Antibacterial activity for clinical isolates from pediatric patients of clavulanic acid/amoxicillin (1:14) ―Outcomes of special drug use investigation on antibacterial activity (annual changes)

As a special drug use investigation, we monitored and assessed trends in antibacterial activity of clavulanic acid/amoxicillin (1:14) (hereafter, “CVA/AMPC (1:14)”) and other antimicrobial agents for clinical isolates from pediatric patients with otitis media or respiratory, skin, and urinary tract infections.Against Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis isolated and identifies form otorrhea, epipharynx and rhinorrhea of pediatric patients with otitis media, the MIC90s of CVA/AMPC (1:14) in five years between 2006-2010 were 1μg/mL for S. pneumoniae and 8μg/mL for H. influenzae and 0.25-0.5μg/mL for M. catarrhalis. The changes of MIC90s of CVA/AMPC (1:14) for penicillin-resistant S. pneumoniae (PRSP) and β-lactamase non-producing H. influenzae were two times, and no decrease in drug susceptibility was found in the period of the present investigation. In addition, the MIC changes of other antimicrobial agents for these three organisms were approximately two to four times as well.Against organisms isolated and identified from pus, sputum, pharynx, skin and urine of pediatric patients with respiratory, skin, and urinary tract infections, the MIC90s of CVA/AMPC (1:14) in four years between 2008-2011 were 1μg/mL for S. pneumoniae, ≤0.06μg/mL for penicillin susceptible S. pneumoniae (PSSP) without any change, 0.5-1μg/mL for penicillin intermediate resistant S. pneumoniae (PISP) with a twofold change and 1μg/mL for PRSP with no change. The MIC90s of CVA/AMPC (1:14) were 2-8μg/mL for S. aureus with a fourfold change, 2μg/mL for methicillin-sensitive S. aureus without any change, 4-8μg/mL for H. influenzae with a twofold change. Against β-lactamase non-producing H. influenzae, MIC90s of CVA/AMPC (1:14) were 1μg/mL for β-lactamase negative ampicillin susceptible (BLNAS), 8μg/mL for β-lactamase negative ampicillin resistant (BLNAR), showing no change. Neither Streptococcus pyogenes or Klebsiella pneumoniae demonstrated any change and M. catarrhalis and Escherichia coli showed twofold changes of MIC90s of CVA/AMPC (1:14).In the present investigation conducted to monitor annual changes in antibacterial activity intended for pediatric patients with otitis media or other infections, there was no significant change in antibacterial activity of CVA/AMPC (1:14).