A phylogenetic analysis elucidating a case of patient-to-patient transmission of hepatitis C virus during surgery.

A phylogenetic hepatitis C virus (HCV) assay based on the core-Envelope 1 (C-E1) region was developed and used to elucidate a case of a patient-to-patient transmission. The index patient showed clinical symptoms of hepatitis seven weeks after surgery for hallux valgus under general anaesthesia. She progressed to a chronic persistent infection as indicated by positive HCV PCR results two years after surgery. Before her operation, a patient with HCV antibodies and positive HCV PCR had undergone surgery in the same room. There were two possibilities whereby the index patient could have been infected with hepatitis C, either through her work as a nurse or by transmission during surgery. By sequencing the 5' non-coding region PCR product, we found that both patients were infected with genotype 1a. Phylogenetic analysis with the variable C-E1 region suggested that the two patients clustered together with a bootstrap 100% in a tree with 75 sequence references. We further performed a phylogenetic analysis in this region with the genotype 1a reference sequences and an additional 25 genotype 1a sequences consecutively collected from Danish patients with HCV. The two patients still clustered together, supported by a high bootstrap 1000 value of 999. Homology analyses combined with the epidemiological findings indicate that the patient operated on in the same room before the index case was the most likely source of transmission. The mode of transmission could not be conclusively established, but a reusable part of the anaesthetic respiratory circuit is a possibility and a well known risk. Copyright 2000 The Hospital Infection Society.