Aeromonas (disturbing Photos) very long read

Hi everyone!

The genus Aeromonas includes 14 strains of bacteria. Of these 14 at least 5 are commonly seen in the aquaria. There are other proposed strains as well but for this topic I will only refer to these 5 strains. Aeromonas are gram negative motile rod shaped anaerobic bacteria. Aeromonas are carried in the gut of animals and fish.
Of these strains some are mesophilic (warm environment) and some are psychrophilic (cooler environment) (Janda 2010). Do not be tricked into thinking that because these bacteria do better in warmer or colder temperatures, they can and do live in both.

Aeromonas veronii has been found as a cause of fish die offs in many fish farms world wide. The virulence of this bacteria is devastating.(N. Sundar 2019)

Aeromonas hydrophila Is another that has been found in the hobby. I was trying to help someone with Aeromonas but within 5 days it has completely wiped out her aquarium. she took 2 to a veterinarian and it was determined to be hydrophila. This happened in Australia.

Aeromonas salmonicida, although the name implicates salmon, this bacteria is found in many countries and infects many species of fish. (Wiklund 1998)

Aeromonas sobria A fish die off in Switzerland was researched and the cause of these deaths was sobria (Wahli 2005) They presented with lesions on their sides.

Aeromonas caviae was identified from catfish in a farm in Africa. It was not the only aeromonas present in these fish.(Anyanwu 2015)

As mentioned these 5 are not the only Aeromonas, nor are they to be considered better or worse than other strains. All of these are debilitating bacteria if an infection occurs. Without treatment death generally occurs within 48 hours of onset of symptoms. This makes immediate treatment very important.


A few years ago I began a search for the cause of the loss of 1 of my fish. There was a bacteria bloom in my tank and 3 of my discus became sick. They were lethargic and sloughing slime coat. These 3 were placed in QT with aquarium salt. 2 of these fish improved, however 1 of them began to develop a lesion on her side. I began treatment with nitrofurazone. The lesion grew quickly and 1 week after the initial onset she went into organ failure and died.
I spent 9 months after this incident trying to find answers. I combed through the groups and forums looking for others who had seen this. I saw hundreds of fish with the exact same lesion. Only 1 of those fish had survived. During the final months of looking for answers for this, I had an angelfish in a tub we keep outside who showed the same lesion. I immediately euthanized this fish and sent him to UFL for necropsy. While waiting for the results I had someone from the Netherlands contact me and inform me that what i was looking for was most likely an Aeromonas. He was correct. Aeromonas salmonicida was the cause.

Once i knew what i was dealing with I started looking at prevention. Curing an Aeromonas infection is proving extremely difficult. The bacteria have become resistant to most antibiotics that are used. So what can we do? Prevention is key. Keeping a clean aquarium is always a 1st for us. so how did this happen? un-needed medicating. We always deworm our fish when we get them. but we had some thoughts that maybe they needed another deworming. We used a medication that contained flubendazole ( i no longer recommend but not because of this incident). This was a premixed medication with fillers and the dosage was in UK gallons. We asked the seller what the amount translates to and he informed us that it was almost the same. So, we dosed a 265G aquarium with a dosage for a 318G tank. 2 days in to treatment we had a bacteria bloom. The lessons we learned from this were extensive. Flubendazole reduces oxygen in the tank, medications that contain fillers are not ideal for use in an aquarium because the filler could create a medium for bacteria growth. I have never been a person to agree with prophylactic treatments and very seldom recommend meds as a 1st treatment. This was a mistake that i made in deviating from my own rules.

Research has been widely done for both human treatments and aquatic. It has been found that many gut biotica will prevent Aeromonas from causing harm to the host. Aeromonas are opportunistic. Bacillus subtilis being 1 of those. Many foods that have added probiotics contain this particular bacteria.(Kong 2017)
Here I will show you the 3 stages Of Aeromonas that i noted during my research.

Stage 1 is an abscess that shows up in the very beginning.
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The 2nd stage is the rupturing of the abscess.
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The final stage is the intermuscular damage.
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As you can see from the photo, all of these fish followed the same pattern and the lesion on all of them look the same. These lesions are not the only way that Aeromonas bacteria present. They can cause a wide range of symptoms, from Dropsy to fin rot to septicemia to organ failure. This particular lesion is indicative of a flesh eating bacteria, and that is what Aeromonas is. It can cause illness in humans as well as fish. Many of the stomach ailments that affect visitors to third world countries can be attributed to Aeromonas. The biggest problems with Aeromonas is the resistance to common medications and the researchers working hard to find new treatments for this bacteria.
If you need further reading material, or easier reading just send me a message. I have tons of papers on this topic.

