Microbiologic Etiology Related to Treatment

Related to an accurate diagnosis, there is a difference in the prevalence of bacterial pathogens that are isolated from ears of patients with acute otitis media compared to aspirates of otitis media with effusion. This, in turn, has an impact on the decision to recommend or not recommend antimicrobial therapy.

Pathogenic bacteria are present in approximately 70% of the middle ears of patients who have acute otitis media, and are similar in type in both children and adults.2'3 Streptococcus pneumoniae (40%), Haemophilus influenzae (25%), and Moraxella catarrhalis (12%) are the most common pathogens isolated. Group A b-hemolytic streptococcus and Staphylococcus aureus also cause this infection in both children and adults, but not as frequently as pneumococcus and H. influenzae. Respiratory viruses have been cultured from as many as 20% of acute effusions.

The percentage of H. influenzae that is b-lactamase-producing varies according to the community in the United States, but the rate is now about 25%. Currently, most, if not all strains of M. catarrhalis produce b-lactamase. The rate of isolation of multidrug-resistant S. pneumoniae is increasing in this country. At the Children's Hospital of Pittsburgh—a tertiary referral center—the rate

0 0

Post a comment