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Molecular epidemiology of hepatitis B virus isolated from Bangladesh

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ABSTRACT

Background: Hepatitis B virus (HBV) is highly contagious and causes liver diseases. Globally more than 350 million people are chronically infected and among them above 80 % are from developing countries like Bangladesh. Resistance to existing drugs and vaccines are common phenomenon due to mutations in HBsAg ‘a’ determinant. Due to lack of data about mutations and subtypes of HBV in Bangladesh, this study strongly demands to be documented. Here, we determined the genotypes and subtypes of HBV prevalent in Bangladesh, and their genomic mutations associated with vaccine and drug resistance.

Results: Among 385 samples, a total of 54 (14 %) were found HBV positive, of which 19 samples were subjected to be sequenced. After bioinformatic analysis, we found Genotype D as predominant genotype (73.7 %) with subtypes ayw3 (64.3 %) and ayw2 (35.7 %), followed by genotype A with subtype adw2 (15.8 %), and then genotype C with subtype adr (10.5 %). A significant number of mutations (Thr118Val, Thr125Met, Thr126Ile, Pro127Thr, Ala128Val, Thr131Asn/Ser, Thr/Ser143Leu/Met) were found in ‘a’ determinant region which may admit resistance to the available vaccines and failure of HBsAg detection.

Conclusions: This comprehensive study have clinical importance like disease diagnosis and treatment. It emphasizes HBV infected patients to do molecular diagnosis for choice of anti-viral drugs and effectiveness of vaccines for proper treatment.

No MeSH data available.


Alignment of HBV sequences with a different Bangladeshi strains and b foreign strains. Our experimental sequences have been marked with boxes. Matched amino acids were presented as dot and mismatched were shown in symbols. Alignment was done by MEGA v5.0 software and visualized using Jalview v2.8.1 software
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Fig3: Alignment of HBV sequences with a different Bangladeshi strains and b foreign strains. Our experimental sequences have been marked with boxes. Matched amino acids were presented as dot and mismatched were shown in symbols. Alignment was done by MEGA v5.0 software and visualized using Jalview v2.8.1 software

Mentions: After constructing phylogenetic tree, we observed strong similarity of our partial S protein sequence with other Bangladeshi sequences (up to 97 %) and sequences from India (up to 100 %) and Malaysia (96 %) as shown in Fig. 2. However, sequences comprising genotype D were evolutionarily diverted (Fig. 2). On the other hand, there were several amino acid mutations like K122R (amino acid Lysine at 122 position of S protein instead of Arginine), T131S and I208T in genotype C (Fig. 3). The above mutations might have possible effect on structural and functional activity of S protein which might be a significant cause of resistance. Phylogenetic tree of above alignment revealed that our sequences were closely related with other Bangladeshi existing sequences with a similarity of more than 90 % (Fig. 2a). Phylogenetic analysis revealed the highest similarity of genotype A, C and D sequences with the sequences from India, Malaysia and India respectively (Fig. 2b).Fig. 2


Molecular epidemiology of hepatitis B virus isolated from Bangladesh
Alignment of HBV sequences with a different Bangladeshi strains and b foreign strains. Our experimental sequences have been marked with boxes. Matched amino acids were presented as dot and mismatched were shown in symbols. Alignment was done by MEGA v5.0 software and visualized using Jalview v2.8.1 software
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016485&req=5

Fig3: Alignment of HBV sequences with a different Bangladeshi strains and b foreign strains. Our experimental sequences have been marked with boxes. Matched amino acids were presented as dot and mismatched were shown in symbols. Alignment was done by MEGA v5.0 software and visualized using Jalview v2.8.1 software
Mentions: After constructing phylogenetic tree, we observed strong similarity of our partial S protein sequence with other Bangladeshi sequences (up to 97 %) and sequences from India (up to 100 %) and Malaysia (96 %) as shown in Fig. 2. However, sequences comprising genotype D were evolutionarily diverted (Fig. 2). On the other hand, there were several amino acid mutations like K122R (amino acid Lysine at 122 position of S protein instead of Arginine), T131S and I208T in genotype C (Fig. 3). The above mutations might have possible effect on structural and functional activity of S protein which might be a significant cause of resistance. Phylogenetic tree of above alignment revealed that our sequences were closely related with other Bangladeshi existing sequences with a similarity of more than 90 % (Fig. 2a). Phylogenetic analysis revealed the highest similarity of genotype A, C and D sequences with the sequences from India, Malaysia and India respectively (Fig. 2b).Fig. 2

View Article: PubMed Central - PubMed

ABSTRACT

Background: Hepatitis B virus (HBV) is highly contagious and causes liver diseases. Globally more than 350 million people are chronically infected and among them above 80 % are from developing countries like Bangladesh. Resistance to existing drugs and vaccines are common phenomenon due to mutations in HBsAg ‘a’ determinant. Due to lack of data about mutations and subtypes of HBV in Bangladesh, this study strongly demands to be documented. Here, we determined the genotypes and subtypes of HBV prevalent in Bangladesh, and their genomic mutations associated with vaccine and drug resistance.

Results: Among 385 samples, a total of 54 (14 %) were found HBV positive, of which 19 samples were subjected to be sequenced. After bioinformatic analysis, we found Genotype D as predominant genotype (73.7 %) with subtypes ayw3 (64.3 %) and ayw2 (35.7 %), followed by genotype A with subtype adw2 (15.8 %), and then genotype C with subtype adr (10.5 %). A significant number of mutations (Thr118Val, Thr125Met, Thr126Ile, Pro127Thr, Ala128Val, Thr131Asn/Ser, Thr/Ser143Leu/Met) were found in ‘a’ determinant region which may admit resistance to the available vaccines and failure of HBsAg detection.

Conclusions: This comprehensive study have clinical importance like disease diagnosis and treatment. It emphasizes HBV infected patients to do molecular diagnosis for choice of anti-viral drugs and effectiveness of vaccines for proper treatment.

No MeSH data available.