Unresolving Pneumonia in Type 2 Diabetes: Case Report of Polymicrobial Lung Disease.

Polymicrobial pneumonia caused by the simultaneous infection with multiple pathogens is increasingly recognized in individuals with comorbidities such as type 2 diabetes mellitus (T2DM). The immunocompromised state associated with T2DM predisposes patients to both typical and opportunistic infections, including multidrug-resistant bacteria and fungi. Prompt diagnosis and organism-specific treatment are critical for optimal outcomes. We report the case of a 53-year-old male with newly diagnosed T2DM who presented with a 3-month history of left-sided chest pain, dry cough, dyspnoea, and persistent fever. Initial empirical antibiotic therapy was ineffective. Imaging revealed a massive loculated left pleural effusion with compressive atelectasis. Pleural fluid analysis identified a polymicrobial infection involving multidrug-resistant Klebsiella pneumoniae, Enterobacter spp. with inducible AmpC resistance, and azole-resistant Candida glabrata. Intravenous meropenem, echinocandin antifungal therapy, and subsequent oral fluconazole were recommended for successful treatment. Glycaemic control was concurrently optimized with insulin therapy. This case emphasizes the importance of considering polymicrobial infections in diabetic patients presenting with unresolving pneumonia. Early use of imaging and pleural fluid analysis enabled prompt identification of the causative organisms, guiding tailored antimicrobial therapy. Multidisciplinary management is essential in improving outcomes in such complex cases.