DETECTION OF LOW-LEVELS OF SPECIFIC SALMONELLA SPECIES BY FLUORESCENT-ANTIBODIES AND FLOW-CYTOMETRY

The use of fluorescently-labelled monoclonal antibodies, with detectio n by multi-parameter flow cytometry, was investigated for the rapid de tection of salmonellas in pure cultures. Accurate detection of specifi c Salmonella serotypes was demonstrated down to levels of below 10(4) cells ml(-1) (within 30 min) and 1 cell ml(-1) (after 6 h non-selectiv e pre-enrichment). This level of sensitivity was attained even in the presence of high levels of other bacterial species that would otherwis e have interfered with the results. With combinations of different ant ibodies, each with a unique fluorescent label, simultaneous analysis f or two species was possible.