La Jornada: Dangerous bacteria for humans, present in dogs, horses and wastewater

A team of researchers from the Center for Genomic Sciences of the National Autonomous University of Mexico (UNAM) revealed that Acinetobacter baumanniione of the most dangerous hospital bacteria for humans due to its high resistance to multiple antibiotics, is present in dogs, horses, sewage and other non-human sources.

The research, published in the journal Nature Communicationsrethinks the way of understanding the pathogen, since while previous studies had focused their attention on clinical settings, this one managed to map its presence outside of hospitals.

“Under the One Health approach, which considers human health interconnected with animal and environmental health, we decided to undertake this project from a multidisciplinary approach,” says Santiago Castillo Ramírez, an expert in evolutionary and population genomics of pathogenic bacteria and who heads the study.

In interview with The Day details that they analyzed more than 23 thousand genomes of A. baumanniiof which one thousand came from 95 non-human sources, including white herons, pork, salmon and coconut pulp. The most difficult part of the analysis process, he explains, was curating the data.

“We reduced from 34 thousand to 23 thousand records, after data cleaning, when we were left with only those that allowed us to make reliable inferences.”

One of the most surprising findings was that there were so many different sources of A. baumanniibecause “we thought it was going to be less than 40,” explains the researcher.

Another revealing fact is that the diversity analysis of the genomes identified that the non-human samples, all of them together, are more diverse than the populations from humans.

Regarding the ability to resist antibiotics, they found that most animal or environmental reservoirs have fewer resistance genes than bacteria found in hospitals and humans. However, they found exceptions in dogs and wastewater, whose resistance levels are similar to those detected in humans and also contain genes of clinical relevance.

Castillo Ramírez considers that the data obtained in this analysis is of great importance for public health because “until now it is not known whether animal or environmental reservoirs can transmit infections to humans. We must evaluate how pathogenic they can be.”

The scientist stated that after the publication of this article, the team plans to undertake more specific studies to delve deeper into the dynamics of transmission.

“So far we have anecdotal cases, that is, for example the owner of a pet. There, our work suggests the transmission processes, but it is necessary to develop more specific projects to understand the dissemination in greater detail.”

He explains that it is also relevant to understand the directions of transmissions, “since cats and dogs can transmit it to humans, but we can also transmit it to them. There are interesting things that still need to be understood,” he points out.

One of the projects that Castillo Ramírez is most excited about is the one he will carry out with his colleague Carlos Méndez, from the UNAM CCG, through the use of artificial intelligence. They plan to develop models that allow them to identify the origin of the bacteria and determine whether it comes from a hospital or non-human environment, such as a river.

They also want to evaluate genes related to virulence to determine their ability to cause an infection or not.

“If we want to understand the biology of these pathogens we need to go beyond our anthropocentric biases and stop studying them only in hospitals or in humans. Their biological complexity is much greater than we imagine.”