title: Causative pathogens, antibiotic resistance and therapeutic considerations in acute otitis media.
abstract: Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis are the most frequently isolated pathogens in patients with acute otitis media (AOM). Other potential causative pathogens include Streptococcus pyogenes in older children and Chlamydia pneumoniae in younger children. The recent emergence of penicillin-resistant S. pneumoniae and the increasing frequency of beta-lactamase-producing strains of M. catarrhalis and H. influenzae are creating concerns regarding the use of amoxicillin as traditional first line empiric therapy for AOM in younger children. Both the in vitro antibiotic activity against these more resistant causative pathogens and the antibiotic concentrations achieved in middle ear fluid must be considered when selecting antibiotics for treatment of refractory AOM. The newer macrolides, azithromycin and clarithromycin, provide reasonable in vitro coverage against penicillin-resistant S. pneumoniae and beta-lactamase-producing H. influenzae, although azithromycin is more active against the latter. Both drugs also achieve notably higher, sustained concentrations in middle ear fluid than do beta-lactam antibiotics. Thus the newer macrolides represent important new rational alternatives for the management of AOM.
authors.affiliation: Kentucky Pediatric Research, Bardstown 40004, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Block
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017963:Azithromycin / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000627:therapeutic use*; D006192:Haemophilus Infections / Q000188:drug therapy*; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D007223:Infant; D007769:Lactams; D001936:Moraxella catarrhalis / Q000187:drug effects*; D016870:Neisseriaceae Infections / Q000188:drug therapy*; D010033:Otitis Media / Q000188:drug therapy* / Q000382:microbiology*; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use*; D013290:Streptococcal Infections / Q000188:drug therapy*; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D007769:Lactams; D010406:Penicillins; D017963:Azithromycin; D017291:Clarithromycin