Flesh-eating bacteria lurking in the sea

Five people have died from “flesh-eating bacteria” in the Tampa Bay area this year.The pathogen is called Vibrio vulnificus, occurs naturally in warm salty seawater. So far in 2023, Florida has reported a total of 25 cases.

Although this infection is rare, it is especially dangerous for those who have open wounds or eat raw shellfish such as oysters. If the bacteria gets into the bloodstream, it can be fatal 50% of the time. To prevent infection with this microorganism, it is recommended to stay out of the sea if you have cuts on your skin, cook shellfish properly, and wear protective clothing when handling shellfish.

he Vibrio vulnificus It is a type of Bacillus belonging to the genus Vibrio, the same as Vibrio. Vibrio cholerae, the causative agent of cholera, we recently dedicated an article to. It is a bacterium that can survive in an oxygen-free environment, is rod-shaped and supports high alkalinity. Especially dangerous for people with compromised immune systems such as diabetics, steroid users, cancer patients…

This pathogen can cause three pictures. First, after ingesting contaminated food, gastrointestinal symptoms such as diarrhea, vomiting, abdominal pain, and fever may occur. Second, and most serious, when the bacteria are able to reach the bloodstream, the clinical features are fever, chills, a drop in blood pressure and, in severe cases, Shock septic tank. The mortality rate in this picture is close to 50%. Finally, when it infects open wounds, it is capable of producing soft tissue infections, which can be disfiguring and, in many cases, fatal.

Flesh-eating bacteria?

When you read the term “flesh-eating bacteria,” you think of a type of bacteria that literally eats human flesh. Will this really happen?noel Vibrio vulnificus and other bacteria that do not eat meat. However, the pictures they make might make people think they did.

These are so-called necrotizing soft tissue infections. These pictures are characterized by appearance on the extremities and perineal area. It’s important to remember that the perineum is the part of the body that creates the pelvic floor, where the anus and external genitalia are located. It consists of muscles and ligaments that mimic the shape of a diamond.

When a bacterial infection develops in these areas, the small blood vessels in the skin and subcutaneous tissue become blocked due to toxins and other complex mechanisms. This occlusion can lead to a heart attack and necrosis (death) of these tissues.This in turn promotes the growth of these bacteria, which are able to survive anaerobically, that is, in the absence of oxygen, permanently or permanently, like Vibrio vulnificus. A vicious cycle then ensues, with more toxins being produced, more blood vessels getting clogged, more tissue necrosis (death), and giving the impression that the bacteria is “eating meat” because all the dead it has Or damaged tissue is surgically removed (cut). Failure to do so will almost certainly result in the death of the patient.

A Brief History of Necrotizing Soft Tissue Infections

The first description of such diseases dates back to the 5th century BC, recorded by Hippocrates. In 1871, during the American Civil War, military doctor Joseph Jones mentioned in detail the disease that affected 2,642 soldiers and the death rate was close to 50%, calling it “hospital gangrene” instead of the so-called “gas gangrene” in the classic picture. Characterized by the presence of gas at sites of necrosis.

Later, in 1883, A. Fournier, a French physician devoted to sexually transmitted diseases, published a detailed description of the necrotizing infection of the perineum, which is now known as “Fournier’s gangrene” in honor of this doctor. It was not until 1924, when surgeon Frank L. Meleney isolated streptococci from the blood cultures of 20 patients in Beijing, that the causative bacteria in most cases were determined to be streptococci and created the The names “streptococcal gangrene”, “acute hemolysis”.

Death rates from these diseases have changed little in recent years, despite a better understanding of the disease and more effective treatment tools. But what structures does this painting involve? Why is it called a soft tissue infection? What are those “soft tissues”? What germs are involved?

Necrotizing soft tissue infection

Before continuing, we must pause to explain what we mean by soft tissues and the structures that make them up. In this case, we’re talking about the deepest layer of the skin and an important and little-understood structure called the muscle fascia.

The skin consists of three layers:

• epidermis (outermost layer)
• Leather (Intermediate)
• subcutaneous tissue (deeper)

For the purposes of this article, we will only refer to the last two. There are sensory receptors in the dermis that allow the body to receive external stimuli and respond to pressure, pain and temperature. There are also blood vessels, which provide the skin with necessary oxygen and nutrients and remove waste products. Finally, we find different glands, such as the sebaceous glands, which produce skin oils that keep the skin from drying out. They appear all over the body except the palms and soles of the feet. The deepest layer of the skin is the subcutaneous tissue. It contains fat cells, or adipose tissue, which insulate the body, help the body conserve heat, and constitute vital energy reserves.

Immediately below the skin is the muscle fascia. One of the functions of this structure is to hold the muscles together and in the correct position; to separate them so they can work independently, and to provide a lubricated surface so they can move smoothly over each other.

Necrotizing soft tissue infections affect the dermis, subcutaneous tissue, and fascia, causing cellulitis, subcutaneous infection, and necrotizing fasciitis, depending on the structures affected.

Although Vibrio vulnificus It is this germ that sparked this essay, the least common and the most important of those that usually lead to these paintings. Infections caused by it are classified as group 3 or type 3. Type I infections are those caused by more than one pathogen, known as “polymicrobial,” often occur in diabetic and immunosuppressed patients, and often produce gas, which is why they are reminiscent of “gas gangrene.” Finally, type II infections are produced by a single bacterium, usually strep or staph. It is usually seen in younger patients with a history of drug use, accident, or recent surgery.

Clinical manifestations and treatment

The main symptom of necrotizing soft tissue infection is severe pain. In patients with normal sensations, the onset of pain is out of proportion to the extent of the lesion observed. Affected areas are often red, hot, swollen and quickly turn pale, which is a bad sign. Crackling blisters may appear, that is, they make a sound reminiscent of a plastic bag when squeezed in the hand. This occurs due to the presence of gas in the subcutaneous tissue.

Muscles may be preserved at first, but as the disease progresses and deepens, they become affected. The patient became seriously ill, with high fever, rapid heart rate, altered mental status (ranging from confusion to marked lethargy), and decreased blood pressure.

Treatment of necrotizing soft tissue infections is surgical and should not be delayed. Because the condition is serious and life-threatening, the operation must be repeated every 1 or 2 days, and the incision is large. Amputation of the affected limb is sometimes required. Intravenous antibiotics are adjunctive medications and usually include two or more drugs. Large volumes of intravenous fluids may be needed before and after surgery. Hyperbaric oxygen therapy may also be beneficial.

gangrene and other infections Clostridium perfringens

Among necrotizing soft tissue infections, because of their importance, a special case refers to infections produced by a bacterium called soft tissue infection. Clostridium perfringens. They usually develop hours to days after a severe crush injury to a limb or a penetrating injury that severely damages tissue and creates anaerobic conditions (that is, lack of oxygen). Infection may also occur at the surgical incision.

Infections with this pathogen range from cellulitis (in superficial wounds) to myositis (if muscles are affected). Myositis, understood as an infection of the muscles without necrosis (death), is more common in drug users. Sometimes it leads to a very serious condition called “clostridial myonecrosis”. This picture is a medical classic, commonly known as “gas gangrene”.

As the image progresses, toxicity in the body increases, along with increased heart rate, pallor, and a drop in blood pressure. Organs and systems, such as the kidneys, then begin to fail. What makes it special is that the patient usually remains conscious until near death.

Because this condition progresses rapidly, surgery is critical, along with high doses of penicillin and other drugs, and the use of hyperbaric oxygen (that is, under high pressure).