Isolation of Delftia acidovorans in Respiratory Samples: Highlighting the Importance of Critical Interpretation and Quality Control in Clinical Microbiology

Abstract

Delftia acidovorans is an environmental non-fermenting Gram-negative bacillus rarely associated with human infection. Its isolation from clinical specimens may generate diagnostic and therapeutic challenges. We report two hospitalized patients from a tertiary-care hospital in Neuquén Province, Argentina, in whom D. acidovorans was isolated from respiratory samples within a short period. Due to local laboratory limitations, isolates were referred for identification by MALDI-TOF mass spectrometry. Repeated recovery of this uncommon organism, together with poor clinicomicrobiological correlation, prompted an epidemiological investigation because of suspected pseudo-outbreak. An active search for contamination sources related to specimen collection and processing was performed. D. acidovorans was subsequently isolated from the N-acetylcysteine solution used as a mucolytic agent in the microbiology laboratory, confirming contamination during sample processing. This report underscores the importance of critical interpretation of microbiological findings, clinicomicrobiological correlation, and multidisciplinary collaboration to identify pseudo-outbreaks and prevent unnecessary antimicrobial treatment.