ESBL bacteria are a group of germs that resist many common antibiotics. They produce enzymes that break down and disable certain antibiotic medications, making them ineffective. This resistance makes ESBL infections more challenging to treat than those caused by non-resistant bacteria. Their presence is a concern within healthcare settings.
The Science of ESBL Bacteria
The term “Extended-Spectrum Beta-Lactamase” describes the enzyme produced by these bacteria. Beta-lactamase breaks down a specific part of certain antibiotics, the beta-lactam ring, rendering the antibiotic ineffective. The “extended-spectrum” aspect means this enzyme can disable a wide variety of beta-lactam antibiotics, including penicillins and many cephalosporins, which are commonly used to treat bacterial infections.
Common ESBL-producing bacteria include Escherichia coli (E. coli) and Klebsiella pneumoniae, though other types can also develop this resistance. These bacteria may naturally reside in the human gut without causing harm.
Understanding the difference between colonization and infection is important. Colonization means the bacteria are present on or in the body, such as in the gut or on the skin, but are not causing illness or symptoms. An infection occurs when the bacteria multiply and damage body tissues, leading to disease symptoms. A person can be colonized with ESBL bacteria without developing an infection, but they may still spread the bacteria to others.
Transmission and Risk Factors
ESBL bacteria primarily spread through direct or indirect contact. This often occurs in healthcare environments like hospitals and long-term care facilities. Transmission can happen when healthcare workers or visitors touch contaminated surfaces or equipment and then touch other people without proper handwashing. It can also spread directly from person to person through contact with an infected or colonized individual.
Several factors increase the likelihood of acquiring ESBL bacteria. These include prolonged or frequent stays in a hospital or long-term care facility due to increased exposure. Receiving extended courses of antibiotics, particularly broad-spectrum types, can disrupt the body’s natural bacterial balance and promote the growth of resistant strains. The presence of invasive medical devices, such as urinary catheters, intravenous lines, or ventilators, also provides pathways for bacteria to enter the body.
Individuals with weakened immune systems are more susceptible to acquiring and developing infections from these bacteria. While less common, ESBL bacteria can also be acquired outside of healthcare settings.
Symptoms and Diagnosis
Infections caused by ESBL bacteria do not present with unique symptoms that differentiate them from other bacterial infections. Instead, symptoms depend on the infection’s location. For instance, a urinary tract ESBL infection might cause painful urination, frequent urges to urinate, or fever. If the bacteria enter the bloodstream, it can lead to a bloodstream infection with symptoms like high fever, chills, and confusion.
Similarly, an ESBL infection in the lungs would present with symptoms characteristic of pneumonia, such as cough, shortness of breath, and chest pain. The challenge with ESBL infections is not unusual symptoms, but the difficulty in treating them due to antibiotic resistance.
The diagnostic process begins when a healthcare provider suspects a bacterial infection. A sample is collected from the suspected site, such as urine, blood, sputum, or a wound swab. This sample is sent to a laboratory for culturing. Once the bacteria multiply, technicians perform tests to identify the type of bacteria and determine which antibiotics are effective. This antibiotic susceptibility testing reveals if the bacteria produce ESBL enzymes, guiding treatment decisions.
Treatment and Management
Treating infections caused by ESBL bacteria is challenging because many common antibiotics are ineffective. ESBLs render a broad range of beta-lactam antibiotics, including most penicillins and cephalosporins, unable to kill the bacteria. Healthcare providers must select alternative antibiotic classes not affected by the ESBL enzyme.
Carbapenems, such as meropenem or imipenem, are often used to treat severe ESBL infections. These medications are frequently administered intravenously and often require hospitalization for monitoring and administration. The specific antibiotic chosen depends on the results of antibiotic susceptibility tests.
In addition to antibiotic therapy, infection control measures are implemented to prevent the spread of ESBL bacteria, particularly in healthcare settings. These measures include strict hand hygiene, where healthcare workers wash their hands or use alcohol-based sanitizers before and after patient contact. Patients known to be infected or colonized with ESBL bacteria may be placed under contact precautions, requiring staff to wear gloves and gowns when entering their room. Environmental cleaning and disinfection of patient rooms and equipment also play a role in reducing transmission.