RESUMO
BACKGROUND: Nucleic acid amplification tests (NAATs), such as PCR, are preferred for respiratory virus testing, due to superior diagnostic accuracy and faster turnaround time. Panther Fusion® Respiratory Assays (Fusion), which includes FluA/B/RSV (FFABR), Paraflu and AdV/hMPV/RV, offers a modular approach to syndromic testing on a fully automated platform while improving gene targets and expanding the test menu. OBJECTIVES AND STUDY DESIGN: We evaluated Fusion using 275 consecutive nasopharyngeal specimens previously used in an analysis of five PCRs, as well as 225 archived specimens. RESULTS: Of the combined 500 specimens, 134 were positive for influenza A (FluA), 54 for FluB, 65 for RSV, 64 for parainfluenza (PIV), 24 for adenovirus (AdV), 21 for humanmetapneumovirus (hMPV), and 40 for rhinovirus (RV) with Fusion. Of the positive samples Fusion correlated with historical results for all but one, despite multiple freeze-thaws cycles of this collection. Fusion was positive for an additional 33 samples, including 11 FluAs, 7 RSVs, 3 PIV3s, 3 AdV, 6 hMPV and 3 RVs. These samples were retested with corresponding Prodesse (Pro) assays using quadruple sample volume. This resolver test confirmed Fusion results for an additional 4 FluAs, 4 RSVs, 1 PIV3 and 3 AdVs. The sensitivity and specificity ranges of Fusion were 99-100% and 98-100%. Limit of detection (LOD) analyses were performed on a variety of Flu isolates. The LODs ranged from 2.69 to 2.99 log copies/ml and demonstrated superior LOD as compared to previously published data for some assays or to concurrent analyses with two new commercial tests.
Assuntos
Técnicas de Amplificação de Ácido Nucleico/métodos , Infecções Respiratórias/diagnóstico , Viroses/diagnóstico , Vírus/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Automação Laboratorial , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Infecções Respiratórias/virologia , Sensibilidade e Especificidade , Viroses/virologia , Adulto JovemRESUMO
BACKGROUND: Nucleic acid amplification assays have become the method of choice for influenza (Flu) testing due to superior accuracy and faster turnaround time. Although assays are designed to detect highly conserved genomic targets, mutations can influence test sensitivity. Most of the circulating viruses in the United States during the 2014-2015 season were associated with significant genetic drift; however, the effect on testing was unknown. OBJECTIVES AND STUDY DESIGN: We compared the performance of Prodesse ProFlu+/ProFAST+ (PFlu/PFAST), FilmArray Respiratory Panel (RP), cobas® Influenza A/B test (cIAB), and Xpert® Flu (Xpt) in a retrospective analysis of consecutive nasopharyngeal specimens received for a two-week period during the winter of 2015. Furthermore, limits of detection (LOD) were determined with six isolates of Flu. RESULTS: Of the 275 specimens, 63 were positive for FluA by PFAST, 60 were positive by RP, 58 were positive by cIAB and 52 were positive by Xpt. Only a subset of 135 specimens was tested by PFlu, of which 32 were positive. The sensitivity/specificity for PFAST, RP, cIAB, Xpt and PFlu was 100/99.1%, 96.7/99.5%, 91.8/99.1%, 85.2%/100%, and 75.6%/98.9%, respectively. LOD analyses demonstrated assay performance variations were strain associated. Specifically, PFlu's and cIAB's LODs were higher with A/Texas/50/2012-like and A/Switzerland/9715293/2013-like strains, while Xpt's highest LOD was with the Swiss strain. CONCLUSIONS: Strain-associated assay performance variation is known to occur with other Flu test methods; hence, it is not surprising that such variation would be observed with molecular tests. Careful monitoring and reporting for strain-associated variances are warranted for all test methods.
Assuntos
Vírus da Influenza A/genética , Vírus da Influenza B/genética , Influenza Humana/diagnóstico , Sequência de Bases , Evolução Molecular , Deriva Genética , Genoma Viral , Humanos , Influenza Humana/virologia , Limite de Detecção , Técnicas de Diagnóstico Molecular , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Análise de Sequência de DNA , Estados Unidos , Carga ViralRESUMO
Palivizumab is a humanized monoclonal antibody used to decrease the threat of respiratory syncytial virus (RSV) infection among children at high risk. There are no standard guidelines due to conflicting data on palivizumab's use in the treatment of RSV lower respiratory tract infections. Intravenous (IV) palivizumab was shown to be well tolerated and associated with decreased mortality in high-risk children who have RSV disease. However, it did not prevent lower respiratory tract infections and did not affect the survival rate of allogeneic stem cell transplant recipients who had RSV infection. We present 2 children with acute lymphocytic leukemia (ALL) and persistent RSV infection while receiving chemotherapy. Patient A is a 4-year-old male with Down syndrome, ALL, and persistent RSV infection for at least 3 months. Patient B is a 3-year-old female with pre-B cell ALL whose chemotherapy intensification phase was delayed due to a month-long RSV infection. RSV infections were determined by using real-time polymerase chain reaction assays from nasopharyngeal swabs before IV palivizumab therapy; patient A was positive for RSV at 36 cycles and patient B was positive for RSV at 29 cycles. RSV infection was cleared in both patients within 72 hours after receiving IV palivizumab (patient A: 16 mg/kg; patient B: 15 mg/kg). IV palivizumab may be a treatment option for persistent RSV infection among immunocompromised patients.
