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Não fermentadores

Chryseobacterium indologenes

Long, thin Gram-negative bacilli

Identification & Growth

Identification

  • Yellow pigment, oxidase-positive, indole-positive (weak, read with Ehrlich reagent)

Growth Conditions

  • Blood agar, 30–35 °C, 48 h; grows poorly on MacConkey

Clinical Significance

  • Ventilator-associated pneumonia, catheter-related bacteremia, ICU infection

Intrinsic Resistance

  • Chromosomal metallo-beta-lactamase: carbapenems inactive; polymyxins and aminoglycosides also ineffective

Bench Alerts

  • Carbapenem- and colistin-resistant yellow non-fermenter: think Chryseobacterium/Elizabethkingia
  • MIC-guided therapy; trimethoprim-sulfamethoxazole and minocycline are the usual options

Clinical Notes

Clinical presentations

  • Catheter-associated bacteremia and ventilator-associated pneumonia in intensive care patients.
  • Surgical wound infection, catheter-associated urinary infection and peritoneal dialysis peritonitis.
  • Keratitis and endophthalmitis after ophthalmic procedures or use of contaminated solutions.

Specimens and collection

  • Blood culture, tracheal aspirate, peritoneal fluid or ocular material according to the clinical focus.
  • Collect water, humidifier and solution samples during investigation of clustered cases.
  • Always assess the presence of an invasive device before assigning clinical significance to the isolate.

Epidemiology and at-risk populations

  • Environmental organism of soil and water; it survives in hospital water systems and aqueous solutions.
  • Infections are almost always healthcare-associated and linked to long-dwelling devices.
  • Immunosuppression, mechanical ventilation and prior broad-spectrum therapy are the dominant risk factors.

Resistance and therapeutic implications

  • It produces a metallo-beta-lactamase (IND): usual resistance to carbapenems and broad-spectrum cephalosporins.
  • Intrinsic resistance to colistin and aminoglycosides, invalidating the usual empirical regimen for non-fermenters.
  • More frequently active options: trimethoprim-sulfamethoxazole, fluoroquinolones, minocycline and piperacillin-tazobactam, always by MIC.

Bench and reporting notes

  • Non-fermenting Gram-negative rod, oxidase-positive, indole-positive and producing a yellow (flexirubin) pigment.
  • Variable growth on MacConkey; confirm identification by MALDI-TOF, since biochemical systems often err.
  • Flag in the report that there are no specific EUCAST/BrCAST criteria and state the interpretation method used.

Sources

Educational decision-support content. It does not replace laboratory validation, current guidelines or review by the responsible professional.

FAQ: Frequently Asked Questions

How to identify Chryseobacterium indologenes in the lab?

Chryseobacterium indologenes is identified through yellow pigment, oxidase-positive, indole-positive (weak, read with ehrlich reagent).

What are the intrinsic resistances of Chryseobacterium indologenes?

This organism is naturally resistant to chromosomal metallo-beta-lactamase: carbapenems inactive; polymyxins and aminoglycosides also ineffective. These drugs should not be reported as susceptible.

Where is Chryseobacterium indologenes commonly found?

It is typically associated with ventilator-associated pneumonia, catheter-related bacteremia, icu infection.

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