Department of Oral Microbiology and Immunology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.
J Oral Microbiol. 2012;4. doi: 10.3402/jom.v4i0.10855. Epub 2012 Feb 22.
This study evaluates the presence of virulence factors and antibiotic susceptibility among enterococcal isolates from oral mucosal and deep infections.
Forty-three enterococcal strains from oral mucosal lesions and 18 from deep infections were isolated from 830 samples that were sent during 2 years to Oral Microbiology, University of Gothenburg, for analysis. The 61 strains were identified by 16S rDNA, and characterized by the presence of the virulence genes efa A (endocarditis gene), gel E (gelatinase gene), ace (collagen binding antigen gene), asa (aggregation substance gene), cyl A (cytolysin activator gene) and esp (surface adhesin gene), tested for the production of bacteriocins and presence of plasmids. MIC determination was performed using the E-test method against the most commonly used antibiotics in dentistry, for example, penicillin V, amoxicillin and clindamycin. Vancomycin was included in order to detect vancomycin-resistant enterococci (VRE) strains.
Sixty strains were identified as Enterococcus faecalis and one as Enterococcus faecium. All the virulence genes were detected in more than 93.3% (efa A and esp) of the E. faecalis strains, while the presence of phenotypic characteristics was much lower (gelatinase 10% and hemolysin 16.7%). Forty-six strains produced bacteriocins and one to six plasmids were detected in half of the isolates.
Enterococcal strains from oral infections had a high virulence capacity, showed bacteriocin production and had numerous plasmids. They were generally susceptible to ampicillins but were resistant to clindamycin, commonly used in dentistry, and no VRE-strain was found.
本研究评估了口腔黏膜和深部感染分离的肠球菌株的毒力因子和抗生素敏感性。
从 830 份在 2 年内送到哥德堡大学口腔微生物学进行分析的样本中分离出 43 株口腔黏膜病变和 18 株深部感染的肠球菌株。这 61 株菌通过 16S rDNA 鉴定，并通过存在毒力基因efa A（心内膜炎基因）、gel E（明胶酶基因）、ace（胶原结合抗原基因）、asa（聚集物质基因）、cyl A（细胞溶解素激活基因）和 esp（表面黏附素基因）来表征，检测细菌素的产生和质粒的存在。使用 E 试验法测定 MIC，针对口腔医学中最常用的抗生素，如青霉素 V、阿莫西林和克林霉素。加入万古霉素以检测耐万古霉素肠球菌（VRE）株。
60 株被鉴定为粪肠球菌，1 株为屎肠球菌。所有毒力基因均在超过 93.3%（efa A 和 esp）的粪肠球菌株中检测到，而表型特征的存在率要低得多（明胶酶 10%，溶血素 16.7%）。46 株产生细菌素，一半的分离株中检测到 1 至 6 个质粒。
口腔感染的肠球菌株具有高毒力，产生细菌素，并有大量质粒。它们通常对氨苄西林敏感，但对克林霉素耐药，克林霉素是口腔医学中常用的抗生素，未发现 VRE 株。
