Current trends in the antibiotic therapy of uncomplicated Acute Otitis Media in children: concluding remarks

Abstract

Acute otitis media (AOM) is a very common condition, but its management remains difficult. Accurate recognition of the disease represents the first dilemma. None of the symptoms are specific. Even the red tympanic membrane can be caused by the child’s crying or the viral upper respiratory infection that usually accompanies the disease. So AOM is commonly overdiagnosed. Since the first line antibiotic therapy is considered as safe and well tolerated, an antibiotic is often prescribed, even when the diagnosis is uncertain, for the satisfaction of both the parents and the physician. A famous Dutch study [l] reported no difference in outcome after antibiotics, myringotomy, antibiotics combined with myringotomy, or placebo. Hence an approach consists to restrict antimicrobial therapy to children continuing to have symptoms after a period of 24-72 hours of observation. A spontaneous resolution of acute symptoms occurs in the majority of the cases, but the calculations done here by Grenier [2] suggest that this “masterful inactivity” may cost more than an antibiotic therapy initiated as soon as the diagnosis is suspected because of a greater expense for medical visits. Once the decision to start antibiotic treatment has been taken, the choice of the antibiotic therapy comes next, and it is clear that it should be addressed against the main pathogens involved. The bacterial aetiology of AOM is well-known: three organisms represent up to 80-90% of all causes, Streptococcus pneumoniae, Haemophilus influenzae and to a lesser degree, Moraxella catarrhalis [3]. In most cases, microbiology testing is not available, but a few clinical clues exist which can somewhat orientate the clinician toward a given pathogen. So the rare otitis conjunctivitis syndrome is indicative of an H. injuenzae aetiology in 75% of the cases [4] and a temperature above 38,5” is associated to the pneumococcal aetiology in SO% of the cases [S]. Some risk factors of nasopharyngeal carriage with penicillin-resistant S. pneumoniae have been identified: age less than eighteen months, attendance in day care centers, home in urbanized areas, antibiotic therapy in the three last months, and previous failures of otitis media [6]. Keeping in mind the spontaneous clearance of the different offending agents (80%, 56% and 20%, respectively for S. pneumoniae, H . influenzae and M. catarrhalis [7]) and the different morbidity and rates of potential complications, it is clearly of paramount importance to offer adequate coverage for the possible pneumococcal aetiology. The prevalence of local antibiotic resistance is, from this point of view, crucial if a rational choice of the empiric treatment is to be made. In this regard, it is important to know the current prevalence of penicillin-resistant pneumococci and of p-lactamase producing H . inzuenzae. Penicillin-resistance in pneumococci affects to a different degree all p-lactams. It is not due to P-lactamase production and can be overcome by increasing the concentration of the antibiotic at the site of infection. It is also important to consider the frequency of resistance to other agents. Penicillin-resistant pneumococci are often resistant to macrolides and cotrimoxazole; in non-typable Haemophilus influenzae, resistance to cotrimoxazole has been reported, in many areas of the world [8]. From these considerations it appears that the use of p-lactams active in vivo against these resistant organisms will be effective with dosages that will produce concentrations above the MIC of the offending strain in the case of S. pneumoniae and could resist the (3-lactamase hydrolysis in the case of H . injuenzae. The absence of comparative clinical trials with well defined end-points including bacterial eradication from the middle ear for the currently used antimicrobials, forces us to rely, when choosing between the different therapeutic options, on microbiological and pharmacological