Differentiation of typical and atypical enteropathogenic Escherichia coli using colony immunoblot for detection of bundle-forming pilus expression.
OBJECTIVE
The aim of study was to develop a colony immunoblot assay to differentiate typical from atypical enteropathogenic Escherichia coli (EPEC) by detection of bundle-forming pilus (BFP) expression.


RESULTS
Anti-BFP antiserum was raised in rabbits and its reactivity was confirmed by immunoelectron microscopy and by immunoblotting recognizing bundlin, the major pilus repeating subunit. The bacterial isolates tested in the colony immunoblot assay were grown in different media. Proteins from bacterial isolates were transferred to nitrocellulose membrane after treatment with phosphate buffer containing Triton X-100, EDTA and sodium chloride salts. When 24 typical EPEC and 96 isolates including, 72 atypical EPEC, 13 Gram-negative type IV-expressing strains and 11 enterobacteriaceae were cultivated in Dulbecco's Modified Eagle's Medium agar containing fetal bovine serum or in blood agar in the presence of CaCl(2) , they showed a positivity of 92 and 83%, and specificity of 96 and 97%, respectively.


CONCLUSIONS
The assay enables reliable identification of BFP-expressing isolates and contributes to the differentiation of typical and atypical EPEC.


CONCLUSIONS
The colony immunoblot for BFP detection developed in this study combines the simplicity of an immunoserological assay with the high efficiency of testing a large number of EPEC colonies.
Nara
J M
JM
Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brazil.
Cianciarullo
A M
AM
Culler
H F
HF
Bueris
V
V
Horton
D S P Q
DS
Menezes
M A
MA
Franzolin
M R
MR
Elias
W P
WP
Piazza
R M F
RM
D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods*; D054308:Enteropathogenic Escherichia coli / Q000145:classification* / Q000302:isolation & purification; D010861:Fimbriae, Bacterial / Q000737:chemistry*; D015151:Immunoblotting / Q000379:methods*; D011817:Rabbits