Microbiology Case Study: A 71 Year Old Man with a dehised Corneal Wound

Case History

A 71 year old man presented with a dehisced corneal wound status post corneal transplant.

Laboratory Diagnosis

Corneal scrapings from the ulcer were submitted for interpretation and two separate organisms were isolated from the blood agar plates. The first was a non-motile gram negative rod that grew on 5% horse blood agar and MaConkeys agar. The organism was oxidase negative and spot indole negative and was identified as Klebsiella pneumoniae.

The second organism grew in bright yellow-pigmented colonies on 5% horse blood agar (Image 1) but did not grow on MacConkeys. The organism was oxidase positive and spot indole positive and was identified as Chryseobacterium indologenes by MALDI.

Discussion

Chryseobacterium indologenes, previously known as Flavobacterium indologenes is a yellow pigmented, gram-negative filamentous, non-motile rod that is a non-glucose fermenter and can be found in soil, plants, foodstuffs and water sources including those found in hospitals. It produces a water-insoluble pigment, flexirubin which gives it its characteristic color. It was first isolated from a clinical specimen in 1983 however there have been more recent reports of bacteremia related to C. indologenes related to use of indwelling devices, such as a catheters.

1. indologenes typically exhibits resistance to multiple antibiotics, however, a case series of 16 patients with C. indologenes infections, all nosocomial and in patients with comorbidities, showed no clear relationship between antibiotic susceptibility and response to treatment (1).

Reference:

1. Lin Y-T, Jeng Y-Y, Lin M-L, Yu K-W, Wang F-D, Liu C-L. 2010. Clinical and Microbiological Characteristics of Chryseobacterium indologenes Bacteremia. J. Microbiol. Immunol. Infection.43:498-505.

-Agnes Balla, MD is a 3^rd year anatomic and clinical pathology resident at the University of Vermont Medical Center.

-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Assistant Professor at the University of Vermont.