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

We used the autoradiographic method according to Quastler and Sherman to analyse alterations in the cell cycle under the influence of city smog extracts. Investigations were performed on logarithmically growing cultures of kidney and embryonic cells of the Syrian golden hamster. Low concentrations of city smog extracts (0.125 micrograms/ml Benzo(a)pyren-equivalent) induced a remarkable delay of cell entrance into DNA-synthesis. Furthermore a considerable prolongation of generation time and phase of DNA-synthesis was detected. The number of mitosis was strongly reduced. Already a doubling of concentration of city smog extract caused an almost complete breakdown of the cell cycle and a disappearing of mitosis for a time period of 10 hours. Our results strongly indicate that city smog extracts lead to a severe alteration of the molecular biology of the cell. Taking this in consideration, it can be assumed that a long term exposure of human beings to the city smog could induce an injury of health.

In a collaborative study on a new quantitative suspension test for the evaluation of the bactericidal activity of chemical disinfectants, three laboratories performed the in vitro test on a phenol and an aldehyde standard in the critical use dilutions using Staphylococcus aureus and Pseudomonas aeruginosa as test organisms. The most striking finding was that the means of the germidical effect of one laboratory were significant lower than those of both others. Nevertheless the dispersion of the results did not differ among the laboratories. The differences could not be attributed to the subculture technique followed, nor to the daily inconstancy of the bacterial suspension resistance. The only feature that could explain the difference was the assessment of the microbiological work in itself. It should be stated, however, that the variance of the germicidal-effect values were rather low for this kind of microbiological work, so that differences between laboratories were significant even if the absolute values differed less than 1 unit.

All organic peracids are capable of damaging enzymes of the microbial cell irreversibly by oxidation and can thus kill microbes. When using organic peracids as a disinfectant it is expedient to prepare them immediately prior to use. This is possible by employing mixtures in powder form of acid depots (anhydrides, amides, esters) and hydrogen peroxide depots which react together with water only at the time of preparing the solution to form a balanced system, the active complex proper, comprising organic peracid, organic acid, hydrogen peroxide and water.

In a poultry processing plant in northern Germany 1412 swabs were taken from poultry carcasses together with 608 swabs from the personnel. The broilers came from 22 different chicken farms. The swabs taken from the poultry and those taken from the personnel proved to be 35% and 48% Staph. aureus positive respectively. The swabs taken from the feathers and from the skin were staphylococcal positive at a higher level (47%) than the swabs taken from the cloaca (19%) and the throat (23%). Between 8% and 63% of the animals from the various chicken farms were Staph. aureus positive. The frequency of staphylococcal contamination increased during the course of slaughter. 57% of the swabs taken from the gloves and the hands and 42% from the aprons of the personnel were Staph. aureus positive. Some biochemical properties, the phage patterns, and the antibiotic resistance against oleandomycin, erythromycin, bacitracin, streptomycin, tetracyclin, penicillin, chloramphenicol, virginiamycin and flavomycin were determined from 445 poultry and 345 personnel Staph. aureus isolates. Only small differences could be established between both sources in this way. Only 20% of the personnel and 34% of the chicken strains were resistant to antibiotics. In the strains collected from personnel, penicillin-resistance predominated while the poultry isolates showed predominantly tetracyclin-resistance. Of all antibiotics applied nutritively in the chicken fattening, there was a higher resistance only against oleandomycin (11% of the poultry strains). Between the chicken farms there was a different frequency of resistance (0--68%). The source of the staphylococci could be determined for only some of the strains. Only 2.5% of the chicken isolates showed characteristics described in the literature to be "poultry-specific", whereas 37% of the personnel and 24% of the poultry isolates were shown to be "human-specific" strains. It seems that the vast majority of the staphylococci originated from the slaughterhouse personnel. The rest of the strains differed in varying combinations of their properties from the given species characteristics. Although Staph. aureus was brought into the slaughterhouse by the poultry, the contaminations of the final product seemed to originate mainly from human beings.

In the scope of our research about the antimicrobial activity of serveral chemicals a number of substituted benzaldehydes and benzylalcohols was investigated under standardized conditions following the method of DGHM (German Society of Hygiene and Microbiology) against bacteria, dermatophytes and moulds. The germicidal activity, demonstrated by the suspension test, is generally low except under special conditions (low or high pH-value). The germistatic activity, demonstrated by the MIC-test, is much higher than the germicidal effect (figs. 1--4). The relation structure-germistatic activity is discussed.

