EN
The aim of the study was to analyse the antibiotic sensitivity of bacteria isolated from nasal mucosa of foals and young horses with upper respiratory tract infections. Included in the study were one hundred forty nine bacterial strains belonging to ten species: Staphylococcus aureus (4), Staphylococcus intermedius (4), Streptococcus equi subsp. zooepidemicus (12), Bordetella bronchiseptica (15), Klebsiella pneumoniae pneumoniae (1), Moraxella sp. (4), Pasteurella pneumotropica (2), Staphylococcus lentus (16), Staphylococcus sciuri (48), Staphylococcus xylosus (43). Antibiotic sensitivity tests were performed by the use of the disc diffusion method on Mueller-Hinton agar, according to NCCLS recommendations. Twenty six chemotherapeutics were used to assess antibiotic sensitivity profiles of: amoxicillin (AMX), amoxicillin with clavulic acid (AMC), ampicillin (AM), carbenicillin (CB), cefotaxim (CFM), cefuroxim (CXM), cefalexin (CN), chloramphenicol (C), erythromycin (E), flumequine (AR), gentamicin (GM), kanamycin (K), linkomycin (L), minocycline (MI), neomycin (N), nitrofurantoin (FM), norfloxacine (NOR), oksacillin (OX), penicillin G (P), rifampicin (RI), spiramycine (SP), streptomycin (S), sulphonamides (G), sulphonamides and trimethoprim (SXT), tetracycline (TE), vankomycine (VA). Results obtained during the study indicated the highest effectiveness of amoxicillin with clavulic acid (AMC), cephalosporines, gentamicin (GM), minocycline (MI), rifampicin (RI) and sulphonamides combined with trimethoprim (SXT) against the bacterial strains examined. The percentage of strains susceptible for AMC was 70.4%, cefalexin - 58.6%, cefotaxim - 62.1%, cefuroxim - 65.1%, GM - 61.3%, MI - 58.7%, RI - 67% and SXT - 58.4%. The highest (100%) resistance against chemotherapeutics examined in the study was demonstrated by the Klebsiella pneumoniae pneumoniae strain, isolated from suppurative lung lesions from a 2-month-old foal, showing pronounced respiratory signs antemortem and pneumonia lesions upon death.