Microbial profiling does not differentiate between childhood recurrent acute otitis media and chronic otitis media with effusion

A novel immuno-molecular strategy for the detection of Streptococcus pneumoniae serotypes in human cerebrospinal and middle ear fluids

Streptococcus pneumoniae is one of the most common microorganisms causing acute otitis media (AOM) in children. While bacterial culture of middle ear fluid (MEF) is the gold standard to detect the etiological organisms, several host and pathogen factors impact the survival of the organisms resulting in false negatives. To overcome this limitation, we have developed and validated an innovative multiplex immuno-molecular assay to screen and detect the S. pneumoniae 15-valent pneumococcal conjugate vaccine (PCV15; STs 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) vaccine serotypes in MEF. This novel in vitro approach involves two-step testing. First, the MEF specimens were tested for highly conserved pneumococcal genes, autolysin, lytA, and pneumolysin, ply using direct PCR to identify pneumococcus positive specimens. The pneumococcus positive specimens were screened for the presence of vaccine serotype specific pneumococcal polysaccharides using a 15-plex Pneumococcal Antigen Detection (PAD) assay, with specific capture and detection monoclonal antibodies. Due to the lack of availability of MEF samples, cerebrospinal fluid (CSF) was used as the surrogate matrix for the development and validation of the PCR-PAD assays. The PCR and PAD assays were separately evaluated for sensitivity and specificity. Subsequently, the PCR-PAD assays were cross-validated with human MEF samples (n = 39) which were culture confirmed to contain relevant bacterial strains. The combined PCR-PAD assays demonstrated high rate of agreement 94.9% (95% CI; 82.7, 99.4%) with historical Quellung serotype data of these MEF samples. This novel PCR-PAD assay demonstrates the feasibility of combining molecular and immunological assays to screen and identify PCV15 pneumococcal vaccine serotypes in AOM clinical samples.

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.

Surgery for adenotonsillar hypertrophy and otitis media in children is less demanded in quarantine times

OBJECTIVES

In the COVID-19 era, extreme measures of social distancing have contained the spread of common viral respiratory infections, which are involved in the pathogenesis of Adenotonsillar Hypertrophy (ATH), and Chronic Otitis Media with Effusion (COME), the two commonest chronic ENT diseases of childhood. This study examines the lockdown effect on the number of procedures performed for these two conditions.

METHODS

The consecutive charts of 650 and 195 children being operated respectively for ATH and COME during the quarantine (05/2020-02/2021) and unrestrained (05/2019-02/2020) periods were retrospectively reviewed. Surgical treatment of ankyloglossia, performed in 103 patients during the same periods was employed as a control procedure.

RESULTS

Adenotonsillectomies and tympanostomies significantly decreased in the lockdown phase by 52% (P < 0.001) and 74% (P < 0.001), respectively, whereas control procedure counts increased by 25%. In terms of seasonal variation, ATH-related surgeries were significantly reduced during the winter season of the pandemic by 73% (P < 0.001), in comparison with the corresponding months of the unrestrained period. School-aged children received significantly fewer operations for ATH (-59%) than preschoolers (-42%), as a result of the lockdown (P = 0.044).

CONCLUSION

When the child's exposure to respiratory pathogens is minimal, as in the case of lockdown, a noticeable decline occurs in the incidence of ATH and COME indicated for surgical treatment. Chronic low-grade inflammation, boosted by repetitive viral infections seems to underlie both conditions. Timely, effective isolation measures might reverse the disease process and keep the child away from the Operating Room.

Predominant Bacterial and Viral Otopathogens Identified Within the Respiratory Tract and Middle Ear of Urban Australian Children Experiencing Otitis Media Are Diversely Distributed

Background

Otitis media (OM) is one of the most common infections in young children, arising from bacterial and/or viral infection of the middle ear. Globally, Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) are the predominant bacterial otopathogens. Importantly, common upper respiratory viruses are increasingly recognized contributors to the polymicrobial pathogenesis of OM. This study aimed to identify predominant bacteria and viruses in the nasopharynx, adenoids and middle ears of peri-urban/urban South-East Queensland Australian children, with and without clinical history of chronic otitis media with effusion (COME) and/or recurrent acute otitis media (RAOM).

Methods

Sixty children, 43 diagnosed with OM and 17 controls with no clinical history of OM from peri-urban/urban South-East Queensland community were recruited to the study. Respiratory tract bacterial and viral presence were examined within nasopharyngeal swabs (NPS), middle ear effusions (MEE) and adenoids, using real-time polymerase chain reaction (RT-PCR) and bacterial culture.

Results

At least one otopathogen present was observed in all adenoid samples, 86.1% and 82.4% of NPS for children with and without OM, respectively, and 47.1% of the MEE from the children with OM. NTHi was the most commonly detected bacteria in both the OM and control cohorts within the adenoids (90.0% vs 93.8%), nasopharynx (67.4% vs 58.8%) respectively, and in the MEE (OM cohort 25.9%). Viruses were detected in all adenoid samples, 67.4% vs 47.1% of the NPS from the OM and control cohorts, respectively, and 37% of the MEE. Rhinovirus was the predominant virus identified in the adenoids (85.0% vs 68.8%) and nasopharynx (37.2% vs 41.2%) from the OM and control cohorts, respectively, and the MEE (19.8%).

