Moussa Amal, Fredj Mouna Ben Hadj, BenHamida-Rebaï Meriam, Fodha Imene, Boujaafar Noureddine, Trabelsi Abdelhalim
Faculty of Pharmacy, University of Monastir, 5000 Monastir, Tunisia.
LR14SP02, Epidemiology and Immunogenetics of Human Viral Infections, Laboratory of Microbiology, Sahloul University Hospital, 4054 Sousse, Tunisia.
J Med Microbiol. 2017 Feb;66(2):112-118. doi: 10.1099/jmm.0.000420. Epub 2017 Mar 7.
Group A rotavirus (RVA) is the leading cause of severe gastroenteritis in children younger than 5 years. The most common human G-types are G1-4 and G9. G12 genotype is currently emerging worldwide, becoming the sixth most prevalent RVA G-genotype. In Tunisia, an emergence of G12 RVA strains was observed. To understand the evolution and origin of these Tunisian G12 strains, phylogenetic analyses were conducted.
A total of 1127 faecal samples were collected from Tunisian children under 5 years consulting for gastroenteritis between 2009 and 2014. Samples were screened by ELISA for the presence of RVA antigen. RVA-positive samples were used for the detection of G12 RVA strains by semi-nested RT-PCR. G12-positive specimens were subjected to VP4 genotyping reaction. PCR products of the G12-positive samples were sequenced and characterized by phylogenetic analysis of partial VP7 gene sequence.
Globally, 270 (24 %) stool specimens were RVA-positive. Fourteen presented the G12 genotype (5.2 %) and were found to be in combination with either the P[6] (50.0 %) or the P[8] (50.0 %) genotype. Phylogenetic analysis revealed that all characterized Tunisian G12 strains clustered in the modern G12 lineage III and appear to form three different subclusters.
Thus, the Tunisian G12 strains may have originated from not a single, but at least three distinct ancestral G12 strains. Detailed molecular characterization of the entire genome of these strains remains essential to help determine the extent of genetic variation and the relatedness of Tunisian G12 RVA strains to G12 strains described worldwide.
A组轮状病毒（RVA）是5岁以下儿童严重胃肠炎的主要病因。最常见的人类G型为G1 - 4和G9。G12基因型目前正在全球出现，成为第六大流行的RVA G基因型。在突尼斯，观察到G12 RVA毒株的出现。为了解这些突尼斯G12毒株的进化和起源，进行了系统发育分析。
2009年至2014年间，从突尼斯5岁以下因胃肠炎就诊的儿童中总共收集了1127份粪便样本。通过ELISA筛选样本中RVA抗原的存在。RVA阳性样本用于通过半巢式RT - PCR检测G12 RVA毒株。G12阳性标本进行VP4基因分型反应。对G12阳性样本的PCR产物进行测序，并通过部分VP7基因序列的系统发育分析进行表征。
全球范围内，270份（24%）粪便标本RVA呈阳性。14份呈现G12基因型（5.2%），并发现与P[6]（50.0%）或P[8]（50.0%）基因型组合。系统发育分析表明，所有特征化的突尼斯G12毒株聚集在现代G12谱系III中，似乎形成三个不同的亚群。
因此，突尼斯G12毒株可能并非起源于单一的，而是至少三个不同的祖先G12毒株。对这些毒株的全基因组进行详细的分子表征仍然至关重要，以帮助确定遗传变异程度以及突尼斯G12 RVA毒株与全球描述的G12毒株的相关性。
