Therapeutic drug monitoring of posaconazole in patients with acute myeloid leukemia or myelodysplastic syndrome.

Posaconazole is a broad-spectrum triazole antifungal available as an oral suspension. Pharmacokinetic data showed a high variability of plasma posaconazole concentrations (PPCs) in patients, suggesting a potential interest in drug monitoring. The aim of our prospective study was to measure the PPCs in prophylactically treated patients to evaluate the impact of different factors on these concentrations. In 40 patients treated prophylactically with posaconazole for acute myeloid leukemia or myelodysplastic syndrome between February 2009 and August 2010, PPCs were measured at day 7 of treatment and then twice weekly. Demographic data, clinical data (including gastrointestinal disorders, comedications, and treatment compliance), caloric and fat intake, and biological data were collected and evaluated. We obtained 275 measurements of PPCs, with a median of 430 ng/ml. PPCs were significantly lower in patients with mucositis (P < 0.001), nausea (P = 0.03), diarrhea (P = 0.03), or vomiting (P = 0.05). PPCs were higher in patients with a higher caloric intake (P = 0.02), while the proportion of fat intake had no influence on PPCs (P = 0.84). The concomitant use of proton pump inhibitors decreased the PPCs (P = 0.02), while the use of tacrolimus increased the PPC (P = 0.03). In the multivariate analysis, the factors influencing the PPCs independently were the concomitant use of tacrolimus (P < 0.001), the presence of mucositis (P = 0.01), and food intake (P = 0.02). Our study confirmed the high variability of posaconazole bioavailability and showed the significant influence of gastrointestinal disorders, food intake, and concomitant medication on the PPCs. However, the optimal PPCs still remain to be defined and correlated with clinical efficacy.

A prospective, randomized study of pefloxacin versus teicoplanin in the treatment of gram-positive coccal infections in cancer patients: early termination due to emergence of resistance to fluoroquinolones.

A randomized prospective study comparing pefloxacin to teicoplanin in the treatment of gram-positive infections in cancer patients was prematurely terminated because of the emergence of pefloxacin resistance associated with oxacillin resistance in Staphylococcus aureus and coagulase-negative staphylococci. Among 56 patients evaluated for efficacy (26 pefloxacin and 30 teicoplanin) and infected with bacteria susceptible to both antibiotics, the clinical cure and eradication rates were similar for pefloxacin (80.5% and 77.3% respectively) and teicoplanin (66.6% and 52.2% respectively). The relapse rates (15% and 10% for pefloxacin and teicoplanin respectively) and the overall mortalities within 1 month (42% and 31%) were similar.

Ceftazidime combined with mecillinam: serum bactericidal titres compared with in-vitro synergy against gram-negative bacilli.

In a study of the possible interaction between mecillinam and ceftazidime against Gram-negative bacilli, ten volunteers received on separate days: ceftazidime 20 mg/kg iv in 15 min, mecillinam 10 mg/kg iv in 15 min, or the combination. Blood samples were obtained before and 1 and 6 h after the end of the infusion. Ten strains each of Klebsiella pneumoniae, Serratia marcescens, Citrobacter freundii, Salmonella spp. and Yersinia spp. and nine strains each of Acinetobacter spp., and Pseudomonas aeruginosa were selected. Most of the strains were resistant to ampicillin and cefazolin. Serum levels of ceftazidime and mecillinam were measured by bioassay. Serum bacteriostatic (SBS) and bactericidal (SBA) titration was done in microtitre plates in cation supplemented Mueller-Hinton broth and 50% human serum. Chequerboard titration was also studied to assess in-vitro synergy between ceftazidime and mecillinam in Mueller-Hinton broth with or without 50% serum. The mean serum concentrations (SD) were for mecillinam: 6.1 (1.7) at 1 h, and less than 0.3 at 6 h and for ceftazidime: 36.3 (5.5) at 1 h and less than 5 at 6 h. Identical concentrations were measured for the combination. By chequerboard titration, no synergy occurred for Acinetobacter spp. and Ps. aeruginosa, whereas it was observed in 37/60 (FIC) and 33/60 (FBC) of the strains of other species in Mueller-Hinton; from the strains showing synergy, 28/37 (FIC) and 30/33 (FBC) showed also synergy in Mueller-Hinton with 50% human serum. In SBS and SBA, on the other hand, the combination of mecillinam with ceftazidime showed an additive effect against most Enterobacteriaceae tested, synergy being shown for only 10-35% of tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence and significance of Clostridium difficile in hospitalized cancer patients.

The aim of the study was to assess the incidence and clinical significance of Clostridium difficile in patients in our cancer center. Over a period of seven consecutive months, 557 stools samples obtained from 156 hospitalized cancer patients (37 leukemic patients receiving oral antimicrobial prophylaxis and 119 patients from whom a stool sample was sent to the laboratory) were analyzed for the presence of Clostridium difficile. Clostridium difficile and/or its toxin was recovered from 13 (35%) of the 37 patients receiving oral antimicrobial prophylaxis, and from 15 (12%) of the other 119 patients (p less than 0.05). Isolation of Clostridium difficile was associated with diarrhoea in 13 (46%) of 28 patients but specific treatment was initiated only in 7 (25%) of the 28 patients in whom Clostridium difficile was isolated. The wide distribution of the serotypes identified in our patients does not suggest an epidemic situation in our hospital.