Conclusions

NTHi and rhinovirus are predominant otopathogens within the upper respiratory tract of children with and without OM from peri-urban and urban South-East Queensland, Australia. The presence of bacterial otopathogens within the middle ear is more predictive of concurrent URT infection than was observed for viruses, and the high otopathogen carriage within adenoid tissues confirms the complex polymicrobial environment in children, regardless of OM history.

Identification of the Bacterial Pathogens in Children with Otitis Media: A Study in the Northwestern Portuguese District of Braga

Understanding the bacterial etiology of otitis media (OM) is important when designing and evaluating the best course of treatment. This study analyzed middle ear fluid (MEF) and nasopharynx (NP) samples collected from 49 children with OM undergoing myringotomy in the northwestern Portuguese district of Braga. A correlation between species in the NP and MEF was observed following pathogen detection by culture and quantitative polymerase chain reaction (qPCR) methods. Bacterial identification using culturing methods showed that Moraxella catarrhalis was the most representative in NP and MEF, followed by Streptococcus pneumoniae. However, qPCR of MEF showed a higher prevalence (61%) of Haemophilus influenzae. S. pneumoniae was not the most frequently identified species, but it still remains one of the leading causes of OM in this region despite 93.9% of the children being vaccinated with the pneumococcal conjugate vaccine. Furthermore, 46% of the samples analyzed by qPCR identified more than two bacterial species. M. catarrhalis and S. pneumoniae were the most frequent combination identified in NP and MEF samples by culturing methods. Additionally, a few NP and MEF samples simultaneously presented the three main otopathogens. These results point out that polymicrobial infections play an important role in OM. Further studies characterizing the serotypes of the strains isolated, their resistance profile, and their biofilm forming ability would help in the development of more targeted strategies against otitis media.

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.

Review of otitis media microbiome studies: What do they tell us?

OBJECTIVES

To provide a state of the art review on accruing studies focused on defining the middle ear microbiome, highlighting the relationship of the microbiome to disease pathophysiology.

DATA SOURCES

Pubmed indexed peer-reviewed articles and published textbooks.

REVIEW METHODS

Comprehensive review of the literature using the following search terms: "microbiome" "bacterial pathogens" with the term "otitis media," and "middle ear."

RESULTS

A multitude of microbiome studies have been published in the recent past. In general findings from these studies underscore distinct profiles based on disease category. The adenoidal reservoir theory may not explain all etiologies of middle ear effusion production. The host immune system appears to be associated to the bacterial population identified in the middle ear space. Atopic respiratory diseases correlate to the middle ear microbiome. Some novel middle ear bacterial genera may be protective in terms of disease.

CONCLUSION

The understanding of otitis media disease progression pathophysiology is evolving, informed by accruing middle ear microbiomic data. The functional implications of middle ear microbiome findings need to be studied further. This may help counterbalance probiotic vs antibiotic approaches to disease mitigation.

Niche- and Gender-Dependent Immune Reactions in Relation to the Microbiota Profile in Pediatric Patients with Otitis Media with Effusion

Otitis media with effusion (OME) is a common inflammatory disease that primarily affects children. OME is defined as a chronic low-grade inflammation of the middle ear (ME), without any signs of infection and with effusion persisting in the ME for more than 3 months. The precise pathogenesis is, however, not fully understood. Here, we comprehensively characterized and compared the host immune responses (inflammatory cells and mediators) and the overall microbial community composition (microbiota) present in matched middle ear effusion (MEE) samples, external ear canal (EEC) lavages, and nasopharynx (NPH) samples from children with OME.

Otitis media with effusion (OME) is a common inflammatory disease that primarily affects children. OME is defined as a chronic low-grade inflammation of the middle ear (ME), without any signs of infection and with effusion persisting in the ME for more than 3 months. The precise pathogenesis is, however, not fully understood. Here, we comprehensively characterized and compared the host immune responses (inflammatory cells and mediators) and the overall microbial community composition (microbiota) present in matched middle ear effusion (MEE) samples, external ear canal (EEC) lavages, and nasopharynx (NPH) samples from children with OME. Female patients had significantly increased percentages of T lymphocytes and higher levels of a wide array of inflammatory mediators in their MEE compared to that of male patients, which were unrelated to microbiota composition. The relative abundances of identified microorganisms were strongly associated with their niche of origin. Furthermore, specific inflammatory mediators were highly correlated with certain bacterial species. Interestingly, some organisms displayed a niche-driven inflammation pattern in which presence of Haemophilus spp. and Corynebacterium propinquum in MEE was accompanied by proinflammatory mediators, whereas their presence in NPH was accompanied by anti-inflammatory mediators. For Turicella and Alloiococcus, we found exactly the opposite results, i.e., an anti-inflammatory profile when present in MEE, whereas their presence in the the NPH was accompanied by a proinflammatory profile. Together, our results indicate that immune responses in children with OME are highly niche- and microbiota-driven, but gender-based differences were also observed, providing novel insight into potential pathogenic mechanisms behind OME.

