tetano
Editor, Senior Moderator
Clin Infect Dis. 2013 Jan 10. [Epub ahead of print]
Global Assessment of Resistance to Neuraminidase Inhibitors: 2008-2011. The Influenza Resistance Information Study (IRIS).
Whitley RJ, Boucher CA, Lina B, Nguyen-Van-Tam JS, Osterhaus A, Schutten M, Monto AS.
Source
Department of Pediatrics, Microbiology, Medicine and Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA.
Abstract
Background. Following emergence of naturally occurring oseltamivir-resistant A/H1N1 viruses, a global observational investigation, the Influenza Resistance Information Study (IRIS; NCT00884117), was initiated in 2008 to study neuraminidase inhibitor (NAI) resistance and clinical outcome.Methods. Patients with influenza-like illness and/or positive rapid test results agreed to swabs of the posterior nares that were assessed by real-time RT-qPCR for influenza type and subtype and NAI resistance. RT-qPCR-positive specimens were cultured, sequenced and phenotypically tested for NAI resistance. Treatment was at the physician's discretion.Results. Of 1799 influenza-positive (RT-qPCR) patients, 1281 had influenza A (47 seasonal H1N1; 335 H3N2; 899 H1N1pdm2009) and 518 had influenza B. Antivirals were administered to 1041 (58%) patients (26, 245, 514 and 256, respectively). All seasonal H1N1 strains were genotypically (H275Y) and phenotypically resistant to oseltamivir. No genotypic resistance was detected in the Day 1 samples of any other viral subtypes. Mutation-specific (MS) RT-PCR detected resistance to oseltamivir in 19 patients post-baseline (17 H1N1pdm2009 [H275Y]; 2 H3N2 [R292 K]), 14 of whom were children aged ≤5 years. In 12/19 patients, viral loads were too low to permit cell culture and 14/19 were RT-qPCR-negative by Day 10. In one other H1N1pdm2009 patient, H275Y was detected by sequencing but not MS RT-PCR. No emergent resistance was found in influenza B infections.Conclusions. In years 1-3 of IRIS, emergent resistance to oseltamivir in influenza viruses during treatment was uncommon (2.2%) and mostly found in 1-5 year-olds. Viral loads were low in many cases and viral clearance rapid.
PMID:
23307766
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23307766
Global Assessment of Resistance to Neuraminidase Inhibitors: 2008-2011. The Influenza Resistance Information Study (IRIS).
Whitley RJ, Boucher CA, Lina B, Nguyen-Van-Tam JS, Osterhaus A, Schutten M, Monto AS.
Source
Department of Pediatrics, Microbiology, Medicine and Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, USA.
Abstract
Background. Following emergence of naturally occurring oseltamivir-resistant A/H1N1 viruses, a global observational investigation, the Influenza Resistance Information Study (IRIS; NCT00884117), was initiated in 2008 to study neuraminidase inhibitor (NAI) resistance and clinical outcome.Methods. Patients with influenza-like illness and/or positive rapid test results agreed to swabs of the posterior nares that were assessed by real-time RT-qPCR for influenza type and subtype and NAI resistance. RT-qPCR-positive specimens were cultured, sequenced and phenotypically tested for NAI resistance. Treatment was at the physician's discretion.Results. Of 1799 influenza-positive (RT-qPCR) patients, 1281 had influenza A (47 seasonal H1N1; 335 H3N2; 899 H1N1pdm2009) and 518 had influenza B. Antivirals were administered to 1041 (58%) patients (26, 245, 514 and 256, respectively). All seasonal H1N1 strains were genotypically (H275Y) and phenotypically resistant to oseltamivir. No genotypic resistance was detected in the Day 1 samples of any other viral subtypes. Mutation-specific (MS) RT-PCR detected resistance to oseltamivir in 19 patients post-baseline (17 H1N1pdm2009 [H275Y]; 2 H3N2 [R292 K]), 14 of whom were children aged ≤5 years. In 12/19 patients, viral loads were too low to permit cell culture and 14/19 were RT-qPCR-negative by Day 10. In one other H1N1pdm2009 patient, H275Y was detected by sequencing but not MS RT-PCR. No emergent resistance was found in influenza B infections.Conclusions. In years 1-3 of IRIS, emergent resistance to oseltamivir in influenza viruses during treatment was uncommon (2.2%) and mostly found in 1-5 year-olds. Viral loads were low in many cases and viral clearance rapid.
PMID:
23307766
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/23307766