Evaluation of colistin consumption in swine and poultry of Marche region during the 2017-2019 period

In Italy, the National Plan against Antimicrobial Resistance (PNCAR 2017-2020) involves both human and veterinary sectors. The last one was requested to reduce colistin consumption, a first choice antibiotic for human health. Indeed, the Plan defines specific limits to reach within 2020. In Marche region, there is a project from 2017, consisting in monitoring antibiotic consumption in livestock, with particular reference to Critically Important Antimicrobials (CIAs), like colistin. The project represents an AMR stewardship, which involves regional Veterinary Services, veterinary professionals and the IZS Umbria e Marche, developing a specific training and education path ad hoc.

In this work, we have considered data coming from swine and poultry prescriptions of Marche region in the 2017-2019 period, using these for the calculation of ADDD (Animal Defined Daily Doses), a method already used in human. In practice, we have first established DDDvet values, as suggested by ESVAC, obtained from the Italian drugs containing colistin made for the considered species.

Colistin prescription in swine reduced of 97% (from 20.60 in 2017 to 0.69 DDD/1000 animals-die in 2019). In poultry, a reduction of 69% was obtained (from 5.07 in 2017 to 1.56 DDD/1000 animals-die in 2019). Then, there was an evidence of reduction more than 70% in colistin consumption, demonstrating the importance of the education and awareness program sponsored by Competent Authorities and the other stakeholders involved. The used method of calculation (ESVAC) is different from the currently applied one, as it consists of standardized unity of measures, using prescription data rather than sales ones.

Monitoring antibiotic consumption both in human and veterinary sector is essential to understand AMR, as well is important the possibility to compare the data to each other. The present work demonstrate that, also in veterinary, is possible to apply the DDD-method to evaluate antibiotic consumption, like colistin.

Key messages

Colistin consumption has reduced in swine and poultry sectors in the 2017-2019 period. A standardized method of calculation of antibiotic consumption in animals is strongly needed.

Effect of administration of vitamin E and selenium during the dry period on mammary health and milk cell counts in dairy ewes

The effect of parenteral administration of two subcutaneous injections of vitamin E and Se (5 mg and 0.1 mg/kg of body weight, respectively) during the dry period on the mammary health and milk somatic cell counts of 25 dairy ewes was investigated. Supplementation reduced somatic cell counts (5.4 vs. 6.0 log10) during the subsequent lactation but had no effect on the incidence of clinical mastitis (4% vs. 6%) and intramammary infections (9.0% vs. 11.3%). Furthermore, the administration of vitamin E and Se was associated with differences in differential cell counts of milk samples (macrophages, 48.8% vs. 38.4%; polymorphonuclear neutrophils, 40.1% vs. 50.7%; and eosinophils, 0.7% vs. 1.4% for control ewes and ewes receiving supplements, respectively). The administration of these supplements also increased erythrocyte glutathione peroxidase activity (139.5 vs. 86.3 U/ml of packed cell volume) and the percentage of blood neutrophils that reduced nitroblue tetrazolium after bacterial extract stimulation (48.6% vs. 38.7%). Parenteral administration of vitamin E and Se to ewes during the dry period appeared to have influenced mammary gland status during the subsequent lactation and particularly total and differential milk cell counts.