carbapenemase-producing Klebsiella pneumoniae, represent major global health threats. Treatment options are limited due to increasing resistance and slowed development of novel antimicrobials, making it necessary to apply effective combination therapies based on approved antibiotics.

Objectives: To quantitatively evaluate the synergistic potential of meropenem and fosfomycin against carbapenem-resistant K.

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New antimalarial combination therapies with novel modes of action are required to counter the emergence and spread of drug resistance against existing therapeutics. Here, we present a study to evaluate the preventive activity of a combination of clinical antimalarial drug candidates, cabamiquine and ganaplacide, that have multistage activity against the liver and blood stages of infection. Cabamiquine (DDD107498, M5717) inhibits parasite protein synthesis, and ganaplacide (KAF156) inhibits protein trafficking, blocks the establishment of new permeation pathways, and causes endoplasmic reticulum expansion.

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  • The study investigates the effects of cabamiquine and pyronaridine on the P. falciparum malaria parasite, looking at their performance as standalone treatments and in combination therapy.
  • Using field isolates and a pharmacometrics model, researchers create an interaction map to simulate effective clinical dose ratios for these antimalarials.
  • Results indicate that while pyronaridine alone is less effective, the combination of cabamiquine and pyronaridine significantly improves parasite killing, suggesting the methodology can aid in developing new malaria treatments.
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Objectives: Piperacillin (PIP)/tazobactam is a frequently prescribed antibiotic; however, over- or underdosing may contribute to toxicity, therapeutic failure, and development of antimicrobial resistance. An external evaluation of 24 published PIP-models demonstrated that model-informed precision dosing (MIPD) can enhance target attainment. Employing various candidate models, this study aimed to assess the predictive performance of different MIPD-approaches comparing (i) a single-model approach, (ii) a model selection algorithm (MSA) and (iii) a model averaging algorithm (MAA).

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  • Meropenem penetration into cerebrospinal fluid (CSF) varies greatly among individuals, raising concerns about effective treatment, especially when using intermittent versus continuous infusion methods.
  • This study compared the pharmacokinetics of meropenem in CSF of critically ill patients using both administration methods, assessing 16 patients with various infections.
  • Results showed no significant difference in drug concentrations or target attainment in CSF between continuous infusion and intermittent infusion, indicating that continuous administration may not enhance drug penetration as previously thought.
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Objectives: Temocillin, a carbapenem-sparing β-lactam antibiotic, is commonly used at the standard 4 g/day dosage for treating complicated urinary tract infections (cUTIs). However, pharmacokinetic/pharmacodynamic (PK/PD) data supporting this regimen is limited. This study evaluated the plasma pharmacokinetics (PK) and PTA of temocillin in non-critically ill cUTI patients with varying degrees of renal insufficiency (RI).

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Background: Infliximab, an anti-tumor necrosis factor monoclonal antibody, has revolutionized the pharmacological management of immune-mediated inflammatory diseases (IMIDs). This position statement critically reviews and examines existing data on therapeutic drug monitoring (TDM) of infliximab in patients with IMIDs. It provides a practical guide on implementing TDM in current clinical practices and outlines priority areas for future research.

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  • Linezolid is a special antibiotic used when other antibiotics don't work, but it can cause side effects like low platelet counts (thrombocytopenia).
  • Researchers studied patients taking Linezolid to find out how often these side effects happen and what might increase the risk, especially with longer treatments and higher drug levels in the blood.
  • They found that patients on Linezolid for more than 10 days or with high blood levels were more likely to have problems, and they suggested ways to monitor and adjust treatment to keep patients safe.
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The FDA announced a boxed warning for tigecycline due to progression of infections caused by Gram-negative bacteria and increased risk of mortality during treatment. Plasma exposure of tigecycline might not prevent bacteraemia in these cases from the focuses. Hence, we evaluated intensified dosing regimens and breakpoints that might suppress bloodstream infections, caused by progression of infection by e.

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  • - This study examined how albumin supplementation affects the pharmacokinetics (PK) of the drug piperacillin/tazobactam in severely burned patients in the ICU, focusing on both total and unbound drug concentrations.
  • - Seven patients with significant burn injuries were monitored before and after receiving albumin along with their scheduled piperacillin/tazobactam administration, utilizing IV microdialysis and arterial plasma sampling for accurate PK analysis.
  • - Results indicated that while there was a slight numerical increase in total and unbound drug exposure after albumin substitution, overall, albumin had little impact on the PK of piperacillin/tazobactam, suggesting that further research is needed for drugs that are more
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Mechanistic understanding of pharmacodynamic interactions is key for the development of rational antibiotic combination therapies to increase efficacy and suppress the development of resistances. Potent tools to provide those insights into pharmacodynamic drug interactions are semi-mechanistic modeling and simulation techniques. This study uses those techniques to provide a detailed understanding with regard to the direction and strength of the synergy of ceftazidime-avibactam and ceftazidime-fosfomycin in a clinical isolate expressing extended spectrum beta-lactamase (CTX-M-15 and TEM-4) and carbapenemase (OXA-244) genes.

