What are extended-spectrum beta-lactamases (ESBL)?
There are at least 200 different types of ESBL enzymes. Researchers still have a lot to learn about them, in part because the infections involving ESBLs were only recently discovered.
The first reported case of infection involving ESBLs occurred in Greece in the 1960s. The United States reported its first case in 1988.
Many bacteria can develop resistance to antibiotics through random mutation.
So far, ESBLs have only been reported in Gram-negative bacterial infections. Gram-negative bacteria will appear pink during staining in preparation for microscopic examination.
Bacteria have built-in tools to trick the immune system and disable drugs. They can also develop drug-resistance through random mutation and pass on useful mutations to the next generation.
Several different species of bacteria are capable of producing ESBLs. Researchers are still unsure what triggers the bacteria to produce the drug-resisting enzymes, but misuse or overuse of antibiotics is suspected.
It is important to know that within each family and group of bacteria there are usually hundreds of different species, only some of which can produce ESBLs.
Bacterial groups known to produce ESBLs include:
- Escherichia coli (E.coli)
- Klebsiella pneumoniae
- Pseudomonas aeruginosa
- K. oxytoca
- Proteus mirabilis
- Salmonella enterica
- Neisseria gonorrhoeae
- Haemophilus influenzae
- Kluyvera species
- Enterobacter aerogenes
- Enterobacter cloacae
Thorough hand-washing can help prevent an infection.
Anyone who has contact with a surface, object, animal, or another person that is infected with or has been exposed to ESBL-producing bacteria can spread the infection.
Most ESBL infections, however, develop in healthcare settings and involve exposure to infected fecal matter.
According to a 2015 study, most people infected with ESBL-producing bacteria had been hospitalized for an average of between 11 and 64 days before developing the infection.
While traditionally associated with immune-compromised individuals, hospitals, and nursing homes, the infection is becoming more frequent and widespread.
According to the American Centers for Disease Control and Prevention (CDC), EBSL-producing bacteria are considered a serious threat in the U.S.
It is important to take extra precautions, including increased hand-washing, whenever exposure occurs or is suspected.
Many bacteria can live on the skin's surface for several days and even be transmitted through a person's breath. Some people who do not develop an infection or show symptoms can act as carriers, spreading the infectious bacteria without knowing it.
Associated conditions and symptoms
Bacterial infections involving ESBLs are known to cause several associated health conditions. Common complications and symptoms that accompany bacterial infections include:
Most ESBL-producing bacteria are called Enterobacteriaceae, a family of bacteria that normally lives in the gastrointestinal tract without causing infection.
For this reason, many ESBL-related infections irritate the gastrointestinal lining. When the body has an infection, the immune system also encourages increased metabolism and waste removal, causing diarrhea.
Common symptoms of diarrhea include:
- having three or more loose stools in one day
- bloody stool
- gas and bloating
- stomach cramps
- loss of appetite
Bacterial infections in wounds can cause the skin to become red and swollen. Fluid may also seep out of the wound site.
Several internal bacterial infections can also cause dermatological symptoms, including red, raised bumps.
Pneumonia occurs when bacteria infect the lungs and respiratory tract. Common symptoms of pneumonia include:
- coughing, often with phlegm or thick mucous
- difficulty breathing
- fatigue or unexplained exhaustion
- shortness of breath
- fever and chills
- sweating and shaking
- nausea and vomiting
- low body temperature
Urinary tract infections
Urinary tract infections (UTIs) occur when bacteria overgrowths develop in the urinary tract. Common symptoms of UTIs include:
- increased need to urinate
- burning sensation during urination
- itching, burning sensation in the genital region
Sepsis occurs when an infection causes the immune system to overreact, releasing chemicals into the bloodstream that trigger a full-body inflammatory response. Sepsis is life-threatening and can lead to organ failure and death.
Common symptoms of sepsis include:
- fever and chills
- nausea and vomiting
- feeling disorientated and confused
- difficulty breathing
Treatment and outlook
As ESBL-producing bacteria are resistant to common antibiotics, treatment involves using less common medications, which can sometimes be less effective.
Also, many ESBL-producing bacteria have additional tools to disable other types of antibiotics. If a person has had the infection long-term, or when medications are overused, bacteria can evolve and develop immunity to them.
The first line of treatment for people who have been confirmed as having the infection is usually a class of drugs called carbapenems. The treatment process may involve some degree of trial and error.
It may take several courses of treatment and different medications to resolve a person's infection completely.
Commonly used medications to treat ESBL-involved infections include:
- carbapenems (imipenem, meropenem, and doripenem)
- cephamycins (cefoxitin and cefotetan)
- beta-lactamase inhibitors (clavulanic acid, tazobactam, or sulbactam)
- colistin, if all other medications have failed
According to the CDC, carbapenem-resistant Enterobacteriaceae are a very serious developing threat.
Carbapenem-resistant infections are immune to nearly every form of antibiotic available and are responsible for 9,000 infections per year and 600 deaths. Almost half of the people who developed the infection in their bloodstream died.
In some situations, especially if a person has a weakened immune system, hospitalization and isolation may be necessary. Most infections take several weeks or months to treat.
Preventing ESBL-involved bacterial infections may include avoiding touching the face and mouth, disinfecting surfaces, and wearing gloves in a healthcare setting.
People with long-term conditions and people who are hospitalized are the most at-risk of developing ESBL-involved infections. Extra precautions, such as increased hand washing, should always be used in healthcare settings.
General tips for preventing ESBL-involved bacterial infections include:
- avoiding close contact with people or animals with bacterial infections
- wearing gloves in healthcare settings or around infected individuals
- avoiding touching the face and mouth
- wearing long-sleeved clothing when around infected individuals
- washing hands before and after exposure to infected individuals
- washing all clothing and bedding that may have been exposed to infected individuals in hot water
- disinfecting surfaces, especially in bathrooms and kitchens
- disinfecting fixtures, such as doorknobs and faucets
- taking antibiotics exactly as directed
- telling a doctor if antibiotics are not improving symptoms of an infection
- talking with a doctor and taking extra hygiene precautions if several courses of antibiotics are necessary within a short timespan
- if an ESBL-involved infection is confirmed, avoiding exposure to others or being in public settings, especially crowded areas