Chryseobacterium

Chryseobacterium is a genus of Gram-negative, non-spore-forming, rod-shaped bacteria in the family Weeksellaceae, order Flavobacteriales. Members are aerobic and oxidase-positive non-fermenters that typically produce yellow pigmented colonies due to flexirubin-type pigments, giving a characteristic golden color. The type species is Chryseobacterium indologenes; other commonly encountered species include C. gleum and C. balustinum. These bacteria are frequently environmental, found in soil, freshwater, and plant-associated habitats worldwide.

In addition to environmental isolates, Chryseobacterium species are occasionally recovered from clinical specimens and hospital water systems. Identification in clinical laboratories can be challenging because of resemblance to other non-fermenters; MALDI-TOF mass spectrometry and 16S rRNA sequencing are often used for accurate identification. They are typically non-spore-forming and capable of surviving in moist, nutrient-limited settings such as medical devices and plumbing.

Clinically, Chryseobacterium spp. are opportunistic pathogens, most commonly affecting immunocompromised or hospitalized patients. Infections reported include bacteremia, pneumonia, skin and soft tissue infections, urinary tract infections, and, less frequently, meningitis. Outbreaks have been linked to contaminated water sources. Many species exhibit intrinsic resistance to multiple antibiotics, so treatment is guided by susceptibility testing; some isolates may be susceptible to fluoroquinolones, trimethoprim-sulfamethoxazole, or certain beta-lactam combinations, depending on the strain.