Strain typing among enterococci isolated from home-made Pecorino Sardo cheese

Abstract

Three molecular techniques (RAPD-polymerase chain reaction analysis, plasmid profile and pulsed-field gel electrophoresis) were used for a preliminary approach to type, at strain level, enterococci isolated from a 24-h-old home-made Pecorino Sardo (protected designation of origin) cheese. A high genetic polymorphism was found. Clusters obtained by the RAPD technique and plasmid profile analysis contained different strains. Pulsed-field gel electrophoresis proved to be an efficient and highly reproducible typing method. In addition, by combining the results from plasmid profile analysis and pulsed-field gel electrophoresis, it was possible to identify closely related strains probably belonging to the same clonal lineage. z 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

Traditional and innovative production methods of Fiore Sardo cheese: a comparison of microflora with a PCR‐culture technique

“…Although enterococci are not always considered as generally recognised as safe (GRAS), they constitute part of the normal food microflora (Franz et al 1999), and play an important role in the manufacture of cheeses typical of Mediterranean countries. Our results are consistent with those reported from other authors for different ewe's milk cheeses (Ledda et al 1994;Arizcun et al 1997;Franz et al 1999Franz et al , 2003Mannu et al 1999;Gomez et al 2000;Prodromou et al 2001;Mannu and Paba 2002;Foulqui e Moreno et al 2006;Pisano et al 2007;Ogier and Serror 2008).…”

Genotypic and technological diversity of Leuconostoc mesenteroides and Lactobacillus paracasei subsp. paracasei strains for use as adjunct starter cultures in Pecorino di Filiano cheese

“…For screening of strains of each species, one hundred nanograms of the DNA was submitted to RAPD analysis using primer M13 (5′-GAGGGTGGC GGTTCT-3′) as previously described by Bonomo et al (2008). PCR amplification was carried out in a Genius Techne Progene thermal cycler (Cambridge, UK) using the following programme described by Mannu et al (1999): initial denaturation at 90°C for 10 min; 40 cycles of denaturation at 94°C for 1 min, annealing at 45°C for 20 s and extension at 72°C for 54 s; ending with a final extension at 72°C for 2 min. The PCR products were separated by electrophoresis on 2% (w/v) agarose gels at 100 V for 4 h. Gels were stained with 0.5 lg/mL ethidium bromide (Serva) for 30 min.…”

Transcriptional analysis of virulence-related genes in enterococci from distinct origins

“…Although a concern as human pathogens, these bacteria also play a beneficial role in the development of sensory characteristics of fermented foods, such as traditional cheeses produced in Mediterranean countries (Tsakalidou et al 1993;Desmasures et al 1997;Mannu et al 1999;Andrighetto et al 2001). In Portugal, enterococci represent the predominant lactic acid bacteria present in several artisanal cheeses produced from raw ewe's milk (Lopes et al 1999).…”