Genotyping clinical cytomegalovirus isolates in solid-organs-transplant recipients

Abstract

Cytomegalovirus infection remains one of the leading problems in contemporary healthcare. It belongs to socially and economically significant infections with a high incidence both in children and adults, characterized by polymorphic clinical manifestations and a variety of routes and factors for infection transmission. CMV infection of blood and organ recipients is a serious problem. It should be noted that, despite the great medical and social significance, in the Russian Federation there is no system of CMV epidemiological surveillance and control as it was traditionally developed for other topical infections. The aim of this study is to search for optimal method of cytomegalovirus (CMV) genotyping and estimate genotypic diversity of CMV isolates in Russia for patients underwent solid organ transplantation. The research presents the data after examining blood samples, leukocytes, saliva, urine and lacrimal discharge collected from 160 patients at the Transplantation Department of the Privolzhsky District Medical Center of the FMBA, aged 22 to 64 years, after liver and kidney transplantation. Molecular biological and serological methods were used for testing. Genotyping was carried out by the NGS sequencing of CMV DNA fragments. A high prevalence of CMV was found in patients undergoing solid organ transplantation. For 41.8±3.8% patients, cytomegalovirus DNA was detected in saliva and urine samples, and for 18.1±3.04% of them — in blood samples. In 98.8±3.2% of patients, the diagnosis of Cytomegalovirus infection (CMVI) was confirmed serologically. Based on a summary of reported data, estimation of various methodological approaches for genotyping of clinical CMV isolates was carried out. As a result, a typing option based on genotype determining for two variable genes UL55 (gB) and UL73 (gN) was selected. The spectra and proportional distribution of gB and gN CMV genotypes circulating among adults were determined. It was found that genotype prevalence in the group of patients who underwent solid organ transplantation was as follows: gB2, gN4c, gN4a, gN1. In some cases, a mixed infection was found due to the association of two and three CMV genotypes. The performed phylogenetic analysis of UL55 and UL73 gene nucleotide sequences indicates the genetic heterogeneity found for Russia-wide CMV isolates from in adult patients in the risk group.