Matthias G. Vossen

The SYBR Green I Malaria Drug Sensitivity Assay: Performance in Low Parasitemia Samples

Validation of the sensitivity of the SYBR Green I in vitro test against an enzyme-linked immunosorbent assay (ELISA)-based drug sensitivity assay. Our results suggest that the SYBR Green I assay is a fast and inexpensive malaria drug screening assay for laboratory use. However, because of its lack of sensitivity in whole blood samples its usefulness for testing clinical samples may be limited.

Azithromycin Combination Therapy for the Treatment of Uncomplicated Falciparum Malaria in Bangladesh: An Open-Label Randomized, Controlled Clinical Trial

BACKGROUND In recent studies, the combination of azithromycin and artesunate has proven to be a promising alternative for the treatment of uncomplicated falciparum malaria. METHODS We conducted a randomized, controlled clinical trial assessing the efficacy of azithromycin-artesunate combination therapy. The study was conducted involving 228 patients aged 8-65 years. Patients were randomized to 1 of 2 cohorts at a ratio of 2:1, receiving either azithromycin-artesunate once daily for 3 days (30 mg/kg per day of azithromycin plus 4 mg/kg per day of artesunate) or an adult dose of 80 mg of artemether plus 960 mg of lumefantrine (4 tablets Coartem or the equivalent for children weighing <35 kg) twice daily for 3 days. RESULTS The 42-day cure rate by Kaplan-Meier analysis was 94.6% (95% confidence interval [CI], 89.38%-97.44%) in the azithromycin-artesunate arm and 97.0% (95% CI, 89.45%-99.40%) in the control arm. Fever clearance times and parasite clearance times did not show any differences between the 2 arms (P=.59 and .95, respectively). No serious adverse events were seen, but the percentage of patients who developed any adverse event was higher in the control group (P=.03). CONCLUSIONS Our data suggest that azithromycin-artesunate is an efficacious and well-tolerated treatment for patients with uncomplicated falciparum malaria in Bangladesh.

Effects of Renal Replacement Therapy on Antimicrobial Therapy

Antimicrobial therapy in patients receiving renal replacement therapy (RRT) is challenging due to the varying pharmacokinetic profile of each drug-membrane-technique combination. Renally excreted drugs are usually affected by RRT to a much higher extend than hepatically excreted drugs. However, highly protein bound drugs might be eliminated during RRTs regardless of their usual route of elimination through the formation of a protein membrane within the filter. Beta-lactames pose a good example: most beta-lactames are excreted renally as unchanged drug. However, some betalactames, e.g. flucloxacillin or ceftriaxone adhere to the filter membrane due to their strong protein-drug interaction. Depending on the implemented RRT different administration regimens should be chosen. While beta-lactames may be administered three times daily as well as continuously during continuous RRT, they should be given only once after each hemodialysis session. Aminoglycosides on the other hand should best be given previous to HD to allow for high peak and low through concentrations due to their small therapeutic index and high toxicity. The current Recommendation for glycopeptides in hemodialysis is a post-HD administration. In both groups, aminoglycosides as well as glycopeptides drug monitoring is mandatory. For chinolones the standard dosing intervals should remain unchanged, however they require a significant reduction of the dose, with the exception of moxifloxacin which is excreted hepatically. Until now there are few publications guiding the clinician to the correct dosing schemes in RRT. This review aims to give dosage recommendations for a broad collection of currently used antimicrobial agents and should be applicable for all types of presently employed membranes.

Micafungin plasma levels are not affected by continuous renal replacement therapy – experience in critically ill patients

