NDM (New Delhi metallo-β-lactamase) enzyme-producing E. coli and other bacteria resistant to carbapenem antibiotics

What are carbapenems?

Carbapenems are broad-spectrum antibiotics. They are one of the last-resort options used for the treatment of human infections caused by multi-drug-resistant bacteria. Carbapenems have not been registered as veterinary drugs. Their use for animals is prohibited in Finland.

What is NDM?

The New Delhi metallo-β-lactamase (NDM) is one of the enzymes able to degrade carbapenems. It was named after the first case – a Swedish patient had been treated in hospital in New Delhi. After repatriation to Sweden, an NDM-producing strain of Klebsiella was detected in the patient’s urine. NDM-producing bacteria are resistant to carbapenems and often also to all other known groups of antibiotics. Intestinal bacteria such as E. coli, Klebsiella pneumoniae and Salmonella can produce NDM. Other bacterial genera reported to produce the enzyme are Acinetobacter and Pseudomonas.

What do NDM-producing bacteria cause?

Although NDM-producing bacteria can degrade broad-spectrum antibiotics, the production of NDM or other carbapenemases does not increase their ability to cause diseases. They are not harmful to healthy people, and colonisation is often asymptomatic. If colonisation results in an infection, its treatment is difficult as these bacteria are highly resistant to almost all known antibiotics.

In which animals have NDM-producing bacteria been found?

So far, NDM-positive bacteria have very rarely been found in animals. NDM-producing E. coli bacteria have been detected in dogs and cats in the United States. They mainly originated from urinary tract infections or wound and nasal secretions. NDM-producing Acinetobacter has been isolated from broiler chicken and swine samples in China, and NDM-positive Salmonella Corvallis from a black kite in Germany. In Italy, NDM-producing Acinetobacter was found in the faeces in 0.8% of all dogs treated in veterinary hospitals. The actual occurrence of NDM-producing and other carbapenem-degrading bacteria in animals is unknown.

Have carbapenem-resistant bacteria been found in animals in Finland?

NDM-positive E. coli was isolated from an ear sample taken from a dog in spring 2015. It was also found in another dog; the two dogs were in contact with each other. No carbapenem-resistant bacteria have been found in Finnish production animals.

Can NDM-producing bacteria be transmitted between humans and animals?

NDM-producing bacteria are being increasingly detected in humans on all continents. People often live in close contact with their pets, and thus the transmission of bacteria between humans and animals is possible. In Finland, NDM-producing bacteria have been found in humans on several occasions in recent years, while the first case in animals was reported in 2015. More information (in Finnish) on carbapenem-resistant bacteria found in humans in Finland is available on the website of the National Institute for Health and Welfare (THL).

Can the spread of NDM-producing bacteria be prevented?

As antibiotics favour the survival and spread of resistant bacteria in humans and animals, the use of antibiotics for treatment must always be justified. The use of the most broad-spectrum antibiotics and especially carbapenems for the treatment of animals is prohibited in Finland.