[Development and use of the assay for Legionella pneumophila detection based on fluorescent real-time/endpoint polymerase-chain reaction].

The aim of the work was to develop a PCR-based assay for detection of L. pneumophila and L. micdadei in environmental samples as well as in clinical samples from low respiratory tract and to assess its analytic characteristics. The assay was used during investigation of the outbreak developed in July 2007 in town Verkhnyaya Pyshma (Sverdlovsk region). Polymerase-chain reaction (PCR)with fluorescent detection,sequencing and cloning of DNA fragments were used. Developed assay based on the PCR with fluorescent real-time/ endpointdetection is able to detect L. pneumophila in clinical and environmental samples and to quantify amount of bacterial DNA in water. Specificity of analysis (100%) was assessed using the panel of bacterial strains and samples from healthy individuals. Analytic sensitivity of assay and quantitation limit was 1000 GU in 1 ml. Sensitivity of the assay of artificially contaminated biological samples was 1000 bacteria in 1 ml. During outbreak investigation L. pneumophila DNAwas detected in 4 lung samples from 4 fatal cases, from 1 of 2 sputum samples, 1 of 2 bronchoalveolar lavage samples with X-ray confirmed pneumonia. Legionella's DNA was found in samples from cooling towers, central hot water supply as well as from showerheads in apartments of 3 patients. Fountain and drinking water samples were PCR-negative. Specificity of PCR-positive results was confirmed by sequencing. Use of the assay during outbreak in- vestigation allowed to confirm the diagnosis in fatal cases and quickly identify the possible source of infection.

[Isolation and molecular characterization of the influenza virus A/H5N1 strains isolated during outbreak of avian influenza among birds in the European part of Russia in 2005: strain with ozeltamivir-resistance mutation was found].

Isolation and characterization of the influenza virus A/H5N1 strains, isolated from chicken in the Yandovka village (Tula Region) and from wild swan near the orifice of the Volga River that died during an outbreak of avian flu in autumn 2005, were carried out. Genetic and phylogenetic analyses were performed. The goals of the analysis were to determine possible geographical origin of the strain, genetic similarity of isolated strains to earlier sequenced isolates, epidemic potential, existence of pathogenicity markers, and resistance to antiviral drugs. It was shown that the isolated influenza virus belonged to highly pathogenic variants of China origin by a reassortment of viruses genotypes Z and V circulated in poultry and wild birds. A number of molecular markers of pathogenicity to gallinaceous birds and mammals were found out. Mutations in the hemagglutinin gene promoting potentially high rate of replication in humans as well as mutations causing the resistance to amantadine/rimantadine were not found. The strain isolated from wild swan had the mutation causing resistance to tamiflu/ozeltamivir.