Principles of antimicrobial therapy

Contagious and infectious diseases in animals must be prevented, above all, by ensuring good production conditions. However, on occasion, the use of antimicrobials is necessary. On such occasions, antimicrobial treatment must be based on legislation and the following principles:

  • The use of antimicrobials must be well justified
  • Whenever antimicrobials are used in animals, they also affect human health. This applies to both production and companion animals
  • Metaphylactic antimicrobial medication must only be used when a veterinarian deems such treatment necessary on account of the severity of the case or the disease situation at the animal unit. The use of metaphylactic antimicrobial medication must always be based on veterinary grounds
  • If other treatments found to be equally effective as antimicrobial treatment are available, they must be given precedence over all other treatments
  • The course of antimicrobial treatment must not be longer than is required to cure the disease
  • Before commencing antimicrobial treatment, the veterinarian must establish, on the basis of either a clinical or a microbiological investigation that the signs of the disease indicate a bacterial infection
  • If necessary, the veterinarian shall take representative samples in order to define the causative microbe and its susceptibility to antimicrobials
  • In selecting antimicrobial, information on the patient, the cause of the infection and disease and any available medication must be taken into account. The selected antimicrobial and dosage are chosen so that the microbes are either killed or their growth rate is decreased, in order to enable the body to destroy the microbe and recover from the disease
  • Primarily, a narrow spectrum antimicrobial medicine must be used. The use of broad-spectrum antimicrobials and antimicrobial combinations should be avoided. If the pathogen is susceptible to penicillin, the illness must not be treated with other beta-lactams or broad-spectrum antimicrobials unless the patient is allergic to penicillin
  • Regarding salmonella infections, antimicrobials are only used if the case involves a systemic infection which threatens the animal’s life. Antimicrobials must not be used in the prevention, eradication or treatment of salmonella infections in poultry, cattle or pigs.
  • In the case of viral diseases, antimicrobials should not be used to prevent secondary bacterial infections.
  • In the case of repeated courses of antimicrobials due to same disease problem the problem should be solved by improving the management and conditions.
  • When treating food-producing animals the cost of treatment and withdrawal periods need to be taken into account.
  • Antimicrobials, against which the resistance develops quickly, should be avoided.
  • The use of certain antimicrobials is prohibited or restricted in the treatment of animals in the legislation. These include avoparcine, vancomycin and teikoplatine, virginiamycin, 3th and 4th genereation cephalosporins etc.