Bacterial involvement in otitis media with effusion

The Prevalence and Association of Biofilms With Otitis Media With Effusion: A Systematic Review and Meta-Analysis

PURPOSE

We aimed to identify the role of bacterial biofilms in the chronicity of otitis media with effusion and its resistance to antibiotics. We illustrated this role by reviewing, analyzing, and correlating the findings with the results of the included studies to reach clear evidence.

METHODS

A comprehensive search of electronic databases (Scopus, PubMed, Web of Science, Cochrane, and GHL databases) was performed for all studies using the following strategy till April 2021 with the search terms: Biofilm and Middle ear effusion. We found 935 references, 421 were duplicates, and 514 were needed for further screening, and it was as follows: PubMed 215, Scopus 18, Cochrane 130, Web of Science 136, and GHL 15.

RESULTS

The pooled prevalence of culture-positive effusions was estimated to be 40% (95% CI [28%, 53%]) of the total OME population. Overall, the prevalence of PCR-positive effusions was estimated to be 97% (95% CI [95%, 99%]) of the total OME population. The pooled prevalence of EM-positive effusions was estimated to be 82% (95% CI [69%, 95%]) of the total OME population.

CONCLUSION

The data presented in this study coincide with the significant role of bacterial biofilms in the pathogenesis of chronic otitis media with effusion. The involvement of bacterial biofilm as a component of the OME pathogenic process can help us to explain why antimicrobial therapy is not always effective in the eradication of the disease process and, also explain the recurrence of middle ear effusion after treatment with tympanostomy tubes either with or without adenoidectomy.

Otitis media: recent advances in otitis media vaccine development and model systems

Otitis media is an inflammatory disorder of the middle ear caused by airways-associated bacterial or viral infections. It is one of the most common childhood infections as globally more than 80% of children are diagnosed with acute otitis media by 3 years of age and it is a common reason for doctor's visits, antibiotics prescriptions, and surgery among children. Otitis media is a multifactorial disease with various genetic, immunologic, infectious, and environmental factors predisposing children to develop ear infections. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are the most common culprits responsible for acute otitis media. Despite the massive global disease burden, the pathogenesis of otitis media is still unclear and requires extensive future research. Antibiotics are the preferred treatment to cure middle ear infections, however, the antimicrobial resistance rate of common middle ear pathogens has increased considerably over the years. At present, pneumococcal and influenza vaccines are administered as a preventive measure against otitis media, nevertheless, these vaccines are only beneficial in preventing carriage and/or disease caused by vaccine serotypes. Otitis media caused by non-vaccine serotype pneumococci, non-typeable H. influenza, and M. catarrhalis remain an important healthcare burden. The development of multi-species vaccines is an arduous process but is required to reduce the global burden of this disease. Many novel vaccines against S. pneumoniae, non-typeable H. influenza, and M. catarrhalis are in preclinical trials. It is anticipated that these vaccines will lower the disease burden and provide better protection against otitis media. To study disease pathology the rat, mouse, and chinchilla are commonly used to induce experimental acute otitis media to test new therapeutics, including antibiotics and vaccines. Each of these models has its advantages and disadvantages, yet there is still a need to develop an improved animal model providing a better correlated mechanistic understanding of human middle ear infections, thereby underpinning the development of more effective otitis media therapeutics. This review provides an updated summary of current vaccines against otitis media, various animal models of otitis media, their limitations, and some future insights in this field providing a springboard in the development of new animal models and novel vaccines for otitis media.

Antibiotics for otitis media with effusion (OME) in children

BACKGROUND

Otitis media with effusion (OME) is an accumulation of fluid in the middle ear cavity, common amongst young children. The fluid may cause hearing loss. When persistent, it may lead to developmental delay, social difficulty and poor quality of life. Management of OME includes watchful waiting, autoinflation, medical and surgical treatment. Antibiotics are sometimes used to treat any bacteria present in the effusion, or associated biofilms.

OBJECTIVES

To assess the effects (benefits and harms) of oral antibiotics for otitis media with effusion (OME) in children.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register, CENTRAL, Ovid MEDLINE, Ovid Embase, Web of Science, ClinicalTrials.gov, ICTRP and additional sources for published and unpublished studies to 20 January 2023.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised trials in children aged 6 months to 12 years with unilateral or bilateral OME. We included studies that compared oral antibiotics with either placebo or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were determined following a multi-stakeholder prioritisation exercise and were: 1) hearing, 2) otitis media-specific quality of life and 3) anaphylaxis. Secondary outcomes were: 1) persistence of OME, 2) adverse effects, 3) receptive language skills, 4) speech development, 5) cognitive development, 6) psychosocial skills, 7) listening skills, 8) generic health-related quality of life, 9) parental stress, 10) vestibular function and 11) episodes of acute otitis media. We used GRADE to assess the certainty of evidence for each outcome. Although we included all measures of hearing assessment, the proportion of children who returned to normal hearing was our preferred method to assess hearing, due to challenges in interpreting the results of mean hearing thresholds.

MAIN RESULTS

We identified 19 completed studies that met our inclusion criteria (2581 participants). They assessed a variety of oral antibiotics (including penicillins, cephalosporins, macrolides and trimethoprim), with most studies using a 10- to 14-day treatment course. We had some concerns about the risk of bias in all studies included in this review. Here we report our primary outcomes and main secondary outcome, at the longest reported follow-up time. Antibiotics versus placebo We included 11 studies for this comparison, but none reported all of our outcomes of interest and limited meta-analysis was possible. Hearing One study found that more children may return to normal hearing by two months (resolution of the air-bone gap) after receiving antibiotics as compared with placebo, but the evidence is very uncertain (Peto odds ratio (OR) 9.59, 95% confidence interval (CI) 3.51 to 26.18; 20/49 children who received antibiotics returned to normal hearing versus 0/37 who received placebo; 1 study, 86 participants; very low-certainty evidence). Disease-specific quality of life No studies assessed this outcome. Presence/persistence of OME At 6 to 12 months of follow-up, the use of antibiotics compared with placebo may slightly reduce the number of children with persistent OME, but the confidence intervals were wide, and the evidence is very uncertain (risk ratio (RR) 0.89, 95% CI 0.68 to 1.17; 48% versus 54%; number needed to treat (NNT) 17; 2 studies, 324 participants; very low-certainty evidence). Adverse event: anaphylaxis No studies provided specific data on anaphylaxis. Three of the included studies (448 children) did report adverse events in sufficient detail to assume that no anaphylactic reactions occurred, but the evidence is very uncertain (very low-certainty evidence). Antibiotics versus no treatment We included eight studies for this comparison, but very limited meta-analysis was possible. Hearing One study found that the use of antibiotics compared to no treatment may result in little to no difference in final hearing threshold at three months (mean difference (MD) -5.38 dB HL, 95% CI -9.12 to -1.64; 1 study, 73 participants; low-certainty evidence). The only data identified on the return to normal hearing were reported at 10 days of follow-up, which we considered to be too short to accurately reflect the efficacy of antibiotics. Disease-specific quality of life No studies assessed this outcome. Presence/persistence of OME Antibiotics may reduce the proportion of children who have persistent OME at up to three months of follow-up, when compared with no treatment (RR 0.64, 95% CI 0.50 to 0.80; 6 studies, 542 participants; low-certainty evidence). Adverse event: anaphylaxis No studies provided specific data on anaphylaxis. Two of the included studies (180 children) did report adverse events in sufficient detail to assume that no anaphylactic reactions occurred, but the evidence is very uncertain (very low-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence for the use of antibiotics for OME is of low to very low certainty. Although the use of antibiotics compared to no treatment may have a slight beneficial effect on the resolution of OME at up to three months, the overall impact on hearing is very uncertain. The long-term effects of antibiotics are unclear and few of the studies included in this review reported on potential harms. These important endpoints should be considered when weighing up the potential short- and long-term benefits and harms of antibiotic treatment in a condition with a high spontaneous resolution rate.

