Virulence factors Archives

Virulence factors, Pathogenesis and Clinical manifestations of Legionella pneumophila

May 12, 2020January 15, 2018 by Sagar Aryal

Virulence factors of Legionella pneumophila Heat shock protein 60: enhances invasion and cytokine expression in macrophages. Outer membrane protein: binding with and delivery of packaged materials into the eukaryotic cells. inhibit the fusion of phagosomes with lysosomes. Macrophage infectivity potentiator (Mip) protein promotes adherence and phagocytosis. Genes encoding for the type II secretion systems required for intracellular growth is required for full …

Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

January 2, 2020November 3, 2017 by Sagar Aryal

Virulence factors of Streptococcus pneumoniae Polysaccharide capsule The capsule is antiphagocytic, inhibiting complement deposition and phagocytosis. 2. Cell wall associated polymers and proteins Teichoic acid – binds to epithelial cells and activates alternative complement pathway Protein adhesion – binds to epithelial cells Peptidogylcan – activates alternative complement pathway Phosphorylcholine – mediates invasion of host cell F protein – mediates attachment …

Virulence factors, Pathogenesis and Clinical manifestations of Listeria monocytogenes

January 8, 2020October 26, 2017 by Sagar Aryal

Virulence factors of Listeria monocytogenes 1. Adhesion proteins (Ami, Fbp A, flagellin) Mediate bacterial binding to host cell that contribute to virulence. 2. Listeriolysin O A hemolytic and cytotoxic toxin that allows for survival within phagocytes. 3. Internalin Cell surface protein that induces phagocytosis. 4. Act A Induces actin polymerization on the surface of host cells, producing cellular extensions and facilitating …

Pathogenesis and Clinical manifestation of Mycobacterium tuberculosis

January 15, 2020October 19, 2017 by Sagar Aryal

Virulence factors of Mycobacterium tuberculosis A. Mycolic acid and Lipoarabinomannan (LAM) Waxy layer that protects the bacteria from many host factors and also to many antibiotics including beta lactamases. Muramyl dipeptide (from peptidoglycan) complexed with mycolic acids can cause granuloma formation, phospholipids induce caseous necrosis. LAM is structurally and functionally related to the O antigenic lipopolysaccharides of other bacteria. Biological …

Pathogenesis and Clinical Manifestation of Neisseria gonorrhoeae

January 11, 2020October 17, 2017 by Sagar Aryal

Virulence factors or antigenic structures of Neisseria gonorrhoeae A. Pili Pili are the hair like appendages that extend up to several micrometers from the gonococcal surface. It mediates the exchange of genetic material between strains and attachment to human mucosal cell surface, invasion of host cells, and survival through the inhibition of phagocytosis. Two types: types T1-T2 virulent and T3-T5 …

Clinical manifestation and Pathogenicity of Bacillus cereus

January 2, 2020October 15, 2017 by Sagar Aryal

Clinical manifestation of Bacillus cereus A. Food poisoning Two forms of food poisoning: vomiting disease (emetic form) and diarrheal disease (diarrheal form). Emetic form The emetic form of disease results from the consumption of contaminated rice. Most bacteria are killed during the initial cooking of the rice, but the heat-resistant spores survive. If the cooked rice is not refrigerated, the …

Virulence factors and Clinical manifestation of Staphylococcus aureus

June 28, 2020October 14, 2017 by Sagar Aryal

Virulence factors of Staphylococcus aureus A. Cell wall components Polysaccharide Capsule: inhibits phagocytosis Peptidoglycan: activates complement, IL-1, chemotactic to PMNs Teichoic acid: species specific, mediate binding to fibronectin Protein A: It binds to the Fc region of IgG and complement ,exerting an anti-opsonin effect. Fibronectin binding protein(FnBP): promote binding to ,mucosal cells and tissue matrices. Clumping factor: FnBP enhances clumping …

Clinical manifestation and Pathogenesis of Streptococcus pyogenes

January 10, 2020October 11, 2017 by Sagar Aryal

Clinical manifestation and Pathogenesis of Streptococcus pyogenes Virulence factors of Streptococcus pyogenes A. Antigenic structure M protein: rod like coiled structure with two major structural classes; Class I and Class II ;major virulence factor;resist phagocytosis and intracellular killing by polymorphonuclear leukocytes in the absence of antibodies. B. Toxins and enzymes Streptokinase It is also called as fibrinolysin. It transforms the …