Identification of common virulence factors present in enterotoxigenic Escherichia coli isolated from diarrhoeal patients in Kolkata, India.

ABSTRACT

AIMS: Development of an effective vaccine against enterotoxigenic Escherichia coli (ETEC) is largely dependent on the conscientious understanding of different virulence associated factors from diverse geographical areas. So, the objective of this study is to elucidate the distribution of enterotoxins, CF and NCVF in clinical ETEC strains isolated between 2008 and 2014 from two hospitals in Kolkata, India. METHODS AND RESULTS: Multiplex PCR method was used for detection of two enterotoxin genes, 11 common CFs and five common NCVFs. Among the 350 tested ETEC strains, 61% strains possessed est+elt genes, 25% est and 14% elt. Among 56% CF positive ETEC strains, CS21 was the prevalent one (37%) followed by CS6 (36%). NCVF genes were present in 59% of the ETEC strains; eatA was the most prevalent (65%) followed by etpA (51%). There were 29% strains negative for any CFs or NCVFs. CONCLUSIONS: We conclude that a pattern exists between CS6, eatA and toxins. We observed est with or without elt, CS6 with or without CS5 and with or without eatA were present in 24% of clinical ETEC strains (59/250) analysed. CS21 has emerged as another predominant CF but it had diverse CFs and NCVFs. SIGNIFICANCE AND IMPACT OF THE STUDY Prevalence of ETEC virulence factors would help in tracking ETEC globally and suggests the need of a multivalent ETEC vaccine.