Evaluación de la actividad antibacteriana de bacteriófagos sobre Pseudomonas aeruginosa, Staphylococcus aureus y Escherichia coli”

Abstract

Pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli are responsible for various human infections, diseases and deaths, which represent a challenge for global health since to combat them, indiscriminate and irresponsible use of antibiotics has been made. From here arises the central problem of this research: antimicrobial resistance, which has driven the search for effective alternatives to combat these infections. Bacteriophages, which are viruses that infect bacteria, injecting their genetic material inside them and then multiplying inside the bacterial cell and killing it after causing its lysis by releasing the new phage particles, have been positioned as therapeutic tools to eliminate specific bacteria. Thus, in this work, specific bacteriophages for Escherichia coli ATCC 27853 were isolated from wastewater samples of the Machangara River in the city of Quito. Furthermore, the antibacterial activity of the isolated phage was evaluated quantitatively, obtaining the phage titer of 1.2x105 PFU/mL corresponding to the 10-4 dilution as the best concentration of the bacteriophage that inhibits the growth of the bacteria in question. On the other hand, it was possible to purify the bacteriophage to characterize it phenotypically through variations in pH and temperature and thus know what the optimal conditions are in which the bacteriophage manages to infect the bacterial cell. The pH 7 being ideal for Escherichia coli lysis to occur. Likewise, at temperatures between 37 °C and 50 °C, the bacteriophage shows thermal stability and thus manages to form lysis plaques.