Successful treatment of pulmonary melioidosis in an Australian dog.

Abstract

A 4-year-old female spayed Siberian Husky developed dyspnoea and lethargy during a flood event affecting southeast Queensland in 2022. Initial assessments revealed pyrexia, reduced respiratory function markers, neutrophilia, thrombocytopaenia and consolidation of the left caudal lung lobes. Despite several days of supportive care and broad-spectrum antimicrobials, the dog remained pyrexic, then deteriorated on day 5, developing left-sided pneumothorax. Computed tomography (CT) confirmed left caudal lung lobe consolidation with multiple gas foci, partial left cranial lung lobe consolidation and severe left-sided pneumothorax. The pneumothorax recurred despite repeated intermittent drainage via indwelling chest drains, prompting lobectomy of the left caudal lung lobe on day 5. The dog's fever and respiratory function improved within 24-h postoperatively. On day 8, histopathology returned with necrotising broncho-interstitial pleuropneumonia, and culture yielded Burkholderia pseudomallei. Antimicrobial therapy included amoxicillin clavulanic-acid (AMC) (day 1-21, then day 28-84), trimethoprim sulfadiazine (day 8-28), enrofloxacin (day 2-16) and doxycycline (day 8-16). After initial clinical resolution of all presenting complaints, pyrexia and painful pitting oedema of the left antebrachium developed on day 28. Comprehensive investigations did not confirm relapse of melioidosis. After reinstitution of AMC therapy, clinical signs and antebrachial swelling resolved. AMC was discontinued on day 84. There was no evidence of recurrence during the follow-up period, and the dog died of unrelated causes 785 days after the original presentation. This case is the first description of successful treatment of canine pulmonary melioidosis in a region not previously associated with high endemicity.