Resistant and multiresistant bacteria

Treatment with antimicrobials is intended to kill pathogenic bacteria. Unfortunately, antimicrobials also cause the bacteria to protect themselves by developing resistance to the type of antimicrobials that are used to treat them. Bacteria that are resistant to several types of antimicrobials are sometimes referred to as multiresistant.

Facts about VRE

Vancomycin is the primary treatment for serious infections with antimicrobial resistant enterococci, but an increasing incidence of vancomycin-resistant enterococci (VRE) has been observed both in Denmark and internationally.

Many VRE are also resistant to other types of antimicrobials leaving few treatment options. 

Facts about ESBL

One of the few broad spectrum antimicrobials used in the treatment of life-threatening diseases is cephalosporin. What is particular to cephalosporin resistance is that the mechanism also causes the bacteria to become resistant to almost all common types of penicillin.

The enzymes that cause cephalosporin resistance are called ESBLs (extended spectrum beta-lactamases). Cephalosporin resistant bacteria such as E. coli, salmonella og klebsiella are therefore called ESBL-producing bacteria or simply ESBL-bacteria.

Facts about CPE

CPE stands for carbapenemase-producing Enterobacteriaceae. Enterobacteriaceae is the name of a large group of intestinal bacteria including E. coli. CPE bacteria are resistant to carbapenems.

Carbapenems are a group of antimicrobials which are used to treat serious infections with multiresistant ESBL-bacteria. In case of carbapenem resistance there are very few and often not optimal antimicrobials available to treat infections with this type of bacteria.

Facts about MRSA

MRSA (methichillin-resistant Staphylococcus aureus) is a staphylococcus bacteria, which is resistant to the types of antimicrobials commonly used to treat staphylococcus infections.

Traditionally MRSA-bacteria have been associated with infections that appear in hospitals and where serious infections, a prolonged illness and increased mortality ensue. However, in recent years MRSA has spread in society. Part of this spread is due to the type of bacteria known as MRSA CC398, which is found in pig production.

Facts about colistin

Colistin is not a new antimicrobial. It has had very limited usefulness in human medicine which for many years, whereas it has been used in animal production.

With the increasing occurrence of resistance to other antimicrobials in human bacteria, colistin is in some cases the only available option for treatment. Thus, its importance as a human drug has increased.

Resistance to colistin has so far been very low and mainly caused by mutations within the DNA-string, but in 2015 a gene was discovered that can transfer between types of bacteria.

Studies have since shown that it is widespread in bacteria especially from animals. The consequences for humans are still not known.


Frank Møller Aarestrup
Professor, Head of Research Group
National Food Institute
+45 35 88 62 81