The clinical role of Alloiococcus otitidis in otitis media with effusion

Alloiococcus otitidis-Cause of Nonspecific Acute Sinusitis: First Case Report and Review of Literature

Although most sinus infections are viral, potential bacterial pathogens such as Streptococcus pneumoniae, Haemophilus influenza and Moraxella catarrhalis can migrate during a viral respiratory infection from the nasopharynx into the sinus cavity causing sinusitis. Alloiococcus otitidis is a commensal of the external auditory canal and is considered one of the potential middle ear pathogens. Unlike most otopathogens, A. otitidis is rarely found in the nasopharynx of healthy individuals. This difficult-to-culture organism has not previously been described as a causative agent of sinusitis. Here we describe one case of acute sinusitis due to A. otitidis and review previous knowledge of this controversial organism based on recent literature.

Effects of nasopharyngeal microbiota in respiratory infections and allergies

The human microbiome, which consists of a collective cluster of commensal, symbiotic, and pathogenic microorganisms living in the human body, plays a key role in host health and immunity. The human nasal cavity harbors commensal bacteria that suppress the colonization of opportunistic pathogens. However, dysbiosis of the nasal microbial community is associated with many diseases, such as acute respiratory infections including otitis media, sinusitis and bronchitis and allergic respiratory diseases including asthma. The nasopharyngeal acquisition of pneumococcus, which exists as a pathobiont in the nasal cavity, is the initial step in virtually all pneumococcal diseases. Although the factors influencing nasal colonization and elimination are not fully understood, the adhesion of opportunistic pathogens to nasopharyngeal mucosa receptors and the eliciting of immune responses in the host are implicated in addition to bacterial microbiota properties and colonization resistance dynamics. Probiotics or synbiotic interventions may show promising and effective roles in the adjunctive treatment of dysbiosis; however, more studies are needed to characterize how these interventions can be applied in clinical practice in the future.

Reviewing the Pathogenic Potential of the Otitis-Associated Bacteria Alloiococcus otitidis and Turicella otitidis

Alloiococcus otitidis and Turicella otitidis are common bacteria of the human ear. They have frequently been isolated from the middle ear of children with otitis media (OM), though their potential role in this disease remains unclear and confounded due to their presence as commensal inhabitants of the external auditory canal. In this review, we summarize the current literature on these organisms with an emphasis on their role in OM. Much of the literature focuses on the presence and abundance of these organisms, and little work has been done to explore their activity in the middle ear. We find there is currently insufficient evidence available to determine whether these organisms are pathogens, commensals or contribute indirectly to the pathogenesis of OM. However, building on the knowledge currently available, we suggest future approaches aimed at providing stronger evidence to determine whether A. otitidis and T. otitidis are involved in the pathogenesis of OM. Such evidence will increase our understanding of the microbial risk factors contributing to OM and may lead to novel treatment approaches for severe and recurrent disease.

Microbiology of otitis media in Indigenous Australian children: review

Objectives:

To review research addressing the polymicrobial aetiology of otitis media in Indigenous Australian children in order to identify research gaps and inform best practice in effective prevention strategies and therapeutic interventions.

Methods:

Literature review.

Results:

Studies of aspirated middle-ear fluid represented a minor component of the literature reviewed. Most studies relied upon specimens from middle-ear discharge or the nasopharynx. Culture-based middle-ear discharge studies have found that non-typeableHaemophilus influenzaeandStreptococcus pneumoniaepredominate, withMoraxella catarrhalis, Staphylococcus aureusandStreptococcus pyogenesisolated in a lower proportion of samples.Alloiococcus otitidiswas detected in a number of studies; however, its role in otitis media pathogenesis remains controversial. Nasopharyngeal colonisation is a risk factor for otitis media in Indigenous infants, and bacterial load of otopathogens in the nasopharynx can predict the ear state of Indigenous children.

Conclusion:

Most studies have used culture-based methods and specimens from middle-ear discharge or the nasopharynx. Findings from these studies are consistent with international literature, but reliance on culture may incorrectly characterise the microbiology of this condition. Advances in genomic technologies are now providing microbiologists with the ability to analyse the entire mixed bacterial communities (‘microbiomes’) of samples obtained from Indigenous children with otitis media.

