Extended-Spectrum Beta-Lactamase (ESBL) producing E. coli Frequently Asked Questions

What is E. coli?
E. coli are very common bacteria that normally live harmlessly in the gut. E. coli are also one of the most common bacteria that cause infections in humans. The most common infections caused by E. coli are urinary tract (“kidney”) infections (UTIs), which includes cystitis. Most urinary tract infections get better without treatment, or are easily treated with antibiotics. However, these infections can sometimes progress to cause more serious infections such as bloodstream infection (otherwise known as bacteraemia or “blood poisoning”) which can be life threatening.

What is ESBL-producing E. coli?
ESBLs (Extended-Spectrum Beta-Lactamases) are enzymes produced by some types of bacteria, including some strains of E. coli, that make these bacteria resistant to most beta-lactam antibiotics (such as penicillins and cephalosporins). ESBL-producing E. coli and other bacteria may also be resistant to other classes of antibiotics, including fluoroquinolones (e.g. ciprofloxacin), aminoglycosides (e.g. gentamicin), tetracyclines and trimethoprim. They are therefore more resistant to antibiotics and  so the infections that they cause are harder to treat.

Most people who carry ESBL-producing E. coli carry it harmlessly without any ill effects – This is called Colonisation.

What illnesses do ESBL-producing E. coli cause?
ESBL-producing E. coli cause the same types of infections as other strains of E. coli. When ESBL-producing strains of E. coli do cause infections, they are more difficult to treat, because of their antibiotic resistance.  

Are some people more at risk than others?
Infections caused by ESBL-producing E. coli usually happen in people with other underlying medical conditions who are already very sick, such as patients in intensive care units, and elderly people. Most infections occur in patients who have been taking antibiotics or who have been previously hospitalised. 

Is this the type of E. coli that causes severe food poisoning?
No. There are very specific and distinct strains of E. coli, such as E. coli O157, which cause food poisoning. ESBL-producing E. coli are are not  linked with food poisoning.  

How do people get it?
People colonised or infected with ESBL-producing E. coli are usually in hospitals, particularly in intesive care units, and usually have underlying medical conditions (for example, a chronic illness such as diabetes) or who have taken a lot of antibiotics. ESBL-producing E. coli can be spread from patient to patient on the hands of healthcare workers or from the hospital environment.
ESBL-producing E. coli can sometimes be contracted in the community, possibly through contaminated food or water, but more research is needed to find out how often this happens.

Is it treatable?
Yes, infections caused by ESBL-producing E. coli can be treated with antibiotics, but the choice of antibiotics is limited because these bacteria are resistant to many commonly-used antibiotics. Therefore it is important that these infections are diagnosed quickly, so that the best treatment can be given.  

How many infections caused by ESBL-producing E. coli occur in Ireland each year?
The Health Protection Surveillance Centre (HPSC) collects information on bloodstream infections (“blood poisoning”) caused by a variety of different bacteria, including E. coli.

In 2004, there were 1,256 cases of E. coli bloodstream infections reported from 41 laboratories. Of these, 861 were tested for ESBL and 11 (1.3%) were found to be ESBL-producing E. coli.
In 2005 there were 1,445 cases of E. coli bloodstream infection reported from 42 laboratories. Of these, 1,144 were tested for ESBL and 30 (2.6%) were found to be ESBL-producing E. coli.

At present, we do not have national data for other infections, such as urinary tract infections, caused by ESBL-producing E. coli. However, there have been reports of urinary tract infections caused ESBL-producing E.coli. The strain causing these infections appears to be similar to a strain of ESBL-producing E. coli that has become more common in the UK and other European countries in recent years. Further investigations are needed to find out how widespread these and other ESBLs are in Ireland.

How can the spread be controlled?
Good hand hygiene and environmental cleaning in hospitals reduce the risk of ESBL-producing E. coli being spread from patient to patient. It is also important to make sure  that antibiotics are prescribed only when needed, in the right dose, for the right duration, to reduce the chances of bacteria becoming resistant  .

Other infection control precautions may be taken when a hospital patient is  colonised or infected with ESBL-producing E. coli, such as nursing a patient in a single room. Some hospitals routinely take swabs from “high risk” patients (for example, patients in the intensive care unit) to identify if someone is carrying ESBL-producing E. coli, or similar resistant bacteria.

Do other bacteria produce ESBLs?
Yes. ESBLs can be produced by other bacteria, such as Klebsiella pneumoniae and Pseudomonas aeruginosa. Many of these bacteria tend to be closely associated with hospitals and so generally only cause infections in people with serious underlying medical conditions. The treament and control of infections caused by these types of bacteria is similar to that for ESBL-producing E. coli.