The use of alkaline phosphatase-labelled oligonucleotide probes as culture confirmation reagents for identification of commercially important bacteria.

A range of rRNA-targeted alkaline phosphatase labelled oligonucleotide probes was tested for use as culture confirmation reagents for the rapid identification of micro-organisms. The probes were specific to clinically important bacteria (Helicobacter pylori and Mycobacterium tuberculosis), fish and shellfish pathogens (Renibacterium salmoninarum and Vibrio vulnificus), food spoilage bacteria (Listeria spp. and L. monocytogenes), for bacteria of biotechnological importance (Streptomyces spp.) and for bacteria associated with the oil industry (Sulphate-reducing bacteria, SRB). A universal bacterial probe and a eukaryotic probe were included in the study as positive and negative controls, respectively. A total of 93 bacterial strains was screened. With the exception of a large number of cross-reactions of the SRB probe (specificity value of 29.4%) and a single cross-reaction of the R. salmoninarum probe (specificity value of 97.7%), dot blot analysis indicated that each probe hybridized 100% specifically to the organisms tested. A simple culture confirmation method was then developed using these probes to enable the identification of bacterial colonies using a simple hybridization procedure.