Probes for Identifying Listeria-Reply

In Reply.—  Dr Datta is correct that his article¹ reports a probe specific for L monocytogenes using a colony hybridization assay under less than stringent hybridization conditions. However, Dr Flamm, who initially developed and assessed the clone from which this probe was derived, reports in his thesis that the probe reacts with chromosomal DNA restriction fragments of L monocytogenes, Listeria innocua, Listeria ivanovii, and Listeria seeligeri.² We studied the same putative β-hemolysin gene fragment cloned by Dr Flamm and showed that specific hybridization with L monocytogenes occurs only if the hybridization is performed at highly stringent conditions. Further, we found that the fragment hybridizes to one of seven strains of L seeligeri, even under stringent hybridization conditions.³Subsequently, probes have been developed based on the sequence of listeriolysin that seem to be specific for L monocytogenes. We look forward to evaluation of these probes in the detection