A review. Possible sources of ethanol ante- and post-mortem: its relationship to the biochemistry and microbiology of decomposition

"Not everything that can be counted counts" in ethanol toxicological results: an antemortem and postmortem technical interpretation focusing on driving under the influence

Ethanol blood analysis is the most common request in forensic toxicology, and some studies point to positive results in approximately one-third of all unnatural deaths. However, distinguishing sober deaths from drunk deaths is not as simple as it may seem. This technical, clinical, and forensic interpretation is proposed to interpret the ethanol toxicological results, discussing several artefacts and pitfalls that must be considered, namely focusing on driving under the influence. This work is presented with a practical and objective approach, aiming to alleviate the complexities associated with clinical, physiological, pathophysiological, and toxicological aspects to enhance comprehension, practicality, and applicability of its content, especially to courts. Particularly the physical integrity of the body, the postmortem interval, putrefactive signs, anatomic place of blood collection, alternative samples such as vitreous humour and urine, the possibility of postmortem redistribution, the inclusion of preservatives in containers, and optimal temperature conditions of shipment are among some of the aspects to pay attention. Although several biomarkers related to postmortem microbial ethanol production have been proposed, their translation into forensic routine is slow to be implemented due to the uncertainties of their application and analytical difficulties. Specifically, in the interpretation of ethanol toxicological results, "not everything that can be counted counts and not everything that counts can be counted" (attributed to Albert Einstein).

Blood alcohol concentration in the clinical laboratory: a narrative review of the preanalytical phase in diagnostic and forensic testing

The analysis of blood alcohol concentration (BAC), a pivotal toxicological test, concerns acute alcohol intoxication (AAI) and driving under the influence (DUI). As such, BAC presents an organizational challenge for clinical laboratories, with unique complexities due to the need for forensic defensibility as part of the diagnostic process. Unfortunately, a significant number of scientific investigations dealing with the subject present discrepancies that make it difficult to identify optimal practices in sample collection, transportation, handling, and preparation. This review provides a systematic analysis of the preanalytical phase of BAC that aims to identify and explain the chemical, physiological, and pharmacological mechanisms underlying controllable operational factors. Nevertheless, it seeks evidence for the necessity to separate preanalytical processes for diagnostic and forensic BAC testing. In this regard, the main finding of this review is that no literature evidence supports the necessity to differentiate preanalytical procedures for AAI and DUI, except for the traceability throughout the chain of custody. In fact, adhering to correct preanalytical procedures provided by official bodies such as European federation of clinical chemistry and laboratory medicine for routine phlebotomy ensures both diagnostic accuracy and forensic defensibility of BAC. This is shown to depend on the capability of modern pre-evacuated sterile collection tubes to control major factors influencing BAC, namely non-enzymatic oxidation and microbial contamination. While certain restrictions become obsolete with such devices, as the use of sodium fluoride (NaF) for specific preservation of forensic BAC, this review reinforces the recommendation to use non-alcoholic disinfectants as a means to achieve "error-proof" procedures in challenging operational environments like the emergency department.

A primary study of ethanol production in postmortem liver and muscle tissue of rats

OBJECTIVE

To study the characteristics of postmortem ethanol production and its relation with alcohol congeners in postmortem rat liver and muscle tissues.

METHOD

Postmortem liver and muscle tissues in Sprague-Dawley rats, from postmortem time interval (PMI) day 0-20, were analyzed via headspace gas chromatograph flame ionization detection to observe production of postmortem ethanol and 5 selected alcohol congeners.

RESULT

1. Putrid ethanol production increased gradually to a peak and then decreased with the prolongation of PMI; 2. Acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde were produced along with postmortem ethanol; 1-butanol was only detected from day 11-20; 3. The concentrations of acetaldehyde, 1-propanol and 3-methyl-butyraldehyde was related with ethanol production. Fifteen mathematical models were constructed for putrid ethanol production based on acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde.

CONCLUSION

A peak in postmortem ethanol production was identified. The production trends of acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde in the liver, and of 1-propanol in muscle, were consistent with those of ethanol, and could potentially to be used as biomarkers of postmortem ethanol production. Further human samples and data analysis are needed to verify this.

Preanalytical factors influencing the results of ethanol analysis in postmortem specimens

Excessive drinking and drunkenness are underlying factors in many fatal accidents, which make the quantitative determination of ethanol in postmortem (PM) specimens an essential part of all unnatural death investigations. The same analytical methods are used to determine ethanol in blood taken from living and deceased persons although the interpretation of the results is more complicated in medical examiner cases owing to various preanalytical factors. The biggest problem is that under anaerobic conditions ethanol can be produced naturally in decomposed bodies by microbial activity and fermentation of blood glucose. Ways are needed to differentiate antemortem ingestion of ethanol from PM synthesis. One approach involves the determination of ethanol in alternative specimens, such as bile, cerebrospinal fluid, vitreous humor and/or urine, and comparison of results with blood alcohol concentration (BAC). Another approach involves the analysis of various alcohol biomarkers, such as ethyl glucuronide, ethyl sulfate and/or phosphatidylethanol or the urinary metabolites of serotonin 5-hydroxytryptophol/5-hydroxyindoleacetic acid (5-HTOL/5-HIAA). If ethanol had been produced in the body by microbial activity, the blood samples should also contain other low-molecular volatiles, such as acetaldehyde, n-propanol and/or n-butanol. The inclusion of 1-2% w/v sodium or potassium fluoride, as an enzyme inhibitor, in all PM specimens is essential to diminish the risk of ethanol being generated after sampling, such as during shipment and storage prior to analysis. Furthermore, much might be gained if the analytical cut-off for reporting positive BAC was raised from 0.01 to 0.02 g% when PM blood is analyzed. During putrefaction low BACs are more often produced after death than high BACs. Therefore, when the cadaver is obviously decomposed, a pragmatic approach would be to subtract 0.05 g% from the mean analytical result. Any remaining BAC is expected to give a more reliable indication of whether alcohol had been consumed before death.

