Lück P C, Schmitt J W, Hengerer A, Helbig J H
Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum, TU Dresden, D-01307 Dresden, Germany.
Antimicrob Agents Chemother. 1998 Nov;42(11):2870-6. doi: 10.1128/AAC.42.11.2870.
We determined the MICs of ampicillin, ciprofloxacin, erythromycin, imipenem, and rifampin for two clinical isolates of Legionella pneumophila serogroup 1 by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) reduction assay and by quantitative culture. To test the influence of subinhibitory concentrations (sub-MICs) of antimicrobial agents on Legionella uptake into Acanthamoeba castellanii and U937 macrophage-like cells, both strains were pretreated with 0.25 MICs of the antibiotics for 24 h. In comparison to that for the untreated control, subinhibitory concentrations of antibiotics significantly reduced Legionella uptake into the host cells. Measurement of the binding of monoclonal antibodies against several Legionella antigens by enzyme-linked immunoassays indicated that sub-MIC antibiotic treatment reduced the expression of the macrophage infectivity potentiator protein (Mip), the Hsp 60 protein, the outer membrane protein (OmpM), an as-yet-uncharacterized protein of 55 kDa, and a few lipopolysaccharide (LPS) epitopes. In contrast, the expression of some LPS epitopes recognized by monoclonal antibodies 8/5 and 30/4 as well as a 45-kDa protein, a 58-kDa protein, and the major outer membrane protein (OmpS) remained unaffected.
我们通过3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）还原试验和定量培养法，测定了氨苄西林、环丙沙星、红霉素、亚胺培南和利福平对两株嗜肺军团菌血清1型临床分离株的最低抑菌浓度（MIC）。为了测试抗菌药物的亚抑菌浓度（亚MIC）对嗜肺军团菌被卡氏棘阿米巴和U937巨噬细胞样细胞摄取的影响，两株菌均用0.25倍MIC的抗生素预处理24小时。与未处理的对照相比，抗生素的亚抑菌浓度显著降低了嗜肺军团菌对宿主细胞的摄取。通过酶联免疫吸附测定法检测针对几种军团菌抗原的单克隆抗体的结合情况，结果表明亚MIC抗生素处理降低了巨噬细胞感染增强蛋白（Mip）、热休克蛋白60（Hsp 60）、外膜蛋白（OmpM）、一种尚未鉴定的55 kDa蛋白以及一些脂多糖（LPS）表位的表达。相比之下，单克隆抗体8/5和30/4识别的一些LPS表位以及一种45 kDa蛋白、一种58 kDa蛋白和主要外膜蛋白（OmpS）的表达未受影响。
