M G Semple1, J A Booth, B Ebrahimi. 1. Division of Child Health, School of Reproductive and Developmental Medicine, School of Infection and Host Defence, University of Liverpool, United Kingdom. m.g.semple@liv.ac.uk
Abstract
BACKGROUND: Nasopharyngeal secretions aspirated from infants with bronchiolitis (NPA) are a valuable resource for the study of virus dynamics and local inflammatory responses, however samples are small and difficult to manipulate. OBJECTIVES: To improve yield of NPA from infants. To establish if removal of the cellular component of NPA affects quantification of human metapneumovirus (hMPV) or human respiratory syncytial virus (hRSV) genome. STUDY DESIGN: Weight of NPA collected into traps from 30 infants was compared with that collected in trap plus catheter and washed through with saline from another 30 infants. hMPV (n=33) and hRSV (n=30) genome was measured by reverse-transcribed real-time polymerase chain reaction (RT-RT-PCR) in paired whole and cell-free NPA collected by the improved method. RESULTS: The improved method of NPA collection gave near two-fold greater weight (p = 0.002) of NPA (mean = 0.52 g (S.D. = 0.30 g)) than the traditional method (0.32 g (S.D. 0.19)). There was strong agreement and no significant difference between viral load measured in whole and cell-free fractions of NPA for both viruses (samples (n), correlation coefficient (cc) and significance (p)); hMPV (n=33, cc=0.938, p<0.001) and hRSV (n=30, cc=0.977 and p<0.001). CONCLUSIONS: The majority of hRSV and hMPV in nasal secretions is not associated with cells. Removal of the cellular component of NPA does not interfere with quantification of hRSV and hMPV.
BACKGROUND: Nasopharyngeal secretions aspirated from infants with bronchiolitis (NPA) are a valuable resource for the study of virus dynamics and local inflammatory responses, however samples are small and difficult to manipulate. OBJECTIVES: To improve yield of NPA from infants. To establish if removal of the cellular component of NPA affects quantification of human metapneumovirus (hMPV) or human respiratory syncytial virus (hRSV) genome. STUDY DESIGN: Weight of NPA collected into traps from 30 infants was compared with that collected in trap plus catheter and washed through with saline from another 30 infants. hMPV (n=33) and hRSV (n=30) genome was measured by reverse-transcribed real-time polymerase chain reaction (RT-RT-PCR) in paired whole and cell-free NPA collected by the improved method. RESULTS: The improved method of NPA collection gave near two-fold greater weight (p = 0.002) of NPA (mean = 0.52 g (S.D. = 0.30 g)) than the traditional method (0.32 g (S.D. 0.19)). There was strong agreement and no significant difference between viral load measured in whole and cell-free fractions of NPA for both viruses (samples (n), correlation coefficient (cc) and significance (p)); hMPV (n=33, cc=0.938, p<0.001) and hRSV (n=30, cc=0.977 and p<0.001). CONCLUSIONS: The majority of hRSV and hMPV in nasal secretions is not associated with cells. Removal of the cellular component of NPA does not interfere with quantification of hRSV and hMPV.
Authors: David W Fawkner-Corbett; Maria Carmo M B Duarte; Katie Rose; Angela Fonceca; Patricia Bezerra; Mark Hopkins; Murilo Britto; Luis E Cuevas; Jailson B Correia; Paul Stephen McNamara Journal: Pediatr Infect Dis J Date: 2012-06 Impact factor: 2.129
Authors: Patrícia G M Bezerra; Murilo C A Britto; Jailson B Correia; Maria do Carmo M B Duarte; Angela M Fonceca; Katie Rose; Mark J Hopkins; Luis E Cuevas; Paul S McNamara Journal: PLoS One Date: 2011-04-18 Impact factor: 3.240