Diagnostical availability of the hemolytically active exosubstance of Corynebacterium pseudotuberculosis for isolation and identification of Streptococcus agalactiae and its comparison with the beta-toxin of Staphylococcus aureus

Abstract

Summary In blood agars containing erythrocytes from ruminants, hemolysis due to Streptococcus agalactiae, and streptococci of group B, is enhanced by the hemolytically active exosubstance of Corynebacterium pseudotuberculosis. The effect is displayed by both native and prepurified exosubstance. Unlike staphylococcal beta‐toxin, corynebacterial exosubstance does not enhance hemolytic activity of Streptococcus uberis strains, not even of the CAMP‐positive ones. The corynebacterial exosubstance, denoted by the authors as COREX, is of use for rapid identifcation of Streptococcus agalactiae and its differentiation from Streptococcus uberis. It is usable in tests with pure cultures as well as added to the substrate for identification of Streptococcus agalactiae in primary culture. Zusammenfassung Die Verwendbarkeit der hämolytisch aktiven “Exosubstanz” von Corynebacterium pseudotuberculosis bei der Isolierung und Bestimmung von Streptococcus agalactiae und ihr Vergleich mit dem beta‐Toxin von Staphylococcus aureus Auf Blutagar‐Nährböden, die Erythrozyten von Wiederkäuern enthalten, wird die von Streptococcus agalactiae, bzw. von Streptokokken der Gruppe B verursachte Hämolyse durch die hämolytisch aktive “Exosubstanz” von Corynebacterium pseudotuberculosis potenziert. Diese Fähigkeit besitzt die “Exosubstanz” in nativer und in vorgereinigter Form. Zum Unterschied vom Staphylokokken‐Beta‐Toxin verstärkt die “Exosubstanz” nicht die hämolytische Aktivität der Streptococcus uberis‐Stämme, auch nicht die der CAMP‐positiven. Die “Exosubstanz”, von den Verfassern als COREX bezeichnet, ist für die schnelle Diagnostik von Streptococcus agalactiae, vor allem im Hinblick auf seine Unterscheidung von Streptococcus uberis, geeignet. COREX ist auch als Zusatz zum Nährboden, für die Bestimmung von Streptococcus agalactiae in Primokulturen, verwendbar. Résumé Valeur diagnostique de l'exosubstance hémolytique du Corynebacterium pseudotuberculosis pour l'isolation et l'identification du Streptococcus agalactiae et sa comparaison avec la beta‐toxine du Staphylococccus aureus Au agar du sang, contenant des érythrocytes des ruminants, l'hémolyse produit par Streptococcus agalactiae et par streptococci de la groupe B est renforcée par l'activité hémolytique de l'exosubstance du Corynebacterium pseudotuberculosis. Cet effet est exercé egalement par l'exosubstance corynebacterielle native et prepurifié. Contrairement à la beta‐toxine du Staphylococcus, elle ne renforce pas l'activité hémolytique des souches du Streptococcus uberis, même de celles qui sont CAMP‐positives. L'exosubstance corynébacterielle, désignée par les auteurs comme COREX, est apte à la diagnose rapide du Streptococcus agalactiae et son differencement du Streptococcus uberis. COREX est applicable en essais avec cultures pures et aussi pour supplémenter le agar à déterminer Streptococcus agalactiae en culture primaire. Resumen Valor diagnóstico de la exosubstancia hemolíticamente activa producida por Corynebacterium pseudotuberculosis y comparación de ésta con la beta‐toxina...

Bovine Mastitis Caused By Streptococcus uberis: Virulence Factors and Biofilm

“…Skalka and Smola (1981) reported a lethal effect of this factor when was administered parenterally in mice and rabbit and the active substance showed a similar effect like the CAMP factor of S. agalactiae [73]. Different studies have shown that not all S. uberis tested strains have a positive CAMP reaction although it could be a virulence factor [13,74,75].…”

Differentiation of toxigenic Staphylococcus aureus strains isolated from retail meat products

“…Crystal violet agar was used for phenotypic differentiation of S. aureus isolates based on the type of growth as a possible indicator of the strains origin ( Table 2). The type of growth (colour of colonies) was maeked with the following letters: A (yellow), C (blue-violet), and E (white) (Skalka & Smola 1981).…”

“…The phenotypic method used was the assessment of the growth on crystal violet agar (CV agar) (Skalka & Smola 1981). A PCR-based genotypic method served for screening the isolates for the sak gene encoding the enzyme staphylokinase typically found in human S. aureus isolates (Sung et al 2008).…”