Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene. Erste Abteilung Originale. Reihe B: Hygiene, Betriebshygiene, praventive Medizin最新文献

Bacteriological drinking water examination of samples from water works and wells as well as from their distribution systems revealed that from 26 samples, where Salmonella organisms could be isolated, in 16 cases E. coli- and coliforms could not be found and that in 9 of these cases even the colony count was below 100 colonies per ml at 20 degrees C and 37 degrees C incubation temperature. The common reasons for such contaminations are technical deficiencies, mostly faulty well-heads or broken covers of reservoirs. Rainbow lizzards (Agama agama), very common in these regions, can thus easily gain access to wells and reservoirs and pollute the groundwater. Rainbow lizzards do not posses a constant and uniform microbial flora of the intestine. Among lizzards which excrete Salmonella organisms in great numbers, relatively often individuals could be found which harbour either no E. coli- and/or coliforms at all or only in very reduced numbers. In the light of these results an efficient primary protection of all water supplies by a secure covering of well-heads and reservoirs in particular seems to be of paramount importance in tropical countries. This is very much in contrast to the situation most commonly seen in these areas. The necessary measures would have to be accompanied and supplemented by alterations of the installations in the house where the creation of open reservoirs must be avoided.

149 Micrococcaceae strains (35 reference strains and 114 strains isolated from meat and dairy products) have been studied using 61 biochemical microtests. Numerical taxonomy has distinguished two main biochemical groups which may be characterized by their varying ability to use heteroside compounds. -- A small number of biochemical tests in each group enable the differentiation of 17 taxa corresponding to diverse origins. The wild strains of Micrococcaceae found in foods are very different from reference strains in collections. -- With regard to the present study, it seems that a central biotype exists which may be represented by the taxa 13, 14, 15 and 16 in Fig. 1. -- Given this central biotype, various biochemical differences may be considered as ecological adaptability. Group I corresponds to meat orgin -- Taxa No. 1, 2, correspond to collection strains -- Taxon No. 12 corresponds to cheese origin -- Taxa No. 8, 9 and 10 correspond to milk origin.

Measuring the potential soil respiration according to the incubator method allows the physiological performance of the celluloytic microflora to be determined. Laboratory tests were carried out to analyse catabolic processes after soil samples had been enriched with native cellulose + fungides. As the temporary capacity of mineralization primarily induced by the substrate invariably gives rise to a substrate-specific "change in position" in the microbial biocenosis, the measured values cannot furnish a parameter for microbiological comparisons of the soil content. Preliminary analyses provided information on the processes of depolymerisation of various C-sources and characterized the celluloysis as well as the order of respiration of its monomer. The rising respiration curve markedly drops off after 12 days, because with the CO2 development at its maximum, total and partial respiration alternate, a phenomenon that was verified in soils incubated with glucose 14C (Keefer and Mortensen, 1963; Macura, 1963; Simonart and Mayaudon, 1958). The test results obtained with fungicide-treated soils (dithiocarbamine acid derivatives) allow the conclusion that the fungicides exercise a varying influence: in the cellulolysis the activity of the cellulase systems is reduced depending on the active substance and concentration, but what is surprising is that respiration is stimulated; this applies to amounts of pesticides being 0.75 and 1.5 times the practical quantity applied. Nor have the "dissociation tests" with cellobiose, which is supposed to be the final link of celluloysis, shown any inhibition of the 1.4--glucodimerase or high respiration values comparable with the glucose metabolism. Tests with cellulases (Cx with dimerase function, Messrs. Roehm and Haas, Darmstadt), which are at present being carried out, are expected to support these observations experimentally. Investigations intended to clarify whether an additional administration of Mn2+ and Fe3+ in the presence of Maneb and Ferbam permits interference with possible adsorption and exchange processes have not yet yielded any generally valid results. The results of the open-field investigations also tend to indicate that the mentioned dithio-carbamates determine the magnitude and the extent of the physiological and CO2-ecological processes to a varying degree; it can be seen that a remarkable "capacity fo compensation" is discernible in the succession of the investigated phases of soil-physiological processes which we tried to clarify.