The role of microorganisms in the biotransformation of psychoactive substances and its forensic relevance: a critical interdisciplinary review

Microorganisms are widespread on the planet being able to adapt, persist, and grow in diverse environments, either rich in nutrient sources or under harsh conditions. The comprehension of the interaction between microorganisms and drugs is relevant for forensic toxicology and forensic chemistry, elucidating potential pathways of microbial metabolism and their implications. Considering the described scenario, this paper aims to provide a comprehensive and critical review of the state of the art of interactions amongst microorganisms and common drugs of abuse. Additionally, other drugs of forensic interest are briefly discussed. This paper outlines the importance of this area of investigation, covering the intersections between forensic microbiology, forensic chemistry, and forensic toxicology applied to drugs of abuse, and it also highlights research potentialities.

Key points

Microorganisms are widespread on the planet and grow in a myriad of environments.Microorganisms can often be found in matrices of forensic interest.Drugs can be metabolized or produced (e.g. ethanol) by microorganisms.

The Associations of Auto-Brewery Syndrome and Diabetes Mellitus: A Literature Review and Clinical Perspective

Endogenous production of alcohol without the external intake of alcohol is called auto-brewery syndrome (ABS), and to get its levels to rise to a level that it has physical symptoms of alcohol intake is rare. The most common cause of ABS is the metabolism of ingested carbohydrates by intestinal microflora. This occurrence does not happen in all normal individuals but only in some high-risk individuals. Patients with diabetes mellitus (DM) have been hypothesized to be at high risk for ABS. We searched databases, such as PubMed, Medline, and PubMed Central, to search for existing literature with relevant keywords. In the finalized review, we have included 30 relevant articles. Alcohol formed in the gut gets absorbed in the bloodstream and immediately gets metabolized, so usually it does not achieve a level in blood high enough to cause symptoms. In high-risk patients, there is an increase in the level of bloodstream alcohol above a certain level, so it shows symptoms. Because there is higher blood glucose in DM, the patients have been shown to be at increased risk for developing ABS. Similarly, obesity is also a risk factor for DM, making it a high-risk condition for ABS. The most involved pathogens are Candida and Saccharomyces.

Opioid related deaths in Norway in 2000-2019

AIMS

The aim of the study is to present autopsy-based findings of the most prevalent opioids in overdose deaths in Norway from 2000 to 2019, as such data are lacking in the current literature.

METHODS

Data on cause of death obtained from the Norwegian Cause of Death Registry (NCoDR) were linked with forensic toxicological results from forensic autopsies.

RESULTS

From year 2000 the annual numbers of overdose deaths decreased, specifically during 2000-2003, thereafter a relatively stable annual number was observed. Opioids were detected in 93% of the cases. Heroin related deaths have decreased, whereas medical opioids for pain treatment have increased with time. Men in their early 40's dominate the overall numbers of deaths, but significantly different sex patterns emerge when studying the specific drugs. During the past 20 years, the mean age at overdose death has increased by 10 years (from 33 to 43 years). Overdose deaths without any illicit drugs present at autopsy have increased in recent years. These deaths, where only potentially prescription medications were detected, were more common among women and with higher age.

CONCLUSIONS

In Norway during the past 20 years, we observe a dynamic shift in overdose deaths caused by heroin and illicit drugs, to include a gradually increasing trend of overdose deaths from pill based pain medications and also methadone and buprenorphine. This warrants a shift in preventive responses, as the target groups differ.

Modeling Postmortem Ethanol Production/Insights into the Origin of Higher Alcohols

The forensic toxicologist is challenged to provide scientific evidence to distinguish the source of ethanol (antemortem ingestion or microbial production) determined in the postmortem blood and to properly interpret the relevant blood alcohol concentration (BAC) results, in regard to ethanol levels at death and subsequent behavioral impairment of the person at the time of death. Higher alcohols (1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol (isoamyl-alcohol), and 3-methyl-2-butanol (amyl-alcohol)) are among the volatile compounds that are often detected in postmortem specimens and have been correlated with putrefaction and microbial activity. This brief review investigates the role of the higher alcohols as biomarkers of postmortem, microbial ethanol production, notably, regarding the modeling of postmortem ethanol production. Main conclusions of this contribution are, firstly, that the higher alcohols are qualitative and quantitative indicators of microbial ethanol production, and, secondly that the respective models of microbial ethanol production are tools offering additional data to interpret properly the origin of the ethanol concentrations measured in postmortem cases. More studies are needed to clarify current uncertainties about the origin of higher alcohols in postmortem specimens.

