tetano
Editor, Senior Moderator
Influenza Other Respir Viruses. 2018 Sep 14. doi: 10.1111/irv.12611. [Epub ahead of print]
[h=1]Replacement of neuraminidase inhibitor susceptible influenza A(H1N1) with resistant phenotype in 2008 and circulation of susceptible influenza A and B viruses during 2009-2013, South Africa.[/h] Treurnicht FK[SUP]1[/SUP], Buys A[SUP]1[/SUP], Tempia S[SUP]2,[/SUP][SUP]3[/SUP], Seleka M[SUP]1[/SUP], Cohen AL[SUP]2,[/SUP][SUP]4[/SUP], Walaza S[SUP]1,[/SUP][SUP]5[/SUP], Glass AJ[SUP]6[/SUP], Rossouw I[SUP]7[/SUP], McAnerney J[SUP]1[/SUP], Blumberg L[SUP]8,[/SUP][SUP]5[/SUP], Cohen C[SUP]1,[/SUP][SUP]5[/SUP], Venter M[SUP]9,[/SUP][SUP]10[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] Data on the susceptibility of influenza viruses from South Africa to neuraminidase inhibitors (NAIs) is scarce, and no extensive analysis was done.
[h=4]OBJECTIVES:[/h] We aimed to determine oseltamivir and zanamivir susceptibility of influenza A and B virus neuraminidases (NAs), 2007-2013, South Africa.
[h=4]PATIENTS/METHODS:[/h] We enrolled participants through national influenza-like illness surveillance, 2007-2013. Influenza diagnosis was by virus isolation and real-time polymerase chain reaction (qPCR). Drug susceptibility was determined by chemilluminescence-based NA-STAR/NA-XTD assay. Sanger sequencing was used to determine molecular markers of NAI resistance.
[h=4]RESULTS:[/h] Forty percent (6,341/15,985) of participants were positive for influenza viruses using virus isolation (2007-2009) and qPCR (2009-2013) methods. 1,236/6,341 (19.5%) virus isolates were generated of which 307/1,236 (25%) were tested for drug susceptibility. During 2007-2008 the median 50% inhibitory concentration (IC[SUB]50[/SUB] ) of oseltamivir for seasonal influenza A(H1N1) increased from of 0.08 nM (range 0.01-3.60) in 2007 to 73 nM (range 1.56-305 nM) in 2008. Influenza A isolates from 2009-2013 were susceptible to oseltamivir [A(H3N2) median IC[SUB]50[/SUB] = 0.05 nM (range 0.01-0.08); A(H1N1)pdm09= 0.11 nM (range 0.01-0.78)] and zanamivir [A(H3N2) median IC[SUB]50[/SUB] = 0.56 nM (range 0.47-0.66); A(H1N1)pdm09= 0.35 nM (range 0.27-0.533)]. Influenza B viruses were susceptible to both NAIs. NAI resistance-associated substitutions H275Y, E119V, and R150K (N1 numbering) were not detected in influenza A viruses that circulated in 2009-2013.
[h=4]CONCLUSIONS:[/h] We confirm replacement of NAI susceptible by resistant phenotype influenza A(H1N1) in 2008. Influenza A and B viruses (2009-2013) remained susceptible to NAIs; therefore these drugs are useful for treating influenza-infected patients. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[h=4]KEYWORDS:[/h] South Africa; influenza; oseltamivir; susceptibility
PMID: 30218485 DOI: 10.1111/irv.12611
Free full text
[h=1]Replacement of neuraminidase inhibitor susceptible influenza A(H1N1) with resistant phenotype in 2008 and circulation of susceptible influenza A and B viruses during 2009-2013, South Africa.[/h] Treurnicht FK[SUP]1[/SUP], Buys A[SUP]1[/SUP], Tempia S[SUP]2,[/SUP][SUP]3[/SUP], Seleka M[SUP]1[/SUP], Cohen AL[SUP]2,[/SUP][SUP]4[/SUP], Walaza S[SUP]1,[/SUP][SUP]5[/SUP], Glass AJ[SUP]6[/SUP], Rossouw I[SUP]7[/SUP], McAnerney J[SUP]1[/SUP], Blumberg L[SUP]8,[/SUP][SUP]5[/SUP], Cohen C[SUP]1,[/SUP][SUP]5[/SUP], Venter M[SUP]9,[/SUP][SUP]10[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] Data on the susceptibility of influenza viruses from South Africa to neuraminidase inhibitors (NAIs) is scarce, and no extensive analysis was done.
[h=4]OBJECTIVES:[/h] We aimed to determine oseltamivir and zanamivir susceptibility of influenza A and B virus neuraminidases (NAs), 2007-2013, South Africa.
[h=4]PATIENTS/METHODS:[/h] We enrolled participants through national influenza-like illness surveillance, 2007-2013. Influenza diagnosis was by virus isolation and real-time polymerase chain reaction (qPCR). Drug susceptibility was determined by chemilluminescence-based NA-STAR/NA-XTD assay. Sanger sequencing was used to determine molecular markers of NAI resistance.
[h=4]RESULTS:[/h] Forty percent (6,341/15,985) of participants were positive for influenza viruses using virus isolation (2007-2009) and qPCR (2009-2013) methods. 1,236/6,341 (19.5%) virus isolates were generated of which 307/1,236 (25%) were tested for drug susceptibility. During 2007-2008 the median 50% inhibitory concentration (IC[SUB]50[/SUB] ) of oseltamivir for seasonal influenza A(H1N1) increased from of 0.08 nM (range 0.01-3.60) in 2007 to 73 nM (range 1.56-305 nM) in 2008. Influenza A isolates from 2009-2013 were susceptible to oseltamivir [A(H3N2) median IC[SUB]50[/SUB] = 0.05 nM (range 0.01-0.08); A(H1N1)pdm09= 0.11 nM (range 0.01-0.78)] and zanamivir [A(H3N2) median IC[SUB]50[/SUB] = 0.56 nM (range 0.47-0.66); A(H1N1)pdm09= 0.35 nM (range 0.27-0.533)]. Influenza B viruses were susceptible to both NAIs. NAI resistance-associated substitutions H275Y, E119V, and R150K (N1 numbering) were not detected in influenza A viruses that circulated in 2009-2013.
[h=4]CONCLUSIONS:[/h] We confirm replacement of NAI susceptible by resistant phenotype influenza A(H1N1) in 2008. Influenza A and B viruses (2009-2013) remained susceptible to NAIs; therefore these drugs are useful for treating influenza-infected patients. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[h=4]KEYWORDS:[/h] South Africa; influenza; oseltamivir; susceptibility
PMID: 30218485 DOI: 10.1111/irv.12611
Free full text