Real-time PCR detection of causative microorganisms in pediatric patients with acute otitis media in clinical phase III tebipenem-pivoxil studies

We used real-time PCR, together with conventional bacterial culture, to detect bacteria and viruses and heighten the accuracy of detecting causative microorganisms in Phase III clinical trials of tebipenempivoxil (TBPM-PI), an oral carbapenem antibiotic, in pediatric patients with acute otitis media(AOM). Of 399 subjects, 224 (56.1%) showed positive results in culture and real-time PCR. In 41 (10.3 %), pbp genes mediating β-lactam. resistance of Streptococcus pneumoniae and Haemophilus influenzae were identified by conventional PCR after real-time PCR, but cultivation was negative. In 47 (11.8%), no resistance genes were identified by conventional PCR even though real-time PCR was positive. In addition, 8 subjects (2.0%) were virus-positive. Isolates determined to be causative microorganisms were S. pneumoniae, with 117 isolates in 116 subjects; H. influenzae with 112 isolates; Streptococcus pyogenes in 8 subjects; Moraxella catarrhalis with 7 isolates, and Staphylococcus aureus with 2 isolates. Bacteria showing positive results alone in real-time PCR were mostly S. pneumoniae and H. influenzae. A high correlation (γ = 0.9369 to 0.9710) between the number of bacteria in culture and Ct value of the positive reaction in real-time PCR was noted in S. pneumoniae and H. influenzae. According to AOM guidelines published in 2006, severe cases are significantly more in whom organisms were isolated (P<0.0001). We concluded that real-time PCR use in clinical studies increases the accuracy of detecting causative microorganisms.