PCR-based detection of salivary bacteria as a marker of expirated blood

Power, Daniel; Cordiner, Stephen J.; Kieser, Jules; Tompkins, Geoffrey R.; Horswell, Jacqui

doi:10.1016/j.scijus.2009.04.006

Cited by 26 publications

(18 citation statements)

References 17 publications

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“…The PCR technique was specific and sensitive enough to identify the presence of oral streptococci in both saliva and expirated blood on a variety of surfaces for up to 92 days after staining. The specificity of this method was similar to data reported with gtf primers or primers to rRNA genes to detect oral streptococci in saliva [15][16][17]. Streptococcal DNA was detected in 99/100 saliva samples, and in another recent study, gtf primers gave PCR product with 20/20 saliva samples [16], indicating that this approach is not affected by differences in the oral microflora of different individuals.…”

Section: Discussionsupporting

confidence: 81%

“…S. sanguinis gtf product was obtained from bloodspots for at least 92 days (cardboard) and 64 days (cotton fabric) after deposit and S. salivarius gtf product after 34 and 29 days. The age of stains in which DNA could be detected was similar to very recent data [17] using primers to rRNA genes to successfully detect streptococci on different fabrics for up to 62 days. No PCR product was obtained with bloodstain patterns that did not contain added saliva, with either the S. salivarius or S. sanguinis gtf primer sets.…”

Section: Pcr Of Expirated Bloodstainssupporting

confidence: 81%

“…This finding was not completely unexpected because it has been shown that saliva can travel up to 184 cm from the mouth of a person who is talking, coughing or laughing [34]. Therefore, small numbers of oral streptococci are probably present on many surfaces that are associated with human use, although their short survival time outside the human mouth (2-6 days) [13,17] means that they may not be viable. However, the amount of streptococcal DNA detected on unstained materials and objects was at least fivefold less than that detected on stained samples (Supplementary Table S2).…”

Section: Discussionmentioning

confidence: 96%

“…Recent research, using either gtf primers or primers for genes encoding ribosomal RNA, has shown that PCR can be used to detect streptococcal DNA in saliva and in bloodsaliva mixtures [16,17]. The purpose of this study was to investigate whether detection of the non-conserved region of the gtf genes could provide a sensitive and specific test for the presence of DNA from oral streptococci in saliva and consequently a potential tool to distinguish mouthexpirated bloodstains from other bloodstains.…”

Section: Introductionmentioning

confidence: 99%

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Using oral microbial DNA analysis to identify expirated bloodspatter

et al. 2010

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Distinguishing expirated bloodstains (blood forced by airflow out of the nose, mouth or a chest wound) from impact spatter (blood from gunshots, explosives, blunt force trauma and/or machinery accidents) is an important challenge in forensic science. Streptococcal bacteria are only found in the human mouth and saliva. This study developed a polymerase chain reaction (PCR) method that detects DNA from these bacteria as a sensitive tool to detect the presence of saliva. The PCR method was very specific to human oral streptococci, with no PCR product being made from human DNA or DNA from other microbes that were tested. It was also very sensitive, detecting as little as 60 fg of target DNA. The PCR amplification gave product with 99 out of 100 saliva samples tested. PCR was not inhibited by the presence of blood and could detect target DNA in expirated bloodstains in a range of materials and for up to 92 days after deposit on cardboard or cotton fabric. In a blind trial, the PCR method was able to distinguish three mock forensic samples that contained expirated blood from four that did not. Our data show that bacteria present in the oral cavity can be detected in bloodstains that contain saliva and therefore can potentially be used as a marker in forensic work to distinguish mouth-expirated bloodstains from other types of bloodstains.

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Section: Discussionsupporting

confidence: 81%

Section: Pcr Of Expirated Bloodstainssupporting

confidence: 81%

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Using oral microbial DNA analysis to identify expirated bloodspatter

et al. 2010

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“…DNAbased techniques have been successfully applied to other areas of forensic science [9] and hold promise for bite mark analysis [6,7,11]. However, recovery of human genomic material from bite marks and saliva stains may be compromised by salivary components that interfere with persistence and amplification of DNA [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Amplification of Oral Streptococcal DNA from Human Incisors and Bite Marks

et al. 2012

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Challenges to the evidentiary value of morphometric determinations have led to a requirement for scientifically substantiated approaches to the forensic analysis of bite marks. Human teeth support genotypically distinctive populations of bacteria that could be exploited for forensic purposes. This study explored the feasibility of directly amplifying bacterial DNA from bite marks for comparison with that from teeth. Samples from self-inflicted experimental bite marks (n = 24) and human incisors were amplified by PCR using primers specific for streptococcal 16S ribosomal DNA. Amplicon profiles (resolved by denaturing gradient gel electrophoresis) from bite mark samples aligned significantly more closely with profiles generated from the teeth responsible than with those from other teeth. Streptococcal amplicons were generated from dental samples applied to excised porcine skin for up to 48 h. These findings indicate that streptococcal DNA can be amplified directly from bite marks, and have potential application in bite mark analysis.

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