Viral infection in chronic otitis media with effusion in children

Background

The role of respiratory viruses in chronic otitis media with effusion (COME) in children is not clearly defined. In our study we aimed to investigate the detection of respiratory viruses in middle ear effusions (MEE) as well as the association with local bacteria, respiratory viruses in the nasopharynx and cellular immune response of children with COME.

Methods

This 2017-2019 cross-sectional study included 69 children aged 2-6 undergoing myringotomy for COME. MEE and nasopharyngeal swabs were analyzed via PCR and CT-values for the genome and loads of typical respiratory viruses. Immune cell populations and exhaustion markers in MEE related to respiratory virus detection were studied via FACS. Clinical data including the BMI was correlated.

Results

Respiratory viruses were detected in MEE of 44 children (64%). Rhinovirus (43%), Parainfluenzavirus (26%) and Bocavirus (10%) were detected most frequently. Average Ct values were 33.6 and 33.5 in MEE and nasopharynx, respectively. Higher detection rates correlated with elevated BMI. Monocytes were elevated in MEE (9.5 ± 7.3%/blood leucocytes). Exhaustion markers were elevated on CD4+ and CD8+ T cells and monocytes in MEE.

Conclusion

Respiratory viruses are associated with pediatric COME. Elevated BMI was associated with increased rates of virus associated COME. Changes in cell proportions of innate immunity and expression of exhaustion markers may be related to chronic viral infection.

Biofilm-Forming Bacteria Implicated in Complex Otitis Media in Children in the Post-Heptavalent Pneumococcal Conjugate Vaccine (PCV7) Era

Background: Chronic media with effusion (COME) and recurrent acute otitis media (RAOM) are closely related clinical entities that affect childhood. The aims of the study were to investigate the microbiological profile of otitis-prone children in the post-PCV7 era and, to examine the biofilm-forming ability in association with clinical history and outcome during a two-year post-operative follow-up. Methods: In this prospective study, pathogens from patients with COME and RAOM were isolated and studied in vitro for their biofilm-forming ability. The minimum inhibitory concentrations (MIC) of both the planktonic and the sessile forms were compared. The outcome of the therapeutic method used in each case and patient history were correlated with the pathogens and their ability to form biofilms. Results: Haemophilus influenzae was the leading pathogen (35% in COME and 40% in RAOM), and Streptococcus pneumoniae ranked second (12% in COME and 24% in RAOM). Polymicrobial infections were identified in 5% of COME and 19% of RAOM cases. Of the isolated otopathogens, 94% were positive for biofilm formation. Conclusions: This is the first Greek research studying biofilm formation in complex otitis media-prone children population in the post-PCV7 era. High rates of polymicrobial infections, along with treatment failure in biofilms, may explain the lack of antimicrobial efficacy in otitis-prone children.

IL-17 is a Potential Therapeutic Target in a Rodent Model of Otitis Media with Effusion

Background

Otitis media with effusion (OME) is a non-suppurative inflammation of the middle ear that is characterized by middle ear effusion and hearing loss. However, the mechanisms of OME are not fully understood. The aim of this study was to determine the function and the mechanism of the IL-17 cytokine in the pathogenesis of OME and to investigate IL-17 as a potential strategy for the treatment of OME.

Methods

In this study, the OME rat model was induced by ovalbumin (OVA) as previously described. The severity of OME was determined with an oto-endoscope, by histochemical analysis, and by acoustic immittance. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of RNA-sequencing (RNA-seq) data was carried out to analyze the signaling pathways related to the pathogenesis of OME, which indicated that IL-17 is involved in OME. The anti-IL-17A monoclonal antibody was administrated by nasal drip to block IL-17 to treat OME in the rat model. The rats were finally injected intraperitoneally with the inhibitor of Notch signaling pathway to study the mechanisms of IL-17-induced inflammation. Serum and lavage fluid were collected for the detection of related cytokines, and middle ear tissue was collected for Western blot, quantitative real-time PCR (qRT-PCR), and immunohistochemical and immunofluorescence analysis.

Results

KEGG analysis of RNA-seq data suggested that the IL-17 signaling pathway might be involved in the onset of OME. IL-17 expression was confirmed to be increased in both the serum and the middle ear of the rat model. The monoclonal antibody against IL-17 neutralized IL-17, inhibited the inflammation in the middle ear, and reduced the overall severity of OME in vivo. Furthermore, the Notch signaling pathway was activated upon IL-17 upregulation in OME and was suppressed by IL-17 blockage. However, there was no change in IL-17 expression after Notch inhibitor treatment, which reduced the severity of OME in the rat middle ear.

Conclusion

IL-17 plays a key role in the pathogenesis of the OVA-induced OME rat model. IL-17 induced inflammatory responses via the Notch signaling pathway and targeting IL-17 might be an effective approach for OME therapy.

Dysregulation of immune response in otitis media

Objective

Otitis media (OM) is a common reason for children to be prescribed antibiotics and undergo surgery but a thorough understanding of disease mechanisms is lacking. We evaluate the evidence of a dysregulated immune response in the pathogenesis of OM.

Methods

A comprehensive systematic review of the literature using search terms [otitis media OR glue ear OR AOM OR OME] OR [middle ear AND (infection OR inflammation)] which were run through Medline and Embase via Ovid, including both human and animal studies. In total, 82 955 studies underwent automated filtering followed by manual screening. One hundred studies were included in the review.

Results

Most studies were based on in vitro or animal work. Abnormalities in pathogen detection pathways, such as Toll-like receptors, have confirmed roles in OM. The aetiology of OM, its chronic subgroups (chronic OM, persistent OM with effusion) and recurrent acute OM is complex; however, inflammatory signalling mechanisms are frequently implicated. Host epithelium likely plays a crucial role, but the characterisation of human middle ear tissue lags behind that of other anatomical subsites.

Conclusions

Translational research for OM presently falls far behind its clinical importance. This has likely hindered the development of new diagnostic and treatment modalities. Further work is urgently required; particularly to disentangle the respective immune pathologies in the clinically observed phenotypes and thereby work towards more personalised treatments.

Evaluation of the use of paired modified Wright's and periodic acid Schiff stains to identify microbial aggregates on cytological smears of dogs with microbial otitis externa and suspected biofilm

BACKGROUND

Micro-organisms associated with canine otitis externa (OE) may cause biofilm-associated infections (BAI). A key component of biofilm is microbial aggregate and extracellular polymeric substance (EPS). Periodic acid Schiff (PAS) can stain polysaccharide EPS in human otitis media with effusion, but this has not been tested in canine OE. There is no cytological definition for microbial aggregate, and definitive methods for identifying BAI in a clinical setting in canine OE have not been defined.

