돼지단독의 세균학적 연구

Bacteriological studies on swine erysipelas

The present study was conducted to investigate biochemical, serological and pathogenic characteristics of Erysipelothrix rhusiopathias isolated from the cases of acute septicemic swine erysipelas and from tonsils of apparently healthy slaughter pigs. A total of 51 cultures of E rhusiopathias was isolated from septicemic Pigs of 12 isolated outbreaks of acute swine erysipelas in Youngnam province during the period from June 1988 to September 1991 and 26 cultures(11.1%) were recovered from tonsils of 234 apparently healthy slaughter pigs from February 1991 to September 1991. The majority of biochemical and cultural properties of 77 isolates were identical to those of reference strains employed and there were no differences in the properties between the strains recovered from septicemic erysipelas and those from healthy pigs. All of the 51 isolates from acute septicemic cases were serotype la, while 26 isolates from tonsils of healthy slaughter pigs were spreaded into 7 serotypes, i.e. serotype la(6 strains), serotype 1b(2 strains), serotype 2(4 strains), serotype 12(1 strain), serotype 17(2 strains), serotype 21(1 strain) and the remains 3 cultures were untypable. All isolates were highly susceptible(MIC range : 0.025-0.78iu or ㎍/ml) to ampicillin, cephalothin, erythromycin, lincomycin and penicillin G, and moderately susceptible(MIC range : 0.78-25 ㎍/ml)to chloramphenicol, oleandomycin and oxytetracycline, although they were highly resistant(MIC range : ＞400㎍/ml) to kanamycin and sulfadimethoxine. Fifty three(68.8%) strains of the isolates were susceptible to dihydrostreptomycin while the remaining 23 cultures(31.2%) were resistant to the drug. All of the 4 cultures each from septicemic cases and from tonsils of healthy pigs were pathogenic for mice and LD₅₀ was 6.6×10-3.0×10² cfu and 3.9×10²-4.6×10³ cfu, respectively. Mice immunized subcutaneously with live vaccine survived after challenge to virulent isolates of E rhusiopathiae.