| Abstrakt: |
A retrospective study of 256 cases of naturally acquired Streptococcus suisinfections in swine submitted to the Indiana Animal Disease Diagnostic Laboratory from 1985 to 1989 was performed to determine the epidemiologic factors and antibiotic susceptibility patterns associated with S. suisserotypes 1–8 and 1/2. A standardized computer form was used to record the history, signalment, and clinical signs obtained from the records of selected cases and the microscopic lesions identified after review of the histopathology slides for each case. A computer statistics package (SAP) was used to evaluate the data. Although the number of recovered S. suisisolates increased in the fall and winter months, most serotypes were readily isolated throughout the year; only serotypes 1, 4, 7, and 1/2 increased in frequency of isolation in the fall, winter, and spring months. The majority (6 1.1%) of infected pigs in this study were < 12 weeks of age. More than 75% of pigs infected with serotypes 1, 6, 7, and 1/2 were < 12 weeks of age. There was extensive overlap in the age distributions for pigs with each serotype, and statistically significant differences for most serotypes were not observed. Fifty percent of pigs infected with S. suisserotypes 1 and 1/2 were 3–10 weeks of age, 50% of pigs infected with serotype 2 were 6–14 weeks of age, and 50% of pigs infected with serotypes 3, 4, 5, 7, and 8 were 2–16 weeks of age. Isolates of S. suiswere not uniformly susceptible to penicillin, and a large percentage of isolates were resistant to many antibiotics in common usage. The results of this study indicated that the various serotypes of S. suiscould not be readily separated based on antibiograms, epidemiologic factors (herd size, breed, etc.), or geographic location. |
