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[Bacteriological study in acute otitis media]
M Le Bideau1, A Mouzard, C Chamoux
1Clinique médicale pédiatrique, centre hospitalier regional universitaire, Nantes, France.
Insights
Bacteriological studies in acute otitis media show that middle ear aspirates are often sterile after antibiotic treatment, suggesting other factors may cause persistent symptoms. Penicillin-resistant Streptococcus pneumoniae strains were identified but rarely caused clinical failure.
Area of Science:
- Pediatric infectious diseases
- Microbiology of otitis media
Background:
- Acute otitis media (AOM) is a common childhood infection.
- Bacteriological epidemiology of AOM requires ongoing investigation.
Purpose of the Study:
- To investigate the bacteriological epidemiology of acute otitis media in children.
- To assess the impact of prior antibiotic treatment on middle ear cultures.
Main Methods:
- Prospective study in a pediatric hospital emergency service.
- Inclusion of 158 children aged 6 months to 6 years with AOM.
- Tympanocentesis and middle ear fluid culture performed in 118 children, with 46 having prior antibiotic exposure.
Main Results:
- Middle ear aspirates were sterile in 35% of untreated children and 64% of those previously treated with antibiotics.
- Predominant bacteria identified were Haemophilus influenzae and Streptococcus pneumoniae.
- 59% of S. pneumoniae strains were penicillin-resistant, but only caused clinical failure in 8% of cases.
Conclusions:
- Precise aspiration techniques minimize contamination, aiding in differentiating ear canal flora from middle ear pathogens.
- A high rate of sterile middle ear aspirates post-antibiotic treatment suggests non-bacterial factors may contribute to persistent AOM symptoms.
- Awareness of penicillin-resistant S. pneumoniae is crucial for appropriate treatment adjustments.
Aim:
A prospective study on bacteriological epidemiology in acute otitis media was conducted in a pediatric hospital emergency service from January 1993 to October 1995.
Patients:
One hundred and fifty-eight children, aged 6 months to 6 years, with an acute otitis media were included. Culturing and cleansing of the ear canal and tympanocentesis for aspiration and culture of the secretions were performed in 118 children (46 of whom had received antibiotics before for 48 hours).
Main Results:
Middle ear aspirates were sterile in 35% of the children who had not received antibiotics and in 64% of those already treated. Bacteria in middle ear were predominantly Haemophilus influenzae and Streptococcus pneumoniae. Fifty-nine percent of S pneumoniae strains were penicillin-resistant; however, they were responsible for clinical failure in only 8% of cases. No Staphylococcus strains, commensal of the ear canal, could be considered as pathogenic for the middle ear.
Conclusion:
The preciseness with which secretions of middle ear are aspirated reduces the risk of contamination and comparison of ear canal and middle ear cultures allows to identify them. The high ratio of sterile middle ear aspirates after antibiotic treatment raises the question if other factors are responsible for persistent symptoms. The existence of penicillin-resistant S pneumoniae must be known to adjust treatment.