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

The inactivating effect of anodic oxidation on viruses performed in an experimental electrolytic polarization unit was investigated with 11 different viruses suspended in tap and superficial water. Furthermore attempts were made to define the influence of factors important in experimental and water respect. Using concentrations up to 10(4) infectious units per ml representing a multiple quantity of the virus demonstrable in contaminated environmental waters all the viruses investigated could be inactivated reliably and rationally when suspended in tap water, more easily however in water of improved conductivity, by passing the current leading unit once. Anodic oxidation represents a fast and rational not denaturating method for decontamination of virus containing waters. Varying conditions of a water as well as bacterial contamination, so far remaining within naturally occurring scope, have only little or no influence on the inactivating effect on viruses. The applicability of the method is discussed briefly.

A city smog extract from an urban area inhibits the cell growth of hamster kidney cells in vitro. Parallel to an inhibition of cell multiplication a diminished rate of total DNA synthesis appeared. The number of cells in DNA synthesis is depressed in presence of city smog extract. These phenomena revealed a dose-response relationship. The biological effect of city smog extract is discussed.

Phenylmercuric borate (PHB) is very rapidly incorporated into the cells of Escherichia coli, and binds directly to its sites of fixation. The rapid incorporation of PHB probably results from the lipophilic character of the [phenylmercuric]+ cation. The distribution of PHB in the cell is fairly uniform if one compares with that of the proteins. This shows the low specificity of PHB with regard to proteins, all of which appear to be potential sites for fixation. However, from the structural point of view, PHB is more differentiated in its distribution. The cell wall of E. coli and the soluble cytoplasmic fraction do not constitute important sites of fixation. On the contrary, the cytoplasmic membrane appears to be a preferential site of fixation. Moreover, it is very probable that the distribution of PHB in vivo should be even more likely at the cytoplasmic membrane since the process of homogenization of the cells solubilizes a large part of the proteins associated to the membrane. On the membrane, an important part of PHB seems to be associated with the ribosomes and particularly to the ribosomal proteins.

The biochemical localization of phenylmercuric borate (PHB) on Escherichia coli shows that this disinfectant associates essentially with proteins. Protein electrophoresis demonstrates that each protein contains PHB, and that SH groups play a very important role in its fixation. The quantity of PHB able to associate with proteins is so large that many other electron donor groups must react with it. Moreover, it appears that concentration of PHB on cytoplasmic membrane results rather from the privileged position of this structure than from special physicochemical properties. The great reactivity of PHB towards proteins leads to numerous inhibitions and confers upon this antibacterial drug a very complex mode of action. Four important metabolic activities have been tested in the presence of PHB, namely: respiration, protein-synthesis, RNA synthesis and DNA synthesis. These four metabolic functions are rapidly and totally inhibited at low concentrations of PHB. The complexity of the mode of action of PHB makes the adaptation of bacteria to this disinfectant more difficult. In addition, in the case of plasmid dependent resistence, PHB, with its complexe mode of action, does not favour such a selection in opposition to the antibiotics which generally have a more specific mode of action.

Imported infectious diseases being seen more often in consequence of intensive human contacts with developing countries through labourers and tourists, but also in consequence of immigration and of import of exotic diseases and of food, favoured by the quick air traffic, can be divided into 5 groups: 1. Imported diseases from the tropics (exotic diseases) 2. Imported agents from the tropics with human infection in the native country 3. Re-importation of diseases which were eliminated in the homelands 4. Diseases which are as well imported as also native 5. Single disease importations from neighboured countries. The imported infections are discussed systematically, caused by viruses, rickettsias, bacteries, protozoes, fungi, and followed by references to statistics, laboratory infection reports, questions of insurance. Imported diseases of the future are especially mentioned. Knowledge of the tropical infections as a main danger for our "civilized" world should be part of the medical training, since imported infectious diseases cause an epidemiologic challenge in the modern picture of communicable infections.

As bacteriological examination of water often needs a longer time, it was tried to use chemical indicators for detecting sewage pollution of water. Such a chemical indicator is coprosterol, a sterin derivative, which is discharged from human and animal enteric systems. For epidemic evaluations, E. coli, normally not present in pure water, is a good fecal bacterial indicator. Wether there does exist a certain parallelity of the amount of coprosterol and the presence of E. coli, water from bankfiltration systems and coastal seawater were examined. The presence of E. coli was not in every case accompanied by a positive coprosterol test, so that epidemic evidence is not shown by the latter. Nevertheless, the test may be good to evaluate mixing procedures between two different kinds of sewage polluted water or between groundwater and surface water.

In the scope of our research about the antimicrobial activity of amin-aldehyde-condensates a number of partly new N,O-acetals was synthesized by reaction of formaldehyde with several alcohols and secondary amines. Structures and physically constants are shown in the tables 1 and 2. The antimicrobial activity is demonstrated by the results of the disk-test (table 3), of the minimal inhibition concentration (MIC, table 4) and the suspension and area disinfecting test following the methods of the DGHM (tables 5 and 6). It may be shown, that the N,O-acetals have both germistatic activity mainly versus Staphylococcus aureus, Bacillus subtilis, Aspergillus niger and Penicillium glaucum and germicidal activity versus the gram-negative testgerms especially Pseudomonas aeruginosa.

After the inoculation in the head region of sphagnum moss vegetation (Sph. magellancium-Erica Association and Sph. apiculatum-Eriophorum angustifolium Ass.) reach the mycobacteria the hyaline cells of Sphagnum (Fig. 1). The count of M. intracellulare serotyp Davis decreases rapidly already in three days after the inoculation of Sph. magellanicum Ass. and this trend in the course of incubation is being continued. In 27 days following the inoculation only 2 of 7 specimens contained a small amount of this mycobacteria (Tab. 2, Fig. 2). In the head region of Sph. apiculatum Ass. the mycobacterial count was more rapidly going down. Already 13 days after the inoculation only 2 of 7 specimens were found mycobacteria-positive; 24 days after the inoculation no mycobacteria were present (Tab. 3, Fig. 3). The elimination of M. avium from the head region of Sph. magellanicum Ass. follows within 13 days after the inoculation (Tab. 4, Fig. 4). For the microbial growth well predisponated hyaline cells with their porous cell wall and hollow spaces possess probably a mechanism, which is effective against microbial contamination of the productive head region of Sphagnum vegetation. Our further investigations have shown, that the growth of mycobacteria follows in the deeper, partially decomposed region of Sphagnum vegetation (KAZDA, 1978).

In suspension tests it could be found, that tyrothricin, isolated from bacteria, possesses an anti-infectious activity against Sendai virus. Concentrations of 10(2) to 10(3) ID50-units of Sendai virus were incubated with 0.5 and/or 1.0 mg tyrothricin per 5 ml for 30 minutes at 37 degrees C (pH 7.5). These mixtures were tested in embryonated eggs and showed a marked decrease of viral infectivity. Tween 80 added after the incubation period leads to an incomplete reactivation of the virus infectivity. According to these results and further preliminary studies on herpes simplex virus we suppose a virustatic effect of tyrothricin also in the case of other lipophilic viruses.