Billström Hanna, Lund Bodil, Sullivan Asa, Nord Carl Erik
Division of Clinical Microbiology, F68, Karolinska Institutet, Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden.
Int J Antimicrob Agents. 2008 Nov;32(5):374-7. doi: 10.1016/j.ijantimicag.2008.04.026. Epub 2008 Aug 19.
The aim of the present study was to determine the occurrence of seven virulence determinants in Enterococcus faecium clinical blood culture isolates over a 6-year period and to investigate possible correlations between virulence and antibiotic resistance. Two hundred and sixty-three isolates were screened for the presence of genes coding for aggregation substance (asa1), cytolysin (cylA), collagen-binding protein (ace), Enterococcusfaecalis endocarditis antigen (efaA(fs)), enterococcal surface protein (esp(fm)), gelatinase (gelE) and hyaluronidase (hyl(fm)) by polymerase chain reaction. The minimum inhibitory concentrations (MICs) of ampicillin, ciprofloxacin, gentamicin, imipenem, linezolid and vancomycin were determined by the agar dilution method and the MIC of daptomycin was determined by Etest. The esp(fm) gene was found in 56% of the isolates, hyl(fm) in 4%, whilst the other virulence genes were detected only sporadically (< or = 1%). The level of antibiotic resistance was 77% to ampicillin, 90% to ciprofloxacin and 83% to imipenem; 5% of the isolates were resistant to vancomycin and 2% were resistant to gentamicin (high-level resistance, MIC > or = 500 mg/L). A significant correlation was found between the presence of esp(fm) and resistance to ampicillin, ciprofloxacin and imipenem (P<0.01). Twelve isolates were esp(fm)-positive and ampicillin-susceptible.
本研究的目的是确定粪肠球菌临床血培养分离株在6年期间7种毒力决定因素的出现情况，并调查毒力与抗生素耐药性之间的可能相关性。通过聚合酶链反应对263株分离株进行筛选，检测编码聚集物质（asa1）、细胞溶素（cylA）、胶原结合蛋白（ace）、粪肠球菌心内膜炎抗原（efaA(fs)）、肠球菌表面蛋白（esp(fm)）、明胶酶（gelE）和透明质酸酶（hyl(fm)）的基因。采用琼脂稀释法测定氨苄西林、环丙沙星、庆大霉素、亚胺培南、利奈唑胺和万古霉素的最低抑菌浓度（MIC），采用Etest法测定达托霉素的MIC。在56%的分离株中发现了esp(fm)基因，4%的分离株中发现了hyl(fm)基因，而其他毒力基因仅偶尔检测到（≤1%）。对氨苄西林的耐药水平为77%，对环丙沙星为90%，对亚胺培南为83%；5%的分离株对万古霉素耐药，2%的分离株对庆大霉素耐药（高水平耐药，MIC≥500mg/L）。发现esp(fm)的存在与对氨苄西林、环丙沙星和亚胺培南的耐药性之间存在显著相关性（P<0.01）。12株分离株esp(fm)阳性且对氨苄西林敏感。
