Nakamura Ayako, Oguri Toyoko, Misawa Shigeki, Tabe Yoko, Kondo Sigemi, Miyake Kazunori, Miyake Noriko, Igari Jun, Ohsaka Akimichi
Clinical Laboratory, Juntendo University Hospital, Tokyo, Japan.
Jpn J Antibiot. 2007 Jun;60(3):153-60.
We evaluated the efficacy of cefotiam (CTM) against Staphylococcus epidermidis (S. epidermidis) isolated from blood culture and central venous catheters. Of the S. epidermidis strains tested, 82.3% were methicillin (MPIPC)-resistant (MPIPC MIC > or = 0.5 microg/ml) and expressed the mecA gene, and 89.2% of these MPIPC-resistant S. epidermidis (MRSE) showed less than 8.0 microg/ml CTM MIC. In vitro killing kinetics of CTM against MRSE demonstrated that strains with high CTM MIC (> or = 4.0 microg/ml) showed high MPIPC MIC (> or = 4.0 microg/ml). All strains with low CTM MIC (< or = 2.0 microg/ml) showed MPIPC MIC lower than 2.0 microg/ml. In time-kill studies, CTM had high bactericidal activity against strains with low CTM MIC (< or = 2.0 microg/ml), regardless of whether they were mecA positive. These results demonstrated that MRSE isolates with low CTM MIC (< or = 2.0 microg/ml) are not easily induced CTM resistance by CTM treatment in vitro, and indicated the possibility that beta-lactams such as CTM could be an effective antibiotic agents against beta-lactam-sensitive MRSE infections.
我们评估了头孢替安（CTM）对从血培养和中心静脉导管分离出的表皮葡萄球菌的疗效。在测试的表皮葡萄球菌菌株中，82.3%对甲氧西林（MPIPC）耐药（MPIPC MIC≥0.5μg/ml）并表达mecA基因，并且这些耐甲氧西林表皮葡萄球菌（MRSE）中有89.2%的头孢替安MIC低于8.0μg/ml。头孢替安对MRSE的体外杀菌动力学表明，头孢替安MIC高（≥4.0μg/ml）的菌株显示出甲氧西林MIC高（≥4.0μg/ml）。所有头孢替安MIC低（≤2.0μg/ml）的菌株显示甲氧西林MIC低于2.0μg/ml。在时间-杀菌研究中，头孢替安对头孢替安MIC低（≤2.0μg/ml）且mecA是否阳性的菌株均具有高杀菌活性。这些结果表明，体外头孢替安治疗不易诱导头孢替安MIC低（≤2.0μg/ml）的MRSE分离株产生耐药性，并提示头孢替安等β-内酰胺类药物可能是治疗β-内酰胺敏感MRSE感染的有效抗生素。
