Effects of amoxicillin/clavulanate or azithromycin on nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae in children with acute otitis media.
The effect of antibiotic therapy on nasopharyngeal colonization by Streptococcus pneumoniae and Haemophilus influenzae was evaluated in children diagnosed with acute otitis media. Children were randomly assigned to receive either amoxicillin/clavulanate or azithromycin therapy, and nasopharyngeal swabs were obtained for culture before and after starting therapy. Amoxicillin/clavulanate therapy eradicated or suppressed all strains of S. pneumoniae susceptible to penicillin, 75% of strains with intermediate resistance, and 40% of strains resistant to penicillin. Azithromycin therapy cleared two-thirds of azithromycin-susceptible strains of S. pneumoniae but none of azithromycin-nonsusceptible strains. Selection for antibiotic-resistant strains in individual children was not observed in children who received amoxicillin/clavulanate therapy but was observed in 2 children who received azithromycin therapy. Carriage of H. influenzae was also reduced by antimicrobial therapy but more so by amoxicillin/clavulanate. Antibiotic therapy does not directly increase the number of resistant strains in the population but, by eradicating susceptible strains, allows greater opportunity for carriage and spread of resistant strains.
Ghaffar
F
F
Dept. of Pediatrics, Division of Infectious Disease, University of Texas Southwestern Medical Center, Dallas, TX 75235-9063, USA. fghaff@mednet.swmed.edu
Muniz
L S
LS
Katz
K
K
Reynolds
J
J
Smith
J L
JL
Davis
P
P
Friedland
I R
IR
McCracken
G H
GH
D000208:Acute Disease; D000658:Amoxicillin / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017963:Azithromycin / Q000627:therapeutic use*; D002353:Carrier State / Q000188:drug therapy / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D019818:Clavulanic Acid / Q000627:therapeutic use*; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D006192:Haemophilus Infections / Q000188:drug therapy / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D010033:Otitis Media / Q000188:drug therapy* / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D019818:Clavulanic Acid; D000658:Amoxicillin; D017963:Azithromycin