Alkaline phosphatase-conjugated oligonucleotide probes for enterotoxigenic Escherichia coli in travelers to South America and West Africa.
Several studies have demonstrated the usefulness of 32P-labeled recombinant DNA probes for identifying enterotoxigenic Escherichia coli (ETEC). The use of radioisotopes and X-ray development, however, severely handicaps the utility of DNA probes in most clinical laboratories. In this study, enzyme-labeled oligonucleotide probes for ETEC LT (heat-labile toxin) and ST (heat-stable toxin) genes were compared with the standard Y1 adrenal cell and suckling mouse assays for their ability to identify ETEC in a population of American adults experiencing acute episodes of diarrhea in South America and West Africa. The LT probe hybridized with 12% (64 of 529) of the E. coli colonies tested, whereas 11% (57 of 529) were positive by Y1 adrenal cell assay. DNA from 9% (47 of 529) of the E. coli colonies tested hybridized with the ST probe, whereas only 5% (28 of 529) produced ST as measured by the suckling mouse bioassay. For the patient samples tested, correlation between probe and bioassay for LT was 97%, or three discrepancies in 111 patients tested. Overall concordance of the ST probe and bioassay was 95%, or five discrepancies in 111 patients. Enzyme-labeled oligonucleotide probes represent a major advance in the diagnosis of ETEC-associated diarrheal disease and may be used in laboratories with minimal equipment.
Oprandy
J J
JJ
Infectious Diseases Department, Naval Medical Research Institute, Bethesda, Maryland 20814.
Thornton
S A
SA
Gardiner
C H
CH
Burr
D
D
Batchelor
R
R
Bourgeois
A L
AL
D000328:Adult; D000354:Africa, Western; D000469:Alkaline Phosphatase; D001427:Bacterial Toxins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D001681:Biological Assay; D004274:DNA, Recombinant; D003967:Diarrhea / Q000175:diagnosis* / Q000382:microbiology; D004768:Enterotoxins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D029968:Escherichia coli Proteins; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization; D009838:Oligodeoxyribonucleotides; D013020:South America; D014195:Travel
D001427:Bacterial Toxins; D004274:DNA, Recombinant; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; C034151:heat stable toxin (E coli); C027538:heat-labile enterotoxin, E coli; D000469:Alkaline Phosphatase