A rapid method to determine bacterial contamination on hatching eggs. 3. Use of commercial DNA probe kits for detection of specific pathogens after six hours of incubation.
The usefulness of commercially available DNA probe kits for the detection of Escherichia coli and Salmonella spp. after only 6 h of incubation, was determined. It was established that the commercially available probe kits used could detect E. coli at initial levels of approximately 4.5 x 10(2) colony-forming units (cfu) per ml after only 6 h of incubation in nutrient broth (NB). Initial bacterial levels as low as 4.5 x 10(1) cfu/ml could be detected when the NB was incubated for 18 h. Salmonella Enteritidis, at initial levels of 2.86 x 10(2) cfu/ml could be detected after 6 h of incubation at 37 degrees C in NB, while initial levels as low as 2.86 x 10(-1) cfu/ml could be detected after 18 h at 37 degrees C in both NB and selected media, as specified by the manufacturers of the probe kits. Commercially available DNA probe kits can therefore be used to detect specific pathogens on the surface of hatching eggs and these probes can be used in conjunction with an egg-washing system, which is used to determine total bacterial contamination, although a longer incubation period greatly improves the sensitivity of these tests.
Department of Poultry Diseases, Faculty of Veterinary Science University of Pretoria, Onderstepoorf, South Africa.
A C
AC
Pienaar
L
L
Coetzee
R R
RR
Bragg
D000818:Animals; D002645:Chickens / Q000382:microbiology*; D015342:DNA Probes; D004531:Eggs / Q000382:microbiology*; D004926:Escherichia coli / Q000302:isolation & purification*; D005069:Evaluation Studies as Topic; D011933:Reagent Kits, Diagnostic; D012477:Salmonella enteritidis / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
D015342:DNA Probes; D011933:Reagent Kits, Diagnostic