RELATIONSHIP BETWEEN INDOLE PRODUCTION AND DIFFERENTIATION OF KLEBSIELLA SPECIES - INDOLE-POSITIVE AND INDOLE-NEGATIVE ISOLATES OF KLEBSIELLA DETERMINED TO BE CLONAL

Klebsiellae are an important cause of nosocomial infections. The two c linically relevant species, Klebsiella pneumoniae and Klebsiella oxyto ca, are differentiated by the ability to produce indole from tryptopha n, K. oxytoca being indole positive. We report here the detailed bioch emical and molecular analysis of two isolates of Klebsiella, cultured from the same urine specimen, that differed only in their ability to p roduce indole. The two isolates were identical as determined by riboty ping and pulsed-field gel electrophoresis, and they differed from 10 e pidemiologically unrelated strains. Probing with the Escherichia coli tryptophanase operon, tna, revealed seven restriction fragment length polymorphisms (RFLP) among the 12 strains. The two index strains had i dentical RFLP; no single RFLP could account for all of the indole-posi tive or -negative strains. Thus, the identification of epidemiological ly related strains of Klebsiella differing only in indole production m ay warrant further examination to determine whether the strains are cl onal.