Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Korea.
Department of Internal Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Korea.
Ann Lab Med. 2017 Nov;37(6):505-510. doi: 10.3343/alm.2017.37.6.505.
Cases of infective endocarditis (IE) require prompt etiological diagnosis for effective treatment. Molecular methods can aid in rapid and reliable diagnosis of culture-negative IE cases. We evaluated the utility of 16S rDNA PCR and sequencing in determining the causative agents of IE in valve tissues, especially when specimens were obtained after initiation of antimicrobial therapy.
We performed 16S rDNA PCR and sequencing in heart valve specimens and medical records review of 80 patients who underwent protocol-based cardiac surgery from 2013 to 2015. One patient did not meet the criteria for IE. Sixty-five (81.3%) and 14 pa-tients (17.5%) were diagnosed as having definite IE and possible IE, respectively. Blood and heart valve biopsy tissue were examined by using routine microbiological methods.
Blood cultures in our hospital were IE-positive for 33 patients (41.8%), whereas 49 patients (62.0%) showed positive blood cultures when initial blood cultures performed at the referring hospital were included. Eighteen (22.8%) and 40 patients (50.6%) were IE-positive in valve tissue cultures and 16S rDNA PCR, respectively. Bacteria in the Streptococcus mitis group (n=26) were the most common etiological agents of IE. Eight (10.1%) culture-negative specimens tested positive by 16S rDNA PCR. In five of eight PCR-positive and culture-negative cases, fastidious or anaerobic organisms were the cause of IE.
Direct 16S rDNA PCR and sequencing can be used as a supplementary method to conventional blood and biopsy culture testing, especially in culture-negative IE cases that are negative for IE by culture.
感染性心内膜炎（IE）病例需要及时进行病因诊断，以便进行有效治疗。分子方法有助于快速可靠地诊断培养阴性的 IE 病例。我们评估了 16S rDNA PCR 和测序在确定心瓣膜组织中 IE 致病原中的作用，特别是在开始抗菌治疗后获得标本时。
我们对 2013 年至 2015 年期间接受基于方案的心脏手术的 80 例患者的心脏瓣膜标本进行了 16S rDNA PCR 和测序，并对其病历进行了回顾性分析。有 1 例患者不符合 IE 的标准。65 例（81.3%）和 14 例（17.5%）患者分别被诊断为明确的 IE 和可能的 IE。采用常规微生物学方法检查血和心瓣膜活检组织。
我们医院的血培养 IE 阳性率为 33 例（41.8%），如果将转诊医院进行的初始血培养阳性的 49 例（62.0%）计算在内。18 例（22.8%）和 40 例（50.6%）患者的心瓣膜组织培养和 16S rDNA PCR 阳性。在最常见的 IE 病因中，缓症链球菌组（n=26）细菌占主导地位。8 例（10.1%）培养阴性的标本通过 16S rDNA PCR 检测呈阳性。在 8 例 PCR 阳性且培养阴性的病例中，有 5 例为培养困难或厌氧菌引起的 IE。
直接 16S rDNA PCR 和测序可作为传统血培养和活检培养检测的补充方法，特别是在培养阴性且 IE 培养阴性的 IE 病例中。