Development and Validation of an Analytical Method for Volatiles with Endogenous Production in Putrefaction and Submersion Situations

A group of 16 volatile substances (ethyl acetate, 2-propanol, 1-propanol, methanol, acetone, ethanol, acetaldehyde, diethyl ether, methyl ethyl ketone, 1-butanol, 2-butanol, t-butanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 1-pentanol) were qualitatively and quantitatively analyzed through a method developed for volatiles with endogenous production in putrefaction and submersion situations. The method was validated for blood, urine and vitreous humor, using a gas chromatograph (Varian 450-GC) with a flame ionization detector coupled to a headspace injector (HS-GC-FID). The vials were prepared by diluting 100 µL of the sample of interest in 1 mL of internal standard (acetonitrile 100 mg/L), using two capillary columns (VF-624ms and VF-5ms) with different polarities to ensure that all test compounds would be properly identified and undoubtedly distinguished from the rest. All volatiles were studied in a range of 50 to 2,000 mg/L in terms of selectivity/specificity, detection and quantification limits, linearity and calibration model, precision, accuracy, bias, robustness and stability according to the Scientific Working Group for Forensic Toxicology. Detection and quantification limits were between 1 to 8 mg/L and 4 to 24 mg/L, respectively, with coefficient of variation values under 10% in bias studies and in intermediate precision studies for most substances. The developed method was applied to real cases to test the method.

Modeling microbial ethanol production by S. aureus, K. pneumoniae, and E. faecalis under aerobic/anaerobic conditions - applicability to laboratory cultures and real postmortem cases

A quite intriguing subject being intensively researched in the forensic toxicology field is the source of postmortem determined blood ethanol concentration: antemortem ingestion or postmortem microbial production. Our previous research on microbial ethanol production has reported a quantitative relationship between the ethanol and the higher alcohols and 1-butanol produced by Escherichia coli, Clostridium perfrigens, and Clostridium sporogenes. In this contribution, we continue our research reporting on the following: (i) the patterns of ethanol, higher alcohols, and 1-butanol production by the microbes Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis (all being aerobic/facultative anaerobic species, common corpse's colonizers, and ethanol producers), under controlled laboratory conditions, (ii) the mathematical modeling, with simple mathematical equations, of the correlation between ethanol concentration and the other studied alcohols' concentrations, by performing multiple linear regression analysis of the results, and (iii) the applicability of the constructed models in microbial cultures developed under different temperature than that used to build the models, in denatured blood cultures and in real postmortem cases. The aforementioned alcohols were proved to be all indicators of ethanol production, both in qualitative and quantitative terms. 1-Propanol was the most significant alcohol in modeling microbial ethanol production, followed by methyl-butanol. The K. pneumoniae's models achieved the best scoring in applicability (E < 40%) compared to the S. aureus and E. faecalis models, both at laboratory microbial cultures at 37 °C and real postmortem cases. Overall, a noteworthy accuracy in estimating the microbial ethanol in cultures and autopsy blood is achieved by the employed simple linear models.

Modeling postmortem ethanol production by C. albicans: Experimental study and multivariate evaluation

In previous research, we modeled the ethanol production by certain bacteria under controlled experimental conditions in an attempt to quantify the production of microbial postmortem ethanol in cases where other alcohols were co-detected. This contribution on the modeling of postmortem ethanol production by Candida albicans is complementary to these previous studies. Τhis work aimed to study ethanol, higher alcohols (1-propanol, isobutanol, 2-methyl-1-butanol and 3-methyl-1-butanol), and 1-butanol production by Candida albicans: (i) in different culture media (Brain Heart Infusion, BHI and, Sabouraud Dextrose Broth, SDB), (ii) under mixed aerobic/anaerobic or strict anaerobic conditions, and (iii) at different temperatures (37 °C, 25 °C and, 4 °C), and develop simple mathematical models, resulted from fungal cultures at 25 °C, to predict the microbially produced ethanol in correlation with the other alcohols. The applicability of the models was tested in the C. albicans cultures in BHI and SDB media at 37 °C, in denatured human blood at 25 °C, acidic and neutral with different concentrations of additional glucose, in acidic denatured blood diluted with dextrose solution and in blood from autopsy cases. The received results indicated that the C. albicans models could apply in cases where yeasts have been activated in blood with elevated glucose levels. Overall, the in vitro ethanol production by C. albicans in blood depended on temperature, time, glucose (or carbohydrate) content, pH of the medium and endogenous changes in the medium composition through time. Our results showed that methyl-butanol is the most significant indicator of fungal ethanol production, followed by the equally important isobutanol and 1-propanol in qualitative and quantitative terms.

