Severe pneumonia due to viral and multidrug-resistant bacterial coinfection in a critically ill patient: A case report

Abstract

 Introduction: Antimicrobial resistance and viral-bacterial coinfections in the intensive care unit (ICU) represent a growing challenge that increases morbidity and mortality, especially in patients with severe respiratory compromise due to COVID-19. The coexistence of multidrug-resistant bacterial pathogens and respiratory viruses is associated with greater clinical severity, diagnostic difficulty, and therapeutic limitations. Case presentation: A 42-year-old male with obesity was admitted for acute respiratory failure secondary to SARS-CoV-2 and required invasive mechanical ventilation. Given the lack of response to empirical treatment and negative conventional cultures, a molecular panel (FilmArray®) was performed which detected coinfection by Respiratory Syncytial Virus (RSV) and superinfection by Pseudomonas aeruginosa (10⁶ copies/mL) and Staphylococcus aureus (>10⁷ copies/mL). Multiple resistance determinants were identified: CTX-M, IMP and VIM genes in P. aeruginosa, along with mecA/C and the MREJ complex in S. aureus. Despite rescue treatment with colistin and vancomycin, the patient progressed to septic shock and died on the ninth day. Discussion: The synergistic interaction between multiple viruses and multidrug-resistant (MDR) bacteria enhances epithelial damage and drastically reduces therapeutic options. The presence of metallo-beta-lactamases (IMP, VIM) invalidates the use of carbapenems, leaving the clinician facing a scenario of extreme genomic resistance. Conclusion: This case underscores the complexity of multiple coinfections and the importance of molecular diagnostic tools for the timely identification of pathogens and resistance genes in the face of negative results from traditional cultures.