자돈에서의 연쇄구균성 감염증에 관한 연구 II. 정상돈에서의 streptococcus suis type II에 의한 감염실태와 약제감수성

Studies on streptococcal infection in young pigs II. Prevalalce of streptococcus suis type II in clinically healthy pig and antibiotics susceptibility test of the isolates

Investigation into the bacteriology and epidemiological features of Streptococcus suis type Ⅱ infections, in particular, in clinically healthy pigs were carried out from April 1990 to April 1992 at 7 intensive pig farms of Chungnam and Kyounggi areas. Also determined were isolated frequency of streptococci in various sources of effected Pigs and antibiotics susceptibilties of the isolates. The results obtained were summarized as follows : 1. Streptococci isolated from various sample of clinically healthy pigs belonged to 190 strains of nasal discharge, 8 of brains, 2 of bloods, and 1 strain each from lung, cardiac fluid, salivary gland and small intestine. 2. Out of 204 hemolytic streptococci, 55 isolates of them (27.0%) were Str. suis type Ⅱ. 3. Prevalance of Str. suis type Ⅱ in five to seven week-old pigs were higher than them of eight week above and four week less. 4. In regional distribution of 55 Str. suis type Ⅱ, the isolating rates of Cheonan and Asan area were higher than that of Gongju and Pyongtak. 5. Among 204 hemolytic streptococci, 61 isolates of them (29.9%) were Lancefield serogroup D, 46 (22.5%) were serogroup C and 22 (10.8%) were serogroup E, the remaining 75 isolates (36.8%) were ungrouping, respectively. In additional results of serogroup D isolates by biological and serological examination, 55 were identified to Str. suis type Ⅱ and 6 were to Str. suis type Ⅰ. 6. Most strains of 133 streptococci were susceptible to ampicillin (93.2%), chloramphenicol (92.5%) and cephalothin (90.2%) while they were resistant to erythromycin (78.2%) and streptomycin (73.3%). These resuts were similar to each group of groupable strains.