Nomura R, Nakano K, Nemoto H, Mukai T, Hata H, Toda K, Yoshioka H, Taniguchi K, Amano A, Ooshima T
Department of Pediatric Dentistry, Division of Oral Infection and Disease Control, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Oral Microbiol Immunol. 2009 Feb;24(1):43-9. doi: 10.1111/j.1399-302X.2008.00474.x.
BACKGROUND/AIMS: Infective endocarditis (IE) is caused by a microbial infection of the endothelial surface of the heart. Although blood culture examinations are commonly used to determine the associated bacterial species, molecular techniques, which enable rapid identification of targeted bacterial species, have recently been applied in clinical cases.
Nine heart valve specimens from IE patients (six subacute cases and three acute cases) were extirpated and collected, then bacterial DNA was extracted. Bacterial species in the specimens were determined by two different molecular methods and the results were compared with those from a conventional blood culture technique. In addition, a comparison between the two molecular methods was carried out using known numbers of six streptococcal species.
The conventional blood culture method revealed the bacterial species in eight cases, while one was found to be negative. Multiple species were identified in most of the cases by both molecular methods; however, those specified by one method were not always consistent with those specified by the other. Furthermore, the species determined by the blood culture technique were not always identified by the molecular methods. We also found that the two molecular methods used in the present study were extremely sensitive to detect from 1 to 100 cells of individual oral streptococcal species.
Our results suggest that species specified by molecular methods may have disseminated incidentally into the bloodstream, so interpretation of such results should be carefully undertaken in clinical situations.
背景/目的：感染性心内膜炎（IE）是由心脏内皮表面的微生物感染引起的。尽管血培养检查通常用于确定相关细菌种类，但能够快速鉴定目标细菌种类的分子技术最近已应用于临床病例。
从IE患者身上切除并收集9个心脏瓣膜标本（6例亚急性病例和3例急性病例），然后提取细菌DNA。通过两种不同的分子方法确定标本中的细菌种类，并将结果与传统血培养技术的结果进行比较。此外，使用已知数量的六种链球菌对两种分子方法进行比较。
传统血培养方法在8例中检测出细菌种类，1例为阴性。两种分子方法在大多数病例中都鉴定出多种细菌种类；然而，一种方法确定的种类并不总是与另一种方法确定的种类一致。此外，血培养技术确定的种类并不总是能通过分子方法鉴定出来。我们还发现，本研究中使用的两种分子方法对检测单个口腔链球菌种类的1至100个细胞极其敏感。
我们的结果表明，分子方法确定的种类可能是偶然扩散到血液中的，因此在临床情况下应谨慎解释此类结果。
