Capsule-deficient group A evades autophagy-mediated killing in macrophages.

Unlabelled: The hyaluronic acid capsule is crucial in protecting group A (GAS) against phagocytic killing. However, there have been reported outbreaks caused by capsule-deficient GAS strains, and the mechanisms underlying their evasion of immune clearance remain unclear. This study demonstrated that the capsule-deficient mutant [Cap(-)] of the strain increased survival within phagocytic cells compared to the wild-type strain [Cap(+)].

Conserved molecular chaperone PrsA stimulates protective immunity against group A Streptococcus.

Group A Streptococcus (GAS) is a significant human pathogen that poses a global health concern. However, the development of a GAS vaccine has been challenging due to the multitude of diverse M-types and the risk of triggering cross-reactive immune responses. Our previous research has identified a critical role of PrsA1 and PrsA2, surface post-translational molecular chaperone proteins, in maintaining GAS proteome homeostasis and virulence traits.

, an emerging pathogen that induces lipid raft-mediated cytotoxicity.

is an emerging spore-forming anaerobe that is often observed in -associated inflammatory bowel disease (IBD) exacerbations. Unlike , neither produces toxins nor possesses toxin-encoding genetic loci, but is commonly found in both intestinal and extra-intestinal infections. Membrane lipid rafts are composed of dynamic assemblies of cholesterol and sphingolipids, allowing bacteria to gain access to cells.

RopB-regulated SpeB cysteine protease degrades extracellular vesicles-associated streptolysin O and bacterial proteins from group A .

Extracellular vesicles (EVs) can be released from gram-positive bacteria and would participate in the delivery of bacterial toxins. (group A , GAS) is one of the most common pathogens of monomicrobial necrotizing fasciitis. Spontaneous inactivating mutation in the CovR/CovS two-component regulatory system is related to the increase of EVs production via an unknown mechanism.

RopB represses the transcription of in the absence of SIP in group A .

RopB is a quorum-sensing regulator that binds to the SpeB-inducing peptide (SIP) under acidic conditions. SIP is known to be degraded by the endopeptidase PepO, whose transcription is repressed by the CovR/CovS two-component regulatory system. Both SIP-bound RopB (RopB-SIP) and SIP-free RopB (apo-RopB) can bind to the promoter; however, only RopB-SIP activates transcription.

The Bacterial Markers of Identification of Invasive CovR/CovS-Inactivated Group A .

Necrotizing fasciitis is a severe infectious disease that results in significant mortality. Streptococcus pyogenes (group A Streptococcus, GAS) is one of the most common bacterial pathogens of monomicrobial necrotizing fasciitis. The early diagnosis of necrotizing fasciitis is crucial; however, the typical cutaneous manifestations are not always presented in patients with GAS necrotizing fasciitis, which would lead to miss- or delayed diagnosis.

Incidence and Effects of Acquisition of the Phage-Encoded Superantigen Gene in Invasive Group A .

The acquisition of the phage-encoded superantigen by scarlet fever-associated group A (, GAS) is found in North Asia. Nonetheless, the impact of acquiring by GAS in invasive infections is unclear. This study initially analyzed the prevalence of + GAS among isolates from sterile tissues and blood.

PM impairs macrophage functions to exacerbate pneumococcus-induced pulmonary pathogenesis.

Background: Pneumococcus is one of the most common human airway pathogens that causes life-threatening infections. Ambient fine particulate matter (PM) with aerodynamic diameter ≤ 2.5 μm (PM) is known to significantly contribute to respiratory diseases.

RocA Regulates Phosphatase Activity of Virulence Sensor CovS of Group A in Growth Phase- and pH-Dependent Manners.

The control of the virulence response regulator and sensor (CovR-CovS) two-component regulatory system in group A (GAS) strains regulates more than 15% of gene expression and has critical roles in invasive GAS infection. The membrane-embedded CovS has kinase and phosphatase activities, and both are required for modulating the phosphorylation level of CovR. Regulator of Cov (RocA) is a positive regulator of and also been shown to be a pseudokinase that interacts with CovS to enhance the phosphorylation level of CovR; however, how RocA modulates the activity of CovS has not been determined conclusively.