OBJECTIVES

To establish whether PAS stain can identify polysaccharide matrix on cytological smears; and to determine the reproducibility of identification of microbial aggregates within a discrete area of stained matrix, using paired modified Wright's and PAS-stained smears.

ANIMALS

Forty privately-owned dogs presenting to a dermatological referral practice.

METHODS AND MATERIALS

In this prospective, cross-sectional study, three investigators independently and blindly classified 40 paired modified Wright's-PAS slide sets into groups: aggregate-associated infection (AAI) and non-AAI (n = 27); and control (n = 13). Agreement between investigators for presence of AAI was measured using Fleiss' kappa statistic (FK). Agreement between investigators and dermatologists for presence of AAI upon cytological evaluation, and suspected BAI based on clinical examination, was measured using Cohen's kappa statistic.

RESULTS

The matrix was confirmed to stain PAS-positive. Interinvestigator agreement for AAI was very good using PAS (0.82 FK) and fair using modified-Wright's (MW) (0.33 FK). Reproducible cytological features associated with AAI were the presence of: three or more distinct aggregates (0.76 FK); discrete areas of PAS-positive matrix (0.70 FK); and the presence of high-density material (0.70 FK) using PAS stain.

CONCLUSION

PAS can stain the extracellular matrix on otic smears, and a novel protocol for reproducible identification of cytological features such as microbial aggregates has been established.

The Formation of Biofilm and Bacteriology in Otitis Media with Effusion in Children: A Prospective Cross-Sectional Study

BACKGROUND

Otitis media with effusion (OME) can cause serious complications such as hearing impairment or development delays. The aim of the study was to assess the microbiological profile of organisms responsible for OME and to determine if a biofilm formation can be observed.

METHODS

Ninety-nine samples from 76 patients aged from 6 months to 12 years were collected for microbiological and molecular studies.

RESULTS

In microbiological studies, pathogenic bacteria Haemophilus influenzae (38.89%), Streptococcus pneumoniae (33.33%), and Staphylococcus aureus MSSA (27.78%), as well as opportunistic bacteria Staphylococcus spp. (74.14%), Diphtheroids (20.69%), Streptococcus viridans (3.45%), and Neisseria spp. (1.72%) were found. The average degree of hearing loss in the group of children with positive bacterial culture was 35.9 dB, while in the group with negative bacterial culture it was 25.9 dB (p = 0.0008). The type of cultured bacteria had a significant impact on the degree of hearing impairment in children (p = 0.0192). In total, 37.5% of Staphylococcus spp. strains were able to form biofilm.

CONCLUSIONS

Staphylococcus spp. in OME may form biofilms, which can explain the chronic character of the disease. Pathogenic and opportunistic bacteria may be involved in the etiopathogenesis of OME. The degree of hearing loss was significantly higher in patients from which the positive bacterial cultures were obtained.

Inflammatory Mediator Profiles in Secretory Otitis Media in Relationship to Viable Bacterial Pathogens and Bacterial and Viral Nucleic Acids

Secretory otitis media (SOM) is characterized by persistence of fluid in the middle ear, often following an episode of acute otitis media. Our hypothesis is that failure to eliminate bacterial or viral pathogens may result in persistent low-grade inflammation. In this study, we analyzed inflammatory mediators in middle ear fluids from 67 children with SOM. This was combined with determinations of viable bacteria by culture along with detection of bacterial and viral genetic material by real-time polymerase chain reaction (PCR). The inflammatory mediators found at the highest concentrations (>30 ng/mL) were stem cell growth factor-β (median 110 ng/mL), CXCL1, IL-16, IL-8, migration inhibitory factor, CXCL10, and CXCL9. Among bacterial pathogens, Moraxella catarrhalis and Haemophilus influenzae dominated, regardless of detection methods, while rhinovirus dominated among viral pathogens. Middle ear fluid levels of interleukin (IL)-1α, IL-17, IL-1β, fibroblast growth factor basic, and tumor necrosis factor correlated strongly with presence of bacteria detected either by culture or PCR, while IL-1RA, IL-3, IL-6, IL-8, CCL3, CCL4, and granulocyte-colony stimulating factor correlated significantly with real-time PCR values. CXCL10, CXCL9, CCL2, and TRAIL correlated significantly with viral nucleic acid levels. To conclude, persistence of viral and bacterial pathogens may fuel persistent inflammation in SOM. Bacteria caused a broad inflammatory response, while viruses chiefly elicited the interferon-induced chemokines CXCL9 and CXCL10.

Otitis media with effusion is not a sterile inflammatory process: scanning electron microscope evidence

PURPOSE

We aimed to demonstrate whether chronic otitis media with effusion (OME) is a sterile condition or biofilms-related disease through direct visualization of middle ear mucosa by Scanning electron microscopy (SEM) and culture of the effusion.

METHODS

This case-control study included 60 children in two groups; the case group included 50 patients undergoing ventilation tube insertion (VTI) for Chronic OME (COME), and the control group included ten patients undergoing cochlear implantation (CI) surgery presenting normal middle ear mucosa. Biopsies from both groups' middle ear mucosa were evaluated for biofilm formation using scanning electron microscopy (SEM). Middle ear effusion (MEE) samples from COME patients were cultured on blood agar to detect and identify any bacterial growth. The adenoid size was evaluated and correlated to the biofilm formation in COME patients.

RESULTS

There was a significant difference between case and control groups regarding biofilm formation (p-value < 0.001*). Biofilm was evident in 84% of the COME patients (cases group) and absent in the control group. Only 12 COME patients (24%) had positive MEE culture, however, 76.2% of patients with biofilm had a negative culture. Streptococcus pneumonia was the most common otopathogen found either alone or combined with other otopathogens. There was a significant negative correlation between adenoid size and biofilm grade among the studied patients.

CONCLUSION

The visual identification of middle ear biofilms indicated their role in chronic OME. Middle ear biofilms need to be expected in children with OME, especially those who do not need adenoid surgery.

Allergy and Otitis Media in Clinical Practice

PURPOSE OF REVIEW

Otitis media (OM) is a disease with very high prevalence in infancy, substantial burden on healthcare resources, and relevant impact on the quality of life of families. The link between OM and allergy is controversial and still debated. However, a fundamental premise has to be placed before introducing this topic: there is the need to use clear and unambiguous terms. Literature abounds with misleading terms that significantly affect the methodology and consequently the outcomes. Moreover, it is essential to differentiate patients according to the OM type (i.e., acute OM, OM with effusion, and chronic suppurative OM), the allergic disease, and mainly the age.

RECENT FINDINGS

There are some recent studies exploring this issue through different approaches, such as epidemiological, mechanistic, and therapeutic. To identify allergy as a pathogenic factor for OM could improve the management of OM patients. Vice versa, to suspect allergy in OM patients could be reasonable in selected patients. The current narrative review provides an overview of the evidence concerning the potential role of allergy in OM. As there are conflicting findings, a possible interpretation of pathophysiological events and a pragmatic approach are proposed.

