title: Lineages and virulence gene content among extended-spectrum β-lactamase-producing Escherichia coli strains of food origin in Tunisia.
abstract: Nineteen extended-spectrum β-lactamase (ESBL)-positive Escherichia coli strains recovered from food samples in Tunisia were characterized by multilocus sequence typing and phylogenetic typing, and the virulence gene and plasmid content were also determined. These strains  presented unrelated pulsed-field gel electrophoresis patterns and contained genes coding for the following ESBLs (the number of strains is in parentheses): CTX-M-1 (15), CTX-M-14 (2), CTX-M-8 (1), and SHV-5 (1). Twelve different sequence types (STs) were identified among the 19 ESBL-positive  strains, which included two new STs (ST2022 in 2 bla(CTX-M-14)-containing strains and ST1970 in 2 bla(CTX-M-1)-containing strains). ST155 and ST602 were detected in four and three bla(CTX-M-1)-containing strains, respectively,  and ST405 was detected in one bla(CTX-M-8)-producing strain. All ESBL-positive strains were ascribed to the phylogenetic groups A and B1. Most of the bla(CTX-M-1)-containing strains harbored an IncI1 plasmid, except for the four bla(CTX-M-1)-positive  strains of beef origin and ST155, which harbored an IncN plasmid. The two bla(CTX-M-14)-containing strains contained an IncI1 plasmid. The virulence gene fimA was detected in all strains. Most strains also carried the aer gene, and six strains carried the  eae gene. All strains were negative for the virulence genes sxt, papG-III, papC, hly, cnf1, and bfp. We conclude that ESBL-producing E. coli strains of food origin in Tunisia show high diversity and that plasmids harboring ESBL genes could be implicated in  the dissemination of this resistance phenotype.
authors: Laboratoire Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Université Tunis-El Manar, 2092 Tunis, Tunisia.
authors: Ahlem
authors: A
authors: Jouini
authors: Karim Ben
authors: KB
authors: Slama
authors: Naouel
authors: N
authors: Klibi
authors: Rym Ben
authors: RB
authors: Sallem
authors: Vanesa
authors: V
authors: Estepa
authors: Laura
authors: L
authors: Vinué
authors: Yolanda
authors: Y
authors: Sáenz
authors: Fernanda
authors: F
authors: Ruiz-Larrea
authors: Abdellatif
authors: A
authors: Boudabous
authors: Carmen
authors: C
authors: Torres
mesh_terms: D000818:Animals; D002417:Cattle; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology / Q000235:genetics; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids; D014416:Tunisia; D037521:Virulence Factors / Q000235:genetics*; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D037521:Virulence Factors; D001618:beta-Lactamases