Molecular evidence for nosocomial transmission of hepatitis C virus in a French hemodialysis unit

A systematic virological follow-up of hemodialysis patients identified 11 c ases of de novo hepatitis C virus (HCV) infection in the same unit that wer e not due to blood transfusion. There were three groups of infection, each occurring within a period of 3 months: four infections with genotype Ib, tw o infections with genotype Ib, and five infections, four with genotype la a nd one with genotype 5a. The possibility of patient-to-patient transmission was addressed by sequencing the first hypervariable region of the HCV geno me in sera taken shortly after infection. Phylogenetic analysis indicated c lustering of most of the cases of de novo infections. Sequence homologies i dentified potential contaminators among already infected patients. All pati ents who were infected with closely related HCV isolates were found to have been treated in the same area and during the same shift or on the previous one. These infections could have been due to occasional breaches of the us ual hygiene measures. Strict adhesion to hygiene standards and routines, co ntinuously supervised, remains the key rule in the management of dialysis p atients. Nevertheless, the isolation of patients with HCV could reduce the risk of infection because occasional lapses of preventive hygiene measures or unpredictable accidents can always take place in a hemodialysis unit. Th is policy needs to be evaluated by large-scale prospective studies. J. Med. Virol. 58:139-144, 1999. (C) 1999 Wiley-Liss, Inc.