Identification of Leishmania spp. by radiorespirometry

Preliminary investigation of the application of radiorespirometric technic to protozoan parasites of man indicates a potential for rapid identification. This technic, developed for identification of bacteria, was modified for use with culture forms of Leishmania. Five strains of Leishmania were compared: 2 of L. donovani, 2S and K; L. brasilensis, 2936 and B; and 1 of L. tropica, A. Consisent and rapid (approximately 2 hr) identification was obtained by the radiorespirometric procedure. A computer-type analysis of the radiorespirometric profiles of the 5 strains permitted correct identification of each isolate at the strain level 100% of the time. This technic offers several advantages over many current procedures for identification of protozoan parasites: (A) It is simple, rapid and highly reproducible, (B) Since it does not rely on visual or spectrophotometric determination, it may be conducted in the presence of optically complex substances. (C) It requires relatively low numbers of organisms (approximately 2 x 10(5)/14C-labeled substrate). (D) It is based on differential enzymic activity between species and strains of organisms and therefore, ultimately, on inherent genetic determinates of the parasites. (E) Further development of the procedure and accumulation of a data reference "bank" would allow automation of most of the identification process.