Design and Characterization of Protein E-PilA, a Candidate Fusion Antigen for Nontypeable Haemophilus influenzae Vaccine

Nontypeable Haemophilus influenzae (NTHi) is a pathogen known for being a frequent cause of acute otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. In the present study, a vaccine antigen based on the fusion of two known NTHi adhesive proteins, protein E (PE) and a pilin subunit (PilA), was developed. The quality of the combined antigen was investigated through functional, biophysical, and structural analyses.

Nontypeable Haemophilus influenzae (NTHi) is a pathogen known for being a frequent cause of acute otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. In the present study, a vaccine antigen based on the fusion of two known NTHi adhesive proteins, protein E (PE) and a pilin subunit (PilA), was developed. The quality of the combined antigen was investigated through functional, biophysical, and structural analyses. It was shown that the PE and PilA individual structures are not modified in the PE-PilA fusion and that PE-PilA assembles as a dimer in solution, reflecting PE dimerization. PE-PilA was found to bind vitronectin by enzyme-linked immunosorbent assay, as isolated PE does. Disulfide bridges were conserved and homogeneous, which was determined by peptide mapping and top-down analysis of PE, PilA, and PE-PilA molecules. Finally, the PE-PilA crystal showed a PE entity with a three-dimensional (3D) structure similar to that of the recently published isolated PE, while the structure of the PilA entity was similar to that of a 3D model elaborated from two other type 4 pilin subunits. Taken together, our observations suggest that the two tethered proteins behave independently within the chimeric molecule and display structures similar to those of the respective isolated antigens, which are important characteristics for eliciting optimal antibody-mediated immunity. PE and PilA can thus be further developed as a single fusion protein in a vaccine perspective, in the knowledge that tethering the two antigens does not perceptibly compromise the structural attributes offered by the individual antigens.

A Protein E-PilA Fusion Protein Shows Vaccine Potential against Nontypeable Haemophilus influenzae in Mice and Chinchillas

PE-PilA is a fusion protein composed of immunologically relevant parts of protein E (PE) and the majority subunit of the type IV pilus (PilA), two major antigens of nontypeable Haemophilus influenzae (NTHi). Here we report on the preclinical evaluation of PE-PilA as a vaccine antigen. The immunogenic potential of the PE and PilA within the fusion was compared with that of isolated PE and PilA antigens.

PE-PilA is a fusion protein composed of immunologically relevant parts of protein E (PE) and the majority subunit of the type IV pilus (PilA), two major antigens of nontypeable Haemophilus influenzae (NTHi). Here we report on the preclinical evaluation of PE-PilA as a vaccine antigen. The immunogenic potential of the PE and PilA within the fusion was compared with that of isolated PE and PilA antigens. When injected intramuscularly into mice, the immunogenicity of PE within the fusion was equivalent to that of isolated PE, except when it was formulated with alum. In contrast, in our murine models PilA was consistently found to be more immunogenic as a subentity of the PE-PilA fusion protein than when it was injected as an isolated antigen. Following immunization with PE-PilA, anti-PE antibodies demonstrated the same capacity to inhibit the binding of PE to vitronectin as those induced after PE immunization. Likewise, PE-PilA-induced anti-PilA antibodies inhibited the formation of NTHi biofilms and disrupted established biofilms in vitro. These experiments support the immunogenic equivalence between fused PE-PilA and isolated PE and PilA. Further, the potential of PE-PilA immunization against NTHi-induced disease was evaluated. After intranasal NTHi challenge, colonization of the murine nasopharynx significantly dropped in animals formerly immunized with PE-PilA, and in chinchillas, signs of otitis media were significantly reduced in animals that had received anti-PE-PilA antibodies. Taken together, our data support the use of PE-PilA as an NTHi vaccine antigen.

Nasal microbial composition and chronic otitis media with effusion: A case-control study

OBJECTIVES

Chronic otitis media with effusion (COME) in children can cause prolonged hearing loss, which is associated with an increased risk of learning delays and behavioural problems. Dispersal of bacterial pathogens from the nasal passages to the middle ear is implicated in COME. We sought to determine whether there is an association between nasal microbial composition and COME in children.

METHODS

A case-control study of children aged 3 and 4 years was conducted. Cases undergoing placement of tympanostomy tubes for COME were compared to healthy controls. Nasal swabs were collected and a questionnaire was administered. The V1-3 region of the 16S rRNA gene was amplified, and sequenced on the Illumina MiSeq.

RESULTS

73 children with COME had a lower Shannon diversity index than 105 healthy controls (1.62 [.80] versus 1.88 [.84], respectively; P = .046). The nasal microbiota of cases and controls differed in composition using Bray-Curtis dissimilarity (p = 0.002). Children with COME had a higher abundance of otopathogens and lower abundance of commensals including alpha haemolytic Streptococci and Lactococcus. Cluster analysis revealed 4 distinct nasal microbial profiles. Profiles that were Corynebacterium-dominated (aOR 4.18 [95%CI, 1.68-10.39], Streptococcus-dominated (aOR 3.12 [95%CI, 1.08-9.06], or Moraxella-dominated (aOR 4.70 [95%CI, 1.73-12.80] were associated with COME, compared to a more mixed microbial profile when controlling for age, ethnicity, and recent antibiotics use.