Inferences and Legal Considerations Following a Blood Collection Tube Recall

In mid-2019, medical, forensic and legal communities were notified that a certain shipment of evacuated blood sampling tubes were recalled by the manufacturer. This recall order described that the preservative sodium fluoride (100 mg) and anticoagulant potassium oxalate (20 mg) were missing from a small batch of 10-mL evacuated tubes. This gave cause for concern for possible implications in criminal justice (e.g., in drink-driving offenses) when blood-alcohol concentrations are interpreted. In reality, the lack of an anticoagulant would have been immediately obvious during sample preparation, owing to the formation of a large clot in the tube when received. Certain impairing drugs (e.g., cocaine and 6-acetylmorphine) are unstable in blood and tend to degrade without an enzyme inhibitor, such as sodium fluoride, present. In reviewing available literature related to current practices and the stability of ethanol in stored blood samples, there does not appear to be a clear consensus regarding the amount of sodium fluoride preservative necessary, if any at all, when blood is taken from living subjects under sterile conditions for typical forensic ethanol analysis.

Statistical comparisons of blood alcohol samples from 6-mL and 10-mL grey-top tubes

Historically, blood alcohol concentration (BAC) studies utilized a 1% concentration of the preservative sodium fluoride (NaF), leaving an information gap supporting usage of lower concentrations of NaF to preserve ethanol. As many forensic laboratories utilize Becton, Dickinson and Company 6-mL gray-top tubes (0.25% NaF), statistical comparisons were conducted to determine whether significant differences exist between BAC values obtained from 6-mL tubes versus 10-mL tubes (1% NaF). Whole blood was spiked at three concentrations, (0.04, 0.08, and 0.15 g/100 mL) and aliquoted into tubes at "low," "medium," and "high" fill volumes. Tubes were split into refrigerated or ambient storage and analyzed after 1, 3, 5, 7, and 30 days, using headspace gas chromatography. Each 6-mL and 10-mL tube pair, prepared, stored, and analyzed under identical conditions, was compared by t-test (95% confidence level). For refrigerated tubes, 32 of 45-tube pairs did not reject the null hypothesis (that 6-mL and 10-mL tubes yield equivalent BACs), and 31 of 45 ambient stored tube pairs did not reject the null hypothesis. Analysis of variance (ANOVA) found no significant differences between 6-mL and 10-mL gray-top tubes for 0.04 and 0.15 g/100 mL concentrations over 30 days; significant differences were observed for 0.08 g/100 mL concentration tubes, which warrants further study. Paired t-tests of grouped samples found no significant differences between 6-mL and 10-mL tubes at any concentration.

Microbial neoformation of volatiles: implications for the estimation of post-mortem interval in decomposed human remains in an indoor setting

The objective of this study was to determine if a relationship between microbial neoformation of volatiles and the post-mortem interval (PMI) exists, and if the volatiles could be used as a tool to improve the precision of PMI estimation in decomposed human remains found in an indoor setting. Chromatograms from alcohol analysis (femoral vein blood) of 412 cases were retrospectively assessed for the presence of ethanol, N-propanol, 1-butanol, and acetaldehyde. The most common finding was acetaldehyde (83% of the cases), followed by ethanol (37%), N-propanol (21%), and 1-butanol (4%). A direct link between the volatiles and the PMI or the degree of decomposition was not observed. However, the decomposition had progressed faster in cases with microbial neoformation than in cases without signs of neoformation. Microbial neoformation may therefore act as an indicator of the decomposition rate within the early decomposition to bloating stages. This may be used in PMI estimation based on the total body score (TBS) and accumulated degree days (ADD) model, to potentially improve the model's precision.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

Determination of serotonin metabolites in urine sample by liquid chromatography-mass spectrometry as biomarkers of recent alcohol intake: Implication for aircraft accident investigation

Background

Determination of ethanol levels in aircraft accident victims constitutes an important part of investigation. However, postmortem production of alcohol by microbial fermentation is known to interfere with the results. Distinguishing postmortem produced alcohols from antemortem ingested is very important in interpretation of results. Ratio of 5-hydroxytryptophol (5-HTOL) and 5-hydroxyindole-3-acetic acid (5-HIAA) metabolites of serotonin, has known to provide a convenient, rapid, and reliable solution as antemortem ethanol leads to an elevation in the 5-HTOL/5-HIAA ratio after ingestion of alcohol (5-HTOL/5-HIAA = >15 pm/nm).

Methods

Triple quadruple (QQQ) liquid chromatography-mass spectrometry (LC-MS) with electrospray ionization positive mode has been used for development of single tube multiple reaction monitoring (MRM) method for simultaneous quantification of 5-HTOL and 5-HIAA in urine. Deglucuronidation of 5-HTOL glucuronide in urine by beta-glucuronidase followed by simple sample preparation has been adopted. Examination of the ratio on urine samples from 15 individuals after consumption of 60 and 90 ml of whiskey has been carried out at different time interval.

Results

A single method for analysis of both the analytes was developed with sensitivity of 50 ppb and recovery of around 80-90%. Examination of the ratio on urine samples revealed that the ratio was >15 in all groups consuming 60 ml and 90-ml whiskey up to 12 h after alcohol ingestion.

Conclusion

This is a unique highly sensitive single LC-MS method, which has been developed for simultaneous estimation of both 5-HTOL and 5-HIAA on same instrument for proving antemortem alcohol ingestion with high degree of sensitivity and specificity.

