Bacteria as Normal Flora in Postmortem Body Fluid Samples

Abstract

Bacterial culture and identification are both useful in the clinical and forensic fields, although the postmortem changes in human microbiology are poorly understood. This study aimed to identify bacteria that were considered normal flora in postmortem body fluid samples. Bacterial culture and identification testing were performed for 336 body fluid samples (e.g., cardiac blood, peripheral blood, pericardial fluid, pleural fluid, peritoneal fluid, cerebrospinal fluid, and urine) from 129 forensic autopsy cases. Bacteria were identified using both genetic and biochemical methods, and testing for C-reactive protein (CRP) was used to identify the presence of antemortem inflammation. Among the 129 autopsy cases, 79 cases (69.3%) were negative for CRP, and bacterial culture and identification testing were performed for 185 samples from those 79 cases. Bacteria that were considered both normal flora and pathogens were identified in the CRP-negative cases. Therefore, the results from postmortem bacterial culture and identification testing should be interpreted in the context of other postmortem examination, including CRP testing. Furthermore, case selection, postmortem testing, and interpretations of the results should be performed by both clinical bacteriologists and forensic pathologists. To best of our knowledge, this is the first study to examine normal flora in various postmortem body fluid samples form Korean autopsy cases.