Gut Resistome and Hearing Loss in Young Adults: A Preliminary Study on the Interplay Between Microbial Resistance and Auditory Health

Background: Hearing loss (HL) affects more than 1.5 billion people worldwide and represents a major global health concern. Recent evidence suggests that alterations in gut microbial composition and antimicrobial resistance (AMR) may be linked to inflammatory and metabolic pathways that could influence auditory physiology. Objectives: This study aimed to explore the relationship between auditory function and the antimicrobial resistance in the gut microbiome of young adults. Methods: Fecal and auditory data were collected from young adults. Auditory function was assessed through pure-tone audiometry, and participants were classified according to the presence or absence of HL based on the American Speech-Language-Hearing Association (ASHA) criteria. Bacterial resistance was analyzed under aerobic and anaerobic conditions using disk diffusion and E-test methods to determine minimum inhibitory concentrations (MICs) for a panel of antibiotics. Gut microbiota composition was further characterized using quantitative polymerase chain reaction (qPCR) to quantify 15 key microbial taxa. Results: Overall, 40.9% of participants presented some degree of HL, with mild or slight HL being more frequent in women (53.3%) than in men (14.3%). Participants with HL exhibited significantly higher MICs for nalidixic acid, amoxicillin, and ciprofloxacin, as well as trends toward increased MIC variability for several other agents. Principal component analysis demonstrated distinct clustering of individuals without HL and greater dispersion among those with HL, suggesting higher interindividual variability in resistance profiles. These findings suggest potential associations between antimicrobial resistance and auditory function, possibly mediated through gut microbiome alterations. qPCR analyses demonstrated that Faecalibacterium prausnitzii abundance was significantly higher in individuals with HL and in those exhibiting greater resistance to amoxicillin. Conclusions: These findings provide preliminary evidence connecting the gut resistome with auditory function, supporting the emerging concept of a gut–ear–brain axis and underscoring the need for further research into microbiome-related mechanisms underlying HL.