The microbiome of otitis media with effusion

OBJECTIVES/HYPOTHESIS

The adenoid pad has been considered a reservoir for bacteria in the pathogenesis of otitis media with effusion. This study aimed to characterize the middle ear microbiota in children with otitis media with effusion and establish whether a correlation exists between the middle ear and adenoid microbiota.

STUDY DESIGN

Prospective, controlled study.

METHODS

Middle ear aspirates adenoid pad swabs were collected from 23 children undergoing ventilation tube insertion. Adenoid swabs from patients without ear disease were controls. Samples were analyzed using 16S rRNA sequencing on the Illumina MiSeq platform.

RESULTS

Thirty-five middle ear samples were collected. The middle ear effusion microbiota was dominated by Alloiococcus otitidis (23% mean relative abundance), Haemophilus (22%), Moraxella (5%), and Streptococcus (5%). Alloiococcus shared an inverse correlation with Haemophilus (P = .049) and was found in greater relative abundance in unilateral effusion (P = .004). The microbiota of bilateral effusions from the same patient were similar (P < .001). However, the otitis media with effusion microbiota were found to be dissimilar to that of the adenoid (P = .01), whereas the adenoid microbiota of otitis media with effusion and control patients were similar (P > .05) (permutational multivariate analysis of the variance).

CONCLUSIONS

Dissimilarities between the local microbiota of the adenoid and the middle ear question the theory that the adenoid pad is a significant reservoir to the middle ear in children with otitis media with effusion. A otitidis had the greatest cumulative relative abundance, particularly in unilateral effusions, and shares an inverse correlation with the relative abundance of Haemophilus.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:2844-2851, 2016.

Predominant Bacteria Detected from the Middle Ear Fluid of Children Experiencing Otitis Media: A Systematic Review

BACKGROUND

Otitis media (OM) is amongst the most common childhood diseases and is associated with multiple microbial pathogens within the middle ear. Global and temporal monitoring of predominant bacterial pathogens is important to inform new treatment strategies, vaccine development and to monitor the impact of vaccine implementation to improve progress toward global OM prevention.

METHODS

A systematic review of published reports of microbiology of acute otitis media (AOM) and otitis media with effusion (OME) from January, 1970 to August 2014, was performed using PubMed databases.

RESULTS

This review confirmed that Streptococcus pneumoniae and Haemophilus influenzae, remain the predominant bacterial pathogens, with S. pneumoniae the predominant bacterium in the majority reports from AOM patients. In contrast, H. influenzae was the predominant bacterium for patients experiencing chronic OME, recurrent AOM and AOM with treatment failure. This result was consistent, even where improved detection sensitivity from the use of polymerase chain reaction (PCR) rather than bacterial culture was conducted. On average, PCR analyses increased the frequency of detection of S. pneumoniae and H. influenzae 3.2 fold compared to culture, whilst Moraxella catarrhalis was 4.5 times more frequently identified by PCR. Molecular methods can also improve monitoring of regional changes in the serotypes and identification frequency of S. pneumoniae and H. influenzae over time or after vaccine implementation, such as after introduction of the 7-valent pneumococcal conjugate vaccine.

CONCLUSIONS

Globally, S. pneumoniae and H. influenzae remain the predominant otopathogens associated with OM as identified through bacterial culture; however, molecular methods continue to improve the frequency and accuracy of detection of individual serotypes. Ongoing monitoring with appropriate detection methods for OM pathogens can support development of improved vaccines to provide protection from the complex combination of otopathogens within the middle ear, ultimately aiming to reduce the risk of chronic and recurrent OM in vulnerable populations.

Genetic similarity between adenoid tissue and middle ear fluid isolates of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis from Iranian children with otitis media with effusion

BACKGROUND

Otitis media with effusion (OME) is a common disease among children, in the pathogenesis of which bacterial infections play a critical role. It was suggested that adenoid tissue could serve as a reservoir for bacterial infection, the eustachian tubes being the migration routes of bacteria into the middle ear cavity. The aim of this study was to investigate the genetic similarity between isolates of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, obtained from adenoid tissue and middle ear fluid.

METHODS

A total of 60 specimens of middle ear fluids (MEFs) and 45 specimens of adenoid tissue were obtained from 45 children with OME. All the samples were inoculated on culture media for bacterial isolation and identification. The genetic similarity between bacterial isolates was determined by pulsed-field gel electrophoresis (PFGE).

