Detecção de genes do cluster egc em Staphylococcus aureus isolados de alimentos de origem animal

Zocche, Fernando; Bastos, Caroline Peixoto; Silva, Wladimir Padilha da

doi:10.1590/s0103-84782010000500021

Cited by 2 publications

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“…Os sintomas das intoxicações estafilocócicas aparecem, logo depois de um curto período de incubação quando comparados a outras intoxicações e infecções alimentares, decorrendo de 30 minutos a 8 h (3 h, em média), após a ingestão do alimento contaminado (YOUSEF & CARISTROM, 2003;HENNEKINNE et al, 2011), esse período varia com a susceptibilidade do indivíduo e a quantidade de toxina no alimento ingerido (cerca 10-20 μg /kg, num indivíduo adulto) para apresentar sintomas (EFSA, 2009;SANTANA et al, 2010;HENNEKINNE et al, 2011).…”

Section: Intoxicação Estafilocócicaunclassified

“…Sendo assim, é importante avaliar vários isolados a partir das placas de cultivo, principalmente nos casos em que sintomas típicos de intoxicação estafilocócica são observados (JØRGENSEN et al, 2005). A detecção dos genes responsáveis pela produção de enterotoxinas também se torna relevante para auxiliar no levantamento do número de casos de surtos de doenças alimentares e na análise de risco para surtos de origem alimentar (ZOCCHE et al, 2010).…”

Section: Introductionunclassified

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Fatores de virulência e subtipagem de Staphylococcus aureus isolados de laticínios orgânicos e convencionais no estado de São Paulo

Candido¹

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Foodborne illnesses are caused by ingestion of contaminated food or water. Staphylococcus aureus is able to produce enterotoxins and is one of the most common agent responsible for outbreaks of food poisoning. Intoxication is due to the ingestion of preformed enterotoxins in the food contaminated by the bacteria, which may continue viable. Among the foods involved in staphylococcal food poisoning, the cheese stands out due to the fact that S. aureus is found both in raw milk and in manipulators. The objective of this work was to isolate, identify and molecularly characterize S. aureus isolated from the processing chain of organic and conventional Minas frescal type cheese. Samples were collected from six dairies in the State of São Paulo within a radius of up to 200 kilometers from Campinas, with two collections in each dairy. The following samples were collected: raw milk, pasteurized milk, manipulators, environment (equipment, utensil, floor) and final product in order to isolate the target bacterium. Afterwards, the samples were incubated in Baird Parker Agar (BP) and the characteristic colonies were isolated with subsequent biochemical tests and polymerase chain reaction (PCR) for the identification of S. aureus. After confirmation of the species, the enterotoxin encoding genes (sea-see, seg-sej) were investigated by PCR and subtyping of spatyping, agr type and pulsed-field electrophoresis (PFGE) were performed. Thirty-eight S. aureus were identified, 18 (47.36%) of organic dairy products and 20 (52.63%) of conventional dairy products. Among the 38 isolates, 34 isolates (89.47%) presented at least one enterotoxin producing gene, with seg in 25 isolates (65.79%), sei in 18 isolates (47.37%), seb in 7 isolates (18.42%), sej in 8 (21.05%), seh in 5 (13.16%) and no sea, sec, sed and see genes were detected.The agr I gene was found in 5 isolates (13.16%), agr II in 11 (29.0%), agr III in 17 (44.74%), agr IV in 3 (7.89%); it was not possible to identify agr in 2 isolates (5.3%). A total of 14 different spa types were identified, t021 was the most frequent type (8 isolates, 21.05%), t127 was found in 5 isolates (13.16%) and t1062 in 3 isolates (7.89%). Seventeen clusters were detected based on the PFGE technique, 1 cluster with 5 isolates, 1 with 4, 2 with 3, 4 with 2 and 9 with only 1. Of the 32 profiles 4 clusters presented 2 clones with similarity of 100%. The abundance of isolates was similar between conventional and organic dairy products. The results obtained in the PFGE corroborate the identification of the main transmission points of the S. aureus strains, such as brine, utensils (lira), raw and pasteurized milk used to produce Minas frescal cheese.

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Section: Intoxicação Estafilocócicaunclassified

Section: Introductionunclassified

Fatores de virulência e subtipagem de Staphylococcus aureus isolados de laticínios orgânicos e convencionais no estado de São Paulo

Candido¹

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egc characterization of enterotoxigenic Staphylococcus aureus isolates obtained from raw milk and cheese

Viçosa¹,

Loir²,

Loir³

et al. 2013

International Journal of Food Microbiology

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Genes encoding staphylococcal enterotoxins (SEs) are carried by mobile genetic elements, and enterotoxin gene clusters (egc) are pathogenicity island-borne structures comprising several SE genes, which are frequently found among clinical Staphylococcus aureus isolates. In the present study, we investigated the distribution and the genetic variability of egc loci in S. aureus strains isolated from raw milk and soft cheese in Minas Gerais, Brazil. Ninety-two isolates were submitted to PCR detection of individual egc-borne SE genes (seg, sei, sem, sen, seo, seu), and egc loci were typed using PCR-RFLP. PCR products of egc positive isolates were sequenced. Ninety-one isolates harbored at least one SE gene, which generated 14 different genotypes. The sei gene was the most widely distributed (97.8%), and was found in combination with seg in 49 isolates (53.3%). Altogether, a complete set of individual egc genes was detected in 37 isolates (40%). However, egc loci were detected by PCR-RFLP in only 4 isolates, and classified as egc1 (n=2), egc3 (n=1), and egc4 (n=1). This investigation demonstrated the low occurrence of the egc in S. aureus isolated from dairy products. However, the frequency of complete sets of individual egc-borne genes reflects either the presence of these SE genes outside egc or the existence of new egc types in these strains.

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Detecção de genes do cluster egc em Staphylococcus aureus isolados de alimentos de origem animal

Cited by 2 publications

References 16 publications

Fatores de virulência e subtipagem de Staphylococcus aureus isolados de laticínios orgânicos e convencionais no estado de São Paulo

Fatores de virulência e subtipagem de Staphylococcus aureus isolados de laticínios orgânicos e convencionais no estado de São Paulo

egc characterization of enterotoxigenic Staphylococcus aureus isolates obtained from raw milk and cheese

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