CONFIRMATION OF NOSOCOMIAL TRANSMISSION OF HEPATITIS-C VIRUS BY PHYLOGENETIC ANALYSIS OF THE NS5-B REGION

Four hepatitis C virus transmission chains at three dialysis units wer e disclosed by limited sequencing; three of these were disclosed by an alysis of the NS5-B region of the genome. Dialysis on the same shift a s that during which infected patients were dialyzed was the common fac tor for seven patients in two chains. Two nurses exposed to needle sti cks and their sources of infection constituted two other chains. The s trains of three chains belonged to subtype la and formed clusters with an intrachain variability of 0 to 6 nucleotides compared to 8 to 37 n ucleotides for unrelated strains within this subtype. The clusters wer e supported by bootstrap values ranging from 89 to 100%.