Selection and viral load kinetics of an oseltamivir-resistant pandemic influenza A (H1N1) virus in an immunocompromised patient during treatment with neuraminidase inhibitors.
Prolonged viral excretion in immunocompromised hosts leads to long oseltamivir treatment and to the subsequent development of oseltamivir-resistant pandemic influenza virus selection. We report the selection and nasopharyngeal shedding kinetics of an oseltamivir-resistant strain in a hospitalized immunocompromised patient with prolonged influenza illness. Viral load quantification and genotyping methods were performed from 7 serial nasopharyngeal samples. Before initial oseltamivir treatment, the viral load was 5.78 log(10) copies/mL of sample and only wild-type virus population was detected. The nasopharyngeal viral load remained above the detection limit although there was a second course of oseltamivir treatment. Twelve days after the onset of symptoms, an oseltamivir-resistant strain was selected. After 12 days of inhaled zanamivir treatment, the patient was discharged asymptomatic. The study emphasizes the importance of viral load quantification and surveillance of emergence of resistant strains prospectively because the information provided has important implications in the clinical management of the patient.
Antón
Andrés
A
Microbiology Department, Hospital Clínic and Barcelona Centre for International Health Research (CRESIB), Barcelona, Spain. ananton@clinic.ub.es
López-Iglesias
Ana Alicia
AA
Tórtola
Teresa
T
Ruiz-Camps
Isabel
I
Abrisqueta
Pau
P
Llopart
Lluís
L
Marcos
María Ángeles
MÁ
Martínez
Miguel Julián
MJ
Tudó
Griselda
G
Bosch
Francesc
F
Pahissa
Albert
A
de Anta
María Teresa Jiménez
MT
Pumarola
Tomàs
T
D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D024882:Drug Resistance, Viral; D005838:Genotype; D006801:Humans; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy / Q000821:virology*; D008297:Male; D009305:Nasopharynx / Q000821:virology; D053139:Oseltamivir / Q000494:pharmacology / Q000627:therapeutic use*; D012367:RNA, Viral / Q000235:genetics; D012641:Selection, Genetic; D019562:Viral Load; D017201:Virus Shedding
D000998:Antiviral Agents; D012367:RNA, Viral; D053139:Oseltamivir