Microorganisms in chronic otitis media with effusion

The bacteriome of otitis media with effusion: Does it originate from the adenoid?

OBJECTIVE

The aim of this study was to evaluate the composition and the diversity of bacteriome in middle ear effusion (MEE) and adenoid specimens of pediatric patients having otitis media with effusion (OME).

MATERIALS AND METHODS

Sample collection from children with OME followed by next generation sequencing. Seventeen adenoid and 43 middle ear effusion specimens from 25 children having OME were evaluated. Microbiome analysis was performed via Ion 16S rRNA metagenomics kit.

RESULTS

Twenty-two different bacterial species were identified from all of the samples analyzed. There were variations in the prevalence and relative abundance of the bacteriome observed between adenoid and MEE samples. MEE microbiome was significantly dominated by Alloicoccus otitis (44%), Turicella otitidis (6%), and Staphylococcus auricularis (3%). Whereas, Rothia mucilaginosa (39%), R. dentocariosa (11%), S. aureus (5%), Veillonella rogosae (2%), Granulicatella elegans (2%), Granulicatella adiacens (2%), Eikenella corrodens (1%), and Prevotella nanceiensis (1%) had significantly higher relative abundance in adenoid samples. Overall, there was no statistically significant difference in alpha diversity of MEE and adenoid samples, whereas adenoid samples constituted a cluster in the beta diversity graph.

CONCLUSION

Bacteriome of MEE is mostly dominated by A. otitis yet accompanied by other bacteria with lower relative abundances suggests that OME is likely to be a polymicrobial process. Despite similarities, significant differences in relative abundances of several predominant species between bacteriome in the MEE and adenoid put the theory that OME in children is originated from the adenoids under question.

Laser-Assisted Tympanostomy in Pediatric Patients with Serous Otitis Media

OBJECTIVES: To evaluate prognostic factors related with cure rate, in pediatric patients with serous otitis media treated with laser-assisted tympanostomy without ventilation tubes, in a single institution.

PATIENTS AND METHOD: The procedure was performed on 124 ears in 88 individuals, from 3 to 14 years old. External auditory canal anatomy, type of anesthesia, tympanic membrane and middle ear fluid characteristics, myringotomy size, and laser parameters, in relation to cure rate, were accordingly studied.

RESULTS: The overall cure rate by ear at the end of the 2-month follow-up period was 54.83%, whereas 45.17% still suffered from otitis media. Multivariate statistical analysis demonstrated that the presence of a thick tympanic membrane is significantly correlated with pure outcome in children with serous otitis media, when laser-assisted tympanostomy without ventilation tubes is performed favoring a worse cure rate ( P < 0.023). Other parameters did not statistically correlate with the outcome. A 41% parental dissatisfaction rate was noticed.

CONCLUSION: This study addresses selection bias for children with serous otitis media, candidates for laser-assisted tympanostomy. These are related to the duration of serous otitis media, the condition of middle ear mucosa, the thickness of the tympanic membrane, the type of anesthesia, and the cost of laser apparatus. There is likely to be a causal relationship between outcome and tympanic membrane appearance in children undergoing laser-assisted tympanostomy.

Ultrasound characterization of middle ear effusion

PURPOSE

To further enhance and assess the ability to characterize middle ear effusion (MEE) using non-invasive ultrasound technology.

MATERIALS AND METHODS

This is a prospective unblinded comparison study. Fifty-six children between the ages of 6 months and 17 years scheduled to undergo bilateral myringotomy with pressure equalization tube placement were enrolled. With the child anesthetized, the probe was placed into the external ear canal after sterile water was inserted. Ultrasound recordings of middle ear contents were analyzed by computer algorithm. Middle ear fluid was collected during myringotomy and analyzed for bacterial culture and viscosity.

RESULTS

Ultrasound waveforms yielded a computer algorithm interpretation of middle ear contents in 66% of ears tested. When a result was obtained, the sensitivity and specificity for successfully characterizing middle ear fluid content as either void of fluid, thick fluid (mucoid), or thin fluid (serous or purulent) were at least 94%. Mucoid effusions had higher measured viscosity values (P=.002). Viscosity measures were compared to culture result, and those with low viscosity (thin consistency) had a higher likelihood of having a positive culture (P=.048).

CONCLUSION

The device sensitivity and specificity for fluid detection were 94% or greater among interpretable waveforms (66% of those tested). Although this technology provides important information of the middle ear effusion presence and characteristic, further technological improvements are needed.