RESULTS

The same bacterial species were simultaneously isolated from adenoid tissue and MEFs of 14 patients, among which, 6 pairs of M. catarrhalis, 5 pairs of S. pneumoniae and 3 pairs of H. influenzae were identified.

CONCLUSIONS

Based on the genetic similarities between isolate pairs, found by PFGE analysis, this study suggested that M. catarrhalis, S. pneumoniae and H. influenzae colonize the adenoid tissue, then migrate to the middle ear cavity and, hence, contribute to the total pathogenesis of OME.

Induction of inflammatory responses from THP-1 cells by cell-free filtrates from clinical isolates of Alloiococcus otitidis

In our model system using the THP-1 monocytic cell line, whole heat-killed cells of Alloiococcus otitidis elicited several pro-inflammatory cytokines identified in ear effusions of children with otitis media (OM). Levels of these cytokines were equivalent to or greater than those elicited by a standard Gram-positive otopathogen, Streptococcus pneumoniae. The current study examined the hypothesis that extracellular material produced by A. otitidis might also contribute to the inflammatory responses in OM. Cell-free culture filtrates of recent A. otitidis isolates ( n = 39) were tested for induction of pro-inflammatory cytokines from THP-1 cells primed with IFN-γ. The highest responses were from IL-8 followed by IL-1β, and the lowest from IL-6. Filtrates from nine isolates were treated with lysozyme or proteinase K to assess the nature of the extracellular stimulants. Peptidoglycan was not a major component eliciting the responses. There was no correlation between colony type or β-haemolysin production. Proteinase K treatment indicated extracellular proteins might induce the inflammatory responses, particularly the 70–75 ku band. Further studies on the role of the extracellular proteins of A. otitidis and cytokine responses in pathogenesis of ear infections are needed.

Characterization of Alloiococcus otitidis strains isolated from children with otitis media with effusion by Pulsed-Field Gel Electrophoresis

OBJECTIVE

Alloiococcus otitidis is a slow growing organism which has been isolated in a few studies on patients with otitis media with effusion (OME). According to the literature review, there is no study about the molecular typing of A. otitidis. In this study, the characteristics of A. otitidis isolates from patients with OME were investigated via Pulsed-Field Gel Electrophoresis (PFGE) typing method.

METHODS

A total of 50 children with OME, who underwent myringotomy or who had an insertion of a ventilation tube, were included in this study. The isolates were identified to the species level as A. otitidis using standard biochemical methods, following which the amplification and sequencing of the 16S rRNA gene were carried out. The molecular characteristic of A. otitidis was investigated by PFGE technique.

RESULTS

Fifteen isolates of A. otitidis were identified in the middle ear fluid of the patients. All the isolates were susceptible to ampicillin, amoxicillin/clavulanate and fluoroquinolones. All of the 15 isolates were typed by PFGE method and were found to include 13 different PFGE types.

CONCLUSION

The current study, being the first reports on the molecular typing of A. otitidis by PFGE method, shows that A. otitidis is a heterogenic organism in Iranian children who have OME.

Quantitative PCR of ear discharge from Indigenous Australian children with acute otitis media with perforation supports a role for Alloiococcus otitidis as a secondary pathogen

Background

Otitis media is endemic in remote Indigenous communities of Australia’s Northern Territory. Alloiococcus otitidis is an outer ear commensal and putative middle ear pathogen that has not previously been described in acute otitis media (AOM) in this population. The aims of this study were to determine the presence, antibiotic susceptibility and bacterial load of A. otitidis in nasopharyngeal and ear discharge swabs collected from Indigenous Australian children with AOM with perforation.

Methods

Paired nasopharyngeal and ear discharge swabs from 27 children with AOM with perforation were tested by A. otitidis quantitative PCR (qPCR). Positive swabs were cultured for 21 days. Total and respiratory pathogen bacterial loads in A. otitidis-positive swabs were determined by qPCR.

