Molecular And Computational Analysis Of Natural Drug Resistance Mutations Among Moroccan Chronic Hepatitis B Carriers

Despite the effectiveness of nucleotide analogs (NAs), drug resistance and cccDNA inaccessibility are still significant obstacles to long-term efficacy of antiviral therapy in chronic hepatitis B infection (CHB). Mutations pre-exist spontaneously in Hepatitis B Virus (HBV) reverse transcriptase (RT) gene in minor viral populations and can emerge to confer drug resistance and treatment failure. This study aimed to analyze mutations within the HBV polymerase gene in treatment-naive Moroccan patients with CHB.The HBV polymerase gene was analyzed by nested-PCR and direct sequencing in 123 subjects. A computational analysis was performed to confirm the effect of detected mutations on targeted NAs, using homology and docking tools.Sixty samples were successfully amplified by PCR. Analyses revealed an intermediate rate (13%) of pre-treatment NA resistance mutations and a high frequency of putative resistance mutations (65%). Among these, 56% were lamivudine resistance mutations and 44% adefovir resistance mutations. Two pretreatment resistance mutations, "Y124N" and "N139D/K/H/Q" were detected in 8/60 patients, and 11 putative resistance mutations (N53S/T/D, L91I, H126Y, T128I, V207I, V214A, Q215P/S, L217R, F221Y, L229V, N238H/T) in 39/60 patients, where two have a combination of F221Y and A194T "a classical NA drug resistance mutation." The computational analysis demonstrated that the combination of A194T + F221Y mutations on HBV RT sequence does not affect its susceptibility to ADV.These results confirm that HBV mutations conferring resistance against currently available anti-HBV NA predate treatment in naive Moroccan patients. The high rate of non-classical NA resistance mutations needs further in vitro phenotype analysis.