Ozüberk Osman Özüberk, Gökahmetoğlu Selma, Ozçelik Bülent, Ekmekçioğlu Oğuz
Erciyes University Faculty of Medicine, Department of Medical Microbiology, Kayseri, Turkey.
Mikrobiyol Bul. 2013 Jan;47(1):79-86. doi: 10.5578/mb.4208.
Chlamydia trachomatis infection is considered the most prevalent bacterial sexually transmitted disease worldwide. C.trachomatis causes eye infections such as trachoma and newborn inclusion conjunctivitis, newborn pneumonia, genitourinary system infections and suppurative inguinal lymphadenitis namely lymphogranuloma venerum. The aim of this study was to investigate C.trachomatis by direct fluorescent antibody (DFA), polymerase chain reaction (PCR) and cell culture methods in the clinical samples sent to the microbiology laboratory with the prediagnosis of genital infections. A total of 50 swab samples obtained from adult patients (49 female, 1 male) who were admitted to Erciyes University Hospital, Kayseri, Turkey between February-March 2010, were included in the study. C.trachomatis antigens were investigated by a commercial DFA (PathoDx, Remel, USA) method. McCoy cell cultures prepared in microplate wells were used for the isolation of C.trachomatis. The growth of C.trachomatis in cell cultures was confirmed by DFA and iodine staining methods. C.trachomatis DNA was investigated by commercially available PCR (Chlamydia trachomatis 330/740 IC; Sacace, Italy) method. In our study, 4 (8%) of the 50 swab samples were found positive with DFA, 1 (2%) was positive with cell culture, and 1 (2%) was positive with PCR. The only sample that gave positive results with all of the three methods was an urethral swab. Three cervical swab samples that were found positive only with DFA method was evaluated as false positivity. When cell culture was considered as the reference method, the sensitivity and specificity of DFA method were estimated as 100% and 94%, respectively, while those rates for PCR were 100% and 100%, respectively. In conclusion, although cell culture is still the gold standard in the diagnosis of C.trachomatis. infections, since it is time consuming and difficult to apply, more rapid and reliable PCR methods may be applied in diagnosis. DFA method which is practical and cheap, is preferred largely in routine laboratory practice. However, false negative and false positive DFA results should be prevented by the maintainence of good quality clinical specimens, evaluation of the test by experienced personnel and use of quality control samples in each run.
沙眼衣原体感染被认为是全球最常见的细菌性性传播疾病。沙眼衣原体可引起眼部感染，如沙眼和新生儿包涵体结膜炎、新生儿肺炎、泌尿生殖系统感染以及化脓性腹股沟淋巴结炎即性病性淋巴肉芽肿。本研究的目的是采用直接荧光抗体（DFA）、聚合酶链反应（PCR）和细胞培养方法，对送至微生物实验室进行生殖器感染预诊断的临床样本中的沙眼衣原体进行检测。本研究纳入了2010年2月至3月间在土耳其开塞利埃尔西耶斯大学医院就诊的成年患者（49名女性，1名男性）所采集的共50份拭子样本。采用商用DFA（PathoDx，Remel，美国）方法检测沙眼衣原体抗原。用微孔板孔中制备的 McCoy 细胞培养物分离沙眼衣原体。通过DFA和碘染色方法确认沙眼衣原体在细胞培养物中的生长情况。采用市售PCR（沙眼衣原体330/740 IC；Sacace，意大利）方法检测沙眼衣原体DNA。在我们的研究中，50份拭子样本中有4份（8%）DFA检测呈阳性，1份（2%）细胞培养呈阳性，1份（2%）PCR检测呈阳性。三种方法检测结果均为阳性的唯一样本是一份尿道拭子。仅DFA方法检测呈阳性的三份宫颈拭子样本被评估为假阳性。以细胞培养作为参考方法时，DFA方法的敏感性和特异性分别估计为100%和94%，而PCR的相应比率分别为100%和100%。总之，虽然细胞培养仍是诊断沙眼衣原体感染的金标准，但由于其耗时且应用困难，在诊断中可采用更快速可靠的PCR方法。DFA方法实用且成本低廉，在常规实验室实践中大多被优先选用。然而，应通过保持高质量的临床标本、由经验丰富的人员进行检测评估以及每次检测使用质量控制样本等措施，防止DFA出现假阴性和假阳性结果。