Results

A. otitidis was detected by qPCR in 11 ear discharge swabs from 10 of 27 (37%) children, but was not detected in paired nasopharyngeal swabs. A. otitidis was cultured from 5 of 11 qPCR-positive swabs from four children. All A. otitidis isolates had minimum inhibitory concentrations consistent with macrolide resistance. All A. otitidis qPCR-positive swabs were culture-positive for other bacteria. A. otitidis bacterial load ranged from 2.2 × 10⁴-1.1 × 10⁸ cells/swab (median 1.8 × 10⁵ cells/swab). The relative abundance of A. otitidis ranged from 0.01% to 34% of the total bacterial load (median 0.7%). In 6 of 11 qPCR-positive swabs the A. otitidis relative abundance was <1% and in 5 of 11 it was between 2% and 34%. The A. otitidis bacterial load and relative abundance measures were comparable to that of Haemophilus influenzae.

Conclusions

A. otitidis can be a dominant species in the bacterial communities present in the ear discharge of Indigenous children with AOM with perforation. The absence of A. otitidis in nasopharyngeal swabs suggests the ear canal as the likely primary reservoir. The significance of A. otitidis at low relative abundance is unclear; however, at higher relative abundance it may be contributing to the associated inflammation. Further studies to better understand A. otitidis as a secondary otopathogen are warranted, particularly in populations at high-risk of progression to chronic suppurative otitis media and where macrolide therapies are being used.

Concurrent assay for four bacterial species including alloiococcus otitidis in middle ear, nasopharynx and tonsils of children with otitis media with effusion: a preliminary report

Objectives

To detect the prevalences of Alloiococcus otitidis, as well as Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis in children with chronic otitis media with effusion (OME) and to simultaneously investigate the colonization of these bacteria in the nasopharynx and palatine tonsils of these patients.

Methods

The study included 34 pediatric patients with OME, and 15 controls without OME. In the study group, A. otitidis, H. influenzae, S. pneumoniae, and M. catarrhalis were investigated in the samples obtained from middle ear effusions (MEE), nasopharyngeal swabs (NPS) and tonsillar swabs (TS), using multiplex polymerase chain reaction (PCR) and conventional culture methods. Only the samples obtained from NPS and TS were studied with the same techniques in the control group.

Results

A. otitidis was isolated only in MEE and only with multiplex PCR method. A. otitidis, S. pneumoniae, M. catarrhalis, H. influenzae were identified in 35%, 8.8%, 8.8%, and 2.9%, respectively, in 34 MEE. A. otitidis was not isolated in NPS or TS of the study and the control groups.

Conclusion

The prevalence of A.otitidis is high in children with OME and A.otitidis doesn't colonize in the nasopharynx or tonsil.

Bacterial pathogens related to chronic suppurative otitis media in individuals with cleft palate: bacteriological culture and polymerase chain reaction

OBJECTIVE

To characterize the microbial etiology of chronic suppurative otitis media comparing the methods of classical bacteriological culture and polymerase chain reaction.

DESIGN/SETTING/PATIENTS

Bacteriological analysis by classical culture and by molecular polymerase chain reaction of 35 effusion otitis samples from patients with cleft lip and palate attending the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo, Bauru, Brazil.

INTERVENTIONS

Collection of clinical samples of otitis by effusion through the external auditory tube.

MAIN OUTCOME MEASURE

Otolaryngologic diagnosis of chronic suppurative otitis media.

RESULTS

Positive cultures were obtained from 83% of patients. Among the 31 bacterial lineages the following were isolated. In order of decreasing frequency: Pseudomonas aeruginosa (54.9%), Staphylococcus aureus (25.9%), and Enterococcus faecalis (19.2%). No anaerobes were isolated by culture. The polymerase chain reaction was positive for one or more bacteria investigated in 97.1% of samples. Anaerobe lineages were detected by the polymerase chain reaction method, such as Fusobacterium nucleatum , Bacteroides fragilis , and Peptostreptococcus anaerobius .

CONCLUSIONS

Patients with cleft lip and palate with chronic suppurative otitis media presented high frequency of bacterial infection in the middle ear. The classical bacteriological culture did not detect strict anaerobes, whose presence was identified by the polymerase chain reaction method.

Simultaneous assay for four bacterial species including Alloiococcus otitidis using multiplex-PCR in children with culture negative acute otitis media

BACKGROUND

The 3 most commonly encountered bacteria in acute otitis media (AOM) are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Conventional culture methods detect these pathogens in only 60% to 70% of cases of AOM. Alloiococcus otitidis, another potential pathogen, has often been ignored.

