cefditoren and tebipenem

Topics: Acute Disease; Ampicillin; Anti-Bacterial Agents; beta-Lactam Resistance; Carbapenems; Cephalosporins; Child, Preschool; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Haemophilus Infections; Haemophilus influenzae; Humans; Infant; Japan; Microbial Sensitivity Tests; Multilocus Sequence Typing; Naphthyridines; Otitis Media; Pneumococcal Vaccines; Quinolones; Streptococcus pneumoniae; Vaccines, Conjugate

Topics: Anti-Bacterial Agents; Bacteria; Bacterial Infections; Carbapenems; Cephalosporins; China; Community-Acquired Infections; Humans; Microbial Sensitivity Tests; Respiratory Tract Infections

Morphological changes in penicillin-resistant Streptococcus pneumoniae (PRSP) and beta-lactamase-nonproducing, ampicillin-resistant Haemophilus influenzae (BLNAR) after exposure to oral antibacterial agents could be observed over time under a phase-contrast microscope. Morphological changes in BLNAR were also observed using a scanning electron microscope. The organisms used in this study were ME19F strain identified as genotypic(g) gPRSP (serotype: 19F) and JPH002 strain identified as gBLNAR (serotype: b). The antibacterial agents used were amoxicillin (AMPC), cefditoren (CDTR), tebipenem (TBPM), and tosufloxacin (TFLX). The concentration of each antibacterial agent to which the bacteria were exposed was set at the blood level one hour after Cmax when administered to children at the usual dose. Bacteriolysis of gPRSP cells started after exposure of only 20minutes to TBPM, and 90% of the cells were lysed within 2 hours. A high bactericidal action of TBPM on gPRSP was supported by these findings. When gBLNAR was exposed to AMPC and TBPM, lysis from spheroplasts and cells with vacuoles were sometimes observed. In contrast, after gBLNAR was exposed to CDTR, lysis occurred after marked filamentation in the cells, but after exposure to TFLX, cells deduced to be killed after mild filamentation without lysis. Time-dependent morphological changes that reflect the differences in bactericidal activity and PBP affinity among beta-lactams provide beneficial information to select antibacterial agents.

Topics: Amoxicillin; Ampicillin Resistance; Anti-Bacterial Agents; Bacteriolysis; beta-Lactamases; Carbapenems; Cephalosporins; Child; Dose-Response Relationship, Drug; Fluoroquinolones; Haemophilus Infections; Haemophilus influenzae; Humans; Microscopy, Phase-Contrast; Naphthyridines; Penicillin Resistance; Pneumococcal Infections; Streptococcus pneumoniae; Time Factors

Horizontal transfer of the mutated ftsI gene from beta-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae to a susceptible strain was examined in vitro under selection with nine oral beta-lactams (ampicillin, amoxicillin, cefprozil, cefuroxime, cefpodoxime, cefdinir, cefcapene, cefditoren, and tebipenem). Compared to the penicillins and the carbapenem, the cephalosporins showed a wide selection window for the genetic transfer.

Topics: Ampicillin; Bacterial Proteins; beta-Lactams; Carbapenems; Cefdinir; Cefprozil; Cephalosporins; Gene Transfer, Horizontal; Haemophilus influenzae; Mutation; Penicillin-Binding Proteins

Fifty isolates of Streptococcus pneumoniae and 42 isolates of Haemophilus influenzae were isolated from the blood of children admitted to pediatric wards of hospitals in subprefucture between January 1998 and December 2005. The susceptibilities were measured by a microbroth dilution method using a standard broth and a broth containing 4.5% albumin. Against S. pneumoniae, penicillin G, ampicillin, cefotaxime, ceftriaxone, panipenem, meropenem, vancomycin, cefditoren, cefcapene, cefteram, faropenem and tebipenem were used and against H. influenzae, ampicillin, piperacillin, cefotaxime, ceftriaxone, panipenem, meropenem, clavulanic acid/ amoxicillin, cefditoren, cefcapene, cefteram, faropenem and tebipenem were used. Against S. pneumoniae, tebipenem was the highest antimicrobial activity in oral antibiotics (MIC90; < or = 0.06 microg/ml) and panipenem showed the highest activity for intravenous antibiotics (MIC90; < or = 0.12 microg/ml). Against H. influenzae, cefditoren was the highest activity for oral antibiotics (MIC90; < or = 0.06 microg/ml) and meropenem showed the highest activity for intravenous antibiotics (MIC90; < or = 50.06 microg/ml). The MIC90s measured by albumin containing broth were higher than those measured by standard broth. Protein binding rates of ceftriaxone, cefditoren, and faropenem were greater than 90%, and the MIC90 of these antibiotics measured by albumin addition methods were over 4-fold higher than those measured by standard methods.

Topics: Administration, Oral; Anti-Bacterial Agents; Carbapenems; Cephalosporins; Child; Haemophilus influenzae; Humans; Injections, Intravenous; Meropenem; Microbial Sensitivity Tests; Protein Binding; Streptococcus pneumoniae; Thienamycins