Pathogenic & Non pathogenic organisms.pptx

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1. P athogenic & Non pathogenic organisms MARY MATHA COLLEGE OF ARTS & SCIENCES Department of Biotechnology By Dr.S.HIMALINI

2. The Pathogenic bacteria is a biological agent that causes disease to the host . They are often referred to as Infectious agents, so they have a capability to invade inside the host cells. Non- pathogenic bacteria inhabit the gut environment. These microbes are referred to as gut flora, they live outside the body cells.

3. Basic structure of bacteria and their associated environmental reservoirs. 

4. I ntroduction Our bodies are host to many microbes, most of which do not cause disease and many of which are beneficial. Occasionally , however, microbes do cause infection and disease. Pathogens such as  Staphlococcus ,  Vibrio cholera  and  Mycobacterium tuberculosis  differ from normal non-pathogenic microbes in that they cause damage to the host.  

5. This damage allows the pathogen to colonize novel sites, antagonizes the host immune response, and facilitates spread of the pathogen. The pathogens inflict damage on their hosts by secreting toxins that act on host cell membranes or translocate across the cell membrane and usurp normal cellular functions. 

6. The pathogenic bacteria growing in tissues may form heterogeneous communities with bacteria expressing different protein profiles depending on their micro-environment . 

7. Pathogen emergence is a dynamic, complex, and multifactorial phenomenon that involves an interplay of various genetic adaptations and ecological drivers. Microorganisms are built to evolve. Bacteria in particular, such as the agents of cholera and the plague, possess incredibly sophisticated mechanisms that render them capable of acquiring pieces of DNA from the environment or accumulating mutations that allow them to adapt to new environments in a way that multicellular organisms such as humans never could. They are essentially “evolution machines .”

8. Pathogenicity :   The ability of micro-organisms to induce disease, which may be assessed by disease- carriage ratios • Virulence : The severity of the disease induced by micro-organisms. In epidemiological studies virulence may be assessed by mortality or morbidity rates and the degree of communicability Reservoir : The place where the organism maintains its presence, metabolizes, and replicates • Source: The place from which the infectious agent passes to the host. In some cases the reservoir and the source are the same, but not always • Infection : A microbiologically proven clinical diagnosis of inflammation.

9. Carriage : Permanent (minimally 1 week) presence of the same strain in any concentration in body sites normally not sterile ( oropharynx , external nares , gut, vagina, skin) • Abnormal carrier state: The abnormal carrier state exists when the isolated micro-organisms is not a constituent of normal flora (i.e., enterobacterial or pseudomonal strains) Colonization : The presence of micro-organisms in an internal organ that is normally sterile (e.g., lower airways, bladder). The diagnostic sample yields less than a predetermined level of cfu /ml of diagnostic sample.

10.   Factors that Determine  the Pathogenicity Host susceptibility Presence of mechanisms to fight with the infection by the host immune system • p athogenic mechanisms of bacteria Bacterial infectivity, host resistance, virulence genes, host- mediated pathogenesis (Gram-negative bacterial sepsis, tuberculosis, and tuberculoid leprosy) and intracellular growth • Specific virulence factors Adherence and colonization factors, invasion factors, presence of a capsule and other surface components, endotoxins , exotoxins , and siderophores

11. Humans can only pass genes vertically through generations, that is, from parents to offspring . In contrast, bacteria can pass on genes vertically and also horizontally, trading chunks of genetic information among one another in ways that can accelerate evolution. Through this type of gene transfer, some virulence traits emerge when a cell acquires genetic material from other microorganisms or from its surrounding environment.

12. Pathogenicity islands   are large clusters of genes that are confined to pathogenic strains within a species and typically encode important genes that are critical for host colonization. For instance, the pandemic strains of  V. cholerae  harbor several major pathogenicity islands; one encodes an essential intestinal colonization factor called  toxin- coregulated pilus .  Bacteriophages  are viruses that can infect bacteria and in certain cases can integrate within the genome and confer new traits to the host cell. Bacteriophages are a major vehicle for the acquisition of bacterial toxins in several pathogens.

13. Non-Pathogenic Microorganisms They are incapable of causing disease. i.e., harmless to other organisms • They mostly live in the environment as saprophytes. Some of them are autotrophs . Around 99% of bacteria are nonpathogenic. They are useful to man as they are involved in manufacturing foods such as butter, cheese , alcohol, lactic acid, Probiotics and fermented products, antibiotic, gradual decomposition of organic matter (dead animals, plants and their wastes) on or in the soil. • bio fertilizers etc .

14. Some non-pathogenic bacteria live on the surface of animals as normal flora. They are commensals . • But, these bacteria can become opportunistic pathogens when they invade the tissues. For example, E. coli are non-pathogenic bacteria that live in the gastrointestinal tract and can trigger an immune response under certain circumstances.

15. Activities of Non-Pathogenic  Microorganisms

16. Petrification Petrification is the decomposition of proteins (animal matter) under anaerobic conditions and of carbohydrates (vegetable derivatives starch or sugar). These two processes transform organic matter into useful plant foods. When dead animals and plants are buried in the ground, the soil micro-flora and the intestinal micro-flora of dead animal enter into the tissue of the animal or plant. Decay Decay is the term used generally to denote the gradual decomposition of organic matter (dead animals, plants and their wastes) on or in the soil.

17. Because of their lipolytic , proteolytic and saccharolytic activities. The microbes break fats, proteins and sugars, respectively. The gases (carbon dioxide, ammonia, hydrogen sulphate etc.) liberated and water formed enter in the air, soil. Besides , nitrogen, phosphorus, sulfur, produced from dead animal body combine with water and become soluble and suitable as food for plants. Ultimately , the dead animal disappears. Later, the living animals and men use the plants as food. In this way, the recycle of the elements is continued.

18. Thus, the life would be impossible on earth without microbial activity and the microbes are useful or essential for animal or human life . The coli-bacillus and other species of microbes in the healthy human intestine produce vitamins (B 1 , B 2 , B 12 , K) essential for the human body.

19. Acidophilic microbes Acidophilic microbes are beneficial to the human body as they interfere with the development of pathogenic bacteria which enter the intestine along with food or drink . It is well known that human beings cannot digest directly the cellulose of the plants and utilise it for their nutrition; but the stomach micro-flora of ruminants (cattle, sheep, goats) can only digest it anaerobically and convert into easily digestible end products like glucose, amino acids, volatile fatty acids, which are excreted through milk or incorporated in animal tissue or muscle.

20. ii. Microorganism in Food Moist-less acidic foods (milk, cooked cereals, custard, soup) are suitable media for the growth of saprophytic and pathogenic microorganism at warm room temperature and thus we consume large number of saprophytic microorganisms along with the foods every day with no harmful effects.

21. Fermentation Under anaerobic conditions, the microorganisms (bacteria, yeasts, moulds) decompose, by their saccharolytic activities, the carbohydrates (sugars) into different kinds of acids, such as lactic acid, alcohol, and gases like carbon dioxide . One of the most familiar type of fermentation is the production of alcohol by yeast from the sugar of fruit juices as in wine manufacture.