Mycobacterium abscessus pneumonia in an Atlantic bottlenose dolphin (Tursiops truncatus)

Mycobacterium abscessus pneumonia was diagnosed antemortem in a 23-yr-old male Atlantic bottlenose dolphin (Tursiops truncatus). Clinical signs included lethargy, hyporexia, coughing, and bloody respiratory discharge. Diagnostic findings included neutrophilic leukocytosis, anemia, elevated erythrocyte sedimentation rate, and repeated forceful exhaled breath (sputum) cytology, with acute inflammatory cells and acid-fast positive beaded rods. The bacteria were initially identified free in the sputum sample and subsequently were seen within neutrophils. A culture was positive for a rapidly growing, white, colony-forming organism confirmed as M. abscessus by polymerase chain reaction and DNA sequencing. Clinical signs initially resolved with multidrug therapy. Concurrent Pseudomonas aeruginosa infection complicated clinical management and contributed to terminal decline. The dolphin was euthanized 5 mo after initial diagnosis. Necropsy results demonstrated acid-fast positive bacteria in lung tissue and supported the diagnosis of M. abscessus pneumonia. Acid-fast stains and mycobacteria cultures should be considered when evaluating ill dolphins.