**Author details**

*Pseudomonas aeruginosa - An Armory Within*

**6. Final considerations**

the global environment.

**Acknowledgements**

Jaison H. Cuartas, project CODI 2017-15753.

very important for antibiotic resistance, thanks to the similarity of these enzymes with those homologs found in aminoglycoside-producing actinomycetes [6]. Those new genes and proteins will be better studied in expression and structure, to be related to epidemiological data. Looking at **Table 2**, it seems that the expression of methyltransferase might be related to geographical prescription. However, this hypothesis does not seem well founded: microbiological, molecular, and epidemiological understanding of RNA methyltransferases in *P. aeruginosa* will allow the rational

use of aminoglycosides and maybe will be not replaced for new antibiotics.

Antibiotic resistance is a serious concern for public health and environment. To comprehend the molecular interaction of the methyltransferase in aminoglycoside resistance will be a more efficient way to rationalize its use and consumption. It will be better to clarify the panorama of the rational use of the aminoglycosides to diminish the rapid development of resistance before considering its replacement, since *P. aeruginosa* is still susceptible to them, and, moreover, currently it is known why other *Gammaproteobacteria* are resistant to them. Why are methylation and demethylation a feedback of the antibiotic environmental pressure in bacteria? Bhujbalrao and Anand [64] suggest us some insights using KsgA, exploring the factors which govern the resistance to antibiotics. They observed within loop1 and loop12 of rRNA switched chimera efficiently methylated mini-RNA substrates in vitro, showing that these structural elements suffice for local orientation of the rRNA. In addition, in vivo they notice that the head domain plays a more critical role in leading the enzyme to the select ribosomal region and serves as a sensor of

As Kim et al. [65] discuss in letter to editor (Dr. Hur), investigating with P. aeruginosa and aminoglycoside resistance proposes that "less aminoglycoside consumption correlates with less resistance levels"; therefore, we consider that is a requisite for an antibiotic cycling strategy at the global level; also they discussed the rates of amikacin or gentamicin-resistant declining trends, according to the data from KONSAR Korean program in 2011 either for *P. aeruginosa*, *K. pneumoniae*, or *Acinetobacter* spp. [64]. With the knowledge about aminoglycoside resistance molecular mechanisms comparing to the rational prescription cited in Korea, for example, we hypothesize that low methylation rate in the nucleotide substrate of RsmH or RsmI is close to the anchor point of gentamicin in 16S RNA, indicating a

possible association with gentamicin or aminoglycosides resistance [5]*.*

RsmG, RsmH, and RsmI methyltransferases belong to the core genome (constitutive genome), while ArmA is part of the accessory genome with identical protein sequences among close species in *Proteobacteria*. Nowadays, the enzymatic activity has been well described; however the antibiotic resistance remains unsolved, perhaps as a consequence of broad usage of aminoglycoside in hospital environment, allowing the development of resistant bacteria. In the future, probably the treatment of *P. aeruginosa* will take into account the genetic trait of each isolate, strain, or species with the set of resistance genes, and surely methyltransferases will be included routinely in clinical care and high throughput or genomic medicine therapies.

We thank the University of Antioquia for their financial support to PhD student

**60**

Pablo Valderrama-Carmona, Jaison H. Cuartas, Diana Carolina Castaño and Mauricio Corredor\* Gebiomic group, Natural and Exact Sciences Faculty, University of Antioquia, Medellín, Colombia

\*Address all correspondence to: mauricio.corredor@udea.edu.co

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
