Lung Abscess Caused by Chromobacterium violaceum: An Unusual Presentation

Background: Chromobacterium violaceum is a Gram-negative coccobacilli that usually produces the pigment violacein; however, infections caused by non-pigmented strains are rarely reported.Case description: A 32-year-old male taxi driver presented with fever and hemoptysis for 3 weeks.He developed respiratory failure requiring oxygen support and was newly diagnosed with type II diabetes mellitus.Empirical antibiotics were started for suspected community-acquired pneumonia.High-resolution computed tomography of the thorax revealed bilateral multilobar cavities with air-fluid levels.Diagnostic aspiration yielded frank pus, which was sterile on culture.Pus, sputum, and blood cultures were all negative.A bronchoalveolar lavage (BAL) was also sterile, with CBNAAT negative for Mycobacterium tuberculosis.Serum procalcitonin was elevated, indicating septic shock.Despite treatment with Piperacillin-tazobactam, the patient had persistent fever spikes, leading to an escalation to Meropenem.A chest X-ray showed a right lower zone cavity with an air-fluid level.Ultrasound of the thorax showed bilateral "C-profiles" with increased echoes.Frank pus was aspirated and sent for culture.Suspecting abscess rupture with pyopneumothorax, pigtail catheterization was performed.Repeat culture using the VITEK system identified C. violaceum.The patient was treated with sensitive antibiotics for 21 days, after which his respiratory failure resolved.Discussion: Chromobacterium violaceum is associated with soft tissue infections, but necrotizing pneumonia leading to sepsis is rare.Uncontrolled diabetes mellitus in this patient likely contributed to an immunocompromised state.The non-pigmented strain required automated cultures for identification.Conclusion: This case emphasizes considering C. violaceum in immunocompromised patients with lung abscesses and highlights the need for prompt treatment.Clinical significance: A high degree of clinical suspicion, followed by sampling with advanced techniques, is required for the diagnosis of this notorious organism, C. violaceum.