ABSTRACT
Alloiococcus otitidis is a recently discovered bacterium frequently associated with otitis media. However, no study is available as to whether A. otitidis has a pathogenic role and induces local immune response in the middle ear as a true pathogen. Whole bacterial sonicate of A. otitidis was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and transferred to a nitrocellulose membrane. Then, Western blot analysis was performed with supernatant of the middle ear effusions from children with A. otitidis-positive otitis media. SDS-PAGE of the bacterial sonicate showed several protein bands, designated A1-A11. Western blot analysis revealed the presence of IgG, secretory IgA, IgG2, and IgM against A. otitidis in the middle ear effusions. Absorption of the specimens with sonicates of other major middle ear pathogens did not alter the reactivity of antibodies against the alloiococcal antigens. The results suggest that specific local immune response against A. otitidis is induced during middle ear infection of the organism as a true pathogen. A5, A6 or A11 is expected to be a main antigenic determinant. This is the first report to show evidence of local antibody response against A. otitidis and to disclose antigenic components of A. otitidis.
Subject(s)
Antibodies, Bacterial/biosynthesis , Ear, Middle/immunology , Gram-Positive Bacterial Infections/immunology , Gram-Positive Cocci/immunology , Otitis Media/immunology , Otitis Media/microbiology , Antibodies, Bacterial/immunology , Child , Child, Preschool , Ear, Middle/microbiology , Electrophoresis, Polyacrylamide Gel , Female , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Cocci/chemistry , Humans , Immunoglobulin Isotypes/biosynthesis , Immunoglobulin Isotypes/immunology , Male , SonicationABSTRACT
Acute otitis media (AOM) and otitis media with effusion (OME) are common diseases in childhood. Alloiococcus otitidis is a newly recognized species of gram-positive bacterium which was recently discovered as a pathogen associated with OME. Although some studies show that A. otitidis is frequently detected in children with OME, no study is available concerning the clinical efficiency of antibiotics against this organism. The prevalence of A. otitidis in 116 middle ear effusion specimens from 36 AOM and 52 OME patients was examined by culture and PCR. In addition, the prevalence of the bacterium was retrospectively investigated in relation to antibiotic use. A. otitidis was detected in 20 (50%) AOM and 47 (61%) OME specimens. The organism was the most frequent bacterium in AOM as well as in OME and was highly detected even in patients who had been treated with antibiotics, such as beta-lactams or erythromycin. The incidence of A. otitidis in our study was higher than that in Western countries, and our results suggest that drug-resistant strains of A. otitidis may be frequently spread in Japanese children. Our study suggests that antibiotics such as beta-lactams or erythromycin may not be sufficiently effective to eliminate this organism. Further investigation is expected to reveal the clinical role of the organism in otitis media.
Subject(s)
Gram-Positive Bacterial Infections/microbiology , Gram-Positive Cocci/isolation & purification , Otitis Media/microbiology , Acute Disease , Anti-Bacterial Agents/therapeutic use , Bacteriological Techniques , Child , Child, Preschool , Female , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Cocci/genetics , Gram-Positive Cocci/pathogenicity , Humans , Infant , Male , Otitis Media/drug therapy , Otitis Media with Effusion/drug therapy , Otitis Media with Effusion/microbiology , Polymerase Chain ReactionABSTRACT
OBJECTIVE: Colonization of middle ear pathogens is facilitated in the nasopharynx of otitis-prone children, and is associated with the development of otitis media. Recently, a new species of bacterium, Alloiococcus otitidis, is considered as one of the major middle ear pathogens. However, as far as we know, no study has been reported concerning the prevalence of A. otitidis in the nasopharynx of otitis-prone children. And, no study has been conducted on the association of A. otitidis in the nasopharynx with otitis media. METHODS: The frequency of A. otitidis in 83 middle ear effusions (MEE) and 56 nasopharyngeal swab (NPS) specimens from 56 children with otitis media was investigated by culture and polymerase chain reaction (PCR). RESULTS: A. otitidis was detected in 24 (28.9%) of MEE and in 6 (10.7%) of NPS specimens. When the frequency was investigated in relation to proneness to otitis media, A. otitidis was detected in 16 (64%) of 25 MEE and in 5 (29.4%) of 17 NPS specimens from otitis-prone children, whereas it was detected in 8 (13.8%) of 58 MEE and in 1 (2.6%) of 39 NPS specimens from non-otitis-prone children. The frequency of A. otitidis in both NPS and MEE specimens was significantly higher in otitis-prone than in non-otitis-prone children. CONCLUSIONS: Our results suggest that colonization of A. otitidis is facilitated in the nasopharynx of otitis-prone children. And, nasopharyngeal colonization of A. otitidis may be associated with the frequency of otitis media.
