Impact of antimicrobial therapy on nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis in children with respiratory tract infections.
We conducted a multicenter prospective study to document changes in nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis during antibiotic therapy. A cohort of 629 children with respiratory tract infections underwent nasopharyngeal sampling before and after antibiotic treatment. Susceptibility testing, serotyping, arbitrarily primed polymerase chain reaction, and pulsed-field gel electrophoresis were used to compare pretreatment and posttreatment strains of S. pneumoniae. A significant decrease in carriage of all 3 species (especially S. pneumoniae and B. catarrhalis) was recorded. The increase in the proportion of penicillin-resistant pneumococci (PRP; 66% vs. 44%) was due to the decreased carriage of penicillin-susceptible pneumococci (71 of 629 vs. 176 of 629). The risk of PRP carriage in a given child did not increase. None of the children was found to harbor genetically related strains with increased minimum inhibitory concentrations. Given the multiple resistance of PRP, beta-lactam antibiotic therapy also increased the incidence of macrolide-resistant strains, whereas macrolides selected both macrolide- and penicillin-resistant strains.
Varon
E
E
Laboratoire de Recherche Moleculaire sur les Antibiotiques, Université Paris VI, Paris, France.
Levy
C
C
De La Rocque
F
F
Boucherat
M
M
Deforche
D
D
Podglajen
I
I
Navel
M
M
Cohen
R
R
D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D002353:Carrier State / Q000188:drug therapy* / Q000382:microbiology; D003470:Culture Media; D016521:Electrophoresis, Gel, Pulsed-Field; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D006192:Haemophilus Infections / Q000188:drug therapy / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D009305:Nasopharynx / Q000187:drug effects / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000382:microbiology; D011446:Prospective Studies; D019105:Random Amplified Polymorphic DNA Technique; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D003470:Culture Media