IgA and Differentiation-associated Transcription Factors in Chronic Otitis Media with Effusion

Objectives

Inadequate antibody responses to pathogens may lead to the recurrence of otitis media with effusion (OME). Although B-cell production by antibodies is controlled by transcription factors, the status of these factors has not been assessed in patients with OME.

Methods

Expression of immunoglobulin was measured by enzyme-linked immunosorbent assay. Expression of transcription factors Bcl-6, Blimp-1, Pax-5, and XBP-1 was assessed by RT-PCR in the middle-ear fluid of 29 children with >4 OME episodes in 12 months or >3 episodes in 6 months (the OME-prone group) and in 32 children with <3 OME episodes in 12 months (OME group). The relationship between recurrence of OME and expression levels of immunoglobulins and transcription factors in middle-ear fluid was determined.

Results

The concentration of IgA in middle-ear fluid was significantly lower in the OME-prone than in the OME group, as was the expression of mRNA encoding the transcription factors Blimp-1 and XBP-1 (P<0.05 each). Expression of mRNA encoding the transcription factors Bcl-6 and Pax-5 was more intense in the OME-prone than in the OME group, but these differences were not significant (P>0.05).

Conclusion

Lower concentrations of IgA, Blimp-1 and XBP-1 in middle ear fluid of patients with OME may be related to OME recurrence and chronicity.

Experimental evidence suggestive of early intervention in mucoid otitis media

CONCLUSIONS

Mucoid effusion can undergo a process of organization related to the inflammatory process and hypoventilation; organized effusion in the presence of epithelial breaks is a potential source for formation of granulation tissue and cholesterol granuloma within 3 months of evolution.

OBJECTIVES

The aim of this study was to investigate the evolution of mucoid otitis media and its relationship with the organized effusion within a time-span of 3 months.

MATERIALS AND METHODS

Two groups of animals were selected. In group I, 15 chinchillas had a chemically modified bovine collagen type 2 gelatin membrane placed through a mechanically induced tympanic membrane perforation, bridging the external auditory canal and the promontory. In group II, 75 cats underwent eustachian tube obstruction with soft grade silastic sponges. Experimental phases and animal sacrifices were performed under general anesthesia. After sacrifice, temporal bones were prepared, stained with hematoxylin and eosin and evaluated under light microscopy.

RESULTS

The experimental ears in both groups were observed to undergo gradual pathological changes with increasing survival times. The acute inflammatory phase turned into chronic irreversible changes, which correlated directly with the initial amount of effusion and the areas of epithelial breaks, granulation tissue, cholesterol granuloma, and epithelial migration.

The role of anaerobic bacteria in chronic suppurative otitis media in children: implications for medical therapy

This review describes the microbiology, diagnosis and medical management of chronic suppurative otitis media (CSOM) in children highlighting the role of anaerobic bacteria. In studies that employed adequate method for recovery of anaerobic bacteria polymicrobial aerobic and anaerobic flora was isolated from over half of the children with CSOM. The predominant aerobic isolates were Staphylococcus aureus and Pseudomonas aeruginosa and the most frequently isolated anaerobic organisms were Peptostreptococcus, Fusobacterium spp. and pigmented Prevotella and Porphyromonas spp. Several studies illustrated the efficacy of anti-infective agents effective against anaerobic bacteria in the treatment of CSOM. The medical therapy of CSOM should be directed at the eradication of the pathogenic aerobic and anaerobic organisms.

The role of bacterial biofilms and the pathophysiology of chronic rhinosinusitis

The earliest description of a bacterial biofilm is likely centuries old. However, only in the past few decades has a wealth of knowledge developed pertaining to this bacterial form of existence. Biofilms have been implicated mainly in chronic disease states, and the current available treatment modalities for infection have demonstrated limited efficacy against bacteria in this form. There is evidence associating bacterial biofilm formation in chronic infections of the upper airway, and therefore we examine the possible role of a bacterial biofilm in chronic rhinosinusitis while drawing parallels with recent data from other bodily regions. Lastly, directions for contemporary biofilm research are reviewed and highlighted in terms of their application to chronic rhinosinusitis.

Quantity of aerobic bacteria in the bony portion of the external auditory canal of children

OBJECTIVE

the human external auditory canal (EAC) hosts a commensal bacterial flora of mainly non-pathogens, but bacterial pathogens may also be present. The latter are important in the aetiopathogenesis of external otitis and middle ear cholesteatoma with discharge. The purpose of this study was to quantify the bacteria normally harboured in the healthy EAC and on a well-defined region of the cavum conchae (CC) of children.

