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.
Microbiology Department, Hospital Clínic and Barcelona Centre for International Health Research (CRESIB), Barcelona, Spain. ananton@clinic.ub.es
Andrés
A
Antón
Ana Alicia
AA
López-Iglesias
Teresa
T
Tórtola
Isabel
I
Ruiz-Camps
Pau
P
Abrisqueta
Lluís
L
Llopart
María Ángeles
MÁ
Marcos
Miguel Julián
MJ
Martínez
Griselda
G
Tudó
Francesc
F
Bosch
Albert
A
Pahissa
María Teresa Jiménez
MT
de Anta
Tomàs
T
Pumarola
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