EN
Antimicrobial susceptibility of isolated enterotoxigenic E. coli, Salmonella enterica serovar Choleraesuis, Pasteurella multocida and Streptococcus suis from pigs was tested in the Veterinary Institute of the Lithuanian Veterinary Academy. Commensal E. coli and Enterococcus faecalis were also included in the testing as commensal bacteria. Clinical and pathological material was investigated from various regions of the country. Isolation and identification of bacteria was done using common methods. The agar diffusion method according to NCCLS guidelines was applied for antimicrobial susceptibility testing. Enterotoxigenic E. coli showed the highest resistance to tetracycline (67%), ampicillin (52%) and sulfamethoxazole-trimethoprim (43%). Not less than 90% of these bacteria were susceptible to colistin, florfenicol and ceftiofur. Salmonella Choleraesuis demonstrated the highest resistance to tetracycline (53%). Florfenicol, ceftiofur and enrofloxacin were effective against most strains of salmonella. Pasteurella multocida in most cases were susceptible to all the tested antimicrobials, however 20% of the isolates were resistant to sulfamethoxazole-trimethoprim. Streptococcus suis demonstrated the highest resistance to tetracycline (43%), lincomycin (40%), sulfamethoxazole- -trimethoprim (40%), and erythromycin (30%). Ceftiofur was the most effective against S. suis. Commensal E. coli showed less resistance than enterotoxigenic E. coli, however not less than 25% of isolates were resistant to tetracycline, sulfamethoxazole-trimethoprim and ampicillin. All the tested Enterococcus faecalis were susceptible to vancomycin and ceftiofur and 80% of enterococci were resistant to tetracycline.