Evaluation of DNA-DNA hybridization for the direct detection of enterotoxigenic Escherichia coli in stool blots.
The simplicity of enterotoxigenic Escherichia coli (ETEC) stool blot hybridization, where the total bacterial growth of a fecal inoculum is examined directly for the presence of enterotoxin genes, has been marred by reports of unsatisfactory sensitivity and/or specificity. To assess the accuracy of stool blot hybridization and to study the effect of varying proportions of ETEC among fecal E. coli (ETEC/E. coli) on test performance, a detailed 'blind' study of 166 stool specimens from children with diarrhea was performed. Oligonucleotide probes were found to be superior to polynucleotide probes, having a sensitivity of 80%, a specificity of 99%, a positive predictive value of 89% and a negative predictive value of 97%. The sensitivity was found to be 100% when ETEC/E. coli > 2/12, as compared with 20% when ETEC/E. coli < or = 2/12 (p = 0.001), showing that the proportion of ETEC among fecal E. coli is of paramount importance for test sensitivity.
Sommerfelt
H
H
Centre for International Health, University of Bergen, Haukeland Hospital, Norway.
Bhan
M K
MK
Srivastava
R
R
Bhatnagar
S
S
D001431:Bacteriological Techniques / Q000706:statistics & numerical data; D002648:Child; D015342:DNA Probes; D004269:DNA, Bacterial / Q000302:isolation & purification*; D003951:Diagnostic Errors; D003967:Diarrhea / Q000382:microbiology; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000302:isolation & purification* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000382:microbiology; D005069:Evaluation Studies as Topic; D005243:Feces / Q000382:microbiology*; D006801:Humans; D009693:Nucleic Acid Hybridization / Q000379:methods* / Q000706:statistics & numerical data; D015345:Oligonucleotide Probes; D012680:Sensitivity and Specificity
D015342:DNA Probes; D004269:DNA, Bacterial; D004768:Enterotoxins; D015345:Oligonucleotide Probes