Detection of colonization factor antigen I-positive enterotoxigenic Escherichia coli with a cloned polynucleotide probe.
We compared a new colony hybridization assay with an established enzyme-linked immunosorbent assay for detection of enterotoxigenic Escherichia coli (ETEC) expressing colonization factor antigen I (CFA/I). The tests were applied to 135 human ETEC strains. Of these isolates, 30 had previously been characterized for CFAs. A strain harboring the plasmid vector of the polynucleotide gene probe, nine non-ETEC strains from healthy infants, and eight ETEC strains of animal origin were included for further evaluation of probe specificity. The two assays showed a high level of concordance in the specific detection of ETEC strains expressing CFA/I. A total of 24 strains tested positive in the CFA/I hybridization assay, while 23 of those strains were positive in the CFA/I enzyme-linked immunosorbent assay. The single discrepant result could be explained by the loss of a regulatory gene. The strain harboring the plasmid vector of the probe, the non-ETEC E. coli strains, and the ETEC strains of animal origin were all negative in the CFA/I probe assay.
Grewal
H M
HM
Institute of International Health and Medical Department B, Haukeland Hospital, Bergen, Norway.
Sommerfelt
H
H
Gaastra
W
W
Svennerholm
A M
AM
Bhan
M K
MK
Hamers
A M
AM
Kumar
R
R
Wiklund
G
G
Bjorvatn
B
B
D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism; D015342:DNA Probes; D004768:Enterotoxins / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D005069:Evaluation Studies as Topic; D036781:Fimbriae Proteins; D006801:Humans; D009693:Nucleic Acid Hybridization
D000942:Antigens, Bacterial; D015342:DNA Probes; D004768:Enterotoxins; C022924:colonization factor antigens; D036781:Fimbriae Proteins