High pneumococcal density correlates with more mucosal inflammation and reduced respiratory syncytial virus disease severity in infants

Abstract

BackgroundRespiratory syncytial virus (RSV) is an important cause of lower respiratory tract infections in infants. A small percentage of the infected infants develops a severe infection, while most of these severely ill patients were previously healthy. It remains unclear why these children develop severe RSV infections. In this study, we investigate whether pneumococcal nasopharyngeal carriage patterns correlate with mucosal inflammation and severity of disease.MethodsIn total, 105 infants hospitalized with RSV infection were included and recovery samples were taken from 42 patients. The presence and density of Streptococcus pneumoniae was determined by RT qPCR to study its relation to viral load, inflammation (MMP-9 and IL-6) and severity of RSV disease.ResultsWe show that pneumococcal presence or absence in the nasopharynx does not correlate with viral load, inflammation or severity of disease. However, when pneumococcus is present in patients, a higher nasopharyngeal pneumococcal density was correlated with a higher RSV load, higher MMP-9 levels and a less severe course of disease.ConclusionsOur results show correlations between S. pneumoniae density and viral load, inflammation and disease severity, suggesting that pneumococcal density may be an indicator for severity in paediatric RSV disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1454-x) contains supplementary material, which is available to authorized users.

Streptococcus pneumoniae colonization of the nasopharynx is associated with increased severity during respiratory syncytial virus infection in young children

“…RSV accounts for over three million paediatric hospitalizations per year . Outgrowth of bacteria known to asymptomatically colonize the upper airway of young children, including Streptococcus pneumoniae , Haemophilus influenzae and Moraxella catarrhalis , has been reported during viral ARI, often in association with increased disease severity . The contribution of viral/bacterial co‐infections to disease severity has been well‐documented in co‐infections caused by influenza viruses and S. pneumoniae in adults, however, the role of bacteria during paediatric viral ARI is less clear .…”

Corticotropin-releasing hormone improves survival in pneumococcal pneumonia by reducing pulmonary inflammation

“…; Pichichero and Almudevar ; Vissers et al. ). Therefore, studies were performed to correlate cellular immune responses against S. pneumoniae with survival given intranasal administration of CRH.…”

Clinical Efficacy of Pneumococcal Conjugate 13-valent Vaccine in Young Children

“…С дру-гой стороны, опубликованы результаты исследования об ассоциации вирусов с носительством пневмококков, гемофильной палочки типа В и др. [18,19]. Авторы связы-вают носительство данных бактерий с предрасположен-ностью к повторным ОРИ, отмечают снижение ОРИ при элиминации микроорганизмов и рассматривают соот-ветствующую вакцинацию как фактор, элиминирующий носительство микроорганизмов.…”