Acute otitis media. A clinical bacteriological and serological study of children with frequent episodes of acute otitis media

Acute Otitis Media

A typical case of acute otitis media in a pediatric patient is presented. The pathophysiology of the disorder, as well as its incidence, etiology, complications, and sequelae are discussed. Past treatment methods and current therapeutic recommendations pertaining to antibiotics and other adjuncts are included.

Serum intercellular adhesion molecule 1 variations in young children with acute otitis media

Acute otitis media (AOM) is an inflammatory reaction in the middle ear, most often occurring in young children. Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis are the most common bacteria isolated. Intercellular adhesion molecule 1 (ICAM-1) is involved in the innate immune response to infection by microorganisms, in effective antigen presentation, and in subsequent T-cell activation. Here we prospectively studied levels of serum soluble ICAM-1 (sICAM-1) before, at the time of, and after antimicrobial treatment of AOM in a group of 138 children ages 6 to 30 months. Middle ear fluids were collected by tympanocentesis to identify otopathogens. We found that (i) serum levels of sICAM-1 were significantly higher in S. pneumoniae-, nontypeable H. influenzae-, and M. catarrhalis-infected children than in well children (P < 0.001), confirming that a systemic inflammatory response occurs during AOM; (ii) sICAM-1 levels varied from no elevation (110 ng/ml) to elevation to high levels (maximum, 1,470 ng/ml) among children with AOM; (iii) in paired samples, sICAM-1 levels increased 4- to 20-fold when children developed AOM compared to their sICAM-1 levels before infection; and (iv) the level of sICAM-1 returned to the pre-AOM level at the convalescent stage of AOM after successful antimicrobial therapy. We conclude that AOM often causes a systemic inflammatory reaction, as measured by elevation of the serum sICAM-1 level, and that a high variability in sICAM-1 responses occurs with the presence of otopathogens during AOM.

The value of nasopharyngeal culture in predicting the etiology of acute otitis media in children less than two years of age

BACKGROUND

In selecting treatment of acute otitis media (AOM), knowledge of its etiology would be valuable. We revisited the possibility to use the nasopharyngeal culture of Streptococcus pneumoniae (Pnc) and Haemophilus influenzae (Hi) for predicting their presence in the middle ear fluid (MEF) during AOM.

METHODS

The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of bacterial culture of the nasopharyngeal aspirate (NPA) in predicting the presence of the same pathogen in the MEF were assessed during AOM events among children followed from 2 to 24 months of age.

RESULTS

The data comprised 586 AOM events. For Pnc, the sensitivity and NPV were high, 99% (95% confidence interval = 95-100%) and >99% (97-100%), respectively. The specificity and PPV were relatively low, 63% (57-68%) and 50% (43-56%). For Hi, the sensitivity and the NPV were lower (77%, 69-83% and 93%, 90-95%) than for Pnc, but the specificity and the PPV were higher (88%, 85-91% and 64%, 56-71%). The quantity of Pnc and Hi in the NPA was clearly related to their presence in the MEF. If both Pnc and Hi were found in the nasopharynx, Hi was more likely cultured from MEF.

CONCLUSION

Together with clinical and epidemiologic features of AOM, the nasopharyngeal culture can be helpful in selecting specific antimicrobial therapy.

Expression of cytokine genes during pneumococcal and nontypeable Haemophilus influenzae acute otitis media in the rat

