Molecular Characterization of Extended-Spectrum ß-Lactamase-Producing Escherichia coli Isolates from Milk Samples of Dairy Cows with Mastitis in Bavaria, Germany.

The aim of this study was to determine the rate of extended-spectrum ß-lactamase (ESBL)-producing microorganisms among Escherichia coli isolates causing bovine mastitis, including molecular characterization of these isolates. Therefore, a total of 490 bovine E. coli isolates from milk samples of dairy cows with mastitis were investigated for ESBL production by antimicrobial susceptibility testing, PCR-based detection, and sequencing of ESBL encoding genes, which were identified in 22 isolates (4.5%). Moreover, resistance to the fluoroquinolones enrofloxacin and marbofloxacin occurred in 15 of 22 ESBL-producing isolates (68.2%). All ESBL-producing isolates carried a blaCTX-M-like gene, with blaCTX-M-14 (n = 10) as the most prevalent type. Seven isolates producing CTX-M-14 and belonging to phylogenetic group A were further investigated for genetic relatedness by multilocus sequence typing. Five of them could be assigned to four different sequence types (STs): ST10 (n = 2), ST167 (n = 1), ST410 (n = 1), and ST744 (n = 1), whereas the remaining two isolates could not be assigned. To conclude, the rate of ESBL-producing E. coli associated with cattle mastitis was 4.5%. Furthermore, a high proportion of fluoroquinolone coresistance could be detected. Therefore, careful and continuous surveillance of ESBL-producing E. coli in cattle and consequent implementation of prevention measures are needed to avoid a further spread of these multidrug-resistant bacteria.

Action Levels for Food Allergens: An Approach for Official Food Control in Germany.

Official food control laboratories in Germany have established internal action values for the assessment of analytical results of food allergens especially obtained from samples without declaration of the specified allergen. A pragmatic approach was chosen considering the current situation for European food information legislation. Accordingly, when a positive result is obtained for an unlabeled allergen, it is not necessarily an irregularity if it can be demonstrated that the result was caused by cross-contamination. Action values take into account current analytical experiences as well as published allergologic reference doses. They are considered as internal de minimis thresholds by food control authorities that are used to support laboratories in the decision-making process and when a written expert opinion is requested by an enforcement authority. If only minor traces are detected at concentrations below the action values, further investigation of the issue and inspections at the location of manufacture can be abandoned. The present report includes a collection of results from official food control laboratories in Germany that have been evaluated in line with the aforementioned system of action levels.

Immunochemical detection of tissue from the central nervous system via myelin proteolipid protein: adaptation for food inspection and development of recombinant bivalent Fab mini-antibodies.

Bovine spongiform encephalopathy (BSE) is transmitted by the ingestion of central nervous system (CNS) tissue of infected animals. Food inspection must, therefore, test for the presence of CNS tissue in meat and meat products. A Western blot assay for the specific CNS tissue marker myelin proteolipid protein (PLP) was optimized with considerably reduced analysis time, solvent consumption, and detection limit (0.001% CNS tissue in minced beef). Further, a PLP-specific recombinant bivalent fragment antigen binding mini-antibody (anti-PLP Fab) was obtained from a commercial phage display library. Western blot analysis with the anti-PLP Fab selectively detected CNS tissue in minced beef with a detection limit of 0.025%. Model experiments for meat processing revealed that assay sensitivity decreased with increasing temperature and prolonged heating time. A market survey with 687 sausage samples was performed using PLP-Western blot and enzyme-linked immunosorbent assay (ELISA) for glial fibrillary acidic protein (GFAP). Five samples were tested clearly positive by both assay systems, whereas in an additional six samples, CNS tissue was detected only by GFAP ELISA and in two samples only by PLP-Western blot.