Summary: In a survey on the occurrence of Vibrio parahaemolyticus and V. alginolyticus on mussels and oysters and in estuarine waters in The Netherlands it appeared necessary to use at least 2 different enrichment procedures as well as isolation methods in parallel to obtain reliable results. A consistent identification of V. parahaemolyticus on biochemical grounds remains a difficult task; further research in this area is definitely required. The ligated intestinal segment technique gave inconsistent results; injection of organisms into the yolk sac of fertilized hen eggs seems to be a more reliable diagnostic procedure. Of 288 samples of mussels examined 2·4% were V. parahaemolyticus positive, 80 samples of oysters were all negative and amongst 64 water samples 4·7% were positive. V. alginolyticus was isolated in similar percentages of samples of mussels and water, but oysters were positive to an extent of 6·8%.
SUMMARYA survey was carried out on the occurrence of Vibrio parahaemolyticus on fish and shellfish, as sold in The Netherlands.The optimal mode of detection of this bacterium appeared to be: (i) enrichment of swabs taken from the surface and the gills in freshly prepared meat broth with 5 % NaCl; (ii) streaking onto Teepol bromothymol blue agar (BTB) and taurocholate bromothymol blue sucrose agar (TCBS); (iii) confirmation of suspect colonies by testing for mode of growth in butts/slants of a Kligler type glucose sucrose iron thiosulphate agar, formation of indole in 2 % NaCl 2 % trypticase water, anaerobic utilization of starch in the presence of 5 % NaCl and oxidase reaction according to Kovacs (1956).A total of 407 samples, stemming from 17 types of fish and shellfish, taken at three fish shops, was examined by this technique. Only one specimen, i.e. a haddock, was found to contain V. parahaemolyticus. This contamination rate of approximately 0-3 % correlates well with data found earlier for fish landed in Northern Germany.
Four consecutively produced batches of Bacillus Calmette-Guérin (BCG) especially intended to be used for cancer immunotherapy were investigated for consistency of the vaccine. Each batch was investigated directly after production of the vaccine, so that the four batches were not tested simultaneously. The activity of the four batches was investigated in general safety assays, immunostimulation assays, and two different tumor models. General safety assays showed dose-dependent growth retardation and increased serum glutamic pyruvic transaminase activity in mice, and a long-lasting temperature rise in rabbits after IV administration of the BCG preparations. In a skin reactivity assay, reactions were found acceptable for all preparations when compared with a reference batch. The results of the immunostimulation and antitumor studies can be summarized as follows. All four batches induced a specific delayed-type hypersensitivity reaction to PPD, indicating the induction of cell-mediated immunity. A stimulating effect on lymphoreticular organs was concluded from increased spleen weight and enhanced cell proliferation in draining lymph nodes. Enhanced macrophage function (phagocytosis and killing of bacteria) was demonstrated by an increased resistance to Listeria monocytogenes. YAC lymphoma target cells were killed nonspecifically by BCG-activated peritoneal exudate cells (PEC), indicating the induction of natural killing activity by BCG. Intralesional injection of BCG induced tumor regression in the guinea pig line 10 hepatocellular carcinoma, followed by immunity to the line 10 tumor. In the murine 5D04 squamous cell carcinoma, BCG had no effect on the primary tumor. However, IV-injected BCG resulted in a decreased number of lung metastases. In general, the four consecutively produced batches showed similar safety and activity in the immunostimulation assays and antitumor activity. Since only minor differences between the batches were found, which can also be attributed to the variation in experimental conditions common to biological assays, it is concluded that the vaccine batches produced show an acceptable consistency.
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