To the Editor:

Chryseobacteria are a group of gram-negative, non-fermenting, non-motile, catalase, oxidase and indole positive aerobic bacilli. C. meningosepticum is the most pathogenic, while C. indologenes is the most common, and is generally isolated in immunocompromised patients.1,2

We report the case of an 86-year-old female with insulin-dependent type 2 diabetes, of over 20 years’ progression, with diabetic nephropathy and retinopathy, high blood pressure, also with long progression and obesity. Stage 4 chronic kidney disease, with non-nephrotic proteinuria. Urinary infection due to E. coli in April 2010. She was admitted to hospital due to symptoms of decompensated congestive heart failure, associated with worsening of renal failure, sacral oedema and probable respiratory infection. She was started on diuretic and fluid management. Urine culture was performed and an increase of >100,000CFU/ml of ESBL carrying Escherichia coli and Chryseobacterium indologenes are found. The patient was being treated empirically with levofloxacin (with doses adjusted according to renal function) and did not display fever or haemodynamic instability, with a good clinical progression and a return to her baseline creatinine figures.

Chryseobacterium indologenes is found in soil, plants, food, fresh water, salt water and drinking water (it resists chlorination), but despite its extensive distribution in nature, it is not a part of the normal human microflora. In hospitals, it is isolated in water systems and surfaces of equipment and humid medical supplies (ventilators, tubes, humidifiers and others).2 It is not very pathogenic, although it forms a biofilm and produces a protease that may be important in its virulence.3,4 In vitro, its colony is circular, smooth, mucous and 1-2mm in diameter. The study of susceptibility is not standardised, and as such, antibiograms should be performed by dilution. It produces a metallo-β-lactamase that provides resistance to carbapenems. The most effective antimicrobials are levofloxacin, trimethoprim/sulfamethoxazole and piperacillin/tazobactam (>90% susceptibility). Ciprofloxacin, cefepime and ceftazidime show an activity level of around 85%; aminoglycosides, other β-lactams, chloramphenicol, linezoid and glycopeptides are not usually effective.1,3

Although it is an uncommon germ, it must be considered as an uncommon cause of bacteraemia, especially in patients with invasive medical devices, immunocompromised patients (including diabetics) and patients with previous broad-spectrum antibiotic treatment.4,5 Since it is a Beta-lactamase producer and presents multiple resistances to very strong antibiotics, empirical antibiotic therapy may not cover this bacillus. More epidemiological studies are required to explain the transmission mechanism and develop effective preventive measures.1,2

Conflicts of interest

The authors declare that they have no conflicts of interest related to the contents of this article.