Acute otitis media (AOM) elicits potent inflammatory responses from the cells of the middle ear mucosa as well as from infiltrating leukocytes. To explore host responses during experimental AOM induced by Streptococcus pneumoniae type 3 and nontypeable Haemophilus influenzae (NTHi), otomicroscopy findings and expression of cytokine genes in the middle ear were monitored up to 1 month postinoculation. The mucosa and infiltrating cells responded rapidly to the bacterial challenge. Otomicroscopically, AOM appeared 1 day after NTHi inoculation and 3 days after pneumococcus inoculation. Pneumococcal AOM was more severe than NTHi otitis, but in general, lower transcript levels were detected in pneumococcus-infected than in NTHi-infected animals. Interleukin-6 (IL-6) mRNA levels peaked at 3 to 6 h for both pneumococcus-infected and NTHi-infected animals. IL-1alpha, tumor necrosis factor alpha, and IL-10 mRNA levels peaked at 6 h for NTHi otitis and 1 to 3 days for pneumococcal otitis. Comparing otomicroscopy with expression profiles, it would appear that the majority of cytokine mRNAs had passed their peak before the AOM diagnosis could be made clinically. Only transforming growth factor beta mRNA followed a slower time course, peaking very late and continuing expression even after the AOM was otomicroscopically resolved. IL-2 and IL-4 mRNAs were not detected in any animal at any time. Most of the investigated cytokines are very early markers for AOM and may be involved in initiation of inflammation, but they would be poor targets for pharmacological manipulation since their levels decline before clinical signs appear.

Antibodies specific to outer membrane antigens of Moraxella catarrhalis in sera and middle ear effusions from children with otitis media with effusion

OBJECTIVE

Recent studies have shown that bacterial DNA is present in a significant percentage of middle ear effusions, suggesting that persistent bacterial infection may be more important in pathogenesis and recurrence of otitis media with effusion (OME) than previously considered. Although Moraxella (M.) catarrhalis is one of the most common pathogens of otitis media, relatively little is known about immune response to the organism. The objective of the present study is to investigate how systemic and local immune activities against M. catarrhalis may be associated with severity of OME.

METHODS

The antibody levels specific to outer membrane antigens of M. catarrhalis in sera and middle ear effusions (MEEs) from 59 children with OME were measured by enzyme-linked immunosorbent assay. Their ages ranged from 1 to 12 years with a median 5.0 years. The children were followed 1 year prospectively and classified into two groups with or without recurrent/persistent OME according to severity of OME during the follow-up 1 year.

RESULTS

Serum IgG, IgM, and IgA antibodies specific to outer membrane antigens of M. catarrhalis were detected in all samples and the median levels were 35, 0.93, and 1.2 microg/ml respectively. The MEE IgG, IgM, IgA, and secretory IgA antibodies were detected in over 95% samples tested and the median levels were 371, 158, 20, and 50 ng/mg total protein respectively. A comparison between acute and subacute/chronic phases revealed that the median levels of MEE IgG and IgM antibodies were higher at the acute phase (692 vs. 340, P = 0.06; 35 vs. 10, P = 0.02, respectively); while the MEE secretory IgA antibody level was increased at the subacute/chronic phase (74 vs. 35, P = 0.02). Either serum or MEE IgG antibody level was significantly lower in recurrent/persistent OME group than that in nonrecurrent/non-persistent OME group (13 vs. 43 ,microg/ml, P = 0.009; 238 vs. 577 ng/mg protein, P = 0.006, respectively).

CONCLUSIONS

These data provide additional information on the immunologic aspects of children with OME. Decreased serum and MEE IgG antibody levels specific to outer membrane antigens of M. catarrhalis may lead to failure to eliminate this organism, resulting in persistent and/or recurrent appearance of MEE.

A resolved pneumococcal infection protects against nontypeable Haemophilus influenzae: an evaluation of different routes of whole cell immunization in protection against experimental acute otitis media

A conferred cross-protection between Haemophilus influenzae type b (Hib) and nontypeable H. influenzae (NTHi) was demonstrated in a previous study of experimental recurrent otitis media. To explore cross-protection further, and to compare oral administration of whole cells with two more conventional routes for vaccination against acute otitis media (AOM), a total number of 79 rats were immunized perorally, subcutaneously and intrabullarly with H. influenzae or pneumococci and thereafter challenged in the middle ear with NTHi or Hib 4 or 9 weeks later. Otomicroscopic changes, bacterial cultures, and serum IgG antibody levels were monitored. The study demonstrated that while peroral administration did not elicit any protection, a resolved pneumococcal AOM could reduce the susceptibility to reinfection with NTHi. In the latter case no cross-reacting antibodies were detected, but the protective rate was 50% or more, and it was comparable with that found after subcutaneous or intrabullar immunization with homologous NTHi or Hib strains. The results suggest that the protection of the rat middle ear mucosa may involve unspecific responses.

