Notes from the Field: Hepatitis C Outbreak in a Dialysis Clinic — Tennessee, 2014 Weekly – January 1, 2016
Outbreaks of hepatitis C virus (HCV) infections can occur among hemodialysis patients when recommended infection control practices are not followed (1). On January 30, 2014, a dialysis clinic in Tennessee identified acute HCV in a patient (patient A) during routine screening and reported it to the Tennessee Department of Health. Patient A had enrolled in the dialysis clinic in March 2010 and had annually tested negative for HCV (including a last HCV test on December 19, 2012), until testing positive for HCV antibodies (anti-HCV) on December 18, 2013 (confirmed by a positive HCV nucleic acid amplification test). Patient A reported no behavioral risk factors, but did have multiple health care exposures.
On April 16, 2014, the Tennessee Department of Health observed infection control practices at the clinic. Clinic officials reported that no changes to infection control protocols at the dialysis clinic had been made from the time patient A was identified to this date of observation. The health department observers noted that no visible blood was present on any surfaces, sinks were easily accessible, staff hand hygiene was performed consistently, and gloves and other personal protective equipment were used appropriately. Individual patient stations were disinfected after the previous patient left the station, with a 1:100 diluted household bleach solution, and surfaces were allowed to dry completely between patients. Medications were prepared for each patient in a separate, clean medication room at the time of administration; no multidose medication vials were carried into patient care areas. Blood for glucose testing was drawn from dialysis access sites with a syringe and tested by a glucometer in the laboratory. The glucometer was adequately disinfected between uses. Monthly trainings in infection control had been consistently provided to all staff members before the outbreak was identified.
Sixty-two dialysis patients were being treated at the clinic at the time of the investigation; all were retested for HCV. Nine (15%) patients, including patient A, were HCV-infected; specimens from patient A and five other chronically infected dialysis patients were positive for HCV genotype 1a (Figure), the remaining three were positive for genotype 1b. Genotype 1a is the most prevalent genotype in the United States (2). Patient B, who seroconverted in December 2010, had a history of injection drug use, which, at the time of diagnosis, was considered to be the source of exposure. Patient C was chronically infected and had tested positive for HCV upon admission at the dialysis clinic. Infection duration for all other HCV infected patients, including patient C, was unknown.
Quasispecies (HCV intra-genotype variants) analysis was performed from serum specimens collected from all nine patients found to be HCV positive. Patients A, B, and C were infected with genotype 1a; less than 5% nucleotide variation among intra-host HCV sequences was detected among the three patients, suggesting epidemiologic linkage of these infections (Figure). On separate occasions, patients A and B underwent dialysis on the same machine following patient C, during the most likely exposure periods (January–May 2013 for patient A and November 2009–June 2010 for patient B). Hospitalization events for patients A, B, and C during the likely exposure periods did not overlap in space and time. No other common exposures were identified.