CULTURE AND MOLECULAR ANALYSIS OF MICROBIAL COMPONENTS OF THE HUMAN OUTER EAR IN THE HEALTY, INFLAMED AND HEARING AID USERS

The ear canal is an important ecological niches that is colonized by microorganisms that are still to characterize. The use of hearing aids is a predisposing factor to develop acute otitis externa and microorganisms responsible are poorly identified. The aim of this study was to determine microbial communities in the human ear canal and to identify specific bacterial communities that may be associated with otitis, in individuals wearing hearing aids or not. A total of 115 samples, 56 ear swabs and 59 hearing aids, fit open and closed, were collected. Microorganisms were identified by conventional phenotypic systems and by 16S rDNA gene sequence analysis. All samples with a high bacterial load had a polymicrobial profile, suggesting a possible synergy among different bacterial species. Coagulase negative staphylococci were the most frequent microbial isolates. Pathogens, such as Staphylococcus aureus, Streptococcus agalactiae, and opportunist, such as Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Corynebacterium pseudodiftericum, Corynebacterium afermentans, Bacillus spp., and Enterococcus faecalis were also recovered. This study describes the microorganisms retrieved from canal ear and hearing aid (HA). With the exception of coagulase negative staphylococci, each HA analyzed reflected a unique, varied and mostly polymicrobial bacterial composition, deeply different from non HA users.