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Mossong J.,Laboratoire National Of Sante | Decruyenaere F.,Laboratoire National Of Sante | Moris G.,Laboratoire National Of Sante | Ragimbeau C.,Laboratoire National Of Sante | And 3 more authors.
Eurosurveillance | Year: 2015

In June 2014, a staphylococcal food poisoning outbreak occurred at an international equine sports event in Luxembourg requiring the hospitalisation of 31 persons. We conducted a microbiological investigation of patients and buffet items, a case–control study and a carriage study of catering staff. Isolates of Staphylococcus aureus from patients, food and catering staff were characterised and compared using traditional typing methods and whole genome sequencing. Genotypically identical strains (sequence type ST8, spa-type t024, MLVA-type 4698, enterotoxin A FRI100) were isolated in 10 patients, shiitake mushrooms, cured ham, and in three members of staff. The case–control study strongly suggested pasta salad with pesto as the vehicle of infection (p<0.001), but this food item could not be tested, because there were no leftovers. Additional enterotoxigenic strains genetically unrelated to the outbreak strain were found in four members of staff. Non-enterotoxigenic strains with livestock-associated sequence type ST398 were isolated from three food items and two members of staff. The main cause of the outbreak is likely to have been not maintaining the cold chain after food preparation. Whole genome sequencing resulted in phylogenetic clustering which concurred with traditional typing while simultaneously characterising virulence and resistance traits. © 2015, European Centre for Disease Prevention and Control (ECDC). All rights reserved. Source

Hachler H.,National Center for Enteropathogenic Bacteria and Listeria | Hachler H.,Institute for Food Safety and Hygiene | Marti G.,Cantonal Laboratory | Giannini P.,Cantonal Laboratory | And 8 more authors.
Eurosurveillance | Year: 2013

From 24 April to 31 July 2011, nine cases of listeriosis were registered in the cantons of Aargau, Basel-Land and Zurich, Switzerland. In six of the cases, infection with Listeria monocytogenes was laboratory confirmed, while three remained suspected cases. The suspected cases were family members of confirmed cases with identical or similar symptoms. All confirmed cases were infected with a L. monocytogenes strain belonging to serovar 1/2a: all had an indistinguishable pulsotype by pulsed-field gel electrophoresis (PFGE). The same strain was detected in samples of cooked ham that were on sale from a particular retailer. Two samples of ham tested contained 470 and 4,800 colony-forming units (CFU) L. monocytogenes per gram respectively. Data of shopper cards from two confirmed cases could be evaluated: both cases had purchased the contaminated ham. The outbreak initiated a product recall and alert actions at national and European level, through the Rapid Alert System for Food and Feed (RASFF). Following the RASFF alert, the company producing the contaminated ham was inspected by the responsible authorities. Their investigations showed that the ham was not contaminated in the production plant, but in the premises of a company to which slicing and packing was outsourced. Source

Johler S.,Institute for Food Safety and Hygiene | Giannini P.,Cantonal Laboratory | Jermini M.,Cantonal Laboratory | Hummerjohann J.,Institute for Food science | And 2 more authors.
Toxins | Year: 2015

Staphylococcal food poisoning represents the most prevalent foodborne intoxication worldwide. It is caused by oral intake of enterotoxins preformed by Staphylococcus aureus in food. The relevance of newly described enterotoxins in outbreaks of staphylococcal food poisoning is controversially discussed. Although the staphylococcal enterotoxins SEG, SEI, SEM, SEN, and SEO elicit emesis in a monkey feeding assay, there has been no conclusive proof of their emetic activity in humans. In this study, we provide further evidence suggesting that one of these enterotoxins or a combination of SEG, SEI, SEM, SEN, and SEO cause staphylococcal food poisoning. We investigated two outbreaks registered with the Swiss Federal Office of Public Health, in which only Staphylococcus aureus strains harboring the egc cluster, including seg, sei, sem, sen, and seo linked to typical signs of staphylococcal food poisoning were isolated. The outbreaks were caused by consumption of raw goat cheese and semi-hard goat cheese, and were linked to strains assigned to CC45 (agr type I) and CC9 (agr type II), respectively. These outbreaks provide further evidence that newly-described staphylococcal enterotoxins are likely to cause staphylococcal food poisoning in humans. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source

Nuesch-Inderbinen M.T.,Institute for Food Safety and Hygiene | Hofer E.,Institute for Food Safety and Hygiene | Hachler H.,Institute for Food Safety and Hygiene | Beutin L.,German Federal Institute for Risk Assessment | Stephan R.,Institute for Food Safety and Hygiene
Journal of Medical Microbiology | Year: 2013

The aim of this study was to compare the virulence characteristics and phylogenetic features of enteroaggregative Escherichia coli (EAEC) strains from adults with and without diarrhoea and to search for associations between the analysed genes and carrier or diarrhoeagenic strains, respectively. Faecal samples of 487 healthy humans were screened for EAEC strains and compared with isolates from diarrhoeal patients. Virulence and virulence-associated gene typing, serotyping, multilocus sequence typing and antibiotic susceptibility testing were performed for characterization of the isolates. Characteristics significantly linked to carrier strains or to diarrhoeagenic strains were determined. From 487 stool samples, 24 EAEC strains were obtained. Comparison with strains originating from diseased persons showed a statistically significant association of the genes sat (P = 0.002) and agg3C (P = 0.0139) with the carrier strains, and of pCVD432 (P = 0.0001), aap (P = 0.003), aggR (P = 0.0048) and air (P = 0.031) with the diarrhoeagenic strains. Our study indicates that a certain subset of EAEC is unrelated to diarrhoea, for which sat and agg3C may be markers. Our results further suggest that diarrhoeagenic EAEC strains are distinguishable from carrier strains and suggest that, in addition to well-established markers such as pCVD432 and aggR, aap and air may be useful additional markers to define EAEC as an aetiological agent of diarrhoea in adults. © 2013 SGM. Source

Johler S.,Institute for Food Safety and Hygiene | Sihto H.-M.,Institute for Food Safety and Hygiene | Macori G.,National Reference Laboratory for Coagulase Positive Staphylococci including Staphylococcus aureus | Stephan R.,Institute for Food Safety and Hygiene
Toxins | Year: 2016

Ingestion of staphylococcal enterotoxins preformed by Staphylococcus aureus in food leads to staphylococcal food poisoning, the most prevalent foodborne intoxication worldwide. There are five major staphylococcal enterotoxins: SEA, SEB, SEC, SED, and SEE. While variants of these toxins have been described and were linked to specific hosts or levels or enterotoxin production, data on sequence variation is still limited. In this study, we aim to extend the knowledge on promoter and gene variants of the major enterotoxins SEB, SEC, and SED. To this end, we determined seb, sec, and sed promoter and gene sequences of a well-characterized set of enterotoxigenic Staphylococcus aureus strains originating from foodborne outbreaks, human infections, human nasal colonization, rabbits, and cattle. New nucleotide sequence variants were detected for all three enterotoxins and a novel amino acid sequence variant of SED was detected in a strain associated with human nasal colonization. While the seb promoter and gene sequences exhibited a high degree of variability, the sec and sed promoter and gene were more conserved. Interestingly, a truncated variant of sed was detected in all tested sed harboring rabbit strains. The generated data represents a further step towards improved understanding of strain-specific differences in enterotoxin expression and host-specific variation in enterotoxin sequences. © 2016 by the authors; licensee MDPI, Basel, Switzerland. Source

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