A strategy based on 5′ nuclease multiplex PCR to detect enterotoxin genes sea to sej of Staphylococcus aureus

Letertre, Capucine; Perelle, Sylvie; Dilasser, Françoise; Fach, Patrick

doi:10.1016/s0890-8508(03)00058-6

Cited by 32 publications

(14 citation statements)

References 37 publications

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“…Interestingly, all SFP isolates possessed the entA-320 variant, which was first detected in a French field isolate in 2003 [29]. While prevalence rates of entA and entC detected among SANC isolates in this study were almost identical to those of a study conducted with nasal carriage isolates of restaurant workers in Kuwait city, we found lower prevalence rates of entB, entD, and entE [30].…”

Section: Discussionsupporting

confidence: 59%

Comparison of Staphylococcus aureus isolates associated with food intoxication with isolates from human nasal carriers and human infections

Wattinger

Stephan

Layer

et al. 2011

Eur J Clin Microbiol Infect Dis

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Staphylococcus aureus represents an organism of striking versatility. While asymptomatic nasal colonization is widespread, it can also cause serious infections, toxinoses and life-threatening illnesses in humans and animals. Staphylococcal food poisoning (SFP), one of the most prevalent causes of foodborne intoxication worldwide, results from oral intake of staphylococcal enterotoxins leading to violent vomiting, diarrhea and cramps shortly upon ingestion. The aim of the present study was to compare isolates associated with SFP to isolates collected from cases of human nasal colonization and clinical infections in order to investigate the role of S. aureus colonizing and infecting humans as a possible source of SFP. Spa typing and DNA microarray profiling were used to characterize a total of 120 isolates, comprising 50 isolates collected from the anterior nares of healthy donors, 50 isolates obtained from cases of clinical infections in humans and 20 isolates related to outbreaks of staphylococcal food poisoning. Several common spa types were found among isolates of all three sources (t015, t018, t056, t084). DNA microarray results showed highly similar virulence gene profiles for isolates from all tested sources. These results suggest contamination of foodstuff with S. aureus colonizing and infecting food handlers to represent a source of SFP.

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Section: Discussionsupporting

confidence: 59%

Comparison of Staphylococcus aureus isolates associated with food intoxication with isolates from human nasal carriers and human infections

Wattinger

Stephan

Layer

et al. 2011

Eur J Clin Microbiol Infect Dis

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“…Recently, genetic comparison of six completely sequenced enterotoxigenic strains showed the presence of two main versions of the sea gene, sea 1 and sea 2 (3, 25). In addition, sea genes with a few nucleotide differences have been reported (3,9,12).The objectives of the present study were to systematically investigate the amounts of SEA produced by different S. aureus strains harboring sea, the genetic diversity of sea genes in relation to the levels of SEA produced, and the relationship between sea expression and the life cycle of the sea-encoding prophage. Twenty-one S. aureus strains, harboring sea 1 or sea 2 and including sequenced (whole genome) strains and food isolates, were investigated.…”

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confidence: 99%

mentioning

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Elevated Enterotoxin A Expression and Formation in Staphylococcus aureus and Its Association with Prophage Induction

Cao

Zeaki

Wallin-Carlquist

et al. 2012

Appl Environ Microbiol

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ABSTRACTStaphylococcus aureusstrains producing the bacteriophage-encoded staphylococcal enterotoxin A (SEA) were divided into two groups, high- and low-SEA-producing strains, based on the amount of SEA produced. After growth under favorable conditions in batch cultures, 10 of the 21 strains tested produced more than 1,000 ng/ml SEA, and 9 strains produced less than 10 ng/ml SEA; two enterotoxigenic strains, MRSA252 and Newman, produced intermediate levels of SEA (around 450 ng/ml). The differences in the production of SEA were found to be associated with the expression level ofseaand whether the strains hosted thesea1orsea2version. Furthermore, differences in nucleotide sequence in theSiphoviridaephage region showed two clonal lineages of the high-SEA-producing strains. One of these lines was correlated with the capacity for a massive increase in SEA levels by prophage induction as demonstrated using mitomycin C (MC). This was also confirmed by the occurrence of additionalseaexpression, presumed to be initiated by a latent phage promoter located upstream of the endogenousseapromoter. Remarkably, the SEA level was increased up to 10-fold in some strains due to prophage induction. The low-SEA-producing group and the high-SEA-producing subgroup lacking phage-activatedseatranscription showed no increase in SEA formation after the addition of MC. This study demonstrates thatseaexpression in enterotoxigenic strains is correlated with the clonal lineage ofsea-carrying phages. The high-SEA-producing group, in particular the prophage-induciblesea1group, may be more relevant to staphylococcal food poisoning than the low-SEA-producing group, harboring mainlysea2.

