Arboviruses in the Astrakhan region of Russia for 2018 season: The development of multiplex PCR assays and analysis of mosquitoes, ticks, and human blood sera.

The Astrakhan region of Russia is endemic for the number of arboviruses. In this paper, we describe the results of the detection of the list of neglected arboviruses in the Astrakhan region for the 2018 season. For the purpose of the study in-house PCR assays for detection of 18 arboviruses have been developed and validated using arboviruses obtained from Russian State Collection of Viruses. Pools of ticks (n = 463) and mosquitoes (n = 312) as well as 420 samples of human patients sera have been collected and analyzed. Using developed multiplex real-time PCR assays we were able to detect RNA of eight arboviruses (Crimean-Congo hemorrhagic fever virus, Dhori (Batken strain) virus, Batai virus, Tahyna virus, Uukuniemi virus, Inkoo virus, Sindbis virus and West Nile fever virus). All discovered viruses are capable of infecting humans causing fever and in some cases severe forms with hemorrhagic or neurologic symptoms. From PCR-positive samples, we were able to recover one isolate each of Dhori (Batken strain) virus and Crimean-Congo hemorrhagic fever virus which were further characterized by next-generation sequencing. The genomic sequences of identified Dhori (Batken strain) virus strain represent the most complete genome of Batken virus strain among previously reported.

Antibiofilm Activity of a Broad-Range Recombinant Endolysin LysECD7: In Vitro and In Vivo Study.

Surfaces of implanted medical devices are highly susceptible to biofilm formation. Bacteria in biofilms are embedded in a self-produced extracellular matrix that inhibits the penetration of antibiotics and significantly contributes to the mechanical stability of the colonizing community which leads to an increase in morbidity and mortality rate in clinical settings. Therefore, new antibiofilm approaches and substances are urgently needed. In this paper, we test the efficacy of a broad-range recombinant endolysin of the coliphage LysECD7 against forming and mature biofilms. We used a strong biofilm producer-Klebsiella pneumoniae Ts 141-14 clinical isolate. In vitro investigation of the antibacterial activity was performed using the standard biofilm assay in microtiter plates. We optimized the implantable diffusion chamber approach in order to reach strong biofilm formation in vivo avoiding severe consequences of the pathogen for the animals and to obtain a well-reproducible model of implant-associated infection. Endolysin LysECD7 significantly reduced the biofilm formation and was capable of degrading the preformed biofilm in vitro. The animal trials on the preformed biofilms confirmed these results. Overall, our results show that LysECD7 is a promising substance against clinically relevant biofilms.