Molecular characterization of hepatitis B virus X gene in HIV-positive South Africans.

Hepatitis B virus (HBV) infection is a major public health problem worldwide and the major cause of hepatocellular carcinoma (HCC) in South Africa. The role of HBV in HCC is not well understood, although the HBV X gene has been implicated as a critical factor. Data on the HBV X gene in HIV-positive South Africans are limited; thus, we investigated X gene variability in 24 HIV-infected treatment-naïve patients at Dr George Mukhari Academic Hospital. Quantitative and qualitative HBV DNA tests were conducted using real-time and in-house polymerase chain reaction (PCR) assays, respectively, targeting the complete HBV X gene. In-house PCR-positive samples were cloned using the P-Gem T-easy vector System II and sequenced. By phylogenetic analysis, X gene sequences were classified as subgenotype A1 (n = 15), A2 (n = 4), and D1 (n = 4), and one dual infection with subgenotypes as A1 and C. The basal core promoter mutations T1753C, A1762T, and G1764A were identified in the majority of sequences. Genotype D sequences had a 6-nucleotide insertion. In conclusion, subgenotype A1 was predominant, and a rare dual infection of HBV genotype A and C was detected. The 6-nucleotide insertion could represent a unique variant in the region and highlights the need for functional studies of HBV X gene variants, particularly from resource-limited settings.

High prevalence of active and occult hepatitis B virus infections in healthcare workers from two provinces of South Africa.

BACKGROUND: Hepatitis B (HB) is a vaccine-preventable liver disease caused by infection with the blood-borne hepatitis B virus (HBV). South African healthcare workers (HCWs) may be at high risk of occupational exposure to HBV infection, since previous studies have found suboptimal levels of protection against HBV in HCWs. METHODS: A descriptive prevalence study based on self-administered questionnaires with data on demographics and HB vaccination status, and stored serum samples collected from 2009 to 2012, from 333 HCWs working or studying in Gauteng and Mpumalanga province hospitals or nursing colleges, was conducted. Samples were tested for HB surface antigen (HBsAg), antibodies to HBsAg (anti-HBs), antibodies to HB core antigen (anti-HBc), and HBV deoxyribonucleic acid (DNA). RESULTS: The majority of HCWs from whom the serum samples were drawn were black (91.4% [298/326]), female (82.6% [275/333]) and had received at least one dose of HB vaccine (70.9% [236/333]). The average age was 38.8years (range: 19-62). Of the HCWs, 23.2% (73/314) were susceptible (negative for all markers); 9.6% (30/314) were infected (HBsAg and/or DNA positive); 29.0% (91/314) were exposed (positive for either HBsAg, anti-HBc, or DNA); 18.8% (59/314) were immune due to natural infection (anti-HBs and anti-HBc positive only); while 47.8% (150/314) were immune due to vaccination (anti-HBs positive only). Furthermore, HBV DNA was detected in 8.6% (27/314) and occult HBV infection (OBI) (HBV DNA positive but HBsAg negative) was found in 6.7% (21/314) of samples. DISCUSSION AND CONCLUSION: This study, which is the first to report OBI in South African HCWs, found high rates of active HBV infection and sub-optimal protection against HBV in HCWs. There is a need to strengthen vaccination programmes through a policy that ensures protection for all HCWs and their patients.