Antimicrobial susceptibility of 181 (107 ail-harboring isolates and 74 non-
ail-harboring) Yersinia enterocolitica isolates obtained from the oral cavi
ty of swine was determined against 24 antimicrobial agents. All Y. enteroco
litica isolates were susceptible to sulfamethoxazole/trimethoprim, enroflox
acin, aminoglycosides, and nitrofurantoin. Susceptibility to tetracycline a
ppeared to vary by lot of origin. Isolates were resistant to sulfonamides (
other than sulfamethoxazole/trimethoprim), penicillin, ampicillin, ticarcil
lin, cephalothin, macrolides, and tiamulin.