Ochrobactrum anthropi Bacteremia in a Patient on Hemodialysis: Challenges in Diagnosis and Management

Résumé fourni par la source

Introduction: Staphylococcus species are the most common cause of catheter-related bloodstream infections (CRBSIs) in dialysis patients. Gram-negative organisms like E. coli, Klebsiella, and Pseudomonas can also cause CRBSIs, often from the GI/GU tract or contaminated equipment. Ochrobactrum anthropi is a low-virulence, non-lactose-fermenting gram-negative bacillus found in soil and water. It is an emerging pathogen in immunocompromised patients and those with indwelling catheters. We report a rare case of O. anthropi CRBSI in a dialysis patient. Case Description: 79-year-old woman with ESRD on dialysis via tunneled CVC and bioprosthetic aortic valve replacement presented with tachypnea during dialysis. She was afebrile and saturating well. Chest X-ray, ECG, and respiratory panel were unremarkable; labs showed mild leukocytosis. She was admitted and underwent dialysis the next day, after which she developed chills, rigors, tachycardia, and tachypnea. Blood cultures were drawn, and vancomycin was given. Cultures grew gram-negative rods, and empiric piperacillin-tazobactam was started. Despite treatment, multiple cultures from the CVC and periphery, drawn 48 hours apart, remained positive. She was asymptomatic between sessions, but symptoms recurred post-dialysis. Echocardiogram showed possible catheter tip vegetation, prompting CVC removal. PCR initially failed to identify the organism, confirmed as O. anthropi a week later. Based on sensitivities, antibiotics were escalated to meropenem. After four catheter-free days and negative cultures, a new tunneled catheter was placed. She was discharged on ciprofloxacin and gentamicin. Discussion: In hemodialysis patients, O. anthropi infections may stem from contaminated equipment, fluids, water systems, or aseptic breaches. Its rarity can delay diagnosis, and automated biochemical systems may misidentify it due to similarity with other gram-negative rods. Advanced methods like 16S rRNA sequencing and MALDI-TOF MS improve accuracy. Infective endocarditis is a rare complication of persistent O. anthropi bacteremia, linked to biofilm formation, making CVC removal essential. Management is complicated by unpredictable resistance, limiting empiric therapy. CRBSI caused by O. anthropi is rare, and pitfalls may arise due to its ability to form biofilms, unique resistance patterns, and potential for misidentification and delay in diagnosis.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.