[Identification by enzyme immunoassay of escape mutants S143L and G145R of hepatitis B virus (Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus)].

INTRODUCTION: The achievement of the goal of the World Health Organization to eliminate viral hepatitis B by 2030 seems to be problematic partly due to the presence of escape mutants of its etiological agent, hepatitis B virus (HBV) (<i>Hepadnaviridae: Orthohepadnavirus: Hepatitis B virus</i>), that are spreading mainly in the risk groups. Specific routine diagnostic assays aimed at identification of HBV escape mutants do not exist.The study aimed the evaluation of the serological fingerprinting method adapted for routine detection of escape mutations in 143 and 145 aa positions of HBV surface antigen (HBsAg). MATERIAL AND METHODS: HBV DNA from 56 samples of HBsAg-positive blood sera obtained from donors, chronic HBsAg carriers and oncohematology patients has been sequenced. After the identification of mutations in HBsAg, the samples were tested in the enzyme-linked immunosorbent assay (ELISA) kit «Hepastrip-mutant-3K¼. RESULTS AND DISCUSSION: Escape mutations were detected mainly in patients with hematologic malignancies. Substitutions in 143 and 145 aa were found in 10.81% and in 8.11% of such patients, respectively. The G145R mutation was recognized using ELISA kit in almost all cases. The kit specifically recognized the S143L substitution in contrast to the S143T variant. The presence of neighbor mutation D144E can be assumed due to it special serological fingerprint. CONCLUSION: ELISA-based detection of escape mutations S143L, D144E and G145R can be used for routine diagnostics, especially in the risk groups. The diagnostic parameters of the kit can be refined in additional studies. This immunoassay and methodology are applicable for the development and quality control of vaccines against escape mutants.

[Molecular genetic methods of typing of the Bartonellae].

The primer systems for the PCR detection of four house-keeping genes of bartonellae in clinical material were developed and tested. The tactics of the species RFLP typing was also developed and tested. The scheme of the species RFLP typing of bartonellae was tested using as an example two strains for the first time isolated in Russia from patients with endocarditis and fever of uncertain origin. The results of the typing were supported by sequencing of the amplicons obtained. According to the sequencing the isolates were attributed to the sub species Bartonella vinsonii, subsp. arupensis. The necessity of molecular epidemiological analysis of bartonelloses in Russia was substantiated.

[Respiratory chlamydial infection in children with a complicated course of acute respiratory viral infections]. / Respiratornaia khlamidiinaia infektsiia u detei s oslozhnennym techeniem ostrykh respiratornykh virusnykh infektsii.

The role and influence of Chlamydia trachomatis on the development and course of acute respiratory virus infections (ARVI) in 130 children admitted to the hospital of the Research Institute of Children's Infections (St. Petersburg) was studied. The occurrence of respiratory Chlamydia infections in ARVI patients with an unfavorable premorbid background was 35-36%. The disease took its course simultaneously with the mixed infection of the respiratory tract with viruses, pneumococci and their associations with staphylococci and Haemophilus influenzae. Chlamydia infection in children had no influence on the character of the clinical manifestation of ARVI with the exception of the obstruction syndrome which was constantly observed in children with ARVI (p < 0.001).

[The ultrastructure of a new species of Chlamydia--Chlamydia pneumoniae]. / Ul'trastruktura novogo vida khlamidii--Chlamydia penumoniae.

The dynamic study of a new Chlamydia species, C. pneumoniae (strain TWAR, isolate TW-480), inoculated into the monolayer culture of cells L-929 was made 24, 48, 72 and 96 hours after inoculation. When compared with C. trachomatis and C. psittaci, C. pneumoniae were found to stand between these two species with respect to the morphology of their intracytoplasmic microcolonies (inclusions): they were round, almost bubble-like, but more densely packed with chlamydiae, surrounded by an undulate membrane, preserving its integrity until the late stages of their development cycle. In cells L-929 C. pneumoniae had a typical development cycle accompanied by the formation of vegetative and spore-like cells, reticular and elementary bodies, as well as intermediate cells, though this process was slower than in C. trachomatis and C. psittaci. Besides normal elementary bodies, many altered ones were formed in the process of the development of C. pneumoniae in cells L-929. Most of these alterations were similar to the process of bacterial L-transformation and could be regarded as the manifestation of chlamydial pathology related to the adaptation to new host cells.

Ultrastructure of Chlamydia pneumoniae in cell culture.

The electron microscopic appearance of Chlamydia pneumoniae elementary bodies with pear-shaped, loose outer membrane has been suggested as one criterion of its classification as a new chlamydial species. The study of the original strain TW 183 in LCL 929 and HL cells and a low-passage isolate of Kajaani-6 isolate in HL cells revealed spherical compact elementary bodies common to other chlamydia.

[The effect of tetracycline therapy on the laboratory indices of chlamydia infection in Reiter's disease (preliminary report)]. / Vliianie tetratsiklinoterapii na laboratornye pokazateli khlamidiinoi infektsii pri bolezni Reitera (predvaritel'noe soobshchenie).

The authors studied the effect of tetracycline therapy (short and long courses) on the indices of chlamydia infection (antigens and antibodies) in Reiter's urogenous disease. The concentration of tetracycline in the blood serum and synovial fluid when administered in a daily dose of 2.0 g (single dose 0.5 g) was determined. It has been established that tetracycline exerts an inhibitory effect on the chlamydia infection not in all the patients suffering from Reiter's disease despite sufficient concentration of the antibiotic in biological fluids (blood serum, synovial fluid). Prolonged courses of tetracycline therapy proved most effective.

[Characteristics of the immune status of female cattle breeders with chlamydia infections]. / Osobennosti immunogo statusa zhenshchin-zhivotnovodov s khlamidiinoi infektsiei.

Chlamydia urogenital infections cause significant changes in the immune status which can be regarded as immunopathologic disorders. Taking into account the wide prevalence of infections of this kind, particularly among female agriculture workers, as well as their pathogenicity and health-related consequences, Chlamydia Trachomatis cases must be properly revealed in women affected with inflammatory diseases of genitalia with subsequent etiotropic treatment.