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Microbiology of acute otitis media with particular reference to the feasibility of pneumococcal immunization
Abstract:
Middle-ear fluid was aspirated in 103 episodes of acute otitis media occurring in 100 South Australian children aged from four months to 14 years in 1977, and in 1978. Bacteria were cultured from the middle-ear fluid in 66% of cases, and viruses were grown in three cases in conjunction with bacteria. The bacteria grown were pneumococci in 30 cases (29%), Haemophilus influenzae in 26 cases (25%), beta-haemolytic streptococci in 12 cases (12%) and Neisseria spp. in six cases (6%). Pneumococci and H. influenzae were cultured from children of all ages, whereas beta-haemolytic streptococci were more frequently isolated in children aged five years and older. Countercurrent immunoelectrophoresis yielded positive results in 35% of culture-positive pneumococcal infections and gave additionally the positive reaction for pneumococci in two cases where culture produced negative results. The pneumococci which were isolated belonged to 12 serotypes; 26 of the 30 isolates were serotypes for which pneumococcal vaccines are currently available. There were appreciable differences in the distribution of serotypes from that encountered in a study of nasal carriage amongst healthy schoolchildren living in the same district.
Insights
Bacterial infections, including pneumococci and Haemophilus influenzae, are common causes of acute otitis media in South Australian children. Many isolated pneumococci serotypes are covered by current vaccines.
Area of Science:
- Pediatrics
- Microbiology
- Infectious Diseases
Background:
- Acute otitis media (AOM) is a common childhood infection.
- Identifying causative pathogens is crucial for effective treatment and prevention.
Purpose of the Study:
- To investigate the bacterial and viral pathogens causing AOM in South Australian children.
- To analyze the distribution of bacterial species and pneumococcal serotypes.
Main Methods:
- Middle-ear fluid samples were collected from 103 episodes of AOM in children aged 4 months to 14 years.
- Bacterial and viral cultures were performed.
- Countercurrent immunoelectrophoresis (CIE) was used for pneumococcal detection.
- Pneumococcal serotyping was conducted.
Main Results:
- Bacteria were cultured in 66% of AOM cases; viruses were found in 3%.
- The most common bacteria were Streptococcus pneumoniae (29%), Haemophilus influenzae (25%), and beta-hemolytic streptococci (12%).
- Pneumococci and H. influenzae were found across all age groups, while beta-hemolytic streptococci were more prevalent in older children.
- CIE detected pneumococci in 35% of culture-positive cases and identified 2 additional positive cases.
- 26 of 30 S. pneumoniae isolates (87%) belonged to serotypes covered by current vaccines.
Conclusions:
- S. pneumoniae and H. influenzae are key bacterial pathogens in childhood AOM in this region.
- The prevalence of vaccine-preventable pneumococcal serotypes suggests potential impact of vaccination programs.
- Serotype distribution differs from nasal carriage studies, highlighting the importance of direct infection site sampling.