Mutation analysis of hepatitis B virus reverse transcriptase region among untreated chronically infected patients in Ahvaz city (South-West of Iran).
BACKGROUND
It has been revealed that mutations can occur spontaneously and naturally in HBV reverse transcriptase (RT) region among untreated patients. These HBV mutants pre-exist as minor viral population in naive patients and can emerge as major viral population, conferring drug resistance and treatment failure.


OBJECTIVE
The aim of this study was to investigate and identify prevalent mutations of RT region of hepatitis B virus genome in patients with chronic hepatitis B (CHB) untreated with antiviral drugs in South-West of Iran.


METHODS
A total of 45 cases with CHB who did not receive the treatment of lamivudine and any other antivirus drugs within the last one year were randomly chosen. After sample collection and HBV DNA extraction, RT region was amplified by polymerase chain reaction (PCR). Then PCR products were sequenced and HBV RT region mutations and amino acid changes were analyzed either manually or using web-based programs, on the basis of comparison of the obtained sequences with a set of HBV reference sequences.


RESULTS
A total of 23 (51.1%) mutations and amino acid changes were detected in studied 45 untreated patients. Of these, 3 (6.6%) patients had primary resistance mutation (rtM204I, rtA181T and rtA181S) and 20 (44.4%) patients had secondary resistance mutations.


CONCLUSIONS
High prevalence of mutations was found in HBV RT region of untreated patients. Most of these mutations were associated with resistance to adefovir and one patient had primary resistance mutation to lamivudine. Awareness of these resistance patterns might help in the antiviral therapy and for predicting clinical outcomes.
Infectious and Tropical Diseases Research Center , Ahvaz Jundishapur University of medical sciences, Ahvaz, Iran.
M
M
Hamidi-Fard
M
M
Makvandi
A
A
Samarbaf-Zadeh
E
E
Hajiani
A
A
Shayesteh
A
A
Masjedizadeh
D000293:Adolescent; D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D016133:Polymerase Chain Reaction; D012194:RNA-Directed DNA Polymerase / Q000235:genetics*; D017422:Sequence Analysis, DNA; D055815:Young Adult
D004279:DNA, Viral; D012194:RNA-Directed DNA Polymerase