Public transport in Latin America has the largest presence of resistant microbes

The analysis of bacteria, viruses and fungi present in urban transport systems and metropolitan railways in 58 cities around the world has found that the area with the highest prevalence of these antimicrobial resistant organisms (AMS) is Latin America. An international team of 600 researchers has taken 3,741 samples of railings, ticketing machines and subway station walls to create an "atlas" of urban communities of microorganisms.

Scientists used the samples to identify bacteria, viruses, and fungi as a whole, known as a microbiota, 2012, from these urban spaces and to study variations in genetic characteristics and antibiotic resistance


4,424 known species were identified in a total of 1,145 of which were detected in more than 70% of samples. 61 species present in more than 95% of samples are not part of the normal human microbiota that populates the skin and airways , nor the floor. The study, conducted by a consortium of scientists from Africa, America, Asia, Europe and Australasia, was published in BioRxiv, an open access repository for unprinted works that allows authors to make their findings available to the community scientifically immediately,

Eduardo Castro-Nallar, co-author of the paper and researcher of the Center for Bioinformatics and Integrative Bilogy of the Universidad Andrés Bello de Santiago de Chile, explains that "this has led to the idea that cities are an ecosystem in themselves, with a community stable microorganisms." In addition, the study found that more than 50% of the genetic samples collected could not be identified, meaning that there are microorganisms that science does not know or have not defined.

In Latin America, the researchers took samples of the metro and urban transport systems in Sao Paulo, Rio de Janeiro, Bogota and Santiago. The prevalence of RAM genes found in these environments was 10 to 20 times higher than that of cities in other parts of the world. Rio de Janeiro and Bogota, for example, had 10 times more RAM genes than Paris, Baltimore or Singapore.

The study also showed that the nature of RAM units and gene distribution varies between cities. "Although many microorganisms are present in many cities, there is a kind of microbial seal that identifies each of them. You could take a sample, analyze it, and guess where it came from," summarizes Castro-Nallar, who is also a researcher at the George Washington University Institute of Computational Biology


The study found that more than 50% of the genetic samples collected could not be identified, which means that there are microorganisms that science has not known or have not defined

"While some samples contain only a few RAM genes, in others there are in large numbers, which has repercussions not only for our knowledge of the development of cities, but also for urban planning," he says,

Scientists consider this to be a sign of the need to make better use of antibiotics in Latin America, adding: "The results of our article indicate that the prevalence of RAM genes is very high, surpassed only by Offa, in Nigeria.


Cristina Marino Buslje, researcher in the Structural Bioinformatics Unit of the Leloir Institute Foundation, in Buenos Aires, who did not participate in the work, believes that "it is an unprecedented study, possible thanks to the technical advances that allow build genetic sequence and computer analysis of huge amounts of data. "I hope that the government authorities will take into account the data generated by it when making health policy decisions. Work can also help healthcare professionals in diagnosing and treating infections," he says

Virgina Pasquinelli, of the National University of the Northwest of the Province of Buenos Aires, adds: "This work not only provides new information, but also provides free-use tools for the analysis of the urban microbiome. The ultimate goal is to build a database accessible to the entire scientific community that allows information to be reproduced and validated in different environments and to produce public health benefits.

"We know that the microbiome modulates the response of our immune system; even the response to tumors is regulated by the diversity of our normal flora. To think that this interacts with the urban microbiome is an interesting aspect to consider in future research", adds Pasquinelli.