Management of otitis media: 2000 and beyond

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.

Otitis media with effusion in Lebanese children: prevalence and pathogen susceptibility

OBJECTIVE

To determine the prevalence and resistance profile of bacterial pathogens present in the middle ear of children with otitis media with effusion, and to report beta-lactamase-negative, ampicillin-resistant bacteria for the first time in Lebanese children.

METHOD

We included 62 patients younger than 12 year (107 ears), who underwent myringotomy with tympanostomy tube placement for persistent otitis media with effusion. Bacteria were identified by Gram staining and biochemical tests, and antibiotic sensitivities tested by the disc diffusion method and via minimum inhibitory concentration (E-test).

RESULTS

The commonest pathogen was Haemophilus influenzae (62 per cent), followed by Streptococcus pneumoniae (26 per cent). The H influenzae resistance profile was highest for amoxicillin (81.0 per cent) and lowest for cefotaxime (19.0 per cent). There was a high risk of developing H influenzae antibiotic resistance among children with a history of smoking exposure (p = 0.001), recurrent upper respiratory tract infection (p = 0.001) or previous antibiotic treatment (p = 0.005). Fifty-two per cent of H influenzae colonies were found to be beta-lactamase-negative and ampicillin-resistant.

CONCLUSION

In these children with persistent otitis media with effusion, H influenzae was the most prevalent bacteria. It showed a high incidence of resistance to the antibiotics most commonly prescribed to treat acute otitis media.

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

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

Strain-specific virulence phenotypes of Streptococcus pneumoniae assessed using the Chinchilla laniger model of otitis media

Background

Streptococcus pneumoniae [Sp] infection is associated with local and systemic disease. Our current understanding of the differential contributions of genetic strain variation, serotype, and host response to disease phenotype is incomplete. Using the chinchilla model of otitis media [OM] we investigated the disease phenotype generated by the laboratory strain TIGR4 and each of thirteen clinical strains (BS68-75, BS290, BS291, BS293, BS436 and BS437); eleven of the thirteen strains have been genomically sequenced.

Methodology/Principal Findings

For each strain 100 colony forming units were injected bilaterally into the tympanic bullae of 6 young adult chinchillas under general anesthesia. All animals were examined daily for local and systemic disease by a blinded observer. Pneumatic otoscopy was used to evaluate local disease, and behavioral assessments served as the measure of systemic disease. Virulence scoring was performed using a 4-point scale to assess four clinical parameters [severity and rapidity of local disease onset; and severity and rapidity of systemic disease onset] during a 10-day evaluation period. Highly significant variation was observed among the strains in their ability to cause disease and moribundity.

Conclusions/Significance

As expected, there was a significant correlation between the rapidity of systemic disease onset and severity of systemic disease; however, there was little correlation between the severity of otoscopic changes and severity of systemic disease. Importantly, it was observed that different strains of the same serotype produced as broad an array of disease phenotypes as did strains of different serotypes. We attribute these phenotypic differences among the strains to the high degree of genomic plasticity that we have previously documented.

Expression of a peroxiredoxin-glutaredoxin by Haemophilus influenzae in biofilms and during human respiratory tract infection

Evidence is mounting that nontypeable Haemophilus influenzae grows as a biofilm in the middle ear of children with otitis media and the airways of adults with chronic obstructive pulmonary disease. To begin to assess antigens expressed by H. influenzae in biofilms, cell envelopes of bacteria grown as a biofilm were compared to those grown planktonically. A approximately 30kDa peroxiredoxin-glutaredoxin was present in greater abundance during growth in biofilms. Mutants deficient in expression of peroxiredoxin-glutaredoxin were constructed by homologous recombination in four clinical isolates. The mutants showed a 25-50% reduction in biofilm formation compared to the corresponding parent strains. To study in vivo expression of peroxiredoxin-glutaredoxin during human respiratory tract infection, paired pre- and post-exacerbation serum from adults with chronic obstructive pulmonary disease and H. influenzae in sputum were assayed using an enzyme-linked immunosorbent assay and purified recombinant peroxiredoxin-glutaredoxin. Eight from 18 (44.4%) paired serum samples showed a significant increase in antibody to peroxiredoxin-glutaredoxin from pre- to post-infection. These results indicate that (1) peroxiredoxin-glutaredoxin is present in greater abundance in H. influenzae biofilms compared to planktonically grown bacteria; (2) peroxiredoxin-glutaredoxin is involved in biofilm formation by H. influenzae and the degree of involvement varies among strains; and (3) peroxiredoxin-glutaredoxin is expressed by H. influenzae during infection of the human respiratory tract and is recognized by the human immune system.

