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Biomedical subjects

M Rotter

Publications and source records attributed to M Rotter.

At least 127 records · Page 7Linked to original sources

[Comparison of efficacy of 14 procedures for the hygienic disinfection of hands (author's transl)].

The efficacy of 14 procedures for the hygienic disinfection of hands mostly with commerical preparations was tested by a new experimental model developed at the Institute of Hygiene of the university Vienna (1,3). The disinfectant power was clearly dependent on the duration of treatment as well as on the kind of alcohol used in the preparation (n-Propanol better than iso-Propanol better than Ethanol). After one minute the efficacy of all preparations containing one of the three alcohols as active agent was well comparable to that of the standard procedure which according to our proposal (5) uses iso-Propanol 60% (ml/ml) for 1 minute. For preparations with n-Propanol as the main active agent (Satinazid and Sterillium) this was true even after treatment for a period as short as 0.5 min. In our opinion disinfecting detergents are out of place for hygienic disinfection of hands. One preparation representing this group (Versuchspräparat A) was far less effective than the standard procedure.

1-Propanol↗

[Depoteffect of benzathine-penicillin (author's transl)].

15 test persons received an injection of 2,400,000 units of benzathine penicillin. Serum levels were subsequently assayed, as well as the excretion of the antibiotic in the urine. The samples were stored in liquid-nitrogen between collection and examination. Each of the speciemens was tested 5 to 10 times and the results were ascertained by empirical evaluation of every single analysis. This assay showed the existence of mean levels above 0.036 I.U./ml in the serum and above 19.75 I.U./ml in the urine for the duration of 26 days. The evaluation of serum levels after the administration of antibiotics is difficult due to several sources of error. Reliable results can, therefore, be obtained only by examination at special institutes which possess experienced technical personnel. The establishment of reference laboratories for this purpose is suggested. The results of the study confirm the efficacy of one-shot treatment of the syphilis by administration of 2,400,000 to units of benzathine penicillin.

Delayed-Action Preparations↗

[Sensitivity of bacteria causing urinary tract infections towards terizidon (author's transl)].

In agar diffusion tests 2603 bacterial strains of species known to cause urinary tract infections were tested routinely in regard to their sensitivity towards Terizidon, a derivative of cycloserine. In order to relate the results which were obtained in terms of the diameter of the inhibiton zone, to the minimal inhibitory concentrations (MIC), 304 of these strains were tested additionally in agar dilution tests. The MICs of the other strains were estimated from the results of these tests. Since it is known that after the oral administration of 500 mg Terizidon the urine contains, on average, more than 128 mug/ml Terizidon for 12 hours and longer, it may be concluded from the results of this investigation that 75% of the strains of E. coli and Citrobacter, 45% of enterobacter, 40% of Proteus mirabilis and enterococci, 35% of the indole-positive Proteus strains and 30% of Pseudomonas aeruginosa would have been successfully attacked by Terizidon in the case or urinary tract infections. By contrast, Klebsiella must be reagarded as being completely resistant to this antibiotic. It follows that the administration of Terizidon is mainly indicated in the treatment of acute urinary tract infections with E. coli as the predominant causative agent.

Citrobacter↗

[Further experimental investigations on the therapy of gas gangrene with ozone and oxygen (author's transl)].

In continuation of a recently-published investigation on the effect of intramuscular injections of an ozone-oxygen mixture on experimental gas gangrene in the guinea pig, 2 additional experiments were performed in order to establish the efficacy of the therapy when given twice daily instead of only once. Futhermore, the effect of an analogous therapy was investigated with the use of pure oxygen. The ozone-oxygen therapy reduced the death rate from 100% in untreated control animals to 73.6 and 70.0%, respectively, in the 2 series of experiments. The median survival times were prolonged from 0.56 and 1.33 days to 5.50 and 6.66 days. The use of oxygen twice daily reduced the death rates significantly even further to 57.0 and 47.9%. With this therapy the median survival time was increased to 8 and more than 12 days. The differences in therapeutic effect of the 2 gases were not, however, statistically significant. On account of its simple applicability previous experiments on animals it is proposed that this therapy be employed also in cases of human gas gangrene. In addition, the bactericidal effect of CaCl2, as used in this experimental study, on vegetative forms of Clostridia is demonstrated.

Animals↗

[The patient as a source of bacteria in intensive care units: influence of antibiotics and tracheal intubation (author's transl)].

133 patients in an intensive care unit, who prior to admission had not shown any signs of bacterial infection and had not received antibiotic treatment, were assigned to two groups at random. One group received antibiotic prophylaxis with penicillins or cephalosporins (+Pat.), the other group did not receive antibiotics (-Pat.). Staph. aureus was the most frequent facultative pathogen in tracheal secretions and in the environment of "-Pat.". This organism was significantly more frequent in "-Pat." than in "+Pat." in both the tracheal secretions and the environment. Klebsiella spp. outnumbered all other species in "+Pat.". They were significantly more frequent in tracheal secretions of "+Pat." than of "-Pat.". In the first week of hospitalisation marked changes were seen in bacterial flora of tracheal secretions of "+Pat.". Colonization with grammnegative bacteria rose to nearly 100%, the frequency of Staph. aureus diminishing at the same time. Monitoring by contact cultures revealed that gramnegative rods were significantly more numerous in the environment of "+Pat." than of "-Pat.". Matching bacterial strains cultured from tracheal secretions and from the environment of the patients proved that "+Pat. spread significantly higher numbers of their gramnegative bacteria into the environment. The same is true of "-Pat." for Staph. aureus. Intubation had no noticeable effect on the degree of contamination of the surroundings with Staph. aureus. Gramnegative rods were significantly more frequent in tracheal secretions of patients with intubation than in patients without. The same trend was observed for environmental contamination. As the clinical results of this study have shown, antibiotic prophylaxis does not protect patients from infections to the extent expected. Patients, and particularly intubated patients, receiving antibiotic treatment have to be considered as sources of highly resistant gramnegative organisms.

