Bacterial colonization in respiratory secretions from acute and recurrent wheezing infants and children

Abstract

Lower respiratory tract infection in childhood often results in airway obstruction, characterized by wheezing. However, contribution of bacterial colonization to the wheezy state in children remains unclear. Wheezing and non-wheezing children requiring hospitalization were classified into three groups: (i) wheezing children having a past history of recurrent wheezing; (ii) wheezing children without such history; and (iii) non-wheezing children as control subjects. Respiratory secretions as sputum were analyzed microscopically, and cultured. Cultured pathogenic bacterial species in sputum were categorized into two subgroups according to their amounts, i.e., dominant and non-dominant amounts of colonies. Incidence of bacterial colonization and wheezing were assessed. Hospitalized children were mainly 1- to 2-yr old, and rapidly decreased in number for older ages. Children in the three groups belonged to different clinical entities. Children in the recurrent wheezing group were highly sensitized to mite allergens, and still required hospitalization after 2 yr of age. Incidence of bacterial colonization was similar between the three groups. Dominant and non-dominant amounts of bacterial colonization were 170/997 (17.1%) and 170/997 (17.1%), respectively, in the recurrent wheezing group; 28/146 (19.2%) and 35/146 (24.0%), respectively, in the acute wheezing group; and 15/56 (26.8%) and 7/56 (12.5%), respectively, in the non-wheezing group. Regardless of the presence of wheezing, bacterial colonization commonly occurred at a young age in the three groups. In recurrent wheezing children, boys (122/611, 20.0%) carried non-dominant amounts of bacteria more frequently than girls (48/386, 12.4%) (p < 0.01). Boys showed predominant wheezing and susceptibility to bacterial colonization. Assessment of bacterial colonization allowed us to characterize asthma onset and outgrowth in childhood.

Nasopharyngeal bacterial colonization during the first wheezing episode is associated with longer duration of hospitalization and higher risk of relapse in young children

“…We did not find association to age, but other studies suggest that nasopharyngeal colonization of respiratory bacteria increase after birth and peak during early childhood, and then steadily decrease (6,13,23,24). Although there is variability in the peak age during childhood between studies, the nasopharyngeal colonization is much less during early adulthood compared to childhood (23,25).…”

“…In wheezing children, Nagayama et al (2007) reported the prevalence of 17% for S pne, H infl and M cat cultured from sputum samples (6). Serologic evidence for M pne infection has ranged from 4% to 23% and for C pne from 3% to 17% in children with acute wheezing (4,19,22).…”

“…Evidence of bacteria in the upper airways of children has been found using culture or serology in up to 40% of wheezing children (4)(5)(6). These have included Streptococcus pneumoniae (S Pne),…”

Le microbiome pulmonaire en 2015

“…À l'inverse, la colonisation par des bactéries sélectionnées serait un facteur de risque accru pour l'asthme. L'impact de la colonisation bactérienne sur l'asthme et sur la survenue d'exacerbations, a été observé dans de nombreuses études avec des taux de colonisation allant de 12 à 61 % selon les résultats [43][44][45] soit (mucoviscidose, BPCO, ou asthme), la survenue d'une exacerbation sera associée à une modification du bactériote et du bactériome, voire du mycobiote et/ou du virome [8,9,11,14,31,33,34]. Cette dysbiose, largement étudiée en ce qui concerne la communauté bactérienne, moins documentée pour les micromycètes, les virus ou les phages, montre clairement son impact sur la fonction respiratoire, sur la réponse inflammatoire et immune locale, voire une association avec une réponse incomplète au traitement adapté à la pathologie pulmonaire [23].…”

Pharyngeal Microflora Disruption by Antibiotics Promotes Airway Hyperresponsiveness after Respiratory Syncytial Virus Infection

“…In children with wheezing, bacterial colonization of the airway contains less dominant bacteria and more non-dominant bacteria than that of healthy children [9]. The pharyngeal microflora affects immune responses in surrounding lymphoid tissue.…”