Zentralblatt fur Bakteriologie, Mikrobiologie und Hygiene. 1. Abt. Originale B, Hygiene最新文献

Studies were performed to test the effects of lead and cadmium on viability and phagocytic activity of human polymorphonuclear leukocytes (PMNL) in vitro. Viability was tested by dye exclusion test and leakage of lactate dehydrogenase (LDH), the phagocytic activity was assessed by counting of ingested yeasts (Saccharomyces cerevisiae) in 100 PMNL. It was demonstrated that the viability of human PMNL was only slightly decreased following 20 h incubation with the metals. This finding is in contrast to findings of studies with macrophages of rodents when viability was rather decreased especially by cadmium. However, both metals were found to markedly suppress phagocytic activity of human PMNL already following 30 min of preincubation with the metal salts. Thus, independent of effects on cell viability the defense mechanisms of human PMNL against infectious agents are markedly reduced in presence of lead or cadmium.

In a comparative study, the biological effects of different polycyclic aromatic hydrocarbons (PAH) on the fetal respiratory epithelium of Syrian golden hamsters were examined (light and scanning electron microscopy) in tracheal explants exposed in vitro to benz(a)anthracene (BaA), benz(a)acridine (BaAC), benzo(b)fluoranthene (BbF), benzo(e)pyrene (BeP), benzo(k)fluoranthene (BkF) and pyrene (PYR). Concentrations of the compounds related to the solubility in dimethylsulphoxide in the tissue culture medium (0.5% DMSO). Focally slight inhibition of epithelial differentiation and/or circumscribed simple metaplasia with an incidence of up to 10% were found in the controls (0.5% DMSO), BeP and PYR groups as well as in the explants exposed to low levels of BaA and BaAC. The frequency of these lesions increased with raising (doubling) the dose (50%: BaAC, BbF, BfK; 100%: BaA). Following exposure to the latter compounds a similar dose response relationship was observed for dysplastic alterations of the respiratory epithelium. In some of these cases (10%) the epithelial change was associated with focally hyperplastic and/or proliferative exophytic growth. Morphologically, the alterations were comparable to those representing early changes associated with the development of epidermoid and mucoepidermoid neoplasms found after in vivo PAH exposure. In terms of transformation, the data support the information obtained from observations on mixed fetal hamster lung cells exposed to the same compounds.

The noncompetitive Sandwich-ELISA (polystyrene balls) with labelled antibody for staphylococcal enterotoxins (SE) A, B, C, and D according to Fey et al. (1984), which have recently been introduced commercially, was applied to analysis of foods. The effect of various food ingredients on the quantitative determination and recovery of SE was investigated. The unspecific effect of food components which, in some cases, caused false-positive results in the competitive ELISA was less frequent. Nevertheless, the differences in binding of unlabeled antigen between buffer and food were still observed. Using ELISA microtiter plates the effect of food components was less pronounced. Enterotoxin type A or a mixture of A and D were dominant in foods which were involved in food poisoning (about 150 samples). In meat the recovery of SE added (1-10 ng/g) ranged from 30-60%. The assay sensitivity in buffer ranged from 0.1 ng/ml for enterotoxins A, B, C and D (5 ml sample) to 0.2 ng/ml for enterotoxins A-D (1 ml sample) using polystyrene balls and was 1 ng/ml for enterotoxins A-D using ELISA plates. In foods the detection limit was occasionally higher. The required sensitivity for enterotoxin A (maximum limit 1 ng/g) could mostly be reached. Because of the differences in antigen binding in buffer and in various food extracts the determination of the enterotoxin content in this range is laborious.

The phototoxic effects of polycyclic aromatic hydrocarbons (PAH) benzo(a)pyrene, benzo(a)anthrazene, indeno(1,2,3-cd)pyrene, fluoranthene and perylene, and their relation to the known carcinogenicity of these compounds was examined with human fibroblastic cultures. Using different light filters it could be demonstrated that phototoxic effects on the cell cultures only occur with wave lengths shorter than 400 nm, that is in the longwave UV-region. With wave lengths longer than 400 nm, that is in the visible region of light, no cytotoxic effects could be detected. Irradiated with long-wave UV, the highly cancerogenic compounds benzo(a)pyrene, and indeno(1,2,3-cd)pyrene proved to be highly cytotoxic, the moderately cancerogenic benzo(a)anthrazene turned out to be distintly cytotoxic, fluoranthene supposed to be not cancerogenic, proved to be only slightly cytotoxic. Perylene that is considered not cancerogenic either, reacted completely indifferent. These results are completely compatible with those obtained earlier with ciliata (unicellular protozoa). They confirm the assumption that the so-called ciliata test (Tetrahymena pyriformis) can be used as a practicable test system to ascertain the carcinogenicity of PAH.

The cadmium-concentration in blood of 89 mothers and their newborns of different bavarian areas were measured by atomic absorption spectrometry. The results are within the frame of comparable recent national and international studies. A median value of 0.8 microgram Cd/l blood for the mothers resp. 0.3 microgram Cd/l for the newborns was found. The measured values ranged between 0.2 and 4.5 micrograms Cd/l for the mothers resp. 0.2 and 1.2 microgram Cd/l for the newborns. The significant difference between the cadmium-concentration in the blood samples of mothers and newborns confirms the existence of a placental barrier for cadmium. However, there was a significant correlation between the values measured for the mothers and their children (rk = 0.436). For the division into the three sub-collectives of Marktredwitz/Oberfranken, Freyung/Niederbayern und Erlangen/Mittelfranken (median values 0.6, 0.9 and 0.8 microgram Cd/l blood respectively) no significant differences could be observed. The blood-cadmium-concentrations of mothers and their newborns were not influenced by the age of the mother. An effect of the duration of the pregnancy could not be stated definitely because of a too small number of mothers with a low duration of pregnancy. A significant relationship exists between the smoking habits and the maternal blood-cadmium-concentrations. When dividing into subgroups the non-smokers show a median value of 0.6 microgram Cd/l blood, whereas the smokers have a median value of 1.1 microgram Cd/l blood. There were no significant differences between the blood-cadmium-concentrations of the newborns of smoking and non-smoking mothers. The median values were 0.3 microgram Cd/l blood for the children of non-smoking mothers respectively 0.4 microgram Cd/l blood for those of smoking mothers.