METHODS

Tympanocentesis was performed in 97 children with AOM presenting with a bulging tympanic membrane (TM) producing 170 middle ear fluids (MEFs). S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis were isolated in 21%, 32%, 8%, and 0% of MEFs, respectively; no otopathogen was isolated in 29% of MEFs. In nasopharyngeal cultures at the time of AOM diagnosis, 34%, 36%, 17%, and 0% and in oropharyngeal cultures, 7%, 31%, 11%, and 0% grew S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis, respectively. No otopathogen was isolated in 23% of nasopharyngeal and 20% of oropharyngeal cultures. Multiplex polymerase chain reaction (PCR) was used to detect DNA of the 4 bacterial species in culture negative samples.

RESULTS

All culture-positive MEF, nasopharyngeal and oropharyngeal samples tested were also multiplex-PCR positive, indicating the reliability of the method. Culture-negative samples of MEF from children with a bulging TM yielded S. pneumoniae, H. influenzae, M. catarrhalis, and A. otitidis DNA in 51%, 35%, 14%, and 32% of MEF, in 45%, 31%, 10%, and 9% of nasopharyngeal and in 31%, 23%, 0%, and 3% of oropharyngeal, respectively. In 9% of the cases A. otitidis DNA was found without detection of a second organism in MEF.

CONCLUSIONS

Conventional culture detected otopathogens in MEF of children with a bulging TM in 71%; using multiplex-PCR, otopathogens were detected in 88% of MEF (P < 0.01). Similar improved detection of otopathogens was noted with nasopharyngeal and oropharyngeal cultures.

New horizons: otitis media research in Australia

Otitis media affects nearly all children worldwide. Despite an enormous amount of research, our understanding of this common condition continues to be challenged. New pathogens involved in otitis media are still being identified. The importance of interactions between viral and bacterial infection and the role of new vaccines need to be clarified. The proposal that bacteria can become more resistant to therapy through biofilm formation and intracellular infection could have important implications for treatment. The most important clinical research findings have been summarised in systematic reviews. In developed countries, research supporting "watchful waiting" of otitis media with effusion and acute otitis media have had most impact on evidence-based clinical practice guidelines. Indigenous Australian children remain at risk of more severe otitis media. Research programs targeting this population have been well supported. Unfortunately, interventions that can dramatically improve outcomes have remained elusive. For children at high risk of otitis media, health care services should concentrate on accurate diagnosis, antibiotic treatment of suppurative infections, and scheduled follow-up of affected children. Despite the lack of recent studies, strategies to minimise the impact the hearing loss associated with otitis media are important. Improvements in education, hygiene practices, and living conditions are likely to reduce the incidence and severity of otitis media. Studies of these types of interventions are needed.

The prevalence of middle ear pathogens in the outer ear canal and the nasopharyngeal cavity of healthy young adults

Culturing middle ear fluid samples from children with chronic otitis media with effusion (OME) using standard techniques results in the isolation of bacterial species in approximately 30-50% of the cases. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, the classic middle ear pathogens of acute otitis media, are involved but, recently, several studies suggested Alloiococcus otitidis as an additional pathogen. In the present study, we used species-specific PCRs to establish the prevalence, in both the nasopharyngeal cavity and the outer ear, of H. influenzae, M. catarrhalis, S. pneumoniae and A. otitidis. The study group consisted of 70 healthy volunteers (aged 19-22 years). The results indicate a high prevalence (>80%) of A. otitidis in the outer ear in contrast to its absence in the nasopharynx. H. influenzae was found in both the outer ear and the nasopharynx (6% and 14%, respectively), whereas S. pneumoniae and M. catarrhalis were found only in the nasopharynx (9% and 34%, respectively).A. otitidis, described as a fastidious organism, were able to be cultured using an optimized culture protocol, with prolonged incubation, which allowed the isolation of A. otitidis in five of the nine PCR-positive samples out of the total of ten samples tested. Given the absence of the outer ear inhabitant A. otitidis from the nasopharynx, its role in the aetiology of OME remains ambiguous because middle ear infecting organisms are considered to invade the middle ear from the nasopharynx through the Eustachian tube.