Estimation of otitis media in ancient populations. A study of past and present Greenlandic Inuit

Examination of disease patterns in the past has often been difficult due to lack of morphological evidence. This study presents a new unbiased method for estimation of occurrence of infectious middle ear disease (IMED) in childhood. The method is based on the relation between IMED in childhood and small or asymmetric pneumatized cell areas in the temporal bones as seen on standardised X-rays. A polychotomous logistic regression model was applied on 434 pneumatized cell areas in temporal bones from 34 adult living Greenlandic Inuit, 56 adult crania from the 18th to the 19th century, A.D. and 127 adult Inuit crania from the pre-European colonization period (before A.D. 1721) of Greenland. The occurrence of IMED as designated by the model was eight out of 34 (23.5 per cent) in living Inuit, 10 out of 56 (17.9 per cent) in crania from the 18th to 19th century and six out of 127 (4.7 per cent) in crania from the pre-colonization period. These frequencies differed significantly (p < 0.002). The mean area size also differed significantly, thus indicating a change in occurrence of IMED and a decrease in area sizes from past to present in Greenland.

Effect of Haemophilus influenzae type b conjugate vaccine in combination with peroral immunization with Escherichia coli on experimental otitis media

The protective ability of a conjugated Haemophilus influenzae type b vaccine, ACT-HIB, used singly or in combination with orally administered Escherichia coli, was investigated in a rat model for acute otitis media. The humoral response to ACT-HIB was also analyzed. The study demonstrated that ACT-HIB vaccination resulted in a prompt antibody response, and that ACT-HIB was efficient in preventing middle ear infections caused by Haemophilus influenzae type b. The efficiency increased if the vaccine was combined with Escherichia coli. The results suggest that Escherichia coli could possibly be useful in the future as a vaccine vehicle, and since Haemophilus influenzae acute mastoiditis seems to be almost exclusively due to serotype b, the incidence of this infection may be reduced with the conjugated Haemophilus influenzae type b vaccines.

Experimental recurrent otitis media induced by Haemophilus influenzae: protection and serum antibodies

PURPOSE

To study whether acute otitis media caused by encapsulated or nontypeable Haemophilus influenzae confers cross-reactive protective immunity in an animal model system and to explore the possible involvement of various humoral specific antibodies in protection.

MATERIALS AND METHODS

Rats were intrabullarly challenged with H influenzae type b and two different nontypeable H influenzae strains. One month after the initial infection, the animals were rechallenged ipsilaterally or contralaterally with either a homologous or heterologous strain, and the susceptibility to reinfection was investigated by otomicroscopy.

RESULTS

The animals challenged and rechallenged with the type b strain were well-protected ipsilaterally and contralaterally, while the protection after homologous rechallenge with a nontypeable strain was partial in the ipsilateral ear and very poor in the contralateral ear. Middle ears previously infected with a nontypeable strain remained fully susceptible to infections with heterologous strains, but there was an indication of cross-protection in the animal groups where the first episode of acute otitis media was caused by type b and the second by a nontypeable strain. Using the Western blot technique and an enzyme linked immunosorbant assay, the serological response to different outer membrane proteins, especially protein D, of H influenzae during and after middle ear infection were investigated. The serological response from the type b infected animals were generally more distinct, while the antibody levels against protein D were lower in these groups compared with the groups infected with nontypeable strains.

CONCLUSIONS

These data indicate that H influenzae type-b-induced experimental otitis media results in a better protection than a nontypeable-induced, and H influenzae b confers a cross protection.

