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Biomedical subjects

K Botzenhart

Publications and source records attributed to K Botzenhart.

At least 91 records · Page 5Linked to original sources
PubMed1979

[Studies to investigate the ecological importance of the mass development of Hydrodictyon reticulatum in infiltration basins for drinking water. I. Metabolic products and their effect on various types of bacteria (author's transl)].

Cells of the green freshwater alga H. reticulatum, harvested from their natural habitat, were found to have antibacterial activity. The active substances seem to be lipophilic, because ethanol extracts were more effective, especially against Bac. subtilis, than water extracts (Table 4). The different effects of water extracts, which were tested after various dilution steps (Table 1--3) presume, that there must be a second active substance. We suppose, that it is correlated with chlorophyll derivatives. Culture filtrate from a strain, grown under laboratory conditions, was tested in the same way. Concentrated tenfold it was active against several grampositive strains of bacteria.

Bacteria↗
PubMed1979

[Microbial emission, immission and changes in the germ count in the cooling water during operation of wet cooling towers. IV. Communication: microbial immission in the vicinity of wet cooling towers (author's transl)].

From the emission rates of the bacterial cooling tower emission determined in field measurements (see Comm. II) the mortality rate of enterbacteria on soil, grass and solid surfaces and the mortality rate in the atmosphere taken from literature the immission rates and the long-term effect on microbial surface flora were calculated and compared with our own measurements. The values used in the calculations include large margins for error. The atmospheric germ counts determined by experiment were no higher than the calculated values; they fluctuated in terms of concentration between 20 KBE m-3 and 200 KBE m-3 in ranges which were measured in areas with little or no anthropogenic influences. The maximum long-term surface load which occurs under these assumptions is 2.3.10(5) KBE M-2. This relatively small additional load (approx. 10(-3%) would hardly be noticeable in a number of colonies of approximately 10(10) KBE m-2 normally occurring in soil and grass samples.

Enterobacteriaceae↗
PubMed1978

Experiences and problems in the disinfection of fibre endoscopes.

The problem of the disinfection of fibre endoscopes is to achieve a good efficiency together with easy handling. There is not yet a disinfectant which shows a sufficient germicidal effect after a short time of contact with the fibre endoscope and which is harmless to the patient and medical staff. This paper deals with a two-stage disinfecting procedure in which the instrument undergoes a short intermediate disinfection using polyvidoneiodine (Betaisodona) between two investigations and a main disinfection at the end of a series of investigations using glutardialdehyde (Cidex). The measures lead to a sufficient reduction of the number of germs. The importance of the disinfection of all parts of the endoscopes, especially the channels and the accessories (water bottles etc.) is pointed out.

Aldehydes↗
PubMed1978

[Comparative investigations on the efficiency of chlorine and ozone against bacteria and spores (author's transl)].

This paper is concerned with the measurement of first order rate constants for the death of bacteria by chlorine and ozone. While the first order conditions for chlorine were achieved with the aid of a new instrument which works basing on the polarographic principle this was attained for ozone under steady state conditions. Besides differences of species some different properties for both oxidants were found as far as their bactericidal efficiency is concerned. They are discussed in this paper.

Bacillus cereus↗
PubMed1978

[Hygienic requirements for the architectural-functional design of intensive care units (author's transl)].

Three standard variants of intensive care units are described. The hygienic-microbiological examinations of the patients' surrounding show in how fat architectural factors influence the propagation of germs responsible for nosocomial infections. The results are hygienic requirements concerning the architectural functional structure of intensive care units to facilitate the maintenance of anti- and asepsis for the nursing personal.

Facility Design and Construction↗
PubMed1978

[Criteria for the hygienic appraisal of intensive care units (author's transl)].

7 intensiv-care-units (I.U.C.) were compared by analysing the charts of 100 patients from each station. They showed remarkable differences concerning the diagnosis of admittance, age and other factors related to the risk of infection. Consequently, kind and number of intensive care related medical procedures, the use of antibiotics, the duration of the patients stay on the station and the death rate differed widely. Some criteria concerning the layout, personnel, organisation and therapy on I.C.U. are named, which are mainly related to the patients condition and to the thereby given risk of infection.

Burns↗
PubMed1978

[Wound contamination in conventionally air-conditioned operating rooms as compared to laminar-flow-operating-rooms (author's transl)].

Two operating rooms (OP K I, OP K II) with conventional air-conditioning and one operating room with horizontal laminar-flow-ventilation (TAVS) were compared by measurements of airborne microorganisms, settling microorganisms and wound contamination. In OP K I and OP K II the number of airborne colonie forming units (cfu) was about 8/m3 when the rooms were empty and between 70/m3 (OP K I) and 140/m3 (OP K II) during operations. The first air in the TAVS-OP contained less than 1 cfu/m3, downstream of the operating team up to 80 cfu/m3. The number of settling microorganisms at the wound site was about 13 cfu/100 cm2 h in OP K I and OP K II, and about 2 cfu/100 cm2 h in the TAVS OP. Wound swabs showed a contamination rate of 45% (OP K I) and 54% (OP K II) versus 31% under TAVS-conditions. The difference is statistically significant with p less than 0.05. Various other factors as e.g. the duration of exposition, traffic of persons into and out of the rooms and the fate of microorganisms after sedimentation into the wound are discussed. While the number of settling germs is growing in linear proportion to the duration of exposition, the number of wounds found contaminated does probably approach a steady state in dependence of sedimentation rate and die-off rate in the wound.

