COME in preschool-aged children

A recent study found that pathogen exposure, upper respiratory tract infection (URI), and nasal obstruction all were associated with chronic otitis media with effusion (COME) in preschool-aged children, underscoring the need for improved methods in pathogen transmission prevention in this patient population.

“Chronic otitis media with effusion is very common but also very complex as it involves many risk factors and can have serious consequences. There may not be any magic bullet. However, measures that promote healthy immunity and reduce pathogen exposure are reasonable strategies that will also be beneficial for other infectious conditions,” says Rebecca E. Walker, medical researcher, Department of Paediatrics, Child and Youth Health, University of Auckland, New Zealand.

Walker and colleagues recently conducted a study in preschool-aged children trying to determine the risk factors of COME in this patient population. The case-control design study included children aged 3 to 4 years who were referred for tympanostomy tube placement because of a diagnosis of COME (n=178), and a control group comprised of a random sample of healthy children aged 3 to 4 years from primary care practices (n=209). Detailed information on various topics including sociodemographic information, pregnancy and birth, infant feeding practices, home environment, and respiratory health was collected from the children’s guardians through interview-administered questionnaires. The risk of COME independently associated with the exposures was calculated.

The researchers found that children with COME frequently had nasal obstruction; always snored or often snored; spent more hours per week in daycare; had frequent colds; had siblings who had undergone tympanostomy tube replacement; underwent long labor; and had early introduction of cow’s milk. Interestingly, Asian ethnicity and having older siblings were inversely associated with COME.

“It is thought that bacterial biofilms in the nose and nasopharynx are an important factor connecting nasal obstruction, snoring, and COME,” Walker says. “Although more research needs to be done, researchers largely agree on the importance of bacterial biofilms in the middle ear in otitis media, and there is a lot of good evidence to support this theory,” she notes.

According to Walker, bacterial biofilm communities are highly resistant to treatment. Biofilms encase themselves in a slimy extracellular matrix that protects them from host immune response and antimicrobial treatment. Therefore, biofilms are often involved in chronic or recurring infections because they can remain relatively dormant but then “flare up” and cause acute conditions when they disperse free-moving planktonic bacteria.

“This may explain why COME and recurrent acute otitis media (RAOM) are highly correlated. In the case of COME, the association with biofilms provides an explanation for why treatment with antibiotics is often ineffective despite bacteria being strongly implicated,” Walker says.

The study found that long labor and the early introduction of cow’s milk could play a role in the development of COME, raising further questions about the extent these factors could influence disease development, as well as potential solutions to help circumvent morbidity here.

“Although the results need to be replicated in future studies, it is possible that cow’s milk introduction too early may alter a child’s microbiota and may lend itself to more pathogen colonization. HoweLikewise, having a prolonged labor indicates that it could be a result of a difficult birth, where prophylactic antibiotics were given due to the mother having a fever or baby needing intensive care treatment,” Walker says.

Antibiotics will disrupt a baby’s microbiota, and this may explain the study’s findings. According to Walker, allowing the child to establish and maintain a healthy commensal bacterial community helps to prevent pathogen colonization by occupying the host’s microbial niches with helpful or neutral bacteria that resist invasion by other species or strains.

“Having an established healthy core microbiome may stop pathogens getting a foothold in niches. If we can understand what bacteria make up a healthy airway microbiota and promote them in children from birth, we may help in preventing otopathogen colonization,” she says.

Controlled trials of the effects of vitamin D supplementation on COME also may be worthwhile, as there is evidence that it can help reduce RAOM. Vitamin D may help to promote an effective but less inflammatory immune response,” Walker adds. 

Dr Petrou is a freelance medical writer based in Budapest, Hungary.