Bacterial aetiology of chronic otitis media with effusion in children - risk factors

Background

Otitis media with effusion (OME) may occur spontaneously because of poor Eustachian tube function or as an inflammatory response following AOM. Bacterial involvement in OME has been widely reported, with various available methods to identify pathogens from middle ear effusion, including traditional culture methods and polymerase chain reaction (PCR).

Objectives

The primary goal of this study was to evaluate the bacteriological profile of middle ear effusion in OME. Risk factors of the bacterial OME aetiology were also identified.

Methods

Middle ear effusions (MEF) from 50 children, aged 2–8 years, diagnosed by ENT and undergoing routine tympanostomy tube placement were collected. MEF samples were streaked on standard microbiological media. Next, DNA was isolated from MEF samples and analysed with multiplex PCR for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Alloiococcus otitidis.

Results

In multiplex PCR assay 37 (74%) of 50 children were positive for at least one of the four microorganisms. In 27.0% positive children multiple bacterial pathogens were identified. A. otitidis was the most frequently identified in positive MEF children (59.5%). By multiplex PCR, H. influenzae, S. pneumoniae and M. catarrhalis were detected in 24, 18 and 8% of OME patients, respectively. There was significant association between bilateral infection and H. influenzae aetiology of OME.

Conclusions

Overall we found OME predominantly a single otopathogen infection caused mainly by A. otitidis, which is difficult in identification using standard culture method, ahead to S. pneumoniae and H. influenzae. However, one third of MEF samples had multiple bacterial pathogens.

Bacterial Biofilm and its Role in the Pathogenesis of Disease

Recognition of the fact that bacterial biofilm may play a role in the pathogenesis of disease has led to an increased focus on identifying diseases that may be biofilm-related. Biofilm infections are typically chronic in nature, as biofilm-residing bacteria can be resilient to both the immune system, antibiotics, and other treatments. This is a comprehensive review describing biofilm diseases in the auditory, the cardiovascular, the digestive, the integumentary, the reproductive, the respiratory, and the urinary system. In most cases reviewed, the biofilms were identified through various imaging technics, in addition to other study approaches. The current knowledge on how biofilm may contribute to the pathogenesis of disease indicates a number of different mechanisms. This spans from biofilm being a mere reservoir of pathogenic bacteria, to playing a more active role, e.g., by contributing to inflammation. Observations also indicate that biofilm does not exclusively occur extracellularly, but may also be formed inside living cells. Furthermore, the presence of biofilm may contribute to development of cancer. In conclusion, this review shows that biofilm is part of many, probably most chronic infections. This is important knowledge for development of effective treatment strategies for such infections.

Haemophilus influenzae and Haemophilus parainfluenzae occurrence in the ear effusion in pediatric patients prone to recurrent respiratory tract infections (RRTI) and with otitis media with effusion (OME)

Introduction. Haemophilus influenzae and Haemophilus parainfluenzae are known as human-restricted respiratory microbiota representatives. The aim of the present paper was to assay haemophili prevalence in middle ear effusion specimens in pediatric patients with otitis media with effusion (OME).

Methods. A total of 86 ear effusion specimens (from the left and right ear independently) were collected from 43 pediatric patients with OME. For comparison, 58 nasopharyngeal specimens were taken from 58 pediatric patients prone to recurrent respiratory tract infections (RRTI). Isolation and identification of haemophili biotypes and antimicrobial susceptibility was accomplished by standard microbiological methods. The cell surface hydrophobicity (CSH) of isolates was assayed by the method of aggregation in ammonium sulfate (SAT).

Results. Haemophili were isolated in 25.6% (11/43) of all OME patients: in 5/43 (11.6%)– H. influenzae (biotypes II, III), in 5/43 (11.6%) – H. parainfluenzae, in 1/43 (2.3%) – both species were found. Haemophili-positive nasopharyngeal specimen was found in 27/58 (46.6%) RRTI patients: in 19/58 (32.8%) – H. influenzae, in 8/58 (13.8%) – H. parainfluenzae. About 90% of all haemophili isolates were characterised by extreme to strong CSH. Antimicrobial resistance occurred mainly among H. parainfluenzae (80%) and to a much lower percentage among H. influenzae (33.3%) isolates. The obtained data suggest that both H. influenzae and H. parainfluenzae can be involved in pathology of OME in pediatric patients. The high cell surface hydrophobicity can affect on the haemophili prevalence and ear colonization, and induces predisposition to the presence of these bacteria as a biofilm that serves as a virulence factor with great importance for the survival of these opportunistic bacteria and their persistence in the ear environment.

Respiratory Microbiota Predicts Clinical Disease Course of Acute Otorrhea in Children With Tympanostomy Tubes

BACKGROUND

Acute otitis media (AOM) is one of the most common childhood infections, generally thought to be caused by ascension of bacteria from the nasopharynx (NP) to the middle ear. Using 16S ribosomal RNA-based sequencing, we evaluated the relationship between the NP and middle ear fluid (MEF) microbiota in children with AOM with tympanostomy tubes (AOMT) as a proxy for AOM and explored whether microbiota profiling predicts natural disease course.

METHODS

Microbiota profiles of paired NP and MEF samples of 94 children below 5 years of age with uncomplicated AOMT were determined.

RESULTS

Local diversity (P < 0.001) and overall microbiota composition (P < 0.001) of NP and MEF samples differed significantly, although paired NP and MEF samples were much more similar than unpaired samples (P < 0.001). High qualitative agreement between the presence of individual bacteria in both niches was observed. Abundances of Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Turicella otitidis, Klebsiella pneumoniae and Haemophilus spp. were strongly correlated between the 2 niches. Additionally, P. aeruginosa, S. aureus, T. otitidis and Streptococcus pneumoniae abundance in NP were predictive of the presence of a range of oral types of bacteria in MEF. Interestingly, there was no association between Moraxella catarrhalis in NP and MEF samples, which was highly present in NP but virtually absent in MEF. Finally, the NP microbiota composition could predict duration of AOMT, even better than MEF microbiota.

CONCLUSIONS

We observed substantial correlations between paired NP and MEF microbiota in children with AOMT. Our data also suggest that NP microbiota profiling deserves further exploration as tool for future treatment decisions.

Role of Biofilms in Children with Chronic Adenoiditis and Middle Ear Disease

Chronic adenoiditis occurs frequently in children, and it is complicated by the subsequent development of recurrent or chronic middle ear diseases, such as recurrent acute otitis media, persistent otitis media with effusion and chronic otitis media, which may predispose a child to long-term functional sequalae and auditory impairment. Children with chronic adenoidal disease who fail to respond to traditional antibiotic therapy are usually candidates for surgery under general anaesthesia. It has been suggested that the ineffectiveness of antibiotic therapy in children with chronic adenoiditis is partially related to nasopharyngeal bacterial biofilms, which play a role in the development of chronic nasopharyngeal inflammation due to chronic adenoiditis, which is possibly associated with chronic or recurrent middle ear disease. This paper reviews the current evidence concerning the involvement of bacterial biofilms in the development of chronic adenoiditis and related middle ear infections in children.

Effect of Water Precautions on Otorrhea Incidence after Pediatric Tympanostomy Tube: Randomized Controlled Trial Evidence

Objectives

Tympanostomy with ventilation tube insertion is the most common otologic surgery. Many surgeons recommend water precautions, although its utility is questioned. We aimed to investigate if water precautions reduce the rate of otorrhea after transtympanic tube insertion.

