Effect of probiotic lozenges on improvement in tympanometric classification within 12 weeks in children aged 3-6 years with adenoid hypertrophy and otitis media with effusion undergoing non-surgical management: a randomized controlled trial.

BACKGROUND

Otitis media with effusion (OME) is common among children aged 3-6 years with adenoid hypertrophy. Restoring middle-ear ventilation and clearing effusion are key goals during non-surgical management, and tympanogram classification serves as the main clinical indicator. The probiotic Streptococcus salivarius K12 (SSK12) can colonize the upper airway and inhibit pathogens, yet randomized trials using tympanogram classification as the primary endpoint are limited.

OBJECTIVE

This study aimed to evaluate the effect of daily SSK12 lozenges (≥1×10⁹ CFU) for 12 weeks on tympanogram classification improvement in children with adenoid hypertrophy and OME and to elucidate related microecological, pathogenetic, and audiological pathways, along with safety and internal validity measures.

METHODS

A single-center, randomized, double-blind, placebo-controlled RCT was conducted. All participants received standard non-surgical management and were allocated to either SSK12 or placebo lozenges for 12 weeks. The primary outcome was child-level tympanogram improvement ("B/C→A") at week 12. Secondary analyses included ear-level results, tympanometric parameter changes, audiometric outcomes, and nasopharyngeal microbiota profiles. Logistic regression, generalized estimating equations (GEE), and linear mixed-effects models were employed to estimate adjusted odds ratios (aORs), interaction terms, and time effects.

RESULTS

Compared with placebo, SSK12 significantly increased the probability of tympanogram improvement (aOR=1.87, P = 0.003), with consistent benefits across subgroups (all p(interaction)>0.05). Ear-level analyses confirmed the advantage (all aOR>1, P<0.05), with moderate intra-child correlation (ρ≈0.33). SSK12 produced significant group × time interactions for tympanometric parameters-positive changes in ΔTPP and ΔYtm and decreased ΔTW (all P<0.01). Microbiological analyses demonstrated a marked increase in SSK12 colonization (both rate and load, P<0.001) and reduced loads of H. influenzae, S. pneumoniae, and M. catarrhalis (all P<0.01). Audiological outcomes improved, including greater decline in four-frequency pure-tone average (P = 0.002) and higher DPOAE conversion (aOR=2.06, P = 0.001). Incidences of upper respiratory infections and acute otitis media were reduced (both P<0.05). No significant adverse effects or blinding bias were observed.

CONCLUSION

Daily SSK12 lozenges for 12 weeks significantly improved tympanogram classification and auditory function, mediated by enhanced probiotic colonization and pathogen suppression, with excellent safety and adherence. SSK12 represents a low-risk, biologically rational adjunct in the conservative management of pediatric OME associated with adenoid hypertrophy.

Copyright © 2026 Shi, Liu, Chen, Hou, Chen, Chen and Li.