Several Bacillus cereus strains possess the genetic fittings to produce two different types of toxins, the heat-stable cereulide or different heat-labile proteins with enterotoxigenic potential. Unlike the diarrheal toxins, cereulide is (pre-)formed in food and can cause foodborne intoxications shortly after ingestion of contaminated food. Based on the widely self-limiting character of cereulide intoxications and rarely performed differential diagnostic in routine laboratories, the real incidence is largely unknown. Therefore, during a 7-year period about 4.300 food samples linked to foodborne illness with a preliminary report of vomiting as well as food analysed in the context of monitoring programs were investigated to determine the prevalence of emetic B. cereus in food environments. In addition, a lux-based real-time monitoring system was employed to assess the significance of the detection of emetic strains in different food matrices and to determine the actual risk of cereulide toxin production in different types of food. This comprehensive study showed that emetic strains are much more volatile than previously thought. Our survey highlights the importance and need of novel strategies to move from the currently taxonomic-driven diagnostic to more risk orientated diagnostics to improve food and consumer safety.

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Microbial batch production of alcohols by fermentation of CO-rich gases with Clostridia is limited by low volumetric productivities due to the need for formation of organic acids first (acidogenic phase) followed by re-consumption of the acids to form alcohols (solventogenic phase). Continuous autotrophic production of alcohols was made possible with C. carboxidivorans by use of two continuously operated stirred-tank bioreactors in series without cell retention. The pH in the first reactor was controlled to pH 6.0 for continuous growth of the cells. Steady-state concentrations of 3.0 g L acetate and 0.1 g L butyrate were measured at a mean hydraulic residence time of 8.3 h. The pH in the second reactor was controlled to pH 5.0 for enhancing continuous formation of alcohols resulting in steady-state concentrations of 6.1 g L ethanol, 0.7 g L butanol, and 0.1 g L hexanol at a mean hydraulic residence time of 12.5 h. Continuous formation of alcohols from CO was already observed in the first stirred-tank reactor parallel to the formation of acids, whereas re-consumption of acids as well as de-novo syntheses of alcohols from CO was shown in the second stirred-tank reactor. Thus, high final alcohol-to-acid ratios of 3.9 g g and 4.4 g g were achieved in the continuous syngas-fermentation process with C. carboxidivorans.

Ampicillin and vancomycin are important antibiotics for the therapy of Enterococcus faecalis infections. The ampicillin resistance gene pbp5 is intrinsic in Enterococcus faecium. The vanC1 gene confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Both genes are chromosomally located. Resistance to ampicillin and vancomycin was determined in 484 E. faecalis of human and porcine origin by microdilution. Since E. faecalis are highly skilled to acquire resistance genes, all strains were investigated for the presence of pbp5 (and, in positive strains, for the penicillin-binding protein synthesis repressor gene psr) and vanC1 (and, in positive strains, for vanXYc and vanT) by using polymerase chain reaction (PCR). One porcine and one human isolate were phenotypically resistant to ampicillin; no strain was vancomycin resistant. Four E. faecalis (3/1 of porcine/human origin) carried pbp5 (MIC=1 mg/L), and four porcine strains were vanC1 positive (minimum inhibitory concentration [MIC]=1 mg/L). Real-time reverse transcriptase (RT)-PCR revealed that the genes were not expressed. The psr gene was absent in the four pbp5-positive strains; the vanXYc gene was absent in the four vanC1-positive strains. However, vanT of the vanC gene cluster was detected in two vanC1-positive strains. To our knowledge, this is the first report on the presence of pbp5, identical with the "E. faecium pbp5 gene," and of vanC1/vanT in E. faecalis. Even if resistance is not expressed in these strains, this study shows that E. faecalis have a strong ability to acquire resistance genes-and potentially to spread them to other bacteria. Therefore, close monitoring of this species should be continued.