The present work is a continuation of our translational research focusing on the use of silver nanoparticles (AgNPs) to solve the global problem of antibiotic resistance. In vivo fieldwork was done with 300 breeding farm cows with serous mastitis. Ex vivo assays revealed that after cow treatment with the antibiotic drug Spectromast LCTM, S.dysgalactiae susceptibility to 31 antibiotics dropped by 22.9%, but after treatment with Argovit–CTM AgNPs, it was raised by 13.1%. This was explained by the fact that the percentage of isolates with an efflux effect after Spectromast LC treatment resulted in an 8% increase, while Argovit-C-treatment caused a 19% decrease. The similarity of these results to our previous results on S. aureus isolates from mastitis cows treated with the antibiotic drug Lactobay and Argovit–CTM AgNPs was shown. So, mastitis treatments with Argovit-CTM AgNPs can partially return the activity of antibiotics towards S.dysgalactiae and S. aureus, while, in contrast, treatments with antibiotic drugs such as Spectromast LC and Lactobay enhance bacterial resistance to antibiotics. The results of this work strengthen the hope that in the future the use of AgNPs as efflux pump inhibitors will recover the activity of antibiotics, and thus will preserve the wide spectrum of antibiotics on the market.

The current work is a continuation of our studies focused on the application of nanoparticles of metallic silver (AgNPs) to address the global problem of antibiotic resistance. In vivo, fieldwork was carried out with 200 breeding cows with serous mastitis. Ex vivo analyses showed that after the cow was treated with an antibiotic-containing drug DienomastTM, E. coli sensibility to 31 antibiotics decreased by 27.3%, but after treatment with AgNPs, it increased by 21.2%. This could be explained by the 8.9% increase in the portion of isolates showing an efflux effect after DienomastTM treatment, while treatment with Argovit-CTM resulted in a 16.0% drop. We verified the likeness of these results with our previous ones on S. aureus and Str. dysgalactiae isolates from mastitis cows processed with antibiotic-containing medicines and Argovit-CTM AgNPs. The obtained results contribute to the recent struggle to restore the efficiency of antibiotics and to preserve the wide range of antibiotics on the world market.

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Salmonelloses, which are associated with products from clinically healthy animals that undergone veterinary and sanitary observations and examinations and are secondary-contaminated in the process, transportation, processing and marketing, are at the forefront of the list of emerging food zoonoses. The haphazard use of antibiotics in agriculture contributes to the selection of resistant clones of microorganisms. The high resistance of strains of salmonella isolated from poultry production poses a real risk of transmission through the food chain to humans, as well as being perpetuated and passed on to subsequent generations of bacteria, expanding geographical areas as a result of globalization. Separation of Salmonella microorganisms from poultry production was carried out in accordance with GOST 31468-2012, antigenic profile of isolated isolates was determined according to the classification of Kaufmann-White, sensitivity of microorganisms to antibacterial preparations - according to MUK 4.2.1890-04. In the study of 503 samples of poultry production 42 isolates of microorganisms of the genus Salmonella were isolated, which amounted to 8.35% of the number of samples studied. Sensitivity to antimicrobial agents showed that 42% of the isolates were resistant to tetracyclines and only 5-16% were resistant to antibiotics of the II generation of fluoroquinolones (ciprofloxacin, norfloxacin) and III generation of cephalosporins (cefotaxime, cefoxitin, ceftriaxone). The authors found out the change in resistance towards cephepium, ciprofloxacin and amoxicillin resistance in the secondary isolates of S. virhow. The study of biological properties, frequency of isolation and resistance to various AMF of Salmonella microorganisms is an integral part of the development of mechanisms for controlling the formation of resistance to antimicrobial agents.

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