CONCLUSIONS

Children with COME have a less diverse nasal microbial composition with a higher abundance of pathogens, compared to healthy children who have a more mixed bacterial profile with a higher abundance of commensals. Further research is required to determine how nasal microbiota may relate to the pathogenesis or maintenance of COME, and whether modification of the nasal microbiota can prevent or treat children at risk of COME.

Resistant Streptococcus pneumoniae strains in children with acute otitis media- high risk of persistent colonization after treatment

Background

Despite advances in the development of pneumococcal conjugate vaccines, acute otitis media (AOM) is a common childhood infection, caused mainly by Streptococcus pneumoniae. It has been suggested that persistence of pneumococcal nasopharyngeal carriage is a risk factor for subsequent recurrent infections.

Methods

In this study we evaluate the relationship between 55 pneumococcal strains obtained from nasopharynx/oropharynx (NP/OP) and middle ear fluid (MEF) of 62 children, aged between 1 and 16 years, during AOM (including recurrent/treatment failure AOM, and post-treatment visits), based on their phenotypic and genotypic characteristics performed by analyses of serotype, antibiotic susceptibility patterns and multilocus sequence typing.

Results

S.pneumoniae was isolated from 27.4% of MEF samples; it constituted 43.6% of all positive bacterial samples from MEF samples. There was statistically significant concordance between isolation from the MEF sample and NP/OP colonization by S. pneumoniae (p < 0.0001). During post-treatment visits S.pneumoniae was isolated from 20.8% of children; 91% of them were positive in pneumococcal NP/OP culture during AOM. The serotypes belonging to 10- and 13-valent pneumococcal conjugated vaccines constituted 84% and 92% of the strains, respectively. Multidrug resistance was found in 84% of the strains. According to multivariate analysis, pneumococcal colonization after antibiotic therapy was significantly associated with shorter length of therapy in children with bilateral AOM.

Conclusions

High persistent prevalence of antibiotic-resistant S.pneumoniae strains in children with AOM after unsuccessful bacterial eradication may presumably be regarded as a predisposing factor of infection recurrence.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3398-9) contains supplementary material, which is available to authorized users.

Microbial otitis media: recent advancements in treatment, current challenges and opportunities

Otitis media (OM) is a common disease affecting humans, especially paediatric populations. OM refers to inflammation of the middle ear and can be broadly classified into two types, acute and chronic. Bacterial infection is one of the most common causes of OM. Despite the introduction of vaccines, the incidence of OM remains significantly high worldwide. In this mini-review article, we discuss the recent treatment modalities for OM, such as suspension gel, transcutaneous immunization, and intranasal and transtympanic drug delivery, including therapies that are currently undergoing clinical trials. We provide an overview of how these recent advancements in therapeutic strategies can facilitate the circumvention of current treatment challenges involving preadolescence soft palate dysfunction, biofilm formation, tympanic membrane (ear drum) barrier and the attainment of efficacious drug concentrations in the middle ear. While traditional first-line immunization strategies are generally not very efficacious against biofilms, new technologies that use transdermal or intranasal drug delivery via chitosan-PsaA nanoparticles have shown promising results in experimental animal models of OM. Sustained drug delivery systems such as penta-block copolymer poloxamer 407-polybutylphosphoester (P407-PBP) or poloxamer 407 (e.g. OTO-201, with the brand name 'OTIPRIO') have demonstrated that treatments can be reduced to a single topical application. The emergence of effective new treatment modalities opens up promising new avenues for the treatment of OM that could lead to improved quality of life for many children and their families.

Characterization of the nasopharyngeal and middle ear microbiota in gastroesophageal reflux-prone versus gastroesophageal reflux non-prone children

Otitis media (OM) is one of the most common pediatric infections worldwide, but the complex microbiology associated with OM is poorly understood. Previous studies have shown an association between OM and gastroesophageal reflux (GER) in children. Therefore, in order to bridge the gap in our current understanding of the interaction between GER and OM, we investigated the nasopharyngeal and middle ear microbiota of children suffering from GER-associated OM and OM only, using culture-independent 16S rRNA gene sequencing. Middle ear fluid, nasopharyngeal swabs, and clinical data were collected as part of a prospective pilot study conducted at the Department of Otorhinolaryngology of the Erasmus MC-Sophia Children's Hospital, Rotterdam, the Netherlands. A total of 30 children up to 12 years of age who suffered from recurrent acute otitis media (AOM) (5), chronic otitis media with effusion (OME) (23), or both (2), and who were listed for tympanostomy tube placement, were included in the study. Nine children were included in the GER-associated OM cohort and 21 in the OM-only cohort. We found no obvious effect of GER on the nasopharyngeal and middle ear microbiota between the two groups of children. However, our results highlight the need to assess the true role of Alloiococcus spp. and Turicella spp. in children presenting with a high prevalence of recurrent AOM and chronic OME.

