Survey of Nasopharyngeal Bacteria in Infant Outpatients

Abstract

The nasopharyngeal flora is generally thought to be a major reservoir for bacterial pathogens of respiratory tract infections in children. We surveyed the bacterial flora in the nasopharynx of 261 outpatients aged 0 to 6 yeas who visited the Department of Otorhinolaryngology and/or Pediatrics from 2005 through 2010. We obtained 118 Haemophilus influenzae (H. influenzae) isolates, 116 Streptococcus pneumoniae (S. pneumoniae) isolates, 44 Staphylococcus aureus (S. aureus) isolates, and 40 Moraxella catarrhalis isolates, and analyzed them by antibiotic susceptibility testing. The overall carriage rates of the H. influenzae strains and S. pneumoniae strains were 45.2% (118/261) and 44.4% (116/261), respectively. The percentages of ampicillin-resistant H. influenzae strains, penicillin-resistant S. pneumoniae strains and methicillin-resistant S. aureus were 80.5% (95/118), 55.2% (64/116) and 40.9% (18/44), respectively. The H. influenzae strain was susceptible to cefditren pivoxil, minocycline, and levofloxacin, while the S. pneumoniae strain was susceptible to cefditren pivoxil, cefotaxime sodium, and panipenem/betamipron. The percentage of ampicillin-resistant H. influenzae strains was invariably high in all years. On the other hand, the percentage of penicillin-resistant S. pneumoniae strains was highest in 2008, and gradually decreased after that. The recovery of susceptibility to penicillin in clinical isolates of S. pneumoniae may reflect recent enlightenment in the appropriate use of antimicrobial drugs.