[Features of metabolism of Klebsiella genus bacteria]. / Osobennosti metabolizma bakterii roda Klebsiella.

Some metabolic peculiarities of bacteria of the genus Klebsiella were investigated. The bacteria under study were isolated from different sources and varied in virulence. The pathogenic and saprotrophic enterobacteria were discriminated based on their response to the addition of carbohydrates or nitrate to the medium. Pathogenic Klebsiella spp. exhibited mainly the mixed formic-acid type of fermentation and were more resistant to nitrates than saprotrophic bacteria with the butanediol type of fermentation. The bacteria Klebsiella pneumoniae subsp. pneumoniae isolated from different sources, such as patients, healthy persons, or the environment, exhibited no substantial differences in metabolism and virulence. It was inferred that these bacteria themselves cannot cause disease, and their isolation in morbid states is an indirect result of dysbacteriosis.

[The biological characteristics of Shigella flexneri strains circulating in Saint Petersburg in 1992-1994]. / Biologicheskaia kharakteristika shtammov Shigella flexneri, tsirkulirovavshikh v Sankt-Peterburge v 1992--1994 gg.

S.flexneri 2a strains isolated in 1992-1994 from 371 patients in sporadic cases, from 90 patients and their contacts in cases of group diseases and from 71 lethal cases of Flexner's dysentery, were studied in comparison with strains isolated in 1980s. The study revealed the biological heterogeneity of S.flexneri 2a strains. The circulation of 3 enzymatic variants and 11 variants differing in their sensitivity to colicins from Frederick's collection was established. The overwhelming majority of strains circulating in 1990s were resistant to 6-7 antibiotics, while the strains isolated in 1980s were resistant only to 4 of these antibiotics. The strains under study possessed antilysozyme activity, as well as pronounced invasive properties. The circulation of the population of multiresistant strains in the city could affect the course of present-day Flexner's dysentery and their domination in the ecological structure of Shigella infections.

[The pathogenicity factors in different representatives of the genus Citrobacter]. / Izuchenie faktorov patogennosti u razlichnykh predstavitelei roda Citrobacter.

No trustworthy distinctions were revealed under the comparative analysis of properties of bacteria of Citrobacter genus from 3 studied ecological groups (from patients with diarrhea, from healthy persons and patients with extraenteric pathological process). It allows the finding of potentially partogenic bacteria of Citrobacter genus in patients with diarrhea to be considered the manifestation of dysbacteriosis.

[The physiological-biochemical properties of Klebsiella pneumoniae strains of different origins]. / Fiziologo-biokhimicheskie svoistva shtammov Klebsiella pneumoniae razlichnogo proiskhozhdeniia.

While comparatively analyzing the properties of Klebsiella pneumoniae from three studied sources (patients, healthy people, environment), no reliable differences between the comparable strains have been revealed. No differences have been found in the toxin formation, hemagglutinating and antilysozymic activity, adhesivity and invasive properties as well as in the peculiarities of gas exchange, while growing on media with different nitrogen and carbon sources. The studied microorganisms differed only in antibiotic resistance: strains isolated from the environment were sensitive to antibiotics, whereas strains of human origin were resistant to them.

[Action of the lactoperoxidase system on Salmonellae and Shigellae]. / Deistvie sistemy laktoperoksidazy na sal'monelly i shigelly.

In vitro experiments have demonstrated that the lactoperoxidase system produces a bactericidal effect on salmonellae and shigellae. The physiological concentrations of the components of this system, making it possible to obtain a pronounced bactericidal effect, have been established. Lactobacilli have been shown to potentiate the effect of the lactoperoxidase system. The possibility of realizing the bactericidal properties of the lactoperoxidase system with respect to salmonellae and shigellae in the preparations of immune lactosera, intended for passive enteral immunization against intestinal infections, has been suggested.