Bacteriological autopsy. I. A methodological study

Bacterial Translocation and Sample Contamination in Postmortem Microbiological Analyses

The diagnostic value of postmortem bacteriology has been discussed controversially for decades. In the study herein, contamination during sampling procedures and postmortem translocation were investigated to interpret postmortem microbiology results. One hundred medicolegal autopsy cases in total were included. Radiology, histology, bacteriology, and biochemistry were performed in all cases. Based on all investigation findings, 4 groups of cases were identified: death unrelated to infection, true infections, false positive (contamination during sampling procedures, postmortem translocation and mixed situations), and undetermined. The results of this study indicate that postmortem bacteriology provides useful data supporting infection-related deaths, especially when potentially significant observations are accompanied by consistent autopsy, histology, and biochemistry. Result interpretation requires careful evaluation of number and type of isolated microorganisms.

Postmortem angiography using femoral cannulation and postmortem microbiology

Despite the undeniable advantages of postmortem angiography, numerous questions have arisen concerning the influence that the injected contrast media may exercise on biological fluids and tissues collected for toxicological and biochemical investigations. Moreover, cardiac blood for microbiological investigations cannot be obtained post-angiography. In this study, we examined whether the peripheral blood collected prior to postmortem angiography, using percutaneous access to femoral vessels after skin surface disinfection, could be suitable for microbiological investigations when postmortem angiography with femoral vessel cannulation is also performed. A total of 66 cases were included in the study and were divided into two subgroups (angiography and bacteriology group, 33 cases and control group, 33 cases). Autopsies, histology, toxicology, bacteriology, and biochemical investigations (procalcitonin, C-reactive protein, interleukin-6, and soluble triggering receptors expressed on myeloid cells type 1) were performed in all cases. No statistically significant differences between the two groups were noted, and identified category distribution (death unrelated to infection, true infection, false positive, and undetermined) was rather similar in both studied populations. These preliminary results suggest that postmortem angiography using a femoral approach does not constitute an impediment to the collection of peripheral blood for microbiology and vice versa. Moreover, the use of femoral blood for microbiology does not lead to an increased risk of doubtful results.

The value of postmortem microbiology cultures

Since the inception of evidence-based scientific concepts in medicine in the 19th century, the utility of postmortem microbiologic examinations has been a topic of controversy. For every study describing a lack of correlation between antemortem clinical and laboratory findings and postmortem culture results, there is equal evidence from other studies that indicates at least some limited utility in select cases. While the contributions of autopsies and postmortem microbiologic examinations in the discovery of novel infectious microorganisms are generally appreciated by the medical and scientific societies, the problems of implementing routine procedures in daily autopsy practice clearly relate to the lack of consensus on their broader utility as well as to a lack of regulatory guidelines. This review provides an overview of the literature-based evidence regarding the utility of postmortem microbiologic examinations together with some practical aspects and guidelines for those confronted with the issue of whether to allow or discourage the use of bacteriologic cultures obtained during autopsies.

The autopsy: complete or not complete?

Less invasive or non-invasive alternatives to the complete autopsy have been sought for some time, and a range of methods, ranging from needle sampling to endoscopy to magnetic resonance imaging, have been considered. Evaluations of these methods are few and far between, but generally confirm the predictable conclusion that incomplete autopsies provide incomplete information. It is not difficult to envisage a situation whereby pressure for non-invasive autopsies will allow them to become prevalent, whether properly evaluated or not. However, used appropriately, non-invasive or less invasive autopsies may be valuable tools capable of answering specific questions in situations where it is not possible to perform a complete autopsy.

Bacteriological autopsy. II. Comparison of a group of cancer patients with a control group

A study of the results of bacteriological autopsy in a group of cancer patients compared with a control group was carried out. Autopsy was performed on 42 bodies within 24 hours of death. Thirty-two patients had died with a cancer and the remaining ten had died of cardiovascular disease. Tissue for microscopy and material and culture were taken from the same sites. The results of the inoculations were semiquantified, resulting in a culture score, and the results of the microscopy were classified according to presence of bacteria and kind of inflammation. Furthermore, grading was done according to the degree of inflammation and whether bacteria were seen at microscopy. The culture scores were significantly higher in the cancer group than in the control group. We found a significant correlation between score and presence of acute inflammation. Likewise, a significant correlation was found between score and presence of bacteria at microscopy. As a difference between the cancer group and the control group was seen, further research on bacteriological autopsy seems worthwhile.