Ear Infections

Why some children get ear infection after ear infection

Ear infections are the most common bacterial infection in young children and the leading reason for antibiotic prescriptions in that age group. Around 70% of infants have at least one episode by age 2, and 20% to 30% go on to develop the recurrent form this article focuses on. A study tracking nasal swabs from 58 children over a year found that recent antibiotic use was linked to more disease-causing bacteria and a higher rate of new ear infections, while more mature, balanced microbiomes were linked to fewer infections. This points to a cycle: an infection leads to antibiotics, antibiotics disrupt the microbiome, and a disrupted microbiome makes the next infection more likely.

Source: PMC, Age and antibiotic use influence longitudinal dynamics of the upper respiratory microbiome in children with recurrent acute otitis media

A probiotic trial breaking that cycle

Researchers identified a specific probiotic strain, Lactobacillus salivarius PS7, chosen for its strong activity against the bacteria that cause ear infections. In a trial involving 61 children with recurrent ear infections, daily use of this strain for 6 months led to an 84% reduction in the number of infection episodes, compared with the same children's infection history in the 6 months beforehand. A separate observational study comparing 16 children with recurrent infections to 19 healthy children found real differences in gut bacteria composition between the two groups, adding further support to the connection.

It's important to be honest that not every probiotic strain works this well. A separate, more rigorous placebo-controlled trial tested a different strain, Streptococcus salivarius K12. It did reduce the levels of infection-causing bacteria in the nose and throat, but this didn't translate into fewer actual ear infections, 8.2% of the probiotic group developed an infection needing antibiotics, compared with 5.8% on placebo, not a meaningful difference. This shows that reducing harmful bacteria in a lab measurement doesn't always translate into a real-world benefit, and the specific strain used clearly matters. Part of the reason may be that adding a probiotic only introduces bacteria, it doesn't guarantee they'll actually establish themselves. Like bringing new animals into a zoo, arrival isn't enough, they need a steady food supply to survive and multiply, otherwise they simply die back out without ever changing the underlying balance.

Source: PMC, Prevention of Recurrent Acute Otitis Media in Children Through the Use of Lactobacillus salivarius PS7

Source: Folia Microbiologica, Gut microbiota composition in recurrent acute otitis media

Source: Contemporary Pediatrics, Probiotic trial with Streptococcus salivarius falls short in preventing acute otitis media

Feeding shapes this risk from day one

The earliest evidence for a gut connection here comes from infant feeding itself. Exclusively breastfed infants have been found to have around 50% fewer episodes of ear infections than infants who are exclusively formula-fed. Researchers believe this is largely because human milk promotes the growth of Lactobacillus and Bifidobacterium in the infant gut, the same protective bacteria groups that show up throughout this research, and these bacteria help create a more acidic gut environment that's harder for harmful bacteria to survive in.

Source: The relationship between breastfeeding and reported respiratory and gastrointestinal infection rates in young children

What this means for you

Ear infections need proper diagnosis, and antibiotics remain appropriate when a doctor prescribes them, but repeated rounds are worth discussing further with a paediatrician given this research, particularly since the specific probiotic strain used appears to matter a great deal. Supporting the gut microbiome with a varied, plant-rich diet, and asking a doctor whether a specific probiotic strain is appropriate for a child with recurrent infections, are both reasonable steps. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.