10. What makes some bacterial cells pathogenic but not probiotic organisms that live in our gastrointestinal tract?

10.) What makes some bacterial cells pathogenic but not probiotic organisms that live in our gastrointestinal tract?

A.)

[What makes bacteria pathogenic?]

Pathogenicity represents a form of specialization that enables certain microorganisms to replicate within specific animals and damage host cells. The outcome is as dependent on the host as it is upon the properties of the pathogen. The ability of the human body to prevent most of the bacteria it encounters from doing harm is the result of an evolutionary course that has produced a complex set of overlapping defenses. The non-specific defenses include antibacterial substances such as complement, phagocytic cells, and the washing action of fluids such as saliva and urine. The specific defenses are cells producing antibodies upon stimulation, and cytotoxic cells. The non-specific defenses are the host's only defenses in the critical early period when infection develops, thus it is not surprising that many of the characteristics allowing certain types of bacteria to cause infection are characteristics that allow them to evade the non-specific defenses of the body. They include factors that help the bacteria to adhere to and invade cells and tissues. Some bacteria are well equipped to evade the body's defense mechanisms, and some produce toxins that cause symptoms and disease. The production of virulence factors is finely tuned and regulated.

Probiotics

Probiotics are a concoction of microorganisms that also includes bacteria. These probiotics contain live bacteria of beneficial nature. They play a vital role in maintaining gut health. They also have other advantages, such as improving immunity, reducing weight, aiding in digestion, etc. In general, they take care of gastrointestinal tract disorders.

Probiotics are generally safe for human consumption. Yoghurts are the most common form of probiotic used by humans.

Pathogenic Bacteria

Pathogens are usually disease-causing microorganisms. Likewise, disease-causing harmful bacteria are termed pathogenic bacteria. These pathogenic bacteria attack their host and damage them directly or indirectly. Thus, they cause infections that need to be treated.

Some pathogenic bacteria can invade the skin surface and mucus, while other advanced ones invade our internal bloodstream.

Differences between Probiotic and Pathogenic Bacteria

Probiotics	Pathogenic Bacteria
They are beneficial.	These are harmful disease-causing bacteria.
They do not have any virulence.	They are virulent enough to induce toxicity.
They do not produce colonies.	Pathogenic bacteria are known to produce colonies.
They maintain gut health and take care of the gastrointestinal tract.	They cause severe illness which needs prevention and treatment.
Examples – Lactobacillus sps, Saccharomyces boulardii, Bifidobacterium, etc.	Examples – Mycobacterium tuberculosis, Clostridium, Streptococcus pneumoniae, etc.