Method: ETV resistance: Two or more amino acid substitutions are required across the HBV RT protein to confer resistance to ETV which could occur as a combination of M204I/V with one or more of the following substitutions L80I/V, I163V, I169T, V173L, L180M, A181S/T/V, T184X, A186T, S202C/G/I/R, M250I/V and/or C256S/G.
Hepatitis B virus mutation pattern rtA181S+T184I+M204I may contribute to multidrug resistance in clinical practice: Analysis of a large cohort of Chinese patients.
Abstract: Artificial elimination of rtA181S from the rtA181S + T184I + M204I mutant restored viral susceptibility to ADV but decreased viral replication capacity.
Abstract: Compared with wild-type, the rtA181S + T184I + M204I mutant had 53.7% lower replication capacity and >1000-, 3.9-, and 383.3-fold greater LAM, ADV, and ETV resistance, respectively, but remained sensitive to tenofovir.
Abstract: Longitudinal analysis of the clinical course of resistant mutant evolution for four representative cases showed that rtA181S + T184I
Hepatitis B infection among HIV infected individuals in Gabon: Occult hepatitis B enhances HBV DNA prevalence.
Method: As previously described, we used the Mutation Reporter Tool (MRT) software (http://hvdr.bioinf.wits.ac.za/mrt/) to look for HBV resistance-associated mutations (RAMs) in the Polymerase catalytic domain represented by major RAMs (A181T/V/S, A194T, M204V/I/S and N236T) and compensatory RAMs (I169T, V173L, L180M, S202G/I and M250V.
Naturally occurring hepatitis B virus reverse transcriptase mutations related to potential antiviral drug resistance and liver disease progression.
PMID: 29713126
2018
World journal of gastroenterology
Method: For example, using direct sequencing of samples from treatment-naive patients from the United States, Nguyen et al demonstrated that only four (0.9%) of 472 patients were infected with viruses with primary and secondary mutations (rtA181A/S, rtA194S, and rtM250I).
A systematic review of hepatitis B virus (HBV) drug and vaccine escape mutations in Africa: A call for urgent action.
Result: Overall, the most prevalent RAM was rtM204V/I in both treatment experienced and treatment naive individuals, and occurring either alone or in combination with other polymorphisms rtL80I/V, rtV173L, rtL180M, rtA181S, rtT184S, rtA200V and/or rtS202S (Fig 3); mutations among individuals with and without exposure to HBV therapy are listed in S4 Table and S5 Table, respectively).
Discovery of the Novel Entecavir-Resistant Hepatitis B Virus Reverse Transcriptase A181C Substitution From an Integrated Genotypic Analysis.
Result: In addition, recombinant clones were also constructed from patient isolates harboring other rtA181 substitutions, including rtA181G (Pt24), rtA181V (Pt24), rtA181N (Pt27), rtA181S (Pt28), and rtA181T (Pt29).
Result: In addition, they did not confer cross-resistance to ADV or TDV with the exception of the rtA181S substitution that has been reported to confer cross-resistance to ADV.( 28 ) .
Result: Phenotypic analysis of a recombinant clone harboring rtA181
Genotyping of HBV and tracking of resistance mutations in treatment-naive patients with chronic hepatitis B.
Abstract: The mutations were rtA194T, rtL180M + rtM204V, rtS202I, rtM204I, and rtA181S.
Hepatitis B virus mutation pattern rtA181S+T184I+M204I may contribute to multidrug resistance in clinical practice: Analysis of a large cohort of Chinese patients.
Abstract: All rtA181S-positive patients had received nucleos(t)ide analogues.
Abstract: Genotype C and genotype B HBV infection occupied 91.8% and 8.2% in rtA181S-positive patients, in contrast to 84.6% and 15.4% in rtA181S-negative patients (P < 0.01).
Abstract: Phenotypic analysis of patient-derived viral strains showed that rtA181S, rtA181S+N236T, rtN236T and rtA181V strains had 68.5%, 49.9%, 71.4% and 66.2
Epidemiology study of HBV genotypes and antiviral drug resistance in multi-ethnic regions from Western China.
Result: As shown in Table 2, ADV-associated mutation rtA181V/T/S demonstrated a remarkable higher prevalence in genotype C than genotype B (13.5% vs.
Result: Interestingly, cross-resistant mutation rate of rtA181V/T/S was higher in patients harboring genotype C than genotype B in LMV-resistant patients (29.3% vs.
HBV mutation literature information.
PMID: 
2022
Frontiers in microbiology
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