Study Design

Multicenter randomized controlled trial.

Subjects and Methods

A total of 244 children aged 2 to 10 years undergoing their first set of Shepard tubes for otitis media with effusion and concomitant adenoidectomy were randomized to 2 groups: 1 with ear protection during water exposure (ear plugs and headbands, n = 130) and 1 without (n = 114). Bathing or swimming with unprotected ears was considered the exposure event and incidence of otorrhea, the primary outcome. Outcomes were assessed during the 6-month follow-up period.

Results

In the water precaution group, 32% had at least 1 episode of otorrhea as compared with 22% in the unprotected group, which was not statistically significant ( P = .09). Only 37% of the episodes of otorrhea in the protected group and 36% in the unprotected group had a temporal relation to water exposure (no difference, P = .81). Respectively, 56% and 52% of the episodes of otorrhea were in the context of upper respiratory tract infection. Global quality of life improved significantly, irrespective of whether water protection was prescribed.

Conclusion

The incidence of otorrhea was not different with or without prescription of ear protection during water exposure among children with tympanostomy tubes, which supports current guideline recommendations that routine water precautions are unnecessary in this population.

Evaluation of combinations of putative anti-biofilm agents and antibiotics to eradicate biofilms of Staphylococcus aureus and Pseudomonas aeruginosa

Objectives

To evaluate potential anti-biofilm agents for their ability to enhance the activity of antibiotics for local treatment of localized biofilm infections.

Methods

Staphylococcus aureus and Pseudomonas aeruginosa in vitro biofilm models were developed. The putative antibiotic enhancers N-acetylcysteine, acetylsalicylic acid, sodium salicylate, recombinant human deoxyribonuclease I, dispersin B, hydrogen peroxide and Johnson's Baby Shampoo (JBS) were tested for their anti-biofilm activity alone and their ability to enhance the activity of antibiotics for 7 or 14 days, against 5 day old biofilms. The antibiotic enhancers were paired with rifampicin and clindamycin against S. aureus and gentamicin and ciprofloxacin against P. aeruginosa. Isolates from biofilms that were not eradicated were tested for antibiotic resistance.

Results

Antibiotic levels 10× MIC and 100× MIC significantly reduced biofilm, but did not consistently eradicate it. Antibiotics at 100× MIC with 10% JBS for 14 days was the only treatment to eradicate both staphylococcal and pseudomonal biofilms. Recombinant human deoxyribonuclease I significantly reduced staphylococcal biofilm. Emergence of resistance of surviving isolates was minimal and was often associated with the small colony variant phenotype.

Conclusions

JBS enhanced the activity of antibiotics and several other promising anti-biofilm agents were identified. Antibiotics with 10% JBS eradicated biofilms produced by both organisms. Such combinations might be useful in local treatment of localized biofilm infections.

Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention

In an institutional review board-approved study, 25 pediatric subjects diagnosed with chronic or recurrent otitis media were observed over a period of six months with optical coherence tomography (OCT). Subjects were followed throughout their treatment at the initial patient evaluation and preoperative consultation, surgery (intraoperative imaging), and postoperative follow-up, followed by an additional six months of records-based observation. At each time point, the tympanic membrane (at the light reflex region) and directly adjacent middle-ear cavity were observed in vivo with a handheld OCT probe and portable system. Imaging results were compared with clinical outcomes to correlate the clearance of symptoms in relation to changes in the image-based features of infection. OCT images of most all participants showed the presence of additional infection-related biofilm structures during their initial consultation visit and similarly for subjects imaged intraoperatively before myringotomy. Subjects with successful treatment (no recurrence of infectious symptoms) had no additional structures visible in OCT images during the postoperative visit. OCT image findings suggest surgical intervention consisting of myringotomy and tympanostomy tube placement provides a means to clear the middle ear of infection-related components, including middle-ear fluid and biofilms. Furthermore, OCT was demonstrated as a rapid diagnostic tool to prospectively monitor patients in both outpatient and surgical settings.

Otitis media with effusion and atopy: is there a causal relationship?

Otitis Media with Effusion (OME) is an inflammatory condition of the middle ear cleft, acute or chronic, with collection of fluid in the middle ear with an intact tympanic membrane. It is a very common disease in childhood, the most frequent cause of hearing loss in childhood and often requiring surgery. OME is called chronic when the fluid in the middle ear persists for more than three months or when the episodes recur six or more times in one year. The current article covers various aspects of OME including definition, epidemiology. Pathomechanisms, risk factors, role of allergy in OME, impact of upper airway disease on OME, eosinophilic otitis media and management of OME.

Water protection after tympanostomy (Shepard) tubes does not decrease otorrhea incidence - retrospective cohort study

Introduction

Myringotomy for tube insertion is the most common otologic surgery. Otorrhea is a frequent complication of this procedure and, to prevent it, most surgeons strongly recommend avoiding contact with water as this is thought to adversely impact on post-operative quality of life.

Objective

To understand the benefit of this recommendation.

Methods

Observational study – retrospective cohort study comparing the incidence of post-operative otorrhea and its impact on patients’ quality of life, in two groups of patients comprising children under 10 years of age who underwent bilateral myringotomy and tube placement for chronic otitis media with effusion between May 2011 and May 2012. One group received water protection care after surgery, the other did not. Data was collected through telephonic interview, after one year of follow up (one year after the procedure). Water exposure without protection was considered the exposure event. Incidence of otorrhea and perceived impact on quality of life were the outcome measures. Results were compared after logistic regression.

Results

We included 143 children: 116 were not exposed to water without protection and 27 were exposed. In the not exposed group 36.2% had at least one episode of otorrhea, compared to 40.0% of the exposed group. Odds ratio for otorrhea on exposed was 1.21 (95% CI 0.51–2.85, p = 0.6). Negative impact on quality of life was reported by parents of 48.2% on the not exposed children, compared to 40.7% on the exposed group. This difference was not significant (p = 0.5).

Conclusion

We found that recommending water protection did not have beneficial effect on the incidence of otorrhea after myringotomy with tubes on chronic otitis media with effusion. However, such measures did not appear to have a negative impact on quality of life. This is a populational observational study with few cases (143 cases); these final statements would be better stated by a very large populational study with another large control group.

Interaction Between Allergy and Middle Ear Infection

PURPOSE OF REVIEW

Recent studies have attempted to identify interactions among the causes of otitis media with effusion (OME). This review discusses the interaction between allergy and infection with regard to host and environmental factors in terms of the development of OME.

RECENT FINDINGS

Protection of the upper airway against microbial invasion requires active interaction between the defense mechanisms of the respiratory epithelium, including innate and adaptive immunity, and mechanical factors. The impairment of these defenses due to allergy and/or increased bacterial resistance may lead to increased susceptibility to infectious organisms in the respiratory tract and middle ear mucosa. Recent genetic studies have provided valuable information about the association of Toll-like receptor signaling variations with clinical phenotypes and the risk of infection in the middle ear. Among the causal factors of OME, allergy not only induces an inflammatory reaction in the middle ear cavity but also facilitates the invasion of infectious pathogens. There is also evidence that allergy can affect the susceptibility of patients to infection of the upper respiratory tract, including the middle ear cavity.

