Emergence of a genomic variant of the recombinant 2k/1b strain during a mixed Hepatitis C infection: a case report.

To date, few natural intergenotypic recombinant hepatitis C virus (HCV) strains have been characterized. A recombinant strain 2k/1b was detected for one HCV RNA-positive individual who had just completed therapy for HCV 3a genotype infection. In the present report, five serum samples collected over the pre- and post-treatment periods were used to investigate all the present HCV strains and the change over time of the infection pattern. Interestingly, the 2k/1b strain was already present during the genotype 3a infection and persisted during treatment. In the specimen collected three months post-treatment, two distinct strains, 2k/1b and type 1, were found and then one 2k/1b strain in the subsequent ones. A genomic variant of the HCV RF1_2k/1b strain was identified. It was part of a mixed HCV infection and persisted and re-emerge after eradication of the dominant subtype 3a. This case indicates that HCV co-infection screening after relapse should be an alternative to explain the lack of response to treatment and the necessity to carefully study the epidemic spreading of this recombinant strain.