Petting zoos may transmit highly virulent pathogens to vistors, finds study

Zoos have always fascinated people! But a new study reveals that petting zoos could be adverse, as they create a reservoir of multidrug-resistant (MDR) bacteria, which leads to highly virulent pathogens to be passed on to the visitors.

The study was presented in the meeting ECCMID 2019.

"Our findings demonstrate that animals in zoos can result in shedding and transmission of MDR pathogens that may cause illness for human visitors, even when the animals appear healthy," said Navon Venezia.

Extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacteriaceae (AmpC-E), which are resistant to a number of commonly used antibiotics, have become a matter of great concern in both human and veterinary medicine, so understanding the likelihood of them colonising the animals is critical to evaluating the risk that may be posed to visitors.

The researchers chose 8 random zoos and took samples from 228 animals belonging from 42 different species. The samples were taken from the faecal matter as well as from the body surface (skin, fur, or feathers).

Genetic sequencing was used to identify both the species of bacteria in each sample and the presence of ESBL and AmpC drug resistance genes. Zoo owners were given questionnaires about the ages and medical histories of their animals which were analysed to determine additional risk factors.

A total of 382 samples were collected from 228 animals. 12 per cent of the animals were found to be colonised with at least one ESBL/AmpC-producing bacterial strain with 35 different recovered species of bacteria.

The majority (77%) of the MDR bacteria were obtained from faeces, with the remaining 23% coming from skin, fur, or feathers. A quarter of those animals which tested positive for drug-resistant bacteria were colonised by more than one bacterial strain.

Analysis of the data revealed that if an animal was treated with antibiotics it was seven times more likely to shed MDR bacteria. The study found that petting zoos provide a reservoir for a diverse range of ESBL/AmpC-E species, and are a potential source for shedding these highly virulent pathogens that may be transmitted to humans.

Navon said, "We strongly recommend that petting zoo management teams implement a strict hygiene and infection control policy, together with rationalised antibiotic policy, in order to reduce the risk of transmission between animals and visitors."

"Immediate actions by zoo operators should include installation of hand washing stations to ensure proper hand washing before and after petting animals, prohibiting food and drinking near animals, and also not allowing petting of animals receiving antibiotic treatment," she concluded.