Colistin is an antibiotic commonly used to treat illnesses caused by the bacteria Escherichia coli (E. coli). This is particularly the case for colibacillosis in piglets. This disease, common after weaning, causes diarrhoea. Problem: the significant use of colistin can lead to the appearance of resistant bacteria. One of the solutions explored to use less colistin is its association with alginate nanoparticles, a polysaccharide. The antibiotic is thus incorporated into these particles of nanometric size.
Less risk of antibiotic resistance
In the project context Sincolistin (Strategic alternatives to reduce the use of colistin in pig farming practices), funded by the National Research Agency, the effectiveness of nanoparticles was tested on batches of eight piglets presenting with diarrhea or hyperthermia following an infection with E. coli. After the start of the treatment, none of the 96 faecal samples taken from the pigs treated with the nanoparticles revealed any sign of diarrhoea. In comparison, diarrheal symptoms were observed in three of the samples taken from the piglets treated with colistin administered in the conventional manner and nine from the untreated group. It can therefore be concluded that the colistin-alginate nanoparticle formulation is at least as effective as conventional treatment, while using a lower dose of colistin. Moreover, a few days after the treatment, the population ofE. coli feces was mostly non-resistant to colistin.
« As the formulation of colistin with alginate nanoparticles requires less colistin than the conventional treatment, there is fewer antibiotics released into the environment following treatment and therefore less risk of bacteria developing resistance. concludes Isabelle Kempf, Head of the Mycoplasmology Bacteriology and Antimicrobial Resistance Unit at ANSES’s Ploufragan-Plouzané-Niort laboratory. His unit conducted the study on piglets in collaboration with the laboratory’s Cleaned Pig Production and Experimentation Department. The study was published in the journal Veterinary Microbiology last March. Further studies are now needed to confirm, under various experimental or field conditions, the therapeutic efficacy and safety of colistin-loaded alginate nanoparticles against post-weaning diarrhea in piglets.