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Study of oseltamivir and zanamivir resistance-related mutations in influenza viruses isolated from wild mallards in Sweden.

Orozovic G, Orozovic K, Järhult JD, Olsen B - PLoS ONE (2014)

Bottom Line: IC50 values confirmed the differences in sensitivity to OC or ZA observed in the N1 and N2 groups of NAs.Furthermore, both wild types (WTs) in the N6 and one WT in the N9 subtype were less sensitive to ZA than were genotypically related mutants with R152K and R118K change in the respective subtypes.This may indicate that these and probably even other NAIs resistance-related mutations found in our virus collection were not induced by NAIs residuals in the environment and that the impact of such mutations in an avian influenza could be dependent on subtype, strain and host species.

View Article: PubMed Central - PubMed

Affiliation: Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.

ABSTRACT
Resistance to neuraminidase inhibitors (NAIs) is a growing problem in battle against influenza A virus. However, little is known about the resistance of viruses isolated from dabbling ducks, the natural reservoir of the influenza virus. To our knowledge, no low-pathogenic avian influenza (LPAI) virus resistant to NAIs has been detected. The aim of this study was to investigate mallard isolates of influenza A virus previously identified to carry oseltamivir carboxylate (OC) or zanamivir (ZA) resistance-related mutations. In this work, 21 viruses belonging to the N1, N3, N6 and N9 subtypes were analyzed using a colorimetric NA inhibition assay. The results of assay showed no NAIs-resistant phenotype for any of the viruses. The R118K mutation was the most recurrent, as it was observed in all subtypes except for N6. IC50 values confirmed the differences in sensitivity to OC or ZA observed in the N1 and N2 groups of NAs. Furthermore, both wild types (WTs) in the N6 and one WT in the N9 subtype were less sensitive to ZA than were genotypically related mutants with R152K and R118K change in the respective subtypes. This may indicate that these and probably even other NAIs resistance-related mutations found in our virus collection were not induced by NAIs residuals in the environment and that the impact of such mutations in an avian influenza could be dependent on subtype, strain and host species.

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Sequence alignment of N2 reference, and three N1 sensitive mutants.The sequence interval between the 121th and 149th amino acid (marked with - - - ; N2 reference numbering) is excluded from alignment for practical reasons. The relevant mutation sites are indicated in red. (r) - reference sequence; Number within the parenthesis indicate code for virus isolates according Table 2. (3) - H1N1 R118K mutant; (4) - H1N1 R118K/D151N mutant; (14) - H6N1 R118K/D151N/D198N mutant. Cl.Co- ClustalW consensus sequence, “*” is used to indicate identical residues, “:” is used to indicate conserved substitution, “.” is used to indicate semi-conserved substitution, “ ” (empty space) is used to indicate dissimilar residues.
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pone-0089306-g001: Sequence alignment of N2 reference, and three N1 sensitive mutants.The sequence interval between the 121th and 149th amino acid (marked with - - - ; N2 reference numbering) is excluded from alignment for practical reasons. The relevant mutation sites are indicated in red. (r) - reference sequence; Number within the parenthesis indicate code for virus isolates according Table 2. (3) - H1N1 R118K mutant; (4) - H1N1 R118K/D151N mutant; (14) - H6N1 R118K/D151N/D198N mutant. Cl.Co- ClustalW consensus sequence, “*” is used to indicate identical residues, “:” is used to indicate conserved substitution, “.” is used to indicate semi-conserved substitution, “ ” (empty space) is used to indicate dissimilar residues.

Mentions: NAs of all subtypes have 19 conserved amino acids that function either as catalytic residues (R118, D151, R152, R224, E276, R292, R371 and Y406) or as framework residues (E119, R156, W178, S179, D198, I222, E227, H274, E277, N294 and E425) [26]. The majority of the mutations related to the NAI resistance have been found in or in close proximity to these sites. The literature describing NAI resistance mutations has been reviewed [30], [31], [32], [33], [34], whereupon nine OC (V116A, I117V, E119V, D198N, I222V, H274Y, R292K, N294S and I314V) and ten ZA (V116A, R118K, E119G/A/D, Q136K, D151E/G/N, R152K, R224K, E276D, R292K and R371K) NAI resistance-related mutations were identified (N2 numbering). ClustalW alignments of all sequences and the N2 reference sequence (GenBank ID: CAD35677) were performed for each NA subtype and the sequences were scanned (Figure 1) for each of the above mentioned mutations [26].


