Polymerase chain reaction detection of enterotoxins genes in coagulase-negative staphylococci isolated from Brazilian Minas cheese.
For a long time, Staphylococcus aureus has been always thought to be the only pathogenic species among Staphylococcus, while coagulase-negative staphylococci (CNS) were classified as contaminant agents. However, molecular techniques have shown that these microorganisms also possess enterotoxin-encoding genes. The aim of this study was to analyze the frequency of genes for staphylococcal enterotoxins SEA, SEB, SEC, and SED in CNS strains isolated from Minas soft cheese and to assess the in vitro production of toxins. CNS were found in 65 (72.2%) samples of cheese: 23 were Staphylococcus saprophyticus, 16 Staphylococcus warneri, 10 Staphylococcus epidermidis, 9 Staphylococcus xylosus, 3 Staphylococcus haemolyticus, 2 Staphylococcus schleiferi subsp. schleiferi, and 1 each Staphylococcus capitis subsp. urealyticus and Staphylococcus caprae. Seventeen (26.2%) CNS strains had genes for enterotoxins, and sea was more frequently found (18.5%), followed by sec in three and seb in two strains, whereas the sed gene was not found. S. saprophyticus showed enterotoxin genes in 6 of 23 isolates, but only sea was observed. On the other hand, five strains of S. warneri showed the sea, seb, or sec gene. In spite of the presence of these enterotoxin genes, these strains did not produce enterotoxins in vitro. It is essential to understand the real role of CNS in food, and based on the presence of enterotoxin genes, CNS should not be ignored in epidemiological investigations of foodborne outbreaks.
Rall
Vera Lúcia Mores
VL
Department of Microbiology and Immunology, Institute of Biosciences, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil. vlmores@ibb.unesp.br
Sforcin
José Maurício
JM
de Deus
Maria Fernanda Ramos
MF
de Sousa
Daniel Casaes
DC
Camargo
Carlos Henrique
CH
Godinho
Natália Cristina
NC
Galindo
Luciane Almeida
LA
Soares
Taíssa Cook Siqueira
TC
Araújo
João Pessoa
JP
D001938:Brazil; D002611:Cheese / Q000382:microbiology*; D003030:Coagulase / Q000032:analysis*; D004269:DNA, Bacterial / Q000032:analysis; D004768:Enterotoxins / Q000096:biosynthesis / Q000235:genetics*; D005516:Food Microbiology; D016133:Polymerase Chain Reaction; D013210:Staphylococcus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
D003030:Coagulase; D004269:DNA, Bacterial; D004768:Enterotoxins