Are Bacteria Pathogens? 9 Facts You should Know


In this article we will discuss about “are bacteria pathogens” with 9 facts in detail.

The word pathogenic bacteria means it is an organism in which, under favorable conditions, it can directly attack to get nutrients for their growth which causes damage to a host. Some pathogenic bacteria act as a facultative or some as an obligate.

Now take a look at 9 facts about are bacteria pathogens in detail

Are all bacteria pathogens?

All bacteria are not pathogenic because some bacteria do not cause any symptoms of infection or attack a host for their survival such kinds of bacteria are not pathogenic and are referred to as non-pathogenic bacteria.

Here are some examples of pathogenic and non-pathogenic bacteria: Pathogenic Bacteria like Mycobacterium tuberculosis, Staphylococcus Aureus, Pseudomonas aeruginosa, Burkholderia cenocepacia, mycobacterium avium, Yersinia pestis and Non-Pathogenic Bacteria include Acetobacter, Lactobacillus casei, Listeria innocua, Micrococcus diversus, Bacillus licheniformis, Arthrobacter globiformis, Methylobacterium

What type of bacteria is a pathogen?

There are two types of bacteria, Gram-positive bacteria, and Gram-negative bacteria. There are some bacteria names like pseudomonas, acetobacter, and E.coli that develop resistance to antibiotics and stay survive.

Here are some examples of different type of bacteria which is pathogenic and harmful:

Vibrio Cholerae is a facultative, anaerobe, Gram-negative bacteria which secret cholera toxin as a toxic agent. Salmonella Typhi is a gram-negative, rod-shaped bacteria that normally grow in the intestine, spleen, bone marrow, and liver. Streptococcus pyogenes is a nonmotile, pathogenic, aerotolerant, gram-positive bacteria that contain a virulence factor on its surface for pathogenicity. Enteritis Salmonella is a facultatively anaerobic, flagellate, gram-negative bacteria that cause pathogenic infections and is harmful.

Some other groups of intracellular bacteria that are pathogenic like,

Yersinia pestis is a coccobacillus, nonmotile and gram-negative bacteria. The other closely related species are Yersinia enterocolitica and Yersinia pseudotuberculosis. Legionella pneumophila is a gram-negative, aerobic, and flagellated coccobacillus bacteria. It produces some enzymes like catalase, beta-lactamase, and oxidase. Mycobacterium tuberculosis is a gram-positive pathogenic bacteria belonging to the mycobacteriaceae family.it acts as antibiotic resistance in nature. Brucella melitensis is a coccobacillus, gram-negative bacteria belonging to the Brucellaceae family. Nocardia act as a intracellular bacteria which is a rod-shaped, gram-positive bacteria. Some species of this bacteria are pathogenic and are capable to infect both humans and animals and other some species are harmless.

The other some species include Neisseria meningiidis is a diplococcus, gram-negative bacteria. The outer membrane of this bacteria contain Lipooligosaccharide and some other virulence factors like polysaccharide capsules that is act as an endotoxin cause the destruction of red blood cells Listeria monocytogenes is an anaerobic facultative pathogenic bacteria that act as a most virulent foodborne pathogen. It can able to survive in both presence and absence of oxygen. Francisella tularensis is an aerobic, Facultative intracellular, coccobacillus, non-spore-forming, gram-negative bacterium.it can survive in low temperatures with require cysteine for growth and it can capable to infect most cell types.

Are bacteria and pathogens the same?

Bacteria and pathogens are not the same because the word pathogen means it is an all small creature, one minor unit which all are in different forms can infect or be harmful, while the bacteria is exist as in structurally small, in pair, chain or in clusters form.

It is a member of a single-celled group that proliferates by itself, has its metabolism, and belongs to the kingdom Eubacteria. Some bacteria are pathogens but some are not.Thus, Bacteria and pathogens are not the same.

Are most bacteria pathogens?

Most bacteria are not pathogens. In the earth ecosystem, there are five nonillion bacteria in which less than 1% of all bacteria are considered dangerous or harmful to other living beings. The number of pathogenic species in humans is estimated to be fewer than a hundred. The proportion of bacteria that can harm through toxicity and infections may not account for even 0.1% of all bacteria types.

The number of pathogenic bacteria is within that small or less percentage of harmful ones and very very limited because most bacteria are beneficial to us, non-pathogenic bacteria possess many beneficial properties related to health and other industrial use applications. Several thousand species of bacteria are part of the gut flora present in our digestive tracts

Are bacteria complex pathogens?

Not all bacteria are complex pathogens.The complexity of pathogenic bacteria depends on their properties and pathogenicity. Some bacteria are moderately pathogenic while some are highly pathogenic. But, bacteria are more complex and bigger than viruses because bacteria can reproduce and live anywhere on their own.