ABSTRACT Critically ill patients often experience acute kidney injury and the need for renal replacement therapy in the course of their treatment in an intensive care unit (ICU). These patients are at an increased risk for candidiasis. Although there have been several reports of micafungin disposition during renal replacement therapy, to this date there are no data describing the elimination of micafungin during high-dose continuous venovenous hemodiafiltration with modified AN69 membranes. The aim of this prospective open-label pharmacokinetic study was to assess whether micafungin plasma levels are affected by continuous hemodiafiltration in critical ill patients using the commonly employed AN69 membrane. A total of 10 critically ill patients with micafungin treatment due to suspected or proven candidemia were included in this trial. Prefilter/postfilter micafungin clearance was measured to be 46.0 ml/min (±21.7 ml/min; n = 75 individual time points), while hemofilter clearance calculated by the sieving coefficient was 0.0038 ml/min (±0.002 ml/min; n = 75 individual time points). Total body clearance was measured to be 14.0 ml/min (±7.0 ml/min; n = 12). The population area under the curve from 0 to 24 h (AUC0–24) was calculated as 158.5 mg · h/liter (±79.5 mg · h/liter; n = 13). In spite of high protein binding, no dose modification is necessary in patients receiving continuous venovenous hemodiafiltration with AN69 membranes. A dose elevation may, however, be justified in certain cases. (This study has been registered at ClinicalTrials.gov under identifier NCT02651038.)

Doripenem treatment during continuous renal replacement therapy

ABSTRACT Doripenem is a broad-spectrum parenteral carbapenem with enhanced activity against Pseudomonas aeruginosa. While the initial dosing recommendation for renally competent patients and patients undergoing continuous renal replacement therapy (cRRT) was 500 mg every 8 h (q8h), the dose for renally competent patients was updated to 1 g q8h in June 2012. There are no updated data for the dosing of patients on continuous renal replacement therapy. The original dosing regimen for cRRT patients was based on nonseptic patients, while newer publications chose comparatively low target concentrations for a carbapenem. Thus, there is an urgent need for updated recommendations for dosing during cRRT. In the trial presented here, we included 13 oliguric septic patients undergoing cRRT in an intensive care setting. Five patients each were treated with hemodiafiltration or hemodialysis, while three patients received hemofiltration treatment. All patients received 1 g doripenem every 8 h. Doripenem concentrations in the plasma and ultrafiltrate were measured over 48 h. The mean hemofilter clearance was 36.53 ml/min, and the mean volume of distribution was 59.26 liters. The steady-state trough levels were found at 8.5 mg/liter, with no considerable accumulation. Based on pharmacokinetic and pharmacodynamic considerations, we propose a regimen of 1 g q8h, which may be combined with a loading dose of 1.5 to 2 g for critically ill patients. (This study has been registered with EudraCT under registration no. 2009-018010-18 and at ClinicalTrials.gov under registration no. NCT02018939.)

The First Case(s) of Botulism in Vienna in 21 Years: A Case Report

We describe two linked cases of botulinum toxin intoxication to provide the clinician with a better idea about how botulism cases may present since early diagnosis and treatment are crucial in botulism. Botulinum toxin is the strongest neurotoxin known. Methods: We review the available literature, the compiled clinical data, and observations. Results: After a slow onset of clinical signs a married couple living in Vienna presented with dysphagia, difficulties in accommodation, inability to sweat, urinary and stool retention, dizziness, and nausea. They suffered intoxication with botulinum toxin type B. Botulism is a rarely occurring disease in Austria. In the last 21 years there were only twelve reported cases. Conclusion: Both patients went to a general practitioner as well as several specialists before they were sent to and correctly diagnosed at our outpatient department. To avoid long delays between intoxication and diagnosis we think it is crucial to advert to the complex symptoms a nonsevere intoxication with botulinum toxin can produce, especially since intoxications have become rare occurrences in the industrialized societies due to the high quality of industrial food production.

In vitro interaction of dihydroartemisin and lumefantrine in clinical field isolates from Bangladesh

