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Peroxyethane acid (POA) is capable of disrupting the ring of bacterial catalase and has a broad microbiocidal spectrum. Following application, POA degrades to acetic acid and peroxide. There are no residues and no resistance development. Because POA administration for bladder and wound lavage in human medicine produced positive results, the substance was tested for the treatment of cows with endometritis.After successful preliminary trials under clinical conditions, a comparative analysis using standard uterine treatments, focusing particularly on antibiotics, followed. A total of 3557 cows from large herds with chronic endometritis catarrhalis of varying degrees were included. A 0.2% POA solution was used. The effect was evaluated based on the reproductive data for each substance used.After POA use, equivalent or better results were achieved compared to antibiotic-treated cows. Histological and cytological examinations demonstrated a rapid and high regenerative ability of the endometrium after intrauterine POA instillation. POA induced an intensive phagocytosis beyond the 6th day of instillation.According to the results, POA may be used as an alternative to antibiotics to treat endometritis catarrhalis chronica in cows. Currently, no licensed product is available, which significantly restricts POA use. In view of the increasing problems associated with antibiotic resistance, the new approval of a corresponding POA pre - paration is justified.

White spot disease, caused by the protozoan parasite Ichthyophthirius multifiliis (I. multifiliis), invades nearly all fresh water fish species and causes huge economic losses. In Germany no protocide substance is legal for the treatment of I. multifilis. As an alternative substance the peracetic acid (PAA) was tested to treat the free invasive stage (theront) of the parasite. PAA concentrations of 0.3 ppm were able to kill all theronts in 120 min in our investigations. As a result of these investigations we recommend an interval-application of 0.3 to 0.5 ppm PAA for 30 to 150 min. This application should be prolonged for two life cycles of the parasite. Biotic parameters as e. g. fish species, and age as well as abiotic parameters as e. g. temperature, pH and organic load of the water could possibly influence the efficiency of the PAA application and should therefore be taken into account while picking the dosage and length of the PAA exposure.

White spot disease caused by the ciliate protozoan parasite Ichthyophthirius multifiliis (I. m.), is one of the most dangerous diseases in aquaculture and ornamental fish breeding worldwide. The parasite is characterized by three developmental stages: a reproductive tomont, an infective theront and a parasitic trophont. In sander (Sander lucioperca) breeding I. m. causes serious economic losses. After banning of the traditional therapeutic agent malachite green we have to face a state of emergency for the treatment of the ichthyophthiriasis in Germany. The peracetic acid (PAA), characterized by positive therapeutical properties, might close this gap. The purpose of our investigations was the determination of the toxicity of PES to juvenile sander as well as the evaluation of the therapeutic effectiveness of the substance to combat I. m. For juvenile sander (length 3 cm) we determined a 24-h-LC50 of 1.14 (0.97; 1.3) ppm PES. In two investigations PAA was applied in daily intervals of 0.5; 1, 3, 5 and 24 h and concentrations of 0.5; 1; 1.5 and 2 ppm to treat I.-m.-infection in sander. In test I all sander (length 9 cm) died as a result of the I.-m.-infection. However, the PAA exposed fish survived longer than the PES-free controls! This might be due to a disinfection of other pathogens by PAA. In test II, the fish (length 12 cm) were less infected than fish in test I. Four of six fish died in the group exposed with 2 ppm PAA for 24 hours. The abundance of I.-m.-trophonts was determined in mucus, fin and gill tissues of all fish. Significant differences could not be observed between test I and test II because of dissimilar: 1. exposure in time and concentration, 2. age and condition of the fish and 3. homogenity of the variances. Therefore, no therapy strategy was successful while fighting the parasitic trophonts protected by the overlaying fish tissues. We speculate that a successful therapy of I. m. with PAA is, as known e.g. for malachite green, only possible while fighting the free living stages theronts and tomonts. This will be part of our subsequent investigations.