Antibody response to outer membrane protein of nontypeable Haemophilus influenzae in otitis-prone children

One of the major outer membrane proteins of nontypeable Haemophilus influenzae, P6, is highly conserved among strains, serves as a target for bactericidal antibody, and has been proposed as a possible vaccine candidate. The serum antibody response to P6 was studied in otitis-prone and normal children by an enzyme-linked immunosorbent assay. Of 20 otitis-prone children, 12 (60%) had a serum IgG antibody response to P6 after otitis media; however, the mean acute antibody level for the group, 4.6 micrograms/ml, was not significantly different from the convalescent level, 5.4 micrograms/ml. Anti-P6 antibody levels were also measured longitudinally for 10 to 25 months in 30 otitis-prone and 13 healthy children. Antibody levels increased sevenfold in the normal group compared with less than three-fold for the otitis-prone group and were significantly higher in the normal children after the age of 18 months (p < 0.05). Finally, otitis-prone children who had two or more episodes of otitis media with nontypeable H. influenzae did not have an anamnestic antibody response to P6. The failure to recognize P6 as a specific immunogen may account for recurrent infections. Moreover, the data suggest that otitis-prone children may not respond adequately to a vaccine containing P6.

Nasopharyngeal bacterial flora in otitis prone children treated with immunoglobulin

The present study was undertaken to evaluate possible beneficial effects of regularly given, long term immunoglobulin prophylaxis of children below 2 years of age with recurrent acute otitis media (RAOM). The nasopharyngeal bacterial flora and the frequency of acute otitis media (AOM) and secretory otitis media SOM were studied. Every second of 44 children with 3 or more periods of AOM during the last year received immunoglobulin intramuscularly (Gammaglobulin Kabi 165 mg/l, 0.45 ml/kg b.w.) every third week for 6 months, while the other 22 children served as controls. All children were followed for 12 months. Immunoglobulin prophylaxis neither influenced the nasopharyngeal flora, nor the frequency of AOM or SOM periods. Children with AOM or SOM more often harbored bacterial pathogens in their nasopharynx than children with normal middle ear status. Also, the immunoglobulin prophylaxis did not influence the increased frequency of bacterial pathogens in the nasopharynx of children attending public day care or family day care as compared to those taken care of at home.

Responses to rubella, tetanus, and diphtheria vaccines in otitis-prone and non-otitis-prone children

Delayed immunologic maturation--among other things based on a selective lack of antibodies against some acute purulent otitis media (AOM)-associated pneumococcal types--has been proposed in children with recurrent AOM (rAOM). To further elucidate the immunologic response in these children, we compared the antibody responses to diphtheria, tetanus, and rubella vaccinations in 13 children with rAOM and 29 children without AOM. The children took part in a prospective study from birth to the age of 3 years. The antibody response to the rubella vaccine was significantly lower in the children with rAOM. The responses to tetanus and to diphtheria did not differ between children with and without rAOM. Thus, the results indicate that in addition to the known lack of antibodies against pneumococcal polysaccharide antigens, a lower antibody response against at least one protein antigen may exist in otitis-prone children.

Effect of gammaglobulin on pneumococcal otitis media in the rat

Previously it has been found possible to induce pneumococcal AOM that closely resembles human infections, in the rat. In this study, the rat model has been used to study the possibilities to affect the infection by administration of gammaglobulin. The gammaglobulin was administered either systemically by intravenous injection of 0.2 g/kg bodyweight in 15 rats, or topically when 8 mg was instilled into the middle ear cavity of 18 rats. Although intravenous administration in this model failed to provide protection from AOM, topical administration simultaneously with the bacterial challenge was successful.

Pneumococcal serum antibody concentrations during the first three years of life: a study of otitis-prone and non-otitis-prone children

One hundred and thirteen children were followed prospectively from birth until the age of 3, serum being obtained from cord blood, and at the ages of 3, 6, 12, 18, 24, 30 and 36 months. Thirteen children developed recurrent acute otitis media (rAOM), 29 remained very healthy and the remaining children formed an intermediate group. Cord serum concentrations were determined of total IgG class, of IgG1 and IgG2 subclasses, as well as of specific IgG antibodies against the pneumococcal capsular types, 3, 6A and 19F. The specific pneumococcal IgG as well as IgA and IgM antibodies were also followed in the sequential serum samples up to the age of 3 in the rAOM and healthy children. Despite total IgG class and IgG1 and IgG2 subclass concentrations being of the same magnitude in cord serum of rAOM (median: 11.15, 7.48 and 2.16 g/l for IgG, IgG1 and IgG2, respectively) as in that of healthy children (median: 10.21, 8.16 and 2.16 g/l, respectively), both in cord serum and in most serum samples drawn during the first year of life, specific IgG antibodies against types 6A and 19F, but not against type 3, were significantly lower in the rAOM group than in the healthy children. In the intermediate group, cord serum concentrations of specific IgG antibodies to type 6A were of the same magnitude as in the healthy children. The only significant difference in specific IgM and IgA antibody concentrations against types 3, 6A and 19F between the two groups was noted for type 6A antibodies at 36 months of age where rAOM children exhibited lower values. The results indicate an association between pre-existing low specific IgG antibody levels against AOM-associated pneumococcal types and the development of rAOM.

Nasopharyngeal secretory immunoglobulins in children with recurrent acute otitis media and secretory otitis media

Secretory IgA (SIgA) and secretory IgM (SIgM), total IgA and total IgM were measured in plasma and nasopharyngeal secretions (NPS) from young children with different degrees of otitis proneness. Significantly higher levels of plasma IgM and lower levels of NPS-SIgM were found in children with recurrent episodes of acute otitis media (rAOM) compared with children suffering from secretory otitis media (SOM) and healthy controls. Both plasma IgA and NPS-SIgA were evenly distributed in the three groups of children investigated, and in most children the levels of NPS-SIgA exceeded plasma IgA levels. Plasma SIgA was significantly increased in children with rAOM and SOM, probably resulting from frequent occurrence of inflammatory events at the nasopharyngeal level. No correlation could be demonstrated between NPS-SIgA and plasma IgA, or between NPS-SIgM and plasma IgM. Also, for both NPS-SIgA and NPS-SIgM, there was no correlation with age. A negative correlation was observed between the transudation index of albumin to the nasopharynx and the ratio of NPS-SIgA to total NPS-IgA. A ratio of 1 (100%) corresponded to a transudation index of 8%. The ratios of NPS-SIgA to total NPS-IgA varied considerably and a range of 39%-88% could only to some extent be explained by transudation of plasma IgA to NPS. The results of the present study show that the children with rAOM and SOM are well furnished with locally produced SIgA antibodies at the nasopharyngeal level. In children with SOM, the nasopharyngeal hypofunction in the case of low NPS-SIgM seems to be less pronounced compared with that of otitis-prone children.

Role of attachment for the virulence of Streptococcus pneumoniae

Adherence of microorganisms to mucosal surfaces is a general phenomenon among microorganisms infecting the human host. Its role for persistence and colonization as well as production of local inflammation is well established. This paper describes the adhesion of Streptococcus pneumoniae to human epithelial cells. Strains from various anatomical sites or diseases are compared for attaching capacity. Isolates from the same host but at different times are also compared. The molecular mechanisms, the so-called adhesin-receptor interactions, are partially described. The pneumococcus recognizes a sugar sequence; GlcNAc beta 1-3Gal; on the surface of the host epithelial cell. Glycoconjugates containing this disaccharide act as receptors for adhering pneumococci. The adhesin in pneumococcal attachment is less well characterized. It is a heat and trypsin sensitive component, most likely a peptide, which forms a bridge between the receptor and an anchoring site in the pneumococcal cell wall. Receptor active saccharides are part of the adhesion-inhibitory activity found in human milk.

Humoral immune response in acute otitis media

A short summary of the middle ear mucosal defence system and the characteristics of the infecting bacteria associated with purulent acute otitis media (AOM) is given. Data on humoral immune factors in middle ear effusions and serum during AOM are presented and the possibility that children with frequent recurrences of AOM exhibit an impaired ability to produce antibodies against AOM-associated antigens is discussed.

