Identification and Clinical Significance of Kluyvera species

Lee, Woo Chang; Yun, Kyung A; Kim, Mi Na; Pai, Chik Hyun

Abstract

BACKGROUND: Kluyvera, a new genus in the family Enterobacteriaceae, has been rarely isolated from clinical specimens and regarded as an opportunistic pathogen. Although there were several case reports in Korea, most of them were reported at a genus level except a case of K. cyrocrescens. We isolated Kluyvera species from seven patients from July 1996 to January 1999. We identified them to species level and investigated their clinical significance.
METHODS
The medical records of seven patients were reviewed for demographical findings, underlying diseases, diagnoses, the association of Kluyvera isolates with disease, antibiotic treatments, and clinical outcomes. Eight strains were identified and tested for the antimicrobial susceptibilities by MicroScan Neg Combo type 14 and 21 Panel(Dade Behring, USA). Five of the eight strains had been stored at -70degrees C and were tested for ascorbate fermentation, the ability to grow and ferment glucose at 5degrees C, and the zone of inhibition around carbenicillin and cephalothin.
RESULTS
Kluyvera isolates were regarded as true pathogens in six of seven cases including Hickman-catheter associated sepsis(HCAS), empyema, peritonitis, necrotizing cholecystitis, sepsis, and liver abscess although the latter four cases yielded mixed cultures. While three of the six patients had underlying diseases, malignant lymphoma, hepatocellular carcinoma and stomach cancer, other three were previousely healthy. Most of them were improved with an empirical therapy, but Kluyvera species was repeatedly isolated from the HCAS case in spite of the antibiotic treatment; it was cured bacteriologically after the removal of the catheter. The five isolates were all confirmed to be K. ascorbata by positive ascorbate test, and failure to grow at 5degrees C.
CONCLUSIONS
Six of the seven cases including three with no underlying diseases, isolates of Kluyvera species were found clinically significant, suggesting that Kluyvera species is potentially pathogenic in healthy individuals as well as compromized hosts. MicroScan system is capable of identifying Kluyvera species at the genus level, but not at the species level. The ascorbate test is simple and useful for differ entiation of K. ascorbata from K. cryocrescens.