Biofilm formation, invasiveness and colicinogeny in locus of enterocyte and effacement negative O113:H21 Shigatoxigenic Escherichia coli.
OBJECTIVE
Although Shiga toxins (Stx) are well-established virulence traits of O113:H21 Shigatoxigenic Escherichia coli (STEC) strains, a shortage in the knowledge of other virulence properties that may contribute to pathogenesis may exist in this serotype. This study investigated biofilm, invasiveness and colicinogeny capabilities in O113:H21 STEC isolated in Brazil, mostly from animal reservoirs. A search for genes that were reported to participate in the process of biofilm formation was also performed.


RESULTS
The 34 O113:H21 STEC isolates analysed were assayed for biofilm production in polystyrene microplates. Genes for biofilm were investigated by PCR. Invasion of cell lineages was assessed in gentamicin protection assays and colicinogeny was investigated by phenotypic tests. Fifty per cent of the strains were biofilm formers, and 35% exhibited an invasive behaviour. The pattern of distribution of biofilm-related genes did not correlate with biofilm phenotypes observed, and a high percentage of the investigated strains were able to secrete colicins.


CONCLUSIONS
Ability to form biofilm, invasiveness and colicinogeny is demonstrated for the first time in a collection of O113:H21 STEC.


CONCLUSIONS
The ability to express three additional phenotypes besides Stx production may be a factor influencing the pathogenicity and persistence potential of O113:H21 STEC.
Adolfo Lutz Institute, Center of Bacteriology, Sao Paulo, Brazil.|Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil.
L F
LF
Dos Santos
Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil.
F T
FT
Biscola
Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil.
E M
EM
Gonçalves
Department of Microbiology, Immunology and Parasitology, Federal University of Sao Paulo, Sao Paulo, Brazil.
B E C
BE
Guth
D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D018938:Caco-2 Cells; D002460:Cell Line; D003087:Colicins / Q000378:metabolism; D006801:Humans; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D014774:Virulence
D003087:Colicins
O113:H21; Shigatoxigenic Escherichia coli; biofilm; colicinogeny; invasiveness