Mauricio Corredor

By Pablo Valderrama-Carmona, Jaison H. Cuartas, Diana Carolina Castaño and Mauricio Corredor

Methyltransferases play a fundamental role in aminoglycoside resistance of Gram-negative bacteria, and some of its mechanisms were described in the past years, especially in Escherichia coli; however, it remains unsolved for other resistant bacteria such as Pseudomonas aeruginosa. Despite hurdles to determine resistance acquisition, high-throughput approaches (genomics, transcriptomics, and proteomics) have allowed data mining and analysis in a systemic way. Likewise, bioinformatics modelling of homologous genes or proteins has permitted to elucidate the emerging resistance in this pathogen. P. aeruginosa is a bacterial resistance treat since practically all known resistance mechanisms can be described using this model, particularly RNA methyltransferases. The RNA methyltransferases perform methylation or demethylation of ribosomal RNA to allow or restrict the antibiotic resistance development. The Kgm and Kam methyltransferases families are found in P. aeruginosa and confer resistance to several aminoglycosides. Loss of native methylations may also confer a resistant phenotype. The P. aeruginosa RsmG has high structural homology with Thermus aquaticus protein. Today, molecular data will promote a new paradigm on antibiotic therapy for treatment against P. aeruginosa. This chapter provides an overview of what role P. aeruginosa’s methyltransferases play in antibiotic resistance, induced by methylation or demethylation in the ribosome.

Part of the book: Pseudomonas Aeruginosa

By Mauricio Corredor and Amalia Muñoz-Gómez

Antibiotics were the world’s great therapeutic hope after the Second World War, but today, unmonitored use has become one of the greatest risks for humanity. Without overestimation, one of the last scientific books on antibiotics was entitled: Antibiotics, the perfect storm. Before to environmental contamination by antibiotics, the pathogens got resistant to them. Because of the radical changes that antibiotics have brought about, they can generate new resistant bacteria in the environment that were previously harmless. These microorganisms will be exposed to concentrations of antibiotics never reached or will be exposed to unknown molecules that, for many of them, in certain environments, have never been exposed before. Initially, many of these antibiotics did not penetrate soils with high agricultural production, but in the following decades, they were even interspersed into crops. Nowadays, hundreds of tons of antibiotics are dumped into rivers and the sea. Many hospitals have water treatment facilities to prevent significant contamination, but not all companies, farms, and hospitals in developed, emerging, or poor countries apply wastewater treatment. Antibiotics are incorporated into wild microorganisms and plants, triggering a broad “unnatural” resistance, which will rapidly incorporate this information into the genome of other pathogenic microorganisms by horizontal transfer. On the other hand, antibiotics could be incorporated into drinking water and water intended for human or agricultural consumption that travels without being detected or monitored. This review covers the most important aspects of environmental pollution by antibiotics.

Part of the book: Emerging Contaminants