Aeromonas hydrophila

Background

Aeromonas Hydrophila is a pathogen that is commonly found in amphibians, fish, reptiles, snails, cows, and sometimes humans
It is typically found around aquatic habitats, varying salinity levels, or in fish. Many humans contract when they enter waters with an open wound and the water has A. hydrophila.
A. hydrophila can cause ulcer diseases in cod, diarrea, bone infections, and extraintestinal infections
People should care about the prevalence of Aeromonas hydrophila because of the fact that it is a direct pathogen to fish and can be found in marine environments
- the Impact of A. hydrophila extends more than just the fishing industry it also effects the tourist industry and coastal communities as a result.

Visualizing and growing A. hydrophila

Gram Stain of A.hydrophila

From this we can see that it is a gram-negative bacteria

Scanning Electron Microscope of A. hydrophila

Transmission Electron Microscope view of A.hydrophila

Confocal Laser Scanning Microscope of A. hydrophila

What is your microbes BSL? 2
What type of agar do you need? You can use a nutrient agar medium that is 23 g agar and 1000ml of DI water or Tryptic Soy Broth.
Does it need to be in a anaerobic or aerobic setting? It can grow in an aerobic setting.
What is the procedure for growing it once it arrives? Let the freeze-dried sample thaw and after a while transfer it into a medium of tryptic soy broth so grow more organisms. After letting the broth be inoculated for 48 hours, transfer the A. hydrophila to a nutrient agar plate
When was the first documentation of Aeromonas hydrophila? The first documentation of the A. Hydrophila or even the Aeromonas in 1967, when a whole pure culture of A. hydrophila was isolated from a man with tonsillitis.

Differentiation of Aeromonas hydrophila

Below are test that can be used to different A. hydrophila from other microorganisms but the closest organism that A. hydrophila can be confused with and that is Aeromonas salmonicida.

Blood Agar Plate

The Blood Agar plate test for hemolysins activity. A. hydrophila has beta hemolysis as seen around the colonies it is yellow.

MacConkey Agar Plate

MacConkey agar plates are used to selective grow gram negative microorganisms. Lactose fermentation can also be determined, and it will change the plate pink in their areas.

In the case of A.hydrophila it is a gram negative species and is able to grow on the MacConkey agar plate, but it is not lactose fermenting so it makes sense that the colonies on the left do not have any pink areas around it.

Mannitol sugar plate

The Mannitol salt agar is used to differentiate microorganisms that undergo mannitol fermentation. If the microorganism undergoes mannitol fermentation there would be a color change to pink and if there is no mannitol fermentation it would have no color change.

A.hydrophila does undergo mannitol fermentation so it will turn pink on the plate.

DNAse plate

The DNAse test plate is used to measure DNA activity. Methyl green can be broken down via DNA polymerase. If there is DNA activity the area where the microorganisms the plate will become clear around it.

A.hydrophila does have DNA activity so it will be clear around it similar to the area where A is labeled. I could not find a plate with A. hydrophila on it.

Phenol Red broth Test

Phenol red broth test are used to test for fermentation of different carbohydrates. A positive test for fermentation has a color change to yellow and a negative test would be no color change.

Hydrophila does undergo glucose fermentation and gas production so it will result the last tube where there is yellow color and an air bubble in the tube .

SIM motility Test

The SIM medium agar is useful in testing multiple different things. SIM tests for hydrogen sulfide production, Indole, and motility. This image is a test for motility.

A. hydrophila does not produce hydrogen sulfide, is motile, and does undergo indole production

Catalase Test

The catalase test is used to indicate production of oxygen, A positive test will result in bubbling on the plate.

A. hydrophila does produce oxygen so it will result in the image to the left.

Oxidase Test

The oxidase test, tests for the presence of cytochrome C and it requires oxidase to test for this. A positive test will result in color change of purple while a negative change will remain colorless.

A.hydrophila is positive for cytochrome C so under this test it will result in a color change to purple as seen to the left.

Treatment and Prevention

Ways to prevent infection from A. hydrophila
- Correct treatment and disinfection of drinking water
- Rehydration therapy is important in pediatric cases of infection
- Possible surgical invention if necrotizing fasciitis occurs

What antibiotics work against your bacteria? Are there any other treatments for it?
- Abacavir is an antibiotic successful in treating for A. hydrophila
- In some cases, surgical intervention may be needed if there is necrotizing fasciitis
- In Biliary Tract infections, proper drainage is necessary
- In soft tissue infections, cefotaxime and minocycline is recommended as a form of antibiotic therapy in a posttraumatic wound
- There are no vaccines.

