title: Isolation and further characterization of phase variants of Streptococcus equi subsp. zooepidemicus.
abstract: In the present study the soft agar technique was used to isolate phase variants of S. equi subsp. zooepidemicus-cultures isolated from infections of horses. The phase variants were characterized by a compact or diffuse colony morphology in this media. The variants could be cultivated separately and further characterized genotypically by RAPD analysis and by macrorestriction analysis of their chromosomal DNA by pulsed-field gel electrophoresis, indicating the identity of both strains of each pair. The diffuse colony variants grew uniformly turbid after cultivation in fluid media, did not haemagglutinate rabbit erythrocytes, and displayed a reduced surface hydrophobicity in hexadecane and phenyl-sepharose adherence tests. The compact colony variants generally grew as sediment with clear supernatant in fluid media, haemagglutinated rabbit erythrocytes and showed an enhanced surface hydrophobicity in both hydrophobicity tests. The presented soft agar technique allowed a demonstration of phase variation of S. equi subsp. zooepidemicus and a subsequent isolation of the variants. This might be an important prerequisite to understanding the pathogenic importance of phase variation among isolates of this bacterial species.
authors.affiliation: Institut für Tierärztliche Nahrungsmittelkunde, Bakteriologie and Hygiene der Milch, der Justus-Liebig-Universität Giessen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Abdulmawjood
authors.forename: C
authors.initials: C
authors.lastname: Lämmler
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000737:chemistry; D004262:DNA Restriction Enzymes / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry; D004587:Electrophoresis, Agar Gel / Q000662:veterinary; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D005260:Female; D014644:Genetic Variation / Q000235:genetics* / Q000502:physiology; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D016133:Polymerase Chain Reaction / Q000662:veterinary; D019105:Random Amplified Polymorphic DNA Technique / Q000662:veterinary; D012141:Respiratory Tract Infections / Q000382:microbiology / Q000662:veterinary; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D013499:Surface Properties; D014591:Uterine Diseases / Q000382:microbiology / Q000662:veterinary
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes