Otitis media: a preventable disease? Proceedings of an international symposium organized by the Marcel Mérieux Foundation, Veyrier-du-Lac, France, February 13 to 16, 2000

Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae strains isolated from middle ear fluids of children aged 0–24 months with acute otitis media

Az akut otitis media a két éven aluli korcsoport egyik leggyakoribb betegsége, amelynek legfőbb bakteriális kórokozója a Streptococcus pneumoniae . A jelenleg elérhető, hét szerotípus elleni védelmet adó konjugált pneumococcusvakcina világszerte jelentős hatással van az otitis media, különösen a vakcinában megtalálható hét szerotípusba tartozó pneumococcusok okozta otitis media előfordulására. Az oltás hatékonysága az adott régióban észlelt otopatogén pneumococcus törzsek szerotípus-megoszlásától függ. A vizsgálat célja: Kétévesnél fiatalabb gyermekekben középfülgyulladást okozó S. pneumoniae törzsek szerotípusának és antibiotikum-érzékenységének meghatározása, és ezek összehasonlítása a nemzetközi adatokkal. Betegek és módszerek: 2002 és 2005 között 10 budapesti gyermekgyógyászati intézményben megjelent, 0–24 hónapos korú, otitis media acutában szenvedő gyermek dobüregi váladékából 73 S. pneumoniae törzset izoláltunk, amelyeket a Fővárosi Szent László Kórház Mikrobiológiai Laboratóriumában identifikáltuk és Quellung-reakció segítségével szerotipizáltuk. Az antibiotikum-érzékenységi vizsgálatokat a laboratórium a Magyar Mikrobiológiai Társaság által elfogadott standard módszerek alapján végezte és értékelte. Eredmények: A 73 izolált S. pneumoniae törzs 14 szerotípust reprezentált. A 14 (13,7%), a 19F (13,7%), a 6B (13,7%), a 23A (11%) és a 3 (9,6%) szerotípusok voltak a leggyakoribbak. A törzsek 63%-a tartozott a hét szerotípus ellen védelmet nyújtó konjugált vakcinában megtalálható szerotípusba. A penicillinre mérsékelten érzékeny törzsek aránya 41% volt, e törzsek 90%-a a vakcina szerotípusaiba tartozott. Penicillinrezisztenciát nem észleltünk. A leginkább rezisztens törzsek a 9V, 14, 19F szerotípusokba tartoztak. Következtetés: Az otopatogén S. pneumoniae törzsek szerotípus-megoszlása a hét szerotípus ellen védelmet adó konjugált pneumococcusvakcináció szempontjából az egyéb régiókban megismerteknek megfelel. Ennek alapján az oltás hatása az otitis media előfordulására a külföldi tanulmányokban igazoltakhoz hasonló lehet majd Magyarországon is.

Temporal relationships between colds, upper respiratory viruses detected by polymerase chain reaction, and otitis media in young children followed through a typical cold season

INTRODUCTION

Otitis media is a frequent complication of a viral upper respiratory tract infection, and the reported co-incidence of those diseases increases with assay sensitivity and sampling density. We determined the incidence of otitis-media complications in young children when referenced to cold-like illnesses and to concurrent virus recovery from the nasopharynx.

METHODS

A total of 60 children from 24 families were followed from October 2003 through April 30, 2004, by daily parental recording of illness signs, weekly pneumatic otoscopic examinations, and periodic polymerase chain reaction assay of collected nasal fluids for common viruses.

RESULTS

One hundred ninety-nine cold-like illnesses were observed, but a sample for virus assay was not collected concurrent with 71 episodes. Of the remainder, 73% of cold-like illnesses were temporally related to recovery of 1 or a combination of the assayed viruses, with rhinovirus predominating. For non-cold-like illness periods, 54 (18%) of 297 assays were positive for virus, and the virus frequency distribution was similar to that for cold-like illnesses. There were 93 diagnosed otitis-media episodes; 65 (70%) of these occurred during a cold-like illness. For the 79 otitis-media episodes with available nasal samples, 61 (77%) were associated with a positive virus result. In this population, the otitis-media complication rate for a cold-like illness was 33%.

CONCLUSIONS

A cold-like illness was not a prerequisite for polymerase chain reaction detection of viruses in the nose and nasopharynx of young children. Viral detection by polymerase chain reaction in the absence of a cold-like illness is associated with complications in some subjects. Otitis media is a complication of viral infection both with and without concurrent cold-like illnesses, thus downwardly biasing coincidence estimates that use cold-based illnesses as the denominator.

