title: Enterotoxin-encoding genes in Staphylococcus spp. from bulk goat milk.
abstract: Although Staphylococcus aureus has been implicated as the main Staphylococcus species causing human food poisoning, recent studies have shown that coagulase-negative Staphylococcus could also harbor enterotoxin-encoding genes. Such organisms are often present in goat milk and are the most important mastitis-causing agents. Therefore, this study aimed to investigate the occurrence of enterotoxin-encoding genes among coagulase-positive (CoPS) and coagulase-negative (CoNS) staphylococci isolated from raw goat milk produced in the semi-arid region of Paraiba, the most important region for goat milk production in Brazil. Enterotoxin-encoding genes were screened in 74 staphylococci isolates (30 CoPS and 44 CoNS) by polymerase chain reaction targeting the genes sea, seb, sec, sed, see, seg, seh, and sei. Enterotoxin-encoding genes were found in nine (12.2%) isolates, and four different genes (sea, sec, seg, and sei) were identified amongst the isolates. The most frequent genes were seg and sei, which were often found simultaneously in 44.5% of the isolates. The gene sec was the most frequent among the classical genes, and sea was found only in one isolate. All CoPS isolates (n=7) harboring enterotoxigenic genes were identified as S. aureus. The two coagulase-negative isolates were S. haemolyticus and S. hominis subsp. hominis and they harbored sei and sec genes, respectively. A higher frequency of enterotoxin-encoding genes was observed amongst CoPS (23.3%) than CoNS (4.5%) isolates (p<0.05), reinforcing the importance of S. aureus as a potential foodborne agent. However, the potential risk posed by CoNS in goat milk should not be ignored because it has a higher occurrence in goat milk and enterotoxin-encoding genes were detected in some isolates.
authors: Federal Institution for Education, Science, and Technology of Alagoas (IFAL), Santana do Ipanema-AL, Brazil.
authors: Daniele G
authors: DG
authors: Lyra
authors: Francisca G C
authors: FG
authors: Sousa
authors: Maria F
authors: MF
authors: Borges
authors: Patrícia E N
authors: PE
authors: Givisiez
authors: Rita C R E
authors: RC
authors: Queiroga
authors: Evandro L
authors: EL
authors: Souza
authors: Wondwossen A
authors: WA
authors: Gebreyes
authors: Celso J B
authors: CJ
authors: Oliveira
mesh_terms: D000818:Animals; D001938:Brazil; D003030:Coagulase / Q000032:analysis; D004269:DNA, Bacterial / Q000302:isolation & purification*; D004768:Enterotoxins / Q000235:genetics* / Q000302:isolation & purification; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005798:Genes, Bacterial; D006041:Goats; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013210:Staphylococcus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D003030:Coagulase; D004269:DNA, Bacterial; D004768:Enterotoxins