Relationship of the Middle Ear Effusion Microbiome to Secretory Mucin Production in Pediatric Patients With Chronic Otitis Media

BACKGROUND

Acute otitis media, an infection of the middle ear, can become chronic after multiple episodes. Microbial influence on chronic otitis media remains unclear. It has been reported that mucin glycoproteins are required for middle ear immune defense against pathogens. We aim to characterize the middle ear effusion (MEE) microbiome using high-throughput sequencing and assess potential associations in microbiome diversity with the presence of the secretory mucins MUC5B and MUC5AC. We hypothesize that MEEs containing MUC5B will exhibit a microbiome largely devoid of typical acute otitis media bacteria.

METHODS

Fifty-five MEEs from children undergoing myringotomy at Children's National Health System were recovered. Mucin was semiquantitatively determined through Western blot analysis. DNA was subjected to 16S rRNA amplicon sequencing using the Illumina MiSeq platform. Raw data were processed in mothur (SILVA reference database). Alpha- and beta-diversity metrics were determined. Abundance differences between sample groups were estimated.

RESULTS

MUC5B was present in 94.5% and MUC5AC in 65.5% of MEEs. Sequencing revealed 39 genera with a relative abundance ≥0.1%. Haemophilus (22.54%), Moraxella (11.11%) and Turicella (7.84%) were the most abundant. Turicella and Pseudomonas proportions were greater in patients older than 24 months of age. In patients with hearing loss, Haemophilus was more abundant, while Turicella and Actinobacteria were less abundant. Haemophilus was also more abundant in samples containing both secretory mucins.

CONCLUSIONS

The microbiome of MEEs from children with chronic otitis media differs according to specific clinical features, such as mucin content, age and presence of hearing loss. These associations provide novel pathophysiologic insights across the spectrum of otitis media progression.

Bacterial Species and Antibiotic Sensitivity in Korean Patients Diagnosed with Acute Otitis Media and Otitis Media with Effusion

Changes over time in pathogens and their antibiotic sensitivity resulting from the recent overuse and misuse of antibiotics in otitis media (OM) have complicated treatment. This study evaluated changes over 5 years in principal pathogens and their antibiotic sensitivity in patients in Korea diagnosed with acute OM (AOM) and OM with effusion (OME). The study population consisted of 683 patients who visited the outpatient department of otorhinolaryngology in 7 tertiary hospitals in Korea between January 2010 and May 2015 and were diagnosed with acute AOM or OME. Aural discharge or middle ear fluid were collected from patients in the operating room or outpatient department and subjected to tests of bacterial identification and antibiotic sensitivity. The overall bacteria detection rate of AOM was 62.3% and OME was 40.9%. The most frequently isolated Gram-positive bacterial species was coagulase negative Staphylococcus aureus (CNS) followed by methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), and Streptococcus pneumonia (SP), whereas the most frequently isolated Gram-negative bacterium was Pseudomonas aeruginosa (PA). Regardless of OM subtype, ≥ 80% of CNS and MRSA strains were resistant to penicillin (PC) and tetracycline (TC); isolated MRSA strains showed low sensitivity to other antibiotics, with 100% resistant to PC, TC, cefoxitin (CFT), and erythromycin (EM); and isolated PA showed low sensitivity to quinolone antibiotics, including ciprofloxacin (CIP) and levofloxacin (LFX), and to aminoglycosides. Bacterial species and antibiotic sensitivity did not change significantly over 5 years. The rate of detection of MRSA was higher in OME than in previous studies. As bacterial predominance and antibiotic sensitivity could change over time, continuous and periodic surveillance is necessary in guiding appropriate antibacterial therapy.

Anti-confocal assessment of middle ear inflammation

To improve the diagnostic prediction of recurrence of otitis media with effusion after surgery, an anti-confocal system combined with spectroscopic measurements is proposed to reject unwanted signals from the eardrum and assess the blood content. The anti-confocal system was experimentally evaluated on both optical middle ear phantom and human skin. Results showed effective rejection of signals from the eardrum using a central stop replacing the confocal pinhole, while still detecting signals from the middle ear mucosa. The system is sensitive to changes in blood content, but scattering and absorption characteristics of the eardrum can distort the measurement. Confocal detection of eardrum properties was shown to be a promising approach to correct measurements.

MALDI-TOF mass spectrometry reveals a highly complex bacterial profile of otitis media with effusion

OBJECTIVES

With conventional microbiological methods, a significant proportion of middle ear effusion (MEE) proves to be sterile. Accurate molecular biological techniques have been used to identify only pathogenic bacteria. Matrix assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an adequate tool for the precise and simultaneous identification of a wide range of bacterial species from a small sample. The aim of this study was to explore the use of MALDI-TOF MS in revealing the frequency and complexity of bacterial flora in MEE in otitis media with effusion (OME).

METHODS

MEEs from 40 children with chronic otitis media with effusion were examined for 2000 pathogenic, facultative pathogenic and nonpathogenic bacterial species using MALDI-TOF MS. Two middle ear samples from children who underwent cochlear implantation with healthy middle ear were also examined in the same way.

RESULTS

No bacteria were found in healthy control samples and 92% of OME samples were positive for at least one bacterium. In 52% of the samples more than one bacterium was identified. In total 39 bacterial species were found in the middle ear samples. Of the positive samples 19% contained those pathogens which were previously thought to contribute OME.

CONCLUSION

MALDI-TOF MS is a suitable tool for identifying a wide range of bacterial species in MEE. Results show that bacterial flora of MEE in OME is more diverse and abundant than it was formerly thought. This previously unreported bacterial invasion may help to obtain proper understanding and therapy of OME.

Do Staphylococcus aureus superantigens play a role in the pathogenesis of otitis media with effusion in children?

OBJECTIVES

Staphylococcal enterotoxins (SEs), acting as superantigens, have been reported to be involved in the pathogenesis of chronic inflammatory diseases of the upper and lower airway. There has been no previous study investigating the role of SEs in otitis media with effusion (OME). Therefore, this study was designed to analyze middle ear aspirates from children with and without OME for the presence of SEs.

METHODS

Middle ear aspirates were obtained from 24 patients and 24 controls. All samples were processed for bacterial culture and detection of five staphylococcal SEs (SEA, SEB, SEC and SED) and toxic shock syndrome toxin-1 using the Rapid Latex Agglutination Test.

RESULTS

In bacterial culture assays, six samples (25%) of the study group and five samples (20.8%) of the control group showed bacterial growth. At least one SE was demonstrated in 6 of 24 patients and in 3 of 24 controls. There was no statistically significant difference between the two groups with respect to the presence of SEs.

CONCLUSION

Although there is evidence that SEs have a potential role in the pathogenesis of chronic inflammatory diseases, there is no evidence that the inflammation process is initiated by SEs in patients with OME.

ACE grading-A proposed endoscopic grading system for adenoids and its clinical correlation

OBJECTIVES

To propose a novel endoscopic adenoid grading system using a rigid nasal endoscope and to study its correlation with the clinical diagnosis.

