Multidrug-resistant germs are common in urban rats

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Vienna – People are not the only creatures that can be infected with multidrug-resistant bacteria. A study in euro surveillance (2019, doi: 10.2807 / 1560-7917.ES.2019.24.32.1900149) have shown that dangerous germs are also prevalent in urban rats.

Rats like to stay close to people. They feed on their waste, which they often track down in the sewers. They can also detect pathogens. The rats are therefore of interest to researchers studying the distribution of multidrug-resistant bacteria.

Amelie Desvars-Larrive of the University of Veterinary Medicine of Vienna and her colleagues examined 62 specimens of the brown rat (Rattus norvegicus), which they had captured at Karlsplatz and on the Danube Promenade. Karlsplatz is one of the tourist centers of the Austrian capital and its walks are popular with homeless people.

The researchers found that most of the rats were colonized with multidrug-resistant bacteria. In 9 of 62 rats, eight multidrug-resistant Escherichia coli and two Enterobacter with dread resistance to NDM-1 were found, against which many antibiotics remain ineffective. 9 Enterobacteriaceae isolates contained the CTX-M gene, 1 the ampC gene. Both also confer resistance to beta-lactam antibiotics. Methicillin-resistant staphylococcal species were isolated from 37 rats.

Urban rats thus potentially become carriers of pathogens. The most vulnerable are the homeless, who have a much closer contact with rodents than tourists, provided that the places visited are cleaned regularly. We do not know if and how often infections are.

Incidentally, Vienna is not the only city where rats are infected with multidrug-resistant enterobacteria. The incidence in this study (14.5%) was comparable to that of previous surveys in Berlin (13.6%) and Hong Kong (13.9%). In Piraeus, the incidence was even 61.5%, against "only" 6.5% in Vancouver. © heat / Good medical