METHODS

bacterial samples were collected from the CC and bony portion of the EAC of 32 children (18 boys, 14 girls; median age 5 years). Prior to sampling, the EACs were either left untreated, anaesthetized with Bonain's solution, or washed with 70% alcoholic solution. The samples were incubated at 37 degrees C and evaluated regarding bacterial species and number.

RESULTS

the predominant bacterial non-pathogens were coagulase-negative Staphylococci and coryneforms (diphtheroids) and pathogens Staphylococcus aureus and Pseudomonas aeruginosa. Total bacterial counts of the CC ranged between 2 x 10(3) and 4.6 x 10(4) CFU/cm(2) (median value 7 x 10(3); n = 14). Total bacterial counts from the bony portion of the EAC ranged between 0 and 5.7 x 10(7) CFU/EAC (median value 8 x 10(3); n = 32). Pre-treatment of the EACs with Bonain's solution containing the highly bactericidal substance phenol or with 70% alcoholic solution did not sterilize the EAC.

CONCLUSIONS

small numbers of bacterial non-pathogens (and sometimes pathogens) are found in the EAC of children. Neither phenol nor 70% alcoholic solution can inhibit or eradicate all these microorganisms.

Interactions between the middle ear and the inner ear: bacterial products

The round-window membrane (RWM) is extremely thin and is the only soft-tissue barrier between the middle ear and the inner ear. Under inflammatory conditions of the middle ear the various layers of the triple-layered RWM undergo characteristic changes parallel to the changes of the middle-ear mucosa. Several studies report that bacterial products, exo- and endotoxins, from bacteria invading the middle ear may result in profound inflammatory changes in the inner ear, followed by severe damage to the inner-ear function. The present review, in which we summarized experimental and clinical observations, on bacterial products in interactions between the middle and inner ear, focused on: 1. Bacteria and bacterial products in an inflamed middle ear that may influence inner-ear function. 2. RWM structure and RWM permeability under the influence of bacteria and bacterial products. 3. Morphological and functional inner-ear effects of bacterial infection of the middle ear, and the possible mechanisms involved. 4. Future studies to be directed in this field.

Experimental otitis media induced by coagulase negative staphylococcus and its L-forms

In a previous study, we found 15% L-forms of bacteria (predominately coagulase negative staphylococci (CNS)) in ears which gave negative cultures by conventional methods. In this study, we used an animal model to test whether CNS and its L-forms can be pathogenic and whether L-forms have a crucial role in the tendency to secretory otitis media (SOM). We inoculated the tympanic bullas of guinea pigs, in 2 groups, with CNS and its L-forms (revertant forms). We observed that both CNS and its L-forms had the capability of causing infection. However, it was milder for the L-forms than CNS. We clearly noticed that on day 30 60% of the ears inoculated with L-forms had effusion and/or retraction of the tympanic membrane. These ears were histopathologically characterized by hypertrophied pseudostratified epithelium or stratified squamous epithelial metaplasia. The ears inoculated with the original form of CNS had only 16.66% effusion. On day 60 we observed similar findings. Thus, it might be proposed that L-forms could be responsible for chronic irritation to middle ear mucosa leading to SOM.

Bacteriology of chronic suppurative otitis media

Aspiration of exudate through an open perforation was performed in 183 patients with chronic otitis media. The pus was cultured aerobically and anaerobically. Aerobes only were isolated from 71 patients (39%); 20 patients (11%) had only anaerobes; and 91 patients (50%) had both aerobes and anaerobes. Only 1 specimen had no growth. There were 259 aerobic isolates. Pseudomonas aeruginosa was recovered from 68 patients. Other aerobes commonly recovered included Staphylococcus aureus and Klebsiella pneumoniae. There were 178 anaerobic isolates. Only anaerobic gram-positive cocci were isolated in 20 instances. Sixty-three Bacteroides isolates were recovered, including 12 Bacteroides fragilis group and 21 Bacteroides melaninogenicus.

