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Encapsulation of Streptococcus uberis: influence of storage and cultural conditions.

Authors
  • Matthews, K R1
  • Jayarao, B M
  • Guidry, A J
  • Erbe, E F
  • Wergin, W P
  • Oliver, S P
  • 1 USDA, ARS, Department of Animal Science, University of Tennessee, Knoxville 37901-1071.
Type
Published Article
Journal
Veterinary Microbiology
Publisher
Elsevier
Publication Date
Apr 01, 1994
Volume
39
Issue
3-4
Pages
361–367
Identifiers
PMID: 7518989
Source
Medline
License
Unknown

Abstract

Streptococcus uberis (n = 100) isolated from bovine mammary secretions were assessed by India ink for expression of capsule. Organisms were evaluated under four conditions; (1) after primary culture on blood agar, (2) following 5 passages on blood agar, (3) after 5 passages in Trypticase Soy Broth (TSB), and (4) after storage in 10% skim milk. Strains from primary culture (44 of 100) were positive for an unstained halo (capsule) by the India ink method. Number of strains expressing capsule decreased greatly after passage and following storage. Freeze-etching followed by electron microscopy confirmed results of India ink preparations. Strains were also cultured in various media to determine influence of medium components on capsule expression. Todd-Hewitt medium supplemented with either serum or egg yolk enhanced the size of capsule expressed. Results of this study may aid researchers investigating the pathogenicity of S. uberis.

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