Espírito-Santo M P, Carneiro M A S, Reis N R S, Kozlowski A G, Teles S A, Lampe E, Yoshida C F T, Martins R M B
Departamento de Virologia, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, Brasil.
Braz J Med Biol Res. 2007 Apr;40(4):545-50. doi: 10.1590/s0100-879x2007000400013.
The present study examined the distribution of hepatitis C virus (HCV) genotypes and subtypes in a hemodialysis population in Goiás State, Central Brazil, and evaluated the efficiency of two genotyping methods: line probe assay (LiPA) based on the 5' noncoding region and nucleotide sequencing of the nonstructural 5B (NS5B) region of the genome. A total of 1095 sera were tested for HCV RNA by RT-nested PCR of the 5' noncoding region. The LiPA assay was able to genotype all 131 HCV RNA-positive samples. Genotypes 1 (92.4%) and 3 (7.6%) were found. Subtype 1a (65.7%) was the most prevalent, followed by subtypes 1b (26.7%) and 3a (7.6%). Direct nucleotide sequencing of 340 bp from the NS5B region was performed in 106 samples. The phylogenetic tree showed that 98 sequences (92.4%) were classified as genotype 1, subtypes 1a (72.6%) and 1b (19.8%), and 8 sequences (7.6%) as subtype 3a. The two genotyping methods gave concordant results within HCV genotypes and subtypes in 100 and 96.2% of cases, respectively. Only four samples presented discrepant results, with LiPA not distinguishing subtypes 1a and 1b. Therefore, HCV genotype 1 (subtype 1a) is predominant in hemodialysis patients in Central Brazil. By using sequence analysis of the NS5B region as a reference standard method for HCV genotyping, we found that LiPA was efficient at the genotype level, although some discrepant results were observed at the subtype level (sensitivity of 96.1% for subtype 1a and 95.2% for subtype 1b). Thus, analysis of the NS5B region permitted better discrimination between HCV subtypes, as required in epidemiological investigations.
本研究调查了巴西中部戈亚斯州血液透析人群中丙型肝炎病毒（HCV）基因型和亚型的分布情况，并评估了两种基因分型方法的效率：基于5'非编码区的线性探针分析（LiPA）以及对基因组非结构5B（NS5B）区进行核苷酸测序。通过对5'非编码区进行逆转录巢式PCR检测了总共1095份血清中的HCV RNA。LiPA分析能够对所有131份HCV RNA阳性样本进行基因分型。发现了基因型1（92.4%）和基因型3（7.6%）。其中1a亚型（65.7%）最为常见，其次是1b亚型（26.7%）和3a亚型（7.6%）。对106份样本进行了NS5B区340 bp的直接核苷酸测序。系统发育树显示，98个序列（92.4%）被分类为基因型1，其中1a亚型（72.6%）和1b亚型（19.8%），8个序列（7.6%）为3a亚型。两种基因分型方法在HCV基因型和亚型方面的结果一致性分别为100%和96.2%。只有4个样本结果不一致，LiPA无法区分1a和1b亚型。因此，HCV基因型1（1a亚型）在巴西中部血液透析患者中占主导地位。以NS5B区序列分析作为HCV基因分型的参考标准方法，我们发现LiPA在基因型水平上是有效的，尽管在亚型水平上观察到了一些不一致的结果（1a亚型的敏感性为96.1%，1b亚型为95.2%）。因此，NS5B区分析能够更好地区分HCV亚型，这是流行病学调查所需要的。
