Project description:WGS of HA-MRSA isolates from Saudi Arabia done to characterize strain's genotypes, AMR and virulence genes, transposons and possible phylodynamics.
Project description:Introduction Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are increasingly isolated, with USA300-0114 being the predominant clone in the USA. Comparative whole genome sequencing of USA300 isolates collected in 2002, 2003 and 2005 showed a limited number of single nucleotide polymorphisms and regions of difference. This suggests that USA300 has undergone rapid clonal expansion without great genomic diversification. However, whole genome comparison of CA-MRSA has been limited to isolates belonging to USA300. The aim of this study was to compare the genetic repertoire of different CA-MRSA clones with that of HA-MRSA from the USA and Europe through comparative genomic hybridization (CGH) to identify genetic clues that may explain the successful and rapid emergence of CA-MRSA. Materials and Methods Hierarchical clustering based on CGH of 48 MRSA isolates from the community and nosocomial infections from Europe and the USA revealed dispersed clustering of the 19 CA-MRSA isolates. This means that these 19 CA-MRSA isolates do not share a unique genetic make-up. Only the PVL genes were commonly present in all CA-MRSA isolates. However, 10 genes were variably present among 14 USA300 isolates. Most of these genes were present on mobile elements. Conclusion The genetic variation present among the 14 USA300 isolates is remarkable considering the fact that the isolates were recovered within one month and originated from a confined geographic area, suggesting continuous evolution of this clone. Data is also available from <ahref=http://bugs.sgul.ac.uk/E-BUGS-108 target=_blank>BuG@Sbase</a>
Project description:Previous studies have documented the diversity of genetic background of methicillin-resistant S. aureus (MRSA) strains associated with healthcare (HA-MRSA), community (CA-MRSA) and livestock (LA-MRSA). The accessory and core-variable genome content of those strains remain largely unknown. To compare the composition of accessory and core-variable genome of Belgian MRSA strains according to host, population setting and genetic background, representative strains of HA- (n=21), CA- (n = 13) and ST398 LA-MRSA (n = 18) were characterized by a DNA-microarray (StaphVar Array) composed of oligonucleotide probes targeting ~400 resistance, adhesion and virulence associated genes.ST398 strains displayed very homogenous hybridization profiles (>94% gene content homology) irrespective of their host origin. This “ST398-specific” genomic profile was not distantly demarked from those of certain human-associated lineages but lacked several virulence- and colonization-associated genes harbored by strains of human origin, such as genes encoding proteases, haemolysins or adhesins. No enterotoxin gene was found among ST398 strains. In conclusion, our findings are consistent with a non-human origin of this ST398 lineage but suggest that it might have the potential to adapt further to the human host.
Project description:Staphylococcus aureus can cause a broad spectrum of diseases that vary widely in clinical presentation and disease severity[121]. Methicillin-Resistant S. aureus (MRSA) strains first described in the 1960’s[122] were hospital acquired (HA MRSA), however in the 1990’s, community-associated MRSA strains (CA MRSA) were identified and are considered to be more virulent[16]. Therapeutics and management of MRSA focuses on novel antibacterials and vaccines targeting virulence factors. To date no clinical trials for vaccines have succeeded[123] due to the poor understanding of the pathogenic mechanisms exhibited by S.aureus.We investigated the differential gene expression of four clinical MRSA strains in vitro, belonging to HA and CA MRSA, at the stationary and exponential growth phases, using RNA-seq on the Ion torrent next generation sequencing platform. This study reveals the high diversity of virulence trait expression among MRSA strains within strains as well as between different growth phases, and also suggests potential factors other than PVL that contributes to enhanced virulence in CA MRSA
Project description:Klinefelter syndrome (KS) is the most prevalent aneuploidy in males and is characterized by an extra copy of the X chromosome,while the non-mosaic form of KS with 47,XXY karyotype is the most frequent (80-90%), less common non-disjunction events during the early mitotic division of the zygote result in mosaic forms of KS (47,XXY/46,XY). Here, using a paradigmatic cohort of KS-inducible pluripotent stem cells (iPSCs) carrying 47,XXY karyotypes we present the first iPSC-based disease-modeling study performed on KS patients from Saudi Arabia. We profiled the transcriptome of these Saudi KS-iPSCs, virtually characterized by subduedcgenetic backgrounds. Moreover, we performed a comparative transcriptomic analysis to assess the aberrant gene expression profile due to X dosage imbalance in four Saudi and five European and North American 47,XXY patients-derived iPSCs from our previously published study on KS and high-grade sex chromosome aneuploidies (SCAs). We identified a transcriptomic signature including ten PAR1 genes and thirteen non-PAR escape genes consistently upregulated in KS compared to 46,XY controls in both groups, as well as 193 consistenty disregulated autosomal genes. Our results indicate that the global transcriptional impact of X chromosome overdosage in KS is largely attributable to X-linked genes escaping X inactivation, regardless of the geographical area of origin, ethnicity, and genetic background.
2023-08-02 | GSE220268 | GEO
Project description:Population structure of invasive MRSA in Saudi Arabia hospitals with genomic epidemiology approaches