Singh Meenakshi, Vaishnavi Chetana, Mahmood Safrun, Kochhar Rakesh
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
Front Med (Lausanne). 2017 Mar 28;4:33. doi: 10.3389/fmed.2017.00033. eCollection 2017.
is an important cause of infectious colitis among hospitalized patients across the globe. The pathogenic potential of in producing significant morbidity and mortality is mainly due to production of toxins A and B. The outbreaks of . infection (CDI) are due to changes in the genetic sequences of the organism. There is hardly any molecular study reported on the prevalent types of strains in India. Toxinotyping and sequencing of locally circulating . isolates from patients presenting to our tertiary care center of North India were done.
strains ( = 174) isolated from 1,110 fecal samples from patients with suspected CDI were subjected to toxinotyping and partial sequencing of A and B genes. Comparison of nucleotide sequences with reference 630 strain using BLAST was made and translated into corresponding amino acid sequences by ExPASy.
Of 174 isolates, 121 were toxigenic, belonging to toxinotype 0 ( = 76) and VIII ( = 45). Partial sequencing of toxin genes using bioinformatics approaches revealed changes in toxin A sequences of five (50%) isolates, but the translated nucleotide sequences showed substitution in only three of them. No variation was seen in the toxin B nucleotide sequences. Interstrain variations were found in the clinical isolates in our region.
PCR amplified toxigenic genes followed by sequencing can help to identify genetic changes and pathogenicity of varied collection of isolates.
在全球住院患者中，[病原体名称未给出]是感染性结肠炎的重要病因。[病原体名称未给出]产生显著发病率和死亡率的致病潜力主要归因于毒素A和毒素B的产生。[病原体名称未给出]感染（CDI）的暴发是由于该生物体基因序列的变化。在印度，几乎没有关于[病原体名称未给出]菌株流行类型的分子研究报道。对来自印度北部我们三级护理中心的患者中局部流行的[病原体名称未给出]分离株进行了毒素分型和测序。
从1110份疑似CDI患者的粪便样本中分离出的[病原体名称未给出]菌株（n = 174）进行毒素分型以及A和B基因的部分测序。使用BLAST将核苷酸序列与参考[病原体名称未给出]630菌株进行比较，并通过ExPASy翻译成相应的氨基酸序列。
在174株[病原体名称未给出]分离株中，121株产毒素，属于毒素型0（n = 76）和VIII（n = 45）。使用生物信息学方法对毒素基因进行部分测序，发现5株（50%）[病原体名称未给出]分离株的毒素A序列有变化，但翻译后的核苷酸序列仅在其中3株中显示有替换。毒素B核苷酸序列未见变异。在我们地区的临床[病原体名称未给出]分离株中发现了菌株间的差异。
PCR扩增产毒素基因后进行测序有助于鉴定不同[病原体名称未给出]分离株的基因变化和致病性。