The effect of intravenous immunoglobulin treatment in recurrent acute otitis media

The effect of serial intravenous infusion of human immunoglobulin on the frequency of acute otitis media (AOM) episodes and on other upper respiratory tract infections was prospectively studied in a group of 22 otitis-prone children, 1-4 years old. After pair-matching, the children were allocated to immunoglobulin treatment or to a control group. Increased specific IgG antibody activities against pneumococcal types associated with recurrent AOM (rAOM) were generally achieved, but no significant difference was noted in the frequency of AOM attacks or other respiratory tract infections between the immunoglobulin-treated children and their pair-matched untreated controls. The results indicate that, although serum antibody activities against bacteria associated with AOM are increased by immunoglobulin infusions, this does not prevent the development of AOM in children suffering from rAOM.

Antibody activity before and after pneumococcal vaccination of otitis-prone and non-otitis-prone children

The antibody activity of the IgM class and subclasses of IgG and IgA against pneumococcal bacteria of types 3, 6A and 19F was studied before and after administration of a pneumococcal vaccine (Pneumovax) in a group of children with recurrent acute otitis media (rAOM) and in groups of non-otitis-prone children. Only occasionally was there a significant rise in antibody activity after vaccination in any of the groups. There was no difference in the response to vaccination between rAOM children and healthy children. However, rAOM children exhibited lower antibody activities in most Ig subclasses against pneumococcus type 6A--a common causative agent in AOM--before as well as after vaccination compared with the healthy children. The results indicate that the response to vaccination is equally poor in all children, irrespective of whether they have a history of frequent attacks of acute otitis media, but, in contrast to healthy children, the rAOM children seem to have an inability to mobilize antibodies in response to infections with some pneumococcal types.

Recurrent acute otitis media--prophylactic penicillin treatment: a prospective study. Part I

Recurrent acute otitis media (RAOM) is a distressing clinical manifestation of middle ear pathology, mainly expressed in the first two years of life. In this controlled study, prophylactic treatment by phenoxymethyl penicillin reduced significantly the frequency of RAOM in 60 children, as compared to 48 children who received a short ampicillin course only on the occasion of an acute otitis media episode. The importance of breastfeeding, age at initial episode, the type of treatment given and the pertinent literature is discussed. A working hypothesis of this prophylactic treatment is suggested.

Risk factors affecting the occurrence of acute otitis media among 2-3-year-old urban children

The factors affecting the occurrence and recurrence of acute otitis media (AOM) were studied among 471 2-3-year-old children in two cities in Finland. Of these children, 188 had experienced greater than or equal to 3 attacks of AOM, 76 had had 1-2 attacks and 207 no otitis attacks (= control group). The study showed that the risk of recurrent AOM was increased among those children attending day-care nurseries as well as among those who had several siblings. Proneness to rhinorrhea and exposure to passive smoking at home was associated with an increased risk of AOM, while prolonged breast-feeding (greater than 6 months) seemed to reduce it. No correlation was found between the risk of recurrent AOM and the place of residence or type of housing, the parental otitis history, or atopic diathesis of a child. Thus the study suggested that to protect a young child from AOM we should promote breast-feeding and home-care for babies as well as avoid smoking in the home.

A prospective study demonstrating an association between plasma IgG2 concentrations and susceptibility to otitis media in children

Plasma IgG subclass levels of 20 children, 12 and 32 months of age, who were susceptible to acute purulent otitis media, were compared with those of 20 age-matched control children. The IgG2 levels were significantly lower in the otitis-prone group, with a mean of 0.58 +/- 0.30 g/l at 12 months of age (controls 0.85 +/- 0.39) and 0.82 +/- 0.30 at 32 months of age (controls 1.38 +/- 0.49). Otitis-prone children with IgG2 levels less than or equal to 0.58 g/l (at 12 months of age) were found to suffer from Haemophilus influenzae infections 2.6 times as often as those with IgG2 levels greater than 0.58 g/l. On the other hand pneumococci were found 1.9 times as often in the group with IgG2 level greater than 0.58 g/l, as in the group with IgG2 level less than or equal to 0.58 g/l. Otitis proneness seems partly to be due to an immunological incompetence of IgG2, which also influences the bacterial spectrum of the infections.

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.

