Lack of Chlamydophila pneumoniae and predominance of Alloiococcus otitidis in middle ear fluids of children with 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.

Altered Middle Ear Microbiome in Children With Chronic Otitis Media With Effusion and Respiratory Illnesses

Chronic otitis media with effusion (COME) is a common childhood disease characterized by an accumulation of fluid behind the eardrum. COME often requires surgical intervention and can also lead to significant hearing loss and subsequent learning disabilities. Recent characterization of the middle ear fluid (MEF) microbiome in pediatric patients has led to an improved understanding of the microbiota present in the middle ear during COME. However, it is not currently known how the MEF microbiome might vary due to other conditions, particularly respiratory disorders. Here, we apply an amplicon sequence variant (ASV) pipeline to MEF 16S rRNA high-throughput sequencing data from 50 children with COME (ages 3–176 months) undergoing tube placement. We achieve a more detailed taxonomic resolution than previously reported, including species and genus level resolution. Additionally, we provide the first report of the functional roles of the MEF microbiome and demonstrate that despite high taxonomic diversity, the functional capacity of the MEF microbiome remains uniform between patients. Furthermore, we analyze microbiome differences between children with COME with and without a history of lower airway disease (i.e., asthma or bronchiolitis). The MEF microbiome was less diverse in participants with lower airway disease than in patients without, and phylogenetic β-diversity (weighted UniFrac) was significantly different based on lower airway disease status. Differential abundance between patients with lower airway disease and those without was observed for the genera Haemophilus, Moraxella, Staphylococcus, Alloiococcus, and Turicella. These findings support previous suggestions of a link between COME and respiratory illnesses and emphasize the need for future study of the middle ear and respiratory tract microbiomes in diseases such as asthma and bronchiolitis.

Alloiococcus otitidis Forms Multispecies Biofilm with Haemophilus influenzae: Effects on Antibiotic Susceptibility and Growth in Adverse Conditions

Otitis media with effusion (OME) is a biofilm driven disease and commonly accepted otopathogens, such as Haemophilus influenzae, Streptococcus pneumonia, and Moraxella catarrhalis, have been demonstrated to form polymicrobial biofilms within the middle ear cleft. However, Alloiococcus otitidis (A. otitidis), which is one of the most commonly found bacteria within middle ear aspirates of children with OME, has not been described to form biofilms. The aim of this study was to investigate whether A. otitidis can form biofilms and investigate the impact on antibiotic susceptibility and survivability in polymicrobial biofilms with H. influenzae in vitro. The ability of A. otitidis to form single-species and polymicrobial biofilms with H. influenzae was explored. Clinical and commercial strains of A. otitidis and H. influenzae were incubated in brain heart infusion with and without supplementation. Biofilm was imaged using confocal laser scanning microscopy and scanning electron microscopy. Quantification of biofilm biomass and viable bacterial number was assessed using crystal violet assays and viable cell counting in both optimal growth conditions and in adverse growth conditions (depleted media and sub-optimal growth temperature). Antimicrobial susceptibility and changes in antibiotic resistance of single-species and multi-species co-culture were assessed using a microdilution method to assess minimal bactericidal concentration and E-test for amoxicillin and ciprofloxacin. A. otitidis formed single-species and polymicrobial biofilms with H. influenzae. Additionally, whilst strain dependent, combinations of polymicrobial biofilms decreased antimicrobial susceptibility, albeit a small magnitude, in both planktonic and polymicrobial biofilms. Moreover, A. otitidis promoted H. influenzae survival by increasing biofilm production in depleted media and at suboptimal growth temperature. Our findings suggest that A. otitidis may play an indirect pathogenic role in otitis media by altering H. influenzae antibiotic susceptibility and enhancing growth under adverse conditions.

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.

Role of bacterial biofilm in development of middle ear effusion

Biofilms have been implicated in the development of several chronic upper respiratory tract infections. Role of bacterial biofilms has been well studied in the pathogenesis of chronic rhinosinusitis. However, its impact on development of middle ear effusion is still a matter of debate. To study the extent of surface adenoid biofilm and evaluate its role in the pathogenesis of chronic otitis media with effusion in children. The study was carried out on 40 children in Alexandria Main University Hospital between 1 and 16 years of age without sex predilection, who were divided into two groups. The first group (20 children) had otitis media with effusion associated with adenoid hypertrophy, whereas the second group (20 children) had adenoid hypertrophy without middle ear effusion. Adenoidectomy with ventilation tube insertion was done for group 1 cases, whereas, only Adenoidectomy was done for group 2 cases. The samples were processed for the detection of biofilms by scanning electron microscopy. The biofilm formation was graded according to extension. Biofilm formation was detected on all samples for group 1. Adenoids removed from patients with otitis media with effusion had higher-grade biofilm formation than the other group (P 0.0001). No correlation was found between adenoid size and biofilm formation. In pediatric population, adenoid surface biofilm formation may be involved in the pathogenesis otitis media with effusion.

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.

Identification of Alloiococcus otitidis, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae in Children With Otitis Media With Effusion

Background:

Based on many studies, otitis media with effusion (OME) is one of the major causes of childhood hearing loss, social malformation and medical costs. The pathogenesis still remains unclear, though it is known that this complication is closely related to bacterial infections. Alloiococcus otitidis, Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis are the most common bacterial pathogens isolated from middle ear effusions (MEEs).

Objectives:

Due to the prevalence of OME in children, we decided to investigate bacterial agents that cause diseases such as A. otitidis, H. influenzae, S. pneumonia and M. catarrhalis in these subjects.

Patients and Methods:

Forty-five children between one and 15 years of age were selected for this study. Seventy specimens were collected from MEE by myringotomy and inoculated in PBS buffer. Conventional culture and PCR methods were used for identification of bacterial agents.

Results:

The bacterial cultures in 8.6% of samples were positive by conventional culture, with A. otitidis, M. catarrhalis and S. pneumoniae present in 1.4%, 2.9% and 4.3% of samples, respectively. No H. influenzae was isolated. By the PCR method, A. otitidis was the most frequently isolated bacterium, found in 25.7% of samples, followed by S. pneumoniae, M. catarrhalis and H. influenzae, which were identified in 20%, 12% and 20% of samples, respectively. Overall, 55 out of 70 samples were positive by both the PCR and culture method.

Conclusions:

It can be concluded that A. otitidis was the major causative agent of MEE in children with OME. Therefore clinicians should be aware that bacterial infection plays an important role in the progression of acute otitis media to OME in children of our region.

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.

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.