Department of Microbiology, London Health Sciences Centre, London, Ontario, Canada.
Int J Antimicrob Agents. 2011 Mar;37(3):248-52. doi: 10.1016/j.ijantimicag.2010.11.020. Epub 2011 Feb 4.
Coagulase-negative staphylococci (CoNS) have emerged as important nosocomial pathogens. CoNS resistance to meticillin and other semisynthetic penicillins is now common. Elevated vancomycin minimal inhibitory concentrations (MICs) have been reported and are associated with worse treatment outcomes. Several newer antibiotics have recently become available for the treatment of Gram-positive infections. The purpose of this study was to assess the in vitro activity of telavancin, daptomycin, linezolid and tigecycline in comparison with oxacillin and vancomycin against 653 non-duplicate clinical isolates of CoNS by the agar dilution method. The greatest variability in MIC was observed for oxacillin. Presence of the mecA gene conferred higher MICs for oxacillin but did not influence MICs to all other antibiotics tested. Telavancin tended to have MICs that were 1-2 dilutions lower than vancomycin. Daptomycin had good activity against all isolates. Staphylococcus haemolyticus, Staphylococcus hominis subsp. novobiosepticus, Staphylococcus saprophyticus, Staphylococcus schleiferi and Staphylococcus simulans were the most daptomycin-susceptible CoNS species tested. The validity of the agar dilution method for daptomycin was confirmed, with >90% isolates having MICs that were within 1 dilution of parallel Etest results. Within-species MIC variation was most restricted for linezolid and tigecycline, with the exception of Staphylococcus epidermidis and Staphylococcus haemolyticus that demonstrated higher overall MICs to tigecycline.
凝固酶阴性葡萄球菌（CoNS）已成为重要的医院获得性病原体。CoNS 对甲氧西林和其他半合成青霉素的耐药性现在很常见。已报道并与治疗结果较差相关的是万古霉素最小抑菌浓度（MIC）升高。最近有几种新型抗生素可用于治疗革兰氏阳性感染。本研究的目的是通过琼脂稀释法评估替拉万星、达托霉素、利奈唑胺和替加环素与苯唑西林和万古霉素相比对 653 例非重复临床 CoNS 分离株的体外活性。苯唑西林的 MIC 变化最大。mecA 基因的存在导致苯唑西林的 MIC 升高，但不影响所有其他测试抗生素的 MIC。替拉万星的 MIC 倾向于比万古霉素低 1-2 个稀释度。达托霉素对所有分离株均具有良好的活性。测试的 CoNS 中最易受达托霉素影响的物种为溶血葡萄球菌、解糖葡萄球菌亚种、腐生葡萄球菌、施莱弗葡萄球菌和模仿葡萄球菌。达托霉素琼脂稀释法的有效性得到了证实，超过 90%的分离株的 MIC 值与平行 Etest 结果相差 1 个稀释度。利奈唑胺和替加环素的种内 MIC 变化最受限制，除表皮葡萄球菌和溶血葡萄球菌对替加环素的总体 MIC 值较高外。