METHODOLOGY

Prerecorded video clips of rigid nasal endoscopy taken during endoscopic adenoidectomy were retrieved. Otolaryngology consultants blinded to the clinical diagnosis of the child were presented these videos and asked to grade the adenoid hypertrophy as per the proposed endoscopic ACE (Airway/Choana/Eustachian tube) grading system. The clinical diagnosis was correlated with the different aspects of the descriptive endoscopic grading system.

RESULTS

152 video clips were presented to the otolaryngology consultants for grading. The average age was 8.6 years (SD-3.48), while the male female ratio was 3:2. The A subcomponent of the ACE grading showed significant correlation with the diagnosis of sleep disordered breathing and chronic adenotonsillitis, C subcomponent with sleep disordered breathing and the E subcomponent with the diagnosis of otitis media.

CONCLUSION

The proposed endoscopic grading is easily applicable and at the same time clearly describes the relation of the adenoids to the nasopharynx, choana and Eustachian tube. Different aspects of the grading system correlated differently with the clinical diagnosis emphasizing that a descriptive scoring rather than a comprehensive scoring is a more relevant clinical tool.

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.

Haemophilus influenzae biofilm formation in chronic otitis media with effusion

Otitis media with effusion (OME) is a highly prevalent disease in children, but the exact pathogenesis and role of bacteria are still not well understood. This study aimed to investigate the presence of otopathogenic bacteria in the middle ear effusion (MEE) and adenoid of children with chronic OME (COME), and to investigate in vivo whether these bacteria, especially Haemophilus influenzae, are organized as a biofilm in the middle ear fluid. MEE and adenoid samples were collected from 21 patients with COME. Extensive bacterial culturing and genotyping was performed on all middle ear and adenoid samples. Fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) was used to visualize possible biofilm structures for a selection of middle ear effusion samples. 34 MEE samples were collected from 21 patients of which 64.7 % were culture positive for bacteria and 47.0 % were culture positive for Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and/or Streptococcus pneumoniae. All 21 adenoid samples were culture positive for one or more of these four otopathogens. H. influenzae (35.3 %) and S. pneumoniae (76.2 %) were the most frequently cultured bacteria in the MEE and adenoid samples, respectively. The same bacterial species was found in MEE and adenoid for 84.6 % of the patients and in 81.2 % of the cases where the same species was found in more than one site it involved the same bacterial genotype. FISH and CLSM demonstrated the presence of H. influenzae specific biofilm structures in five of the eight culture positive MEEs that were tested, but in none of the two culture negative MEEs. The findings in this study indicate that the adenoid acts as a reservoir for bacteria in MEE and confirms that biofilms, in at least half of the cases consisting of H. influenzae, are indeed present in the MEE of children with COME. Biofilms may thus play a crucial role in the pathogenesis of COME, which is important in the understanding of this disease and the development of potential future treatment options.

Detection of bacteria in middle ear effusions based on the presence of allergy: does allergy augment bacterial infection in the middle ear?

Background

Bacterial infection, Eustachian tube dysfunction, allergies, and immunologic factors are major causes of otitis media with effusion (OME). However, the exact pathogenesis of OME is still unclear. This study evaluated whether allergy influences bacterial growth in middle ear effusions.

Materials

Fifty-four samples were obtained from OME patients 3–10 years of age who underwent ventilation tube insertion and were divided into two groups based on the presence of allergy as determined using the multiple allergosorbent test (MAST). Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis bacterial DNA in the middle ear effusions was analyzed using polymerase chain reaction. Overall detection rates and those for each species were compared between the two groups.

Results

Of the 54 middle ear effusion samples, 38 (70.4 %) contained bacterial DNA and 14 (36.8 %) of these contained DNA from multiple species. S. pneumoniae was detected in 27 samples (50 %), H. influenzae in 17 samples (31.4 %), and M. catarrhalis in 9 samples (16.6 %). There was no significant difference in the bacterial detection rates between the middle ear effusions of the MAST-positive and MAST-negative groups.

Conclusion

The rate of bacteria detection in middle ear effusions did not differ between allergic and non-allergic children.

Anti-confocal versus confocal assessment of the middle ear simulated by Monte Carlo methods

The ability to monitor the inflammatory state of the middle ear mucosa would provide clinical utility. To enable spectral measurements on the mucosa whilst rejecting background signal from the eardrum an anti-confocal system is investigated. In contrast to the central pinhole in a confocal system the anti-confocal system uses a central stop to reject light from the in-focus plane, the eardrum, with all other light detected. Monte Carlo simulations of this system show an increase in detected signal and improved signal-to-background ratio compared to a conventional confocal set-up used to image the middle ear mucosa. System parameters are varied in the simulation and their influence on the level of background rejection are presented.

Do orally administered antibiotics reach concentrations in the middle ear sufficient to eradicate planktonic and biofilm bacteria? A review

INTRODUCTION

Infectious conditions of the middle ear are a common and significant cause of morbidity and mortality worldwide. Systemic antibiotics are frequently used, but their effectiveness will depend on whether an adequate antibiotic concentration is achieved in the middle ear; this is especially important in biofilm infections such as otitis media with effusion (OME), where high antibiotic concentrations are typically required for effective treatment.

OBJECTIVE

This review examines what antibiotic levels can be reached in the middle ear with oral administration, as a means of guiding rational antibiotic choice in the clinic and future research, and to determine whether levels high enough for biofilm eradication are reached.

METHODS

A literature search of studies measuring levels of antibiotics in the plasma and in the middle ear after oral administration was conducted. These levels were compared to the minimum inhibitory concentrations (MIC) provided by the European Committee for Antimicrobial Susceptibility Testing (EUCAST) to determine if antibiotic doses were reaching sufficient levels to inhibit planktonic bacteria. The middle ear concentrations were then calculated as a multiple of the MIC to determine if the concentrations were reaching biofilm eradication concentrations (typically up to 1000×MIC).

RESULTS

The highest antibiotic levels against Staphylococcus aureus reach 8.3×MIC, against Moraxella catarrhalis 33.2×MIC, against Haemophilus influenzae 31.2×MIC, and against Streptococcus pneumoniae 46.2×MIC. The macrolide antibiotics reach higher levels in the middle ear than in plasma.

CONCLUSIONS

Orally administered antibiotics reach levels above the MIC in the middle ear. However, they do not reach levels that would be likely to eradicate biofilms.

Diseases of the middle ear in childhood

Middle ear diseases in childhood play an important role in daily ENT practice due to their high incidence. Some of these like acute otitis media or otitis media with effusion have been studied extensively within the last decades. In this article, we present a selection of important childhood middle ear diseases and discuss the actual literature concerning their treatment, management of complications and outcome. Another main topic of this paper deals with the possibilities of surgical hearing rehabilitation in childhood. The bone-anchored hearing aid BAHA(®) and the active partially implantable device Vibrant Soundbridge(®) could successfully be applied for children. In this manuscript, we discuss the actual literature concerning clinical outcomes of these implantable hearing aids.

