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

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-patie nt transmission. The index patient show ed clinical symptoms of hepatitis s even weeks after surgery for hallux valgus under general anaesthesia. She p rogressed to a chronic persistent infection as indicated by positive HCV PC R results two years after surgery. Before her operation, a patient with HCV : antibodies and positive HCV PCR had undergone surgery in the same room. T here were two possibilities whereby the index patient could have been infec ted 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 foun d that both patients a ere infected with genotype 1a. Phylogenetic analysis with the variable C-E1 region suggested that the two patients clustered to gether with a bootstrap 100% in a tree with 75 sequence references. We furt her performed a phylogenetic analysis in this region with the genotype la r eference sequences and an additional 25 genotype la sequences consecutively collected from Danish patients with HCT: The two patients still clustered together, supported by a high bootstrap 1000 value of 999. Homorogy analyse s combined with the epidemiological findings indicate that the patient oper ated on in the same room before the index case was the most likely source o f transmission. The mode of transmission could not be conclusively establis hed, but a reusable part of the anaesthetic respiratory circuit is a possib ility and a well known risk. (C) 2000 The Hospital Infection Society.