Pneumococcal antibodies and complement during and after periods of recurrent otitis

Streptococcus pneumoniae frequently accounts for acute purulent otitis media (AOM) episodes. Recurrences are common and are most often caused by pneumococci of groups 6, 19 and 23. In 15 two-year-old children with recurrent AOM ( rAOM ) complement (C) components and antibodies against various pneumococcal capsular polysaccharides were analyzed during the acute phase of an AOM episode and 6 years later. Comparison was made with findings in non-otitis-prone children of comparable age. In contrast to non-otitis-prone children, 60% of children with rAOM had no detectable IgG antibodies against the pneumococcal capsular polysaccharides 6A or 19F. Analysis of C1 subcomponent complexes together with the finding of relatively low C1q concentrations gave evidence of disturbed C1 function in the acute phase of rAOM . At the 6-year follow-up antibodies against all the investigated pneumococcal capsular polysaccharides had increased in most of the children, but low IgG antibodies to type 6A polysaccharide were still more frequently found in the former rAOM children than in non-otitis-prone children. The C profiles had normalized at follow-up. These findings indicate a reduced ability in rAOM children to respond adequately with IgG antibodies to pneumococcal types encountered in rAOM . The combination of low antibody concentrations and the interference with the complement system and efficient opsonization through classical pathway activation could possibly contribute to the development of rAOM .

Incidence of acute otitis media

The occurrence of acute otitis media was studied over a one-year period in a total population of 146822 persons living in different parts of Finland. Of these 146822 persons, 4583 experienced a total of 6518 otitis attacks giving an annual incidence rate of 4.44% (4.48% in males and 4.07% in females, P less than 0.001). Acute otitis media was strikingly concentrated in the youngest age groups, with the highest annual incidence rates, in the order of 50%, found in infants younger than 2 years. Half of all the episodes occurred before the age of 33 months. The relative risk of getting acute otitis media was about 200 times higher during the first 2 years of life than as an adult. The occurrence of otitic episodes followed seasonal variations, and in urban areas the incidence was significantly (P less than 0.001) higher than in the countryside.

Streptococcus pneumoniae and Haemophilus influenzae in nasal cultures during acute otitis media

Middle ear fluid (MEF) aspirates and nasal swabs of children with acute otitis media (N = 255, age 2-6 yrs) were cultured by standard bacteriological methods. In addition, counterimmunoelectrophoresis and latex agglutination were applied to detect pneumococcal polysaccharide antigens (Pn-ag) in MEF. When the nasal culture grew Streptococcus pneumoniae (Pn), Pn was also present in 49% (73/148) and Pn-ag in 64% of the MEF cultures. If Haemophilus influenzae (Hi) appeared in the nasal culture. Hi was present in 41% (25/61) of the MEFs. There was a negative correlation between the growth of Pn or Hi in the nasal culture and the presence of other bacteria in the MEF. However, in spite of these correlations the nasal culture was concluded not to be useful in predicting the MEF bacteria.

Study of antibody levels in children with purulent otitis media

A series of episodes of acute otitis media were studied with reference to the bacterial findings in the nasopharynx and the specific antibody response in a group of children nine months to ten years of age, with previous frequent episodes of acute otitis media, Serum IgG, IgM and IgA antibody levels against five polysaccharide antigens, namely Haemophilus influenzae type b and Streptococcus pneumoniae types 3, 6, 19 and 23, were studied by means of an enzyme-linked immunosorbent assay. The selection of polysaccharide antigens was based on isolation frequency. The sera to be tested were tenfold serially diluted. An extinction of 0.2 over the base was taken as the end-point titer and expressed as in-log10. The results showed that most children including those under three years of age showed increasing homologous antibody titers at an infection, or had already initially very high antibody titers, especially of the IgG class. The titers reached levels of 10(4) to 10(5). In some cases, however, it could be shown that high serum antibody titers did not give protection against a new infection with the same serological type of bacteria. It was also demonstrated that most children, regardless of age, had IgG and IgM titers against the heterologous antigens. In some cases the levels were quite high (10(3) to 10(4)). However, the IgA antibody levels were lower and in a considerable number of samples antibodies were not even detectable.

