METHODS: We analysed the cancerous and adjacent non-cancerous formalin-fixed paraffin embedded (FFPE) tissue of 83 CRC patients from a single medical centre in Malaysia. TaqMan probe-based qPCR targeting the 16S rRNA gene was used to detect the presence of FN in the extracted FFPE DNA. The differences in FN expression between cancer and non-cancer tissues were evaluated. Association studies between FN infection in the tumour and relative FN abundance with available clinical data were conducted.
RESULTS: FN was more abundant in the cancerous tissue compared to non-cancerous tissue (p = 0.0025). FN infection in the tumour was significantly associated with lymph node metastasis (p = 0.047) and cancer staging (p = 0.032), but not with other clinicopathologic variables. In double-positive patients where FN was detected in both cancerous and non-cancerous tissue, the expression fold-change of FN, calculated using 2-ΔΔCT formula, was significantly higher in patients with tumour size equal to or greater than 5 cm (p = 0.033) and in KRAS-mutated patients (p = 0.046).
CONCLUSIONS: FN is enriched in CRC tumour tissue and is associated with tumour size, lymph node metastasis, cancer staging, and KRAS mutation in this single-centre small cohort study.
RESULTS: To investigate the genomic properties and taxonomic status of these strains, we employed both 16S rRNA Sanger sequencing and whole-genome sequencing using the Illumina HiSeq X Ten platform with PE151 (paired-end) sequencing. Our analyses revealed that the draft genome of Actinomyces acetigenes ATCC 49340 T was 3.27 Mbp with a 68.0% GC content, and Actinomyces stomatis ATCC 51655 T has a genome size of 3.08 Mbp with a 68.1% GC content. Multi-locus (atpA, rpoB, pgi, metG, gltA, gyrA, and core genome SNPs) sequence analysis supported the phylogenetic placement of strains ATCC 51655 T and ATCC 49340 T as independent lineages. Digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), and average amino acid identity (AAI) analyses indicated that both strains represented novel Actinomyces species, with values below the threshold for species demarcation (70% dDDH, 95% ANI and AAI). Pangenome analysis identified 5,731 gene clusters with strains ATCC 49340 T and ATCC 51655 T possessing 1,515 and 1,518 unique gene clusters, respectively. Additionally, genomic islands (GIs) prediction uncovered 24 putative GIs in strain ATCC 49340 T and 16 in strain ATCC 51655 T, contributing to their genetic diversity and potential adaptive capabilities. Pathogenicity analysis highlighted the potential human pathogenicity risk associated with both strains, with several virulence-associated factors identified. CRISPR-Cas analysis exposed the presence of CRISPR and Cas genes in both strains, indicating these strains might evolve a robust defense mechanism against them.
CONCLUSION: This study supports the classification of strains ATCC 49340 T and ATCC 51655 T as novel species within the Actinomyces, in which the name Actinomyces acetigenes sp. nov. (type strain ATCC 49340 T = VPI D163E-3 T = CCUG 34286 T = CCUG 35339 T) and Actinomyces stomatis sp. nov. (type strain ATCC 51655 T = PK606T = CCUG 33930 T) are proposed.
ANIMALS: A convention on international trade in endangered species (CITES) of wild fauna and flora registered crocodile farm, provided a healthy male saltwater crocodile, Crocodylus porosus for this study.
PROCEDURES: Three samples were taken from the oral cavity, 3 samples from the proximal region of the small intestine (jejunum), and 3 samples from the distal part of the large intestine of the gastrointestinal tract of C. porosus were obtained using sterile cotton swabs. Next, swabs were placed in 15 mL sterile centrifuge tubes, individually, and kept on ice for immediate transportation to the laboratory. This was followed by 16S rRNA gene analysis using specific primers (341F-CCTAYGGGRBGCASCAG, and 806R-GGACTACNNGGGTATCTAAT). Amplicons were sequenced on Illumina paired-end platform, and bacterial gastrointestinal communities, the relative abundance of taxa, and principal component and coordinate analysis were performed.
RESULTS: The findings revealed that bacterial community structures from differing regions exhibited several differences. The number of observed bacterial operational taxonomic units (OTUs) was 153 in the oral cavity, 239 in the small intestine, and 119 in the large intestine of C. porosus. The small intestine reflects the highest richness. In contrast, the large intestine exhibited the least richness of microbial communities. Relative abundance of taxa showed that Proteobacteria, Bacteroidetes, and Firmicutes were dominant in all 3 sample sites. Pseudomonas differed in the oral cavity and the large intestine, with the latter exhibiting less distribution of Pseudomonas. Stenotrophomonas and Castellaniella were higher in the oral cavity, while the relative abundance of Comamonas and Salmonella was higher in the small intestine. Conversely, the relative abundance of Salmonella and Pannonibacter was augmented in the large intestine.
CLINICAL RELEVANCE: For the first time, this study demonstrates the bacterial diversity along the segments of the gastrointestinal tract of C. porosus. Bacterial flora varies throughout the gastrointestinal tract. Although further studies using large cohorts are warranted; however, our findings suggest that microbiome composition may have the potential as a biomarker in determining the overall health and well-being of C. porosus.