Tammy






References:

Anyanwu Madubuike Umunna, Chah Kennedy Foinkfu, Shoyinka Vincent Shodeinde (2015) Evaluation of pathogenicity of motile Aeromonas species in African catfish International Journal of Fisheries and Aquatic Studies s 2015; 2(3): 93-98 retrieved 20 January from https://www.fisheriesjournal.com/vol...Pdf/26.1.1.pdf


Janda JM, Abbott SL. The genus Aeromonas: taxonomy, pathogenicity, and infection. Clin Microbiol Rev. 2010 Jan;23(1):35-73. doi: 10.1128/CMR.00039-09. PMID: 20065325; PMCID: PMC2806660. retrieved 20 January 2023 from https://journals.asm.org/doi/full/10.1128/CMR.00039-09

Kong, W., Huang, C., Tang, Y. et al. Effect of Bacillus subtilis on Aeromonas hydrophila-induced intestinal mucosal barrier function damage and inflammation in grass carp (Ctenopharyngodon idella). Sci Rep 7, 1588 (2017). https://doi.org/10.1038/s41598-017-01336-9 retrieved 20 January 2023 from https://www.nature.com/articles/s41598-017-01336-9

N. Sundar Raj, T. Raja Swaminathan, Arathi Dharmaratnam, S. Arun Raja, D. Ramraj, K.K. Lal,
Aeromonas veronii caused bilateral exophthalmia and mass mortality in cultured Nile tilapia, Oreochromis niloticus (L.) in India,
Aquaculture, Volume 512, 2019, 734278, ISSN 0044-8486, https://doi.org/10.1016/j.aquaculture.2019.734278. retrieved 20 January from: https://www.sciencedirect.com/scienc...44848619300857

Wiklund Tom, Dalsgaard Inger (1998 February 26) Occurrence and significance of atypical Aeromonas salmonicida in non-salmonid and salmonid fish species: a review Diseases Of Aquatic Organisms Vol. 32: 49-69,1 retrieved 20 January 2023 from https://www.int-res.com/abstracts/dao/v32/n1/p49-69/

WAHLI, T. et al. Aeromonas sobria, a causative agent of disease in farmed perch, Perca fluviatilis L. Journal of fish diseases, [s. l.], v. 28, n. 3, p. 141–150, 2005. DOI 10.1111/j.1365-2761.2005.00608.x. Disponível em: https://search-ebscohost-com.proxy1....&site=eds-live. Acesso em: 20 jan. 2023.

Very well written. I know we've talked about this for quite some time and the results of the cases we've dealt with are always the same. This stuff moves quickly and is nearly 100% fatal.

Prevention is the best course of action, meaning a good maintenance routine.

Tammy, Thank you very much for taking the time to share the research you have done here. Well written and photo documented. I stuck the thread to the top of the section and we definitely direct members to it when post come up that may be this dreadful infection.

Al

Thanks, Tammy for that long write up. That's one reason why I come here is to learn more.

I need to add this as it was thoughtless on my part. The fish in these photos do not belong to me nor do the photos. All photos are being used for educational purposes with permission from their respective owners.

Tammy

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Originally Posted by brewmaster15

Tammy, Thank you very much for taking the time to share the research you have done here. Well written and photo documented. I stuck the thread to the top of the section and we definitely direct members to it when post come up that may be this dreadful infection.

Al

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Thanks Al,
There is so much more that could be added but i tried to keep it short and also informative. At this time almost all antibiotics are useless against these bacteria, which is why i was so interested in what was used in the other post. Enrofloxacin seems to have the best success at this time but prevention is best.

Tammy

Excellent and helpful. I have always known that good maintenance is critical but through the years my maintenance game is increasing.

Thank you! Can you clarify whether the probiotic food containing bacillus is recommended or not? Do we want to encourage internal bacteria to keep this other one at bay, or does feeding these foods mask a problem until it’s too late? Sorry for the noob question.

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Originally Posted by bossanova

Thank you! Can you clarify whether the probiotic food containing bacillus is recommended or not? Do we want to encourage internal bacteria to keep this other one at bay, or does feeding these foods mask a problem until it’s too late? Sorry for the noob question.

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Hi!
That is an amazing question. Bacteria, Archaea, protozoa and other microbiotica make up our digestive flora and fauna. The "good" bacteria. Bascillus is 1 of those. These good bacteria have been shown to reduce the chances of aeromonas and other bacteria from being harmful to our fish and even ourselves. Bascillus subtilis is sold as a human prophylactic.
Tammy

Good write up Tammy.

Great info, thanks Tammy.