When fulfilling a sushi craving, most people don’t consider any risks associated with the consumption of raw seafood; after all, why would you? When was the last time someone you knew ate some sashimi and ended up with a raging infection that destroyed essential body parts?
Food safety standards in developed countries tend to preclude devastating food-bourne infections, but not everyone is so lucky, as you will see in some examples described below.
In 2017, a woman in the United States was visiting some friends and family, and during the course of her visit, she consumed some raw oysters. Less than a month later, she was dead. She began to experience difficulty breathing and developed a rash on her legs hours after eating the infected oysters. As her condition did not abate and her rash and breathing problems became worse, she went to the hospital and was told that she had been infected with Vibrio vulnificus, a “flesh-eating” (causes tissue to necrotize, or die) species of bacteria that can be contracted by consuming raw seafood or via open wounds.
Typically, consuming seafood contaminated with Vibrio species is not fatal (with only 15-30 % of cases result in death); for the most part, symptoms of infection result in the usual symptoms of food poisoning, with people experiencing nausea and diarrhea. However, infections from more virulent species such as Vibrio vulnificus can result in limb amputations or death.
Earlier in July of this year, a man from the United States who went fishing for crab was infected with Vibrio vulnificus. The likely source of infection was an open wound in one of his leg where the bacteria entered his system. Within a day of his crabbing adventure, the man’s legs had become painfully swollen and a strange dark brown-black color. At the hospital, the man was treated with antibiotics, but the blisters and sores developing on his legs began to spread and his kidneys began to fail. Doctors are hoping that the antibiotics administered will be able to fight off the infection of Vibrio vulnificus, but it is possible that most, if not all, of his limbs may need to be amputated in order for him to survive.
This last week, a man from South Korea consumed raw seafood and, mere hours later, his hands began to painfully swell and to develop blisters filled with blood (called hemorrhagic bullae). After two days, he went to the hospital with a fever and was treated with antibiotics while the blood was drained from the hemorrhagic bullae on his hands. The blood drained from the hemorrhagic bullae was analyzed, and Vibrio vulnificus was identified from within the blood. Despite receiving antibiotics, the hemorrhagic bullae on the man’s hands became necrotic and his left arm was removed after 25 days. Once his arm had been amputated, the man recovered enough to be sent home.
What Is Vibrio vulnificus?
Vibrio vulnificus is a gram-negative (does not retain crystal violet dye in the cell wall due to the thin layer of peptidoglycan in the cell wall) rod-shaped bacteria. Relatives of Vibrio vulnificus include the bacteria that can cause cholera, Vibrio cholerae. Vibrio vulnificus is found primarily in warm salt water along the coast, and in brackish water.
As mentioned above, Vibrio vulnificus can cause infections resulting in the need to amputate limbs, or it can even result in death. Amputation and/or death due to Vibrio vulnificus is caused by the ability of the bacteria to cause sepsis or necrotic tissue. Sepsis is an infection that has gained access to the blood leading to an overreaction of the immune system and inflammation throughout the whole body via the circulatory system. Sepsis can lead to shock, organ failure, and death. Necrotic tissue occurs when large numbers of cells die unnecessarily in living tissue and begin to decompose. Necrotic tissue can appear to be a yellowy cream of thick liquid, white crumbly clumps, or dried and blackened patches. It is important that any necrotic tissue is removed either by debridement or amputation as quickly as possible.
Treatment of Vibrio vulnificus tends to be the application of antibiotics; currently, the most effective antibiotic treatment is a combination of doxycycline and ceftazidime. Due to the widespread application of antibiotics to treat various infections, resistance to antibiotics is on the rise and is making the treatment of infections such as Vibrio vulnificus with antibiotics more and more difficult. If any necrosis has occurred, surgery is also required to fully treat the infection.
What Can be Done to Prevent Infection by Vibrio vulnificus?
Since the bacteria can enter the body via two routes (i.e. through the consumption of raw and contaminated seafood or water or open wounds exposed to any substance containing the bacteria), preventing an infection is centered on those two areas. Infection may be prevented by avoiding consuming contaminated seafood and ensuring seafood is well cooked prior to consumption, although thorough cooking may not fully prevent infection if contaminated seafood is consumed.
People with compromised immune systems, liver disease, heart disease, or diabetes should probably avoid eating uncooked seafood at all. Being aware of when and where seafood products such as oysters or mussels run higher risks of being contaminated with Vibrio is also a good idea. Another possible entry route is through open wounds in the skin, through which bacteria may enter the bloodstream and cause infections. Make sure not to swim in or come into contact with possibly contaminated water or seafood if there are any unhealed open wounds, or even small punctures, in your skin.
If you do swim in possibly contaminated waters and have an open wound, cover it with a waterproof bandage. Wash your wound immediately with soap and water if any contaminated water may have touched your wound, and apply an antibiotic ointment. Watch for any signs of infection such as swelling and seek immediate medical treatment if signs of infection occur.