Aeromonas Hydrophila and Bacillus Subtillis

Hi Yall!
This is going to be a long post and hopefully informative.

3 years ago i lost 2 fish to a wound, it looked a lot like you might think a heater burn looks. We called it "The Mark" because we didnt know what cause it. The 2nd fish that had The Mark was sent to UFL for necropsy. The results were difinitive, Aeromonas Salmonicida.
Once we had a diagnosis, we needed to find a cause, a preventative, and a cure in case we saw it again. Since that time, i have seen Many, Many cases of Aeromonas. The Mark is always the same, every fish, every time. It is not always Salmonicida and this is actually a rare strain to see in discus as it prefers cooler water temperatures and our discus tanks are much warmer than it likes. We do however, see other strains. Veronii being the most common and Hydrophila being common as well.
Aeromonas are gram negative bacteria that inhabit water. They cannot be removed from the water so we have to work to keep numbers low. preventative water changes and healthy foods help prevent infections. Aeromonas are opportunistic bacteria so a healthy fish stays healthy.
Symptoms of Aeromonas infection can range from bloat/dropsy to open sores and wounds. It is very hard to treat and can lead to death in as little as 48 hours.

https://www.microbiologyresearch.org...0?crawler=true


The veterinarian i use at UFL recommended the use of nitrofurazone and aquarium salt for treatment of aeromonas. However, a study done this year has shown that aeromonas is now nearly impossible to treat. Overuse of medications and incorrect dosing of medication is the biggest problem in the hobby today. (i wont go into that today, i have already written about it)

So here are the medications with resistance percentage:
100% Penicillin, Amoxicillin, and Nalidixic acid
98% ampicillin
80% quinolones
58% tetracycline and nitrofurans*
25% ciprofloxacin (an earlier study had Cipro at 64%, not sure about the discrepency)
5% aminoglycocides (cant find this available for fish)

https://sfamjournals.onlinelibrary.w...h1KLG9YZQGBbRo


With these medications no longer effective i started looking at immune system boosting. With the help of my veterinarian i have added several vitamins to my beef heart recipe and made it more profilactic, luckily the fish love it.

In further research, i ran across many articles that mention Bacillus Subtillis. It is in the same family as Cereus but is not toxic. On the contrary, research has shown that B. Subtillis actually prevents the damage done by Aeromonas. I was surprised but the more i pulled up they all said the same.

Aeromonas causes damage to the lining and villi of the intestine. B. Subtillis actually prevents this from happening.

In a Study done in 2019, researchers used 4 control groups.
group 1- fish food with no additives
group 2 fed artimis with no additives
group 3 fed artimis infused with B. Subtillis
Positive group was the 4th

For growth and development all groups were the same. For reproduction, group 1 & 2 were the same but group 3 had higher fertility and higher fry survival rates than groups 1 & 2.
Once the feeding portion of the research was concluded, all fish were injected with Aeromonas Hydrophila. from the 3 groups group 3 and the positive group (treated with oxytetracycline) had the highest survivability rates.
at 68% and 62% respectively.

https://link.springer.com/article/10...602-018-9453-4



After doing a bit of a search on google i found that B Subtillis is very commonly used as an profylactic in humans.
This is now something i will be adding to my beefheart mix to help prevent aeromonas infections.

The following article was not used in this posting, however it is extrememly informative about the effects of aeromonas and what B. Subtillis does in the intestine.

https://www.nature.com/articles/s41598-017-01336-9




Tammy

PS please excuse my translation to laymans terms, i understand quite well what im reading but trying to relay it is difficult lol

Excellent article Tammy. Worthy of additional research for my own curiosity...

Quote:

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Originally Posted by jeep

Excellent article Tammy. Worthy of additional research for my own curiosity...

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That is why i linked the 2nd article. It goes into more detail about it with graphs and such.

Tammy

Great information Tammy and thanks for posting it.

Jason Oneppo of San Francisco Bay Brine Shrimp is speaking at the Minnesota Aquarium Society meeting this Thursday. As the R&D Manager for SFBB, he'd be the perfect person to ask about B. subtilis enrichment of nauplii.

Quote:

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Originally Posted by Willie

Jason Oneppo of San Francisco Bay Brine Shrimp is speaking at the Minnesota Aquarium Society meeting this Thursday. As the R&D Manager for SFBB, he'd be the perfect person to ask about B. subtilis enrichment of nauplii.

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I am signed up for it. My question atm is about adding it to beef heart. I am concerned about it just going out in the water rather than being consumed.


Tammy

Thank you for the article and even more for putting it in laymen’s terms :). I was lost on the title of the next article :).

Here's a photo of the issue Tammy is referring to in case some have never seen it. It's easy to see why people automatically assume heater burn...

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Photos of aeromonas bacteria from fellow discus hobbyists on SD Facebook page.

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