Figure 5

Two-step algorithm for the rapid identification and differentiation of Francisella strains using fluorescence in situ hybridization. After an initial hybridization step with three probes including the "pan-Francisella" probe Bw-all1488, negative samples can directly be reported. Performing internal controls with probe EUB-338 allows recognizing false negative results caused by technical problems. After hybridization with all species- and subspecies-specific probes in parallel, initially positive samples can be further differentiated by following the algorithm depicted in step two allowing unambiguous identification to subspecies level.