Clin. Otoluryngcil. 1992, 17, 53 1-534

Bacteria and endotoxin in middle ear fluid and the course of secretory otitis media THERESE OVESEN* & THOMAS LEDET *Ear, Nose and Throat Department and tResearch Laboratory for Biochemical Pathology, Aarhus University Hospital. Aarhus. Denmark

Accepted for publIcdtion 3 July 1992 OVESEN ‘I. & LEDET T.

(1992) Clin. Otolaryngol. 17, 531-534

Bacteria and endotoxin in middle ear fluid and the course of secretory otitis media To determine the influence of bacteria and bacterial products on the course of secretory otitis media (SOM) following ventilation tube insertion we examined 68 middle ear effusions from 57 children with SOM. Swabs were taken for bacteriological examination and the content of endotoxin was measured. The children were followed up for one year and relapse of SOM was recorded. Bacteria were present in 38% of effusions and endotoxin was detectable in 96%. Relapse occurred in 26% of the patients and was related to the presence of bacteria in the original effusion ( P < 0.01). The concentration of endotoxin, however, did not correlate with the course of SOM. Keywords

bacteria endotoxin secretory otitis media prognosis

Previous studies have suggested that negative middle ear pressure and micro-organisms are pathogenic factors in secretory otitis media (SOM). Traditionally SOM is treated by insertion of ventilation tubes consistent with the ex-vacuo therapy, but apparently not treating any infective causes of the condition. Both clinical and experimental studies have indicated endotoxin from Gram negative bacteria to be of major importance in the development of SOM.’-’’ Endotoxin is a strongly active bacterial product stimulating the immune response.’ Thus, it is capable of inducing and maintaining inflammation of the middle ear mucosa.”* According to these findings, elimination of micro-organisms and their products seems to be important in the treatment of SOM. However, it has been shown that endotoxin may persist in the middle ear despite administration of antibiotic^.^ It is difficult to evaluate the significance of the different pathogenic factors in SOM but it appears reasonable to suggest that an interaction between negative middle ear pressure and micro-organisms exists. Insertion of a ventilation tube results in normalization of the middle ear pressure, Correspondence:Therese Ovesen, Ear, Nose and Throat Department, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.

thereby dealing with one of the possible causative factors. What about the microbiological findings? Are they just secondary and insignificant without the need for treatment and how d o they interact/interfere with ventilation tube insertion? The aim of the present study is to determine the incidence of bacteria and endotoxin in the middle ear fluid in children with SOM and to relate this to the course of the disease following ventilation tube insertion.

Materials and methods SAMPLES

The fluid from 68 middle ears was collected from 57 Caucasian children (median age 28 months, range 12-170 months, 20 girls, 37 boys, all attending nursery schools) undergoing insertion of ventilation tubes according to the following criteria: ( I ) SOM for at least 3 months verified by otomicroscopy and tympanometry and ( 2 ) hearing impairment accompanied by speech disturbance or (3) adenoid symptoms. Of the samples, 22 were obtained from I I children with bilateral SOM; 46 from children with unilateral SOM. All effusions were of the mucoid type and none of the children had been treated with antibiotics for the 5 weeks

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prior to the study. The middle ear fluid was aspirated through a sterile ear speculum by means of a sterile, pyogenfree middle ear aspirator and collected in a sterile, pyogenfree syringe. Swabs for bacterial examination and antibiotic resistance were obtained from the fluid before storage a t - 20°C for the assay of endotoxin. Post-operatively the children underwent ENT-examination with otomicroscopy and audiometry after 2 weeks and every third month for a year. Patients with a non-purulent middle ear effusion for more than 2 weeks within this year were identified.

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Bacteria and endotoxin in middle ear fluid and the course of secretory otitis media.

To determine the influence of bacteria and bacterial products on the course of secretory otitis media (SOM) following ventilation tube insertion we ex...
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