In-vitro bactericidal activity of four oral antibiotics against pathogens responsible for acute otitis media in children.
This study was designed to test the in-vitro activity of four oral antibiotics against the four microorganisms most frequently isolated in acute otitis media: beta-lactamase-positive Haemophilus influenzae (N = 10), beta-lactamase-positive Moraxella catarrhalis (N = 10), penicillin-sensitive Streptococcus pneumoniae (N = 11) and methicillin-sensitive Staphylococcus aureus (N = 10), by the bactericidal curve method. Bactericidal kinetics were determined for concentrations of antibiotic equivalent to those found in the middle ear after treatment: amoxycillin-clavulanic acid (2.5 mg l-1/0.6 mg l-1 and 2.5 mg l-1/1.2 mg l-1), cefaclor (1 mg l-1), erythromycin (0.5 mg l-1) and erythromycin/sulfisoxazole (0.2/3 mg l-1). The inoculum was of 10(6) colony-forming units (cfu) ml-1. The bacterial counts were performed after 5 h and 24 h using a spiral inoculator system. The results showed that amoxycillin-clavulanic acid had rapid bactericidal activity (< 24 h) on the tested organisms at each of the doses used (reduction < or = 3 log10 cfu ml-1) which was not observed with the other antibiotics at either 5 or 24 h. Erythromycin alone or combined with sulfisoxazole had a bacteriostatic effect on Moraxella catarrhalis and Streptococcus pneumoniae but not on Haemophilus influenzae or Staphylococcus aureus. Cefaclor had no bactericidal action under these conditions.
Hôpital Robert Debré, Service de Bactériologie, Paris, France.
N
N
Lambert-Zechovsky
P
P
Mariani-Kurkdjian
C
C
Doit
F
F
Bourgeois
E
E
Bingen
D000208:Acute Disease; D000658:Amoxicillin / Q000494:pharmacology; D019980:Amoxicillin-Potassium Clavulanate Combination; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002433:Cefaclor / Q000494:pharmacology; D002675:Child, Preschool; D002969:Clavulanic Acids / Q000494:pharmacology; D015169:Colony Count, Microbial; D004359:Drug Therapy, Combination / Q000494:pharmacology; D004917:Erythromycin / Q000494:pharmacology; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006193:Haemophilus influenzae / Q000187:drug effects; D006801:Humans; D007223:Infant; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects; D010033:Otitis Media / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013444:Sulfisoxazole / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D004917:Erythromycin; D002433:Cefaclor; D013444:Sulfisoxazole; D019980:Amoxicillin-Potassium Clavulanate Combination; D000658:Amoxicillin