[New R-plasmids in strains of Serratia marcescens with multiple drug resistance]. / Novye R-plazmidy u shtammov Serratia marcescens s mnozhestvennoi lekarstvennoi rezistentnost'iu.

In 4 S. marcescens polyresistant strains isolated from patients conjugative plasmids transferred to Escherichia coli have been detected. Two of these strains carry each one plasmid which codes resistance to 10 different antibiotics, including aminoglycosides which rarely occur in our country, and belongs to group IncC. The third strain is the host of 2 plasmids. One of them is similar to the above-mentioned 2 plasmids with respect to the incompatibility group and a set of markers, but additionally codes resistance to cephalosporins; the second plasmid has been determined as belonging to group IncM, unstable and capable of rendering the cells highly resistant only to aminoglycosides. And, finally, the fourth strain also carries 2 plasmids: one of them is unstable and belongs, supposedly, to group IncI alpha, and the second plasmid is stable and belongs to group IncM. The plasmid of group IncI alpha differs from all other plasmids of our Serratia by its capacity of rendering the cells highly resistant to chloramphenicol.

[Transfer to Escherichia coli of the mercury markers of new Pseudomonas aeruginosa plasmids]. / Peredacha kishechnoi palochke rtutnykh markerov novykh plazmid Pseudomonas aeruginosa.

A total of 5 new conjugative plasmids pLD can be transferred from one Ps. aeruginosa strain to other strains of this species, but not to E. coli. Only the markers of resistance to mercury can be transferred to E. coli by means of plasmids Inc P-1. The present work contains the data confirming that the mercury markers of 2 plasmids pLD 1017 and pLD 1051 behave similarly to transposons.

[Pyocin production by bacillus pyocyaneus and sensitivity of strains of different origin to them]. / Produktsiia piotsinov sinegoínoí palochkoi i chuvstvitel'nost'k nim shtammov raznogo proiskhozhdeniia.

Using the method proposed by Gillies and Govan and their indicator strains, 342 P. aeruginosa strains isolated from the patients were studied in respect to their pyocinogenicity and typed according to the production of different types of pyocins. Besides, in 206 cultures the pyocin sensitivity of 16 standard P. aeruginosa strains (5 strains obtained from Govan and 11 strains provided by the authors) was determined. All the tested cultures fell into 23 pyocin types; of these, types I and X occured most frequently, 56 strains identified by means of indicators could not be typed due to the fact that the corresponding pyocin types were absent in Govan's scheme. The cultures isolated from the patients and the environmental objects during the outbreak of P. aeruginosa in a hospital were proved to belong to the same pyocin type (III). The double typing of the cultures, according to pyocin production and pyocin sensitivity, allowed to determine individual characteristics of 75% of the tested cultures.