"When it gets into those deeper tissues, it has a remarkable ability to destroy the tissues that surround it in sort of this hunt for nutrition," Creech said Friday. "When it does that, those tissues die, and you see the inflammation and the swelling and the destruction that can be very difficult to control."

Creech said Aeromonas hydrophila more commonly affects humans when it is swallowed – resulting in diarrhea. When young children or children with immune problems drink water with the bacteria, "they can get a very significant diarrhea illness from it," he said.

"It's much more uncommon that we see it in (a case like Copeland's), where we see wounds get infected and the infection runs wild,” Creech said.




On May 1, 1988 there was a small Aeromonas hydrophila outbreak in California. There were 225 isolates and 219 patients admitted in the hospital because of the bacterium. Confidential Morbidity Report cards were used to report the cases of the bacterium to the local health departments. Investigations were conducted, and reports were sent to the California department of health services for diagnosis and methods in treatment.

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DISCUSSION

Aeromonas hydrophila is a motile gram-negative bacillus found in water sources that can cause a wide range of human illness, including acute gastroenteritis, soft tissue infections, meningitis, hepatobiliary tract infections, peritonitis, pneumonia, empyema, and primary septicemia (1-5). Possible routes of transmission include intake of contaminated food, exposure of wounds to environments that contain the pathogen (1-8). Severe soft tissue infections caused by Aeromonas hydrophila usually involve people with chronic illness, such as cirrhosis, malignant diseases, chronic renal failure, diabetes mellitus, or steroid use (3,4). 

Aeromonas hydrophila complex is probably the most commonly encountered bacterialpathogen of freshwater fishes. These bacteria are motile (capable of moving), and severaldifferent species may be responsible for Motile Aeromonad Disease (MAD). In addition to A.hydrophila, bacteria that have been implicated in MAD include A. sobria, A. caviae, and A.veronii. These are ubiquitous (found almost everywhere) organisms and opportunisticpathogens that take advantage of stressed and immunocompromised fishes. Environmentalstresses such as crowding, temperature extremes, poor nutrition, and transport all maypredispose fishes to MAD. 
Aeromonas hydrophila can be eliminated using one percent sodium hypochlorite solution and two percentcalcium hypochlorite solution.
(what does eating that do?)

Antibiotic agents such as chloramphenicol, florenicol, tetracycline, sulfonamide, nitrofuran derivatives, and pyrodinecarboxylic acids are used to eliminate and control the infection of Aeromonas hydrophila.
  1. http://en.wikipedia.org/wiki/Aeromonas_hydrophila
    ^     Prevalence and distribution of Aeromonas hydrophila in the United States
  2. ^ Clinical and microbiological features of Aeromonas hydrophila-associated diarrhea

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CASE REPORT

The 60-year-old man was brought to the emergency room with pain, swelling, and erythema involving his left leg of one-day duration, which was accompanied by fever and chills. His medical history was notable for cirrhosis and type-two diabetes. The patient denied a history of prior wounds on the left lower extremity. On examination, there was marked circumferential, diffuse swelling of the leg, and subsequent development of multiple hemorrhagic bullae over a large area. During the course of the day, friable and malodorous changes developed rapidly (Figure 1).
Figure 2. The left lower limb after extensive debridement
Figure 2. The left lower limb after extensive debridement



 The patient was resuscitated, and was subsequently transferred to the surgical intensive care unit. Histopathological examination of the specimen showed extensive necrotizing fasciitis and pyomyositis. Wound cultures grew gram-negative bacilli, which were identified asAeromonas hydrophila. Although our team staff had commenced aggressive medical and surgical therapies, the patient died due to multi-organ failure on the third day of admission.



Preventing infection

It is ill-advised to transfer fish from hatchery to hatchery without any sanitation. Hatchery workers should clean the fish, and check for bacterial infection between each operation. To avoid contamination oxygen levels in fish should be maintained, and fish should always be handled gently, to avoid injury.Prophylactic treatments can also be used when trying to prevent Aermonas hydrophila. These treatments include disinfectants and Acriflavine.





Human diseases

Aeromonas hydrophila is not as pathogenic to humans as it is to fish and amphibians. One of the diseases it can cause in humans is gastroenteritis. This disease can affect anyone, but it occurs most in young children and people who have compromised immune systems or growth problems. This bacterium is linked to two types of gastroenteritis. The first type is a disease similar to cholera, which causes rice-water diarrhea. The other type of disease is dysenteric gastroenteritis, which causes loose stools filled with blood and mucus. Dysenteric gastroenteritis is the most severe out of the two types, and can last for multiple weeks. Aeromonas hydrophila is also associated with cellulitis, an infection that causes inflammation in the skin tissue. It also causes diseases such as myonecrosis and eczema in people with compromised immune systems.




Fish and amphibians

Aeromonas hydrophila is associated with diseases mainly found in fish and amphibians, because these organisms live in aquatic environments. It is linked to a disease found in frogs called red leg, which causes internal, sometimes fatal hemorrhaging. When infected with Aeromonas hydrophila, fish develop ulcers,tail rot, fin rot, and hemorrhagic septicaemia. Hemorrhagic septicaemia causes lesions that lead to scale shedding, hemorrhages in the gills and anal area, ulcers, exophthalmia, and abdominal swelling.



Occurrence of exposure

Aeromonas hydrophila infections occur most during environmental changes, stressors, change in the temperature, in contaminated environments, and when an organism is already infected with a virus or another bacterium. It can also be ingested through food products that have already been infected with the bacterium, such as seafood, meats, and even certain vegetables such as sprouts.

Because of Aeromonas hydrophila’s structure, it is very toxic to many organisms. When it enters the body of its victim, it travels through the bloodstream to the first available organ. It produces Aerolysin Cytotoxic Enterotoxin (ACT), a toxin that can cause tissue damage. Aeromonas hydrophila, Aeromonas caviae, and Aeromonas sobria are all considered to be opportunistic pathogens, meaning they rarely infect healthy individuals. Aeromonas hydrophila is widely considered a major fish and amphibian pathogen,[1] and its pathogenicity in humans has been recognised for decades.[2]

Aeromonas hydrophila is a heterotrophic, Gram-negative, rod shaped bacterium, mainly found in areas with a warm climate. This bacterium can also be found in fresh, salt, marine, estuarine, chlorinated, and un-chlorinated water. Aeromonas hydrophila can survive in aerobic andanaerobic environments. This bacterium can digest materials such asgelatin, and hemoglobin. Aeromonas hydrophila was isolated from humans and animals in the 1950s. This bacterium is the most well known of the six species of Aeromonas. It is also highly resistant to multiple medications, chlorine, and cold temperatures.

Can grow in temperatures as low as four degrees Celsius.