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Seit November 2012 wurden in Suddeutschland gehauft humane Listeriosefalle mit einem bestimmten Listerien-Feintypmuster (PFGE Typ 13a/54, NGS-Clustertyp 1248) beobachtet. Da die Listeriose als klassische Zoonose gilt und die Ubertragung im Wesentlichen durch den Verzehr von mit Listeria (L.) monocytogenes kontaminierten Lebensmitteln erfolgt, versuchten die zustandigen Gesundheitsbehorden durch umfassende Befragungen eine gemeinsame Expositionsquelle bei den erkrankten Personen zu ermitteln. Allerdings war es lange Zeit trotz umfangreicher epidemiologischer Untersuchungen nicht moglich, die Ursache der Erkrankungen auf eine bestimmte Lebensmittelkategorie einzugrenzen, die Herkunft des Erregers blieb unklar. Mitte Marz 2016 wurde allerdings bei einer im Rahmen des amtlichen Probenplans auf Einzelhandelsebene entnommenen Probe von „Original bayerisches Wacholderwammerl“ am Bayerischen Landesamt fur Gesundheit und Lebensmittelsicherheit (LGL) L. monocytogenes in hoher Keimzahl festgestellt. Es erfolgte ein Ruckruf der betroffenen Ware, das gewonnene Isolat wurde zur weitergehenden Typisierung an das Bundesinstitut fur Risikobewertung (BfR) weitergeleitet. Dort wurde im Rahmen der Typisierung das gleiche NGS-Muster wie bei den Patienten-Isolaten nachgewiesen, so dass sich erstmalig ein Lebensmittel dem humanen Ausbruchsgeschehen zuordnen lies. Bei weiteren Probenahmen von Wammerl-Produkten der betroffenen Betriebsstatte sowohl im Betrieb selbst als auch im Einzelhandel wurden direkt im Anschluss an den Ruckruf ebenfalls L. monocytogenes-Stamme mit einem zum Ausbruchstamm identischen PFGE- und NGS-Muster isoliert. Auch epidemiologische Erkenntnisse zu dem Produkt des betroffenen Betriebes deuteten darauf hin, dass mit hoher Wahrscheinlichkeit ein Zusammenhang der Erkrankungsfalle mit Produkten aus dem betroffenen Betrieb besteht.

Clostridium perfringens is a Gram-positive, anaerobic bacterium. The strains are classified into five types (type A to E), depending on the ability to produce alpha-, beta-, epsiloon and iota-toxin, but food-poisonings are mostly caused by C. perfringens type A isolates. Ingestion of contaminated food is followed by gastrointestinal disease, when enzyme-resistant C. perfringens enterotoxins (CpE) are set free during sporulation. In most cases the bacterium has to grow up to more than 106 cfu/g food to cause a gastrointestinal disease (BVET, 2005; BfR, 2005). Cultural methods, normally used for the detection of C. perfringens, are not able to differentiate isolates into the five different toxin types. This is the reason, why the detection of C. perfringens in food under the present legal regulations can only used as an indication for inadequate production hygiene or a toxin-infection with contaminated food as source. For the detection of the toxin genes to differentiate C. perfringens in five different toxin types, three duplex real-time-PCR assays for the routine diagnostic were developed and validated. The assays can be used for quick detection and easy classification of C. perfringens isolates and as a rapid screening-system in suspected cases of C. perfringens food-poisonings.

Enterohaemorrhagic Escherichia coli (EHEC) are among the most important bacterial causes of food-borne gastrointestinal infections in Germany. Because of the occurrence of post-infectious syndromes leading to severe organic damages and even death particularly among children, and with respect to the very low infection dose, EHEC may not be present in 25 g of consumable food. In this study, the PCR method enlisted in the Official Collection of Methods established pursuant to Article 64 of the German Food and Feed Law (Lebensmittel- und Futtergesetzbuch, LFGB) and a real-time PCR procedure were compared regarding their diagnostic outcome using both isolated DNA and routine samples samples (sent in for human and/or veterinary microbiological diagnostics as well as for environmental water and/or food diagnostics). The real-time PCR procedure showed a higher sensitivity in both diagnostic settings. A positive result by bacterial culture, however, which is needed for an assessement according to the Food and Feed Law regulations was not achieved in all real time- PCR positive probes.

Background Tularemia is a zoonotic disease caused by Francisella tularensis that has been found in many different vertebrates. In Germany most human infections are caused by contact with infected European brown hares (Lepus europaeus). The aim of this study was to elucidate the epidemiology of tularemia in hares using phenotypic and genotypic characteristics of F. tularensis. Results Cultivation of F. tularensis subsp. holarctica bacteria from organ material was successful in 31 of 52 hares that had a positive PCR result targeting the Ft-M19 locus. 17 isolates were sensitive to erythromycin and 14 were resistant. Analysis of VNTR loci (Ft-M3, Ft-M6 and Ft-M24), INDELs (Ftind33, Ftind38, Ftind49, RD23) and SNPs (B.17, B.18, B.19, and B.20) was shown to be useful to investigate the genetic relatedness of Francisella strains in this set of strains. The 14 erythromycin resistant isolates were assigned to clade B.I, and 16 erythromycin sensitive isolates to clade B.IV and one isolate was found to belong to clade B.II. MALDI-TOF mass spectrometry (MS) was useful to discriminate strains to the subspecies level. Conclusions F. tularensis seems to be a re-emerging pathogen in Germany. The pathogen can easily be identified using PCR assays. Isolates can also be identified within one hour using MALDI-TOF MS in laboratories where specific PCR assays are not established. Further analysis of strains requires genotyping tools. The results from this study indicate a geographical segregation of the phylogenetic clade B.I and B.IV, where B.I strains localize primarily within eastern Germany and B.IV strains within western Germany. This phylogeographical pattern coincides with the distribution of biovar I (erythromycin sensitive) and biovar II (erythromycin resistance) strains. When time and costs are limiting parameters small numbers of isolates can be analysed using PCR assays combined with DNA sequencing with a focus on genetic loci that are most likely discriminatory among strains found in a specific area. In perspective, whole genome data will have to be investigated especially when terrorist attack strains need to be tracked to their genetic and geographical sources.

Tissue culture cells' metabolism and viability are measured by the mitochondrial reduction rate of a yellow tetrazolium salt (MTT) to blue formazan crystalls in the MTT-bioassay. Thus the MTT-bioassay is a standardizable and reproducible bioassay for measuring cytotoxicity or cytostimulation. It is shown that the MTT-bioassay is also very suitable for determining bacterial cytotoxins using Escherichia coli's Shiga-like toxins as example. 177 strains ofE.coli, isolated from carcasses and organs of cattle, are classified biochemically and tested for cytotoxin production by means of the MTT-bioassay. One of these strains is recognized as producer of Shiga-like toxin 2. 4 Enterohemolysin-producing strains ofE.coli are cultivated from a feces sample of a diarrhoeic nubian ibex and identified as Shiga-like toxin 1 producers by help of the MTT-bioassay.