Effects of endotoxin and neutrophil lysate on experimental otitis media with effusion in cats

Middle ear effusion (MEE) from otitis media with effusion (OME) contains large amounts of chemical mediators and substances from bacteria, which may act on the mucosa itself and cause further changes in the inflamed mucosa and MEE. To clarify the effects of such substances in MEE, we instilled endotoxin (LPS) or allogeneic neutrophil lysate (NL) into the middle ear cavity of OME induced by Eustachian tube obstruction (ETO). ETO + LPS and ETO + NL groups showed retention of a large amount of MEE as a characteristic difference between ETO alone group and these groups. The instillation of LPS into the middle ear cavity of the ETO model significantly increased the number of total cells and the ratio of the concentrations of albumin to total protein in MEEs. The instillation of NL significantly increased the number of goblet cells in the middle ear. These facts indicate that the pathology of OME may change in response to various factors added to MEE. Hence, we propose that a vicious circle of self-mediated inflammation is a possible causative factor for chronic OME.

Cytological and bacteriological aspects of secretory otitis media

Bacteriological and cytological examinations were performed on 105 middle ear secretions from 66 children with middle ear effusion (MEE) of more than 3 months' duration. The secretions were searched for granulocytes and the activity of these cells was judged by their capacity for random locomotion and their ability to reduce nitroblue tetrazolium. The functional characteristics of the granulocytes were compared with the bacteriological findings on cultures from MEE. Bacteria commonly regarded as pathogens in middle ear infections (Hemophilus influenzae, Branhamella catarrhalis or Streptococcus pneumoniae) were found in 25% of the secretions. Granulocytes with activity or lacking activity, virtually dead, were found in all secretions where these bacteria were isolated. In secretions where bacteria commonly regarded as commensals, mainly staphylococci, were isolated, about two thirds of the secretions showed phagocytes with or without activity. No relation between bacterial growth and the functional state of the granulocytes was observed. In contrast, no phagocytes were found in over 60% of MEE lacking bacterial growth. These findings suggest a role for bacteria in the development and maintenance of secretory otitis media.

Endotoxin and lysosomal protease activity in acute and chronic otitis media with effusion

Endotoxin levels and lysosomal protease (collagenase, cathepsin B, and lysozyme) activity were measured in 104 middle ear effusions (MEEs) from patients with otitis media with effusion (OME). The MEE samples were classified into four groups: pediatric serous, mucoid, and acute, and adult serous. Endotoxin levels and lysosomal protease activity in MEEs were significantly different in the following order: adult less than serous less than mucoid less than acute groups, indicating that both endotoxin and lysosomal proteases are more closely related to the pathogenesis of pediatric chronic OME than to adult OME. In pediatric serous and mucoid effusions, endotoxin level had a significant correlation with activity of the lysosomal proteases. In conclusion, endotoxin enhances leukocyte infiltration into the middle ear, and lysosomal proteases released from leukocytes damage the middle ear mucosa and thereby prolong mucosal inflammation, which may be responsible for delayed recovery from acute OME.

Modern management of otitis media

In summary, infants and children who have acute otitis media should receive antimicrobial therapy. Amoxicillin is the standard of therapy for infants and children with acute otitis media, because it is safe and effective for most of the causative bacterial pathogens. Amoxicillin has also been shown to be effective for treatment of selected children with otitis media with effusion ("secretory" otitis media) and is the recommended prophylactic antimicrobial agent for prevention of frequently recurrent acute otitis media. During the past decade, however, an increasing rate of bacteria that are resistant to amoxicillin has occurred, primarily beta-lactamase-producing H. influenzae and B. catarrhalis. Because of the emergence of these bacteria, other antimicrobial agents, both old and new, have been advocated for treatment and prevention of otitis media; amoxicillin-clavulanate, cefuroxime axetil, and cefixime are the newer agents. These agents are indicated for selected infants and children; however, for most patients, amoxicillin remains a safe and relatively inexpensive effective drug. The common surgical procedures, such as myringotomy with tympanostomy tube insertion, and adenoidectomy with myringotomy with or without tympanostomy tube insertion, have now been shown to be effective for patients who have recurrent acute otitis media and chronic otitis media with effusion. The decision for or against these procedures should not only include consultation with an otolaryngologist but should also involve the parents and the child, if old enough. The risks, costs, and benefits of nonsurgical and surgical management should be discussed with all parties concerned.

Effect of formalin-fixed Hemophilus influenzae and Streptococcus pneumoniae on dye transport by the chinchilla eustachian tube

An in situ method for measuring the ability of the middle ear and eustachian tube ciliated epithelium to transport dye to the nasopharynx was used to assess the role endotoxin-containing killed bacteria have on the development of otitis media with effusion. In addition, electron microscopy was used to monitor histological changes induced by exposure to these organisms and the ability of the mucosa to recover. The results indicated that exposure to a killed gram-negative but not a gram-positive otitis media pathogen leads to early production of middle ear fluid, evidence of capillary leakage and significant slowing of mucociliary transport. The damage was, however, reversible with the epithelium returning to normal both functionally and histologically within 7 days of exposure.

