Title : A rare polymicrobial bloodstream infection in end-stage renal disease: Enterobacter cloacae, and dual achromobacter species in a hemodialysis patient
Abstract:
Bloodstream infections are a major source of morbidity and mortality among patients with end-stage renal disease (ESRD) on hemodialysis, particularly when caused by uncommon and multidrug-resistant organisms. Achromobacter xylosoxidans and Achromobacter denitrificans are rare environmental pathogens that have emerged as opportunistic threats in immunocompromised hosts. However, co-infection with both species has not been previously documented in the hemodialysis population. We present a unique case of recurrent polymicrobial bacteremia involving Enterobacter cloacae, A. xylosoxidans, and A. denitrificans in a hemodialysis patient, highlighting critical challenges in diagnosis, management, and antimicrobial treatment.
A 51-year-old male with diabetes, hypertension, and end-stage renal disease presented to the emergency room with fever and chills that occurred during dialysis via a right chest tunneled dialysis catheter (TDC). Two months prior, a left forearm arteriovenous graft had been placed. Initial blood cultures at his dialysis center grew gram-negative bacilli, prompting treatment with vancomycin and gentamicin and transfer to the emergency room. A chest x-ray suggested pneumonia, hence antibiotics were changed to vancomycin and piperacillin-tazobactam. Due to concerns for TDC infection, a catheter change was recommended after several negative cultures. Enterobacter cloacae complex was later isolated, prompting a switch to meropenem. Following TDC removal and placement of a right femoral non-tunneled central venous catheter (CVC), subsequent cultures identified Achromobacter xylosoxidans sensitive to meropenem. After negative cultures, he was discharged home three weeks later. One month after discharge, he developed a fever and shortness of breath during dialysis. Vancomycin and gentamicin were started, and he was transferred to the emergency room. He was admitted to the intensive care unit for worsening hypoxemia and placed on bilevel positive airway pressure (BiPAP) ventilation. Oral vancomycin was initiated for Clostridium difficile colitis, following a positive glutamate dehydrogenase (GDH) antigen test and detection of toxin B. Blood cultures grew A. xylosoxidans, leading to meropenem treatment. The left internal jugular (IJ) TDC was removed. He experienced spontaneous bleeding at the graft site. A contrast tomography angiogram showed no pseudoaneurysm. An urgent graft excision revealed A. xylosoxidans in the resected arteriovenous graft, along with A. denitrificans in blood cultures. He developed transaminitis (likely due to meropenem use), leading to a switch to ceftazidime. After subsequent negative cultures, a left chest TDC was placed, and he was discharged.
This case underscores the clinical significance of environmental pathogens in healthcare-associated infections and the need for vigilance in immunocompromised populations. Polymicrobial bloodstream infections, particularly with rare and resistant organisms, pose diagnostic, therapeutic, and infection control challenges. Early source control, organism-directed therapy, and careful monitoring for antimicrobial toxicity are critical for favorable outcomes.
Presenting cases like this enhances clinician awareness of emerging pathogens, informs future approaches to vascular access management, and supports the urgent need for antimicrobial stewardship strategies in high-risk patients. Further case series and studies are warranted to guide best practices in managing polymicrobial infections in hemodialysis populations.
