[Isolation of Neisseria elongata subsp. elongata Isolated from an Acute Myelogenous Leukemia Patient].

Gram-negative cocci with a rod-like shape were isolated from a blood sample of a patient with acute myelogenous leukemia (AML). The 16S rRNA sequence of the isolate was similar to that of Neisseria elongata. Because previous reports about N. elongata as a pathogen have been extremely rare, more reliable identification seemed to be needed. We thus additionally performed a Multilocus Sequencing Analysis (MLSA) based on another four regions (argF, rho, recA, glnA), and confirmed the identification of N. elongata. The results from the MLSA identified the species; however, we could not identify the isolates into subspecies from the sequences. Three subspecies of N. elongata (N. elongata subsp. elongata, N. elongata subsp. glycolytica and N. elongata subsp. nitroreducens) were classified based on three definitive characteristics (catalase possession, nitrite reducibility, and acid from glucose). The results of the tests of three characteristics supported the identification of the isolate as N. elongata subsp. elongata. Therefore we determined the isolate from the AML patient to be N. elongata subsp. elongata.