Nightmare bacteria: 10 facts you need to know about CRE
Carbapenem-resistant Enterobacteriaceae (CRE) is a family of organisms (also described as nightmare bacteria) that are difficult to treat because they have high levels of resistance to antibiotics.
JOHANNESBURG – Following confirmation by the Gauteng Department of Health on Monday that 10 babies had died at the Tembisa Hospital in Ekurhuleni due to a Carbapenem-resistant Enterobacteriaceae (CRE) outbreak, questions have been raised over the nature of CRE infections and why babies would be vulnerable to them.
CRE is a family of organisms (also described as nightmare bacteria) that are difficult to treat because they have high levels of resistance to antibiotics. They can cause deadly infections in the bloodstream, lungs and urinary tract, including pneumonia and meningitis.
According to the Health Department, the CRE outbreak at the Tembisa Hospital’s neonatal unit was between November and December last year. It was suspected that the organism responsible for this outbreak was Klebsiella pneumonia, which are bacteria that normally live in the intestines and faeces.
Here’s what you need to know about CRE according to the National Institute of Communicable Diseases (NICD):
1. What are carbapenem-resistant bacteria?
Carbapenem–resistant bacteria are resistant to carbapenem (a class of antibiotic agents commonly used for the treatment of severe or high-risk bacterial infections) antibiotics. These bacteria are usually from the genera known as Klebsiella, Enterobacter, Escherichia, but other genera also become resistant to carbapenems. Bacteria are highly adaptive organisms.
Carbapenem antibiotics were introduced in the early 1980s and were seen as the last line of defence against Gram-negative bacteria (bacteria found everywhere that support life) that had become resistant to multiple other antibiotics. Examples of carbapenem antibiotics include imipenem, meropenem, ertapenem and doripenem.
Over time, Gram-negative bacteria developed resistance to carbapenem antibiotics. They have gained the ability to either break down carbapenems with an enzyme (“carbapenemases”) or to prevent the antibiotic from entering its cell or to transport it out of the cell. In this way, carbapenem antibiotics can no longer kill these bacteria. The problem is that now, infections with these Gram-negative bacteria are essentially untreatable.
2. What types of infections do carbapenem-resistant bacteria cause?
Organisms that are resistant to carbapenems can cause a variety of infections. Most commonly, they cause bladder infections, intra-abdominal infections, bacteraemia (when the bacterium infects the blood), pneumonia, and skin and soft tissue (including surgical site) infections.
Most of these infections are healthcare-associated but certain organisms may be introduced in community and cause infections in susceptible populations. Persons in nursing homes who have frequent admissions to hospital are at high risk.
3. Where do infections caused by carbapenem-resistant bacteria occur?
Bacteria resistant to carbapenems occur throughout the world in healthcare settings but seem to be more common in middle-income countries where access to antibiotics is common but usage of antibiotics is unrestricted. Infections caused by carbapenem-resistant bacteria occur across South Africa and their prevalence is increasing.
4. Who can get infections caused by carbapenem-resistant bacteria?
Healthy persons are usually not at risk for these infections. Persons who are at risk for infections with carbapenem-resistant organisms are those who have severe illness, surgical patients, long-term hospital-stay patients, persons undergoing organ or stem cell transplantation, persons in intensive care and those who are on mechanical ventilation. Although less common, persons can also be infected from the community.
5. How do infections caused by carbapenem-resistant bacteria spread?
Carbapenem–resistant bacteria can be spread from person-to-person through being touched by someone carrying the organisms on their hands, or when medical instruments (such as ventilators or urine catheters) or medications contaminated with the organisms are used.
Sometimes bacteria may transfer their genes that code for resistance to other bacteria. Sometimes resistant organisms can be newly created when antibiotics are overused.
6. What are the signs and symptoms of infections caused by carbapenem-resistant bacteria?
Clinical symptoms of infections caused by carbapenem-resistant bacteria are identical to symptoms caused by bacteria that are not resistant to carbapenem antibiotics and depend on the site of infection.
7. What are the complications of infections caused by carbapenem-resistant bacteria?
Persons with these infections are usually already weakened from other underlying conditions, so untreatable infections may lead to death in some cases.
8. How are infections caused by carbapenem-resistant bacteria diagnosed?
It is important to diagnose these infections early so that the best possible treatment can be given, and so that healthcare workers can observe strict infection prevention and control measures and prevent these infections from spreading to other persons.
9. How are infections caused by carbapenem-resistant bacteria treated?
A limited range of antibiotics can be used to treat infections caused by carbapenem-resistant bacteria. These include colistin, tigecycline and aminoglycosides. Unfortunately, these antibiotics are often not very potent (strong) and sometimes they have side effects. In most cases, combination treatment is recommended.
10. How can infections caused by carbapenem-resistant bacteria be prevented?
Careful use of antibiotics in hospital facilities is essential so that resistance to antibiotics does not develop, and so that the hospital environment does not “select” for resistant organisms. Infection prevention and control practices, including good hand hygiene, should be encouraged for all healthcare workers and patients.
Hospitals should set up systems to monitor the occurrence of healthcare-associated infections, including those caused by carbapenem-resistant bacteria.