Next-Generation Sequencing Combined with Specific PCR Assays To Determine the Bacterial 16S rRNA Gene Profiles of Middle Ear Fluid Collected from Children with Acute Otitis Media

Although S. pneumoniae, H. influenzae, and M. catarrhalis have been long established as the most important pathogens in acute otitis media using culture and specific PCR assays, the knowledge of their mutual quantitative relations and possible roles of other bacteria is incomplete. The advent of unbiased bacteriome 16S rRNA gene profiling has allowed the detection of nearly all bacteria present in the sample, and it helps in depicting their mutual quantitative ratios. Due to the difficulties in performing mass sequencing in low-volume samples, only a few bacteriome-profiling studies of otitis media have been published, all limited to cases of chronic otitis media. Here, we present a study on samples obtained from young children with acute otitis media, successfully using a strategy of nested PCR coupled with mass sequencing, and demonstrate that the method can confer quantitative information hardly obtainable by other methods.

The aim of the study was to analyze the bacteriome of acute otitis media with a novel modification of next-generation sequencing techniques. Outpatient children with acute otitis media were enrolled in the study, and middle ear fluids were collected during 90 episodes from 79 subjects aged 5 to 42 months (median age, 19 months). The bacteriome profiles of middle ear fluid samples were determined by a nested-PCR amplification of the 16S rRNA gene (V4 region), followed by mass sequencing. The profiling results were compared to the results of specific PCR assays targeting selected prevalent pathogens. Bacteriome profiling using nested amplification of low-volume samples was aided by a bioinformatic subtraction of signal contaminants from the recombinant polymerase, achieving a sensitivity slightly lower than that of specific PCR detection. Streptococcus pneumoniae was detected in 28 (31%) samples, Haemophilus influenzae in 24 (27%), Moraxella catarrhalis in 18 (20%), Staphylococcus spp. in 21 (23%), Turicella otitidis in 5 (5.6%), Alloiococcus otitidis in 3 (3.3%), and other bacteria in 14 (16%) using bacteriome profiling. S. pneumoniae was the dominant pathogen in 14 (16%) samples, H. influenzae in 15 (17%), M. catarrhalis in 5 (5.6%), T. otitidis in 2, and Staphylococcus auricularis in 2. Weaker signals of Prevotella melaninogenica, Veillonella dispar, and Veillonella montpellierensis were noted in several samples. Fourteen samples (16%) were not explainable by bacterial pathogens; novel causative agents were not detected. In conclusion, unbiased bacteriome profiling helped in depicting the true mutual quantitative ratios of ear bacteria, but at present, its complicated protocol impedes its routine clinical use.

IMPORTANCE Although S. pneumoniae, H. influenzae, and M. catarrhalis have been long established as the most important pathogens in acute otitis media using culture and specific PCR assays, the knowledge of their mutual quantitative relations and possible roles of other bacteria is incomplete. The advent of unbiased bacteriome 16S rRNA gene profiling has allowed the detection of nearly all bacteria present in the sample, and it helps in depicting their mutual quantitative ratios. Due to the difficulties in performing mass sequencing in low-volume samples, only a few bacteriome-profiling studies of otitis media have been published, all limited to cases of chronic otitis media. Here, we present a study on samples obtained from young children with acute otitis media, successfully using a strategy of nested PCR coupled with mass sequencing, and demonstrate that the method can confer quantitative information hardly obtainable by other methods.

Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae

Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds.

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that mainly causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. However, the underlying mechanisms involved in this process are poorly elucidated. In this study, we used a transposon mutant library to identify bacterial genes involved in biofilm formation. The growth and biofilm formation of 4,172 transposon mutants were determined, and the involvement of the identified genes in biofilm formation was validated in in vitro experiments. Here, we present experimental data showing that increased bacterial lysis, through interference with peptidoglycan synthesis, results in elevated levels of extracellular DNA, which increased biofilm formation. Interestingly, similar results were obtained with subinhibitory concentrations of β-lactam antibiotics, known to interfere with peptidoglycan synthesis, but such an effect does not appear with other classes of antibiotics. These results indicate that treatment with β-lactam antibiotics, especially for β-lactam-resistant NTHi isolates, might increase resistance to antibiotics by increasing biofilm formation.

IMPORTANCE Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds.

Vitamin D Levels in Children with Adenotonsillar Hypertrophy and Otitis Media with Effusion

INTRODUCTION

Vitamin D has been suggested to play a considerable role in the function of the immune system in various infectious, inflammatory, and autoimmune conditions. Otitis media with effusion (OME), defined as the presence of non-purulent fluid within the middle ear without signs or symptoms of suppurative otitis media, has a number of inflammatory predisposing factors. This study was designed to explore the association between vitamin D deficiency and OME.

MATERIALS AND METHODS

In this cross-sectional study, 74 children aged 2-7 years with an obstructive indication for adenotonsillectomy were included. Patients were divided into two groups based on the need for ventilation tube insertion for OME. Thirty-two children were enrolled in the OME group and 42 in the control group. The mean vitamin D level was compared between the two groups.

