Bacteriological profiles of skin flora on early cadaver
Post-mortem microbiology (PMM) has gained significant importance in the forensic department nowadays to determine the actual cause of death of adults and infants, especially for deaths caused by infection. PMM is of utmost importance when the cadaver does not show any apparent signs of infection....
| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2022
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/116649/ http://psasir.upm.edu.my/id/eprint/116649/1/116649.pdf |
| _version_ | 1848867058477957120 |
|---|---|
| author | Chong, Chi Kwan |
| author_facet | Chong, Chi Kwan |
| author_sort | Chong, Chi Kwan |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Post-mortem microbiology (PMM) has gained significant importance in the forensic
department nowadays to determine the actual cause of death of adults and infants,
especially for deaths caused by infection. PMM is of utmost importance when the
cadaver does not show any apparent signs of infection. An infective that leads to death
is usually suspected in sudden death. Therefore, the determination of infective cause can
help in further management of pathogenic transmission and is thus able to prevent the
occurrence of outbreaks. However, the current challenge in PMM is the difficulty in
interpreting culture results, for example, differentiating the true pathogen from the
contaminants, especially when there is a mixed growth in the samples. Mixed growth or
contamination from skin flora may induce false positive results, leading to uncertainty
and failure in identifying true pathogen. Therefore, information on post-mortem skin
flora can be helpful in providing references for interpreting microbiological
investigations in post-mortem cases. Early cadavers (n=39), which have an estimated
post-mortem (ePMI) of less than 24 hours, under sudden unexpected death cases, were
included in this study. Two body sites, namely the neck and femoral, of each cadaver
were chosen as the sites to obtain skin samples. Blood samples from these two sites were
routinely obtained for post-mortem microbiological culture. Cotton swabs were
moistened with normal saline and were then rubbed vigorously and rotated to ensure that
homogeneity in the skin areas were achieved by each swab. The swabs were then kept in
200μl of phosphate-buffered saline (PBS) for storage and transportation. DNA was
extracted from each skin swab and high-throughput 16S rRNA sequencing was
performed on the extracted DNA using the Illumina Miseq system to assess bacterial
diversity and abundance. The sequence outputs were analysed by using the LotuS
pipeline while the α-diversity and β-diversity were analysed by using the Quantitative
Insights into Microbial Ecology (QIIME) software. The samples were mostly
predominated by phylum Proteobacteria (61.20%), followed by Firmicutes (28.10%),
Actinobacteria (10.00%) and Bacteroidetes (0.60%). In addition, the top 10 dominant
genera from the samples were Ochrobactrum (24.70%), Staphylococcus (20.60%), other
members of Enterobacteriaceae (17.70%), Corynebacterium (6.00%), Enhydrobacter
(5.30%), Acinetobacter (4.30%), Klebsiella (3.40%), Pseudomonas (2.70%), Stenotrophomonas (2.10%) and Phycicoccus (2.00%) accordingly. Moreover, there were
no statistical difference between the bacterial communities of the neck and femoral sites,
except for genus Corynebacterium which showed significant difference in abundance
between both body sites. Nevertheless, the results showed significant difference between
the abundance of some bacterial genera found on the cadavers with ePMI less than 5
hours (ePMI<5H) and the cadavers with ePMI more than 5 hours (ePMI>5H). The
findings of this study provides data on the known skin flora that presents on early
cadavers, thus may help in determining the actual cause of death due to pathogenic
infections. |
| first_indexed | 2025-11-15T14:30:28Z |
| format | Thesis |
| id | upm-116649 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T14:30:28Z |
| publishDate | 2022 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-1166492025-05-27T01:38:01Z http://psasir.upm.edu.my/id/eprint/116649/ Bacteriological profiles of skin flora on early cadaver Chong, Chi Kwan Post-mortem microbiology (PMM) has gained significant importance in the forensic department nowadays to determine the actual cause of death of adults and infants, especially for deaths caused by infection. PMM is of utmost importance when the cadaver does not show any apparent signs of infection. An infective that leads to death is usually suspected in sudden death. Therefore, the determination of infective cause can help in further management of pathogenic transmission and is thus able to prevent the occurrence of outbreaks. However, the current challenge in PMM is the difficulty in interpreting culture results, for example, differentiating the true pathogen from the contaminants, especially when there is a mixed growth in the samples. Mixed growth or contamination from skin flora may induce false positive results, leading to uncertainty and failure in identifying true pathogen. Therefore, information on post-mortem skin flora can be helpful in providing references for interpreting microbiological investigations in post-mortem cases. Early cadavers (n=39), which have an estimated post-mortem (ePMI) of less than 24 hours, under sudden unexpected death cases, were included in this study. Two body sites, namely the neck and femoral, of each cadaver were chosen as the sites to obtain skin samples. Blood samples from these two sites were routinely obtained for post-mortem microbiological culture. Cotton swabs were moistened with normal saline and were then rubbed vigorously and rotated to ensure that homogeneity in the skin areas were achieved by each swab. The swabs were then kept in 200μl of phosphate-buffered saline (PBS) for storage and transportation. DNA was extracted from each skin swab and high-throughput 16S rRNA sequencing was performed on the extracted DNA using the Illumina Miseq system to assess bacterial diversity and abundance. The sequence outputs were analysed by using the LotuS pipeline while the α-diversity and β-diversity were analysed by using the Quantitative Insights into Microbial Ecology (QIIME) software. The samples were mostly predominated by phylum Proteobacteria (61.20%), followed by Firmicutes (28.10%), Actinobacteria (10.00%) and Bacteroidetes (0.60%). In addition, the top 10 dominant genera from the samples were Ochrobactrum (24.70%), Staphylococcus (20.60%), other members of Enterobacteriaceae (17.70%), Corynebacterium (6.00%), Enhydrobacter (5.30%), Acinetobacter (4.30%), Klebsiella (3.40%), Pseudomonas (2.70%), Stenotrophomonas (2.10%) and Phycicoccus (2.00%) accordingly. Moreover, there were no statistical difference between the bacterial communities of the neck and femoral sites, except for genus Corynebacterium which showed significant difference in abundance between both body sites. Nevertheless, the results showed significant difference between the abundance of some bacterial genera found on the cadavers with ePMI less than 5 hours (ePMI<5H) and the cadavers with ePMI more than 5 hours (ePMI>5H). The findings of this study provides data on the known skin flora that presents on early cadavers, thus may help in determining the actual cause of death due to pathogenic infections. 2022-01 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/116649/1/116649.pdf Chong, Chi Kwan (2022) Bacteriological profiles of skin flora on early cadaver. Masters thesis, Universiti Putra Malaysia. http://ethesis.upm.edu.my/id/eprint/18290 Forensic Microbiology |
| spellingShingle | Forensic Microbiology Chong, Chi Kwan Bacteriological profiles of skin flora on early cadaver |
| title | Bacteriological profiles of skin flora on early cadaver |
| title_full | Bacteriological profiles of skin flora on early cadaver |
| title_fullStr | Bacteriological profiles of skin flora on early cadaver |
| title_full_unstemmed | Bacteriological profiles of skin flora on early cadaver |
| title_short | Bacteriological profiles of skin flora on early cadaver |
| title_sort | bacteriological profiles of skin flora on early cadaver |
| topic | Forensic Microbiology |
| url | http://psasir.upm.edu.my/id/eprint/116649/ http://psasir.upm.edu.my/id/eprint/116649/ http://psasir.upm.edu.my/id/eprint/116649/1/116649.pdf |