Help With Microbiology- Exotoxins and Endotoxins

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Specializes in None.

Could someone provide me with a better understanding than what I have on these two topics: exotoxins and endotoxins. The way I am understanding is that exotoxins are inside the pathogenic bacteria, but are released on the outside of the cell? This does not make any sense at all. Does this mean the the toxins are inside the particular bacteria which is transmitted inside the cell and the cell releases the toxic substance to outside of the cell? For endotoxins, I understand it a little better. Clarify if I am not right, the endotoxins are composed of lipids that are "hanging on" to the side of the cell?

Any additional information would be great. Tried Youtube, but did not have many options to clarify. I believe this is a simple understanding, but I tend to make easier things way harder than they really are.

Thanks for any help!

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Specializes in pediatrics, public health.

It's been years since I took micro so I can't answer out of my own knowledge base, but here's what looks to be a good comparison: BSCI 424 Pathogenic Microbiology -- Exotoxin vs. Endotoxin

Hope that helps! Good luck!

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Specializes in None.
It's been years since I took micro so I can't answer out of my own knowledge base, but here's what looks to be a good comparison: BSCI 424 Pathogenic Microbiology -- Exotoxin vs. Endotoxin

Hope that helps! Good luck!

Thanks for trying to help! I looked at that earlier, but for some reason i'm still having a hard time understanding the basic idea of it.

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exotoxins work on the outside, endotoxins work on the inside

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Endotoxins are an integral part of the Gram negative membrane and are only released by lysis. they are not present in Gram positive bacteria since gram positive do not have an outer membrane. The presence of Lipid A is indicative of endotoxins.

Exotoxins exist within the cytoplasm of both gram positive and gram negative bacteria and can be excreted into the cell - thus it does not take the death of the bacteria for their release.. but can be released by lysis as well.

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Specializes in pediatrics, public health.
The way I am understanding is that exotoxins are inside the pathogenic bacteria, but are released on the outside of the cell? This does not make any sense at all. Does this mean the the toxins are inside the particular bacteria which is transmitted inside the cell and the cell releases the toxic substance to outside of the cell?

The cell secretes the exotoxin into its environment. It's manufactured inside the pathogenic bacteria, which then releases it outside the cell. I'm not sure why this doesn't make sense? Cells manufacture all sorts of substances which they then secrete to the environment. In the case of pathogenic bacteria, those secretions are toxic.

For endotoxins, I understand it a little better. Clarify if I am not right, the endotoxins are composed of lipids that are "hanging on" to the side of the cell?

Endotoxins are lipopolysaccharides that are an integral part of the cell wall. They aren't just "hanging on" to the side of the cell, they are part of the cell wall.

Hopefully that's more helpful than my last post. :) That's all I've got. Good luck!

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Specializes in None.

Thanks noahsmama, that helped! :)

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Specializes in Hospice, Palliative Care.

Good day:

Here's a chart I put together when I was doing a comparison between the two if it helps you. The release method is listed in the chart.

[TABLE]

[TR]

[TD]

[/TD]

[TD]Endotoxin

[/TD]

[TD]Exotoxin

[/TD]

[/TR]

[TR]

[TD]

[/TD]

[TD]

[/TD]

[TD]

[/TD]

[/TR]

[TR]

[TD]Gram Positive

[/TD]

[TD]No

[/TD]

[TD]Yes

[/TD]

[/TR]

[TR]

[TD]Gram Negative

[/TD]

[TD]Yes

[/TD]

[TD]Yes

[/TD]

[/TR]

[TR]

[TD]Location

[/TD]

[TD]Outer membrane of Gram- negative cell wall

[/TD]

[TD]Synthesized in cytoplasm; may or may not be secreted; generally carried on plasmids.

[/TD]

[/TR]

[TR]

[TD]Composition

[/TD]

[TD]Lipopolysaccharide (Lipid A component)

[/TD]

[TD]Protein

[/TD]

[/TR]

[TR]

[TD]Heat stability

[/TD]

[TD]Heat stable

[/TD]

[TD]Inactivated by heat except for Staphylococcus aureus

[/TD]

[/TR]

[TR]

[TD]Release method

[/TD]

[TD]Cell lysis or bacteria death

[/TD]

[TD]Secretion or bacterial cell lysis

[/TD]

[/TR]

[TR]

[TD]Antigenicity

[/TD]

[TD]Poorly antigenic

[/TD]

[TD]Induces antibodies called antitoxins

[/TD]

[/TR]

[TR]

[TD]Symptoms

[/TD]

