[The occurrence of Yersinia enterocolitica in sewage]. / Untersuchungen zum Vorkommen von Yersinia enterocolitica im Abwasser.

Using a modified cold enrichment procedure Yersinia spp. were detected in 90.6% out of 32 raw waste water samples obtained within one year from two municipal sewage treatment plants. Moreover Yersinia were isolated from 50% of 6 effluent samples. Altogether 118 Yersinia strains were isolated and typed biochemically and serologically. 69 out of these isolates belonged to Yersinia enterocolitica, 60 strains to biotype 1, and 9 to biotype 4, serotype 0:3, 8 strains Yersinia enterocolitica serotype 0:3, biotype 4, considered to be a causative agent in human enteritis, harboured an 48 MD plasmid. The remaining isolates were identified as Yersinia frederiksenii (24 strains), Yersinia intermedia (22 strains) and Yersinia kristensenii (3 strains). The frequency of the isolation of Y. enterocolitica serotype 0:3, biotype 4 from sewage showed the same seasonal dependence as known from strains of human origin. In contrast to this, such dependence could not be found among other serovars of Y. enterocolitica and related species.

[The occurrence of antibiotic resistant coliforms in the waste water of a water treatment plant]. / Das Vorkommen von antibiotikaresistenten Koliformen im Abwasser einer Kläranlage.

Colony counts and total coliforms of the investigated biological treatment plant were decreased by more than 90% on average. In activated sludge processes the colony counts increased, whereas total coliforms did not show significant differences between raw sewage and activated sludge processes. With regard to the antibiotics tetracycline, chloramphenicol, kanamycin and gentamicin raw sewage samples contained on average 10(3) antibiotic resistant coliforms/ml. From agar plates supplemented with antibiotics a total of 896 strains were characterized. Single resistant E. coli strains (29.3%) were isolated most frequently from agar plates supplemented with tetracycline. However, coliforms isolated from agar plates which were supplemented with chloramphenicol, kanamycin and gentamicin showed a prevalent resistance to 5 and 6 antibiotics tested. The variety of resistance patterns of gentamicin-resistant coliforms was determined by few plasmids encoding gentamicin resistance only.

[Occurrence of gentamicin-resistant coliforms in river water samples]. / Das Vorkommen gentamicinresistenter koliformer Bakterien in Flusswasserproben.

In river water samples 0.006...0.3% of total coliforms were detected as gentamicin resistant. Among gentamicin resistant coliforms most strains (86.5%) could be identified as Klebsiella. Most frequently a Gm-plasmid of about 150 Md was isolated harboring in Klebsiella oxytoca, K. pneumoniae and E. coli strains. All gentamicin resistant wild strains transferred the resistance to E. coli K-12. Most Klebsiella strains harbored several plasmids, R-plasmids and others. There were not any differences in plasmid profiles between sensitive and resistant strains.

[Comparative study of the detection of Pseudomonas aeruginosa in water]. / Vergleichende Untersuchungen zum Nachweis von Pseudomonas aeruginosa im Wasser.

In this report we examined quantitatively (MPN-procedure) various methods of isolating Ps. aeruginosa from surface waters. When comparing different media (malachitgreen broth, Preuss-broth, selenite broth, asparagine broth, malachitgreen/acetamide broth) the enrichments in malachitgreen and asparagine showed the highest isolation frequencies after an 48 h incubation time. In heavily polluted river water the results can be improved by a second enrichment step in acetamide broth. Dependent on the river water pollution 0...11,000 Ps. aeruginosa/l were detected. In waste water up to 2.4 X 10(6) Ps. aeruginosa/l were isolated. The results emphasize the significance of water as a reservoir and a source of distribution of Ps. aeruginosa in the environment.

[Occurrence of antibiotic-resistant klebsiellas in waste water]. / Das Vorkommen antibiotikaresistenter Klebsiellen im Abwasser.

The investigated oxidation pond treatment plant reduces the Klebsiellae content in average from 2.5 X 10(4)/ml in raw waste water to less than 10/ml in effluent. Most frequently K. pneumoniae was isolated (92.8%). From the raw waste water multiple resistant Klebsiellae were isolated continuously, including gentamicin and trimethoprim resistant strains which transfer their antibiotic resistance in 74.4% of all cases to E. coli K-12. In sterile raw waste water transfer frequencies were found ranging from 10(5) to 10(-7). In Klebsiella wild strains frequently several plasmids could be detected.