RESULTS

Mean vitamin D concentration in all patients was 11.96±5.85 ng/ml (9.79±4.36 ng/ml in the OME group and 13.61±6.33 ng/ml in the control group; P=0.003). There was also a significant difference in levels of vitamin D in patients referred in winter (9.0±2.94 ng/ml) compared with the summer (19.85±4.21 ng/ml; P=0.001). Data analyzed based on the season in which the patients were referred showed no significant difference between the OME and the control group.

CONCLUSION

Although our results showed lower serum levels of vitamin D in OME patients, the difference was not significant when seasons were taken into consideration. Therefore, the season is an important confounding factor in any research related to vitamin D due to the effect of sun-induced vitamin D.

Antimicrobial activity of antisense peptide-peptide nucleic acid conjugates against non-typeable Haemophilus influenzae in planktonic and biofilm forms

BACKGROUND

Antisense peptide nucleic acids (PNAs) are synthetic polymers that mimic DNA/RNA and inhibit bacterial gene expression in a sequence-specific manner.

METHODS

To assess activity against non-typeable Haemophilus influenzae (NTHi), we designed six PNA-peptides that target acpP, encoding an acyl carrier protein. MICs and minimum biofilm eradication concentrations (MBECs) were determined. Resistant strains were selected by serial passages on media with a sub-MIC concentration of acpP-PNA.

RESULTS

The MICs of six acpP-PNA-peptides were 2.9-11 mg/L (0.63-2.5 μmol/L) for 20 clinical isolates, indicating susceptibility of planktonic NTHi. By contrast, MBECs were up to 179 mg/L (40 μmol/L). Compared with one original PNA-peptide (acpP-PNA1-3'N), an optimized PNA-peptide (acpP-PNA14-5'L) differs in PNA sequence and has a 5' membrane-penetrating peptide with a linker between the PNA and peptide. The optimized PNA-peptide had an MBEC ranging from 11 to 23 mg/L (2.5-5 μmol/L), indicating susceptibility. A resistant strain that was selected by the original acpP-PNA1-3'N had an SNP that introduced a stop codon in NTHI0044, which is predicted to encode an ATP-binding protein of a conserved ABC transporter. Deletion of NTHI0044 caused resistance to the original acpP-PNA1-3'N, but showed no effect on susceptibility to the optimized acpP-PNA14-5'L. The WT strain remained susceptible to the optimized PNA-peptide after 30 serial passages on media containing the optimized PNA-peptide.

CONCLUSIONS

A PNA-peptide that targets acpP, has a 5' membrane-penetrating peptide and has a linker shows excellent activity against planktonic and biofilm NTHi and is associated with a low risk for induction of resistance.

Prevention of early episodes of otitis media by pneumococcal vaccines might reduce progression to complex disease

Otitis media is a common childhood infection of the middle ear and a major cause of morbidity. This multifactorial disease manifests as a spectrum of clinical syndromes from uncomplicated acute otitis media to more complex recurrent and chronic cases (frequently polymicrobial), with the major pathogens involved being Streptococcus pneumoniae and non-typeable Haemophilus influenzae. Pneumococcal conjugate vaccines (PCVs) target only a few serotypes that cause otitis media; however, results from studies suggest that existing PCVs can prevent early episodes of disease associated with vaccine serotypes, resulting in a reduction of subsequent complex cases caused by non-vaccine serotypes and other otopathogens, which contribute considerably to the disease burden. In this Review, we discuss the role of pneumococcus in the disease continuum and assess clinical evidence showing the effect of prevention of early episodes on the complex interplay between bacterial species implicated in otitis media.

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.

Colonization, safety, and tolerability study of the Streptococcus salivarius 24SMBc nasal spray for its application in upper respiratory tract infections

Streptococcus salivarius, a non-pathogenic species and the predominant colonizer of the oral microbiota, finds a wide application in the prevention of upper respiratory tract infections, also reducing the frequency of their main pathogens. In this pilot study, the primary objective was to evaluate the safety and tolerability of a nasal spray, S. salivarius 24SMBc, as a medical device in a clinical study involving 20 healthy adult subjects. The secondary aim was to determine the ability of colonization assessed by molecular fingerprinting. Twenty healthy adult subjects, aged between 30 and 54 years, without a medical history of recurrent otitis media, were enrolled. All patient characteristics fulfilled the inclusion criteria. All subjects were treated daily for 3 days with the nasal spray containing S. salivarius 24SMBc at a concentration of 5 × 10(9) colony-forming units (CFU)/ml. The persistence of S. salivarius in the nasopharynx was investigated by the antagonism test and random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). The tolerability and safety were clinically assessed by clinical examinations during treatment. Our results demonstrate the capability of S. salivarius 24SMBc to colonize the rhinopharynx tissues in 95% of subjects and persist in 55% of them after 6 days from the last dose of the formulation, maintaining a concentration of 10(5) CFU/ml. The treatment was well tolerated by all healthy patients and no adverse effects were found. The topical application of streptococcal probiotics is a relatively undeveloped field but is becoming an attractive approach for both prevention and therapy, especially for pediatric age patients. S. salivarius 24SMBc possess characteristics making this strain suitable for use in bacteriotherapy.

