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A number of germ carriers have been tested quantitatively, in order to select the optimum germ carrier for future quantitative tests of chemical disinfectants, belonging to the class of surface and instrument disinfectants. Quality criteria applied were the storage capacity of the carrier and the germ recovery fraction. For the surface disinfectant, the cotton piece was confirmed to be suited best, while for the instrument disinfection the mineralized soft rubber tube proved to be optimal. The cotton piece, however, stores ten times more germs than the rubber tube which means that with the former, reduction factors of as high as log 6 (-7) can be measured.

During a long term investigation (October 1986 October 1987) Yersinia spp. were isolated from sewage in 5 different stages of a sewage treatment plant in Kiel (Bülk), Schleswig-Holstein, FRG. Methods applied were MPN-procedure, cold enrichment in CIN-broth and finally incubation on CIN-agar (Cefsulodin-Irgasan-Novobiocin). Yersinia enterocolitica were specified according to their serotypes (O:3/O:9) and biotypes. Results (median/100 ml): sewage influent 90,000 KbE (log 4.95), aerated grit removal tank effluent 14.285 KbE (log 4.15), primary sedimentation tank effluent 20.000 KbE (log 4.30), activated sludge tank effluent 6.000 KbE (log 3.77) and final clarification effluent 260 KbE (log 2.41). After the final clarification a reduction of 99.72% was achieved. A general influence of the outward conditions (water temperature, proportion of oxygen, fecal and total coliforms, water flow, pH) on the behaviour on the Yersinia spp. could not be confirmed. The specification of the 644 germs isolated during the year showed an average proportion of 48.44% Yersinia frederiksenii, 29.5% Yersinia enterocolitica biotype 1, 18.94% Yersinia enterocolitica biotype 2, 2.8% Yersinia intermedia and 0.32% Yersinia kristensenii. Only once a pathogenic Yersinia enterocolitica could be isolated (serotype O:9/biotype 2).

Unlabelled: The efficacy of a disinfectant can only be determined exactly, when quantitative as well as qualitative tests are being performed. Aim of this study was to ascertain whether the earlier published method of a germ carrier test could be applied also to the testing of disinfectants for instruments. Rubber tubes of 1 cm length were used as germ carriers, Staph. aureus, Pseud. aerug., Proteus mir., E. coli and Cand. alb. as test organisms. The culture media were CASO-agar and -broth, latter containing 20% defibrinated sheep blood in some experiments. Two disinfectants on aldehyde-basis and one disinfectant on phenol-basis and on biguanide-basis, respectively, were used for the disinfectant tests. The rubber tubes were contaminated with bacterial suspension, dried upright on sterile filters and then put into 10 ml CASO-broth. After high speed vortexing of the germ carriers the bacterial count was determined. Following factors that were believed to probably having an influence on the recovery rate of bacteria were investigated: 1. the amount of fluid staying on the rubber tubes; 2. the drying time; 3. the vortexing time; 4. repeated vortexing; 5. variations of the initial concentration of bacteria on the rubber tubes; 6. addition of inactivating substances., Results: ad 1. The mean amount of fluid staying on the tubes was 0.0056 g. ad 2. Drying times longer than 30 to 60 min resulted partly in considerably lower bacterial counts. ad. 3. and 4. Neither extension of vortexing time nor repeated vortexing of the same germ carrier could raise the recovery rate of bacteria. ad 5. Higher initial concentration of bacteria on the rubber tubes could not be achieved. The recovery rate of bacteria was reliable even when the initial bacterial concentration was low. ad 6. Addition of inactivating substances to the CASO-broth had no influence on the recovery rate of bacteria. The test method was checked by testing four disinfectants for instruments and proved itself a good and reliable quantitative method.

Preoperative treatment with topically applied antibiotics does not always sufficiently reduce the bacterial flora of the conjunctival sac. Therefore, an additional disinfection procedure should be employed. Fifty-two eyes showing bacterial growth in the first conjunctical smear were treated with two drops of half-strength povidone-iodine solution (5%). Within 2 min 45 eyes showed an obvious reduction in bacteria; after an incubation time of 48 h, 26 eyes showed no bacterial growth at all. The colony counts of the remaining smears revealed a decrease factor of between 10 and 10(4). The average number of species was reduced from 2.15 to 0.63. To exclude the possibility that this was merely an irrigation effect caused by the povidone-iodine solution, 30 eyes were treated with two drops of NaCl solution and compared to the other groups. No significant decrease in colonies or species was observed. Povidone-iodine solution applied to more than 500 eyes undergoing vitreoretinal surgery caused no allergic reactions or corneal changes.

A highly evacuated wound drainage system according to Redon (980 mbar) was applied to 100 women who had undergone laparotomy. No change of bottles was necessary up to removal of the system in 96 cases. Bacteriological tests were applied to various points of the Redon system and revealed only minimum colonisation with pathogenic germs. No relationship was recordable between the rate of wound healing disorders and bacteria detected in the Redon system.

The occurrence and distribution of campylobacter spp. in the wastewater of a sewage treatment plant was examined from July 1985 to July 1986. The number of campylobacter was determined in a double set-up by the MPN-method. Preston broth and -agar containing FBP supplement were used as nutrient media. The samples were incubated at 37 degrees C and 42 degrees C, respectively. Subsequently 1345 isolated campylobacter strains were biotyped. The number of fecal and total coliforms, pH-value and temperature in the sewage were determined as auxiliary parameters. In addition to that data concerning air temperature and amount of sewage flow were available. The median-value of campylobacters in the inflow of the sewage treatment plant amounted to 3,7 X 10(3) cfu/100 ml. The following passage through the wastewater plant resulted in a campylobacter reduction of 99,5%. Distinctly more Campylobacter coli than Campylobacter jejuni could be isolated; Campylobacter laridis, fetus and Cephalothin-susceptible Campylobacter coli were to be found only occasionally. Probably due to toxic effects by the sewage the percentage of not totally biotypable, coccoid campylobacter increased during the clarification process. The number of campylobacters and their distribution was neither influenced by the auxiliary parameters nor by seasonal variations.

In a one-year-study wastewater from the sewage system of a big town was examined for the occurrence and distribution of campylobacter spp. The sewage consisted mainly of domestic and industrial wastewater, but also to a small degree of agricultural wastewater and abattoir effluent. Preston broth and agar were used as culture media. The number of campylobacter was determined parallel at 37 degrees C and 42 degrees C by the MPN-method. Three colonies of each agar plate were isolated and biotyped. The number of fecal and total coliforms, pH-value and water temperature were determined as auxiliary parameters. In addition to that meteorological data and data concerning the amount of wastewater flow were available. With exception of the abattoir effluent, which showed higher campylobacter counts, the number of campylobacter in the sewage system generally lay between 10(2) and 10(4) cfu/100 ml. Seasonal variations and influences by the auxiliary parameters could not be ascertained. The biotyping of 2391 campylobacter strains showed a prevalence of Campylobacter coli over Campylobacter jejuni. Campylobacter laridis, fetus and Cephalothin-susceptible Campylobacter coli could be isolated only occasionally. About 20% of the isolated campylobacters were coccoid and not biotypable.

A comparison was made of the Thran pressurized spray gun and scrubbing with cotton swabs on the removal of organisms from the skin. Both methods showed similar results but sometimes considerable differences in counts were found on adjacent skin areas. The cotton swab method was used to compare the effect of 60 or 70% isopropanol and 10% povidone-iodine on the flora of the outer side of the upper arm over 24 h. With the exception of one test person, no significant difference was found between the disinfectants.