Host-changing super-germs Cows increasingly carriers multiresistant MRSA bacteria

MRSA bacteria are increasingly transmitted by cattle

Cattle appear to be carriers of resistant MRSA bacteria. Genetic analyzes show that the pathogens have infested not only humans, but also livestock for millennia - and repeatedly jump back and forth between different hosts. The host changes allow the bacteria by genetic changes new antibiotic resistance. The result is particularly hard to kill "super germs".

contents

• MRSA bacteria are increasingly transmitted by cattle
• Man as the original host
• Cows as the main source
• Identify early

Many bacterial pathogens can not be controlled by antibiotics - they have built up a resistance. Particularly feared among the antibiotic-resistant bacteria is the methicillin-resistant Staphylococcus aureus, MRSA for short. The bacterium is mainly known as a hospital germ. "It is spreading in clinics around the world," says Jukka Corander of the University of Helsinki. The pathogen can also appear in everyday life, theoretically nest in every household and infest our pets and pets. The scientists published their results in the journal Nature Ecology & Evolution.

Man as the original host

Despite its dangerousness, little is known about the genesis and development of the MRSA pathogen. To gain more basic insights, Corander and his colleagues have now studied numerous human and animal MRSA samples. They looked for DNA changes in the genome of the bacteria that indicate an adaptation to new hosts.

The result: Originally, the MRSA bacterium probably only affected us humans. The ability to nest in other species, according to genetic analysis, only acquired after the so-called Neolithic revolution - when humans began to domesticate animals and keep them in larger herds on farms.

Cows as the main source

From this moment, certain strains of bacteria have repeatedly changed the host, according to the scientists. Accordingly, the bacteria regularly jump from livestock to humans and vice versa. Such host changes are often accompanied by genetic mutations that help bacteria survive in the new environment in the long term - bacterial evolution!

Among other things, the pathogens can also acquire antibiotic resistance - and eventually become multi-resistant "super germs". Cows seem to be at particular risk: they are an important source of pathogens and the main source of multidrug-resistant Staphylococcus strains that cause dangerous MRSA infections in humans.

Identify early

"This observation highlights the importance of nationwide monitoring to identify potentially epidemic-causing strains early," says Corander. He and his colleagues hope that their research will help to minimize the risk of host changes to new MRSA strains of animals in the human population. (Fs)