by Roberto M. Vidal, Khitam Muhsen, Sharon M. Tennant, Ann-Mari Svennerholm, Samba O. Sow, Dipika Sur, Anita K. M. Zaidi, Abu S. G. Faruque, Debasish Saha, Richard Adegbola, M. Jahangir Hossain, Pedro L. Alonso, Robert F. Breiman, Quique Bassat, Boubou Tamboura, Doh Sanogo, Uma Onwuchekwa, Byomkesh Manna, Thandavarayan Ramamurthy, Suman Kanungo, Shahnawaz Ahmed, Shahida Qureshi, Farheen Quadri, Anowar Hossain, Sumon K. Das, Martin Antonio, Inacio Mandomando, Tacilta Nhampossa, Sozinho Acácio, Richard Omore, John B. Ochieng, Joseph O. Oundo, Eric D. Mintz, Ciara E. O’Reilly, Lynette Y. Berkeley, Sofie Livio, Sandra Panchalingam, Dilruba Nasrin, Tamer H. Farag, Yukun Wu, Halvor Sommerfelt, Roy M. Robins-Browne, Felipe Del Canto, Tracy H. Hazen, David A. Rasko, Karen L. Kotloff, James P. Nataro, Myron M. Levine
Enterotoxigenic Escherichia coli (ETEC) encoding heat-stable enterotoxin (ST) alone or with heat-labile enterotoxin (LT) cause moderate-to-severe diarrhea (MSD) in developing country children. The Global Enteric Multicenter Study (GEMS) identified ETEC encoding ST among the top four enteropathogens. Since the GEMS objective was to provide evidence to guide development and implementation of enteric vaccines and other interventions to diminish diarrheal disease morbidity and mortality, we examined colonization factor (CF) prevalence among ETEC isolates from children age <5 years with MSD and from matched controls in four African and three Asian sites. We also assessed strength of association of specific CFs with MSD.
MSD cases enrolled at healthcare facilities over three years and matched controls were tested in a standardized manner for many enteropathogens. To identify ETEC, three E. coli colonies per child were tested by polymerase chain reaction (PCR) to detect genes encoding LT, ST; confirmed ETEC were examined by PCR for major CFs (Colonization Factor Antigen I [CFA/I] or Coli Surface [CS] antigens CS1-CS6) and minor CFs (CS7, CS12, CS13, CS14, CS17, CS18, CS19, CS20, CS21, CS30). ETEC from 806 cases had a single toxin/CF profile in three tested strains per child. Major CFs, components of multiple ETEC vaccine candidates, were detected in 66.0% of LT/ST and ST-only cases and were associated with MSD versus matched controls by conditional logistic regression (p≤0.006); major CFs detected in only 25.0% of LT-only cases weren’t associated with MSD. ETEC encoding exclusively CS14, identified among 19.9% of 291 ST-only and 1.5% of 259 LT/ST strains, were associated with MSD (p = 0.0011). No other minor CF exhibited prevalence ≥5% and significant association with MSD.
Major CF-based efficacious ETEC vaccines could potentially prevent up to 66% of pediatric MSD cases due to ST-encoding ETEC in developing countries; adding CS14 extends coverage to ~77%.
Tratto da: www.plos.org
Note sul Copyright: Articles and accompanying materials published by PLOS on the PLOS Sites, unless otherwise indicated, are licensed by the respective authors of such articles for use and distribution by you subject to citation of the original source in accordance with the Creative Commons Attribution (CC BY) license.