title: Occurrence of HybridEscherichia coliStrains Carrying Shiga Toxin and Heat-Stable Toxin in Livestock of Bangladesh.
abstract: Shiga toxin-producingEscherichia coli(STEC) and enterotoxigenicE. coli(ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study,E. colistrains (n= 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%)E. colistrains to be virulent possessing eithersta(n= 5),stx(stx1,n= 8;stx2,n= 2), or both (n= 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried bothstx(eitherstx1 orstx2) and ETEC-specific enterotoxin genesta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36:H5, O174:H-, O152:H8, O109:H51, and O8:H21, while the STEC-producing strains belonged to serotypes O76:H19 (n= 3), O43:H2 (n= 2), O87:H16 (n= 2), OR:H2 (n= 1), O110:H16 (n= 1), and O152:H8 (n= 1). The STEC-ETEC hybrid strains belonged to serotypes O76:H19 (n= 3), O43:H2 (n= 2), O87:H16, OR:H2, and O152:H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistantE. coliSTEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Fatema-Tuz
authors.initials: FT
authors.lastname: Johura
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Rozina
authors.initials: R
authors.lastname: Parveen
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Atiqul
authors.initials: A
authors.lastname: Islam
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Abdus
authors.initials: A
authors.lastname: Sadique
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Md Niaz
authors.initials: MN
authors.lastname: Rahim
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Shirajum
authors.initials: S
authors.lastname: Monira
authors.affiliation: Department of Microbiology, University of Dhaka , Dhaka , Bangladesh.
authors.forename: Anisur R
authors.initials: AR
authors.lastname: Khan
authors.affiliation: Department of Microbiology, University of Dhaka , Dhaka , Bangladesh.
authors.forename: Sunjukta
authors.initials: S
authors.lastname: Ahsan
authors.affiliation: National Institute of Infectious Diseases , Tokyo , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohnishi
authors.affiliation: National Institute of Infectious Diseases , Tokyo , Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Johns Hopkins Bloomberg School of Public Health , Baltimore, MD , USA.
authors.forename: Subhra
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Johns Hopkins Bloomberg School of Public Health , Baltimore, MD , USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: George
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cravioto
authors.affiliation: Department of Public Health, Faculty of Medicine, Universidad Nacional Autónoma de Mexico , Mexico City , Mexico.
authors.forename: Armando
authors.initials: A
authors.lastname: Navarro
authors.affiliation: Infectious Disease, Department of Medical Sciences, Uppsala University , Uppsala , Sweden.
authors.forename: Badrul
authors.initials: B
authors.lastname: Hasan
authors.affiliation: International Center for Diarrheal Disease Research, Bangladesh (icddr,b) , Dhaka , Bangladesh.
authors.forename: Munirul
authors.initials: M
authors.lastname: Alam
keywords: PFGE; Shiga-toxin; enterotoxin; hybrid; livestock; multidrug resistant