Genotypic and phenotypic heterogeneity in Enterococcus isolates from Batzos, a raw goat milk cheese.
This study investigated the genotypic and phenotypic diversity in 34 isolates of enterococci obtained during ripening of Batzos cheese from raw goat milk and characterized phenotypically as Enterococcus durans. RAPD-PCR, plasmid profiling and PFGE were used to study the genetic variability and distinguish closely related isolates. Species recognition by means of RAPD-PCR was in agreement with the phenotypic identification for 29 strains. One strain was characterized as Lactococcus lactis subsp. lactis by RAPD-PCR and four strains were grouped with the Enterococcus faecium reference strain. All strains were vancomycin sensitive, while 10 strains showed beta-haemolytic reaction on human blood and the majority of them (88.9%) showed decarboxylase activity on tyramine. All strains exhibited antagonistic activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Listeria monocytogenes and the majority inhibited Enterococcus faecalis. Isolates displayed weak acidifying ability and low proteolytic activities when grown in milk for 24h. However, their caseinolytic activity after growth in milk for seven days was significant with preference for alphas-casein degradation.
Psoni
L
L
Laboratory of Food Microbiology and Hygiene, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Kotzamanides
C
C
Andrighetto
C
C
Lombardi
A
A
Tzanetakis
N
N
Litopoulou-Tzanetaki
E
E
D000818:Animals; D002611:Cheese / Q000382:microbiology*; D004587:Electrophoresis, Agar Gel / Q000379:methods; D016983:Enterococcus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification*; D005516:Food Microbiology; D005838:Genotype; D006041:Goats; D008892:Milk / Q000382:microbiology; D010641:Phenotype; D010802:Phylogeny; D010957:Plasmids; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods; D013045:Species Specificity; D020713:Vancomycin Resistance