Journal Article

Cluster of Oseltamivir-Resistant 2009 Pandemic Influenza A (H1N1) Virus Infections on a Hospital Ward among Immunocompromised Patients—North Carolina, 2009

Fry, Alicia M., Duffy, Jonathan, Greenwald, Ian, Wolfe, Cameron R., Fleischauer, Aaron T., Gubareva, Larisa V., Deyde, Varough M., Rao, Agam K., Srinivasan, Arjun, Sexton, Daniel J., Dailey, Natalie J. M., Anderson, Deverick J., Chen, Luke F., Moore, Zack S.

2011

Overview

Background. Oseltamivir resistance among 2009 pandemic influenza A (H1N1) viruses (pH1N1) is rare. We investigated a cluster of oseltamivir-resistant pH1N1 infections in a hospital ward. Methods. We reviewed patient records and infection control measures and interviewed health care personnel (HCP) and visitors. Oseltamivir-resistant pH1N1 infections were found with real-time reverse-transcription polymerase chain reaction and pyrosequencing for the H275Y neuraminidase (NA) mutation. We compared hemagglutinin (HA) sequences from clinical samples from the outbreak with those of other surveillance viruses. Results. During the period 6-11 October 2009, 4 immunocompromised patients within a hematologyoncology ward exhibited symptoms of pHlNl infection. The likely index patient became febrile 8 days after completing a course of oseltamivir; isolation was instituted 9 days after symptom onset. Three other case patients developed symptoms 1, 3, and 5 days after the index patient. Three case patients were located in adjacent rooms. HA and NA sequences from case patients were identical. Twelve HCP and 6 visitors reported influenza symptoms during the study period. No other pHlNl isolates from the hospital or from throughout the state carried the H275Y mutation. Conclusions. Geographic proximity, temporal clustering, presence of H275Y mutation, and viral sequence homology confirmed nosocomial transmission of oseltamivir-resistant pH1N1. Diagnostic vigilance and prompt isolation may prevent nosocomial transmission of influenza.

• Publisher: Oxford University Press
• Subject: Adult / Aged / Antiviral Agents - pharmacology / Biological and medical sciences / Case-Control Studies / Cross Infection - epidemiology / Cross Infection - virology / Disease Outbreaks / Disease transmission / Drug Resistance, Viral / Fever / Fundamental and applied biological sciences. Psychology / H1N1 subtype influenza A virus / Hospitals / Humans / Immunocompromised Host / Infections / Infectious diseases / Influenza A virus / Influenza A Virus, H1N1 Subtype - classification / Influenza A Virus, H1N1 Subtype - drug effects / Influenza A Virus, H1N1 Subtype - genetics / Influenza, Human - drug therapy / Influenza, Human - epidemiology / Interviews as Topic / Major and Brief Reports / Medical sciences / Microbiology / Middle Aged / North Carolina - epidemiology / Oseltamivir - pharmacology / Pandemics / Phylogeny / Retrospective Studies / Sequencing / Specimens / Symptoms / Viruses