We analysed the sporicidal effect of different concentrations of aqueous and alcoholic peracetic acid (PAA) solutions on anthrax spores in suspension and germ carrier tests. In activation of anthrax spores in suspension assays was achieved in less than 2 min using 1% PAA solution and in less than 3 min using 0.5% PAA solution, respectively. In contrast, in germ carrier as says, a test under practical conditions, spores on 38% of the germ carriers survived treatment with 1% PAA solution for 15 min. The use of PAA in 80% ethyl alcohol outclassed the sporicidal effect of aqueous PAA solutions in both suspension and germ carrier assays. Anthrax spores on 14% of germ carriers tested survived 30 min of treatment with a 1% aqueous PAA solution. In contrast anthrax spores were reliably inactivated under the same test procedure using a 1% alcoholic PAA solution for 30 min. The proven enhancement of the sporicidal effect of alcoholic PAA solutions should be kept in mind when using disinfectants in practice. In further surveys we will optimise the test conditions.

In allogeneic bone transplantation, the transmission of viral and non-viral infectious pathogens is the most severe undesirable concomitant phenomenon. The investigations published were examined regarding the inactivating capacity of inactivation procedures that are presently performed in bone banks (peracetic acid/ethanol, gamma irradiation, moist heat) against clinically relevant pathogens (aiming at a virus titer reduction of at least 4 log10 TCID50/ml or titer reduction of non-viral micro-organisms of at least 5 log10 cfu/ml). In the suspension experiments, treatment with peracetic acid/ethanol (peracetic acid 2%, ethanol 96%, aqua ad iniectabilia 2:1:1, 4 hours, 200 mbar, agitation) achieved a titer reduction of > 4 log10 already after 5 minutes for a number of viruses (PSR, PV, BVDV). HIV-2 was also inactivated within 5 minutes below the level of detection ( 4 log10 TCID50/ml was only reached after 4 hours. The results mentioned could be confirmed in the carrier test (contaminated spongiosa cuboids used as ‘worst case’ scenario). In the suspension experiment as well as in the carrier test, the HAV titer was reduced after 4 hours by only 3.7 log10 and 2.87 log10, respectively. The preceding step of defatting the spongiosa tissue by chloroform/ethanol was validated using cell-associated HAV and showed an HAV titer reduction of 7 log10. In the investigations regarding non-viral pathogens, all test organisms were completely inactivated by more than 5 log 10 steps (cfu/ml). Gamma irradiation was the second procedure examined. D10 values (irradiation dose required to reduce 90% of the pathogen titers by one log10 step) that were determined in inactivation kinetics experiments (irradiation conditions: –30°C, 60Co source) corresponded to data published so far. In order to provide for maximal safety, an irradiation dose of 34 kGy was recommended for allogeneic bone transplants using BPV and a diaphysis model from human femurs. The ‘Marburg bone bank system’ was the third procedure examined (thermal disinfection, guaranteed temperature of at least 82.5°C for a minimum of 15 min) using centrally contaminated human femoral heads. All viruses were completely inactivated and their titer reduced by more than 4 log10 steps. Vegetative bacteria and fungi were also completely inactivated (>= 6 log10 in the supernatant). As expected, spores and spore-forming pathogens were not sufficiently inactivated and not inactivated, respectively (titer reduction of less than 2 log10 cfu/ml). However, the latter group can be disregarded, since femoral heads are procured in the operation room under sterile conditions and the following production process rules out a secondary contamination with spores. It could be shown in the investigations presented that all three procedures examined guarantee an inactivation of the viruses investigated according to the recommendations by the senior federal authorities. The three treatment procedures offer additional biosafety by a comprehensive inactivation of non-viral pathogens.

