The Japanese journal of antibiotics最新文献

We evaluated the in vitro activity of sitafloxacin against Japanese clinical isolates of Streptococcus pyogenes by broth microdilution susceptibility testing and time-kill studies to elucidate its eradication potential against S. pyogenes. One hundred and nineteen clinical isolates of S. pyogenes isolated from pharynx were tested to sitafloxacin and seven other agents in the susceptibility testing. The time-kill studies were conducted with five strains, one of which was resistant to clarithromycin, one resistant to levofloxacin and one type strain of S. pyogenes. In the time-kill studies, sitafloxacin, garenoxacin, amoxicillin and clarithromycin were assessed at static concentrations of their respective peak concentrations in plasma (C(max)) when administered as oral single doses for adult patients with S. pyogenes infections. We found the rank order of antimicrobial activity against S. pyogenes isolates was: cefcapene (MIC90, 0.015 microg/mL) > amoxicillin (0.03 microg/mL) > sitafloxacin (0.12 microg/mL) > garenoxacin (0.25 microg/mL) > levofloxacin (4 microg/mL) > minocycline (16 microg/mL). Macrolide-resistant isolates accounted for 72 (60.5%), resulting in clarithromycin and azithromycin MIC90s of > 32 and > 128 microg/mL, respectively. Sitafloxacin exhibited the most rapid bactericidal activity (> or = log reduction from the initial inoculum) within 2h against all tested strains, including even one levofloxacin-resistant strain. For garenoxacin, bactericidal activity was achieved between 2 and 6 h. Amoxicillin revealed no significant bactericidal activity up to 6 h. Clarithromycin showed no bactericidal activity and did not inhibit growth of a clarithromycin-resistant strain. These data indicate the potential usefulness of sitafloxacin for the treatment of S. pyogenes eradication.

We investigated genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, the serotypes and the susceptibility to antibacterial agents against 258 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between January 2010 and March 2011. These results were compared with those against 377 strains of S. pneumoniae isolated in 2008-2009. The number of genotype penicillin-susceptible S. pneumoniae (gPSSP) with 3 normal PBP genes, genotype penicillin-intermediate S. pneumoniae (gPISP) with 1 or 2 normal PBP genes and genotype penicillin-resistant S. pneumoniae (gPRSP) with 3 abnormal genes was 11 (4.3%), 135 (52.3%) and 112 (43.4%) strains, respectively. The isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 17 (6.6%), 65 (25.2%), 143 (55.4%) and 33 (12.8%). The prevalent pneumococcal serotypes isolated from children were type 19F (18.2%), following by type 6A and 15 (11.7%). The potential coverage of pneumococcal conjugate vaccine (PCV7) was 43.8%. The prevalent pneumococcal serotypes isolated from adults were high in order of type 19F (12.8%), type 6A, 3 and 11 (10.3%), excepting non-typable strains (17.9%), and from elderly persons were type 6B (23.2%) and type 3 (13.4%). The MIC90 of each antibacterial agents was as follows; 0.0625 microg/mL for garenoxacin, 0.125 microg/mL for panipenem, 0.25 microg/mL for imipenem, doripenem, tosufloxacin, 0.5 microg/mL for cefditoren, meropenem, moxifloxacin, 1 microg/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene, ceftriaxone, 2 microg/mL for benzylpenicillin, piperacillin, tazobactam/ piperacillin, pazufloxacin, levofloxacin, 4 microg/mL for cefdinir, flomoxef, 16 microg/mL for minocycline, > 64 microg/mL for clarithromycin, azithromycin and these MIC90s were about the same as those in 2008-2009.