Anti-Bacterial Agents↗

[Kinetics of the release of testbacteria from the artificially contaminated hand (author's transl)].

It is demonstrated that the release of testbacteria from the finger tips of artificially contaminated hands is influenced to a very small degree only by application of the finger tip method when compared to the effect of ablutions. Therefore, without apprehension of influencing the post-values this method may be employed in order to assess pre-values as required by the test-model of Rotter and Mittermayer (5) for the evaluation of procedures for the hygienic disinfection of hands. In addition, it can be shown directly that it is irrelevant for the number of bacteria released after a germ-reducing procedure, whether the finger tip-method has been used or not, preceedingly. In contrast, all technical variations that aim at the restitution of the supposed loss of testbacteria (like renewed contamination after the assessment of prevalues) change the postvalues measurably and must be avoided, therefore. Drying of bacterial suspensions on the hands, as after artificial contamination, reduces the release of viable testbacteria depending on the time. This effect is stronger on the palms than on the finger tips. The influence of handbrushes on the release of testbacteria with simultaneous useage of detergents compares well with the effect of an alcohol disinfection. However, this method is not suitable to eliminate pathogens safely.

Escherichia coli↗

[Comparative investigations on the efficacy of tap water, some detergents and ethanol on the transient flora of the hands (author's transl)].

The germ reducing efficacy of tap water, soap, pHisoHex, pHisoDerm and 70% ethanol was compared using the model of hands artificially contaminated with E. coli. Each of ten persons washed 1, 2 or 4 minutes. Reduction factors were calculated from pre- and post-values and were compared for each individual. After one minute the logarithms of the geometric means of the reduction factors amounted to 2,99, 3,23, 3,28, 3,61, 4,25 in the above used sequence (Table 2). After one minute the reductions came off more slowly and the slopes were linear and parallel as far as the mechanical germ reducing procedures are concerned (Fig. 2). In contrast, ethanol caused a steeper slope even after one minute wash. The strong reduction achieved by mechanical procedures (even with water for one minute 3 powers of ten were observed) demonstrates the high hygienic importance of hand washings for removal of the transient flora. Detergents like pHisoDerm produce further significantly higher reductions and seem to be more suitable than aggressive disinfectants for application in fields where bactericidal action is not imperative. The proposals for procedures aiming at disinfecting of the transient flora issued by the Austrian Society for Hygiene, Microbiology and Preventive Medicine require a reduction factor of at least 10(5) after two minutes hand wash. The results of this investigation show that this is practicable with ethanol and necessary, otherwise the bactericidal action would not be different from a mechanical removal of the transient flora.

Austria↗

[Comparative investigation on recovering bacteria from the artificially contaminated hand (author's tranls)].

A modification of the basin-procedure (PRICE), the plastic-bag-(GASCHEN), the fingertip-(SCHUMBURG) and the glass-cup-method (STORY) were compared in order to evaluate their efficiency to recover bacteria from the artificially contaminated hand. With all 4 methods there was a linear relation between the bacterial content of the contamination and the rinsing fluid in which the germs were collected from the hands (FIG. 1, Tab. 9). The number of recovered bacteria per ml, however, differed greatly with the method used. Without regard to the volumes of rinsing fluid and the size of the offered skin area, both differing with the metheod, the finger-tip-procedure yieleded the highest counts followed by the plastic-bag-, basin- and glass-cup-method (Fig. 1). Compensating the influence of the volume the three procedures first mentioned appeared equally effective (Fig. 2 and Tab. 11). It, however, has to be noticed that the finger-tip-method uses a skin area considerably smaller than the other two methods. The glass-cup-method was the least effective but used on the palm the recovery was still 10 times that of the yield of the back (Fig. 2). Because of its high efficacy, the better exploitation of the subungual spaces and because of its simplicity, the finger-tip-method seems to be the procedure best suited for recovering bacteria from the artificially contaminated hand.

Bacteria↗

[Thoughts upon the construction of requirements of disinfection procedures concerning contaminated hands - an analysis (author's transl)].

The construction of detailed test methods for the evaluation of disinfection procedures has primarily to be based upon requirements which have to be formulated in advance. A recently proposed test model is being discussed on the basis of 5 conceivable formulations of possible requirements. Essentially, they may be allotted to two types: the one implies the comparison of the disinfection procedure to be tested as against an hypothetical procedure. The other makes use of the simple comparison with a concrete standard procedure and is preferable to the first possibility for several reasons. The presented, mathematical formulations of the structure describing the proposed model represents a first approximation in order to permit the comparison of disinfection effects on the hands under assistance of probabilistic methods and eliminating other effects inherent ot a test method.

Disinfection↗