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

Modulatory effect of dietary probiotic and prebiotic supplementation on growth, immuno-biochemical alterations, DNA damage, and pathological changes in E. coli-infected broiler chicks

Avian pathogenic Escherichia coli is one of the principal causes of heavy economic losses to the poultry industry. Little is known about the underlying mechanisms, particularly the potential role of immunoglobulin A and the DNA damage, involving the beneficial effects of dietary supplementation of probiotics and prebiotics in avian colibacillosis. The current study investigated the potential effects of probiotic and prebiotic dietary supplementation on E. coli-infected broiler chicks. A total of 120 1-day-old unsexed Hubbard chicks were divided into six groups: Group 1 was considered as a negative control; Group 2 was supplemented with 1 g/kg feed of Lactobacillus plantarum; Group 3 was supplemented with amylase enzyme; Group 4 served as a positive control infected orally by E. coli O78; Group 5 was supplemented with L. plantarum from 1-day-old chicken and then infected orally with E. coli O78; and Group 6 was supplemented with amylase enzyme from 1-day old chicken and then infected orally with E. coli O78. For all examined groups, the experimental period lasted for 42 days. The E. coli-infected group revealed a decrease in body performance parameters with a significant increase in the liver enzymes and renal function tests. The same group recorded a significant decrease in serum total proteins, albumins, and globulins, and the alteration of immunological parameters, antioxidant enzymes, oxidative stress parameters, and comet assay revealed highly damaged DNA in the liver and the intestine. By histopathological examination, a series of histopathological changes in the liver, the kidney, and the intestine were observed. The infected chick pretreated with probiotics or prebiotics demonstrated an improvement in body performance parameters besides a significant decrease in the hepatic enzymes and renal function tests. We noticed that, in treated groups, there was a significant increase in serum total proteins in the serum albumin and globulin levels, immunological parameters, and antioxidant enzymes. Furthermore, DNA damage and histopathological changes within hepatic, renal, and intestinal tissues were markedly diminished in the treated groups compared with the infected group. We concluded that the adverse effects of E. coli could be modulated through the chemopreventive administration of probiotics and prebiotics.

The effect of a postbiotic produced by stabilized non-viable Lactobacilli on the health, growth performance, immunity, and gut status of colisepticaemic broiler chickens

This work was designed to evaluate the efficacy of a postbiotic compound produced by stabilized non-viable Lactobacilli on the health, growth performance, immunity, and gut status against Escherichia coli (E. coli) challenge of broiler chickens. A total of 400, day-old broiler chicks were allocated into 4 equal groups (1–4) consisting of 100; each assigned into 2 equal replicates (50 each). Chickens in the 1st group were received the dry form of the compound at doses of 1 kg and 0.5 kg/ton feed for starter and grower, and the finisher diets, respectively. Chickens in the 2nd group were given the aqueous form of the compound in a dose of 4 mL/L of the drinking water during the first 3 days of life and at a day before and after each vaccination. Feed and water treatment regimens were administered to chickens in the 3rd group. Group 4 was kept without treatment. Each bird in the 1st, 2nd, 3rd, and 4th group was challenged with E. coli (O78) at 1-week-old. All groups were kept under observation till 5-week-old. Statistical analysis included one-way ANOVA and other methods as described with significant differences at P ≤ 0.05. The results indicated that feed and water treatments with the postbiotic compound induced more significant (P ≤ 0.05) amelioration of a disease picture, enhancement of growth performance, boosting of immune response, improvement of bursa of Fabricius/body weight ratio, and reduction of intestinal coliform count in challenged chickens when compared with challenged non-treated chickens. In conclusion, the postbiotic compound either in a dry and/or an aqueous form is recommended for improving the health, performance, and immunity of colisepticaemic broiler chickens.

Efficacy of Bacillus subtilis and bacitracin methylene disalicylate on growth performance, digestibility, blood metabolites, immunity, and intestinal microbiota after intramuscular inoculation with Escherichia coli in broilers

This experiment was conducted to evaluate the effect of Bacillus subtilis (BS) on broiler performance and health after intramuscular inoculation with E. coli and compare its effect with a growth promoter antibiotic. In a completely randomized design manner, 360 male Ross 308 chicks were divided into 6 treatments and 5 replicates of 12 chicks in each replicate. Experimental treatments included control diet, control + E. coli (0.5 mL of culture containing 108 CFU of E. coli/ml), control + 0.1% BS, control + 0.05% bacitracin methylene disalicylate (BMD), control + E. coli and BS, and control + E. coli and BMD in a factorial arrangement (3 × 2). Addition of BMD or BS to the control diet significantly (P < 0.01) increased body weight and decreased FCR, but E. coli challenge adversely reduced (P < 0.01) body weight and increased FCR, so that the addition of BMD or BS did not compensate growth reduction. E. coli challenged chicks had the lowest vaccine titers for ND, IB, AI, and IBD and the highest were observed in chicks fed BS. The E. coli challenge significantly (P < 0.01) increased albumin, globulin, cholesterol, triglyceride, LDL, ALT, and ALP indices. Addition of BMD and BS decreased albumin and globulin in challenged chick's plasma but had no effect on plasma lipid profile concentration. The E. coli challenge decreased villus height and increased crypt depth and goblet cell numbers significantly (P < 0.01). In birds subjected to BMD or BS, crypt depth decreased and villus height increased (P < 0.01), compared with the control diet. Challenge of E. coli significantly (P < 0.01) increased the bacterial population of E. coli, coliforms, and Salmonella in cecal parts of broilers' intestines. In challenged birds receiving BMD or BS, E. coli, coliform, and Salmonella populations of ceca showed a significant (P < 0.01) reduction. Both BMD and BS increased the digestibility of nutrients significantly (P < 0.01), but a reduction was observed in E. coli challenged groups. Results of the study suggest that spore-forming probiotics are partially effective in unsuitable rearing situations such as colibacillosis in which the load of harmful bacteria is high.

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.