Efficacy of beta-lactam and inhibitor combinations in a diffusion chamber model in rabbits

Effect of prolonged fluconazole treatment on Candida albicans in diffusion chambers implanted into mice

Fluconazole is an azole agent with primarily fungistatic activity in standard in vitro susceptibility tests. The present study was undertaken to develop a diffusion chamber model system in mice in order to study the in vivo effects of prolonged fluconazole treatment on Candida albicans. Chambers containing 100 C. albicans yeast cells were implanted subcutaneously on the flanks of C57BL/6 mice and were then retrieved 6 or 14 weeks later (after fluconazole treatment for 4 or 12 weeks, respectively). Leukocyte counts demonstrated that implantation of the chambers did elicit an inflammatory response but that only small numbers of inflammatory cells were able to enter the chamber interior. Treatment with fluconazole at 10 mg/kg of body weight/day for 12 weeks not only reduced the numbers of viable organisms within the chambers compared to those in untreated mice (mean +/- standard deviation of log(10) CFU of 0.7 +/- 1.2 versus 2.3 +/- 2.0; P < 0.001 by the Bonferroni test) but also increased the numbers of chambers that became sterile over the treatment period (14 of 16 versus 6 of 19; P = 0.0009 by the chi-square test). However, treatment for only 4 weeks had minimal effects on the numbers of chamber CFU, and none of the chambers became sterile during this period. Distribution of retrieved organisms between interior fluid and the chamber filters was approximately equal in all the treatment groups. This model system appears to be useful for evaluating the effects of antifungal drugs over prolonged periods in vivo. Its use in the present study demonstrates that fluconazole can increase the rate of sterilization of C. albicans foci that are protected from the host's inflammatory response.

Multicentre study of the in vitro evaluation of moxifloxacin and other quinolones against community acquired respiratory pathogens

The in vitro activity of moxifloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin and trovafloxacin against 710 strains (180 Streptococcus pneumoniae, 180 Haemophilus influenzae, 160 Moraxella catarrhalis and 190 Streptococcus pyogenes) isolated from patients with community-acquired respiratory tract infections. MIC values for moxifloxacin, trovafloxacin were 0.25/0.25, 0.03/0.03, 0.06/0.03 and 0.125/0.0125 mg/l for S. pneumoniae, H. influenzae, M. catharralis and S. pyogenes. Based upon the MIC(90) values and the MIC distributions, moxifloxacin and trovafloxacin were the most active of the quinolones tested. They showed enhanced activity against Gram-positive organisms including penicillin non susceptible S. pneumoniae strains. Moxifloxacin was also highly active against ciprofloxacin-resistant S. pneumoniae strains.