OBJECTIVE: To describe outbreaks of nosocomial influenza infection with molecular methods and to elucidate the viral linkages among outbreak case patients including both inpatients and healthcare workers (HCWs). SETTING: A 180-bed acute and long-term care hospital in Japan. METHODS: Retrospective observational study of nosocomial outbreaks of infection with influenza A/H3N2. Together with information about onset dates and vaccination history, we obtained nasopharyngeal swab samples from individuals with cases of influenza or influenza-like illness (ILI). The hemagglutinin genes of the recovered viruses were sequenced and compared, along with those of community-circulating strains, for similarity by phylogenetic tree analysis. RESULTS: The outbreaks occurred from February 26 through April 3, 2007, during the 2006-2007 epidemic season, and they involved 11 patients and 13 HCWs. The 2 outbreaks involved 2 different genotypes of influenza A/H3N2 viruses. These virus variants were closely related to the influenza strains that were circulating in the community during the same epidemic season. CONCLUSION: This study showed the dissemination of highly homologous influenza virus variants among inpatients and HCWs within a short period, as a result of nosocomial transmission. These strains were also similar to influenza strains that were circulating in the community.
OBJECTIVE: To describe outbreaks of nosocomial influenza infection with molecular methods and to elucidate the viral linkages among outbreak case patients including both inpatients and healthcare workers (HCWs). SETTING: A 180-bed acute and long-term care hospital in Japan. METHODS: Retrospective observational study of nosocomial outbreaks of infection with influenzaA/H3N2. Together with information about onset dates and vaccination history, we obtained nasopharyngeal swab samples from individuals with cases of influenza or influenza-like illness (ILI). The hemagglutinin genes of the recovered viruses were sequenced and compared, along with those of community-circulating strains, for similarity by phylogenetic tree analysis. RESULTS: The outbreaks occurred from February 26 through April 3, 2007, during the 2006-2007 epidemic season, and they involved 11 patients and 13 HCWs. The 2 outbreaks involved 2 different genotypes of influenzaA/H3N2 viruses. These virus variants were closely related to the influenza strains that were circulating in the community during the same epidemic season. CONCLUSION: This study showed the dissemination of highly homologous influenza virus variants among inpatients and HCWs within a short period, as a result of nosocomial transmission. These strains were also similar to influenza strains that were circulating in the community.
Authors: Helen Y Chu; Janet A Englund; Sara Podczervinski; Jane Kuypers; Angela P Campbell; Michael Boeckh; Steven A Pergam; Corey Casper Journal: Biol Blood Marrow Transplant Date: 2014-03-06 Impact factor: 5.742