What is behind the ear drum? The microbiology of otitis media and the nasopharyngeal flora in children in the era of pneumococcal vaccination

AIM

This study aims to describe the microbiology of middle ear fluid (MEF) in a cohort of children vaccinated with Streptococcus pneumoniae conjugate vaccine (PCV7) having ventilation tube insertion. Nasopharyngeal (NP) carriage of otopathogens in these children is compared with children without history of otitis media.

METHODS

Between May and November 2011, MEF and NP samples from 325 children aged <3 years were collected in three major centres in New Zealand at the time of ventilation tube insertion. An age-matched non-otitis-prone comparison group of 137 children had NP samples taken. A questionnaire was completed by both groups.

RESULTS

Immunisation coverage with at least one dose of PCV7 was 97%. Haemophilus influenzae was cultured in 19.4% of MEF and was polymerase chain reaction (PCR) positive in 43.4%. S. pneumoniae and Moraxella catarrhalis were cultured in <10% of MEF samples but were PCR positive for 23.1% and 38.7%, respectively. H. influenzae was the most common organism isolated from NP samples (60%) in the grommet group, while M. catarrhalis (56%) was the most common in the non-otitis prone group. S. pneumoniae was more commonly found in the nasopharynx of children with ear disease (41% vs. 29%). 19F was the most prominent S. pneumoniae serotype in NP samples of both groups, but no serotype dominated in MEF. Ninety-five per cent of H. influenzae isolates were confirmed to be non-typeable H. influenzae.

CONCLUSION

In this cohort of children with established ear disease requiring surgical intervention, non-typeable H. influenzae is the dominant pathogen in both the nasopharynx and MEF.

Binding of human factor H to outer membrane protein P5 of non-typeable Haemophilus influenzae contributes to complement resistance

Non-typeable Haemophilus influenzae is an opportunistic pathogen of the human upper respiratory tract and is often found to cause inflammatory diseases that include sinusitis, otitis media and exacerbations of chronic obstructive pulmonary disease. To persist in the inflammatory milieu during infection, non-typeable H. influenzae must resist the antimicrobial activity of the human complement system. Here, we used Tn-seq to identify genes important for resistance to complement-mediated killing. This screen identified outer membrane protein P5 in evasion of the alternative pathway of complement activation. Outer membrane protein P5 was shown to bind human complement regulatory protein factor H directly, thereby, preventing complement factor C3 deposition on the surface of the bacterium. Furthermore, we show that amino acid variation within surface-exposed regions within outer membrane P5 affected the level of factor H binding between individual strains.

Shielding of a lipooligosaccharide IgM epitope allows evasion of neutrophil-mediated killing of an invasive strain of nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae is a frequent cause of noninvasive mucosal inflammatory diseases but may also cause invasive diseases, such as sepsis and meningitis, especially in children and the elderly. Infection by nontypeable Haemophilus influenzae is characterized by recruitment of neutrophilic granulocytes. Despite the presence of a large number of neutrophils, infections with nontypeable Haemophilus influenzae are often not cleared effectively by the antimicrobial activity of these immune cells. Herein, we examined how nontypeable Haemophilus influenzae evades neutrophil-mediated killing. Transposon sequencing (Tn-seq) was used on an isolate resistant to neutrophil-mediated killing to identify genes required for its survival in the presence of human neutrophils and serum, which provided a source of complement and antibodies. Results show that nontypeable Haemophilus influenzae prevents complement-dependent neutrophil-mediated killing by expression of surface galactose-containing oligosaccharide structures. These outer-core structures block recognition of an inner-core lipooligosaccharide epitope containing glucose attached to heptose HepIII-β1,2-Glc by replacement with galactose attached to HepIII or through shielding HepIII-β1,2-Glc by phase-variable attachment of oligosaccharide chain extensions. When the HepIII-β1,2-Glc-containing epitope is expressed and exposed, nontypeable Haemophilus influenzae is opsonized by naturally acquired IgM generally present in human serum and subsequently phagocytosed and killed by human neutrophils. Clinical nontypeable Haemophilus influenzae isolates containing galactose attached to HepIII that are not recognized by this IgM are more often found to cause invasive infections.

Neutrophils are white blood cells that specialize in killing pathogens and are recruited to sites of inflammation. However, despite the presence of large numbers of neutrophils in the middle ear cavity and lungs of patients with otitis media or chronic obstructive pulmonary disease, respectively, the bacterium nontypeable Haemophilus influenzae is often not effectively cleared from these locations by these immune cells. In order to understand how nontypeable Haemophilus influenzae is able to cause inflammatory diseases in the presence of neutrophils, we determined the mechanism that underlies resistance to neutrophil-mediated killing. We have shown that nontypeable Haemophilus influenzae prevents binding of antibodies of the IgM subtype through changes in their surface lipooligosaccharide structure, thereby preventing complement activation and clearance by human neutrophils.

