[Antibiotic susceptibility of blood-borne Streptococcus pneumoniae and efficacy assessment of respiratory quinolones using Monte Carlo simulation].
We analyzed Streptococcus pneumoniae isolates from the bloodstream between April 2005 and February 2007. We analyzed isolates of 28 strains from medical facilities in Gifu prefecture to determine antibiotic susceptibility, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes. We also assessed the efficacy of respiratory quinolones using Monte Carlo simulation. Garenoxacin (GRNX) and moxifloxacin (MFLX) showed the lowest MIC90 value of 0.125 microg/mL, followed by MIC90 of imipenem (IPM) of 0.25 microg/mL and tosufloxacin (TFLX), MIC90 of meropenem (MEPM) and vancomycin (VCM) of 0.5 microg/mL. Twenty-two strains possessed at least one mutation in PBP-encoding genes pbp1a, pbp2x or pbp2b and seven strains possessed all three mutant alleles. Twenty-two strains possessed either of macrolide resistant genes ermB or mefA, and one strain possessed both. On efficacy assessment, we calculated the probability of target attainment for free-drug area under the curve (fAUC)/MIC ratio (fAUC/MIC). GRNX and MFLX showed a probability of 90% or more at fAUC/MIC of 30 and 125, each considered effective against Gram-positive bacteria and suppression of resistance development, furthermore, GRNX showed a probability of 89.7% at fAUC/MIC of 250.
Kawamoto
Hiroshi
H
Research Laboratories of Toyama Chemical Co., Ltd.
Nomura
Nobuhiko
N
Mitsuyama
Junichi
J
Yamaoka
Kazukiyo
K
Asano
Yuko
Y
Sawamura
Haruki
H
Suematsu
Hiroyuki
H
Teraji
Mayumi
M
Hashido
Hikonori
H
Matsukawa
Yoko
Y
Matsubara
Shigenori
S
Miyabe
Takanori
T
Mikamo
Hiroshige
H
Watanabe
Kunitomo
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001769:Blood / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024841:Fluoroquinolones / Q000493:pharmacokinetics* / Q000494:pharmacology*; D005838:Genotype; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D000077731:Meropenem; D009010:Monte Carlo Method; D009154:Mutation; D046915:Penicillin-Binding Proteins / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D013845:Thienamycins / Q000494:pharmacology*; D014640:Vancomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D046915:Penicillin-Binding Proteins; D013845:Thienamycins; D014640:Vancomycin; D015378:Imipenem; D000077731:Meropenem