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The use of surface-grafted polymer brushes with combined low-fouling and antibacterial functionality is an attractive strategy to fight biofilm formation. This report describes a new styrene derivative combining a quaternary ammonium group with a sulfobetaine group in one monomer. Surface-initiated polymerization of this monomer on titanium and a polyethylene (PE) base material gave bifunctional polymer brush layers.

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Background And Objective: Ceftaroline fosamil is a β-lactam antibiotic approved as a 600 mg twice daily dose (≤1 h infusion, 'standard dosing') or a 600 mg thrice daily dose (2 h infusion) to treat complicated skin and soft tissue infections caused by Staphylococcus aureus (minimum inhibitory concentration [MIC] 2-4 mg/L). We sought to systematically evaluate the relative impact of the three key components of the intensified dosing regimen (i.e.

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The treatment of drug-resistant relies on complex antibiotic therapy. Inadequate antibiotic exposure can lead to treatment failure, acquired drug resistance, and an increased risk of adverse events. Therapeutic drug monitoring (TDM) can be used to optimize the antibiotic exposure.

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  • In acute-on-chronic liver failure (ACLF), how antibiotics like linezolid are dosed is difficult due to altered drug handling in the body.
  • A study compared the pharmacokinetics of linezolid in patients with ACLF undergoing continuous renal replacement therapy to those without liver issues.
  • Results showed that ACLF patients had much lower clearance rates for linezolid, meaning they are at risk of higher drug concentrations, suggesting that careful monitoring and potential dose adjustments are needed to avoid toxicity.
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  • This study looks at how two antibiotics, ceftazidime/avibactam and colistin, work together over time in fighting bacteria that are hard to treat.
  • They used a test called time-kill curves (TKCs) to see how effective these antibiotics are alone and together against certain bacteria.
  • The results showed that when used together, the antibiotics generally worked well without any bad effects, and they helped stop the bacteria from becoming resistant to treatment.
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Background: Combination therapy can increase efficacy of antibiotics and prevent emergence of resistance. Ceftazidime/avibactam and fosfomycin may be empirically combined for this purpose, but a systematic and quantitative evaluation of this combination is needed.

Objectives: In this study, a systematic analysis of the pharmacodynamic interactions of ceftazidime/avibactam and fosfomycin in clinical and isogenic Escherichia coli strains carrying genes coding for several carbapenemases or ESBLs was performed and pharmacodynamic interactions were quantified by modelling and simulations.

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Surface-initiated atom transfer radical polymerization (SI-ATRP) is a powerful tool for grafting functional polymers from metal surfaces. It depends on the immobilization of suitable initiators on the surface before radical polymerization. Herein, we report a set of bifunctional initiators bearing a phosphonic acid group for surface binding and a bromoisobutyramide moiety for SI-ATRP.

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Purpose: Inadequate piperacillin (PIP) exposure in intensive care unit (ICU) patients threatens therapeutic success. Model-informed precision dosing (MIPD) might be promising to individualize dosing; however, the transferability of published models to external populations is uncertain. This study aimed to externally evaluate the available PIP population pharmacokinetic (PopPK) models.

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An adequate covariate selection is a key step in population pharmacokinetic modelling. In this study, the automated stepwise covariate modelling technique ('scm') was compared to full random effects modelling ('frem'). We evaluated the power to identify a 'true' covariate (covariate with highest correlation to the pharmacokinetic parameter), precision, and accuracy of the parameter-covariate estimates.

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Zwitterionic polymer brushes were grafted from bulk polyethylene (PE) by air plasma activation of the PE surface followed by radical polymerization of the zwitterionic styrene derivative (vinylbenzyl)sulfobetaine (VBSB). Successful formation of dense poly-(VBSB)-brush layers was confirmed by goniometry, IR spectroscopy, XPS and ToF-SIMS analysis. The resulting zwitterionic layers are about 50-100 nm thick and cause extremely low contact angles of 10° (water) on the material.

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