High Correlation between Ethanol Concentrations in Postmortem Femoral Blood and in Alternative Biological Specimens, but Large Uncertainty When the Linear Regression Model Was Used for Prediction in Individual Cases

In connection with medicolegal autopsies peripheral blood (e.g. from a femoral vein) is the specimen of choice for toxicological analysis, although alternative specimens are also sometimes submitted, such as bile, cerebrospinal fluid (CSF), vitreous humor (VH), bladder urine, pleural effusions and/or lung fluid. Ethanol concentrations were determined in duplicate in femoral blood and in various alternative biological specimens by headspace gas chromatography. The analysis was carried out on two different fused silica capillary columns furnishing different retention times for ethanol and both n-propanol and t-butanol were used as internal standards. The results were evaluated by linear regression using blood alcohol concentration (BAC) as dependent or outcome variable and the concentrations in an alternative specimen as independent or predictor variable. The Pearson correlation coefficients were all statistically highly significant (P &lt; 0.001); r = 0.94 (bile), r = 0.98 (CSF), r = 0.97 (VH), r = 0.92 (urine), r = 0.94 (lung fluid) and r = 0.96 (pleural cavity effusions). When the regression model was used to predict femoral BAC from the mean concentration in an alternative specimen the mean and 95% prediction intervals were 1.12 ± 0.824 g/L (bile), 1.41 ± 0.546 g/L (CSF), 1.15 ± 0.42 g/L (VH), 1.29 ± 0.780 g/L (urine), 1.25 ± 0.772 g/L (lung fluid) and 0.68 ± 0.564 g/L (pleural cavity effusions). This large uncertainty for a single new observation needs to be considered when alcohol-related deaths are evaluated and interpreted. However, the analysis of alternative specimens is recommended in medical examiner cases to provide supporting evidence with regard to the origin of ethanol, whether this reflects antemortem (AM) ingestion or postmortem (PM) synthesis.

Epidemiology of alcohol-related unintentional drowning: is post-mortem ethanol production a real challenge?

BACKGROUND

Post-mortem (PM) ethanol production may hamper the interpretation of blood alcohol concentration (BAC) in victims of drowning. Different exclusion criteria (e.g. cases with low BAC or with protracted interval between death and toxicological analysis) have been proposed with no factual figures to reduce the potential bias due to PM ethanol production when examining the prevalence rates for alcohol-related drowning. The aim of this study is to verify the extent to which PM alcohol production may affect the accuracy of studies on drowning and alcohol.

FINDINGS

Unintentional fatal drowning cases (n = 967) for which a full medico-legal autopsy and toxicological analysis was performed, in Finland, from 2000 to 2013, and relevant variables (demographic data of the victims, month of incident, PM submersion time, blood alcohol concentration, urine alcohol concentration (UAC), vitreous humour alcohol concentration (VAC) were available. Overall, out of 967 unintentional drownings, 623 (64.4%) were positive for alcohol (BAC > 0 mg/dL), 595 (61.5%) had a BAC ≥ 50 mg/dL, and 567 (58.6%) a BAC ≥ 100 mg/dL. Simultaneous measurements, in each victim, of BAC, UAC, and VAC revealed PM ethanol production in only 4 victims (BAC: 25 mg/dL - 48 mg/dL). These false positive cases represented 0.4% of drownings with BAC > 0 mg/dL and 14.3% of drownings with BAC > 0 mg/dL and < 50 mg/dL.

CONCLUSIONS

The present study suggests that PM ethanol production has a limited impact on research addressing the prevalence rate for alcohol-related drowning and that the use of too rigorous exclusion criteria, such as those previously recommended, may led to a significant underestimation of actual alcohol-positive drowning cases.

Simple detection of bacterioplankton using a loop-mediated isothermal amplification (LAMP) assay: First practical approach to 72 cases of suspected drowning

We developed a novel molecular tool for assisting the diagnosis of death by drowning and evaluated its validity in forensic practical cases. Two novel sets of loop-mediated isothermal amplification (LAMP) primers were designed to detect either representative freshwater (Aeromonas) or marine (Vibrio, Photobacterium, Listonella) bacterioplankton (aquatic bacteria) in one tube using the LAMP technique. The assay involves only mixing template DNA with seven reagents and incubating at 64°C for 80min and does not require special or expensive equipment because detection is based on visual observation under natural light. The assay's excellent specificity was also demonstrated using 17 standard (control) strains and 124 other bacterial strains cultured from drowning and non-drowning victims in our previous studies. We then assayed 299 specimens (135 lung, 164 blood) from 72 victims, including 45 who had drowned in rivers, ditches, seas, and around estuaries. LAMP assay results could provide effective information to assist the diagnosis of death by drowning in practical cases. The LAMP assay would be useful for suspected drowning cases, as it is a less-laborious and less-expensive minimal test when death by drowning is sufficiently confirmed or negated from only autopsy findings and environmental data or when diatom testing is not performed due to logistic, personnel, or budgetary limitations. Moreover, the assay could serve as a simple additional test when the density of diatoms in the lungs is very low due to low density in the water.

