PURPOSE: Achromobacter xylosoxidans is a rare, highly resistant gram negative bacillus, resembling that of Pseudomonas aeruginosa. It is most often described in patients with cystic fibrosis, malignancy, and nosocomial outbreaks. Very little is known about this organism in patients with interstitial lung disease (ILD).
METHODS: We describe a case of a 70-year-old female with a history of rheumatoid arthritis and associated interstitial lung disease who was admitted for hypoxic respiratory failure requiring mechanical ventilation.
RESULTS: On admission, the patient had an elevated white blood cell count and a chest x-ray revealing a bilateral reticular and alveolar filling pattern. On day 4, her sputum culture was positive for A. xylosoxidans subspecies denitrificans. No other source of infection was found. The organism was resistant to all flouroquiniolones, piperacillin/tazobactam, ceftriaxone, and gentamicin. It was sensitive to only ceftazidime, meropenem, imipenem, and, tetracycline. On meropenem, her respiratory status improved over the following two weeks and she was discharge to a ventilator weaning facility.
CONCLUSIONS: A. xylosoxidans is an important, highly resistant organism that can be found in patients with ILD. Though there is little known about this bacterium in ILD, studies from patients with cystic fibrosis have shown that it can be found as both a colonizer and in acute infection, often presenting challenges in treatment decisions. This case demonstrates the difficulty in determining the pathogenic implications of A. xylosoxidans when no other source of infection is found.
CLINICAL IMPLICATIONS: Until more studies emerge amongst patients with ILD, A. xylosoxidans is an organism that should be regarded and treated as a significant pathogen.
DISCLOSURE: The following authors have nothing to disclose: Zita Shiue, Thaddus Wilkerson, Burton Janis, Farah Madhani-Lovely
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