Isolation of Bacillus cytotoxicus from various commercial potato products.

Bacillus (B.) cytotoxicus is a newly described thermotolerant member of the Bacillus cereus group. This potential foodborne pathogen had so far only been isolated from vegetable products, including mashed potatoes. Here we report the detection of B. cytotoxicus in a variety of potato products taken on retail level or from catering establishments (n=151). Identification of isolates as B. cytotoxicus was performed after enrichment at 50°C, followed by differentiation using Fourier transform-infrared spectroscopy and detection of the specific cytK-1 gene by PCR. Thirty-five percent of all samples were positive for B. cytotoxicus. Highest prevalence was found in dehydrated potato products (44/62=71%) such as powder for mashed potatoes and products made thereof. B. cytotoxicus was not detected in products that were evidently made directly from potatoes (n=24) but in one sample of raw potatoes (n=10; 10%). The high prevalence of this thermotolerant pathogen in potato products could pose a risk for consumers, especially if prepared foods are held at improper holding temperatures.

Yersinia enterocolitica in diagnostic fecal samples from European dogs and cats: identification by fourier transform infrared spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Yersinia enterocolitica is the main cause of yersiniosis in Europe, one of the five main bacterial gastrointestinal diseases of humans. Beside pigs, companion animals, especially dogs and cats, were repeatedly discussed in the past as a possible source of pathogenic Y. enterocolitica. To investigate the presence and types of Y. enterocolitica in companion animals, a total of 4,325 diagnostic fecal samples from dogs and 2,624 samples from cats were tested. The isolates obtained were differentiated by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and Fourier transform infrared spectroscopy (FT-IR). Isolated Y. enterocolitica strains were bioserotyped. The detection of the ail gene by PCR and confirmation by FT-IR were used as a pathogenicity marker. Y. enterocolitica strains were isolated from 198 (4.6%) of the dog and 8 (0.3%) of the cat fecal samples investigated. One hundred seventy-nine isolates from dogs were analyzed in detail. The virulence factor Ail was detected in 91.6% of isolates. Isolates of biotype 4 (54.7%) and, to a lesser extent, biotypes 2 (23.5%), 3 (11.2%), and 5 (2.2%) were detected. The remaining 8.4% of strains belonged to the ail-negative biotype 1A. All 7 isolates from cats that were investigated in detail were ail positive. These results indicate that companion animals could be a relevant reservoir for a broad range of presumptively human-pathogenic Y. enterocolitica types. MALDI-TOF MS and FT-IR proved to be valuable methods for the rapid identification of Y. enterocolitica, especially in regard to the large number of samples that were investigated in a short time frame.