Lack of Chlamydophila pneumoniae and predominance of Alloiococcus otitidis in middle ear fluids of children with otitis media with effusion

OBJECTIVE

To investigate the presence of Chlamydophila pneumoniae and other bacterial pathogens in middle ear effusion samples obtained from children with otitis media with effusion (OME).

MATERIALS AND METHODS

Twenty-eight children (mean age 7.03; standard deviation 2.18) with OME unresponsive to medical therapy were included in the study. All of the children underwent ventilation tube insertion under general anesthesia. Eighteen patients were bilaterally affected whereas 10 children had unilateral disease. The middle ear fluids (46 samples in total) were collected during ventilation tube insertion, and were evaluated subsequently for the presence of C. pneumoniae and other bacterial pathogens using polymerase chain reaction (PCR).

RESULTS

Although all samples were negative for C. pneumoniae, bacterial DNA was detected in 21 of 46 samples. Overall 40% of the patients (4/10) with unilateral involvement, and 61% of the patients (11/18) with bilateral involvement were positive for bacterial DNA. In 6 patients with bilateral OME bilateral samples were positive, whereas 5 patients with bilateral OME showed only unilateral positivity. According to the results of DNA sequencing analysis, all of the positive samples harbored only one bacterial species. In 12 of 46 samples Alloiococcus otitidis DNA (26%), in 7 Haemophilus influenzae DNA (15%), in one Streptococcus pneumoniae DNA (2%) and in one Moraxella catarrhalis DNA (2%) were present.

CONCLUSIONS

Our findings support that C. pneumoniae does not seem to have a role in OME in children whereas A. otitidis was found to be more frequent than the other common pathogens. Further studies are required to elucidate the exact pathogenetic role of these microorganisms in OME.

Alloiococcus otitidis--otitis media pathogen or normal bacterial flora?

During the last decade a new potential otitis media pathogen, Alloiococcus otitidis, has been studied. It is still not clear whether this bacterium really is a pathogen, although it has been found in a high percentage of middle ear effusions in children. The present study aimed to investigate the presence of A. otitidis in the nasopharynx and outer ear canals, and to develop a culture method that would make it possible to isolate A. otitidis from these locations. Nasopharyngeal samples (n = 129) from children below 6 years were investigated by conventional culture on blood agar plates with 6% saline and rabbit antisera against A. otitidis, and by a PCR method. In the same way, we investigated 10 samples from vestibulum nasi of healthy persons, 68 samples from outer ear canals of patients with acute or chronic ear problems, and 24 samples from outer ear canals of healthy persons. In a rat model of acute otitis media, we instilled living A. otitidis into rat middle ears through the tympanic bulla and evaluated the outcome clinically by otomicroscopy at days 3, 6 and 14. Of the 129 nasopharyngeal cultures, 9 were positive for A. otitidis by PCR, but none by the culture method. Of the 68 samples from patients with running ears, 4 were positive for A. otitidis by PCR, but none by the culture method. Of the 24 healthy ear canals, 7 were positive for A. otitidis by PCR and 3 of them also by the culture method. No A. otitidis could be found from the vestibulum nasi. The rat experiment showed that the reactions in the middle ears were mild; we could not provoke a purulent acute otitis media in any of the rats. There was a 7% prevalence of A. otitidis in children below 6 years. The highest prevalence (29%) was found in outer ear canals of healthy persons, which strongly suggests that A. otitidis is part of the normal bacterial flora of the outer ear canal. The doubtful pathogenicity is also confirmed by the fact that--in the rat model--A. otitidis elicited only a mild response in the middle ear. It was possible to isolate A. otitidis using a blood agar plate with 6% saline.

Serous otitis media in children: implication of Alloiococcus otitidis

OBJECTIVE

Otitis media with effusion (OME) has long been considered to be a noninfective disease resulting from a eustachian tube dysfunction. However, several microbiological techniques have shown bacteria in the middle ear fluids from patients with OME. Alloiococcus otitidis has been detected in the middle ear fluid from patients with OME. The exact role of this infectious agent in the pathogenesis of OME has yet to be elucidated.

STUDY DESIGN

A prospective clinical trial.

SETTING

A tertiary university-based referral center.

PATIENTS

The inclusion criteria included 110 patients aged between 1 and 12 years. The control group included samples obtained from 30 healthy children undergoing a cochlear implantation. The second group included 40 middle ear effusions (MEEs) that were collected from 40 pediatric OME patients during the placement of the ventilation tube. As for the third group, they were 40 children with acute otitis media.

