BACTERIAL VIRULENCE FACTORS

Bacterial Virulence Factors



Bacterial Virulence Factors

Introduction

At starting of twentieth century, foremost causes of death were infection diseases, which are caused by microorganisms called pathogen. The pathogen has been implicated in numerous situations and outbreaks over world and advised as foremost that possibly intimidate human live. It causes some diseases, for instance: verocytotoxin (VTEC), making E. coli which causes heamorrhagic colitis (HC), haemolytic-ureamic syndrome (HUS) and rarely gentle non-bloody asymptomatic. In supplement Salmonella, Campylobacter are furthermore advised as vital because of increasing incidence and severity of its complications. It has been approximated that roughly of nourishment poisoning affiliated with those pathogen in UK incidence of one in 56, in which cost UK, finances more than 1£ billion annually (www.ncbi.nlm.nih.gov).

Discussion

Invasion Factors

Mechanisms that endow the bacterium to invade eukaryotic units help application at mucosal surfaces. Some of these invasive bacteria (such as Rickettsia and Chlamydia species) are obligate intracellular pathogens, but most are facultative intracellular pathogens (www.ncbi.nlm.nih.gov). The specific bacterial exterior factors that mediate attack are not renowned in most examples, and often, multiple gene goods are involved. Some Shigella attack factors are encoded on the 140 mega Dalton plasmid, which, when conjugated into E. coli, devotes these non-invasive bacteria capability to invade cells. Other invasion genes have furthermore lately been recognised in Salmonella and Yersinia pseudotuberculosis. The means of attack of Rickettsia, and Chlamydia species are not well known.

 

Capsules and Other Surface Components

Bacteria have developed many functional and metabolic virulence factors that enhance their survival rate in host. Capsule formation has long been identified as the shielding means for bacteria. (www.ncbi.nlm.nih.gov) Encapsulated strains of numerous bacteria (e.g., pneumococci) are more virulent and more resistant to phagocytosis and intracellular murdering than are non-encapsulated strains. Organisms that cause bacteremia (e.g., Pseudomonas) are less perceptive than numerous other bacteria to murdering by new human serum encompassing support constituents, and accordingly are called serum resistant. Serum opposition may be associated to allowance and composition of capsular antigens as well as to structure of lipopolysaccharide. The connection between exterior structure and virulence is significant furthermore in Borrelia infections (www.ncbi.nlm.nih.gov).

Some bacteria and parasites have proficiency to endure and reproduce interior phagocytic cells. A classic demonstration is Mycobacterium tuberculosis, whose survival appears to count on structure and composition of its cell surface. The parasite Toxoplasma gondii has amazing proficiency to impede fusion of lysosomes with phagocytic vacuole. The hydrolytic enzymes comprised in lysosomes are incapable, thus, to assist to decimation of parasite (www.ncbi.nlm.nih.gov). The mechanism(s) by which bacteria for example Legionella pneumophila, Brucella abortus, and Listeria monocytogenes stay unharmed interior phagocytes are not understood.

Most bacteria comprise some sort of the polysaccharide level out-of-doors of cell partition or outside membrane. In the general sense, this level is called the capsule (www.textbookofbacteriology.net). A factual capsule is the discrete obvious level of polysaccharides made a down fee out-of-doors cell wall. Some microbiologists address all kinds of exopolysaccharides to be glycocalyx. Capsules, slime levels, and glycocalyx are renowned to mediate specific or non specific adherence of bacteria to specific ...