The Danger of Eating Contaminated Raw Oysters

The Vibrio bacterium vulnificus, that appeared in End of the East and Piriápolis between December and January, infected four people of who two passed away. To be Doctor talked with the Dr. Julio Medina, professor added of the Chair of Infectious Diseases of the University of the Republic.

Medina explained that the sort Vibrio it is classified within the family Vibrionaceae, being most excellent: Vibrio cholerae and Vibrio parahaemolyticus, diarrea causes, and Vibrio vulnificus associated to invasive and serious infections.

Vibrio vulnificus it is a curved, anaerobic bacillus Gram-negative facultative and halófilo cause of two defined clinical organizations good according to the front door of the microorganism. One is the primary sepsis due to marine the product ingestion (clams and other seafood or fish) badly cooked or crude, specially in inmunodeprimidos patients. The other is the infection of soft parts (cellulitis, miositis and/or necrosante fascitis) through contact with the water of sea of preexisting or acquired wounds in the marine atmosphere.

This bacterium can be found in coastal marine waters and estuaries in zones of tropical and subtropical climates that have moderate degree of salinity and temperatures that usually surpass 18°C. With regard to the seafood, the moluscos, that are filters, acquire Vibrios like part of its normal microflora during the summer months.

Really, the consumption of seafood, the exhibition to the water through the sport and recreational activities, and the increase of the density of vibrios in marine waters during the warmest months they are the causes that explain this seasonal tendency of the infections.

Some coastal regions of the United States of America (EE.UU.) like the coastal regions of Florida, Gulf of Mexico, the New England and the northeast of the Pacific are more prone to the reproduction of this microorganism, as well as some areas of China and Thailand, according to explains the specialist. With respect to the region, isolated cases of serious infection in Latin America have been reported, like in Chile, Brazil, Peru and Uruguay. The first case in Uruguay, reported in Literature, dates from 2001 and corresponds to a sepsis by Vibrio vulnificus, explain Medina.

Infection risk

After exposure, the microorganisms reach the bloodstream through the skin or mucosa invasion and multiply intestinal producing haemolysins, cytolysins and proteases that cause extensive cell damage and are involved in the development of sepsis. Iron is an important factor of growth of bacteria- therefore, patients with hemochromatosis and hemolytic anemia are especially prone to the development of infection by this organism group, said the infectious disease.

Other risk groups are carriers of liver disease such as cirrhosis, hepatitis B and C; Cancer; HIV AIDS; thalassemia; aplastic anemia; kidney or liver transplant; Patients receiving immunosuppressive therapy (chemotherapy, corticosteroids, cyclosporine, tacrolimus); hemodialysis patients; splenectomized and diabetics.

clinical picture and mortality

The mortality rate of 25% is the highest among infections due to Vibrio spp and Vibrio vulnificus is estimated to represent 90% of all deaths related to consumption of seafood in the United States.

With regard to soft tissue severe sepsis mortality can reach 50% or even be higher as comorbidities, patient's immunity, multiple organ dysfunction, septic shock evolution or compartment syndrome, among others.

Most patients who develop sepsis are between 50 and 60 years, with 82% men.

In immunocompromised patients, Medina explains, it has the ability to invade the bloodstream without causing gastrointestinal symptoms. The clinical picture is characterized by a sudden onset of chills and fever, followed often (1/3 cases), hypotension and generally (3/4 cases), metastatic skin lesions after 24 -48 hours of onset. These lesions begin as erythema rapidly evolving to hemorrhagic blisters or vesicles and post necrotic ulcers. Cellulite is intense and develops rapidly with necrotizing vasculitis and the formation of an ulcer is both healthy individuals and in immunocompromised hosts, bacteremia is frequent.

"Physicians should be aware of various etiologies when faced with a severe soft tissue infection: Streptococcus group A, Staphylococcus aureus, polymicrobial, Pseudomonas sp, Clostridium perfringens, Pasteurella multocida, Aeromonas hydrophila among others, where Vibrio vulnificus is an etiology little frequent but we must remember, "he says.

Treatment

In the treatment of severe soft tissue infection caused by Vibrio vulnificus is decisive early surgical approach and the administration of appropriate antibiotics because the process can progress rapidly. Should be consulted early the surgeon for debridement of all devitalized tissue, alert the doctor. He adds that the recommended antibiotic treatment is a combination therapy with intravenous cefotaxime or ceftazidime 2 g every 8 hours or ceftriaxone 1 gram every 12 hours + doxycycline 100 mg orally or intravenously (in Uruguay are not available intravenous doxycycline). Instead of doxycycline is also alternative ciprofloxacin 400 mg intravenously every 8 hours or 500 mg levofloxacin intravenously or orally every 12-24 hours. The adjustment of doses and routes of administration depend on the severity of the infectious process. There are even reported cases of antibiotic triple therapy in severely ill patients with septic shock made by one of the beta-lactams described + one of the quinolones described + doxycycline.

Prevention

Currently, the only effective means of prevention is thorough cooking of fish and seafood, especially for the population at risk and analyzed. Do not eat shellfish that do not open during cooking. It is important to wear gloves when handling raw shellfish or oysters.

They should also avoid exposure of open seawater especially wounds when its temperature is above 18 ° C.

People with open wounds should wash any wound that is exposed to seawater with fresh water and soap. Immediately seek medical attention for any wound that appears infected or severe lower limbs pain.

People at Greater Risk

People who drink alcohol regularly may be at risk of developing liver disease and, consequently, increased risk for serious illness or death from consuming raw oysters contaminated by bacteria.

"Drinking two to three alcoholic drinks per day can cause liver disease and liver can deteriorate several years before an individual begins to experience symptoms," "These people may have higher risk for infection from Vibrio vulnificus without even knowing ".

In addition, diabetes, cancer, stomach disease, iron overload disease or any illness or medical treatment that weakens the immune system may increase the risk of infection from Vibrio vulnificus.

Am I infected?

Potentially with threats to the lives of most people, symptoms of infection from Vibrio vulnificus occur within 24 to 48 hours after ingestion of contaminated raw oysters and may include symptoms such as sudden chills, fever, nausea, vomiting, diarrhea, shock and skin lesions. In the case of certain diseases such as cancer, diabetes or liver disease, death can occur within two days. A person who has any of these symptoms after eating raw oysters should seek medical attention immediately and inform the professional duty doctor who has eaten raw oysters.

Risk reduction

Vibrio vulnificus bacteria are not the result of pollution, so although oysters purchased in reputable sites, eating oysters from "clean" waters or recognized with high turnover does not provide protection restaurants.

"Many people believe that adding lemon juice or hot sauce oysters will kill the bacteria." "The truth is that only heat can destroy the bacteria, so the next time you want to eat oysters cook them well when eating cooked at home or order them when eating at a restaurant."

For more information on the risks associated with eating raw oysters, call your doctor trust.

eating Oysters

In restaurants:

Order oysters fully cooked.

Cooking at Home:

When you purchase oysters the shells should be closed. Throw away any oysters with shells already opened.

In the shell: After the shells open, boil live oysters for another 3 to 5 minutes. (Use small to boil or steam oysters pots. Do not cook too many oysters in the same pot as those in the middle may not be fully cooked. Discard any oysters that do not open during cooking).

In a steamer: Add oysters to water that is already steaming and cook live oysters for 4 to 9 minutes.

Shucked oysters:

Boil or simmer shucked oysters for at least 3 minutes or until the edges curl.

Fry at 375 degrees for at least 3 minutes.

Broil 3 inches from heat for 3 minutes

Bake at 450 degrees for 10 minutes.