Hydrogen peroxide is used in formulations to control biofouling and for disinfection purposes in technical water systems or in the medical field. In this work the efficiency of hydrogen peroxide in combination with silver- and iron ions and peracetic acid, respectively, was investigated mainly against bacteria in biofilms. Experiments were performed with pure cultures of the strain Pseudomonas aeruginosa and mixed populations of drinking water bacteria. In experiments with biofilms, grown in batch culture, it was detected that the presence of 150 mg/L hydrogen peroxide with a contact time of 24 h had neither a killing nor a detaching effect; also not with the addition of silver ions (150 µg/L). Only the addition of iron(II)ions enhanced the antimicrobial activity of hydrogen peroxide but did not influence the detachment of biofilms. The generation of hydroxyl radicals via the Fenton reaction has been proved. Biofilm bacteria always showed a higher resistance than planctonic bacteria of the batch culture. In the Annular Reactor, which was modified during this work, investigations concerning the long term treatment of biocides against biofilms as well as their resistance and regrowth were per-formed. Biofilms were grown in Annular Reactors and treated daily with the combination hydro-gen peroxide and peracetic acid over a period up to 42 days. The application of high concen-trations caused a decrease in microbial activity but no bacterial detachment. The maint enance of the dead cells on the surfaces causes a selection of single resistant organisms that can start to multiply and lead to regrowth in the test system. According to practical conditions also lower concentrations of the combination hydrogen per-oxide and peracetic acid were applied. Neither a killing nor a detaching effect was observed. It was shown that after the third biocide treatment hydrogen peroxide and peracetic acid, respec-tively, were consumed significantly; a possible explanation would be the adaptation by in-creasing the catalase activity. The direct investigation of the biofilms in the confocal laser scan-ning microscope showed a changing in the biofilm architecture caused by the biocide treat-ment. The treated biofilms seemed to be more aerated. That could have an positive effect on e.g. heat exchange systems where the tested biocides are applied. Finally the different methods for testing the efficiency of biocides were compared and evaluated concerning their relevance in practice. From the findings of this study it becomes clear that the methods for detection of the efficiency of biocides should be adapted to practical conditions. In addition to this, supplementary additional microscopic investigation can give useful on the effi-ciency of biocides against biofilms.

Seventy-five animals were investigated in an attempt to study the chronological process of response to vaginal irritation by application of disinfectants for endometritis therapy. Aqueous peracetic acid solutions and Lugol solution were used. Cows reacted to intrauterine application of disinfectant drugs with tail lifting, pressing and sometimes groaning as expression of pain. We tried to quantify this response by registration of these different signs longer than two hours after treatment. The responses are caused by reflux of solution from the uterus into the vagina. They were different and depending on reflux volume, used drugs and their concentration. In comparison to peracetic acid solutions, the application of Lugol with 0.5% iodine seemed to induce a more intensive response to application.

The method of application, the material properties of the disinfectant as well as the spacious circumstances decide about the effect of aerogeneous disinfection processes. Microbiological results and practical experiences clearly show that formaldehyde can be replaced by special formulations of peroxyacetic acid (PES) in the procedure of thermonebulization; on condition that a suitable technique is used. Perhaps the decay of agents but also defects in the distribution were results of a too high temperature of application. Characteristic foultry effects on the floor could be replaced by the help of Pulse-Jet-Instruments with a fog development below 80 degrees C. Beware of vaporizing PES-preparations exclusively by heat supply.

Histological investigations were made on uteri of 61 cattle (27 of them after intrauterine treatment). The response activated by 0.2% peracetic acid in the bovine endometrium was a primary inflammatory process, however, necrotising within clearly pronounced limits. Degenerative alterations were the major histological findings 35 minutes from application of 0.2% peracetic acid. They were recordable from the epithelium but at that point in time could easily affect the entire cellular stratum. Histopathological phenomena on the fourth day from application of 0.2% peracetic acid were clearly less strongly pronounced than on the third day. Histiocyte infiltrates of moderate and rarely high intensity reflected increased phagocytosis in the process of endometrial regeneration.

