High protease activity of Chryseobacterium indologenes isolates associated with invasive infection.

In order to understand virulence factors of Chryseobacterium indologenes isolates associated with invasive infection, enzymatic activities and cellular fatty acid profiles of 42 isolates recovered at National Taiwan University Hospital from January 1994 to December 1996 were studied. Among them, 12 blood isolates were considered as invasive and 30 (recovered from urine, sputa, infected burn wounds, and catheter tips) were noninvasive. All isolates showed strong activities of alkaline phosphatase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, and N-acetyl-beta-glucosaminidase, and had no activities for alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, and alpha-fucosidase. The activities of other enzymes were variable. Thirty-two isolates (76%) had varying degrees of protease activity. Two profiles (profiles I and II) of cellular fatty acids of the isolates were found and profile I predominated. There was no significant difference of distribution of cellular fatty acid profiles and activities of enzymes between invasive and noninvasive isolates, except protease activity which was significantly higher in invasive isolates than that in noninvasive isolates. Protease activity may play an important role in virulence on invasive infections caused by C. indologenes.