We investigated the antimicrobial activity of several drugs against 131 extended-spectrum 𝛽-lactamase (ESBL) positive clinical isolates Gifu and Aichi prefecture from 2007 to 2011. Meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC₅₀ at 0.0313𝜇g/mL. MEPM gave the lowest MIC₉₀ at 0.0625𝜇g/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 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 176.6%), 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; 0.0625𝜇g/mL for garenoxacin, 0.125𝜇g/mL for panipenem, 0.25𝜇g/mL for imipenem, doripenem, tosufloxacin, 0.5𝜇g/mL for cefditoren, meropenem, moxifloxacin, 1𝜇g/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene, ceftriaxone, 2𝜇g/mL for benzylpenicillin, piperacillin, tazobactam/piperacillin, pazufloxacin, levofloxacin, 4𝜇g/mL for cefdinir, flomoxef, 16𝜇g/mL for minocycline, >64𝜇g/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 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 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. pygones. One hundred and nineteen clinical isolates of S. pyogenes isolated pharynx were tested to sitafloxacin and seven other agents in the susceptibility testing. The time-kill studies were conducted with five strains of S. pygones. 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 does for adult patients with S. pyogenes infections. We found the rank order of antimicrobial activity against S. pyogenes isolates was: cefcapene (MIC₉₀ 0.015𝜇g/mL) >amoxicillin (0.03𝜇g/mL) >sitafloxacin (0.12𝜇g/mL) >garenoxacin (0.25𝜇g/mL) >levofloxacin (4𝜇g/mL) >minocycline (16𝜇g/mL). Macrolide-resistant isolates accounted for 72 (60.5%), resulting in clarithromycin and azithromycin MIC₉₀s of >32 and >128𝜇g/mL, respectively. Sitafloxacin exhibited the most rapid bactericidal activity (≥3 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 6h. Amoxicillin revealed no significant bactericidal activity up to 6h. Clarithromycin showed no bactericidal activity and did not inhibit growth of a clarithromycin-resitant strain.

These data indicate the potential usefulness of sitafloxacin for the treatment of S. pyogenes eradication.