Inner ear disturbances following inoculation of endotoxin into the middle ear

Inner ear function was assessed by a frequency-specific (+/-100 Hz) auditory brainstem response (ABR) technique after a single instillation of a suspension of purified E. coli lipopolysaccharide in sterile water into the round window (RW) niche in rats. Instillation of endotoxin caused a transient concentration and tonotopically dependent dysfunction of the inner ear. The largest threshold impairment occurred in the high-frequency region anatomically located close to the RW. At 31.5 kHz the threshold impairment persisted throughout the study. Morphologic damage to the inner ear was not detected at the light microscopic level when using serial sections from decalcified specimens. Our study supports the clinical hypothesis that remnants of non-viable bacteria such as endotoxins, when trapped in the middle ear, can promote middle ear effusion and dysfunction of the inner ear.

Otitis media and its relationship to allergy

The importance of infection in the etiology of otitis media and the role of eustachian tube obstruction in the pathogenesis of otitis media with effusion are well known. Recently, allergic rhinitis has been documented to induce eustachian tube obstruction. When allergic rhinitis is diagnosed in a child with recurrent or chronic middle ear disease, allergy should be considered as another risk factor for the development of otitis media with effusion.

Functional disorder of eustachian tube in experimental otitis media with effusion following inoculation of bacterial endotoxin

A 10-micrograms/mL solution of lipopolysaccharide derived from Klebsiella pneumoniae was inoculated into the middle ears of guinea pigs. The animals were killed painlessly on the first, third, or seventh day after inoculation, and the mucosal samples from the bony portion of the eustachian tube were examined for ciliary activity and epithelial morphology. On the first and third days, when middle ear effusions were present, deterioration of ciliary activity and morphologic changes in the mucociliary system were observed. On the seventh day, when middle ear effusions were absent, the ciliary activity had recovered to normal. Our data show that endotoxin extracted from K pneumoniae can produce otitis media with effusion and that dysfunction of cilia caused by endotoxin is a factor responsible for the manifestation of otitis media.

Reversibility of reduced ciliary activity on adenoids of patients with otitis media with effusion following culture

We have studied the ciliary activity of the pharyngeal epithelium on adenoids obtained from patients with recurrent otitis media with effusion to assess indirectly the ciliary activity in the Eustachian tube. In conclusion, the following has been speculated from the present study: (1) middle ear effusions depress the ciliary activity; and (2) recovery of the reduced ciliary activity can be achieved in an effusion-free environment inasmuch as the ciliated cells have not undergone organic changes. Prompt elimination of the effusion, if present, is of critical importance for the recuperation of tubotympanic drainage, because a positive therapeutic effect resulting from elimination of the effusion can only be possible in early phase of the disease, before irreversible morphological lesions have occurred.

The effect of antecedent influenza A virus infection on the adherence of Hemophilus influenzae to chinchilla tracheal epithelium

The adherence of Hemophilus influenzae (type b and nontypable) to ciliated chinchilla respiratory epithelium was investigated using a whole organ perfusion technique. Nontypable H influenzae (NTHi) were shown to be more adherent than type b to these organized and differentiated tracheal organ cultures. Bacteria were found adhering to ciliated cells. Antecedent influenza A virus infection had no effect on adherence of NTHi for at least 48 hours. However, 72 hours after exposure to the virus, infected tissues demonstrated significantly fewer adherent bacteria than did controls. To summarize, influenza A virus infection was not found to augment the initiation of NTHi adherence to ciliated respiratory epithelium in this model.

Effects of bacterial endotoxin on ciliary activity in the tubotympanum

The discovery of endotoxin in effusion of otitis media with effusion (OME) has suggested the possibility that bacterial endotoxin may be involved in the pathogenesis and development of OME. In this study, we investigated the direct effects of lipopolysaccharide (LPS), possessing the major part of endotoxin activity, on the ciliary activity in the tubotympanum. The study shows that LPS deteriorates ciliary activity in a dose-response fashion and that even low levels can, with extended exposure, cause dysfunction of cilia. It can be postulated that endotoxin in middle ear effusions aggravates the condition of mucociliary dysfunction thus leading to chronic OME.

Middle ear effusion--a theoretical neuro mechanical hypotheses

An alternative theoretical neuro-mechanical hypothesis is presented in the pathogenesis of middle ear effusion, along with a review.