ZusammenfassungArtemether-Lumefantrin wurde im Jahr 2005 als offizielle Standardtherapie für die Behandlung der unkomplizierten Plasmodium falciparum Malaria in Bangladesh eingeführt. Um die Interaktion zwischen Dihydroartemisinin (DHA) und Lumefantrin (LUM) näher zu untersuchen, wurden frische P. falciparum Isolate von Patienten, die mit unkomplizierter falciparum Malaria in der MARIB Feldstation im Bandarban Sadar Hospital in Bangladesh vorstellig wurden, in Checkerboard in vitro Assays getestet. Das Interaktionsverhalten kann mit einer mittleren FIC50 von 0,52 und durchschnittlichen Einzel-FICs zwischen 0,26 und 0,85 als hoch synergistisch beschrieben werden. Die niedrigsten FICs lagen bei 0,41, 0,18, 0,22, 0,15 und 0,11 bei unterschiedlichen Kombinationsverhältnissen. Als optimales Kombinationsverhältnis mit den im Durchschnitt geringsten FICs wurde eine Verhältnis von 1:150 DHA:LUM ermittelt. Auch wenn eine positive Korrelation zwischen den beiden Stoffen Hinweise auf mögliche Kreuzsensibilität gibt, bestätigen unsere Daten eine hoch synergistische Interaktion zwischen DHA und Lumefantrin.SummaryThe combination of artemether and lumefantrine was introduced in 2005 as the official first line therapy for uncomplicated falciparum malaria in Bangladesh. Fresh P. falciparum samples from patients with acute uncomplicated falciparum malaria who presented to the field site at the Bandarban Sadar Hospital in Bangladesh were tested in checkerboard in vitro drug sensitivity assays to assess the interaction between dihydroartemisinin (DHA) and lumefantrine (LUM). Clearly synergistic interactions with an overall mean FIC50 of 0.52 and individual mean FICs between 0.26 and 0.85 were found. Lowest FICs were 0.41, 0.18, 0.22, 0.15 and 0.11 at different combination ratios. The optimal combination ratio of the drug combination indicated by the lowest mean FIC average was found to be 1:150 DHA:LUM. Although activity correlations between DHA and lumefantrine were significant, indicating possible cross sensitivity patterns, our data confirm that artemether-lumefantrine is a highly synergistic drug combination.

Sequential high- and low-dose systemic corticosteroid therapy for severe childhood alopecia areata

Given the limited number of therapeutic options, severe childhood alopecia areata (AA) poses a clinical challenge. The best and most rapid response rates can be achieved with high‐dose systemic corticosteroids, however, relapse following treatment discontinuation is inevitable. Due to systemic side effects, long‐term high‐dose corticosteroid regimens are not feasible. Following initial pulse therapy, continuation of corticosteroid therapy at a dose below the Cushing threshold might be able to suppress disease activity without causing severe side effects.

Single dose pharmacokinetics of cidofovir in continuous venovenous hemofiltration

ABSTRACT Dosage recommendations for cidofovir are available for renally competent as well as impaired patients; however, there are no data for patients undergoing continuous renal replacement therapy. We determined the single-dose concentration-versus-time profile of cidofovir in a critically ill patient undergoing continuous venovenous hemofiltration (CVVH). One dose of 450 mg cidofovir (5 mg/kg) was administered intravenously due to a proven cytomegalovirus (CMV) infection and failure of first-line antiviral therapy. Additionally, 2 g of probenecid was administered orally 3 h prior to and 1 g was administered 2 h as well as 8 h after completion of the infusion. The concentrations of cidofovir in serum and ultrafiltrate were assessed by high-performance liquid chromatography. The peak serum concentration measured at 60 min postinfusion was 28.01 mg/liter at the arterial port. The trough serum level was 19.33 mg/liter at the arterial port after 24 h. The value of the area under the concentration-versus-time curve from 0 to 24 h was 543.8 mg · h/liter. The total body clearance was 2.46 ml/h/kg, and the elimination half-life time was 53.32 h. The sieving coefficient was 0.138 ± 0.022. Total removal of the drug was 30.99% after 24 h. Because of these data, which give us a rough idea of the concentration profile of cidofovir in patients undergoing CVVH, a toxic accumulation of the drug following repeated doses may be expected. Further trials have to be done to determine the right dosage of cidofovir in patients undergoing CVVH to avoid toxic accumulation of the drug.

Gemella morbillorum Bacteremia after Anti-Tumor Necrosis Factor Alpha as Acne Inversa Therapy

ABSTRACT We present a case of fever, brain abscesses, and Gemella morbillorum bacteremia after anti-tumor necrosis factor alpha (TNF-α) therapy in a 21-year-old acne inversa patient currently taking long-term dapsone. To the best of our knowledge, this is the first report describing such a case. During antimicrobial therapy, the patient developed systemic varicella infection with severe thrombocytopenia.