A high prevalence of new onset otitis media during parent diagnosed common colds

INTRODUCTION

Past studies suggest that the majority of new otitis media (OM) diagnoses is a complication of a colds/flu. A prospective format was used to determine the coincidence of otitis media and parent diagnosed cold/flu episodes in young children followed over a typical cold/flu season.

METHODS

Eighteen families with children aged 1-8 years were followed from October 1 to April 30 using parent-completed daily diaries focused on cold/flu signs and weekly examinations using pneumatic otoscopy for diagnosis of the presence/absence of otitis media.

RESULTS

Overall, 108 cold episodes were documented in 36 enrolled children with 20 colds (19%) occurring during a pre-existing OM episode and 40 colds (37%) complicated by a new OM episode. Conversely, there were 82 new OM episodes, 40 (49%) were associated with a cold in the individual child and 18 (22%) with a concurrent cold in a family member. The median duration of the OM episodes was approximately 2 weeks but this was longer for OM episodes where earache was reported.

CONCLUSION

The results confirm past observation relating new OM episodes to a concurrent cold/flu but show these episodes to usually be of short duration. Two sources of potential bias were identified for point prevalence study formats: the presence of a pre-existing OM for a new onset cold/flu and the possibility of subclinical colds in patients with new OM episodes. These biases reinforce the need for longitudinal study formats to address this important relationship.

Prevention of otitis media caused by viral upper respiratory tract infection: vaccines, antivirals, and other approaches

Otitis media (OM) imposes significant morbidity on the pediatric age group and a large financial burden on the general population. Because standard medical treatments are not highly efficacious in resolving the accompanying middle ear (ME) inflammation, a goal of current research is OM prevention. Past studies show that new episodes of OM are usually a complication of viral upper respiratory infection (vURI), and therefore, a rational approach to achieving that goal is to develop intervention strategies that target vURI-associated OM. However, past experiences with antibiotics show that, in the absence of well-defined treatment protocols that maximize expected efficacy, the adoption of prophylactic or active treatments for OM can have negative consequences for the patient and for the general population. In this review, we discuss the hypothesized mechanisms by which a vURI is translated into an acute OM episode and describe different strategies for aborting that process. Limitations to deployment of each strategy are outlined.

Immunologic aspects of otitis media

The middle ear cleft is a modified gas pocket which functions normally when the gas contents are regulated by a normal eustachian tube, resulting in equalization of middle ear pressure to that of the environment. The most important regulator of this middle ear pressure is the eustachian tube, a critical passageway from the nasopharynx into the middle ear. Any alteration of eustachian tube mucociliary function caused by virus, allergy, pollutants, or alteration of the normal homeostasis of the nasopharynx will result in eustachian tube obstruction. This, in turn, leads to underventilation of the middle ear, and transudation of fluid. If bacteria or virus or viral-bacterial interaction leads to infectious disease of the middle ear, an immune response is produced as a result of the inflammatory response, allowing lymphocytes and antigen-presenting cells to enter into the middle-ear mucosa. This article summarizes the immunologic reactivity in the middle ear following a viral-bacterial inflammatory reaction in the middle-ear mucosa. Although secretory IgA is critical for protection of the nasopharynx, its function in the middle ear has still not been resolved. The evidence strongly suggests that IgG1 and IgG3 subclasses are responsible for eradication of middle ear pathogens. Finally, a review of alternative approaches to the prevention of otitis media is briefly discussed in this critical period of emergence of resistant bacteria to available antibiotics.

Vaccination and otitis media

Acute otitis media (AOM) caused by Streptococcus pneumoniae, Haemophilus influenzae or Moraxella catarrhalis may induce specific systemic and/or local immune responses, which may protect from otitis media caused by the same bacteria. However, earlier clinical trials with pneumococcal capsular polysaccharide vaccines have not been successful in preventing AOM. Recently developed pneumococcal polysaccharide-protein conjugates proved immunogenic even in infants, and a heptavalent pneumococcal CRM 197 conjugate vaccine gave a 57% reduction in the number of pneumococcal AOM episodes caused by the vaccine serotypes in infants in Finland. H. influenzae causing AOM is noncapsulated, and like M. catarrhalis, calls for another kind of vaccine development. Suitable vaccine candidates are not yet available but are under development and being tested for immunogenicity and safety. In some trials influenza vaccines have shown protection from AOM during respective viral epidemics. Passive immunoprophylaxis might be an important alternative for immunocompromised children, although this approach has not been successful so far. Mucosal immunization and the advent of DNA and gene technology will open new interesting prospects in the future.