The role of anaerobic bacteria in otitis media: microbiology, pathogenesis, and implications on therapy

The current knowledge of the recovery of anaerobic bacteria from cases of acute and chronic otitis media is reviewed. Although techniques for cultivation of anaerobes were used in the studies presented, the methodologies of collection, transportation, and cultivation of the specimens varied. Consequently, there were differences in the rates of recovery of these organisms and the species isolated. Anaerobes, mainly gram-positive cocci, were recovered from a quarter of ear aspirates in acute otitis media in about one third mixed with aerobic and facultative bacteria. In a study of otitis media with effusion, anaerobic bacteria were recovered in 12% of the culture-positive aspirates. The predominant anaerobes were gram-positive cocci and Bacteroides melaninogenicus. Several studies reported the recovery of anaerobes in about half of the patients with chronic otitis media and in those with cholesteatoma. The predominant anaerobes were gram-positive cocci, Bacteroides sp, and Fusobacteria sp. Many of these organisms produced beta-lactamase and might have contributed to the failure of these patients to respond to penicillins. The potential synergistic relationships between the various aerobic and anaerobic bacteria and the role of the capsule of anaerobic bacteria as a virulence factor are discussed.

Experimental otitis media with effusion induced by intratympanic lipid A instillation

Otitis media with effusion was induced in guinea pigs by intratympanic instillation of lipid A, the lipid moiety of gram-negative bacterial lipopolysaccharide from Salmonella minnesota Re595. Lipid A was chosen as an inducer because of its similar composition among various bacterial species. Animals were killed from the first to 14th day after instillation of various concentrations (0.2, 2, 20, 200 micrograms/ml) of lipid A in 0.5% triethylamine. By 3 days after instillation, all experimental animals developed serous middle ear effusion. The histologic findings included hemorrhage, mucosal edema, capillary engorgement, and migration of infiltrative cells including macrophages, polymorphonuclear neutrophils, and lymphocytes. These findings were most prominent 3 days after instillation, and the recovery of the middle ear epithelium was observed within 14 days. Repeated instillation of lipid A (2 micrograms/ml) at an interval of 14 days reinforced the local response accompanied by serous middle ear effusion. These findings indicate that lipid A can induce the inflammatory changes with middle ear effusion and that lipid A plays an important role in the pathogenesis of otitis media with effusion.

Prognosis and endotoxin contents in middle ear effusions in cases after acute otitis media

We analysed the endotoxin content of middle ear effusion (MEE) from patients after acute otitis media, by a Limulus assay. Endotoxin was positive in 70% of the cases treated with antibiotics at an acute event for more than 5 days, while the incidence of bacteria was only 22%. One month after the sample collection, cases with a high concentration of endotoxin in MEE still tended to have effusion. These results suggest that endotoxin in MEE cannot be easily inactivated and may be involved in the development of acute otitis media into chronic otitis media with effusions.

Otitis media with effusion following inoculation of Haemophilus influenzae type b endotoxin

Lipopolysaccharide endotoxin (LPS) was extracted from Haemophilus influenzae type b by using Westphal's phenol water method. The ears of 40 adult male guinea pigs were subsequently inoculated with 10 micrograms/ml solutions of LPS by transmeatal injections. Groups of animals were then sacrificed from day 2 to day 24 after the injections to observe the pathological changes produced. Massive serous effusions filled the tympanic bullae on days 2 and 4, after which the amount of fluid present gradually decreased so that it could hardly be seen on day 11. Pathological changes found in the mucosa included marked interstitial edema, dilated capillaries, as well as elevated and thickened epithelium with intracellular edema. These findings gradually subsided by day 24. We believe that the major pathogenetic factors present were due to the transudation and injury of the middle ear epithelium disturbing mucociliary transport activity, with increased secretions participating somewhat in inducing the effusion. We further suggest that H. influenzae endotoxin may play an active role in the clinical development of otitis media with effusion.

Bacteriological investigation of secretory otitis media in children with cleft palate

Altogether 92 middle ear effusion samples from 89 children with cleft (lip) palate and secretory otitis media aged from two months to 15 years were cultured and analyzed bacteriologically. Known middle ear pathogens were isolated from 49 (53%), these accounted for 68% of all positive cultures. The frequency of occurrence of middle ear pathogens was significantly higher in the age group younger than 36 months. The most common bacteria found were S. pneumoniae, B. catarrhalis and H. influenzae. The only anaerobe was a strain of B. fragilis. We believe that by defining culture methods, more pathogens can be isolated from the middle ear of cleft children than has previously been reported. Pathogenic bacteria seem to be found with a higher frequency in children with cleft palate, when compared to normal children.