In applying S. mendoza the following four liquid media were tested as to whether they can be used as enrichment broths for salmonellae in milk powder: phosphate buffered water, correspondingly buffered peptone broth, tetrathionate and selenite lactose broth. The yield of salmonellae in these tests is largely independent of the starting pH value of the prepared milk suspension which was varied between 5.8 and 8.2 (Fig. 1). In water the pH dropped within 24 hours (Fig. 2), in peptone and tetrathionate broth within 48 hours down to figures between 4.1 and 4.4 (Fig. 3 and 4), in selenite broth final figures of pH 5.7 were not attained before the lapse of 6 days (Fig. 5). The absolutely highest germ figures were observed in selenite broth. Quite in general the bacteria figure maximum was not attained until the 3rd--5th day, whereupon the germ figures dropped again. In peptone broth the introduced salmonellae were recovered in 73% of all cases after the lapse of 24 hours. Also in tetrathionate the success quota was about 73%, but part of it (8%) did not increase until a lapse of more than 72 hours incubation time, although the pH had already become strongly acid some days previously. In water the introduced salmonellae were traced only in 67%, in selenite broth even only in 61%. Also the time until the first detection increased a little in these media (Table 1). The period during which salmonellae were traceable was equally highest in peptone broth being 57% relative to the complete testing period (tetrathionate: 55%, water: 51%, selenite: 39% (Table 1). This permits the conclusion that peptone broth is the best preenrichment medium in which salmonellae may become traceable after a lapse of approx. 24 hours. Not considerably more unfavourable is the tetrathionate broth which so far had been considered as an exclusive selectivity medium. In this context it is, however, necessary to face the possibility that predamaged salmonellae do not begin to increase until the end of some days incubation and even at a strongly acid pH.

The experiments describe the effects of short-term application of low concentrations of lead on the elimination of bacteria in the lungs of laboratory animals. On five subsequent days over a period of three weeks female mice of the NMRI strain were exposed for one and three hours, respectively, to a lead aerosol (mean concentration 13,14 micrograms/m3 lead chloride). Then the animals inhaled FITC labeled non pathogenic bacteria of the species Serratia marcescens. The lungs of the animals examined were analyzed for: a) free fluorescent bacteria in the pulmonary tissue, in the alveoles, bronchioles and bronchi; b) phagocytising alveolar macrophages; c) non-phagocytising alveolar macrophages. The following results have been established: 1. Under the given test conditions a three hour inhalation of lead chloride induces a significant reduction in the elimination of the bacteria. A one hour inhalation causes differences between the mean values of the test group and a control group on nearly all the days of experiments. On the 10th, 13th and 14th day of inhalation a signifcant difference between both groups could be established. The number of bacteria fluctuates largely from one day of test to the next, including a weekly rhythm. 2. Comparing the test group with the control group with respect to the parameters "phagocytising alveolar macrophages" and "free bacteria" as well, one can notice for the one hour lead chloride inhalation particularly high numbers obtained on weekends. The number of phagocytising alveolar macrophages tends to increase after a one hour lead chloride inhalation period during the third week of the experiment. This indicates a reactive increase of phagocytosis stimulated by the increased uptake of bacteria. Contrary after a three hour inhalation period of lead chloride during the third week from the 11th to the 15th day of testing, no further reactive increase in the number of phagocytising alveolar macrophages can be established. . A comparison of the number of non phagocytising alveolar macrophages did not reveal any differences between the mean values of the test groups for one hour and three hour inhalations compared to the control groups.

Of the numerous zoonoses part of which are reportable, according to the Federal Communicable Diseases Act, the food hygienist attributes topicality at present to salmonellosis, brucellosis, toxoplasmosis, taeniasis (T. saginata), trichinellosis, and sarcosporidiosis. In salmonellosis, combating is directed to breeding and keeping of Salmonella-free flocks, poultry offering favourable conditions for this purpose. Moreover, one tries to decontaminate feeds through certain pelleting machines with the aid of friction heat or by admixing propionic acid. In brucellosis, the possibility of infection by tourism, but also that through ingestion of imported dairy products (like soft cheese) play a certain role. Instruction of tourists and advising foreign labour from endemic areas are essential contributions to combating. Another important infection source of toxoplasmosis is infected raw pig meat. As the agent does not survive freezing temperatures under certain conditions, the decontamination procedure is particularly suitable. In pregnancy advising, the role of raw pig meat for development of congenital toxoplasmosis should be clearly explained. In trichinellosis, apart from the traditional examination by the trichinoscope, the modified digestion procedure using pepsin as a digestive fluid was successful. Moreover, it is suitable for detecting weakly infected swine. The importance of systematic examinations of all domestic and wild pigs became evident only recently in 1977, when in Bavaria an epidemic of trichinellosis occurred following the ingestion of undetected Trichinella containing wild pig meat. According to most recent knowledge on the cycle of development of sarcosporidia, the studies showed that the species Sarc. bovihominis and suihominis were pathogens for human beings. Quite apart from necessary supplementary examinations, the freezing procedure would here too, warrant an effective protection for the raw meat consuming population.