[The development and validation of the method for the identification of ethyl glucuronide and ethyl sulfate as the markers of the consumption of ethyl alcohol during one's lifetime]

The objective of the present study was the development and validation of the rapid reproducible method for the identification of ethyl glucuronide and ethyl sulfate allowing to store and transport the study specimens without the loss of the substances of interest by placing the samples on the paper. We have developed the validated technique for the detection and quantitative determination of ethyl glucuronide and ethyl sulfate in the cadaveric blood and urine by means of low-resolution tandem mass-spectroscopy with the use of deuterated derivatives of these substances as the internal standards. The low threshold for quantitative determination of both above substances is 50 ng/ml for the blood and 100 ng/ml for the urine. The method is characterized by the accuracy and precision with the coefficient of variation below 15% and the influence of the matrix with the coefficient of variation below 15%. The evaluation of stability of the two analytes in blood when stored in the dry condition on the paper carrier during 2 weeks showed that the coefficient of variation did not exceed 6.4%. The comparative study of ethyl glucuronide and ethyl sulfate in the samples of cadaveric blood and urine containing from 0 to 5.2% of ethyl alcohol was carried out. The methods for the transportation of the biological fluids and for the extraction of ethyl glucuronide and ethyl sulfate placed on the paper carrier (Whatman 903) have been proposed. The possibility has been demonstrated to use ethyl glucuronide and ethyl sulfate as the markers of the consumption of ethyl alcohol during one's lifetime for the purpose of investigation of the putrifactive changes of the blood components.

Cadaver Thanatomicrobiome Signatures: The Ubiquitous Nature of Clostridium Species in Human Decomposition

Human thanatomicrobiome studies have established that an abundant number of putrefactive bacteria within internal organs of decaying bodies are obligate anaerobes, Clostridium spp. These microorganisms have been implicated as etiological agents in potentially life-threatening infections; notwithstanding, the scale and trajectory of these microbes after death have not been elucidated. We performed phylogenetic surveys of thanatomicrobiome signatures of cadavers' internal organs to compare the microbial diversity between the 16S rRNA gene V4 hypervariable region and V3-4 conjoined regions from livers and spleens of 45 cadavers undergoing forensic microbiological studies. Phylogenetic analyses of 16S rRNA gene sequences revealed that the V4 region had a significantly higher mean Chao1 richness within the total microbiome data. Permutational multivariate analysis of variance statistical tests, based on unweighted UniFrac distances, demonstrated that taxa compositions were significantly different between V4 and V3-4 hypervariable regions (p < 0.001). Of note, we present the first study, using the largest cohort of criminal cases to date, that two hypervariable regions show discriminatory power for human postmortem microbial diversity. In conclusion, here we propose the impact of hypervariable region selection for the 16S rRNA gene in differentiating thanatomicrobiomic profiles to provide empirical data to explain a unique concept, the Postmortem Clostridium Effect.

Best-practices approach to determination of blood alcohol concentration (BAC) at specific time points: Combination of ante-mortem alcohol pharmacokinetic modeling and post-mortem alcohol generation and transport considerations

Alcohol concentrations in biological matrices offer information regarding an individual's intoxication level at a given time. In forensic cases, the alcohol concentration in the blood (BAC) at the time of death is sometimes used interchangeably with the BAC measured post-mortem, without consideration for alcohol concentration changes in the body after death. However, post-mortem factors must be taken into account for accurate forensic determination of BAC prior to death to avoid incorrect conclusions. The main objective of this work was to describe best practices for relating ante-mortem and post-mortem alcohol concentrations, using a combination of modeling, empirical data and other qualitative considerations. The Widmark modeling approach is a best practices method for superimposing multiple alcohol doses ingested at various times with alcohol elimination rate adjustments based on individual body factors. We combined the selected ante-mortem model with a suggestion for an approach used to roughly estimate changes in BAC post-mortem, and then analyzed the available data on post-mortem alcohol production in human bodies and potential markers for alcohol production through decomposition and putrefaction. Hypothetical cases provide best practice approaches as an example for determining alcohol concentration in biological matrices ante-mortem, as well as potential issues encountered with quantitative post-mortem approaches. This study provides information for standardizing BAC determination in forensic toxicology, while minimizing real world case uncertainties.

Ethyl Glucuronide Positivity Rate in a Pain Management Population

Ethanol may be consumed by some patients as a means to manage their pain or psychiatric disorder. Consequently, there is the potential to consider ethanol a co-therapeutic in pain management. The purpose of this study was to perform a retrospective analysis to evaluate the rate of ethanol use in a population of patients in pain management programs that were evaluated by our in-house pain management drug panel test. Results from this retrospective study showed that 12.6% of patients in a pain management population were positive for the direct ethanol metabolite, ethyl glucuronide (EtG), by immunoassay. Furthermore, 86% of the individuals positive for EtG were also positive for prescription pain medication and illicit drugs. Results presented here suggest that ethanol use should be routinely monitored in pain management populations in an effort to determine any potential adverse effects of ethanol-drug interactions and as a way to further evaluate the effect of ethanol on pain management outcomes. Testing this population of patients suggests that ethanol use is prevalent and the risk of drug-ethanol adverse effects should be monitored in a pain management population.

