title: Toxinotyping and Sequencing ofClostridium difficileIsolates from Patients in a Tertiary Care Hospital of Northern India.
abstract: BACKGROUND
  Clostridium difficileis an important cause of infectious colitis among hospitalized patients across the globe. The pathogenic potential ofC. difficilein producing significant morbidity and mortality is mainly due to production of toxins A and B. The outbreaks ofC.difficileinfection (CDI) are due to changes in the genetic sequences of the organism. There is hardly any molecular study reported on the prevalent types ofC. difficilestrains in India. Toxinotyping and sequencing of locally circulatingC.difficileisolates from patients presenting to our tertiary care center of North India were done.
  
  
  METHODS
  C. difficilestrains (n= 174) isolated from 1,110 fecal samples from patients with suspected CDI were subjected to toxinotyping and partial sequencing oftcdA andtcdB genes. Comparison of nucleotide sequences with referenceC. difficile630 strain using BLAST was made and translated into corresponding amino acid sequences by ExPASy.
  
  
  CONCLUSIONS
  Of 174C. difficileisolates, 121 were toxigenic, belonging to toxinotype 0 (n= 76) and VIII (n= 45). Partial sequencing of toxin genes using bioinformatics approaches revealed changes in toxin A sequences of five (50%)C. difficileisolates, 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 clinicalC. difficileisolates in our region.
  
  
  CONCLUSIONS
  PCR amplified toxigenic genes followed by sequencing can help to identify genetic changes and pathogenicity of varied collection ofC. difficileisolates.
authors.affiliation: Department of Gastroenterology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Singh
authors.affiliation: Department of Gastroenterology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
authors.forename: Chetana
authors.initials: C
authors.lastname: Vaishnavi
authors.affiliation: Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
authors.forename: Safrun
authors.initials: S
authors.lastname: Mahmood
authors.affiliation: Department of Gastroenterology, Postgraduate Institute of Medical Education and Research , Chandigarh , India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kochhar
keywords: Clostridium difficile; sequencing; tcdA; tcdB; toxinotyping