Air Conditioning↗
PubMed1977

[Filtration and irradiation of the dialysis fluid to prevent bacteriemia during hemodialysis (author's transl)].

For prevention of bacteriemia caused by contaminated dialysis fluid it is necessary to protect the dialysator by decontamination of the fluid immediately before entering the dialysator. Using filters with a pore size of 0.2 micrometer or 0.45 micrometer sterile samples of dialysis fluid could be obtained, but flow rate and pressure of the fluid could not be kept constant, when the resistance of the filter increased during use. With UV-lamps no problems concerning flow rate or pressure were encountered, but really satisfying results emerged only in laboratory experiments. This was due to causes which can be influenced by technical improvements of the irradiation unit, while the use of filters implies additional measures at the monitor unit to control flow rate and pressure. The success of the applied antimicrobial techniques should be monitored for not inducing a false conviction of safety.

Filtration↗
PubMed1977

[Hygienic risks associated with sanitary installations and medical equipment in hospitals (author's transl)].

The risk of transmission of nosocomial infections associated with technical installations in hospitals probably is not very important. The way of infection (e.g. airborne particles, droplets, fluids, fomites, contact with persons) must be considered and an estimation as to their importance should be tried. Transport systems and air-conditioning plants are discussed as possible transmitters of infectious particles by air and UV-radiation and air-locks in their role as preventive measures. Fluides which can allow a microbial growth are part of many sanitary installations and medical equipment. They may cause transmissions of great numbers of pathogenes to susceptible patients. In this context, ultrasonic inhalators, irrigators, dialysis equipment and faucet aerators are discussed. Concerning transmission by contact, bed-pan washers, endoscopes and anaesthetic tools are mentioned and finally the role of industrial procedures, the extent and function of which can't be supervised by the medical personn,el, must be submitted to adequate microbiological controls. Physicians should pronounce more clearly then before their interest in equipment which can easily be sterilized.

Air Conditioning↗
PubMed1976

[Control of cross infection in intensive care units].

Quantitative determinations of antibiotic susceptibility established that infections occurring in intensive care units were predominantly exogenous cross infections. The most frequently isolated strains were: Klebsiella, Enterobacteriaceae, Serratia marcescens and Proteus mirabilis. The majority of the strains showed multiple resistance. Despite adequate antibiotic therapy a number of patients died of the infection. Many of the methods of disinfection were found to be inadequate, especially as regarded washbasins, face flannels, ultrasound inhalers, respirators and other apparatus. The fact that many of the isolated strains are capable of multiplying in water is not receiving sufficient attention.

Air Microbiology↗
PubMed1976

[On the growth of various Enterobacteriaceae, Pseudomonas aeruginosa and Alkaligenes spec. in distilled water, de-ionized water, tap water, and mineral salt solution (author's transl)].

The behaviour of 12 strains of gram-negative bacteria was analysed in media having a low content of nutrients. Sterile tap water, de-ionized water, aqua bidestillata and mineral salt solution were used. It was found that Serratia marcescens, Pseudomonas aeruginosa, Enterobacter, Klebsiella and Citrobacter are those with the most frequently observed growth. In the mineral salt solution survived also Providencia, E. coli, Erwinia, Hafnia, and Alkaligenes and reached max. colony numbers of some 100000/ml. When the salts used were added stepwise potassium phosphate and especially magnesium sulfate showed a growth-promoting effect.

Alcaligenes↗
PubMed1976

[Clinical uses of ultraviolet light radiation].

The main use of ultraviolet light radiation in hospitals is for the disinfection of the air. A study was made of the disinfecting efficiency of indirect ultraviolet radiation (lifts, cleaning of bedding), direct irradiation of rooms overnight or after use, ultraviolet curtains (irradiation of the whole width of passages, doorways and entrances) and ultraviolet irradiation of the filter of air-conditioners. The results are analysed. With the exception of the barrier technique ultraviolet light irradiation did not substantially reduce the number of micro-organisms in the air. Knowledge of the limitations and side-effects of this technique, control of the intensity of ultraviolet irradiation and bacterial counts are regular intervals are some of the factors that determine the success of this mode of disinfection. Detailed studies of the acceptable upper limits of the number of micro-organisms in the air of hospital wards and operating theatres is of prime importance for evaluating the effectiveness of air-disinfection by ultraviolet light irradiation.

Air Microbiology↗
PubMed1976

[Colorimetric cleck of the working dilutions of disinfectants on an aldehyde and phenol basis (author's transl)].

The applicability of 2 colour reactions were tested for the monitoring of the working concentration of disinfectant solutions containing aldehyde or phenol. The red coloration of Schiff's acid solution (Schiff's reagent to aldehydes) can be used with limitations. The formation of a red dye by the reaction of phenols with 1-phenyl-2,3-dimethyl-4-amino-pyrazolone-(5) in the p-esence of alkali and potassium hexacyano-ferrate (III) is unequivocal and is not influenced by contaminations in the water. Evaluation is made in either case by comparison with standard dilutions of the respective commercially available preparation. The samplest procedure for this a visual colour comparison in test tubes with calibration spectrum. Pyrazolone dye can be analysed photometrically. Thus this colour reaction can be regarded as an analytic method of satisfactory accuracy. A frequent monitoring of the disinfectant concentrations by means of simple chemical procedures is expected to help limit the improper use of disinfectants and to check hospital infections.

Aldehydes↗