Antibody activity in otitis media with effusion

The immunoregulatory and allergy-associated cytokines in the aetiology of the otitis media with effusion

Inflammation in the middle ear mucosa, which can be provoked by different primary factors such as bacterial and viral infection, local allergic reactions and reflux, is the crucial event in the pathogenesis of otitis media with effusion (OME). Unresolved acute inflammatory responses or defective immunoregulation of middle inflammation can promote chronic inflammatory processes and stimulate the chronic condition of OME. Cytokines are the central molecular regulators of middle ear inflammation and can switch the acute phase of inflammation in the chronic stage and induce molecular-pathological processes leading to the histopathological changes accompanying OME. In this review we present cytokines identified in otitis media, immunoregulatory [interleukin (IL)-2, IL-10, transforming growth factor-beta]) and allergy associated (IL-4, IL-5, granulocyte-macrophage colony-stimulating factor), as crucial molecular regulators, responsible for chronic inflammation in the middle ear and the chronic condition of OME.

Bacteriological and PCR analysis of clinical material aspirated from otitis media with effusions

Otitis media with effusions (OME) can lead to significant hearing loss in childhood. Although previous studies have shown that bacterial DNA is present in a significant percentage of effusions sterile by culture, whether the DNA represents viable organisms or 'fossilized remains' is unknown. The aim of the present study was the determination of Streptococcus pneumonia, Moraxella catarrhalis and Haemophilus influenza in the clinical materials from OME. For this purpose, effusion samples aspirated from the mid-ear were analyzed bacteriologically. Samples were also tested with polymerase chain reaction (PCR) assay. A total of 37 samples obtained from 20 patients aging between 4 and 14 were analyzed. In 17 patients, both ears demonstrated effusions, whereas in three patients, only one ear had effusions. In aerobic bacterial culture assays, nine samples (24.3%) showed bacterial growth. None of the samples were positive for anaerobic culture experiments. PCR analysis of the samples showed that 35 samples (94.5%) contained bacterial DNA. In 19 samples, only one bacterial species and in 16 samples more than one bacterial species were detected. The results of this study demonstrate that effusion fluid from otitis media cases contain a battery of bacterial species and these bacteria might play roles in the pathogens of OME. Our results indicate the PCR technique is more specific and sensitive in detection of bacteria in middle-ear effusion of OME, compared with conventional methods.

Bacteriological findings and persistence of middle ear effusion in otitis media with effusion

The bacteriology of middle ear effusion (MEE) of asymptomatic otitis media with effusion (OME) was studied in 165 children, aged 5 months to 12 years, from the MEE samples obtained during tympanostomy under general anaesthesia in 1993-1994. MEE had persisted for 1 to 12 (mean 3.5) months. Major otitis pathogens (S. pneumoniae, H. Influenzae, B. catarrhalis and S. pyogenes) were cultured in 41% of the children under 2 years of age and in 17% of older children (p < 0.001). Respiratory infections and attacks of acute otitis media (AOM) during the last 6 months were also more frequent in children younger than 2 years (p < 0.001). The proportion of S. pneumoniae (25%) and H. influenzae (38%), but not of other bacteria, was higher in the children with less than 2 months' persistence of MEE as compared with those with a longer duration (8% and 3%) (p < 0.01). After 2 months, the occurrence of different bacteria remained relatively unchanged until 6 months' persistence of MEE, and thereafter no pathogens were culturable. Among the children adenotomized earlier, the proportion of those with major otitis pathogens in MEE was 8% compared with 32% in non-adenotomized children (p = 0.02). S. pneumoniae, B. catarrhalis or S. pyogenes were not culturable in any of the adenotomized children, while MEE grew them in 25% of the non-adenotomized children (p < 0.001). Since the MEE bacteriology of OME with less than 2 months' persistence resembles that of AOM, it may be that these cases represent a transitory phase between AOM and an established OME.

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.

Current concepts of pathogenesis of otitis media: a review

A number of important factors singly or in combination contribute to the pathogenesis of otitis media. These are poor tubal function, upper respiratory viral infection, bacterial adherence and nasopharyngeal flora, and immune status of the host. One of the important functions of the tubotympanum is to protect the middle ear from invading microbes. The host has available a number of strategies for this function including mucociliary protection, antibacterial secretory products, and specific immunodefenses. The microbes also possess the capability of escaping host defenses by enhancing their ability to adhere to mucosal surfaces, impairing mucociliary function and evading phagocytosis. Once microbes gain entrance to the middle ear, the microbes must overcome phagocytosis and immunodefense of the host, leading to otitis media. Recent data further indicate that specific qualitative and quantitative deficiencies in the immune system of children may predispose certain children to develop otitis media. These deficiencies appear to be in part due to a lack of maturity of the child's developing immune system as well as functional defects that are attributable to genetic or other unknown factors.