Endotoxin in middle ear effusions tested with Limulus assay

Endotoxin in middle ear effusion (MEE) from both children and adult patients with otitis media with effusion (OME) was assayed with the Limulus amoebocyte lysate test, in parallel with the detection of microorganisms. Whereas only 17% of MEE from adults, diluted 1:10 showed the presence of endotoxin, endotoxin was found in 69% of MEE from recent and recurrent cases in children, although microorganisms were isolated from only one-quarter of the samples. 83% of mucoid MEE from children contained endotoxin, compared with 41% of serous MEE. In older children, endotoxin was less frequently detected in accordance with the fact that the incidence of OME decreases with age. It is concluded that endotoxin may be one of the important factors in the pathogenesis of onset of, as well as in delayed recovery from OME in children.

The long-term outcome of nonsuppurative otitis media with effusion

Seventy-four children were enrolled in a double-blind placebo-controlled study to define the outcome of nonsuppurative otitis media with effusion (OME) over a 12-week period. Participants were randomly assigned to one of three treatment groups: pseudoephedrine (4 mg/kg/day), chlorpheniramine (0.35 mg/kg/day), or placebo. The children were reexamined at 2, 4, 8, and 12 weeks after enrollment unless earlier dismissed from the study because OME resolved or acute suppurative otitis media developed. Of the 66 children completing the study protocol, 44 percent had resolved OME, 38 percent developed acute suppurative otitis media, 14 percent had unresolved OME, and 4 percent developed severe hearing loss or medication side effects by the end of 12 weeks. The greatest incidence of both suppurative otitis media and resolution of OME occurred by 2 weeks of follow-up. There was no significant difference in resolution of effusion between treatment groups. Children who were 18 months of age or older with unilateral effusion had the best likelihood of resolution.

Endotoxin in middle-ear effusions from patients with chronic otitis media with effusion

Endotoxin concentrations were determined in middle-ear effusions (MEEs) from 89 children with chronic otitis media by using the Limulu's amoebocyte lysate assay. Mean concentrations of endotoxin in Haemophilus influenzae-positive and Streptococcus pneumoniae-positive MEEs were 157 and 21.8 ng/ml, respectively, and were significantly different (P less than 0.01). Endotoxin was also found in Gram stain-positive, culture-negative and Gram stain-negative, culture-negative MEEs, but the levels were not significantly different (P greater than 0.05). However, the endotoxin concentrations in both groups of culture-negative MEEs significantly lower than those found in MEEs that grew either H. influenzae or S. pneumoniae (P less than 0.05). These results show that endotoxin is present in a high percentage of human MEEs, including those that are culture negative, and may contribute to the pathogenesis of otitis media with effusion.

Secretory otitis media: microbiology of the middle ear and the nasopharynx

Specimens for bacterial culture were obtained from 117 children with secretory otitis media (SOM). From the nasopharynx Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis and group A streptococci were isolated in 79% of the patients. Of 168 ear exudates, 30 yielded growth (18%) from 26 of the patients (22%). Pneumococcal capsular polysaccharides could not be detected in exudates assayed by counterimmunoelectrophoresis. The recovery rate of bacteria from the ear exudates was significantly higher in patients with positive than with negative nasopharyngeal culture (p less than 0.05). The nasopharyngeal pathogens invading the middle ear in SOM seem to survive there for a period of time and are then replaced by other strains according to the fluctuation of the nasopharyngeal flora where approximately 40% of the strains were eliminated and replaced by other strains over a period of 12 to 13 days.

Experimental otitis media with effusion following middle ear inoculation of nonviable H influenzae

In order to test the hypothesis that nonviable bacteria can induce middle ear inflammation leading to persistent middle ear effusion (MEE), we conducted an animal experiment using formalin-killed Hemophilus influenzae, the bacterium reported to be the most common pathogen isolated from chronic MEEs. Over 70% of the chinchillas injected with formalin-killed H influenzae type b or a nontypeable isolate developed sterile, straw-colored serous MEEs, and exhibited histological evidence of extensive inflammatory changes of the middle ear mucosal connective tissue and epithelium. Control animals injected with pyrogen-free sterile saline did not exhibit any inflammatory changes or effusions in the middle ears. Our data suggest that endotoxin on the surface of H influenzae, a gram-negative bacterium, may be responsible for the induction of the otitis media with effusion. It is suggested that endotoxin (even when the organisms are no longer viable) may be responsible for the production of serous MEE and inflammatory changes in the middle ear.