Pneumococcal conjugate vaccines for preventing vaccine-type invasive pneumococcal disease and pneumonia with consolidation on x-ray in children under two years of age

BACKGROUND

Pneumonia, most commonly caused by Streptococcus pneumoniae (Pnc), is a major cause of morbidity and mortality among young children especially in developing countries. Recently, the prevalence of antibiotic-resistant Pnc has increased worldwide such that the effectiveness of preventive strategies, like the new pneumococcal conjugate vaccines (PCV) on rates of invasive pneumococcal disease (IPD) and pneumonia, needs to be evaluated.

OBJECTIVES

To determine the efficacy of PCV in reducing the incidence of IPD due to vaccine serotypes (VT) and x-ray confirmed pneumonia with consolidation of unspecified etiology in children who received PCV before 12 months of age.

SEARCH STRATEGY

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2004), MEDLINE (1990 to March 2004) and EMBASE (1990 to December 2003). Reference list of articles, and books of abstracts of relevant symposia, were hand searched. Researchers in the field were also contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing PCV with placebo, or another vaccine, among children below two years with IPD and clinical/radiographic pneumonia as outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently identified eligible studies, assessed trial quality, and extracted data. Differences were resolved by discussion. The inverse variance method was used to pool effect sizes.

MAIN RESULTS

We identified four trials assessing the efficacy of PCV in reducing the incidence of IPD, two on x-ray confirmed pneumonia as outcome, and one on clinical pneumonia, with or without x-ray confirmation. Results from pooling HIV-1 negative children from the South African study with the other studies were as follows: the pooled vaccine efficacy (VE) for vaccine-type IPD was 88% (95% confidence interval (CI) 73% to 94%; fixed effect and random effects models), the effect measure was statistically significant (p <0.00001) and there was no heterogeneity (p = 0.77I2 0%); the pooled VE for all-serotype IPD was 66% (95% CI 46% to 79%; fixed effect model), the effect measure was statistically significant (p <0.00001) and there was no statistical heterogeneity (p = 0.09, I2 51%); the pooled VE for x-ray confirmed pneumonia was 22% (95% CI 11% to 31%; both fixed effect and random effects models) and there was no statistical heterogeneity (p = 0.80, I2 0%). Analyses that included all the children in the South African study (HIV-1 negative and HIV-1 positive children) and pooled with data from the other studies gave very similar results.

REVIEWERS' CONCLUSIONS

PCV is effective in reducing the incidence of IPD from all serotypes but exerts a greater effect in reducing VT IPD. Although PCV is also effective in reducing the incidence of x-ray confirmed pneumonia, there are still uncertainties about the definition of this outcome. Additional randomised controlled trials are currently in progress.

The effect of montelukast sodium on the duration of effusion of otitis media

This study tests the hypothesis that montelukast sodium, a selective leukotriene receptor antagonist, will decrease the duration of the effusion of otitis media. Tympanometry and spectral gradient acoustic reflectometry were used to confirm the effusion of otitis media in patients between 2 and 12 years of age. Patients were treated with amoxicillin for 10 days and montelukast sodium or placebo for 30 days in a random, double-blind manner. Sixty patients completed the study: 31 received placebo and 29 received montelukast sodium. At a 4-week follow-up visit, 5 ears (16%) were free of effusion in the placebo group and 17 (58%) in the montelukast sodium group. The difference was significant. The efficacy of montelukast sodium in clearing the effusion was 49%.

Hearing and vision screening program for school-aged children

BACKGROUND

Hearing and vision screening programs for school-aged children are common, yet little is known about their impact.