The experiments were performed using frosted glass as carrier with its surface being contaminated with whole blood containing Staphylococcus aureus as test organism. At the time of sampling, a heparin preparation was added to the blood to prevent premature coagulation. After addition of the staphylococci, coagulation was initiated by means of a heparin antagonist. 10, 25, 50, 100, and 150 microliters, respectively, of the blood were homogeneously spread on rectangular test areas of 10 x 20 mm. After the blood had coagulated, each of the test objects was placed in 15 ml of the solution (20 degrees C) containing the active ingredient tested for 60 min. After that, the test objects were removed from the disinfectant and, in order to inactivate any adhering active components, treated with a neutralizing solution of suitable composition. The number of viable germs (colony-forming units) was determined quantitatively. The blood samples were ground together with quartz sand. Aliquots of the diluted suspensions were mixed with molten agar medium. The plates then were incubated at 37 degrees C over a period of 14 days. The relative number of viable germs (N/No) per test object was calculated from the number of colonies. Plotting of the microbicidal effects obtained (log N/No] versus the concentration of the active substance (see Figs. 1-3) yielded curves differing in some characteristics as e.g. curvature, slope of the lower curve section (log N/No). less than -3), concentration range according to the layer thickness of the contamination. To visualize the reduction of the efficacy of the respective disinfectants caused by blood, the concentrations of active components were determined which are necessary to achieve a microbicidal effect of log (N/No) = -4. These concentrations were plotted versus the amounts of blood per test area (Fig. 4). The resulting curve for formaldehyde was slightly U-shaped. With a raising amount of blood, the concentration required slightly decreased in the beginning and increased again from an amount of ca. 100 microliter blood per test area. For all other active substances, the required concentration of these substances increased with the amount of blood used. The curve obtained for ethanol exhibited the lowest slope. The slope of the curves increased in the following order: ethanol, m-cresol, peracetic acid, chloramine T, glutardialdehyde, benzyldimethyldodecylammoniumbromide. The curves for chloramine T and glutardialdehyde nearly paralleled each other.(ABSTRACT TRUNCATED AT 400 WORDS)

The results suggest a relatively favourable relation between minimum bactericidal concentration (enterococci) and toxic agent concentration (chicken embryos) of hydrogen peroxide in comparison with chlorhexidin-digluconate, sodium-tosylchloramide and peracetic acid. For chlorhexidin-digluconate a somewhat more favourable relation between minimum bacteriostatic and toxic concentration of the agent was established.

Official methods concerning the examination of sporocidal effects of disinfectants are presently lacking in the Federal Republic of Germany. Spore resistance of selected clostridial species towards formaldehyde and peracetic acid was examined by suspension tests and germ-carrier tests in comparison to spores of Bacillus cereus. Formaldehyde in concentrations between 5% and 20% as well as peracetic acid in concentrations between .004% and .125% were tested. Spore concentration of 10(6) spores/ml in the suspension-tests and 10(4) spores/ml in the germ-carrier tests with wooden germ-carriers were used. Against formaldehyde spores of Cl. septicum had the lowest resistance in the suspension tests followed by Cl. difficile, Cl. tertium, Cl. bifermentans and Cl. perfringens. Cl. sporogenes strain NCTC 532 had the most resistant spores. Concerning peracetic acid the situation was nearly the same. The resistance of all spores of pathogenic species under investigation towards chemical disinfectants was covered by those of Cl. sporogenes NCTC 532 treated with isopropanol. Isopropanol treated spores of B. cereus offer an alternative solution for practical disinfectant testing because spore production as well as growth of clostridia entail great expense. In order to cover the resistance of spores of Cl. perfringens A, the most resistant pathogenic clostridial species tested here, increased spore concentrations of B. cereus would be necessary.

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.

Vessels implants as possible vessel connections for chronic haemodialysis have to meet certain requirements concerning resistance to cutting and kinking and ability to be sewn under tolerable intraoperative damage risk. Preservation in peroxyethanic acid significant reduces the mechanical resistance of the biological primary material; by contrast, preservation in methanal clearly raises the mechanical stability of the preparations.

For the improvement of the registration of data by assessment of mutagenic risk the analysis of sperm-head abnormalities have been rendered as a suitable at indirect evidence of mutagenic potency. The reproduction of the results is well. The sensitivity of the test is high. The quantitative evaluation of genotoxic effects is possible. By reason of comparatively low methodical expense the screening investigations of species mouse are suitable, before more expensive tests will be accomplished for the elucidation of the mutation type. At 35 day-long intraperitoneal application the double number of sperm head abnormalities was approximately induced through Wofasteril (dose refer to main agent peracetic acid 2.6 mg/kg bw/d) and about 1/3 through cyclophosphamide (dose 25 mg/kg bw/d). With a 50% reduction of Wofasteril dose the mutagenic threshold-concentration was too low. The phenolic disinfectant Wofasept caused only slight no significant increase of the rate of sperm-head abnormalities (doses refer to the content of compounds, for Chlorocresol 1.6 mg/kg bw/d, for Clorofen 0.7 mg/kg bw/d and for detergent 4.8 mg/kg bw/d).

