Drug Susceptibility of Haemophilus pleuropneumoniae Strains Isolated from Pigs

Abstract

Haemophilus pleuropneumoniae strains isolated from pigs during the period from 1974 to 1982 were serotyped and examined for their susceptibility to 21 antimicrobial drugs. Of 109 field isolates in Japan and surrounding countries (Japan; 105, Korea; 2, Taiwan; 2), 105 strains were of serovar 2, two were of serovar 3, and the remaining two were of serovar 5. The great majority of the field isolates, 107 strains, were highly susceptible to penicillins, chloramphenicol, tetracyclines, rifampicin, trimethoprim and furazolidon. These strains were also susceptible to cephalexin and colistin. However, susceptibilities to aminoglycosides, macrolides, sulfamonomethoxine and nalidixic acid were not so high. The ramaining two strains were found to be drug-resistant; strain Hp1 was resistant to penicillin, tetracycline, streptomycin and sulfonamide, and strain 966 was resistant to streptomycin and sulfonamide. The former was identified as serovar 3 and the latter was serovar 5. All the 105 strains of serovar 2 were durg-sensitive, and no increase in the resistance of this organism had been observed during the period from 1974 to 1982.