OBJECTIVE

To evaluate Michigan's screening program, in which local health department (LHD) staff screen school-aged children using standardized protocols.

METHODS

This project was completed in three phases: interviews with officials and screening technicians from ten LHDs, audit of LHD records regarding outcomes of screening during the 2000-2001 school year, and telephone interviews with randomly selected parents of children with an abnormal screen.

RESULTS

Variations in LHD program implementation pertained to methods for tracking outcomes, screening of older children, parental notification of screening results, and availability of follow-up hearing clinics. According to LHD records, documentation of follow-up examination after an abnormal screen was low (hearing 27%, vision 25%). In contrast, most parents reported follow-up (74% hearing, 76% vision), and many reported that this resulted in treatment (50% hearing, 74% vision). In logistic regression modeling, the odds of follow-up after hearing or vision screening according to parents was not associated with income, health insurance status, or race/ethnicity. For hearing screening, the odds of follow-up decreased with school grade (p <0.001); however, the proportion who received treatment did not vary by grade. For vision screening, follow-up did not vary by grade, but the proportion who received treatment increased with grade (p =0.05).

CONCLUSIONS

According to parent reports, most children had follow-up after an abnormal screen, and the majority of these children received treatment. Screening school-aged children for sensory impairment appears to be an important public health function.

Pharmacokinetics and efficacy of linezolid in a gerbil model of Streptococcus pneumoniae-induced acute otitis media

The oxazolidinone linezolid represents a new antibacterial class of potential benefit in managing multidrug-resistant gram-positive infections, including those caused by Streptococcus pneumoniae. In a gerbil model of acute otitis media (AOM) induced by either penicillin-resistant S. pneumoniae (PRSP; amoxicillin MIC = 8 micro g/ml, linezolid MIC = 1 micro g/ml) or penicillin-susceptible S. pneumoniae (PSSP; amoxicillin MIC = 0.015 micro g/ml, linezolid MIC = 1 micro g/ml), we explored the plasma and ear fluid levels of linezolid required to demonstrate efficacy. Threshold pathogen doses required to induce bilateral AOM (1,500 CFU/ear with PRSP; 30 CFU/ear with PSSP) were administered to gerbils by intrabullar injection on day 0. At peak infection ( approximately 10(6) to 10(7) CFU/ear flush; day 2 for PRSP-AOM and day 3 for PSSP-AOM), twice-a-day oral doses of linezolid, amoxicillin, or vehicle were administered over 4.5 days prior to collection and assay of middle ear effluents for S. pneumoniae content. Linezolid doses of >/=10 mg/kg of body weight induced significant cure rates of >/=72% versus both PRSP and PSSP infections, whereas amoxicillin at </=100 mg/kg was consistently effective only versus PSSP-AOM. Plasma and ear fluid levels of linezolid necessary to elicit pneumococcal eradication from the middle ear were measured by high-performance liquid chromatography-tandem mass spectrometry and found to be similar both within and between each infection protocol. The plasma-ear fluid pharmacodynamic profile associated with linezolid efficacy was a T>MIC of >/=42%, a C(max)/MIC ratio of >/=3.1, and a (24-h area under the curve)/MIC ratio of >/=30 h. Application of this model will be useful in defining preclinical pharmacodynamic relationships of novel antibiotics necessary to cure S. pneumoniae-induced AOM.

[Survey of the judicious use of antibiotics in primary care]

OBJECTIVE

To identify pediatricians' antibiotic prescribing habits in acute otitis media and tonsillopharyngitis and to determine the interaction between parents and pediatricians concerning antibiotic use in the Autonomous Community of Valencia (Spain).

METHOD

Four hundred members of the Valencian Society of Pediatrics were randomly selected. A semi-structured questionnaire with non-excluding answers was sent by mail and, when responses were not obtained, a second one was sent. The confidentiality of the information was guaranteed.

