Toxinotyping and Sequencing of Isolates from Patients in a Tertiary Care Hospital of Northern India.

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS AND DISCUSSION

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.

CONCLUSION

PCR amplified toxigenic genes followed by sequencing can help to identify genetic changes and pathogenicity of varied collection of isolates.