Childhood Wheezing Illness Risk Modified by Lactobacillus Microbiome in RSV

Nasopharyngeal detection and increased abundance of Lactobacillus during acute respiratory infection (ARI) with respiratory syncytial virus (RSV) in infancy are associated with a decreased risk for childhood wheezing illnesses at 2 years of age, according to the results of a study published in the Journal of Allergy and Clinical Immunology.

In a population-based nested cohort study, Infant Susceptibility to Pulmonary Infections and Asthma Following RSV Exposure (INSPIRE), the investigators sought to examine the role of the nasopharyngeal microbiome in the development of subsequent childhood wheezing illnesses following the occurrence of RSV ARI in infancy. Previously healthy term infants who were born between June and December were evaluated in order to study the first RSV episode that occurred during infancy.

A total of 118 infants with confirmed RSV ARI were enrolled in the study. Median patient age at the time of RSV ARI occurrence was 21.8 weeks (range, 12.1 to 27.1). There were 125 nasal washes involved, since 5 infants experienced 2 episodes of RSV ARI and 1 infant experienced 3 episodes. The group of 118 newborns represented a nested cohort with nasopharyngeal microbiome assessment during a confirmed RSV ARI episode and available 2-year data. RSV detection was performed with the use of real-time reverse transcription polymerase chain reaction.

Overall, 95.8% (113 of 118) of the infants evaluated had 2-year outcome data available. Of these newborns, 40.7% (46 of 113) had parental reports of later wheeze and 31.9% (36 of 113) had parental reports of recurrent wheeze.

No association was demonstrated between the overall taxonomic composition, diversity, and richness of the nasopharyngeal microbiome during an RSV ARI episode with the development of subsequent wheezing illnesses in childhood. The nasopharyngeal detection and abundance of Lactobacillus, however, was consistently higher in infants who did not develop later wheezing illnesses.

The overall taxonomic composition of the nasopharyngeal microbiome during RSV ARI episodes in infancy was associated with a high relative abundance of Moraxella (37.6%), Streptococcus (19.7%), Haemophilus (13.5%), Corynebacterium (10.0%), and Dolosigranulum (4.7%), and a low relative abundance of the remaining bacterial genera (combined relative abundance of 14.5%).

The genus Lactobacillus was detected in 31.2% (39 of 125) of the samples, with the proportion of samples with this genus being lower in infants with subsequent wheezing illnesses compared with infants without (26% vs 49%, respectively). In a multivariable model adjusted for age, gender, maternal asthma, and early-life exposure to antibiotics, the detection of Lactobacillus decreased the likelihood of subsequent wheeze by approximately 70% (odds ratio [OR], 0.34; 95% CI, 0.14-0.83; P =.02) and of recurrent wheeze by approximately 80% (OR, 0.21; 95% CI, 0.07-0.65; P =.006).

The investigators concluded that although these preliminary findings warrant replication in larger longitudinal studies, the novel data may help to support the development of new prognostic or preventive strategies for childhood wheezing illnesses.

Reference

Rosas-Salazar C, Shilts MH, Tovchigrechko A, et al. Nasopharyngeal Lactobacillus is associated with childhood wheezing illnesses following acute respiratory syncytial virus infection in infancy [published online January 9, 2018]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2017.10.049