[Which zoonosis is it?]. / Welche Zoonosen gibt es?

Starting from the definition for zoonoses according to EU directive 92/117 EEC a brief and mainly tabulated summary is given on the occurrence of zoonoses worldwide and in Germany and related factors.

Characterization of an extracellular metalloprotease with elastase activity from Staphylococcus epidermidis.

The gene sepA from Staphylococcus epidermidis TU3298-P, encoding the extracellular neutral metalloprotease SepP1, was cloned into pT181mcs. DNA sequencing revealed an open reading frame of 1,521 nucleotides encoding a 507-amino-acid protein with an M(r) of 55,819. The sepA-containing DNA fragment did not hybridize with Staphylococcus hyicus or Staphylococcus carnosus DNA. Expression of sepA in the protease-negative S. carnosus (pT181mcsP1) resulted in overproduction of a 33-kDa protease found in the culture medium. The first 15 N-terminal amino acids of the partially purified protease completely matched the deduced DNA sequence starting at GCA (Ala-208). This finding indicated that SepP1 is synthesized as a preproenzyme with a 28-amino-acid signal peptide, a 179-amino-acid hydrophilic pro region, and a 300-amino-acid extracellular mature form with a calculated M(r) of 32,739. In activity staining, the mature protease prepared from S. carnosus (pT181mcsP1) corresponded to the extracellular S. epidermidis Tü3298-P protease. The partially purified protease had a pH optimum between 5 and 7, and its activity could be inhibited by zinc- and metal-specific inhibitors such as EDTA and 1,10-phenanthroline, indicating that it is a neutral metalloprotease. The protease had a low substrate specificity. Glucagon was cleaved preferentially between aromatic (Phe) and hydrophobic (Val) amino acids. The protease hydrolyzed casein and elastin. The amino acid sequence of the mature form of SepP1 revealed pronounced similarities with the thermolabile and thermostable neutral proteases of various bacilli (44 to 55% identity) and a central part of the mature form of the Pseudomonas aeruginosa elastase (31% identity). From homology comparison with the Bacillus thermoproteolyticus thermolysin, we predict that mature SepP1 binds one zinc ion at a conserved zinc-binding site.

Notes on technical progress in veterinary public health.

Scientific and technical progress in the field of veterinary public health (VPH) over the last one hundred years has contributed to the protection of consumer health and the environment. This report presents examples of the success achieved in the control of epizootics of tuberculosis, brucellosis, rabies and trichinellosis, which are also zoonotic diseases. The discussion also considers hygiene measures in relation to Listeria in food as well as certain challenges resulting from the spread of latent infections among farm animals. The increasing incidence of Salmonella infections among humans is also considered. Other important VPH tasks include the control of chemical residues of varying origin and of toxic biological substances in foods. Examples are also presented of measures taken and problems which arise in connexion with ensuring that meat is produced under hygienic conditions (meat inspection). The principles involved in efficient controls of establishments and products are outlined. Technical progress in consumer protection is exemplified by the processes of pasteurisation, cooling and freezing, and the limitation of additives. Other important tasks arise in the disposal of animal carcasses and wastes, and in the fields of animal welfare and genetic engineering. Future activities in VPH will depend upon proper education, onward and postgraduate training for veterinarians, and suitable infrastructures for research, examination and surveillance.

[Recent bacterial risks in foods]. / Aktuelle Risikokeime in Lebensmitteln.

Knowledge about bacterial foodborne diseases has broadened over the last 15 years. To this development have contributed improved isolation and identification methods but also the application of systematic epidemiological studies. In principle, no "new" bacteria have been discovered but their occurrence in foods was not known (e.g. Campylobacter jejuni/coli) or their detection in foods could not be firmly linked with disease in man (e.g. Listeria monocytogenes, E. coli O157:H7). For campylobacteriosis, listeriosis and yersiniosis foods are considered to be the main source of infection. Many of these "new" agents cannot only be detected in diseased, but also in healthy man and the environment. Frequently importance of foods as source of infection can only be proved by epidemiological studies. Traditional isolation and identification procedures are not sufficient to differentiate between virulent and avirulent strains. Molecular genetic methods as applied for e.g. enterotoxigenic E. coli allow the detection of virulence factors, however, in many instances relationship is lacking between the frequency of detection of a certain strain in food and clinical manifestation of disease. In particular, the recent listeriosis problems reveal the importance of individual host defence mechanisms and infectious doses for the evaluation. These aspects challenge the ideal complete absence (i.e., zero tolerance) of a certain microorganism in a specific food.)

Serovars of Listeria monocytogenes and Listeria innocua from food.

The increase of listeriosis outbreaks in recent years has mainly been due to the consumption of contaminated dairy products. This prompted a revision of prevention and control measures. Cheese and other foods (meat, poultry meat) were investigated. For isolation, samples were prepared and investigated according to the recommendations of the FDA with some modifications including, in particular, sub-enrichment. Suspicious colonies were tested biochemically followed by serological identification with factor sera. Out of 100 chicken (95 broilers, 5 layers) Listeria monocytogenes was isolated from 85 carcases. The contamination rate for minced beef and pork (n = 76) was approximately 30%. That for selected ripened soft cheeses (n = 89) was 9%. The counts of Listeria in red meat were usually very low (approximately 10/g). Serovar 1/2a was predominant (78 out of 102 strains). Further serovars detected were: 1/2b, 1/2c, 3a, 4a, 4b, 4d. For comparison, isolated strains of L. monocytogenes and Listeria innocua were inoculated into chicken embryos. In contrast to the former, L. innocua did not kill the embryos.