AUTHOR=Singh Meenakshi , Vaishnavi Chetana , Mahmood Safrun , Kochhar Rakesh 

TITLE=Toxinotyping and Sequencing of Clostridium difficile Isolates from Patients in a Tertiary Care Hospital of Northern India

JOURNAL=Frontiers in Medicine

VOLUME=4

YEAR=2017

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2017.00033

DOI=10.3389/fmed.2017.00033

ISSN=2296-858X

ABSTRACT=<sec id="ST1"><title>Background</title><p><italic>Clostridium difficile</italic> is an important cause of infectious colitis among hospitalized patients across the globe. The pathogenic potential of <italic>C. difficile</italic> in producing significant morbidity and mortality is mainly due to production of toxins A and B. The outbreaks of <italic>C</italic>. <italic>difficile</italic> 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 <italic>C. difficile</italic> strains in India. Toxinotyping and sequencing of locally circulating <italic>C</italic>. <italic>difficile</italic> isolates from patients presenting to our tertiary care center of North India were done.</p></sec><sec id="ST2"><title>Materials and methods</title><p><italic>C. difficile</italic> strains (<italic>n</italic> = 174) isolated from 1,110 fecal samples from patients with suspected CDI were subjected to toxinotyping and partial sequencing of <italic>tcd</italic>A and <italic>tcd</italic>B genes. Comparison of nucleotide sequences with reference <italic>C. difficile</italic> 630 strain using BLAST was made and translated into corresponding amino acid sequences by ExPASy.</p></sec><sec id="ST3"><title>Results and discussion</title><p>Of 174 <italic>C. difficile</italic> isolates, 121 were toxigenic, belonging to toxinotype 0 (<italic>n</italic> = 76) and VIII (<italic>n</italic> = 45). Partial sequencing of toxin genes using bioinformatics approaches revealed changes in toxin A sequences of five (50%) <italic>C. difficile</italic> 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 <italic>C. difficile</italic> isolates in our region.</p></sec><sec id="ST4"><title>Conclusion</title><p>PCR amplified toxigenic genes followed by sequencing can help to identify genetic changes and pathogenicity of varied collection of <italic>C. difficile</italic> isolates.</p></sec>