Multidrug microbial resistance poses major challenges to the management of infection, particularly with the paucity of new drugs with activity against these bacteria. Since the turn of this century a few new antibiotics have been licensed, including linezolid, daptomycin and tigecycline. This supplement reports data presented at the 13th International Congress of Infectious Diseases held in Kuala Lumpur in June 2008. Dr R. Isturiz reviews the data on global resistance trends and the potential impact on empirical therapy; Dr J.-H. Song reviews new agents on the antimicrobial horizon; and the final paper in the supplement, by Dr L.R. Peterson, reviews the role of tigecycline in the management of complicated intra-abdominal and skin and soft tissue infections.
This study evaluated whether genotypically different clinical isolates of S. aureus have similar susceptibilities to individual antibiotics. It further aims to check the impact of biofilm on the in vitro activity of vancomycin, daptomycin, linezolid, and tigecycline against S. aureus clones. The study used a total of 60 different clinical MSSA and MRSA isolates. Susceptibilities were performed in planktonic cultures by macrobroth dilution and epsilon-test (E test) system. Biofilm production was determined using an adherent plate assay. The efficacy of antimicrobial activities against biofilms formation was checked using confocal laser scanning microscopy (CLSM). The study found that similar and different spa, MLST, and SCCmec types displayed high variation in their susceptibilities to antibiotics with tigecycline and daptomycin being the most effective. The biofilms were found resistant to high concentrations of most antibiotics tested with daptomycin being the most effective drug used in adhesive biofilms. A considerable difference exists among similar and various clone types against antibiotics tested. This variation could have contributed to the degree of virulence even within the same clonal genotype and enhanced heterogeneity in the infection potential. Thus, the development of a rapid and precise identification profile for each clone in human infections is important.