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Biomedical subjects

G J Tuschewitzki

Publications and source records attributed to G J Tuschewitzki.

10 recordsLinked to original sources

In vitro investigations into the formation and dissolution of infection-induced catheter encrustations.

Encrustations are the most frequent complications occurring with indwelling catheters and urine drainage systems. The conditions for bacterial infections, using synthetic urine and controlled contamination by Proteus vulgaris, were standardised by using an in vitro model. Crystal deposits on catheters were analysed by infra-red spectroscopy and scanning electron microscopy. The main components of deposits in all investigations were struvite (MgNH4PO4.6H2O) 60-70% and carbonate apatite (Ca10(PO4,CO3)6 (OH,CO3)2) 30-40%. Investigations as to the quality and quantity of encrustations confirmed the analysis. Irrigation treatment was carried out with physiological saline solution and citric acid solution (Suby G) to study and quantify the dissolution of crystal deposits. Regular irrigation with citric solution resulted in a 70% dissolution of encrustations and ensured free flow as ascertained by measuring flow rates.

Animals

[Hygienic measures in endoscopy].

Risks of infection associated with endoscopy, sources of infection, relevant microorganisms (P. aeruginosa, Serratia, HIV, HB, Cryptosporidiosis), disinfection procedures and the steps of disinfection procedures and reasons for failing of disinfection procedures are discussed. Channel systems and rinsing solutions are relevant but until today underestimated sources of infection. In detail the contamination of the channel system in endoscopes, problems of good disinfection and the significance of mechanical cleaning are described. In cases of Pseudomonas aeruginosa infections after endoscopy an immediate investigation of the contamination of the endoscope and of rinsing solutions is necessary. Automatic disinfection systems are requested, because with such systems a higher security for patient and personal is achievable. A regular control of the efficacy of the disinfection process by a competent Hygiene-Institute is recommended.

Cross Infection

[Transmission of "barber's itch" by bathing?].

Pathogenic fungi find a favourable environment in baths for multiplication and distribution. So diseases caused by dermatophytes are often observed in connection with a visit of a bath. With regard to transmission of a "barber's itch" caused by fungi in consequence of the visit of a bath, there have still no results been published. Considering previous knowledge about epidemiology, mechanism of invasion, living, and multiplication of pathogenic fungi it seems unlikely that a transmission of the germs of "barber's itch" takes place due to the visit of a public bath. The expression "barber's itch" is not uniformly used; thus, if visitors make complaints about this affection, an etiological differentiation is required.

Arthrodermataceae

[Examination of sewage for nitrification inhibitors with the help of a simple and accessible bioassay].

The biotest presented permits the investigation of sewage as for the presence of nitrification-inhibiting substances. A waste-water sample has to be aerated together with activated sludge for 5 h. The concentration of ammonia and nitrate will be analysed at the beginning and the end of the test. The intensity of nitrification can be detected comparing the increase of nitrate in the sewage sample with a control. In order to verify the reliance of the test the effect of different parameters on the test system like pH, BOD of the sludge, content of ammonia, nitrite and nitrate and different sewage-relevant compounds were investigated. The biotest was successfully applied in order to find out the inhibition of nitrification in a communal purification plant. An emission of nitrification inhibiting substances was determined by screening of the supplies of the purification plant.

Ammonia

[Induction of a microbial colonization of the walls of copper pipes through which drinking water flows].

Bacterial colonization developed within one month on the surface of a copper pipe used for the transport of drinking water. No severe signs of corrosion could be detected within six weeks. Dividing cells and the formation of microcolonies indicated active metabolism and multiplication of the bacteria and not only a more or less passive adsorption on the copper from the bulk phase.

Bacteria

Experimental investigations on dissolution of incrustations on the surface of catheters.

On the basis of a standardized in vitro irrigation model, the incrustation behavior of catheters was investigated using collected urine with controlled contamination (Proteus, mirabilis). Irrigation treatment with a NaCl solution did not effectively reduce incrustation compared to the control experiment. On the other hand, incrustations were definitively prevented or existing crystal deposits were largely dissolved with a citrate solution of pH 4.0 (Suby G). Analytical investigations (infrared spectroscopy, scanning electron microscopy) of the deposits on the catheter revealed the presence of struvite (MgNH4PO4 x 6H2O), brushite (CaHPO4 x 2H2O) and carbonate apatite (Ca10[PO4] [CO3OH]6[OH]2).

Catheters, Indwelling

Influence of biofilms by chemical disinfectants and mechanical cleaning.

Water conducting systems in hospitals (endoscopes, nebulizers, tap water systems, dental units etc.) are often important reservoirs of conditional pathogens. The sanitation of those systems by in vitro efficient chemical disinfectants is very difficult. An explanation may be that microorganisms are growing in such systems in wall adhering biofilms wherein they are protected from biocides. A method for testing the efficacy of chemical disinfectants and mechanical cleaning is described under conditions which imitate those in natural systems. A criterion for the efficacy of sanitation procedure is not only the good disinfection result but also the removal of biofilms. The investigation showed that aldehydes, and peracetic acid can reduce multiplying microorganisms without disrupting the biofilm. A preparation on the basis of hydrogen peroxide showed good antimicrobial efficacy and a distinct reduction and influence of the biofilm. The best result was achieved by mechanical cleaning. The test model is simple and a supplement to the conventional in vitro laboratory test for the efficacy of sanitation procedures of water conducting systems.

Aldehydes

[Microbiology of ground water and drinking water].

Groundwater has been considered a safe source for drinking water protected against surface contamination. However, a number of reports about chemical and microbiological contamination have disproved this assumption. Besides hygienical monitoring, little is known about the microbiology of ground- and drinking water. The purpose of this paper is to give a review about the main fields of investigation concerning microbial activity in ground- and drinking-water-action. The hygienical relevant topics are: survival and transport of microorganisms, microbiological degradation of organic pollutants, turn-over of nitrogen compounds, oxidation and reduction of iron and manganese and development of methods for microbiological water examination.

Fresh Water