Complement and C1q binding substances in otitis media

Complement activation, as shown by increased amounts of complexes composed of C1r-C1s-C1 IA, and abnormal complexes of C1r-C1s were demonstrated in serum from patients with acute pneumococcal and chronic otitis media, serous or mucoid respectively. C1q binding substances were shown in middle ear effusions and in sera from patients with chronic serous otitis media. Presence of immune complexes and/or bacterial products capable of binding c1q results in formation of C1r-C1s-C1 IA complexes and may also cause the generation of C1r-C1s complexes. Such a dissociation of the C1 component will compromise the important opsonic function of the classical pathway.

Acute gram-negative bacillary infections of middle ear and mastoid

Thirty-three patients with acute purulent otitis media and mastoiditis caused by Gram-negative bacilli are presented. The main features of the disease include: predilection for young male infants, a high rate of complications that include sepsis, mastoiditis and osteomyelitis of the base of the skull. Patients that are diagnosed early respond well to drainage and ventilation of the infected middle ear combined with in vitro effective antibacterial therapy. Patients that receive prior inappropriate antibacterial therapy tend to have prolonged courses and require mastoid surgery. It is suggested that early myringotomy and bacterial cultures be performed in all patients with acute middle ear infections.

Persistence of middle-ear effusion after acute otitis media in children

We observed the frequent occurrence of persistent middle-ear effusion in children with acute otitis media and followed them according to standard procedures for otologic diagnosis. We performed a life-table analysis to identify risk factors for such persistent disease. Sixty-two patients were free of middle-ear effusion at one or more clinic visits two to 13 weeks after presentation and were considered cured; 45 had effusion at all clinic visits during this period and were defined as having persistent effusion. The life-table analysis showed that the relative risk for persistence was 3.8 times higher in children less than 24 months of age as compared with children 24 months of age or older (P less than 0.001) and that this risk was 2.8 times greater for white as compared with black children (P less than 0.01). Other factors examined were not identified as significant risk factors. Persistent middle-ear effusion may be associated with impaired hearing and appears to be the most important sequela of otitis media.

Effects of adenoidectomy: a controlled two-year follow-up

A prospective controlled study was made on the effect of adenoidectomy performed on 105 children. For various reasons, mainly severe long-standing nasal obstruction, 29 children were omitted from the study. The remaining 76 children were randomly divided into two groups, one adenoidectomy, and one control. Both groups were slightly reduced in number due to drop out. Thus 36 adenoidectomized children were followed during one year and 35 children during two years. The corresponding numbers for the children in the control group were 37 and 33. The incidence of common cold, purulent and serous otitis media and moderate nasal obstruction was compared in the two groups. A considerable reduction in the incidence of these variables was observed in both groups. The occurrence of moderate nasal obstruction was reduced more among the operated than among the unoperated children. The difference was only slightly significant during the first and not at all during the second year. Regarding the other variables, the differences were not significant, implying that adenoidectomy seems to have no effect on the incidence of common cold, serous and purulent otitis media.

R-factor involvement in a local outbreak of ampicillin-resistant Haemophilus influenzae infections

In a Swedish nursery 11 of 15 children harboured non-encapsulated Haemophilus influenzae in their nasopharynx. Six children had ampicillin-resistant and beta-lactamase-producing isolates. Five of these children had otitis whereas one was healthy. In order to identify the origin of the H. influenzae isolates their O-antigen determinants were studied by an immunodiffusion technique. 18 different rabbit antisera were used. For each isolate an O-antigen pattern was recorded. Five of the 6 resistant isolates had the same O-antigen pattern, indicating that their origin was one strain. The 6th isolate was from another strain. Different isolates from the same strain were found to be either sensitive or resistant to ampicillin. In one child the H. influenzae lost its resistance during trimethoprim-sulphamethoxazole treatment. It is concluded that an R-factor may have been involved in the distribution of ampicillin resistance in the H. influenzae studied. Previous in-vitro studies have shown that beta-lactamase production can be transmitted by a plasmid among H. influenzae strains.