A successful complex pathogen is use some host resource and can reproduce itself.it can colonize the host and spread and exit to a new host. These pathogenic bacteria are most of heterotrophic,act as a consumer to depend on other microorganisms for their nutrition, growth, and survival, they are also capable to release or emit some toxic agents which it can affect other individuals in nature.The complex pathogen can avoid the host’s adaptive and innate immune responses. It can carry some specialized virulence genes, which make one complex or cluster together and make one pathogenicity islands. These kinds of complex pathogens are termed opportunistic pathogens, Obligate pathogens, and facultative pathogens.

Are all enteric bacteria pathogens?

Not all enteric bacteria are pathogens.The word “enteric bacteria” is come from a greek word that means intestine. It is a microbe that can affect the intestine. Enteric pathogens are one large family of gram-negative bacteria.

Here some examples include,Shigella, Citrobacter, Klebsiella, Enterobacter, Serratia, Proteus, and many moreThe bacteria Escherichia coli is a one enteric bacteria and a very common normal part of every mammal’s intestinal flora. Some strain of this bacteria is harmless while some others are toxic. Vibrio cholera is moderate to severe toxic. Campylobacter jejuni is also a very common enteric pathogen bacteria.

How many bacteria are pathogens?

All bacteria do not act as a pathogen in this world. A very small list of pathogenic bacteria cause infections in which some bacteria are harmful or some are useful and healthy for the environment and human health. Only about 5% of bacterial species are identified as pathogenic.

There are around 1400 to 1500 species including protozoa, fungi, bacteria, and viruses of which less than 1% are harmful or infectious. According to the bacterial size, around 0.14-0.15 and 600 to 700micrometer in length are beneficial and harmless to humans.

How to know if a bacteria is pathogenic?

Pathogenic bacteria differ from non-pathogenic because pathogenic bacteria secret some toxins and inflict damage on the host and antagonize the immune response of the host. It acts on the cell membrane of the host and causes to damage irregular cell functions. It also depend on other as a consumer for their growth nutrition, and survival.

To ensure the type of pathogenicity, Here are some characteristics of pathogenic bacteria: Those bacteria produce some toxic agents like exfoliatin, and enterotoxin and possess some enzymes like Dnase which can degrade or denature the nucleic acid-like DNA, and coagulase which has a capacity for blood clots.

Bacteria may have an Antigenic structure that has the ability responses, a capsule that helps to prevent bacterial cells in the process of phagocytosis, and flagella that main function is motility inside the host.Bacteria are resistant to antibiotics which means bacteria have some mechanism by which they can able to survive in the presence of different kinds of AntibioticsHere the example of bacteria that possess such kind of characteristics are pathogens in nature and those bacteria are termed a Pathogenic bacteria: Salmonella, clostridium, mycobacterium, Neisseria, staphylococcus,Cryptococcus, campylobacter, Helicobacter, Borrelia

are bacteria pathogen example
Neisseria gonorrhoea from Wikipedia

Why are not all bacteria pathogens?

All bacteria are not pathogenic. Some particular strain of bacteria can be pathogenic while other is non-pathogenic. The value of non-pathogenic bacteria is higher and more useful compared to that of pathogenic bacteria. Such kinds of nonpathogenic bacteria are present within the human body termed “microbiota” also known as autotrophic or saprophytic.

If the entire world has only a strain of pathogenic bacteria, the human, plants, or other organisms are not able to survive on this planet because due to non-pathogenic bacteria, organisms, plants, and humans on this planet can protect their immunity, digestion, metabolism, and all such kind of activity.Thus the requirement of non-pathogenic bacteria is mandatory for survival and growth.For example, the main activity of this useful bacteria is Decay– organic matter decomposition, putrefaction-Under anaerobic conditions, the decomposition of protein and the other is fermentation– conversion of carbohydrates into different acids. Human beings are not able to digest the cellulose of the plant but due to the presence of microflora of nutrients, it can convert that cellulose into soluble and digestible products like amino acids, glucose, and other volatile fatty acids.

Here some applications of nonpathogenic bacteria are: They can act as Industrial microorganisms, they can act as Nitrogen-fixing microorganisms for symbiotic and nonsymbiotic nitrogen fixation and nitrification, Bioremediation, wastewater treatment methods, biofuel industries, Enzyme production from bacteria used in different kinds of fermented and dye industry, dairy, and food industries, used for different kind of medical and pharmaceutical industries and many more.

Bhairavi Rathord

Hello, I am Bhairavi Rathod, qualified ICAR NET 2021 in Agricultural Biotechnology. My area of specialization is Integrated Biotechnology. I have the experience to teach and write very complex things in a simple way for learners. My LinkedIn profile: https://www.linkedin.com/in/bhairavi-rathod-806993130

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