Evaluation of post-mortem heart blood culture in a Chinese population

Background Post-mortem blood cultures have been used in a wide variety of research studies. However, their significance is still a matter of dispute among medico-legal experts. This study was aimed to determine the factors which influenced post-mortem blood culture results and to assess their value in determining the cause of death. Methods We retrospectively investigated 76 post-mortem cases with suspected infection and correlated pathological findings with heart blood culture results. Results We found that survival time after onset of illness was significantly associated with positive heart blood cultures (P=0.014). Blood culture results were not influenced by age, gender, prior antibiotic therapy, interval time from death to store or interval time from death to autopsy (P>0.05). In those who had heart blood cultures taken, 49 cases (64.5%) including four cases with mixed growth, showed positive results, and approximately one-third of blood cultures were sterile. The positive predictive value (PPV) was 77.6% (38/49) including two cases with mixed growth; most were genuine pathogens according to the clinical and pathological findings. However, the negative predictive value (NPV) was 59.3% (16/27). Escherichia coli, Streptococcus spp., Staphylococcus aureus, Streptococcus pneumoniae and Klebsiella spp. were isolated most often. Conclusion These findings suggest that the results of post-mortem heart blood cultures, when combined with clinical and pathological findings, strengthen the understanding of the cause of death.