[TD]Systemic response, fever, decrease in BP, DIC (Endotoxic Shock)

[/TD]

[TD]Distinct toxic mechanism (Cardiotoxin would affect heart)

[/TD]

[/TR]

[TR]

[TD]Representative Diseases

[/TD]

[TD]Typhoid fever

Urinary tract infections

Meningococcal meningitis

[/TD]

[TD]Gas gangrene

Tetorifice

Botulism

Diptheria

Scarlet fever

[/TD]

[/TR]

[TR]

[TD]Potency

[/TD]

[TD]Small amount localized lead to an appropriate response but systemic distribution can be deadly

[/TD]

[TD]Among most lethal substances known

[/TD]

[/TR]

[TR]

[TD]Producers

[/TD]

[TD]Salmonealla Typhi (thyphoid feaver)

Neisseria meningitides (meningitis)

Escherichia coli

[/TD]

[TD]Straphylococcus

Streptococcus pyogenes

Corynebacterium diptheriae

Straphlococcus aureus

Clostridium perfringens

Clostridium tetani

Vibrio cholera

Escherichia coli

Basillius antrhacis

Clostridium difficile

[/TD]

[/TR]

[TR]

[TD]Vaccine available

[/TD]

[TD]No

[/TD]

[TD]Yes as a toxoid

[/TD]

[/TR]

[/TABLE]

Thank you.

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Specializes in None.
Good day:

Here's a chart I put together when I was doing a comparison between the two if it helps you. The release method is listed in the chart.

[TABLE]

[TR]

[TD][/TD]

[TD]Endotoxin[/TD]

[TD]Exotoxin[/TD]

[/TR]

[TR]

[TD][/TD]

[TD][/TD]

[TD][/TD]

[/TR]

[TR]

[TD]Gram Positive[/TD]

[TD]No[/TD]

[TD]Yes[/TD]

[/TR]

[TR]

[TD]Gram Negative[/TD]

[TD]Yes[/TD]

[TD]Yes[/TD]

[/TR]

[TR]

[TD]Location[/TD]

[TD]Outer membrane of Gram- negative cell wall[/TD]

[TD]Synthesized in cytoplasm; may or may not be secreted; generally carried on plasmids.[/TD]

[/TR]

[TR]

[TD]Composition[/TD]

[TD]Lipopolysaccharide (Lipid A component)[/TD]

[TD]Protein[/TD]

[/TR]

[TR]

[TD]Heat stability[/TD]

[TD]Heat stable[/TD]

[TD]Inactivated by heat except for Staphylococcus aureus[/TD]

[/TR]

[TR]

[TD]Release method[/TD]

[TD]Cell lysis or bacteria death[/TD]

[TD]Secretion or bacterial cell lysis[/TD]

[/TR]

[TR]

[TD]Antigenicity[/TD]

[TD]Poorly antigenic[/TD]

[TD]Induces antibodies called antitoxins[/TD]

[/TR]

[TR]

[TD]Symptoms[/TD]

[TD]Systemic response, fever, decrease in BP, DIC (Endotoxic Shock)[/TD]

[TD]Distinct toxic mechanism (Cardiotoxin would affect heart)[/TD]

[/TR]

[TR]

[TD]Representative Diseases[/TD]

[TD]Typhoid fever

Urinary tract infections

Meningococcal meningitis[/TD]

[TD]Gas gangrene

Tetorifice

Botulism

Diptheria

Scarlet fever[/TD]

[/TR]

[TR]

[TD]Potency[/TD]

[TD]Small amount localized lead to an appropriate response but systemic distribution can be deadly[/TD]

[TD]Among most lethal substances known[/TD]

[/TR]

[TR]

[TD]Producers[/TD]

[TD]Salmonealla Typhi (thyphoid feaver)

Neisseria meningitides (meningitis)

Escherichia coli[/TD]

[TD]Straphylococcus

Streptococcus pyogenes

Corynebacterium diptheriae

Straphlococcus aureus

Clostridium perfringens

Clostridium tetani

Vibrio cholera

Escherichia coli

Basillius antrhacis

Clostridium difficile[/TD]

[/TR]

[TR]

[TD]Vaccine available[/TD]

[TD]No[/TD]

[TD]Yes as a toxoid[/TD]

[/TR]

[/TABLE]

Thank you.

Thank you! Oh, and I love your avatar!:)

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Specializes in Critical Care, Education.

Also - very interesting Gram Neg issue.. . patients tend to get 'sicker' for a while after you start the antibiotic because even more toxin is released as the bacteria are destroyed. Potential for septic shock is higher with Gram neg.

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