Impact of cemeteries on groundwater contamination by bacteria and viruses - a review

In the process of decomposition of a human body, 0.4-0.6 litres of leachate is produced per 1 kg of body weight. The leachate contains pathogenic bacteria and viruses that may contaminate the groundwater and cause disease when it is used for drinking. So far, this topic has been investigated in several regions of the world (mainly Brazil, Australia, the Republic of South Africa, Portugal, the United Kingdom and Poland). However, recently more and more attention has been focused on this issue. This study reviews the results of investigations related to the impact of cemeteries on groundwater bacteriology and virology. This topic was mainly discussed in the context of the quantities and qualities of changes in types of microorganisms causing groundwater contamination. In some cases, these changes were related to the environmental setting of a place, where a cemetery was located. The review is completed by a list of recommendations. Their implementation aims to protect the local environment, employees of funeral homes and the residents living in the vicinity of cemeteries. In this form, this review aims to familiarize the reader with the results of this topic, and provide practical guidance for decision-makers in the context of expansion and management of cemeteries, as well as the location of new ones.

Promising blood-derived biomarkers for estimation of the postmortem interval

A linear correlation between blood putrefaction time and biochemical parameter concentrations was obtained. Two mathematical models that may have predictive value for estimation of thepostmorteminterval were developed. The obtained results might be complementary procedures for the methodologies already used.

Postmortem Ethanol Concentrations and Postmortem Ethanol Production

A review of the literature was conducted in reference to postmortem blood ethanol concentrations and the issue of postmortem production of ethanol. Ethanol in postmortem specimens may occur as a result of antemortem consumption (most common), postmortem production in the body or in vitro by microorganisms (less common), and endogenous production by microorganisms during life (rare). The portion of ethanol-positive postmortem cases in which postmortem production of ethanol is thought to have occurred is small, as is the portion of cases in which postmortem production of ethanol is a potentially important issue. It is unusual for postmortem production of ethanol to account for more than a 70 mg/dL concentration, but cases with higher concentrations occasionally occur. Cases in which blood ethanol is positive but vitreous ethanol concentration is much lower or negative, and/or in which the urine: blood ethanol concentration ratio is less than one are supportive of postmortem ethanol production. The presence of other alcohols such as n-propanol and/or n-butanol is suggestive of postmortem microbial production of ethanol. The ratio of serotonin metabolites in urine may be helpful in distinguishing postmortem production of ethanol from antemortem consumption, as may the concentration of ethyl glucuronide in blood. Candida and some other species may produce ethanol in urine antemortem and postmortem. In rare instances such as infections, endogenous ethanol production may occur in a living person. Recommendations are made concerning samples to collect and tests that may be helpful in distinguishing antemortem ethanol consumption from postmortem production of ethanol.

A microbial clock provides an accurate estimate of the postmortem interval in a mouse model system

Establishing the time since death is critical in every death investigation, yet existing techniques are susceptible to a range of errors and biases. For example, forensic entomology is widely used to assess the postmortem interval (PMI), but errors can range from days to months. Microbes may provide a novel method for estimating PMI that avoids many of these limitations. Here we show that postmortem microbial community changes are dramatic, measurable, and repeatable in a mouse model system, allowing PMI to be estimated within approximately 3 days over 48 days. Our results provide a detailed understanding of bacterial and microbial eukaryotic ecology within a decomposing corpse system and suggest that microbial community data can be developed into a forensic tool for estimating PMI.

DOI:http://dx.doi.org/10.7554/eLife.01104.001

Our bodies—especially our skin, our saliva, the lining of our mouth and our gastrointestinal tract—are home to a diverse collection of bacteria and other microorganisms called the microbiome. While the roles played by many of these microorganisms have yet to be identified, it is known that they contribute to the health and wellbeing of their host by metabolizing indigestible compounds, producing essential vitamins, and preventing the growth of harmful bacteria. They are important for nutrient and carbon cycling in the environment.

The advent of advanced sequencing techniques has made it feasible to study the composition of this microbial community, and to monitor how it changes over time or how it responds to events such as antibiotic treatment. Sequencing studies have been used to highlight the significant differences between microbial communities found in different parts of the body, and to follow the evolution of the gut microbiome from birth. Most of these studies have focused on live animals, so little is known about what happens to the microbiome after its host dies. In particular, it is not known if the changes that occur after death are similar for all individuals. Moreover, the decomposing animal supplies nutrients and carbon to the surrounding ecosystem, but its influence on the microbial community of its immediate environment is not well understood.

Now Metcalf et al. have used high-throughput sequencing to study the bacteria and other microorganisms (such as nematodes and fungi) in dead and decomposing mice, and also in the soil beneath them, over the course of 48 days. The changes were significant and also consistent across the corpses, with the microbial communities in the corpses influencing those in the soil, and vice versa. Metcalf et al. also showed that these measurements could be used to estimate the postmortem interval (the time since death) to within approximately 3 days, which suggests that the work could have applications in forensic science.

