Zum Vorkommen von koagulasepositiven Staphylokokken in Hackfleisch: Lysisspektrum, biochemische Eigenschaften und Enterotoxinbildung*

Zusammenfassung Aus 168 Hackfleischproben wurden unter Verwendung von Selektivnahrmedien eigelbpositive Staphylokokken isoliert. 20 Proben enthielten Staphylokokkenzahlen von mehr als 103/g. Die isolierten Stamme zeigten, abgesehen von einer hoheren Antibiotikaempfindlichkeit, im biochemischen Verhalten und im Lysisspektrum keine wesentlichen Abweichungen gegenuber vergleichsweise untersuchten Krankenhausstammen. Unter 104 ausgewahlten Hackfleischstammen wurde 20mal Enterotoxinbildung nachgewiesen. Summary Contribution to the occurrence of coagulase-positive Staphylococci in ground meat and attempts to detect enterotoxins 168 retail samples of ground meat (beef and pork) were tested for the presence of egg yolk positive staphylococci using two selective media, the tellurite-polymyxin-egg-yolk (TPEY)-agar and the potassium thiocyanate-actidione-sodium-azide-egg-yolk-pyruvate (KRANEP)-agar. The samples tested contained 70.8% strains which were egg yolk positive on TPEY and 48.2% on KRANEP, respectively. Of these 66.8% (TPEY) and 92.1% (KRANEP) were coagulase-positive. The prevailing part of the samples showed numbers of staphylococci up to 500/Gr. 20 samples contained more than 1000 staphylococci/Gr. The biochemical behaviour and the phage pattern of the strains originating from ground meat were compared with those of 184 hospital strains. The ground meat strains were shown to be more sensitive to antibiotics. With regard to the other criteria tested no significant differences were found between the majority of the ground meat staphylococci and the strains originating from human patients. Within a small group of 104 selected ground meat strains 20 proved to be positive for enterotoxin; 8 strains were positive for A, 1 for B, and 11 for C. Compared with these findings, enterotoxin production among the hospital strains could be detected in a twofold higher incidence. Resume Sur la presence de staphylocoques coagulase-positifs dans la viande hâchee et essais de mise en evidence des enterotoxines On isole des staphylocoques vitellus-positifs a partir de 168 echantillons de viande hâchee, en utilisant des milieux selectifs. Dans 20 des echantillons, on trouve un nombre de staphylocoques depassant 103/g. Par rapport a des souches d'hopital examinees a titre comparatif, les souches isolees ne manifestent pas de differences notables dans leur comportent biochimique et leur spectre de lyse, exception faite d'une sensibilite plus elevee aux antibiotiques. Sur 104 souches provenant d'echantillons selectionnes de viande hâchee, on met en evidence a 20 reprises la formation d'enterotoxines. Resumen La presencia de estafilococos coagulasa-positivos en la carne picada y ensayos para identificar sus enterotoxinas De 168 muestras de carne picada se aislaron estafilococos yema de huevo-positivos, utilizando medios nutritivos selectivos. 20 muestras contenian cantidades de estafilococos superiores a 103/g. Las estirpes aisladas no presentaban, prescindiendo de la sensibilidad mayor frente a los antibioticos, divergencias esenciales en el comportamiento bioquimico y en el espectro litico frente a las cepas de sanatorios examinadas de forma comparativa. Entre 104 estirpes seleccionades de carne picada, se identifico 20 veces la produccion entreotoxinica.