An in vitro human plasma concentration simulation model with a hollow fiber system was established and used to evaluate the bactericidal effect of levofloxacin (LVFX)500 mg q.d. in combination with meropenem (MEPM)1000 mg t.i.d. against Pseudomonas aeruginosa. Six clinical isolates of P. aeruginosa which had MEPM MICs of 2～16μg/mL, LVFX MICs of 2μg/ mL, and fractional inhibitory concentration (FIC) indices by the in vitro checkerboard method of 0.625～1 were used. In the treatment with MEPM alone, initial viable counts (10⁶～10⁷ CFU/ mL) decreased, but did not reach below the detection limit (100 CFU/mL) and the regrowth of bacteria was observed. In the treatment with LVFX alone, viable counts decreased once below the detection limit, although increased after treatment for 24 hours. On the other hand, in the treatment with LVFX-MEPM combination, more potent bactericidal effects were observed compared to LVFX or MEPM alone in all strains. Especially, in the strains with MEPM MICs of 2 and 4μg/mL, viable counts rapidly decreased below the detection limit and no regrowth was observed until 24 hours. These results suggested that LVFX-MEPM has a potential to be an effective combination against P. aeruginosa by synergistic rapid bactericidal action in clinical settings, even in the strain against which no significant synergy is confirmed by the traditional in vitro checkerboard method.

Sitafloxacin (STFX, Gracevit^® 50 mg, ¿ne granules 10%), a new quinolone antibacterial agent, was approved in January 2008, and the use-results survey was carried out over the 2 years between December 2008 and November 2010. We studied the efficacy and safety of STFX in 1,452 patients with urinary tract infections (cystitis, pyelonephritis, urethritis).

The total efficacy rate for urinary tract infections was 91.4% (1,235/1,351 patients). Efficacy rates, classified by the type of infection, were: uncomplicated cystitis 95.9% (466/486 patients), complicated cystitis 87.2% (511/586 patients), uncomplicated pyelonephritis 96.1% (49/51 patients), complicated pyelonephritis 93.5% (145/155 patients), and urethritis 87.7% (64/73 patients). Efficacy rates were 86.0% (49/57 patients) for non-responders to cephems and 77.4% (48/62 patients) for non-responders to quinolones.

The eradication rate of indicated strains was 90.5% (545/602 strains). The eradication rates of major causative bacteria were; Escherichia coli 92.7% (294/317 isolates), Enterococcus faecalis 86.0% (43/50 isolates), Pseudomonas aeruginosa 66.7% (16/24 isolates), Klebsiella pneumoniae 95.2% (20/21 isolates), and Chlamydia trachomatis 88.9% (8/9 isolates).

The incidence of adverse drug reactions (ADRs) was 2.71% (37/1,365 cases). Major ADRs were diarrhoea (0.88%, 12 cases) and hepatic function disorders (0.51%, 7 cases). A serious ADR (hepatic function abnormality) was observed in 1 case, and the hepatic function in this patient returned to normal after treatment with STFX was discontinued.

In conclusion, these results suggest that STFX is a useful antibacterial agent with an efficacy rate of 91.4% against urinary tract infections, with a minimum ef¿cacy rate of 87.2% (against complicated cystitis), and has no serious problems in its safety profile.

This study evaluated the in vitro activity of doripenem (DRPM) against 200 Streptococcus pneumoniae and 197 Haemophilus influenzae from children and adults in 2007, 50 H. influenzae type b in 2006, 20 Listeria monocytogenes in 1990–2005, 23 Neisseria meningitidis in 2007– 2009 and 83 Bordetella pertussis in 1989–2003. All strains were isolated from Japanese clinical facilities. We also investigated in vitro activity of other carbapenems (meropenem, imipenem, panipenem, biapenem), cephems (ceftriaxone, cefotaxime), ampicillin and clarithromycin. The all MICs were determined by a broth micro dilution method or an agar dilution method according to CLSI. The MIC₉₀s of DRPM against S. pneumoniae and H. influenzae from children were 0.25 ȝg/mL, 1 ȝg/mL, respectively, which were similar to strains from adults. These results suggested that antibacterial activity of DRPM is not variable by patient’s age.

DRPM also showed excellent activities against H. influenzae type b, L. monocytogenes and N. meningitidis, which cause purulent meningitis, and B. pertussis causing whooping cough more than the other carbapenems. DRPM showed superior activities against serious strains of pediatric infection diseases.

We investigated the efficacy and safety of levofloxacin (LVFX)500 mg once a day in patients with non-gonorrheal urethritis.

Men, aged 20 years or older, with urethritis symptoms, and detection of Chlamydia trachomatis(C. trachomatis) or Mycoplasma genitalium(M. genitalium) by a microbiological examination were eligible for this study. Patients were administered LVFX 500 mg, orally, once a

day and the dosage period was seven days.

We assumed 22 patients for a safety and efficacy analysis. In 22 patients, 17 patients had urethritis with C. trachomatis, 4 patients urethritis with M. genitalium, and one patient mixed infection of C. trachomatis and M. genitalium. In the clinial study, the primary endpoint was set as the bacteriological eradication rate at two to four weeks after completion of treatment. The bacterial eradication rate in the urethritis was 86.4% (19/22). The bacterial eradication rate in the urethritis with C. trachomatis, M. genitalium, and mixed infection of C. trachomatis and M. genitalium were 94.1% (16/17), 50.0% (2/4), 100% (1/1), respectively. A significant difference was not recognized among the three groups. The clinical efficacy at two to four weeks after completion of treatment was 90.9% (20/22). The clinical efficacy rates in the urethritis with C. trachomatis, M. genitalium, and mixed infection of C. trachomatis and M. genitalium were 100% (17/17), 50.0% (2/4), 100% (1/1), respectively. The efficacy rate of urethritis with M. genitalium was significantly low. No adverse drug reactions were observed. These results suggest that once-a-day levofloxacin (500 mg) is effective and safe treatment for non-gonorrheal urethritis.