Unexpected Culprit: A Case Report of Pleuropulmonary Pantoea septica Infection in a Ketamine User.

Pantoea septica, a gram-negative bacillus typically associated with opportunistic bloodstream infections in neonatal intensive care units, rarely causes pulmonary infections in immunocompetent individuals. We present a case of a 30-year-old male with multifocal cavitary pneumonia, bilateral parapneumonic effusions, and positive blood cultures for Pantoea septica, occurring in the setting of prior ketamine abuse. The patient presented with fever, productive cough, chest pain, and worsening dyspnea, without significant medical history or immunocompromising conditions. Diagnostic evaluation revealed elevated inflammatory markers, characteristic radiographic findings, and successful treatment with intravenous antibiotics and pleural drainage. This case highlights the diagnostic challenge posed by Pantoea septica in pulmonary infections and suggests a potential link between ketamine abuse and susceptibility to uncommon pathogens, warranting further investigation into its immunomodulatory effects.