Aims: To ascertain the identi®cation and typing of the Gram-positive, coagulase-negative cocci present in `Salsiccia Sotto Sugna', an Italian artisanal sausage. Methods and Results: Fifty-one strains were isolated and genotypically identi®ed by ampli®cation of the 16S±23S rDNA intergenic region with universal primers. Most isolates were identi®ed as Staphylococcus xylosus and one strain as Staph. condimenti. Isolates were clustered by numerical analysis of both RAPD (Random Ampli®ed Polymorphic DNA) PCR pro®les and physiological characters. Genotypic clustering allowed the separation of strains showing nitrate reduction and amino acid decarboxylase activities. Phenotypic clustering distinguished strains isolated at diverse ripening stages. Conclusions: The predominance of Staph. xylosus in Italian dry sausages was con®rmed. Genotypic similarities related to the possession of single phenotypic traits. Signi®cance and Impact of the Study: In this study, a rapid method of Staphylococcus and Kocuria species distinction was proposed. The suitability of RAPD PCR to discriminate strains of Staph. xylosus with technologically relevant activities was reported.
Identification by 16S-23S rDNA intergenic region amplification, genotypic and phenotypic clustering of Staphylococcus xylosus strains from dry sausages
TOFALO, ROSANNA;SUZZI, Giovanna
2001
Abstract
Aims: To ascertain the identi®cation and typing of the Gram-positive, coagulase-negative cocci present in `Salsiccia Sotto Sugna', an Italian artisanal sausage. Methods and Results: Fifty-one strains were isolated and genotypically identi®ed by ampli®cation of the 16S±23S rDNA intergenic region with universal primers. Most isolates were identi®ed as Staphylococcus xylosus and one strain as Staph. condimenti. Isolates were clustered by numerical analysis of both RAPD (Random Ampli®ed Polymorphic DNA) PCR pro®les and physiological characters. Genotypic clustering allowed the separation of strains showing nitrate reduction and amino acid decarboxylase activities. Phenotypic clustering distinguished strains isolated at diverse ripening stages. Conclusions: The predominance of Staph. xylosus in Italian dry sausages was con®rmed. Genotypic similarities related to the possession of single phenotypic traits. Signi®cance and Impact of the Study: In this study, a rapid method of Staphylococcus and Kocuria species distinction was proposed. The suitability of RAPD PCR to discriminate strains of Staph. xylosus with technologically relevant activities was reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