Moxifloxacin (MFLX) is a respiratory quinolone, and is effective against not only Gram-positive and negative bacteria but also anaerobes. There has been no prospective studies evaluating the efficacy and safety of MFLX in patients with nursing and healthcare-associated pneumonia (NHCAP). Therefore, we assessed the efficacy and safety of MFLX in patients with NHCAP. NHCAP patients with mild and moderate severity assessed by the A-DROP system in community-acquired pneumonia guideline proposed by Japan Respiratory Society visited our hospitals from April 2011 to March 2012. Clinical symptoms, chest X-ray films and/or computed tomography, peripheral white and red blood cell and platelet counts, serum CRP, AST, ALT, BUN, creatinine were evaluated. Forty patients were eventually evaluated, and average age was 74.1 years old, male/female were 21/19, 92.5% (37/40) of them had one or more comorbidities. Median duration of MFLX administration was 7.1 days (4-15 days). The efficacy of MFLX in all patients was 87.5% (35/40). The efficacies in each age group were 87.9% (aged over 65 years old), 85.7% (aged under 64 years old), and in each pneumonia severity group by the A-DROP system were 91.7% (mild), 85.7% (moderate). Diarrhea and swelling of the breast were observed in one patient (2.5%) after starting MFLX administration. Mild elevated transaminases were observed in three patients (7.5%), and mild renal dysfunction was observed in two patients (5.0%). All abnormally increased levels of transaminases and serum creatinine were recovered after a cessation of MFLX. MFLX is effective and safe in patients with NHCAP.

We investigated the antimicrobial activity of several drugs against 131 extended-spectrum beta-lactamase (ESBL) positive clinical isolates in Gifu and Aichi prefecture from 2007 to 2011. Meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC50 at 0.0313 microg/mL. MEPM gave the lowest MIC90 at 0.0625 microg/mL. According to the Clinical and Laboratory Standards Institute breakpoints, the susceptible rates of carbapenems, tazobactam/piperacillin (TAZ/PIPC) and cefmetazole (CMZ) were higher than 90%. The susceptible rates of MEPM, DRPM, imipenem (IPM), TAZ/PIPC and CMZ were 98.5%, 98.5%, 94.7%, 94.7% and 92.4%. We used the PCR method and identified the molecular types of the ESBL positive isolates. Seventy-two strains had CTX-M-9 group gene and CTX-M-9 group gene is the most frequently detected. Against the CTX-M-9 group gene harboring strains which were the most common in our investigation, the susceptible rates of TAZ/PIPC, MEPM, DRPM and IPM were 100%. It is suggested that not only carbapenems but also TAZ/PIPC and CMZ are useful against infections caused by ESBL positive isolates.

We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance, the results should be reported by stratifying with patient status, and type of specimens that the strain was isolated from and that regional surveillance should be useful with such stratification to establish antibiograms for empirical antimicrobial choice.

Case report: Bacterial meningitis is a rare complication of adenotonsillectomy. We present a case of meningitis due to nontypeable Haemophilus influenzae and Streptococcus pneumoniae after adenotonsillectomy. Pulsed-field gel electrophoresis patterns indicated that the oral cavity was the source of H. influenzae and S. pneumoniae isolated from the cerebrospinal fluid. BLOOD CULTURE STUDY: As bacteremia is thought to be one of the etiologies of meningitis, we prospectively investigated the rate of bacteremia as a complication of adenotonsillectomy. Of the 46 patients included in the study, mean age of five years old, 11 (24%) had positive blood cultures during the operation. H. influenzae was the commonest organism grown (seven cultures), three of seven produced beta-lactamase, followed by S. pneumoniae (one culture), H. parainfluenzae (one culture), Peptostreptococcus micros (one culture), and Veillonella spp. (one culture). The bacteria were composed of tonsil or adenoid surface cultures in eight of 11 patients (73%).

Conclusions: We present a rare case of meningitis complicating a adenotonsillectomy procedure, in a three years old boy. Meningitis is a rare complication of adenotonsillectomy, but bacteremia which may lead to meningitis occurs frequently, as the results.

The population pharmacokinetics on tazobactam/piperacillin (TAZ/PIPC; 1:8, 4.5 g x 3) was analyzed in Japanese patients with community-acquired pneumonia using the Nonlinear Mixed Effect Model version VI. Analysis by the one-compartment model yielded the following results for PIPC: total clearance (CL) = 8.22+(Ccr-71.4) x 0.0561 (L/hr), distribution volume (Vd) = 13.7 (L). The pharmacokinetic parameters for TAZ were: CL = 8.67 + (Ccr-71.4) x 0.0682 (L/hr), Vd = 14.4 (L). Of the pharmacokinetic parameters of PIPC, CL included Ccr as a variation factor, whereas the Vd included no variation factor. Because PIPC is excreted into the urine in the unchanged form, its pharmacokinetic factors seem to reflect the renal function status. In this study of patients with community-acquired pneumonia, the mean Vd per body weight was 0.26 L/kg, and the results suggested an increase of the Vd in patients with community-acquired pneumonia as compared with the value in healthy adults.