Molecular Diagnostics of A.hydrophila

What are the primers you are using? (These were taken from literature)
- A16S
  - GGG AGT GCC TTC GGG AAT CAG A
  - TCA CCG CAA CAT TCT GAT TTG
What is the melting temperature?
- 59 degrees celsius
- 50 degrees celisus
What is the GC content?
- 59%
- 43%
Full 16s sequence of rRNA for Aeromonas Hydrophila
- TCGAGCGGCAGCGGGAAAGTAGCTTGCTACTTTTGCCGGCGAGCGGCGGACGGGTGAGTAATGCCTGGGGATCTGCCCAGTCGAGGGGGATAACAGTTGGAAACGACTGCTAATACCGCATACGCCCTACGGGGGAAAGGAGGGGACCTTCGGGCCTTTCGCGATTGGATGAACCCAGGTGGGATTAGCTAGTTGGTGGGGTAATGGCTCACCAAGGCGACGATCCCTAGCTGGTCTGAGAGGATGATCAGCCACACTGGAACTGAGACACGGTCCAGACTCCTACGGGAGGCAGCAGTGGGGAATATTGCACAATGGGGGAAACCCTGATGCAGCCATGCCGCGTGTGTGAAGAAGGCCTTCGGGTTGTAAAGCACTTTCAGCGAGGAGGAAAGGTTGATGCCTAATACGCATCAGCTGTGACGTTACTCGCAGAAGAAGCACCGGCTAACTCCGTGCCAGCAGCCGCGGTAATACGGAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGCGCACGCAGGCGGTTGGATAAGTTAGATGTGAAAGCCCCGGGCTCAACCTGGGAATTGCATTTAAAACTGTCCAGCTAGAGTCTTGTAGAGGGGGGTAGAATTCCAGGTGTAGCGGTGAAATGCGTAGAGATCTGGAGGAATACCGGTGGCGAAGGCGGCCCCCTGGACAAAGACTGACGCTCAGGTGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACGCCGTAAACGATGTCGATTTGGAGGCTGTGTCCTTGAGACGTGGCTTCCGGAGCTAACGCGTTAAATCGACCGCCTGGGGAGTACGGCCGCAAGGTTAAAACTCAAATGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGATGCAACGCGAAGAACCTTACCTGGCCTTGACATGTCTGGAATCCTGCAGAGATGCGGGAGTGCCTTCGGGAATCAGAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCCTGTCCTTTGTTGCCAGCACGTAATGGTGGGAACTCAAGGGAGACTGCCGGTGATAAACCGGAGGAAGGTGGGGATGACGTCAAGTCATCATGGCCCTTACGGCCAGGGCTACACACGTGCTACAATGGCGCGTACAGAGGGCTGCAAGCTAGCGATAGTGAGCGAATCCCAAAAAGCGCGTCGTAGTCCGGATCGGAGTCTGCAACTCGACTCCGTGAAGTCGGAATCGCTAGTAATCGCAAATCAGAATGTTGCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTGCACCAGAAGTAGATAGCTTAACCTTCGGGAGGGCGTT

About the Researcher

Hey Guys! My name is Ethan Pham and this semester I had the opportunity to learn more about the Aeromonas hydrophila (This is not my cat but you can tell that it loves me very much)

Fun Facts about me!

I am from Tampa, Florida, Born and raised baby!
Currently I am in the Class of 2023 at the University of Florida as a microbiology major and on the pre-med track
In the future I hope to work in the Emergency medicine setting as physician
I spend most of free time out in nature and near the waters.
I am a big plant person and in the past two weeks I have collected 6 plants.

Resources

Du H, Pang M, Dong Y. 2016. Identification and Characterization of an Aeromonas hydrophila Oligopeptidase gene pepF Negatively related to Biofilm Formation. Front Microbiology vol 7. Doi: 10.3389/fmicb.2016.01497

Gilardi G. 1967. Morphological and Biochemical Characteristics of Aeromonas punctata (hydrophila, liquefaciens). Applied Microbiology Vol. 15 (no.2): pg.417-421

Hussain I.A, Jeyasekaran G, Jeya Shakila R., Jeevithan E. 2013. Detection of hemolytic strains of Aeromonas hydrophila and A. sobria along with other Aeromonas spp. from fish and fishery products by multiplex PCR. J Food Sci Technol. 51(2): 401-407 DOI: 10.1007/s13197-013-1190-9

Hazen T, Fliermans C, Hirsch R, Esch G. 1978. Prevalence and Distribution of Aeromonas hydrophila in the United States. Applied EM Vol.36 No.5. pg. 731-738

Igbinosa I, Igumbor E, Aghdasi F, Tom M, Okoh A. 2012. Emerging Aeromonas Species Infections and Their Significance in Public Health. SWJ. DOI: 10.1100/2012/625023

Kok N. 1967. Aeromonas hydrophila isolated from tonsillitis in man. Report of a case. Acta Pathologica et Microbiologica Scandinavica Vol. 71 (No.4): pp. 598-602. ISSN: 0365-555

Peterman MA, Posadas BC. 2019. Direct impact of Fish Diseases on the East Mississippi Catfish industry. North American Journal of AGC 81:222-229 DOI: 10.1002/naaq.10090

Shotts E, Rimler R. 1973. Medium for the Isolation of Aeromonas hydrophila. Applied Microbiology Vol. 26 (No.4): p 550-553.

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