DOI:http://dx.doi.org/10.7554/eLife.01104.002

Microbial ethanol production in postmortem urine sample

We present a case in which postmortem blood ethanol concentration was 0.02 g/kg and acetone concentration was 0.51 g/kg, while urine ethanol concentration was 6.0 g/kg and acetone concentration was 0.63 g/kg. In the urine sample, sodium fluoride was not added. The urinary ethanol concentration continued to increase without any remarkable increase of isopropanol concentration and external contamination was excluded. Species of bacteria and yeasts, including Candida glabrata, were isolated from urine and blood samples. A few days after the collection of samples, we received the information that the patient was diabetic and did not receive insulin therapy regularly. To prevent postmortem microbial ethanol production and incorrect diagnosis of the cause of death, it is necessary to add sodium fluoride to blood and urine samples collected from diabetic patients.

Modeling microbial ethanol production by E. coli under aerobic/anaerobic conditions: applicability to real postmortem cases and to postmortem blood derived microbial cultures

The mathematical modeling of the microbial ethanol production under strict anaerobic experimental conditions for some bacterial species has been proposed by our research group as the first approximation to the quantification of the microbial ethanol production in cases where other alcohols were produced simultaneously with ethanol. The present study aims to: (i) study the microbial ethanol production by Escherichia coli under controlled aerobic/anaerobic conditions; (ii) model the correlation between the microbial produced ethanol and the other higher alcohols; and (iii) test their applicability in: (a) real postmortem cases that had positive BACs (>0.10 g/L) and co-detection of higher alcohols and 1-butanol during the original ethanol analysis and (b) postmortem blood derived microbial cultures under aerobic/anaerobic controlled experimental conditions. The statistical evaluation of the results revealed that the formulated models were presumably correlated to 1-propanol and 1-butanol which were recognized as the most significant descriptors of the modeling process. The significance of 1-propanol and 1-butanol as descriptors was so powerful that they could be used as the only independent variables to create a simple and satisfactory model. The current models showed a potential for application to estimate microbial ethanol - within an acceptable standard error - in various tested cases where ethanol and other alcohols have been produced from different microbes.

Demonstration of ethyl glucuronide in dental tissue samples by liquid chromatography/electro-spray tandem mass spectrometry

INTRODUCTION

Ethyl glucuronide (EtG) has been studied in various tissues and body fluid for determination of alcohol intake. However, no study, dealing with EtG analysis in dental tissue, was performed so far. In this study, we aimed to demonstrate EtG levels in dental tissue.

MATERIALS AND METHODS

Michigan Alcohol Screening Test (MAST) was performed to 29 participants. Following the test, cases were divided into three groups as non-hazardous alcohol users, alcohol abusers and 6 controls who verbally declared that they were abstainers. A total of 29 tooth specimens, obtained from participants, was included in the study. These specimens were analyzed using LC/MS/MS.

RESULTS

All of the participants included in the study were male. According to the MAST outcomes 14 of the participants were non-hazardous alcohol users, and 9 were alcohol abusers, while 6 patients verbally declared that they were abstainers. Dental tissue analyses revealed EtG levels ranging between EtG<LOD and 23.39 pg/mg. EtG levels were observed to be <LOD in dental specimens of 6 abstainer cases. A significant correlation was found between EtG levels measured in the dental tissues and MAST outcomes on the statistical analyses (r=0.914).

CONCLUSION

The findings of the present study demonstrated that dental tissue can be used for detection of alcohol intake, using LC/MS/MS.

An overview of alcohol testing and interpretation in the 21st century

Ethanol analysis is the most commonly carried out drug testing in a forensic toxicology laboratory. Determination of blood alcohol concentration (BAC) is needed in a multitude of situations, including in postmortem analysis, driving under the influence (DUI) and drug-facilitated sexual assault (DFSA) cases, workplace drug monitoring, and probation investigations. These analyses are carried out by direct measurement of ethanol concentrations as well as of metabolic by-products, such as ethyl glucuronide (EtG) and ethyl sulfate (EtS). This review article will discuss pharmacokinetics, including absorption, distribution, and elimination of ethanol, methods for the detection of ethanol, the effect of ethanol on human performance, the role of alcohol in injuries and fatalities, and information regarding the interactions that may occur between alcohol and other drugs. Finally, an explanation will be given on how to interpret alcohol levels as well as the extrapolation and calculation of blood alcohol levels at times prior to sample collection.

Post-mortem volatiles of vertebrate tissue

Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted.

May Ingestion of Leachate from Decomposed Corpses Cause Appendicitis? A Case Report

The general consensus is that appendicitis is basically provoked by fecaliths or lymphoid hyperplasic obstruction. Several studies based on histological diagnosis have not confirmed this hypothesis. On the contrary, obstruction has been proved in only a minority of cases. Diverse infections by parasites, bacteria, fungus, and noninfective agents have been associated with appendicitis in the medical literature. We describe a firefighter, who ingested a small quantity of leachate from decomposing corpses while working and developed enteritis a few hours later, which lasted several days and evolved to appendicitis. This case raises the possibility that the high quantity of bacteria concentration present in the leachate could have provoked enteritis and the subsequent appendicitis due to a direct effect of the bacteria on the appendix.