What Is Carbapenem-Resistant Infection?
CRE (carbapenem-resistant Enterobacteriaceae) infections are caused by bacteria found as a commensal in a healthy person's digestive tract. When a person receives serious medical care such as intravenous catheters, urinary catheters, or surgery, these bacteria can end up in places they do not belong, such as the bladder or blood. Because these bacteria have developed antibiotic resistance, these infections are extremely difficult to treat. Carbapenem-resistant Enterobacteriaceae (CRE) are bacteria strains resistant to an antibiotic class, Carbapenem, used to treat severe infections. CRE is also resistant to the majority of other commonly used antibiotics and, in some cases, to all antibiotics.
Antibiotic Resistance Mechanism - Antibiotic resistance is a growing issue, especially in carbapenemase-producing Enterobacteriaceae (CRE). Resistance genes exist for all antibiotics currently in use, and extremely resistant pathogens are becoming more common. Gram-negative bacteria have developed the broadest spectrum of resistance due to multiple structural adaptations and antibiotic degradation enzymes, such as expanded spectrum beta-lactamases (ESBL), cephalosporinases, and carbapenemases. In addition, the mechanism behind the antibiotic resistance for carbapenam are:
- Enzyme production.
- Porin (channels present over the outer membrane of the bacteria) mutation.
- Efflux pumps (the gram-negative bacteria let out the substance [for example medications] that are toxic to them).
Pharmacology - Carbapenems are structurally similar to penicillins but have an additional carbapenem ring. Both antibiotics use a beta-lactam ring to degrade the bacterial cell wall at the penicillin-binding protein. These antibiotics' carbapenem groups protect the beta-lactam ring from bacterial regulatory enzymes.
When diagnosing, treating, and preventing CRE infections, caution is required. Bacteria may have multiple carbapenem resistance mechanisms, but carbapenemase enzyme production is most common. These carbapenemase-producing carbapenem-resistant Enterobacteriaceae (cpCRE) degrade antibiotics using a variety of moieties. Other resistance mechanisms rendering the antibiotics ineffective include specific porin blocking at the bacterial cell membrane to limit antibiotic permeability and increased efflux pump activity.
Who Is the Population at Risk?
If a patient is admitted to the hospital and requires assistance with bathing and other daily activities, requires devices such as breathing machines (ventilators) or catheters, or has serious illnesses, the risk of CRE infections may be increased. Long courses of certain antibiotics can also increase the risk. CRE infections are associated with a high mortality rate. Infections caused by CRE have frequently caused outbreaks in health care settings.
Other organisms resistant to carbapenam are as follows:
- Pseudomonas aeruginosa - Respiratory infections, dermatitis, urinary tract infections, joint infections, etc.
- Acinetobacter baumannii - Blood infections, lung and urinary tract infections.
- Klebsiella pneumoniae - Lung infections.
What Are the Symptoms of CRE Infections?
The CRE infection symptoms vary. They may vary depending on the type of bacteria involved and the part of the body infected. Klebsiella pneumonia is one example. It is a bacteria that is frequently resistant to carbapenems. Infection with these bacteria may cause the following symptoms:
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Breathing difficulty (from pneumonia).
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Urinary discomfort (from urinary tract infection).
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Skin inflammation and pain (from skin infection).
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Pain in the abdomen (from liver or splenic infection).
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Reduced consciousness and stiff neck (from meningitis infection).
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Fever, chills, and exhaustion (from infection in any location).
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Other types of CRE infections may cause different symptoms.
Is It Possible to Avoid CRE Infection?
In a hospital setting, the following can be performed to prevent the spread of CRE:
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In healthcare facilities, CRE infections must be closely monitored.
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Taking precautions to keep CRE patients isolated.
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As soon as possible, remove any medical devices inside the body, such as catheters.
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Antibiotics (particularly carbapenems) should only be prescribed when necessary.
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To reduce the spread of infection, use clean (sterile) techniques.
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Always use standard infection-control methods, such as thorough handwashing.
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If you are in the hospital, spend as little time as possible in the intensive care unit.
You can also aid in the prevention of CRE infection by doing the following:
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Take your antibiotics exactly as directed. Do so even if you are feeling better. It will aid in the prevention of bacteria like CRE.
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Remind your healthcare team to remove potential sources of infection, such as catheters, as soon as possible.
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Always maintain proper hygiene. Hands should be washed frequently.
How Is CRE Infection Diagnosed?
Blood cultures are used to diagnose CRE (and other antibiotic-resistant superbugs). These blood cultures contain the bacteria that cause infection. A drug sensitivity test is performed to determine whether the organism is antibiotic-resistant (modified Hodge test). An antibiotic-resistant superbug is one whose growth is not significantly slowed by a combination of antibiotics, one of which is carbapenem. The Hodge test is a simple test that detects CRE bacteria growth in the presence of carbapenem. PCR (polymerase chain reaction) tests to determine the type of bacterium that is infecting the individual may also be performed. The healthcare provider will begin by asking the patient about his medical history. Next, they will inquire about the symptoms and any previous health issues. The patient will almost certainly require a physical examination as well. The doctor will determine the tests based on your symptoms and clinical examination. They could include:
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A complete blood count (CBC) to check for anemia and infection.
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Chest X-ray to rule out lung infection.
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Urine tests to detect urinary infection.
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If additional imaging tests are required, they will be performed.
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Blood, urine, sputum, and other bodily fluid cultures.
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Antibiotic susceptibility tests.
What Is the Treatment for CRE Infection?
The treatment you receive will be determined by your symptoms, age, and overall health. It will also depend on the severity of the condition. The treatment may consist of the following:
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Monitoring vital signs such as heart rate with care.
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Anti-fever medications.
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Intravenous fluids.
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Nutritional assistance.
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Treatment of any other medical conditions you may have.
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If necessary, a ventilator.
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Other antibiotic therapy.
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In extremely rare cases, there may be no other antibiotic that works. Supportive care may assist you in fighting the infection.
Antibiotics such as Aminoglycosides, Tigecycline, Polymyxin, Temocillin, and Fosfomycin have been used to treat CRE infections with some success. Clinicians sometimes refer to these as "last resort" drugs because they may be the only drugs available to effectively treat patients with CRE infections. Infectious disease specialists should be consulted if a person is diagnosed with a CRE infection.
Conclusion:
CRE infections generally show a prognosis ranging from fair to poor. If the infection is detected early and treated appropriately, the prognosis is favorable; however, if the CRE bacteria enter the bloodstream, 40 percent to 50 percent of infected patients die. Humans face plenty of dangerous microbial foes, and researchers and medical professionals believe CRE bacteria are just the beginning. The CDC advises healthcare workers on reducing or preventing a large-scale outbreak of CRE bacteria. UCLA has provided free home-testing kits that can be analyzed at the hospital in an effort to determine who may have been exposed to CRE bacteria.
