Non-typhoidal Salmonella enterica subsp. enterica serovar infantis, is an important aetiological agent of salmonellosis, isolated from poultry products. Salmonella strains, resistant to a number of antimicrobials, are becoming quite common and that is an emerging problem in prophylaxis and treatment of the disease. In the present study we deal with 15 strains of S. infantis, isolated from chicks with salmonellosis, and their susceptibility to antibacterial drugs of different groups: fluoroquinolones, aminoglycosides, cephalosporins, nitrofurans, tetracyclines, sulfadimidine/trimethoprim and chloramphenicol. The antimicrobial susceptibility was evaluated by disc diffussion assay. The results were identified as follows: susceptible strain, intermediate susceptibility, resistant strain. In the process of evaluating the susceptibility of S. infantis to different antimicrobials we obtained ambiguous results. Our data show that the isolates we studied (93-100% of all the strains) were highly sensitive to aminoglycosides namely kanamycin, tobramycin, netillin and amikacin. But only 40% of the isolates were sensitive to neomycin and 79% - to gentamicin. As many as 93% of the isolates proved resistant to streptomycin. As for fluoroquinolones 87-93% of the studied isolates were sensitive to enrofloxacin and levofloxacin; 67-73% of them were sensitive to ofloxacin and ciprofloxacin. As many as 86% of the studied isolates of S. infantis were resistant to norfloxacin and moxifloxacin. As many as 79% of the isolates were resistant to cotrimoxazole and 53% of the isolates – to chloramphenicol. All of the studied strains of Salmonella proved to be resistant to tetracycline, doxycycline, furazolidone, nitrofurantoin, ceftazidime, cefotaxime.
