Transmission of hepatitis C virus in a gynecological surgery setting.

A cluster of hepatitis C virus (HCV) infections among gynecological patients who underwent surgical intervention in the same setting is described. An epidemiological investigation was conducted to identify the cases, the likely source of infection, and the route of transmission. Four recent HCV infections were identified. Based on molecular fingerprinting analysis and epidemiological investigation, transmission between the putative source patient (an HCV-positive woman who was the first patient of the surgical session) and outbreak patients was highly suggestive. All patients, including the source patient, were infected with HCV type 1b. Molecular characterization of HCV clones by sequence analysis of both structural envelope regions (20 clones from the source patient and 58 from the outbreak patients) and the nonstructural NS5 region of the viral genome (12 clones from the source patient and 32 from the outbreak patients) showed close homology between the viral isolates from the source and those from the outbreak patients that was higher than that observed between the viral isolates from the source and those from four unrelated, HCV type 1b-infected patients from the same geographical area (in the latter case, 33 clones were sequenced for the envelope regions and 30 were sequenced for the NS5 region). The mean percent divergence between clones was 4.69 for the envelope and 3.71 for the NS5 region in the source patient and the outbreak patients compared with 6.76 (P = 0.001) and 5.22 (P = 0.01) in the source patient and control patients, respectively. Among the risk factors investigated, only that of having undergone surgery in the morning session of the same day reached statistical significance (P = 0.003). The investigation showed that the source patient and outbreak patients shared only the administration of propofol in multidose vials. The study documents the risk of nosocomial transmission of HCV and the importance of infection control procedures in the operating room and highlights the crucial role of molecular strategies, especially sequence-based phylogenetic analysis of cloned viral isolates, in the investigation of HCV outbreaks.