Nicotinamide Increases Intracellular NAD Content to Enhance Autophagy-Mediated Group A Streptococcal Clearance in Endothelial Cells.

Group A streptococcus (GAS) is a versatile pathogen that causes a wide spectrum of diseases in humans. Invading host cells is a known strategy for GAS to avoid antibiotic killing and immune recognition. However, the underlying mechanisms of GAS resistance to intracellular killing need to be explored.

Rapid analysis of bacterial composition in prosthetic joint infection by 16S rRNA metagenomic sequencing.

Objectives: Prosthetic joint infection (PJI) is the most common cause of arthroplasty failure. However, infection is often difficult to detect by conventional bacterial cultures, for which false-negative rates are 23% to 35%. In contrast, 16S rRNA metagenomics has been shown to quantitatively detect unculturable, unsuspected, and unviable pathogens.

Effect of Phosphatase Activity of the Control of Virulence Sensor (CovS) on Clindamycin-Mediated Streptolysin O Production in Group A .

Severe manifestations of group A (GAS) infections are associated with massive tissue destruction and high mortality. Clindamycin (CLI), a bacterial protein synthesis inhibitor, is recommended for treating patients with severe invasive GAS infection. Nonetheless, the subinhibitory concentration of CLI induces the production of GAS virulent exoproteins, such as streptolysin O (SLO) and NADase, which would enhance bacterial virulence and invasiveness.

Phosphorylation at the D53 but Not the T65 Residue of CovR Determines the Repression of and Transcription in 1- and 49-Type Group A Streptococci.

CovR/CovS is a two-component regulatory system in group A and primarily acts as a transcriptional repressor. The D53 residue of CovR (CovR) is phosphorylated by the sensor kinase CovS, and the phosphorylated CovR protein binds to the intergenic region of to inhibit transcription. Nonetheless, the transcription of and is suppressed in mutants.

NAD-Glycohydrolase Depletes Intracellular NAD and Inhibits Acidification of Autophagosomes to Enhance Multiplication of Group A in Endothelial Cells.

Group A (GAS) is a human pathogen causing a wide spectrum of diseases, from mild pharyngitis to life-threatening necrotizing fasciitis. GAS has been shown to evade host immune killing by invading host cells. However, how GAS resists intracellular killing by endothelial cells is still unclear.

PERK Signal-Modulated Protein Translation Promotes the Survivability of Dengue 2 Virus-Infected Mosquito Cells and Extends Viral Replication.

Survival of mosquitoes from dengue virus (DENV) infection is a prerequisite of viral transmission to the host. This study aimed to see how mosquito cells can survive the infection during prosperous replication of the virus. In C6/36 cells, global protein translation was shut down after infection by DENV type 2 (DENV2).

Acidic stress enhances CovR/S-dependent gene repression through activation of the covR/S promoter in emm1-type group A Streptococcus.

Streptococcus pyogenes (group A Streptococcus) is a clinically important gram-positive bacterium that causes severe diseases with high mortality. Spontaneous mutations in genes encoding the CovR/CovS two-component regulatory system have been shown to derepress expression of virulence factors and are significantly associated with invasiveness of infections. Sensor kinase CovS senses environmental signals and then regulates the levels of phosphorylated CovR.

Cytolethal Distending Toxin Enhances Radiosensitivity in Prostate Cancer Cells by Regulating Autophagy.

Cytolethal distending toxin (CDT) produced by contains three subunits: CdtA, CdtB, and CdtC. Among these three toxin subunits, CdtB is the toxic moiety of CDT with DNase I activity, resulting in DNA double-strand breaks (DSB) and, consequently, cell cycle arrest at the G2/M stage and apoptosis. Radiation therapy is an effective modality for the treatment of localized prostate cancer (PCa).

Repression of Rgg But Not Upregulation of LacD.1 in -type Mutant Mediates the SpeB Repression in Group A .

CovR/CovS is an important two-component regulatory system in human pathogen group A (GAS). Epidemiological studies have shown that inactivation of the sensor kinase CovS is correlated with invasive clinical manifestations. The phosphorylation level of response regulator CovR decreases dramatically in the absence of CovS, resulting in the derepression of virulence factor expression and an increase in bacterial invasiveness.