ROS-Sensitive Micelles for Controlled Delivery of Antibiotics to Combat Intracellular Staphylococcus aureus-Associated Infections

Author(s):  
Jing Qiao ◽  
Shuolin Cui ◽  
May Xiong

Bacteria can evade the immune system once they are engulfed by phagocytic host cells. This protects them against the bactericidal action of antibiotics and allows the infection to remain latent...

2020 ◽  
Author(s):  
ahmed Al Ghaithi ◽  
Sultan Al Mastari ◽  
John Husband ◽  
Mohammed al kindi ◽  
Atika Al Bimani

AbstractPurposeOsteomyelitis is an infectious bone process leading to bone necrosis and destruction. Published reports on pathogen biofilm thus far have focused on indirect bone resorption mediated by host cells and factors secondary to immune system activation. However, direct bone resorption due to biofilm pathogen has not been adequately studied yet. This study aims to investigate the effect of biofilm pathogen in ex-vivo human bones in the absence of the host immune response using Raman spectroscopy and Scanning electron microscopy.MethodsBone samples collected from patients who underwent knee replacement surgeries were inoculated with Staphylococcus aureus bacteria. Bacterial direct effects on the bone quality were then examined, at various time intervals, using Raman spectroscopy and scanning electron microscopy.ResultsRaman spectroscopy and scanning electron demonstrated the destruction of bone structure and drop in bone quality.ConclusionThis experiment shows the direct effect of bacteria on bone during osteomyelitis in addition to the recognised destruction caused by the host immune system.


2020 ◽  
Vol 14 (4) ◽  
pp. 2219-2234
Author(s):  
Hesham A. Malak ◽  
Hussein H. Abulreesh ◽  
Sameer R. Organji ◽  
Khaled Elbanna ◽  
Mohammed R. Shaaban ◽  
...  

Staphylococcus aureus is a major human pathogen that may cause a wide range of infections and is a frequent cause of soft tissue and bloodstream infections. It is a successful pathogen due to its collective virulence factors and its ability to evade the host immune systems. The review aims to highlight how S. aureus destroys and damage the host cells and explains how immune cells can respond to this pathogen. This review may also provide new insights that may be useful for developing new strategy for combating MRSA and its emerging clones such as community-associated methicillin-resistant S. aureus (CA-MRSA).


Author(s):  
Haibo Peng ◽  
Beibei Xie ◽  
Xianfeng Cen ◽  
Jiaojiao Dai ◽  
Yuanwei Dai ◽  
...  

MRSA can evade the immune system once they are engulfed by phagocytic host cells. This protects them against the bactericidal action of antibiotics and allows the infection to remain latent...


2021 ◽  
Vol 22 (8) ◽  
pp. 4015
Author(s):  
Kyoung Ok Jang ◽  
Youn Woo Lee ◽  
Hangeun Kim ◽  
Dae Kyun Chung

Staphylococcus aureus is a species of Gram-positive staphylococcus. It can cause sinusitis, respiratory infections, skin infections, and food poisoning. Recently, it was discovered that S. aureus infects epithelial cells, but the interaction between S. aureus and the host is not well known. In this study, we confirmed S. aureus to be internalized by HaCaT cells using the ESAT-6-like protein EsxB and amplified within the host over time by escaping host immunity. S. aureus increases the expression of decay-accelerating factor (CD55) on the surfaces of host cells, which inhibits the activation of the complement system. This mechanism makes it possible for S. aureus to survive in host cells. S. aureus, sufficiently amplified within the host, is released through the initiation of cell death. On the other hand, the infected host cells increase their surface expression of UL16 binding protein 1 to inform immune cells that they are infected and try to be eliminated. These host defense systems seem to involve the alteration of tight junctions and the induction of ligand expression to activate immune cells. Taken together, our study elucidates a novel aspect of the mechanisms of infection and immune system evasion for S. aureus.


Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1086
Author(s):  
Francois Helle ◽  
Lynda Handala ◽  
Marine Bentz ◽  
Gilles Duverlie ◽  
Etienne Brochot

Extracellular vesicles have recently emerged as a novel mode of viral transmission exploited by naked viruses to exit host cells through a nonlytic pathway. Extracellular vesicles can allow multiple viral particles to collectively traffic in and out of cells, thus enhancing the viral fitness and diversifying the transmission routes while evading the immune system. This has been shown for several RNA viruses that belong to the Picornaviridae, Hepeviridae, Reoviridae, and Caliciviridae families; however, recent studies also demonstrated that the BK and JC viruses, two DNA viruses that belong to the Polyomaviridae family, use a similar strategy. In this review, we provide an update on recent advances in understanding the mechanisms used by naked viruses to hijack extracellular vesicles, and we discuss the implications for the biology of polyomaviruses.


2017 ◽  
Vol 101 (11) ◽  
pp. 4683-4690 ◽  
Author(s):  
Vi Khanh Truong ◽  
Nipuni Mahanamanam Geeganagamage ◽  
Vladimir A. Baulin ◽  
Jitraporn Vongsvivut ◽  
Mark J. Tobin ◽  
...  

Author(s):  
Tanvir Bamra ◽  
Taj Shafi ◽  
Sushmita Das ◽  
Manjay Kumar ◽  
Manas Ranjan Dikhit ◽  
...  

Summary StatementLeishmania secretes over 151 proteins during in vitro cultivation. Cellular functions of one such novel protein: mevalonate kinase is discussed here; signifying its importance in Leishmania infection.Visceral Leishmaniasis is a persistent infection, caused by Leishmania donovani in Indian subcontinent. This persistence is partly due to phagocytosis and evasion of host immune response. The underlying mechanism involves secretory proteins of Leishmania parasite; however, related studies are meagre. We have identified a novel secretory Leishmania donovani glycoprotein, Mevalonate kinase (MVK), and shown its importance in parasite internalization and immuno-modulation. In our studies, MVK was found to be secreted maximum after 1 h temperature stress at 37°C. Its secretion was increased by 6.5-fold in phagolysosome-like condition (pH ~5.5, 37°C) than at pH ~7.4 and 25°C. Treatment with MVK modulated host immune system by inducing interleukin-10 and interleukin-4 secretion, suppressing host’s ability to kill the parasite. Peripheral blood mononuclear cell (PBMC)-derived macrophages infected with mevalonate kinase-overexpressing parasites showed an increase in intracellular parasite burden in comparison to infection with vector control parasites. Mechanism behind the increase in phagocytosis and immunosuppression was found to be phosphorylation of mitogen-activated protein (MAP) kinase pathway protein, Extracellular signal-regulated kinases-1/2, and actin scaffold protein, cortactin. Thus, we conclude that Leishmania donovani Mevalonate kinase aids in parasite engulfment and subvert the immune system by interfering with signal transduction pathways in host cells, which causes suppression of the protective response and facilitates their persistence in the host. Our work elucidates the involvement of Leishmania in the process of phagocytosis which is thought to be dependent largely on macrophages and contributes towards better understanding of host pathogen interactions.


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