The survival times of Staph. aureus, Strept. faecalis, E. coli, Klebs. pneumoniae, Ser. marcescens and P. aeruginosa were found out on aluminium foil. It was examined whether there exists a dependence on the initial colony count and in mixed cultures a mutual influence of the several species of bacteria. The longest survival times were found among the grampositive cocci. Ser. marcescens and Klebs. pneumoniae could no more be indicated after 19 days in case of initial colony count of log 7.0/cm2; E. coli could no more be shown after 14 days. P. aeruginosa had the shortest survival time. The dependence on the initial colony count was ascertained in 3 different concentrations of bacteria. The highest concentrations showed the smallest reduction of cocci and the longest survival times of Enterobacteriaceae respectively. The middle and lowest initial colony counts showed quicker reduction or shorter survival times. Ser. marcescens was more resistant to drying than Klebs. pneumoniae. The quickest dying rates showed P. aeruginosa without any dependence on initial colony count. In mixed cultures with Staph. aureus or Strept. faecalis survival times of Enterobacteriaceae were longer; the same result gave Klebs. pneumoniae in culture together with Ser. marcescens. The following explanation might be possible: because of the drying resistance of grampositive cocci the total bacteria number in these mixed cultures after several days is higher than in monocultures of E. coli, Klebs. pneumoniae or Ser. marcescens. This protects the Enterobacteriaceae against external influences for a longer time. Therefore it is understandable that the effect increases with the length of duration. The same interpretation could apply to the mixed cultures of Klebs. pneumoniae/Ser. marcescens.

This paper deals with special conditions for testing the sporocidal effect of disinfectants. A method for the production of spore suspensions (Fig. 1) and the negative influence of heating to its resistance against disinfectants was described (Fig. 2). It was shown that spores of a non-virulent strain of Bac. anthracis could be used for this procedure (Fig. 3). In performing the suspension--and the germ-carrier test it was necessary to watch the effect of postinhibition and of inactivators. The application of 10 microliter disposible loops in the suspension-test was recommended. Since the test for the evaluation of the influence of organic matter on the results of disinfection was unreliable (Fig. 4), it was proposed to replace it by invention of a safety-factor. The germ-carrier test should be done with constant amounts of spores, dried to the surface under defined conditions. Exposition of germ-carriers to disinfectants should be done in a chamber with constant temperature and rel. humidity, since the results are strongly influenced by these factors (Fig. 5).

Using the suspension test the action of dibromoisocyanuric acid (DBI) and--for the purpose of a comparison--elemental chlorine and Chloramine-T on three different spore strains at pH 7.0 and room temperature has been investigated. DBI proved to be a desinfecting agent by which at a concentration of 0.01 M positive halogene (= 1.45 g DBI/I) in 15--60 minutes (depending on the spore strain) a reliable kill can be achieved. Although using elemental chlorine shorter kill rates have been obtained (Chloramine-T was without any effect) DBI shows some advantages which also suggest its use in practice. As possible reasons for the differing efficiency of the three investigated substances the equilibrium concentrations of the hydrolysis products (HOCl resp. HOBr) and diffusion effects are discussed.

Feeding domestic animals with mycelia, a by-product of vitamine production, gave rise to the side effect of markedly improved utilization of the fodder. This effect is not due to the vitamine and protein content but to the antibiotic content of this waste product. The nutritive effect was brought about by a larger number of different antibiotics in concentrations which were considerably lower than the therapeutically required doses. Therefore we speak, in this connection, of a nutritive addition of antibiotics to animal fodder. Since at the time of introducing this feeding method only the mutational resistance to antibiotics of pathogens was known and since the nutritive dosaging cannot select such therapeutically relevant degrees of resistance of the germs, no importance was attached to the development of the resistance and its effect on human medicine. However, during the last decade it has been found that the feeding of antibiotics is indeed capable of selecting the plasmidic resistance to antibiotics of the gram-negative intestinal bacteria in the faeces of the animals. For pigs, calves and hens--to quote only the most important animals--now contain a coliflora almost completely studded with R-factors. Owing to the transmissibility of the plasmids and the epidemiologically short path from animal to man, dangers emerge for the human medicine from this nutritive selection. Therefore the use of all antibiotics which select resistance plasmids, should be avoided in animal feed stuffs. It would be best, if antibiotics used in human medicine were not used in veterinary practice.

The NZO-Mice were used to study the influence of carbon monoxide and lead under the condition of diabetic metabolism. The animals treated with 80 ppm (COHb 10.81) showed significantly lower tolerance for glucose. Even after removing the burden of carbon monoxide for 50 days, the blood sugar level after glucose tolerance test remained in experimental animals significantly higher than in controls (20-min-value). The NZO-Mice after enteral lead exposition showed no significant changes of the condition of the diabetic metabolism after the glucose tolerance test. However, the NZO-Mice, compared to NMRI mice and rats, reached significantly higher level of blood sugar.