SEROLOGICAL CHARACTERIZATION AND ANTIMICROBIAL SUSCEPTIBILITY OF ACTINOBACILLUS-PLEUROPNEUMONIAE STRAINS ISOLATED FROM PIGS IN SPAIN

Seventy-one isolates of Actinobacillus pleuropneumoniae isolated from the lungs of pigs in outbreaks of pleuropneumonia in Spain were seroty ped by indirect haemagglutination. Serotype 4 (42.2 per cent), serotyp e 7 (22.5 per cent) and serotype 2 (12.8 per cent) were predominant, w hereas serotypes 1, 3, 6, 8, 9, 12 and untypable isolates were present only in small numbers. Serotypes 1, 2, 4 and 7 originated mainly from cases of acute pleuropneumonia, whereas serotypes 3, 6, 8, 9 and 12 w ere associated with chronically infected herds. The susceptibility of the isolates to 20 antimicrobial agents was determined by agar disc di ffusion. Most were susceptible to cefuroxime, cefaclor, cefazolin, kan amycin, tobramycin, gentamicin, oxolinic acid, ciprofloxacin, enoxacin , thiamphenicol, colistin and trimethoprim/sulphamethoxazole. Marked r esistance was found with amoxicillin, ticarcillin, oxytetracycline, do xycycline and metronidazole.