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E M Petrov

Publications and source records attributed to E M Petrov.

11 recordsLinked to original sources
PubMed1997

[Development of polymerase chain reaction-based test systems for detecting leptospira in polytypical leptospirosis foci].

Two highly sensitive test systems G and B, based on the polymerase chain reaction, were developed for indication of pathogenic Leptospira interrogans, including the serovariants appearing during outbreaks in polytypical foci of leptospirosis in the tropical zone of China. These test systems can be used for rapid diagnosis of leptospirosis in humans in foci with different etiological structure.

China↗
PubMed1979

Leptospires colonial variations.

Six of 12 relatively freshly isolated and museum strains representing serovars mozdok, monjakov, kazakhstanica I and patoc were heterogeneous in colonia morphology. Recloned colonial variants of one and the same heterogeneous population did not exhibit any differences in antigenic properties in cross reactions of microagglutination and absorption of agglutinins. Along with it among the clones with various colonial types of the two relatively freshly isolated strains of serovar mozdok distinctions in virulence (LD50) for hamsters were marked. Moreover for the clones one of them differences in the level of renal infection (ID50) and in morphology of the cells (hooked and straight) were found. In a solid Tween-80 albumin medium in populations of two colonial variants (serovars monjakov and kazakhstanica I) colonial mutants appeared without any changes in antigenic properties, virulence and cell morphology with frequency of 10-9-10-8 per one bacterium per one generation.

Antigens, Bacterial↗
PubMed1977

Potential variability of Leptospira serovars belonging to the same group.

3 clone strains of monjakov and pomona serovars were cultured with prolongation in a medium containing homologous immune sera. Separate subcultures were cloned in a solid medium, while isolated clones were typed in microagglutination test with whole and absorbed immune sera and in some cases in an absorption test. The results showed that the mutants of subcultures with the minimal and maximal time of contact with the immune serum turned out to differ greatly from each other in antigenic properties. While antigenic mutants of earlier subcultures were constantly connected with serovars of Pomona serogroup, mutants of subcultures adapted to immune serum were serologically more related to butembo serovar of Cynoptery serogroup. The results obtained showing potential variability of serovars belonging to Pomona serogroup could be significant from the viewpoint of classification and phylogeny of Leptospira.

Agglutination↗
PubMed1975

[Sensitivity of certain strains of pathogenic Leptospira to streptomycin, the nature of resistant variants and the frequency of their occurrence].

Streptomycin sensitivity of 112 Leptospira strains isolated from domestic and wild animals was studied. Independent of the isolation period and nature the strains proved to be highly sensitive to the antiobiotic (MIC 0.1 to 0.5 gamma/ml). On the example of a clone strain of Leptospira it was shown with a fluctuation test that streptomycin resistance occurred spontaneously. Frequency of the streptomycin resistant mutations was determined for 5 clone strains of L. interrogans. It was 10-9 to 10-7 per a Leptospira.

Animals↗
PubMedDate not supplied

[Gene diagnostics of acute persistent Leptospira infection].

The results of clinical trials carried out in different foci have demonstrated high diagnostic value of analysis made with the use of the polymerase chain reaction (PCR) at early stages of Leptospira infection caused by infective agents of the serogroups Grippotyphosa, Canicola and Icterohaemorrhagiae. The possibility of leptospiremia lasting considerably longer than heretofore believed to be possible, as well as the persistence of leptospires in the liquor of patients after the acute phase of the disease is over, i.e. during the early and late convalescence periods, has been shown. This is indicative of good prospects of using the PCR analysis not only for early rapid diagnostics of Leptospira infections, but also for controlling the course of the infection, for prognosticating early and late complications of the disease, as well the mechanisms of pathogenesis.

Acute Disease↗
PubMedDate not supplied

[A new methodological approach for leptospira persistence studies in case of mixed leptospirosis].

A new methodical approach for Leptospira persistence studies in case of mixed leptospirosis, based on the use of PCR test systems with different taxonomic specificity for the indication and identification of leptospires, was developed. Two PCR test systems (G and B) were used in experiments on BALB/c white mice to study patterns of the development of mixed infection caused by leptospires of serovar poi (genomospecies L. borgpeterseni) and grippotyphosa (genomospecies L. kirschneri). The conclusion was made of good prospects of this method application in studies on symbiotic relationships of leptospires both in vivo and in vitro.

Animals↗
PubMedDate not supplied

[Prevalence of the gene encoding the outer membrane lipoprotein LipL32 in leptospires of different taxons].

Primers flanking the fragment sized 677 bp have been constructed on the basis of nucleotide sequences of the gene encoding the outer membrane lipoprotein LipL32. PCR-analysis was used to reveal the prevalence of gene lipL32 among 73 Leptospiraceae family strains representing different genera and genomic species. The gene lipL32 appeared to be conservative across the pathogenic species. In contrast, it was not detected in the genome of nonpathogenic free-living leptospires. Thus the developed PCR test-system with primers LEP21/LEP22 may be efficiently used to differentiate these two distinct ecological groups of leptospires.

Animals↗