Preventing otitis media and respiratory tract infections with the oral probiotic Streptococcus salivarius K12

Acute otitis media (AOM) and respiratory tract infections are common in early childhood and are major contributors to antibiotic use. The oral probiotic Streptococcus salivarius K12 has demonstrated antimicrobial and immunomodulatory activity in vitro, and preventive effects in children with recurrent AOM. We aim to determine the efficacy of S. salivarius K12 in preventing AOM in the general infant population. We conducted a multicentre, double-blind, randomised, placebo-controlled trial in Wellington and Christchurch, New Zealand. Children were enrolled at 3-6 months of age, their households were randomised 1:1, and daily study product was given from age 6 to 24 months. The primary outcome was the rate of doctor-recorded AOM. Secondary outcomes included time to first AOM episode, respiratory infections, antibiotic prescribing and healthcare utilisation. Analyses were by intention to treat using mixed-effects negative binomial regression adjusted for region and, for the primary outcome, prior AOM, with random effects for general practice and family. A total of 428 children were randomised by household and 368 (86%) contributed primary outcome data (placebo n = 180; active n = 188). Doctor-recorded AOM occurred in 70/180 (39%) placebo recipients and 70/188 (37%) probiotic recipients (rate ratio 0.84, 95% CI 0.57-1.24). Time to first AOM episode did not significantly differ (hazard ratio 0.89, 95% CI 0.63-1.26). No significant differences were observed for AOM severity, respiratory infections, antibiotic prescribing or healthcare utilisation. Higher-adherence analyses were also not statistically significant.

Daily oral S. salivarius K12 did not reduce AOM incidence or respiratory infections in children under 2 years; therefore, routine use for AOM prevention in general paediatric populations is not supported.

Australian New Zealand Clinical Trials Registry-ACTRN12618000130268; prospectively registered on 30 January 2018, before enrolment of the first participant on 24 August 2018.

• Streptococcus salivarius K12 is a naturally occurring oral probiotic and has demonstrated antimicrobial and immunomodulatory activity in vitro, and preventive effects in children with recurrent AOM.

•  Whether there are preventative effects of daily use for AOM and respiratory infections in infants from the general population.