The AMR Narrative

Vancomycin-resistant Enterococci (VRE)

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What are vancomycin-resistant Enterococci (VRE)?

Vancomycin-resistant Enterococci (VRE) are a type of Enterococci bacteria resistant to vancomycin, a type of last-line antibiotics used to treat serious multidrug-resistant bacterial infections.

Unfortunately, Enterococci have the ability to develop antibiotic resistance through a variety of mechanisms.

Indeed, VRE bacteria can change some parts of their cell wall. This way, they prevent vancomycin and the other beta-lactam antibiotics (such as penicillin) to bind to the bacteria, making these medications ineffective. Some VRE are even resistant to all available antibiotics, making these types of infections very difficult to treat.

Moreover, VRE can share their genetic material with other Enterococci bacteria (through the so-called plasmids, small circular DNA molecules), rapidly spreading resistance.

That is why VRE are considered a serious public health threat, and specifically vancomycin-resistant Enterococcus faecium has been listed among the top priority bacterial pathogens to guide discovery, research and development of new antibiotics by the World Health Organization (WHO).

What are Enterococci?

To understand VRE, it is important to know what Enterococci are.

Enterococci are gram-positive bacteria. When observed under a microscope, they are spherical-shaped, and typically tend to be arranged in short and medium chains.

There are several species of Enterococci, the most important and common being Enterococcus faecalis and Enterococcus faecium.

They are common cause of hospital-associated infections. Enterococci can cause various types of infections ranging from mild to serious ones, such as urinary tract infections, bacteremia, and endocarditis. Life-threatening conditions primarily occur in healthcare settings, for example hospitals and nursing homes, and mainly affect people with specific risk factors.

Where can Enterococci be found?

Enterococci are normally present in the large intestine (indeed, “éntero” is a Greek word meaning intestine), and in the female genital tract, as part of the normal flora. They are also found in the environment, like in soil and water.

Therefore, Enterococci can colonize the gastrointestinal tract, living in a patient without causing symptoms or signs of infections. However, colonization can lead to infection in certain groups of people who are at greater risk than others.

How can Enterococci spread?

Since Enterococci live in the environment, they can be spread to people when they are exposed to water or soil contaminated with these microorganisms.

In healthcare facilities bacteria can spread from person to person by skin contact with infected or colonized people (such as through healthcare workers’ contaminated hands), or contaminated medical equipment or environmental surfaces.

Moreover, Enterococci are able to survive for long periods of time in a wide variety of conditions and environments, including extremely high and low temperatures. These abilities make them easily transmissible in healthcare settings.

Which infections can Enterococci cause?

Enterococci can cause a variety of infections, ranging from mild to life-threatening conditions.
They include:

• Urinary tract infections. They represent the most common infections caused by Enterococci, usually occurring in people with urinary catheters. Any part of urinary system can be infected, including kidneys (pyelonephritis), bladder (cystitis), and prostate (prostatitis).
• Bacteremia. This occurs when bacteria overcome the defence mechanisms of the body (for example, through a wound, or a urinary or an intravascular catheter), and by spreading through the bloodstream.
• Endocarditis. In this serious and life-threatening condition, bacteria stick to one of the valves inside the heart after spreading into the bloodstream.
• Skin and soft tissue infections. Enterococci can infect skin, and even the tissues immediately beneath the skin (cellulitis). These conditions are more common in people with pressure sores, burns, and wounds due to injuries or surgery.
• Intra-abdominal and pelvic infections. These conditions occur when bacteria cause abscesses inside the abdomen, or a peritonitis (a life-threatening infection of the peritoneum, a membrane that lines most of the outer surfaces of the digestive organs).

Who is at risk of enterococcal infections?

Anyone can develop an enterococcal infection, but certain groups of people are at greater risk than others, including people and include those:

• with chronic diseases, such as cancer;
• with a weakened immune system, such as from immunosuppressants (medications which slow or stop the response of the immune system), or cancer chemotherapy;
• with urinary or intravenous catheters;
• with wounds due to surgical interventions;
• with burns or ulcers;
• who have long hospital stays, particularly in intensive care units;
• who received certain antibiotics for long periods of time, including vancomycin.

How are enterococcal infections diagnosed?

To correctly diagnose an infection caused by Enterococci, first of all your physician will perform a physical examination and ask you about symptoms and risk factors. Guided by these elements, your doctor will be able to choose the most appropriate diagnostic tests, and distinguish between enterococcal colonization and infection.

Laboratory tests can identify Enterococci using a sample taken from an area of the patient’s body likely to contain the microbe (for example, urine, blood or other tissue or fluid). These samples are sent to a laboratory to grow the microorganism over time using a media on a petri dish (culture) and identify it. Then susceptibility tests can be carried out to determine which antibiotics are most effective against it, to start the most appropriate antibiotic therapy.

Understanding which antibiotic will work best is especially key to vancomycin-resistant Enterococci (VRE) as these types of resistant Enterococci bacteria may only respond to certain medicines. In some cases, they may respond to none. Rapid novel molecular tests may assist physicians to choose appropriate antibiotics earlier.

Finally, depending on the type of infection, your physician may recommend additional tests, such as imaging tests.

How are enterococcal infections treated?

As Enterococci are bacteria, therapy is represented by antibiotics. The antibiotic may vary according to the type and severity of the infection, and the results of susceptibility tests. Indeed, some infections, such as those ones caused by vancomycin-resistant Enterococci (VRE), are resistant to several antibiotics.

Depending on the site and the severity of infection, the medication could be in the form of tablets to swallow. However, severe infections require treatment in hospital with intravenous antibiotics (i.e. the medication is given through a drip or a tube) and additional therapies.

Due to increasing resistance to the available medications, enterococcal infections are becoming more and more difficult to treat, and sometimes a combination therapy is needed (i.e. meaning that two or even three antibiotics are necessary).

How can enterococcal infections be prevented?

Following these precautions can lower your risk of getting an enterococcal infection. Moreover, they help to reduce your chances of spreading bacteria to others, as well.

• Wash your hands thoroughly and regularly with soap and running water. Then dry them with a clean towel, or a disposable paper towel. If you are not able to wash your hands, you can use an alcohol-based hand sanitizer. Keeping your hands clean is particularly important after using the bathroom, before and after caring for wounds or handling medical devices, and before preparing or eating food. Remember: hand hygiene is your best protection against infections.
• Frequently clean surfaces of the home, such as bathrooms, and use disinfecting products to clean, especially high-touch surfaces, for example your cell phone, doorknobs, bedside tables, and light switches.
• Wear gloves if your hands come into contact with body fluids, stool or bandages from infected wounds. Always wash your hands after removing gloves.

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