The microbiological and parasitic risks associated with the tremendous increase in the tourist traffic from West Germany and Austria into warmer countries are considerable even in the case of shorter stays, as has been confirmed by observations made on those returning from such areas. The most important groups of diseases -- worm diseases, amoebiasis, and malaria -- have maintained this ranking in Central and South America; in Africa, especially in the east, the incidence of malaria tropica is increasing. The proportions for Austria show that even numerically there are no great differences compared with West Germany. It seems that, as far as malaria is concerned, efficient prophylactic measures and reliable information are absent; at any rate, the cases of malaria tropica were severe and in the main no prophylactic measures had been taken. With the exception of Japan, the risk of hepatitis in all warmer countries and in the East in general is many times higher than in the Federal Republic of Germany and the length of stay is partly a determining factor. For instance, the risk of hepatitis is roughly forty times higher in India. All figures shown in this survey are supported by tables, literature, and personal experience.

Even after successful localization of dangerous epidemics, infectious diseases represent a troublesome accompaniment of growing tourism to warm countries. Classical pathogens of diarrhoea are subjected to a worldwide control network to prevent this disease at least from being spread. Close surveillance has shown that, additionally, less clearly defined pathogens exist which affect a high percentage of tourists and cause a usually harmless but nevertheless often very annoying diarrhoea. In a tropic insular state a field study was carried out with voluntary assistance of German flight passengers in order to investigate the qualitative and quanitative importance of travellers' diarrhoea and to supplement American observations mainly gained in Mexico. In a first study we found that pathogens were detected only in six out of 173 stool samples: the pathogens were Salmonellae which had caused clinical symptoms in two cases only. With respect to diarrhoea with different origin which affected some 20 per cent of our examinees we will inquire into the importance of E. coli as pathogen, which is generally classified harmless but liable to interfere considerably with holidays and recreation.

The extreme chemical heterogeneity of antimicrobial inhibitors may be compared with the large heterogeneity of the sites of attack. From the host of questions regarding the mechanism of action three problems are selected at random for discussion: 1. Penetration or transport of inhibitors into the cell. At least some of the inhibitors must penetrate into the cell and find their way to very specific points of action; and it does not go without saying that the antibiotics reach their targets without previously reacting with other cell components or without being "trapped" by the cytoplasmic membrane. In some instances an active transport, i.e. a "misuse" by antibiotics of a transport system for a substrate can be demonstrated. 2. Distribution of the targets in the cell. Distribution of the inhibitors over the possible targets is not uniform. The question why this is so remains unanswered. 3. The membrane as the point of attack for inhibitors. The probability that an inhibitor has a bactericidal effect also on resting cells is greatest with substances that act on the membrane. The question as to the function of the antibiotics for the active cell arises and the "defence function" of the antibiotics is called in question.

The primary process in the cleaning of hard surfaces is the adsorption of the active substance of the detergent at the interfaces: liquid/gas, liquid/liquid, liquid/solid. This primary step in the cleaning process induces secondary processes which in turn are responsible for the soil removal from the surface of the substrate. The first requirement for a cleaning effect is that the dirt and the substrate be well wetted by the cleaning solution as a result of a reduction in surface tension and of the adsorption at the solid/liquid interface. The further secondary processes which effect the removal of dirt vary considerably, depending on the type of dirt (e.g. oils, pigments). In the case of oily and greasy dirt, rolling-up penetration, formation of mixed phases, emulsification and solubilization are of importance. For pigments, the surface pressure of the adsorption layer and the electrostatic repulsion are the determining factors. The processes of pigment dispersion, emulsification and solubilization are, in addition, extremely important for the stabilization of the dirty wash bath and the prevention of deposits on the substrate. The essential active substances of the detergents are surfactant and complexing agents, the first being unspecifically adsorbed by hydrophobic interactions, and the latter specifically by polar interactions. They influence one another mutually and are responsible for an optimal cleaning effect when they occur in suitable mixing ratios; the special constitutional characteristics of the individual surfactant and complexing agents, must also be considered.