Animal experimenters investigations on the influence of various solutions of peracetic acid on the epithelium of the urinary bladder were carried out on rabbits. The results of the experiments showed that solutions of peracetic acid up to 0.01% are tolerated nearly without any reaction also under extreme experimental conditions. Higher concentrations of active substances lead to considerable changes of the epithelium of the urinary bladder in form of partly focal, partly diffuse haemorrhagic necrotizing urocystitides. No differences were the result when the commercial 40 percent peracetic acid Wofasteril and a 20 percent peracetic acid without admixture of a stabilizer as primary solution were used. The possible application of peracetic acid as antiseptic for the mucous membrane is discussed.

In our experiments, peracetic acid--known in commerce as "Wolfasteril" was tested as a new and efficient disinfectant to disinfect sewage waters from rendering plants. Peracetic acid was used in experiments in concentration of 0.1 to 1.0% for 30 sec. to 60 min. As a comparative agent, 5% chloramine was used. Results obtained in preliminary and main experiments proved that peracetic acid is fully appropriate to disinfect biologically cleaned sewage waters in rendering plants. Sewage waters supplying the main stream has to pass mostly a short section after having left the water clarifier. Consequently, the concentration of 1% peracetic acid acting for 30 sec. is the optimum one. The recommendation of this application norm for peracetic acid in water clarifiers from rendering plants being at least suitable in controlling disasters.

M. tuberculosis is susceptible to peracetic acid as a Disinfectant. However, there is no unanimity how the transmission of Mycobacteriaceae can be prevented and which quantitative requirements are necessary for its action. In practical work protein-like substances and varying numbers of tubercle bacilli are important in the efficacy of sputum disinfection. The tuberculocide effect of peracetic acid is scarcely influenced by such admixtures or by the number of test organisms. A preliminary attempt for killing M. tuberculosis in sputum by means of peracetic acid was successful.

The sporocidal properties of peracetic acid (PAA) at defined concentrations were characterized by determination of decrease in PAA after addition of D-glucose, human albumin and suspensions of spores; concentration of PAA, which inactivates 10(6)-10(7) spores of Bacillus cereus, B. subtilis, B. megaterium and B. licheniformis within 10-30 min; inactivation constant k, decimal reduction time D and the sporocidal index (mg PAA X min X ml-1) at that concentration. In contrast to albumin, the spore suspension caused relatively little reduction of PAA concentration (less than 5% at the concentrations used). B. cereus, B. subtilis and B. megaterium had similar inactivation rates with k-values in the range of 0.368 and 0.541 min-1, D-values between 4.26 min and 6.26 min at 0.2 mg/ml PAA. B. lichenformis was much more resistant showing a k = 0.345 min-1 and D = 6.66 min at 3.0 mg/ml PAA. The sporocidal index of B. lichenformis was 180 mg X min X ml-1 while the three other species had sporocidal index-values of 7 mg X min X ml-1.

The development of peracidous disinfectants allows a disinfection, inactivating an incomparable large spectrum of microorganisms and showing special advantages of toxicology. There is no release of evaporable toxic substances into the air after disinfection with the exception of products based on peracetic acid. In this paper cell cultures are chosen as indicator for the toxicity of evaporable substances. It is shown that the cells were able to propagate in the presence of active oxygen containing disinfectants as well as in the blanc test. However, there was no propagation of cells in presence of formaldehyde, glutardialdehyde and peracetic acid.

Peracetic acid is more and more used for the purpose of air desinfections in rooms. The examinations of DWORSCHAK and LINDE encouraged us to use peracetic acid in the rooms of creches in presence of children systematically. The applied concentration of peracetic acid is 4.6 mg/m3. With these examinations it was intended to prove if it is possible to influence the morbidity of acute respiratory diseases. Under the choosed conditions no side effects are observed over a time of twenty weeks. Publications concerning cocarcinogetic activity of peroxy compounds induced us to make a preliminary stop in the application of peracetic acid in presence of children. The number of diseases specially of respiratory diseases in the time of the examinations was very small. That concerns the examination groups and those compared with these. But nevertheless it is to be seen that the morbidity in the groups with application of peracetic acid is 3.5% and in the others 11.20%. The differences are significant. If the results concerning cocarcinogetic activity of peroxy compounds will be shure it is to decide whether the room desinfections will be continued in presence of children or not.