MOLECULAR EVIDENCE FOR NOSOCOMIAL SPREAD OF 2 DIFFERENT HEPATITIS-C VIRUS-STRAINS IN ONE HEMODIALYSIS UNIT

The highest prevalence of hepatitis C virus (HCV) infection among hemo dialysis patients in Slovenia was found in a small dialysis unit with old equipment and room shortage, where the first anti-HCV-positive pat ient was detected in 1990. In 1992 and 1993, an additional 8 and 7 pat ients seroconverted, respectively. Genotyping analyses among 15 HCV RN A-positive patients showed quite unusual HCV genotype distribution for our country: genotypes 2 and 3 were determined in 9 and 6 patients, r espectively. Sequence analysis of the 270-bp part of the NS-5 region w as carried out in 12 patients. In 6 patients infected with subtype 2c and in 4 patients infected with subtype 3a, very similar sequences wer e obtained, forming two distinct clusters in the phylogenetic tree. In 2 patients infected with subtype 2c, viral strains were neither relat ed to the main 2c strain nor to each other. Phylogenetic analysis uneq uivocally confirmed simultaneous nosocomial spread of two different HC V strains in one hemodialysis unit. The study confirmed that implement ation of rigorous hygienic routines and introduction of separate rooms and machines for HCV-infected patients are important measures for eff ective control of HCV infection in a hemodialysis environment.