The tst gene associated Staphylococcus aureus pathogenicity island facilitates its pathogenesis by promoting the secretion of inflammatory cytokines and inducing immune suppression

In this study, we investigated the prevalence of the tst gene in clinical isolates of S. aureus. Then, animal experiments were performed to further evaluate the influence of the presence of the tst gene associated Staphylococcus aureus Pathogenicity Island (SaPI) on body weight, serum cytokine concentrations and the bacterial load in different organs. In addition, macrophages were used to analyze the secretion of cytokines in vitro and bacterial survival in the cytoplasm. Finally, pathological analysis was carried out to evaluate organ tissue impairment. The results demonstrated that the prevalence of tst gene was approximately 17.8% of the bacterial strains examined. BALB/c mice infected with tst gene associated SaPI positive isolates exhibited a severe loss of body weight and a high bacterial load in the liver, heart, kidney and spleen. Pathological analysis demonstrated that tissue impairment was more severe after infection with tst gene associated SaPI positive isolates. Moreover, the secretion of IL-6, IL-2 and IL17A by macrophages infected with tst gene associated SaPI positive isolates clearly increased. Notably, IL-6 secretion in BALB/c mice infected with tst gene associated SaPI positive isolates was higher than that in BALB/c mice infected with negative ones. Together, these results indicated that the tst gene associated SaPI may play a critical role in the pathological process of infection via a direct and persistent toxic function, and by promoting the secretion o...
Source: Microbial Pathogenesis - Category: Infectious Diseases Source Type: research

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Foods may potentially serve as vehicles for the transmission of antimicrobial-resistant variants of Staphylococcus aureus that are important in a human clinical context. Further, retail food products can be a cause of staphylococcal food poisoning. For these reasons and to account for source attribution and risk assessment, detailed information on the population structure, resistance, and virulence profiles of S. aureus originating from retail food products is necessary. In the current study, whole-genome sequences from 88 S. aureus isolates were subjected to bioinformatics analyses in relation to sequence types, antimicro...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
AbstractHistorically, vancomycin has been considered a primary therapeutic option for treating infections withStaphylococcus aureus, but isolates with reduced vancomycin susceptibility (SA-RVS) (MIC  ≥ 4 μg/mL) have emerged. Telavancin, a semisynthetic lipoglycopeptide, is an alternative treatment option forS. aureus, but data examining telavancin activity against SA-RVS are limited. In the present study, we characterize 300 isolates ofS. aureus isolates (50 vancomycin-susceptible (VSSA) isolates and 250 SA-RVS isolates) from a large tertiary care, academic medical center, 51.8% of which were methi...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research
Conclusions: Both host-related factors, increased Pitt bacteremia score and advanced age, as well as a pathogen-related factor, carriage of tst-1 by causative MRSA isolates, were risk factors for two-week mortality in patients with BSIs, and careful management of patients with BSIs caused by the New York/Japan epidemic clone is needed to improve clinical outcomes. PMID: 31501145 [PubMed - as supplied by publisher]
Source: Antimicrobial Agents and Chemotherapy - Category: Microbiology Authors: Tags: Antimicrob Agents Chemother Source Type: research
The toxic shock syndrome toxin-1 (TSST-1), encoded by tst gene, has been proposed to cause staphylococcal toxic shock syndrome (TSS) in a susceptible host, which highlights the need to evaluate the level of tst gene expression and molecular genetic characteristics of the tst-positive isolates. A total of 916 S. aureus isolates collected from seven hospitals in China were screened for the tst gene. The tst positive isolates were characterized by spa, SCCmec, PFGE and agr typing. Representative strains were also subjected to MLST typing. qRT-PCR was used to quantify tst and major virulence regulator genes expression. We also...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
This study identified prophages as mediators of bacterial virulence in a model of infectious endocarditis, probably through promotion of interaction with extracellular matrix components. Further studies are needed to identify mechanisms leading to promotion of intrinsic virulence. Introduction Challenges related to Staphylococcus aureus infections in the human and veterinary clinics mobilized important human and technical resources. S. aureus can colonize 20–30% of the general population asymptomatically but is also capable of causing a wide spectrum of diseases ranging from benign infections, to particularly...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
CONCLUSIONS: We conclude that, due to its ability to suppress toxin production, iclaprim should be effective against severe staphylococcal infections caused by toxin-producing MRSA and VISA strains, especially given its ability to concentrate at sites of infection such as skin and skin structures and the lung. PMID: 30676310 [PubMed - as supplied by publisher]
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research
Conclusions: SCCmec type IV and the pvl genes were common among the MRSA isolates from the community. The hla gene was found infrequently, but none of the isolates possessed the tst 1 gene. Knowledge of this is important for robust surveillance of such cases from the community in the country.
Source: Nigerian Journal of Clinical Practice - Category: Rural Health Authors: Source Type: research
Authors: Kitagawa H, Ohge H, Hisatsune J, Kajihara T, Katayama K, Takahashi S, Sueda T, Sugai M Abstract The emergence of a Japan-intrinsic community associated methicillin-resistant Staphylococcus aureus strain (CA-MRSA/J) has been reported. A 70-year-old man with recurrent colon cancer and a history of mitral valve replacement was admitted to the hospital in a state of shock. He was diagnosed with prosthetic valve endocarditis (PVE) caused by MRSA and underwent cardiac surgery. The MRSA isolates belonged to multilocus sequence type 8 and carried staphylococcal cassette chromosome mec IVl and the genes of toxic sh...
Source: Internal Medicine - Category: Internal Medicine Tags: Intern Med Source Type: research
Discussion: The genomic diversity of Gaza ST22 isolates is not consistent with recent emergence in the region. The results indicate that two divergent Gaza clones evolved separately from susceptible isolates. Researchers should not assume that isolates identified as ST22 in the community are examples of EMRSA-15 that have escaped their healthcare roots. Future surveillance of MRSA is essential to the understanding of ST22 evolutionary dynamics and to aid efforts to slow the further spread of this lineage. PMID: 30153881 [PubMed - in process]
Source: Euro Surveill - Category: Infectious Diseases Authors: Tags: Euro Surveill Source Type: research
Publication date: March 2018Source: Beni-Suef University Journal of Basic and Applied Sciences, Volume 7, Issue 1Author(s): Cajethan Ezeamagu, Irene Imanatue, Margaret Dosunmu, Adebola Odeseye, Glory Baysah, Daniel Aina, Foluke Odutayo, Grace Mensah-AgyeiAbstractMethicillin-resistant Staphylococcus aureus is a problem in both healthcare institutions and community settings. This is due to its multi-drug resistant challenges. Hence, this study assessed the prevalence of methicillin resistant gene (mecA), exfoliative toxin (eta and etb) and toxic shock syndrome (tsst-1) genes in S. aureus isolated from clinical samples. A tot...
Source: Beni Suef University Journal of Basic and Applied Sciences - Category: Science Source Type: research
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