Immunologic and cytologic studies in otitis media with effusion

Detection of immune complexes (ICs) of IgG, IgM, or IgA isotypes in middle ear effusions (MEEs) by the solid-phase anti-C3 ELISA and cytologic analyses of MEEs were done in 245 patients with otitis media with effusion (OME). In 320 ears, the clinical classification was acute, 10.3%; subacute, 16.6%; chronic, 73.1%. In the cytologic analyses, the predominant types in each clinical stage were as follows: neutrophil dominant (N) type (63%) in acute cases; neutrophils and lymphocytic (Mixed) type (37%) in subacute cases; and cellular remnant (CR) type (37.8%) in chronic cases. In all the clinical stages IgG-ICs were positive in over 50% of cases and acute cases showed the highest positive rate (64%). IgA)ICs were found in all clinical stages and the highest positive rate was found in subacute cases (67%). In chronic cases, MEEs of N type showed the highest IgG-ICs level and positive rate (75%). These results suggested that immune complexes formed in the middle ear cavity might play an important role in the prolonged inflammatory process of OME through the complement activation following chemotaxis of neutrophils.

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.

Late results and complications of tympanostomy tube insertion for prophylaxis of recurrent purulent otitis media in pediatric age

We have evaluated from a clinical and functional point of view a total of 61 children (37 boys and 24 girls with a median age of 3 years, range 4 months to 6 years) who had been submitted before 1978 to insertion of tympanostomy tubes (in a total of 131 ears) for prophylaxis of recurrent purulent otitis media. Of these, 67.6% remained free from recurrencies after removal or extrusion of grommets, whereas in the remaining group discharge could be cured with local and/or general antibiotic treatment. Sixteen cases had tympanic calcifications, 6 an atrophic drum, and 10 a severe tympanic retraction, but only 8 out of these 32 cases had signs of conductive hearing loss (average loss 20 dB on frequencies from 500 to 2000 Hz). Further complications observed in this follow-up have been perforations (6 cases) and one case of migration of the tube into the tympanic cavity. No cholesteatoma has been observed in our series. A few considerations can be drawn from these observations: insertion of grommets, correctly performed in the anterior-inferior part of the drum appears to prevent a large percentage of recurrencies, and should therefore be considered, even in the long-term, an adequate prophylaxis for the otitis-prone child; complications as seen during a long follow-up period are relatively few, can be cured, and have a modest functional impact.

Nasopharyngeal carriage of bacteria in otitis-prone and non-otitis-prone children in day-care centres

During a 2-year period nasopharyngeal specimens were taken monthly on scheduled occasions as well as at episodes of acute otitis media (AOM) from a population of children attending day-care centres. The carriage rates of pneumococci, Haemophilus influenzae and Branhamella catarrhalis in 26 otitis-prone (OP) children when asymptomatic and at episodes of AOM were compared with the carriage rates in 36 non-otitis-prone (NOP) children. Pneumococci, H. influenzae and B. catarrhalis were found as frequently in NOP as in asymptomatic OP children. At AOM episodes only B. catarrhalis was found significantly more often than in the scheduled cultures. The frequencies of the six most commonly isolated pneumococcal types/groups (6, 23, 19, 14, 11, 18) were similar in the cultures taken from NOP and OP children on scheduled occasions as well as in cultures taken at AOM episodes. In contrast to the NOP children H. influenzae and B. catarrhalis were isolated less frequently in the 3-4-year-old than in the 2-3-year-old asymptomatic OP children. Our data indicated that the presence of pneumococci, H. influenzae or B. catarrhalis in the nasopharynx does not per se increase the risk for the development of AOM.

Antibiotic-resistant bacteria in otitis media with effusion

Eighty-two bacterial isolates recovered from the middle ear effusions (192) of children with otitis media with effusion (OME) were tested for antibiotic sensitivity. Nearly 50% of all bacteria isolated were found to be resistant to penicillin, and in particular, 61% of the Haemophilus isolates were penicillin-resistant; 48% of the Haemophilus isolates were ampicillin-resistant. In addition, we we compared the bacterial recovery rate from effusions of patients who were receiving antibiotics with those who were not. Among patients who were receiving antibiotics, 33% of the effusions were culture positive, while 82% of the effusions were culture positive in the patients who were not given antibiotics. These results are discussed with respect to the possible role of bacteria in the pathogenesis of OME.