RESULTS

Of 400 questionnaires sent, 143 (35.8 %) were completed; 88.1 % were completed by pediatricians and 51.1 % by primary care workers. A total of 48.3 % of pediatricians used antibiotics in all cases of acute otitis media and 94.5 % prescribed them when fever and otalgia persisted for more than 48 hours. Amoxicillin-clavulanate was the most frequently prescribed antibiotic (63.6 %). Less than 10 % of pediatricians prescribed antibiotics as empirical treatment in tonsillopharyngitis; amoxicillin was the most frequently prescribed antibiotic (54.6 %). Indications for antibiotic treatment were fever, odynophagia and adenomegaly (69.5 %) and tonsillar exudate (62.5 %). Inappropriate antibiotic use was mainly due to excess workload. Providing health education to parents could be the best way of reducing inappropriate use.

CONCLUSIONS

Antibiotic use is frequent in the treatment of acute otitis media. Amoxicillin-clavulanate and amoxicillin were the most frequently prescribed antibiotics in tonsillopharyngitis. Providing health education to parents and reducing pediatricians' workload would decrease inappropriate antibiotic use.

Combating bacterial resistance in otorhinolaryngology

Bacterial resistance appears to be an ever-increasing problem and is threatening to spiral out of control. The scare caused by the rapid spread of methicillin-resistant Staphylococcus aureus among hospitals in the UK is the most recent. Otorhinolaryngology is deeply involved in this problem, as one of the reasons often cited for increasing bacterial resistance is the use of antibiotics in suspected bacterial infections in ear, nose and throat by primary care physicians. This speciality is also involved in the development of guidelines for antimicrobial use by primary and secondary care. This review attempts to discuss the reason for the development of antimicrobial resistance especially in relation to otorhinolaryngology, what can be done to contain this menace and the surveillance system developed to monitor the trend in the development of bacterial resistance.

Medical and surgical management of otitis media in children

OM, though frequent and seemingly simple to evaluate and manage, remains a treatment challenge. Increasingly sophisticated clinical trials assessing OM medical treatment efficacy and outcome have demonstrated that many treatment regimens that were commonly used a decade ago are no longer recommended. Surgical therapy for OM, though remaining the same, has come under intense scrutiny from several angles but still plays a central role for this disease. Given the multiple facets of OM, its frequency, and its potential to cause short- and long-term morbidity in children, the next decade is sure to bring further treatment innovations.

Biofilm formation by nontypeable Haemophilus influenzae: strain variability, outer membrane antigen expression and role of pili

BACKGROUND

Nontypeable Haemophilus influenzae is an important cause of otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Several lines of evidence suggest that the bacterium grows as a biofilm in the human respiratory tract.

RESULTS

Fifteen clinical isolates from middle ear fluid of children with otitis media and 15 isolates from sputum of adults with COPD were studied in an in vitro assay of biofilm formation. Striking variability among isolates was observed in their ability to form biofilms. Analysis of cell envelopes revealed minimal differences in banding patterns in polyacrylamide gels, alteration of expression of an epitope on lipooligosaccharide, and preservation of expression of selected epitopes on outer membrane proteins P2, P5 and P6 in biofilms compared to planktonically grown cells. A pilus-deficient variant showed a marked impairment in biofilm formation compared to its isogenic parent.

CONCLUSIONS

Nontypeable H. influenzae forms biofilms in vitro. Clinical isolates show substantial variability in their ability to grow as biofilms. Three major outer membrane proteins (P2, P5 and P6) are expressed during growth as a biofilm. Expression of lipooligosaccharide is altered during growth as a biofilm compared to planktonic growth. Pili are important in biofilm formation. As the role of biofilms in human infection becomes better defined, characterization of biofilms may be important in understanding the pathogenesis of infection and immune response to nontypeable H. influenzae in children with otitis media and adults with COPD.

[Mortality due to Streptococcus pneumoniae infection in children. A 5-year retrospective study in Ile-de-France]

Streptococcus pneumoniae is the leading cause of community acquired infections. We conducted a 5 years retrospective study to assessed mortality of pneumococcal infections in children in the area of Paris. Regarding the provided answers, the mortality rate is 0.3/100.000/year in the 0-15 years old children. The majority of them are toddlers. Only 30% of cases occurred in high-risk children. Meningitis was the main cause of death. Pneumococcal resistance to antibiotics did not appear as a risk factor of mortality.