Efficacy of phosphomycin in the control of Escherichia coli infection of broiler chickens

Effects of different broiler production systems on health care costs in the Netherlands

This study analyzed the effects of different broiler production systems on health care costs in the Netherlands. In addition to the conventional production system, the analysis also included 5 alternative animal welfare systems representative of the Netherlands. The study was limited to the most prevalent and economically relevant endemic diseases in the broiler farms. Health care costs consisted of losses and expenditures. The study investigated whether higher animal welfare standards increased health care costs, in both absolute and relative terms, and also examined which cost components (losses or expenditures) were affected and, if so, to what extent. The results show that health care costs represent only a small proportion of total production costs in each production system. Losses account for the major part of health care costs, which makes it difficult to detect the actual effect of diseases on total health care costs. We conclude that, although differences in health care costs exist across production systems, health care costs only make a minor contribution to the total production costs relative to other costs, such as feed costs and purchase of 1-d-old chicks.

Pharmacokinetics of a single bolus intravenous, intramuscular and subcutaneous dose of disodium fosfomycin in horses

Pharmacokinetic parameters of fosfomycin were determined in horses after the administration of disodium fosfomycin at 10 mg/kg and 20 mg/kg intravenously (IV), intramuscularly (IM) and subcutaneously (SC) each. Serum concentration at time zero (C(S0)) was 112.21 +/- 1.27 microg/mL and 201.43 +/- 1.56 microg/mL for each dose level. Bioavailability after the SC administration was 84 and 86% for the 10 mg/kg and the 20 mg/kg dose respectively. Considering the documented minimum inhibitory concentration (MIC(90)) range of sensitive bacteria to fosfomycin, the maximum serum concentration (Cmax) obtained (56.14 +/- 2.26 microg/mL with 10 mg/kg SC and 72.14 +/- 3.04 microg/mL with 20 mg/kg SC) and that fosfomycin is considered a time-dependant antimicrobial, it can be concluded that clinically effective plasma concentrations might be obtained for up to 10 h administering 20 mg/kg SC. An additional predictor of efficacy for this latter dose and route, and considering a 12 h dosing interval, could be area under the curve AUC(0-12)/MIC(90) ratio which in this case was calculated as 996 for the 10 mg/kg dose and 1260 for the 20 mg/kg dose if dealing with sensitive bacteria. If a more resistant strain is considered, the AUC(0-12)/MIC(90) ratio was calculated as 15 for the 10 mg/kg dose and 19 for the 20 mg/kg dose.

Pharmacokinetics of disodium-fosfomycin in mongrel dogs

Pharmacokinetic variables of fosfomycin were determined after administration of buffered disodium-fosfomycin intravenously (IV), intramuscularly (IM), subcutaneously (SC) and orally (PO), in mongrel dogs, at 40 and 80 mg/kgday for three days. Renal integrity was also assessed by measuring key serum variables. Day 1, day 2 and day 3 plasma concentration vs. time profiles were undistinguishable, but there appears to be a lineal increase in serum concentrations vs. time with the dose. A non-accumulative kinetic behavior was observed after three days with both doses and most pharmacokinetic variables remain unaltered. Considering a MIC range from 1 mirog/mL to 16 microg/mL of fosfomycin in serum for sensitive bacteria, and a negligible plasma protein binding of fosfomycin (<0.5%), useful plasma concentrations can only be achieved after the SC injection of 80 mg/kg every 12h, having a C(max)=18.96+/-0.3 microg/mL; a T(1/2beta)=2.09+/-0.06 microg/mL and a bioavailability of 84-85%. No alterations were observed in serum variables of kidney-related biochemical values.

Intravenous and intramuscular pharmacokinetics of a single-daily dose of disodium-fosfomycin in cattle, administered for 3 days

Pharmacokinetic parameters of fosfomycin in cattle were determined after administration of buffered disodium fosfomycin either intravenously (i.v.) or intramuscularly (i.m.) at a dose of 20 mg/kg/day for 3 days. Calculated concentrations at time zero and maximum serum concentrations were 34.42 and 10.18 mug/mL, respectively. The variables determined, the elimination half-life of the drug remained unchanged during the 3 days ( = 1.33 +/- 0.3 h for the i.v. route and = 2.17 +/- 0.4 h for the i.m. route). Apparent volumes of distribution suggest moderated distribution out of the central compartment (V(darea) = 673 mL +/- 27 mL/kg and V(dss) = 483 +/- 11 mL/kg). Bioavailability after i.m. administration was 74.52%. Considering fosfomycin as a time-dependent antibacterial drug, plasma concentration vs. time profiles obtained in this study, suggest that clinically effective plasma concentrations of fosfomycin could be obtained for up to 8 h following i.v. administration and approximately 10 h after i.m. injection of 20 mg/kg, for susceptible bacteria. In addition to residue studies in milk and edible tissues, a series of clinical assessments, using fosfomycin at 20 mg/kg b.i.d. or t.i.d. are warranted before this antibacterial drug should be considered for use in cattle.

Efficacy of calcium fosfomycin for the treatment of experimental infections of broiler chickens with Escherichia coli O78:K80

Two trials were made to assess the efficacy of including calcium fosfomycin in the drinking water or in the feed for four days to control the adverse effects of experimentally induced colibacillosis in broiler chickens. Trial 1 had five groups of 15 chicks each: one group of negative controls; an untreated infected control group and three groups treated with 50, 100 or 200 ppm of calcium fosfomycin in drinking water. Trial 2 had the same groups but the antibiotic was incorporated into the feed. The chickens were infected via their air sacs with 1.7 x 10(8) - 3.6 x 10(8) CFU/chick of Escherichia coli O78:K80. The morbidity and mortality, a score for the gross lesions, the relative weight of the liver and spleen, performance and re-isolation of the challenge bacteria were recorded. Calcium fosfomycin in the drinking water controlled the colibacillosis, particularly in the group treated with 200 ppm. However, no effect of the antibiotic was seen when calcium fosfomycin was incorporated into the feed, the mortality, score of lesions and re-isolation of E. coli from the organs in the three treated groups being similar to those for the infected unmedicated group. The amount of antibiotic ingested in trial I was three times more than in trial 2. These results suggest that calcium fosfomycin is best used in the drinking water for the treatment of colibacillosis.

Control of Salmonella enteritidis phage type 4 experimental infection by fosfomycin in newly hatched chicks

One hundred and twenty 1-day-old broiler chickens were divided into four groups: group I unmedicated and orally challenged with 1.5 x 10(8) cfu of Salmonella enteritidis phage type 4; group F infected and treated with 300 ppm of fosfomycin in their drinking water; group CF uninfected and treated, and group C maintained as a control group. Their performance, clinical signs, S. enteritidis PT4 reisolation and biochemistry variables were compared. Group F showed fewer symptoms and gross lesions than those from group 1. Fosfomycin treatment at 300 ppm improved body weight at 7 days of age by 42.3%. S. enteritidis PT4 reisolation in group I was higher than in the treated group, but total decontamination of challenged birds was not achieved. There was an increase in the levels of total protein and globulins in group I but not in the treated group. Fosfomycin caused no adverse effects on chickens from group CF, assessed by performance and biochemical variables. The results indicate that fosfomycin could be used in the treatment of S. enteritidis PT4 experimental infection.