Role of biofilm in children with recurrent upper respiratory tract infections

Recurrent respiratory tract infections (RRTIs) are very common in children and a major challenge for pediatricians. In the last few years, bacterial biofilms have been linked to RRTIs and antibiotic resistance, and have raised serious concerns regarding the therapeutic management of recurrent middle ear diseases, chronic rhinosinusitis, and recurrent pharyngotonsillitis. This paper aims to review the new insights into biofilm-related upper respiratory tract infections in children and possible therapeutic strategies. It focuses on the clinical implications for recurrent disease and on studies in pediatric patients. Analysis of the literature showed that the involvement of bacterial biofilm in recurrent upper airway tract infections is an emerging problem that may lead to serious concerns about infection control. Despite the large amount of research within this field, detailed insight into the complex structure of bacterial biofilms and the ultrastructural and biochemical mechanisms responsible for its evasion of the immune system and resistance to treatments is currently lacking. In the future, additional emphasis should be placed on biofilm management as a component of therapeutic strategies. This goal can be attained by finding feasible methods for detecting biofilms in vivo and identifying effective methods for administering treatments that eradicate preexisting bacterial biofilms or hinder bacterial adhesion to respiratory cells.

Otitis media: an update on current pharmacotherapy and future perspectives

INTRODUCTION

Acute otitis media (AOM) is the most common childhood bacterial infection and also the leading cause of conductive hearing loss in children. Currently, there is an urgent need for developing novel therapeutic agents for treating AOM.

AREAS COVERED

Structured search of current literature. PubMed was searched for published literature in areas of pharmacotherapeutics, preventive therapies and complementary treatments for OM. The intent of this review is to provide a comprehensive evaluation of therapeutics for AOM, including preventive modalities and complementary medicine.

EXPERT OPINION

the management of AOM in young children is still evolving and depends on patterns of bacterial colonization and antimicrobial resistance in the community. The introduction of vaccinations against potential respiratory tract pathogens has altered the frequency of recovery of pathogens causing ear infections in children. Even though not all patients require antimicrobial therapy to overcome their infection, these agents improve symptoms faster and lead to fewer treatment failures. Further studies are warranted to evaluate which patients would best benefit from antimicrobial therapy.

Spore formation and toxin production in Clostridium difficile biofilms

The ability to grow as a biofilm can facilitate survival of bacteria in the environment and promote infection. To better characterize biofilm formation in the pathogen Clostridium difficile, we established a colony biofilm culture method for this organism on a polycarbonate filter, and analyzed the matrix and the cells in biofilms from a variety of clinical isolates over several days of biofilm culture. We found that biofilms readily formed in all strains analyzed, and that spores were abundant within about 6 days. We also found that extracellular DNA (eDNA), polysaccharide and protein was readily detected in the matrix of all strains, including the major toxins A and/or B, in toxigenic strains. All the strains we analyzed formed spores. Apart from strains 630 and VPI10463, which sporulated in the biofilm at relatively low frequencies, the frequencies of biofilm sporulation varied between 46 and 65%, suggesting that variations in sporulation levels among strains is unlikely to be a major factor in variation in the severity of disease. Spores in biofilms also had reduced germination efficiency compared to spores obtained by a conventional sporulation protocol. Transmission electron microscopy revealed that in 3 day-old biofilms, the outermost structure of the spore is a lightly staining coat. However, after 6 days, material that resembles cell debris in the matrix surrounds the spore, and darkly staining granules are closely associated with the spores surface. In 14 day-old biofilms, relatively few spores are surrounded by the apparent cell debris, and the surface-associated granules are present at higher density at the coat surface. Finally, we showed that biofilm cells possess 100-fold greater resistance to the antibiotic metronidazole then do cells cultured in liquid media. Taken together, our data suggest that C. difficile cells and spores in biofilms have specialized properties that may facilitate infection.

Update on otitis media - prevention and treatment

Acute otitis media and otitis media with effusion are common childhood disorders, a source of significant morbidity, and a leading cause of antibiotic prescription in primary health care. Although effective treatments are available, some shortcomings remain, and thus better treatments would be welcome. Recent discoveries within the field of otitis media research relating to its etiology and pathogenesis have led to further investigation aimed at developing novel treatments. This article provides a review of the latest evidence relating to the understanding of acute otitis media and otitis media with effusion, current treatment strategies, their limitations, new areas of research, and novel strategies for treatment.

Decreased Expression of TLR-9 and Cytokines in the Presence of Bacteria in Patients with Otitis Media with Effusion

Objectives

Toll-like receptor (TLR)-9 recognizes unmethylated cytidine-phosphate-guanosine (CpG) motifs in bacteria. Therefore, the expression of TLR-9 may differ according to the results of bacterial culture, and thus a change in proinflammatory cytokine induction can also be expected. The authors aimed to assess the differences and relationships between the expression of TLR-9, cytokines, and nitric oxide synthase (NOS) in otitis media with effusion (OME) based on bacterial culture results.

Methods

Sixty-eight patients with OME were divided into culture-positive and culture-negative groups based on middle ear culture results. mRNA expression of TLR-9, NOS, and cytokines was measured and analyzed.

Results

Bacteria were detected in 38.2% of patients, and the distribution was as follows: coagulase negative Staphylococcus (10.3%), Staphylococcus aureus (8.8%), Streptococcus pneumonia (5.9%), and Bacillus spp. and Haemophilus influenza combined (2.9%). There were no significant differences in epidemiologic characteristics according to the culture results. Down-regulation of TLR-9 was observed in the culture-positive group (P=0.019). Cytokines including interleukin (IL)-12 (r=-0.582), tumor necrosis factor (TNF)-α (r=-0.569), interferon (IFN)-γ (r=-0.442), IL-6 (r=-0.395) and inducible NOS (r=-0.256) tended to decrease with the detection of bacteria.

Conclusion

The expression of TLR-9 significantly decreased in OME with confirmed bacterial pathogens. IL-12, TNF-α, IFN-β, IL-6 expression tended to decrease with the detection of bacteria. The presence of bacterial pathogens in OME may be related to abnormalities in the innate immune system.

The role of the human microbiome in otolaryngology-head and neck surgery: a contemporary review

OBJECTIVES/HYPOTHESIS

The human microbiome represents the collective genomes and gene products of microbes living within and on humans. The objective of this review is to provide a summary of the current microbiome literature pertaining to otolaryngology-head and neck surgery.

DATA SOURCE

Ovid MEDLINE.

METHODS

Scientific publications with clinical correlates.

RESULTS

Human microbiome studies have been facilitated by culture-independent, high-throughput sequencing methods. Data from the Human Microbiome Project has shown that the composition of the human microbiome is specific to each body site and that each individual has a unique microbiome. Alterations in the human microbiome are associated with some disease states; thus, novel therapeutic strategies are being developed based on concepts and findings stemming from microbiome research.

CONCLUSIONS

Although a growing body of research shows potential significance of the human microbiome for human health and disease, there is a paucity of microbiome studies in otolaryngology. More studies are required to increase our understanding of the indigenous microbiota and their effects on diseases of the head and neck.

Antibiotics for Otitis Media with Effusion in Children

The "Cochrane Corner" is a quarterly section in the journal that highlights systematic reviews relevant to otolaryngology-head and neck surgery, with invited commentary to aid clinical decision making. This installment features a Cochrane Review, "Antibiotics for Otitis Media with Effusion in Children," that does not support the routine use of antibiotics for treating otitis media with effusion in children. Although children treated with antibiotics had higher rates of effusion resolution, there was no impact on hearing levels or the need for tympanostomy tubes.