Caracterización de los fagos de Klebsiella pneumoniae con potencial biotecnológico

Torres Herrero, Beatriz
Jalasvuori, Matti (dir.) ; Penttinen, Reetta (dir.)

Gonzalo Asensio, Jesús (ponente)

Universidad de Zaragoza, CIEN, 2018
Departamento de Microbiología, Medicina Preventiva y Salud Pública, Área de Microbiología

Graduado en Biotecnología

Resumen: The extensive use and misuse of antibiotics has led to an increased emergence of multidrug-resistant Klebsiella pneumoniae strains. They are a serious concern worldwide due to their propensity to spread and the scarce effective treatments left. Consequently, phage therapy is garnering renewed interest as an alternative method to defeat antibiotic resistant bacteria. Phages – natural pathogens of bacteria – have several properties: high capacity to replicate and host specificity that turns them into a great advantage over antibiotics. Eight bacteriophages infecting Klebsiella pneumoniae were characterized according to their genetic material and morphology by performing endonuclease digestions and transmission electron microscopy imaging with 1% phosphotungstic acid or 2% uranyl acetate as staining dyes. Then, they were classified in agreement with their morphological characterization. Seven phages (EKP3P1, EKP3P2, EKP3P4, EKP3P5, EKP8P2, EKP8P3 and EKP8P4) were classified into Siphoviridae family showing hexagonal heads with long non- contractile, sometimes flexible tails and closely related restriction patterns. EKP8P1 phage was classified into Podoviridae family showing an icosahedral head with a short non-contractile tail and a different restriction pattern. They all belong to Caudovirales order. Moreover, a prophage was found in EKP8P1 sample, and classified into Siphoviridae family according to its morphology. The genome of EKP3P5 phage, a double stranded DNA of 47,622 bp long, was sequenced and annotated manually. EKP3P5 phage is a temperate phage encoding integrase, holin and endolysin proteins, among others. Therefore, EKP3P5 could not be used in phage therapy due to the risk of transferring virulence and resistance genes to the host bacteria. For all the above reasons, this thesis provides detailed knowledge of the physical structure along with genomic qualities of eight bacteriophages infecting multidrug- resistant Klebsiella pneumoniae strains. This is important for determining the potential of phages as therapeutic agents and the first step to improve phage therapy.

Tipo de Trabajo Académico: Trabajo Fin de Grado