Study of oseltamivir and zanamivir resistance-related mutations in influenza viruses isolated from wild mallards in Sweden.

Orozovic G, Orozovic K, Järhult JD, Olsen B - PLoS ONE (2014)

Sequence alignment of N2 reference, and three N1 sensitive mutants.The sequence interval between the 121th and 149th amino acid (marked with - - - ; N2 reference numbering) is excluded from alignment for practical reasons. The relevant mutation sites are indicated in red. (r) - reference sequence; Number within the parenthesis indicate code for virus isolates according Table 2. (3) - H1N1 R118K mutant; (4) - H1N1 R118K/D151N mutant; (14) - H6N1 R118K/D151N/D198N mutant. Cl.Co- ClustalW consensus sequence, “*” is used to indicate identical residues, “:” is used to indicate conserved substitution, “.” is used to indicate semi-conserved substitution, “ ” (empty space) is used to indicate dissimilar residues.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928424&req=5

pone-0089306-g001: Sequence alignment of N2 reference, and three N1 sensitive mutants.The sequence interval between the 121th and 149th amino acid (marked with - - - ; N2 reference numbering) is excluded from alignment for practical reasons. The relevant mutation sites are indicated in red. (r) - reference sequence; Number within the parenthesis indicate code for virus isolates according Table 2. (3) - H1N1 R118K mutant; (4) - H1N1 R118K/D151N mutant; (14) - H6N1 R118K/D151N/D198N mutant. Cl.Co- ClustalW consensus sequence, “*” is used to indicate identical residues, “:” is used to indicate conserved substitution, “.” is used to indicate semi-conserved substitution, “ ” (empty space) is used to indicate dissimilar residues.
Mentions: NAs of all subtypes have 19 conserved amino acids that function either as catalytic residues (R118, D151, R152, R224, E276, R292, R371 and Y406) or as framework residues (E119, R156, W178, S179, D198, I222, E227, H274, E277, N294 and E425) [26]. The majority of the mutations related to the NAI resistance have been found in or in close proximity to these sites. The literature describing NAI resistance mutations has been reviewed [30], [31], [32], [33], [34], whereupon nine OC (V116A, I117V, E119V, D198N, I222V, H274Y, R292K, N294S and I314V) and ten ZA (V116A, R118K, E119G/A/D, Q136K, D151E/G/N, R152K, R224K, E276D, R292K and R371K) NAI resistance-related mutations were identified (N2 numbering). ClustalW alignments of all sequences and the N2 reference sequence (GenBank ID: CAD35677) were performed for each NA subtype and the sequences were scanned (Figure 1) for each of the above mentioned mutations [26].

Bottom Line: IC50 values confirmed the differences in sensitivity to OC or ZA observed in the N1 and N2 groups of NAs.Furthermore, both wild types (WTs) in the N6 and one WT in the N9 subtype were less sensitive to ZA than were genotypically related mutants with R152K and R118K change in the respective subtypes.This may indicate that these and probably even other NAIs resistance-related mutations found in our virus collection were not induced by NAIs residuals in the environment and that the impact of such mutations in an avian influenza could be dependent on subtype, strain and host species.

View Article: PubMed Central - PubMed

Affiliation: Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.

ABSTRACT
Resistance to neuraminidase inhibitors (NAIs) is a growing problem in battle against influenza A virus. However, little is known about the resistance of viruses isolated from dabbling ducks, the natural reservoir of the influenza virus. To our knowledge, no low-pathogenic avian influenza (LPAI) virus resistant to NAIs has been detected. The aim of this study was to investigate mallard isolates of influenza A virus previously identified to carry oseltamivir carboxylate (OC) or zanamivir (ZA) resistance-related mutations. In this work, 21 viruses belonging to the N1, N3, N6 and N9 subtypes were analyzed using a colorimetric NA inhibition assay. The results of assay showed no NAIs-resistant phenotype for any of the viruses. The R118K mutation was the most recurrent, as it was observed in all subtypes except for N6. IC50 values confirmed the differences in sensitivity to OC or ZA observed in the N1 and N2 groups of NAs. Furthermore, both wild types (WTs) in the N6 and one WT in the N9 subtype were less sensitive to ZA than were genotypically related mutants with R152K and R118K change in the respective subtypes. This may indicate that these and probably even other NAIs resistance-related mutations found in our virus collection were not induced by NAIs residuals in the environment and that the impact of such mutations in an avian influenza could be dependent on subtype, strain and host species.

Show MeSH
Related in: MedlinePlus