Nosocomial bronchopneumonia is a severe lung infection that develops more than 48 h after hospital admission and is frequently caused by antibiotic-resistant bacteria. It is often identified postmortem in forensic practice, particularly in patients with severe traumatic injuries requiring prolonged hospitalization and immobilization. Diagnosis is typically based on macroscopic findings and histopathological examination of lung tissue. This study aimed to evaluate the diagnostic value of postmortem microbiological testing by comparison with antemortem microbiological data. Ten patients with a clinical diagnosis of nosocomial bronchopneumonia were selected from forensic cases. During autopsy, tracheal swabs and lung tissue samples were collected and subjected to culture-based and molecular analyses. The results were compared with those obtained from antemortem microbiological investigations. Pathogens characteristic of nosocomial infections were identified; however, concordance with in-hospital microbiological data was highest when using next-generation sequencing (NGS) metagenomic analysis. Tracheal swab culture appears to have limited reliability for postmortem identification of bacterial agents in healthcare-associated bronchopneumonia. In contrast, metagenomic next-generation sequencing (mNGS) of lung tissue obtained at autopsy showed the highest concordance with antemortem microbiological findings and may provide valuable complementary diagnostic information, particularly in polymicrobial infections.

Healthcare-associated infections (HAIs) represent a major challenge in trauma patients, particularly in those requiring prolonged hospitalization, invasive procedures, surgery, or intensive care management. In forensic practice, these infections raise complex diagnostic and causal questions, especially when death occurs in patients with traumatic injuries, pre-existing chronic diseases, and post-traumatic complications. This chapter examines HAIs in trauma patients from a forensic and medico-legal perspective, with particular emphasis on traumatic brain injury, nosocomial bronchopneumonia, sepsis, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated pulmonary pathology. By integrating clinical data, imaging findings, microbiological results, autopsy observations, and histopathological examination, the chapter highlights the importance of postmortem investigation in clarifying the cause of death and the role of infection in the thanatogenic chain. Attention is given to the distinction between direct traumatic death, indirect death mediated by infectious complications, and multifactorial death involving trauma, infection, and chronic disease. The chapter also discusses the medico-legal implications of underdiagnosed HAIs and emphasizes the role of forensic autopsy in identifying overlooked complications, reconstructing causal relationships, and supporting objective expert conclusions.