Molecular characterization of human adenoviruses associated with respiratory infection in Turkey

Human adenoviruses (HAdVs) are responsible for various clinical diseases. Molecular epidemiological studies of respiratory HAdVs are limited in Turkey. To determine the main genotypes and epidemiological characteristics of HAdVs in patients with respiratory symptoms. HAdV PCR-positive extracts of nasal/nasopharyngeal specimens sent to the Turkish Public Health Institution from various cities of Turkey in 2015-2016 were investigated by seminested PCR. Partial sequence analysis of the hexon gene of HAdVs was performed. SPSSv.24.0 was used. A total of 23/68 (33.82%) HAdV-positive samples were amplified. Mastadenovirus B, C, D, and F were detected and mastadenovirus B (10/23; 43.5%) and C (10/23; 43.5%) were predominant strains. Interestingly, HAdV-F known to have gastrointestinal system tropism was detected in two patients with respiratory symptoms. HAdV-B3 was the most prevalent genotype (9/23; 39.1%). Also, HAdV-B7 is defined as a reemerging pathogen. It is noteworthy that there is a cluster of four HAdV-C strains showing a close paraphyletic relationship with HAdV-2/6 intertypic recombination. To our knowledge, this is the first study showing that HAdV-B7 reemerging pathogen circulating in patients with respiratory infections in our country. It is also necessary to emphasize that HAdV-2/6 recombinant strains were detected in this study for the first time in Turkey.