Substrate binding protein SBP2 of a putative ABC transporter as a novel vaccine antigen of Moraxella catarrhalis

Moraxella catarrhalis is a common respiratory tract pathogen that causes otitis media in children and infections in adults with chronic obstructive pulmonary disease. Since the introduction of the pneumococcal conjugate vaccines with/without protein D of nontypeable Haemophilus influenzae, M. catarrhalis has become a high-priority pathogen in otitis media. For the development of antibacterial vaccines and therapies, substrate binding proteins of ATP-binding cassette transporters are important targets. In this study, we identified and characterized a substrate binding protein, SBP2, of M. catarrhalis. Among 30 clinical isolates tested, the sbp2 gene sequence was highly conserved. In 2 different analyses (whole-cell enzyme-linked immunosorbent assay and flow cytometry), polyclonal antibodies raised to recombinant SBP2 demonstrated that SBP2 expresses epitopes on the bacterial surface of the wild type but not the sbp2 mutant. Mice immunized with recombinant SBP2 showed significantly enhanced clearance of M. catarrhalis from the lung compared to that in the control group at both 25-μg and 50-μg doses (P < 0.001). We conclude that SBP2 is a novel, attractive candidate as a vaccine antigen against M. catarrhalis.

Incorporation of phosphorylcholine into the lipooligosaccharide of nontypeable Haemophilus influenzae does not correlate with the level of biofilm formation in vitro

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. The objective of this report was to determine the relationship between the presence of phosphorylcholine in the lipooligosaccharide of NTHi and the level of biofilm formation. The study was performed on 111 NTHi clinical isolates collected from oropharyngeal samples of healthy children, middle ear fluid of children with otitis media, and sputum samples of patients with chronic obstructive pulmonary disease or community-acquired pneumonia. NTHi clinical isolates presented a large variation in the level of biofilm formation in a static assay and phosphorylcholine content. Isolates collected from the oropharynx and middle ear fluid of children tended to have more phosphorylcholine and made denser biofilms than isolates collected from sputum samples of patients with chronic obstructive pulmonary disease or community-acquired pneumonia. No correlation was observed between biofilm formation and the presence of phosphorylcholine in the lipooligosaccharide for either planktonic or biofilm growth. This lack of correlation was confirmed by abrogating phosphorylcholine incorporation into lipooligosaccharide through licA gene deletion, which had strain-specific effects on biofilm formation. Altogether, we present strong evidence to conclude that there is no correlation between biofilm formation in a static assay and the presence of phosphorylcholine in lipooligosaccharide in a large collection of clinical NTHi isolates collected from different groups of patients.

Impact of immunization with Protein F on pulmonary clearance of nontypeable Haemophilus influenzae

Nontypeable Haemophilus influenzae (NTHi) is one of the main aetiologies of childhood bacterial infections as well as exacerbations in COPD patients. Currently, no licensed NTHi vaccine exists. In the present study, we evaluated the potential of the conserved and ubiquitous surface protein Haemophilus Protein F (PF) as a vaccine candidate. Our results show that incubation of NTHi with anti-PF antibodies significantly increased the opsonophygocytosis of human promyelocytic leukemia cell line-derived granulocytes, leading to efficient killing of the bacteria (P≤0.05). The presence of anti-PF IgG titers in healthy adults (n=60) was investigated, and we found that 26% of healthy blood donors carried antibodies with the main antigenic epitope being PF(23-48). Finally, mice immunized with PF(23-48) attained a significantly increased capacity to clear NTHi as compared to a control group immunized with a peptide derived from Moraxella catarrhalis β-lactamase (P≤0.05). Taken together, our results indicate that PF is a potential NTHi-vaccine candidate.

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.

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.

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.

Respiratory infections in Eñepa Amerindians are related to malnutrition and Streptococcus pneumoniae carriage

OBJECTIVES

High acute respiratory tract infection (ARTI) rates are observed in indigenous populations. We assessed the role of viral infections and nasopharyngeal bacterial carriage in ARTIs in Eñepa Amerindians from Venezuela.

METHODS

In 40 children aged 0-10 years with ARTIs, healthy nearest-age sibling controls and their mothers the presence of Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydophila pneumoniae/psittachi and 15 respiratory viruses was investigated.

RESULTS

S. pneumoniae was the most frequently detected pathogen, with carriage rates of 75% and 38% in children and mothers respectively. In children, S. pneumoniae carriage was associated with ARTI risk in multivariate analysis (OR 14.1, 95% CI 1.4-137.7). Viral infections were not associated with ARTI risk. S. pneumoniae carriage was common in children of all ages while viral co-infections were more frequently present in children under 4 years compared to older children (46% vs. 17%, p < 0.01). An increase of one unit height-for-age Z score (i.e. improved chronic nutritional status) was associated with decreased odds of S. pneumoniae colonization in multivariate analysis (OR 0.66, 95% CI 0.44-0.99).

CONCLUSIONS

In Eñepa children high S. pneumoniae carriage rates associated with a poor nutritional status contribute to the development of ARTIs.