Bacteraemia by Achromobacter denitrificans in Hemodialysis

Sir,

Achromobacter denitrificans is a ubiquitous gram-negative bacterium.[1] Metabolically, it is a strictly aerobic, non-fermenting, mobile, catalase-positive and oxidase-positive bacterium.[2] A. denitrificans inhabit soils and aquatic environments, including well water, intravenous fluids and water in humidifiers, occasionally being part of the normal flora of some parts of the body and rarely a causal agent of human infections.[12] Here, we present the first case of central venous catheter-related bacteraemia on hemodialysis due to A. denitrificans.

A 29-year-old male, hypertensive and with chronic kidney disease of 11 years of duration. After a hemodialysis (HD) session with a single central venous catheter, he developed fever for 3 weeks followed by HD catheter-associated bacteraemia. On physical examination, the presence of a systolic mitral murmur g II/VI stands out. His laboratory results were: Haemoglobin 12 g/dL, blood urea 124 mg/dL, serum creatinine 17.2 mg/dL, leukocytosis (10,200 cells/μL) with neutrophilia (74%), glucose 87 mg/dL, viral panel was non-reactive for Human Immunodeficiency Virus, Hepatitis B and C; liver function tests and serum electrolytes were normal. Central and peripheral blood culture reported Achromobacter denitrificans isolation through the BioMérieux VITEK-2® system; the sensitivity profile based on the minimum inhibitory concentration was: Cefuroxime 8 g/mL, cefotaxime <1 g/mL, ceftazidime <1 g/mL, ceftriaxone <1 g/mL, cefepime <1 g/mL, meropenem 0.0.25 g/mL, amikacin <2 g/mL, gentamicin <1 g/mL, ciprofloxacin 0.0.25 g/mL, norfloxacin-0.5 g/mL and trimethoprim with sulfamethoxazole <20 g/mL; resistant to cephalotin and phosphomycin.

The transthoracic echocardiogram reported a vegetation of 5 × 2 mm in the tricuspid valve and the catheter tip in the right atrium presented a second vegetation of 7 × 5 mm, but the transoesophageal echocardiogram did not show any evidence of vegetations or thrombi. Left ventricular ejection fraction was 70%, left ventricular diastolic dysfunction, moderate mitral insufficiency and slight tricuspid were reported. Our patient did not have the classic risk factors for catheter-related bacteremia, that is, he was not diabetic or geriatric and his albumin was normal, so the main risk factor for infection in this case was the presence of a central venous catheter for HD.

Previous reports have identified A. denitrificans in peritonitis[3] or in peritoneal dialysis catheter exit site infection,[4] but there are no reports linking it to catheter infection. We consider that the catheter was contaminated by the antiseptic used and/or some mishandling by the staff, since being an isolated case, with no outbreak in the unit, contamination of the dialysis fluid and multi-dose bottle heparin would be ruled out as sources. The HD catheter-associated bacteremia in our patient was successfully resolved using a fluoroquinolone-based antibiotic regimen for 14 days, with good clinical response and no catheter removal. In addition, there was no recurrence of symptoms after 4 sessions of HD.

To our knowledge, this is the only report describing A. denitrificans HD catheter-associated bacteraemia. A. denitrificans infections are rare, but increasingly frequent in dialysis patients, emerging as an opportunistic germ, so preventive measures should be reinforced.