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Abstract: Background: Monitoring the emergence of drug-resistant influenza variants is crucial in influenza surveillance programs. Objectives: Influenza A kinetics and the emergence of drug-resistant strains in hospitalized patients treated with oseltamivir were investigated. Study design: Sequential samples from oseltamivir-treated and -untreated hospitalized patients in the period November 2011 through April 2012 were analyzed. NA gene was sequenced in samples from oseltamivir treated patients. Clonal analysis of the viral population was performed in patients unresponsive to treatment. Viral kinetics was determined in 24 (14 immunocompromised and 10 immunocompetent) A(H3N2)-positive patients treated and 24 (10 immunocompromised and 14 immunocompetent) untreated patients. Results: Viral shedding was significantly reduced in treated vs untreated immunocompromised patients (7 vs 22 days, p <0.05, respectively). Viral load decreased significantly in immunocompromised and immunocompetent treated patients as compared with immunocompromised and immunocompetent untreated patients (0.73 and 0.93 vs 0.47 and 0.45log10/day, p <0.05). In two (8.3%) treated patients with prolonged virus shedding, the oseltamivir resistance R292K mutation was revealed. In these patients, clonal analysis of the virus population showed the presence of additional oseltamivir-resistant mutants (E119V, N294S and deletion Del247–250). Conclusions: Oseltamivir resistance is reported for the first time in A(H3N2) virus strains during the 2011–2012 influenza season. Different drug-resistant viruses emerged in hospitalized immunocompromised patients showing prolonged virus shedding. [Copyright &y& Elsevier]

Background WU and KI polyomaviruses were discovered in 2007 in samples of respiratory secretions of children with acute respiratory symptoms. Seroepidemiologic studies have shown that these viruses are widely distributed throughout the world, but their incidence in Spain has not been determined. In transplant patients, early detection and treatment of viral infections may influence prognosis and survival, because they are associated with increased morbidity and mortality, including graft failure. Methods We aimed to determine the prevalence and clinical characteristics of WU and KI polyomaviruses among patients undergoing hematologic or solid organ transplant in the Hospital Marqués de Valdecilla (Santander, Spain). An in-house polymerase chain reaction with the use of specific primers was carried out in invasive lower respiratory samples from hospitalized patients with suspected respiratory infection and/or graft dysfunction and compared with asymptomatic transplant patients. Results Overall, we obtained 5.5% KI-positive samples and 1.4% WU-positive samples, with a higher prevalence of WU and KI polyomaviruses in the symptomatic population compared with the control group. Although the data suggest that their detection in respiratory samples is sporadic and often associated with other microorganisms, we should pay special attention to their association with cases of graft failure. Studies are needed with a larger number of samples to explore the potential clinical impact of these emerging polyomaviruses in transplant recipients. [ABSTRACT FROM AUTHOR]