Genotypic Characterization of Enterotoxigenic Escherichia coli Strains Causing Traveler's Diarrhea

Abstract

e This study aims to characterize the presence of virulence factors of enterotoxigenic Escherichia coli (ETEC) causing traveler's diarrhea. Among 52 ETEC isolates, the most common toxin type was STh, and the most frequent colonization factors (CFs) were CS21, CS6, and CS3. On the other hand, the nonclassical virulence factors EAST1 and EatA were frequently present.

Colonization Factors in Enterotoxigenic Escherichia coli Strains in Travelers to Mexico, Guatemala, and India Compared with Children in Houston, Texas

“…[28][29][30] In a study of international travelers returning to Spain, 30 of 52 (58%) of ETEC strains isolated were CS21 positive and 14 of 52 (27%) were CS6 positive. 31 A study of a killed oral vaccine combining Vibrio cholerae-binding toxin plus ETEC CFs, carried out in Mexico and Guatemala, was of limited value because it did not contain CS6 found in prevalent ETEC strains encountered in the study. 22 The lead scientific group working with this vaccine is now adding CS6 to the vaccine.…”

“…Among the nonclassical VFs are the EAST1 and EatA protein which have been found in 65% and 48% of the isolates among Spanish travelers 35 . We did not test for any nonclassical VF, which is an important limitation of the study.…”

Molecular analysis and antimicrobial susceptibility of enterotoxigenic Escherichia coli from diarrheal patients

“…ETEC produces one or both of LT and heat-stable toxin, which can, respectively, promote the cyclic levels of cyclic AMP and cyclic GMP (cGMP) through binding to intracellular adenyl-cyclase (Kaper et al, 2004;Nataro and Kaper, 1998). In addition, recent studies have looked into a number of chromosomal determinants that could be associated with ETEC virulence, such as ClyA (a hemolysin), LeoA (a cytoplasmic protein with GTPase activity that is required for LT secretion), EatA (a serine protease autotransporter), enteroaggregative heat-stable toxin 1 (EAST-1) (a toxin that share 50% identity with the enterotoxigenic domain of heat-stable toxin and can also trigger the cGMP signal transduction pathway), and Tia and TibA (2 outer membrane proteins that mediate adhesion and invasion) (Del Canto et al, 2011;Gonzales et al, 2013;Rivera et al, 2013).…”

Escherichia coli heat-stable enterotoxins

“…Some E. coli strains isolated from outbreaks and sporadic cases of diarrhea in humans harbored no known virulence determinant other than EAST1 [196,[202][203][204][205][206][207].…”