Bacteria in dust of daycare centers linked to likelihood for childhood wheeze

Key takeaways:

• The odds for wheeze increased among children attending daycares with Streptococcus and Lactococcus bacteria.
• More research is required on dust microbiota composition in daycare centers.

Children attending daycare centers with a dust microbiota profile of Streptococcus and Lactococcus faced an increased likelihood for wheezing, according to a presentation at the European Respiratory Society International Congress.

Annabelle Bédard

“Daycare attendance can have a dual role in asthma,” Annabelle Bédard, PhD, MSc, postdoctoral researcher at Inserm (the French National Institute of Health and Medical Research), told Healio. “Indeed, while it is an environment rich in microbes, which appears to be essential in acquiring adaptive and regulated immune system responses to other environmental elements (such as allergens, particles and viruses), it also increases the risk of viral respiratory infections in early life, associated with greater risk of wheezing and asthma later in childhood.

“Like other environments, the dust microbiome in daycare centers is composed of many different bacteria that may have both protective or deleterious effects,” she added. “We now know that it is more a balance or an imbalance between the different bacteria found in an environment that plays a role in health (and not the effect of a few specific bacteria). Nonetheless, our findings are consistent with a study in Finnish children, which reported that a higher abundance of the Lactococcus genus in household floor dust was associated with an increased risk of asthma at age 10 years.”

Using the French CRESPI cohort (Respiratory Health of Children in Daycare), Bédard and colleagues analyzed 103 daycare center floor dust samples to determine if dust microbiota composition — described by 16S rRNA gene sequencing, with a clustering approach used to create four dust microbiota profiles — impacts childhood wheezing.

Researchers also used questionnaires completed by the parents/guardians of the children (n = 515; mean age, 22 months) to assess ever and recurrent wheezing.

More than half of the daycare centers (n = 55) had a microbiota profile containing Streptococcus, Neisseria and Haemophilus, and this acted as the reference group. Twenty-one centers had dust that contained Streptococcus and Lactococcus, nineteen were described as “mixed with Streptococcus” and eight had microbiota profiles classified as “mixed with rare (relative abundance < 1%) taxa.

Of the total cohort, 32% of parents reported that their child had ever wheezing and 13% reported recurrent wheezing. Also, 11% had wheeze that impacted daily activities and/or sleep and 19% had used inhaled corticosteroids or emergency care/hospitalization for wheeze.

When evaluating each of the dust profiles in relation to wheezing compared with the reference group, researchers observed greater odds for recurrent wheezing in the daycare centers with Streptococcus and Lactococcus following adjustment for age and number of children per center.

Also, children attending daycare centers within the “mixed with Streptococcus” profile showed increased risk for recurrent wheeze as well as wheeze that impacted daily activities or sleep.

“Although our results suggest that the composition of dust microbiota in daycare is associated with the risk of wheezing in early childhood, these results are preliminary and need to be confirmed in other studies,” Bédard told Healio. “Moreover, we need to conduct more research to identify the determinants of dust microbiota composition in the daycare centers such as building characteristics, ventilation, cleaning practices, etc. We need to investigate how they affect the composition of dust microbiota and how they can modulate the association between the composition of dust microbiota and respiratory health in children.

“These and future findings from other studies could help direct public health intervention strategies for asthma prevention,” Bédard added.

Reference:

• Study of bacteria in day care settings reveal links with children’s lung health. https://www.ersnet.org/news-and-features/news/study-of-bacteria-in-day-care-settings-reveals-links-with-childrens-lung-health/. Published Sept. 12, 2023. Accessed Sept. 12, 2023.