Streptococcus pneumoniae (
S. pneumoniae) and
Haemophilus influenzae (
H. influenzae) are the most common pathogens in upper respiratory infections. Increasing antimicrobial resistance of such bacteria, particularly in infants, give rise to a stubborn therapeutic problem. We surveyed these bacteria in the nasopharynx of infant patients with upper respiratory infections. We isolated 160 strains of
S. pneumoniae and 162 of
H. influenzae, from 234 infants (0-6 years with an average age of 1.6 years) from 2000 through 2004, and subjected them to antimicrobial susceptibility tests by broth microdilution. Penicillin-resistant
S. pneumoniae (PRSP) and β-lactamase-negative ampicillin-resistant
H. influenzae (BLNAR) were higher in 2004 (20.0% and 52.2%) than in 2000 (7.5% and 30.7%).
S. pneumoniae was susceptible to panipenem/betamipron (MIC
90=0.06μg/ml) and cefditren pivoxil (MIC
90=0.5μg/ml), while
H. influenzae was susceptible to levofloxacin (MIC
90=0.12μg/ml), ceftriaxone (MIC
90=0.25μg/ml), meropenem (MIC
90=0.25μg/ml), and minocycline (MIC
90=0.5μg/ml). We next surveyed
S. pneumoniae and
H. influenzae in the nasopharynx of 188 preshoolers (0-6 years with an average age of 2.8 years) in 2004.
S. pneumoniae and
H. influenzae were detected in 81 (43.1%) and 71 (37.8%) children. PRSP was only 1.3%, but penicillin-intermediate
S. pneumoniae (PISP) was 39.5%, indicating potential prevalence of resistant
S. pneumoniae. The rate of BLNAR (39.4%) also showed a high prevalence of resistant
H. influenzae among preschoolers. We studied the postoperative change of resistant bacteria in the nasopharynx of 6 children (2-6 years with an average age of 3.5 years) who underwent adenoidectomy. Resistant
S. pneumoniae and
H. influenzae disappeared in 5 patients (83%) 7 to 12 months after surgery, suggesting that adenoidectomy is a promising alternative to control of such resistant bacteria in the upper airway. Epidemiology, prophylaxis, and management of upper respiratory infections caused by resistant bacteria in infants are reviewed based on the literature.
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