Are immune complexes a factor in the pathogenesis of otitis media with effusion?

The authors investigated the presence of IgG-containing immune complexes in middle ear effusions as well as in middle ear mucosa and mastoid mucosa using the Raji cell radioimmunoassay (RIA), the inhibition of anti-antibody, and direct immunofluorescence tests. The Raji cell RIA showed positive results in two of 15 concentrated middle ear effusions but in none of 26 unconcentrated samples. The anti-antibody inhibition assay revealed immune complexes in two of 26 unconcentrated fluids. Thus, with two assays for soluble immune complexes, only four of 63 samples (6 per cent) were positive. Direct immunofluorescence of middle ear mucosa and mastoid mucosa resulted in localization of IgA and IgG in the plasma cells of the middle ear mucosa. A concomitant immunofluorescent staining for complement or immunoglobulin deposits along the basement membrane of the epithelium and/or blood vessels was not observed in 37 biopsy specimens. These findings do not support the concept that immune complexes are involved in the pathogenesis of otitis media with effusion.

Variation in bacterial count in otorrhea from cases of chronic otitis media depending upon the method of antibiotic administration

Patients with chronic otitis media (COM) were divided into two groups, one to be given Cephalexin (CEX) orally and the other to be given CEX ear drops locally. The counts of viable bacteria in otorrheal samples collected before and after CEX administration were determined. The incidence of decrease in the count of bacteria was higher in the group given ear drops than in the group given oral doses. The magnitude of decrease was greater in the former group. Various concentration of CEX representing the levels of the drug considered available at an otitis focus following oral administration were added to otorrheal preparations placed in biophotometer cells. After 24 hours of incubation, bacteria as undetected initially in the otorrhea were found in the biophotometer cells in 3 of 14 cases of COM.

Bacteria in the middle ear and ear canal of patients with secretory otitis media and with non-inflamed ears

Aerobic and anaerobic semiquantitative bacteriological cultures were taken from 110 mucoid middle ear effusions and the respective ear canals of 74 patients with secretory otitis media (SOM). Additionally, mucosal pieces from 20 non-inflamed middle ears and swabs from the ear canals were cultured similarly. Bacteria were found in 35 effusions and 65 ear canals with SOM; in both sites the most frequent species were S. epidermidis and S. aureus, and the species distributions were not significantly different in the sites. Ten effusions grew bacteria not culturable in the respective ear canal samples. Anaerobes were found in one effusion only. Nine non-inflamed middle ears revealed bacteria; the species distribution was no different from SOM, and four of the bacteria were not found in the ear canal of the same ear. In conclusion, there may be bacteria in the middle ear in the absence of inflammation and in SOM, but the role of viable bacteria seems to be nil in an established secretory otitis media.

Quantitative bacteriology in adenoid tissue

Over the past several years the indications for adenoidectomy have become increasingly controversial. Attempts to justify the operation in recurrent otitis media by correlating cultures of the nasopharynx with cultures of middle ear fluid have been inconclusive. Using quantitative bacteriologic techniques, we have studied the levels of aerobic and anaerobic bacteria per gram of tissue in adenoids removed from 48 patients. In seven patients, adenoidectomy was performed for nasal obstruction alone, in 17 patients for chronic serous otitis media, and in 24 patients for recurrent suppurative and serous otitis media. Using the criterion that greater than 10(5) organisms/gm of tissue constitutes infection, we found that 83% (20) of patients in the third group had infected adenoids, as opposed to only 15% (4) in the first and second group combined. Adenoid size measured radiographically did not correlate with the presence of infection. Adenoid size measured radiographically did not correlate with the presence of infection. When recurrent suppurative and serous otitis media are unresponsive to medical therapy including antibiotics and decongestants, adenoidectomy should be considered in addition to myringotomy and ventilation tubes.

Immune complexes and complement in serous and mucoid otitis media

The occurrence and quantity of immune complexes in middle ear effusion (MEE) and serum, as well as serum levels of complement (C) factors were investigated in patients with chronic otitis media. Immune complexes were demonstrated in 85% of the serous MEE and in 28% of the sera. Depressed Clq values and presence of abnormal complexes, composed of subcomponents of the first C factor, indicated a disturbed function of the C system. Activation of C by the classical pathway was demonstrated in 23% of the patients. Decreased levels of properdin were also noted. The disorders within the C system tended to normalize as the otitis subsided.