Unresolving pneumonia in type 2 diabetes, think fungus: A case report of polymicrobial lung disease

Polymicrobial pneumonia caused by multiple pathogens is increasingly recognized in immune compromised individuals with comorbidities such as type 2 diabetes mellitus (T2DM). The immunocompromised state associated with T2DM predisposes patients to polymicrobial opportunistic infections, including multidrug-resistant bacteria and fungi. Prompt laboratory 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 three-month history of left-sided chest pain, dry cough, dyspnoea, and persistent fever. Initial empirical antibiotic therapy with intravenous ceftriaxone was ineffective. Computed tomography (CT) with contrast imaging revealed a massive loculated left pleural effusion with compressive atelectasis. Analysis of microbiological culture and sensitivity results revealed a polymicrobial infection involving multidrug-resistant Klebsiella pneumoniae, Enterobacter spp with inducible AmpC resistance, and fluconazole-susceptible dose dependent Candida glabrata. Based on the laboratory results, intravenous meropenem, high dose antifungal therapy, and subsequent oral fluconazole were recommended and led to successful treatment. Glycaemic control was concurrently optimized with insulin therapy and initial random blood sugar levels were 16.7 mmole per l, and at discharge was 9.3 mmoles per l.

This case emphasizes the importance of considering polymicrobial infections in diabetic patients presenting with unresolving pneumonia. Early use of imaging and microbiological analysis of the pleural fluid enabled prompt identification of the polymicrobial causative organisms, guiding tailored antimicrobial therapy. Multidisciplinary management is essential in improving outcomes in such complex cases.