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“…Ikeda et al (2005b) untersuchten in Zusammenhang mit einem Ausbruch durch SEA-bildende S. aureus Milchpulver quantitativ auf sea, um damit indirekt auf die Belastung mit S. aureus zu schließen. Eine allgemeine Verwendung quantitativer PCR-Nachweise für SE-Gene zur Abschätzung des Toxingehaltes von Lebensmitteln ist jedoch bei unbekannten Proben kaum möglich, da die Nachweise aufgrund unterschiedlicher Nachweisgrenzen für die einzelnen Toxine für jedes Lebensmittel und jedes Toxin kalibriert werden müßten (Letertre et al, 2003a, Ercolini et al, 2004Nakayama et al, 2006).…”

Section: Polymerasekettenreaktionunclassified

Staphylokokken-Enterotoxine: Bildung, Eigenschaften und Nachweis

2007

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Zusammenfassung: Staphylococcus aureus kann sich unter geeigneten Bedingungen in Lebensmitteln vermehren und dabei Enterotoxine bilden, die beim Konsumenten Erbrechen und Durchfall auslösen. Im Gegensatz zu dem Erreger selbst sind diese Toxine sehr widerstandsfähig insbesondere gegenüber hohen Temperaturen und können durch eine küchenmäßige Bearbeitung des sie enthaltenden Lebensmittels im allgemeinen nicht mehr inaktiviert werden. Da demnach die Anwesenheit der Staphylokokken zur Auslösung der Erkrankung nicht mehr erforderlich ist, handelt es sich bei dieser um eine typische Lebensmittelintoxikation. Die Abschätzung einer potentiellen Gesundheitsgefährdung über den Erregernachweis ist daher nur bei rohen Lebensmitteln sinnvoll. Bei Produkten, die im Verlauf ihrer Herstellung einem für die Keime abträglichen Verfahren, z. B. einer Wärmebehandlung, unterzogen wurden, kann der Thermonukleasetest (indirekter Nachweis einer Kontamination mit hoher Anzahl an Staphylokokken, unabhängig davon, ob die Erreger zum Zeitpunkt der Untersuchung noch präsent sind) oder der direkte Enterotoxinnachweis durchgeführt werden. Der Nachweis der Toxingene mit molekularbiologischen Verfahren hat in diesem Zusammenhang nur unterstützende Funktion, da im Fall eines positiven Ergebnisses aus diesem nicht geschlossen werden kann, daß die Gene auch exprimiert wurden, also Toxine im Lebensmittel vorhanden sind. In der vorliegenden Übersichtsarbeit werden der Erreger und seine Enterotoxine sowie die verschiedenen Nachweisverfahren unter besonderer Berücksichtigung der molekularbiologischen Methoden besprochen.Abstract: Under appropriate conditions, Staphylococcus aureus can grow in food and produce enterotoxins which cause vomiting and diarrhoea when ingested. In contrast to the staphylococci these toxins are resistant especially to high temperatures and are not inactivated by usual kitchen practice. As the presence of staphylococci is not essential to cause illness, this condition is a typical food poisoning. The estimation of a potential health risk by targeting the organism is therefore only appropriate to raw food. For products which underwent a procedure detrimental to the bacteria, e. g. heat treatment, testing for thermonuclease (indirect detection of a contamination with high numbers of staphylococci, irrespective of the presence of living bacteria at the time of testing) or the detection of enterotoxins can be applied. In this context, the detection of enterotoxin genes using molecular biological tests provides only supplemental information, as positive results are not evidentiary for gene expression and thus for the presence of toxins in the food. In this review, the causative organism and its toxins as well as methods of detection are discussed with special emphasis on molecular biological methods.

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A strategy based on 5′ nuclease multiplex PCR to detect enterotoxin genes sea to sej of Staphylococcus aureus

Cited by 32 publications

References 37 publications

Comparison of Staphylococcus aureus isolates associated with food intoxication with isolates from human nasal carriers and human infections

Comparison of Staphylococcus aureus isolates associated with food intoxication with isolates from human nasal carriers and human infections

Elevated Enterotoxin A Expression and Formation in Staphylococcus aureus and Its Association with Prophage Induction

Staphylokokken-Enterotoxine: Bildung, Eigenschaften und Nachweis

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