National STD Reference Laboratory, Chinese Academy of Medical Sciences and Peking Union Medical College Institute of Dermatology, National Center for STD Control, Nanjing, China.
Sex Transm Dis. 2012 Jan;39(1):42-5. doi: 10.1097/OLQ.0b013e318232697d.
There have been limited data on molecular epidemiology of syphilis in China. This study aimed to analyze strain type distribution of Treponema pallidum causing early syphilis across geographic areas in China using an enhanced method.
Genital samples were collected from patients in East, South, and North China. Positive DNA of T. pallidum was analyzed by arp, tpr, and tp0548 genes.
Sufficient DNA for full molecular typing existed in 197 of 324 samples, and 27 strain types were identified. A range of 3 to 20 repeats (except 4, 11, and 19 repeats) and 25 repeats were found for the 60-bp tandem repeats of the arp gene. This was the first time the 9 and 25 repeats were detected. For the RFLP analysis of the tpr genes, patterns a, d, h, j, and l were identified. This was the first time the h, j, and l patterns were observed in China. For the sequence analysis of the tp0548 gene, sequences c, e, and f were identified. Strain type distribution was significantly different across geographic areas (χ² = 20.6, P = 0.006). Overall, 14d/f was most predominant (39% of fully typed samples, 95% CI = 32%-46%); 13d/f, 15d/f, and 16d/f were next most common (each 13% of fully typed samples, 95% CI = 9%-18%).
There is substantial genetic diversity of T. pallidum in China. The broad and ununiform distribution of strain types may reflect differences in regional sexual network patterns. Predominance of few strain types may indicate a linked transmission.
中国关于梅毒分子流行病学的数据有限。本研究旨在采用增强型方法分析中国不同地理区域早期梅毒患者感染的梅毒螺旋体菌株类型分布。
采集来自中国东部、南部和北部患者的生殖器样本。采用 arp、tpr 和 tp0548 基因分析梅毒螺旋体阳性 DNA。
在 324 个样本中，有 197 个样本有足够的 DNA 进行全分子分型，共鉴定出 27 种菌株类型。arp 基因 60bp 串联重复的重复次数范围为 3 到 20 次（除 4、11 和 19 次外）和 25 次。这是首次检测到 9 次和 25 次重复。tpr 基因的 RFLP 分析鉴定出 a、d、h、j 和 l 型。这是中国首次观察到 h、j 和 l 型。tp0548 基因序列分析鉴定出序列 c、e 和 f。菌株类型分布在地理区域之间存在显著差异（χ²=20.6，P=0.006）。总体而言，14d/f 最为常见（完全分型样本的 39%，95%CI=32%-46%）；13d/f、15d/f 和 16d/f 次之（每个均占完全分型样本的 13%，95%CI=9%-18%）。
中国梅毒螺旋体具有丰富的遗传多样性。菌株类型的广泛和不均匀分布可能反映了区域间性网络模式的差异。少数菌株类型的优势可能表明存在关联传播。
