ESBL and carbapenemase-producing bacteria: a patient guide

Bacteria that live in the gut, notably Escherichia coli and Klebsiella pneumoniae, can acquire genes that produce enzymes capable of breaking antibiotics apart. An extended-spectrum beta-lactamase, or ESBL, defeats many commonly used penicillins and cephalosporins. A carbapenemase goes further and inactivates carbapenems, a class often reserved as the last line against serious infection. Laboratories may report these organisms as ESBL-producers, as carbapenemase-producing Enterobacterales, or by the shorthand CPE.

The same resistance genes can sit on small loops of DNA that bacteria pass to one another, which explains how resistance can appear in several different species within the same hospital.

The NHS describes antibiotic resistance as bacteria developing resistance to many different types of antibiotics, producing so-called superbugs, and warns that the biggest worry is new strains emerging that no existing antibiotic can treat. The World Health Organization reports that bacterial resistance was associated with over 4.7 million deaths worldwide in 2021 and that about one in six laboratory-confirmed bacterial infections were resistant in 2023.

For an individual, a resistant organism usually means fewer oral options, more reliance on intravenous drugs in hospital, a longer stay in some cases and a greater need for specialist microbiology advice. It does not mean every infection will be untreatable.

Resistant bowel bacteria are often found by chance on a screening swab, a urine culture or a blood culture. If they are only present in the gut and cause no symptoms, no treatment is needed. If they cause a urinary infection, wound infection, pneumonia or bloodstream infection, the laboratory tests which antibiotics still work and the clinician chooses accordingly.

Some hospitals screen patients for carbapenemase producers on admission, especially those who have recently been treated in hospitals abroad or who have been in contact with a known carrier. Screening is usually a rectal swab or stool sample. Staff may place a patient in a single room and use gloves and aprons while results are awaited.

Treatment is guided by laboratory sensitivity testing. Mild urinary infections caused by ESBL-producers may sometimes be managed with oral antibiotics to which the strain remains sensitive, while serious infections are normally treated in hospital with intravenous drugs, often carbapenems for ESBL and more specialised combinations for carbapenemase-producers. Doctors weigh the severity of illness, the site of infection and kidney function when selecting a regimen.

Removing or replacing infected devices, draining collections and supporting the patient with fluids and monitoring are as important as the drug choice.

Resistance is driven by antibiotic use, so personal habits count. The NHS advises following the prescriber, remembering that antibiotics do not treat viral infections, and accepting that they are not routinely prescribed for conditions such as sore throats and chest infections that are most often viral. The World Health Organization adds that antibiotics should be used only when prescribed, finished as directed and never shared.

• Clean your hands and ask visiting staff to do the same.

• Tell clinicians if you have previously carried a resistant organism, or have had hospital care abroad.

• Keep wounds, catheter sites and lines clean and report any new soreness or discharge.

• Do not ask for antibiotics for coughs and colds, and do not use old tablets.

Healthy household members are at very low risk. Good handwashing after using the toilet and before preparing food is the main precaution, with ordinary washing of clothes and bedding. People carrying resistant organisms can usually continue normal activities. If you are due an operation or admission, mention your carrier status so the team can plan antibiotic prophylaxis and bed arrangements sensibly.

Resistant infections can progress to sepsis. The NHS advises calling 999 for very fast breathing, confusion, severe shivering, mottled or blue skin, a non-blanching rash or not passing urine for a prolonged period. Children may become unusually sleepy, have seizures or feed poorly. If you are unsure, NHS 111 can advise.