Identification of emerging Chryseobacterium indologenes sepsis using automated identification system, Matrix-assisted Laser Desorption Ionization-time-of-flight Mass Spectrometry (MALDI-TOF) and Pulsed-field Gel Electrophoresis (PFGE) typing

Chryseobacterium indologenes is a non-motile, catalase-positive, oxidase-positive, indole-positive, non-glucose-fermenting Gram-negative bacillus that produces yellow coloured colonies on routine culture media. As common environmental saprobe, it is a known colonizer of inanimate objects in the hospital environment. Chryseobacterium indologenes is an emerging .pathogen of nosocomial origin in background of increased use of higher antibiotics. In the present study, positive blood cultures bottled from critically ill patients suspected of nosocomial sepsis were inoculated on routine bacteriological media for a period of six months. The identity and antibiotic sensitivity of Chryseobacterium indologenes were confirmed by Phoenix automated system® followed by automated MALDI-TOF system and Pulsed Field Gel Electrophoresis (PFGE) typing. All the patients had underlying morbidities (7 out of 7 patients). Phoenix automated system and MALDI-TOF system correctly identified the bacterial isolates. We reiterate the fact that levofloxacin should be the first choice of antibiotic in Chyrseobacterium indologens infections followed by cefoperazone + sulbactam. All the isolates were of different clonality as determined by PFGE. To our knowledge, this is the first report on the identification of Chrysobacterium indologenes isolates using automated system, MALDI-TOF and PFGE in India. So, in ICUs of tertiary care centers, where higher antibiotics are used, this bacteria can be an important cause of nosocomial bacteremia. Keywords: Chryseobacterium indologenes, sepsis, MALDI-TOF, PFGE, Phoenix automated system