INTERVENTION

The bacterial analysis of the MEE was performed by means of microbiological culture-specific techniques.

MAIN OUTCOME MEASURE

Positive cultures for A. otitidis as analyzed by bacteriological analysis of samples from the middle ear mucosa and MEE.

RESULTS

Bacteria were present in the culture of 72.5% (29) of the patients with OME. Alloiococcus otitidis was the most frequent bacterium in OME (48.27%) as well as Haemophilus influenzae nonserotype B (17.24%). Streptococcus pneumoniae was the most commonly detected pathogen in acute otitis media (37.5%), and then H. influenzae nonserotype B (25%). For most of the OME cases, only A. otitidis bacteria were isolated.

CONCLUSION

We observed a high rate of culture positivity for A. otitidis in patients with clinical OME without suppuration. Further studies are needed to confirm whether the association of A. otitidis with OME represents causality. Antibiotic therapy aimed at A. otitidis is complicated by reported resistance, thus emphasizing the importance of our understanding of the pathogenetic role played by this organism

Interleukin-8 induction via NF-kappaB, p38 mitogen-activated protein kinase and extracellular signal-regulated kinase 1/2 pathways in human peripheral blood mononuclear cells by Alloiococcus otitidis

Alloiococcus otitidis is a newly recognized species of gram-positive bacteria frequently associated with otitis media. Although immunostimulating activity of this organism has been investigated, little is known about the signaling pathways of chemokine/cytokine induction by this organism. We investigated the role of NF-kappaB and mitogen-activated protein (MAP) kinases in chemokine interleukin-8 (IL-8) production by human peripheral blood mononuclear cells (PBMCs) after stimulation with A. otitidis. The organism could induce in vitro IL-8 production in human PBMCs. I kappa B alpha, NF-kappaB, p38 MAP kinase, p44/42 MAP kinase (ERK1/2) became phosphorylated in PBMCs after stimulation with A. otitidis. And, inhibitors of NF-kappaB (caffeic acid phenylethyl ester), p38 (SB 203580), or ERK1/2 (PD 98059) significantly reduced IL-8 induction by the organism. These results were similar to findings in IL-8 induction by Streptococcus pneumoniae, another gram-positive major middle ear pathogen. Our preliminary study suggests that multiple pathways including NF-kappaB, p38, and ERK1/2 were simultaneously activated, and were associated with IL-8 induction by A. otitidis in human PBMCs.

Isolation of Alloiococcus otitidis from Indigenous and non-Indigenous Australian children with chronic otitis media with effusion

During the last decade Alloiococcus otitidis has been identified in specimens from patients with chronic otitis media with effusion. Whereas most of those studies employed molecular techniques, we used minor modifications of conventional microbiological methods to isolate and identify A. otitidis in samples obtained from 20/50 (40%) children referred for myringotomy. Alloiococcus otitidis was isolated from 10/22 (45%) Indigenous and 10/28 (36%) non-Indigenous children. This is the first report of isolation of A. otitidis from Australian children with chronic otitis media. All isolates were sensitive to penicillin, but 14/20 (70%) of the isolates were resistant or partially resistant to erythromycin as assessed by the E-test.

Evidence of local antibody response against Alloiococcus otitidis in the middle ear cavity of children with otitis media

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.

High incidence of Alloiococcus otitidis in children with otitis media, despite treatment with antibiotics

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.

High frequency of Alloiococcus otitidis in the nasopharynx and in the middle ear cavity of otitis-prone children

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.

Recent Developments in the Treatment of Otitis Media with Effusion

The management of otitis media with effusion (OME) has received much attention recently as a result of, among other factors, the development of resistant bacteria and the finding of less long-term impact of middle-ear effusion (MEE) on development than previously believed. Guidelines have recently been published for the management of OME promoting more accurate diagnosis, particularly distinguishing acute otitis media from OME, and recommending the 'judicious' use of antibacterials. Today, more emphasis is being placed on prevention of disease by reducing risk factors and the development of vaccines. The identification of susceptibility genes may lead to better understanding of the pathogenesis of otitis media, which in turn may lead to the development of more innovative and satisfactory methods for prevention and treatment.

