08-20-2013, 11:53 PM
Bacteria that can cause disease in humans must have a certain characteristic as it interacts with its living host, whether plant, insect, or animal. This type of pathogenicity of microbes is expressed by means of their virulence and its degree of pathogenicity is determined by its structural, biochemical, or genetic features.
The host, the pathogen involved, and the disease probability are dependent on both resistance of the former and the virulence of the pathogen as it combats with the host’s defense systems. For it to prove its pathogenicity, it must follow entrance, adherence, and cause damage to the host.
There are two specific mechanisms involved in bacterial pathogenicity, these are:
1. Invasiveness – ability to access or penetrate body tissues. Associated with it are colonization which consists of adherence and its initial multiplication, production of invasins by extracellular substances, and the bypassing of the hosts defenses. In simpler terms, it is the tendency of the pathogen to spread into healthy tissue.
2. Toxigenesis – ability to generate toxins. Both endotoxins and exotoxins are produced in this manner. Endotoxins are cell-related substances, where they are commonly located at the outer membrane of certain gram-negative bacteria. Exotoxins on the other hand are being released from the bacterial cell itself and act on its surrounding tissue areas. When such toxins are produced, bacteria then act as “poison” since they cause cytotoxic effects to tissues. Toxins spread by invading lymph and blood vessels.
Some other pathogenic diseases and the bacteria responsible are as follows:
• Lyme Disease – Borrelia burgdorferi
• Whooping Cough – Bordetella pertussis
• Acute Enteritis – Campylobacter jejuni
• Tetanus – Clostridium tetani
• Diphtheria – Corynebacterium diphtheria
• Peptic Ulcer – Helicobacter pylori
• Legionnaire’s Disease – Legionella pneumophilia
• Leptospirosis – Leptospira interrogans
• Leprosy – Mycobacterium leprae
• Tuberculosis – Mycobacterium tuberculosis
• Gonorrhea – Neisseria gonorrhoeae
• Shigellosis – Shigella sonnei
• Syphilis – Treponema pallidum
The host, the pathogen involved, and the disease probability are dependent on both resistance of the former and the virulence of the pathogen as it combats with the host’s defense systems. For it to prove its pathogenicity, it must follow entrance, adherence, and cause damage to the host.
There are two specific mechanisms involved in bacterial pathogenicity, these are:
1. Invasiveness – ability to access or penetrate body tissues. Associated with it are colonization which consists of adherence and its initial multiplication, production of invasins by extracellular substances, and the bypassing of the hosts defenses. In simpler terms, it is the tendency of the pathogen to spread into healthy tissue.
2. Toxigenesis – ability to generate toxins. Both endotoxins and exotoxins are produced in this manner. Endotoxins are cell-related substances, where they are commonly located at the outer membrane of certain gram-negative bacteria. Exotoxins on the other hand are being released from the bacterial cell itself and act on its surrounding tissue areas. When such toxins are produced, bacteria then act as “poison” since they cause cytotoxic effects to tissues. Toxins spread by invading lymph and blood vessels.
Some other pathogenic diseases and the bacteria responsible are as follows:
• Lyme Disease – Borrelia burgdorferi
• Whooping Cough – Bordetella pertussis
• Acute Enteritis – Campylobacter jejuni
• Tetanus – Clostridium tetani
• Diphtheria – Corynebacterium diphtheria
• Peptic Ulcer – Helicobacter pylori
• Legionnaire’s Disease – Legionella pneumophilia
• Leptospirosis – Leptospira interrogans
• Leprosy – Mycobacterium leprae
• Tuberculosis – Mycobacterium tuberculosis
• Gonorrhea – Neisseria gonorrhoeae
• Shigellosis – Shigella sonnei
• Syphilis – Treponema pallidum
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