All Yersinia enterocolitica are pathogenic: virulence of phylogroup 1 Y. enterocolitica in a Galleria mellonella infection model.

Yersinia enterocolitica is a zoonotic pathogen and a common cause of gastroenteritis in humans. The species is composed of six diverse phylogroups, of which strains of phylogroup 1 are considered non-pathogenic to mammals due to the lack of the major virulence plasmid pYV, and their lack of virulence in a mouse infection model. In the present report we present data examining the pathogenicity of strains of Y. enterocolitica across all six phylogroups in a Galleria mellonellla model. We have demonstrated that in this model strains of phylogroup 1 exhibit severe pathogenesis with a lethal dose of as low as 10 c.f.u., that this virulence is an active process and that flagella play a major role in the virulence phenotype. We have also demonstrated that the complete lack of virulence in Galleria of the mammalian pathogenic phylogroups is not due to carriage of the pYV virulence plasmid. Our data suggest that all Y. enterocolitica can be pathogenic, which may be a reflection of the true natural habitat of the species, and that we may need to reconsider the eco-evo perspective of this important bacterial species

Ilimaquinone (Marine Sponge Metabolite) Induces Apoptosis in HCT-116 Human Colorectal Carcinoma Cells via Mitochondrial-Mediated Apoptosis Pathway

Ilimaquinone (IQ), a metabolite found in marine sponges, has been reported to have a number of biological properties, including potential anticancer activity against colon cancer. However, no clear understanding of the precise mechanism involved is known. The aim of this study was to examine the molecular mechanism by which IQ acts on HCT-116 cells. The anticancer activity of IQ was investigated by means of a cell viability assay followed by the determination of induction of apoptosis by means of the use of acridine orange–ethidium bromide (AO/EB) staining, Annexin V/PI double staining, DNA fragmentation assays, and TUNEL assays. The mitochondrial membrane potential (ΔΨm) was detected using the JC-1 staining technique, and the apoptosis-associated proteins were analyzed using real-time qRT-PCR. A molecular docking study of IQ with apoptosis-associated proteins was also conducted in order to assess the interaction between IQ and them. Our results suggest that IQ significantly suppressed the viability of HCT-116 cells in a dose-dependent manner. Fluorescent microscopy, flow cytometry, DNA fragmentation and the TUNEL assay in treated cells demonstrated apoptotic death mode. As an additional confirmation of apoptosis, the increased level of caspase-3 and caspase-9 expression and the downregulation of Bcl-2 and mitochondrial dysfunction were observed in HCT-116 cells after treatment with IQ, which was accompanied by a decrease in mitochondrial membrane potential (ΔΨm). Overall, the results of our studies demonstrate that IQ could trigger mitochondria-mediated apoptosis as demonstrated by a decrease in ΔΨm, activation of caspase-9/-3, damage of DNA and a decrease in the proportion of Bcl-2 through the mitochondrial-mediated apoptosis pathway

Genomic Characterization of Uropathogenic <i>Escherichia coli</i> Isolates from Tertiary Hospitals in Riyadh, Saudi Arabia

Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infections (UTIs) in hospitalised and non-hospitalised patients. Genomic analysis was used to gain further insight into the molecular characteristics of UPEC isolates from Saudi Arabia. A total of 165 isolates were collected from patients with UTIs between May 2019 and September 2020 from two tertiary hospitals in Riyadh, Saudi Arabia. Identification and antimicrobial susceptibility testing (AST) were performed using the VITEK system. Extended-spectrum β-lactamase (ESBL)-producing isolates (n = 48) were selected for whole genome sequencing (WGS) analysis. In silico analysis revealed that the most common sequence types detected were ST131 (39.6%), ST1193 (12.5%), ST73 (10.4%), and ST10 (8.3%). Our finding showed that blaCTX-M-15 gene was detected in the majority of ESBL isolates (79.2%), followed by blaCTX-M-27 (12.5%) and blaCTX-M-8 (2.1%). ST131 carried blaCTX-M-15 or blaCTX-M-27, and all ST73 and ST1193 carried blaCTX-M-15. The relatively high proportion of ST1193 in this study was notable as a newly emerged lineage in the region, which warrants further monitoring