Quantitative analysis of XXXX (H3N2) @entity43739 and @entity39723 variants in clinical specimens by real-time reverse transcription polymerase chain reaction.

@entity689 @entity39723 @entity1 @entity684 @entity685 @entity43739 @entity683
BACKGROUND: Because @entity683 virus isolates after cell culture are required to determine their susceptibility to @entity689 inhibitors, the differences in normal or low-susceptibility variant population frequencies between clinical samples and isolates have not been considered. OBJECTIVES: To identify variations in low-susceptibility populations in clinical samples after initiation of @entity684 and @entity685 therapy by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). STUDY DESIGN: We measured the populations of the low-susceptibility @entity683 H3N2 variants @entity43739 and @entity39723 by qRT-PCR using 305 nasal aspiration samples collected over time from 13, 16, and 11 @entity1 treated with no @entity689 inhibitors, @entity684 , and @entity685 , respectively. The variant population in the isolates was also determined when the population of low-susceptibility variants in the clinical samples increased following treatment. Moreover, the susceptibility of all isolates was measured. RESULTS: The @entity43739 variant was detected in only one @entity1 during @entity684 therapy, exhibiting decreased susceptibility to @entity684 . Prior to treatment, @entity39723 variants were detected in all clinical samples; however, they comprised only a small fraction of the total population. The proportion of the @entity39723 variant in clinical samples increased for 6/27 (22.2%) @entity1 treated with @entity684 or @entity685 , whereas an increase in the proportion of the @entity39723 variant in virus isolates was observed in only one @entity1 . CONCLUSIONS: Discrepancies in the proportion of @entity39723 variants between clinical samples and isolates should be suspected in clinical settings. qRT-PCR is useful for quantitative analysis of drug-resistant @entity683 virus and for immediate notification of the result.