Prevalência elevada do Alloiococcus otitidis na otite média com efusão através da PCR simultânea

A etiologia da otite média com efusão (OME) não é completamente conhecida, mas agentes infecciosos podem contribuir para sua patogênese. O conhecimento sobre a epidemiologia bacteriana da OME em áreas geográficas distintas é essencial para a implementação de tratamentos racionais, quando indicados. OBJETIVO: Determinar a prevalência do Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis e Alloiococcus otitidis nas efusões da orelha média de crianças com otite média recorrente (OMR) e otite média com efusão crônica (OMEC) que foram submetidas à miringotomia e comparar os resultados obtidos por cultura e PCR. FORMA DE ESTUDO: Estudo clínico com coorte transversal. MATERIAL E MÉTODO: 128 efusões obtidas por timpanocentese de 75 crianças entre 11 meses e 10 anos de idade foram analisadas por cultura e PCR simultânea. RESULTADOS: Cultivaram-se bactérias em 25,1% das amostras e os patógenos principais foram encontrados em 19,6%. O A.otitidis não foi isolado em cultura. A PCR identificou bactérias em 85,9%, com os seguintes resultados individuais: A.otitidis, 52,3%; H.influenzae, 39,1%; S.pneumoniae, 12,5% e M.catarrhalis, 10,2%. A PCR foi significativamente mais sensível que a cultura (P<0,01). O S.pneumoniae foi mais encontrado em OMR do que em OMEC (P=0,038). CONCLUSÕES: A prevalência das bactérias na OME em um grupo de crianças brasileiras é semelhante àquelas relatadas em outros países, sendo o H.influenzae o mais encontrado dentre os patógenos principais da orelha média. O S.pneumoniae foi mais freqüente em OMR do que em OMEC. A PCR é mais sensível na detecção de bactérias na efusão da orelha média, comparada com cultura, e é essencial para a identificação do A.otitidis. O elevado percentual de detecção do A.otitidis sugere mais investigações sobre sua atuação no início e no prolongamento de doenças da orelha média.

Alloiococcus otitidis in acute otitis media

OBJECTIVE

The bacterium Alloiococcus otitidis has been found to be associated with otitis media with effusion (OME). When the culture method is used, its detection rate is low, whereas applying the polymerase chain reaction (PCR) yields significantly higher frequencies. This study was carried out to investigate the incidence of A. otitidis in children with acute otitis media (AOM).

METHODS

Multiplex PCR was used to detect A. otitidis together with Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae in the middle ear effusions (MEEs) of 118 children with AOM. The clinical outcome of AOM and the bacterial findings of MEEs were compared.

RESULTS

A. otitidis was detected in 25% (30 of 118) of the tested MEE samples. Children over 2 years of age had significantly more often A. otitidis-positive MEEs (37%; 22 of 59) than younger children (14%; 8 of 59) (chi-square test, P<0.01). There were no significant differences in the duration, clinical failures (after antibiotic treatment), or number of recurrences of AOM between the A. otitidis-positive and A. otitidis-negative children.

CONCLUSIONS

A. otitidis is found from the MEEs of AOM. The present data suggest that it has no clinical significance in AOM, and it does not increase the risk of developing OME after AOM.

The Etiology, Pathophysiology, and Management of Otitis Media with Effusion

Otitis media with effusion (OME) is a common and important condition that may result in developmental delay in children, and significant health care resources are devoted to its management. Newer techniques including polymerase chain reaction are implicating organisms not previously considered important in etiology. The role of gastroesophageal reflux as a cause of OME is likely to receive greater research attention. Regarding prevention, more is being learned about potentially modifiable risk factors such as environmental smoke, care outside the home, and breast feeding. Although immunization may to play a role in the future, existing evidence suggests that the general population of children should not be immunized in order to prevent OME. Several major studies have recently added to the understanding of epidemiology and management. Large trials in the United States, the Netherlands, and the UK suggest that OME is not an appropriate condition to include in a screening program. In addition, the advantages of early treatment with ventilation tubes over watchful waiting in terms of language development tend be modest and diminish by about 18 months. Treatment with hearing aids should be further evaluated. The search for effective medical management continues, and better ways are being identified of targeting interventions to those children with OME who are most likely to benefit.