The competitive ELISA (polystyrene balls) with labeled antigen according to Stiffler-Rosenberg and Fey (1978) was applied to the analysis of Staphylococcal enterotoxins (SE) A, B and C in food to see if the enterotoxin concentration corresponding to maximum limit for SEA and SEB (1 ng/g food and 10 ng/g food respectively) could be measured. The effect of various food ingredients on the quantitative determination of SE in single-step and two-step variants of competitive ELISA was investigated. Generally, the effect of food was the lowest in extracts of cheeses and the highest in extracts of meats and pasta products. All enterotoxins were equally affected. However, within the same type of food significant differences in binding of both labeled and unlabeled antigen were found. The effect of food components often depended on the assay variant; the extracts of cheese gave better results in the two-step and the extracts of pasta better results in the single-step ELISA. In some weak-positive extracts, false positive results could not be excluded. In the samples of cheese which were involved in food poisoning exclusively the enterotoxin type A was found (up to 30 ng/g). The recovery of added SE (1-10 ng/g food) ranged from 50-70% in cheese and was about 70% in pasta foods. The assay sensitivity in buffer ranged from 0.2 ng/ml for enterotoxins A and B and 0.3 ng/ml for enterotoxin C (20 ml sample) to 0.5 ng/ml for A and B and 0.6 ng/ml for C (5 ml sample) to 1 ng/ml for A and B and 2 ng/ml for C (1 ml sample). In food, especially in meat and pasta the detection limit was often higher. With some exceptions the required sensitivity for enterotoxin A (1 ng/g) could only be reached in cheese.

Samples of piped water were taken from the source of the springs in ten villages in Lorraine. Usually this water has not been subjected to disinfection. The water was tested for fecal indicator bacteria, phages and animal viruses. Of the ten samples examined, seven contained no fecal indicator bacteria, phages or animal viruses, in three samples, however, Reovirus type 2 was found. Among the three positive samples only one contained fecal bacteria and phages. Consequently, the two other samples could be regarded as drinking water, despite the presence of viruses. Such an approach poses the problem of testing drinking water for viruses and suggests that viral tests should be undertaken as part of the water quality control.

Microbiological investigations were made during a one year period on refuse from consulting rooms of general practitioners, E.N.T.-specialists, dermatologists, dentists, and veterinarians. Concentrations of total aerobic bacteria, hyphomycetes, yeasts, actinomycetes, indicator bacteria (Escherichia coli, feacal streptococci, anaerobic sulfite reducing spore-forming bacteria), of some facultative pathogenic bacteria (Pseudomonas aeruginosa, Staphylococcus aureus), and pathogens (Salmonella sp.) were estimated. The refuse from medical consulting rooms showed definitely differences in microbiological properties. Usually the highest counts of microorganisms were found in the refuse from veterinarian consulting rooms. In generally, refuse from medical consulting rooms had lower microbial counts as compared to the municipal refuse. Feacal indicators and facultative pathogenic bacteria, however, were found more frequently, and usually at higher concentrations in refuse from medical consulting rooms. Salmonella sp. was not found in the refuse samples under test. Conclusively, refuse from medical consulting rooms should be handled with caution. However, the results of this study do not indicate those kinds of refuse as a source of acute hygienic risk.

The effect of disinfection of knives with water of 82 degrees C (180 degrees F) strongly depends on the amounts of protein and fat present on the tools. When fats or proteins are absent, even a high bacterial contamination on a stainless steel plate will be completely eliminated by immersion in water of 82 degrees C during 1 s, whereas even after 10 s immersion does not give satisfactory results if a high degree of fat and protein contamination is present. By adding lactic acid to hot water the bactericidal effect may be improved, although the results are far from optimal. Apparently, optimal disinfection of contaminated knives is extremely difficult to attain without the use of mechanical forces such as a high pressure water jet to remove the dirt. Therefore a special disinfection unit was designed in which apart from the factors cleaning time and temperature, the effects of mechanical forces could be determined. By increasing water pressure the cleaning effect was improved. Adding lactic acid to the spraying water made it possible to lower water temperature and water pressure, which, among other things, resulted in a lower climatological strain at the place of work. The thermodisinfector (a modified dish-washer) appear to be a good alternative for cleaning and disinfection of tools if the requirement is dropped that every worker had to have a disinfection facility within his immediate reach. The practical application of such equipment is discussed.

A description of a casein-soya-lactose broth (CSLB) for the cultivation of chlorine-impaired E. coli bacteria is given. In this liquid medium the recovery rates of chlorine impaired E. coli are superior or at least equal to recovery rates observed when casein-soya-broth (CSB) is used. Differences are regularly seen when lactose-pepton-broth (LPB) according the German Standards (DEV.K6) is used between direct inoculation into a liquid enrichment medium and inoculation into the same medium following membrane filtration are no longer found when CSSL-broth is used instead of LPB.