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

Abstract

Abstract. Enterotoxigenic Escherichia coli (ETEC) can be attributed to around 200 million diarrheal episodes and 380,000 deaths in the developing regions. Travelers' diarrhea occurs in 15-40% of travelers to developing regions with ETEC being the most important etiologic agent. This study aims to describe the distribution of enterotoxins and colonization factor (CF) profiles of ETEC isolates from stool samples of adult travelers acquiring diarrhea in Mexico, Guatemala, and India and a group of children with acute diarrhea in Houston, TX, between 2007 and 2012. The heat-labile/heat-stable (LT/ST) enterotoxins and CFs from 252 patients were determined using polymerase chain reaction assay. Among the 252 ETEC isolates, 15% were LT-only, 58% were ST-only, and 28% produced both LT and ST. The distribution of LT-only (12-15%) and ST-only (55-56%) isolates was similar between Latin American and Indian sites. The most prevalent CF was CS21, expressed in 65% of the isolates followed by CS6 (25%) and CS3 (17%). Among the international travelers, 64% of the ETEC isolates expressed CS21. CS21 was expressed in 46% of isolates from Latin America compared with 96% of isolates from India (P < 0.0001). CS21 was expressed in 85% isolates from Houston children. CS21 was increasingly found in ST-only (P = 0.003) and ST/LT (P = 0.026) ETEC compared with LT-only ETEC. High frequency of finding CS21 among recent isolates of ETEC over a wide geographic distribution warrants additional studies on this CF. Highly conserved CS21 is an important target for potential multivalent ETEC vaccines.

Impact of Rotavirus Vaccine Introduction and Postintroduction Etiology of Diarrhea Requiring Hospital Admission in Haydom, Tanzania, a Rural African Setting

“…In this study, Shigella , ST-ETEC, and Cryptosporidium were also important etiologies of diarrhea requiring hospitalization and are potential targets for further reduction in diarrhea burden with pathogen-specific interventions. The ST-ETEC colonization factor profile in this study is consistent with prior data suggesting that CFA/1, CS3, CS5, and CS6 account for a majority of all CF-positive clinical ETEC isolates and that CS21 is emerging as a colonization factor of global importance [ 40–42 ]. Because CS21 and CFA/1 were frequently codetected, current ETEC vaccine candidates that target CFA/I, CS3, CS4, CS5, and CS6 would still be predicted to cover 80% of the diarrhea-associated ETEC in this study.…”

Biochemical and Immunological Evaluation of Recombinant CS6-Derived Subunit Enterotoxigenic Escherichia coli Vaccine Candidates

“…CS6 is a prevalent CF expressed by ETEC strains and is of special interest for a multivalent ETEC vaccine approach, as it is found globally in approximately 20% of clinically isolated ETEC strains (13,22). CS6 is a polymeric structure consisting of two major structural subunits, CssA and CssB, with both having potential host intestinal binding activities (24,25).…”

“…Seven CFs, CFA/I and CS1 to CS6, are more prevalent in clinical isolates, and a vaccine comprised of these CFs and an LT toxin component could potentially provide coverage against 80% of global ETEC strains (12). Of the seven above-mentioned CFs, CS6 is an attractive vaccine target, as it is highly prevalent, expressed alone or with additional CFs in approximately 20% of clinical isolates globally (12)(13)(14). However, past efforts to develop a vaccine using purified, recombinant CS6 antigen (Ag) administered via the transcutaneous route or microencapsulated and administered via the oral route have been unsuccessful (15-17; D. Tribble, unpublished data).…”

Engineered Microbes to Sense and Respond to Enterotoxigenic Escherichia coli

“…Enterotoxigenic E. coli (ETEC) is the leading known cause of Traveler's Stomach for both deployed military personnel and civilian travelers. ETEC is the most common toxic form of Traveler's Stomach for deployed personnel and produces two toxins, heat labile and heat stable [5].…”

“…As countries continue to develop, ETEC remains present in communities, affecting many civilians in the community that are not native to the area. [5]. 1 Removing genes from one plasmid and inserting them into another resembles a form of plug and play.…”