Participating date: April 6, 2022
Schedule: 11:00 AM – 11:20 AM
General Description: Pseudomonas aeruginosa and Staphylococcus aureus are multidrug resistant pathogenic bacterium considered by the CDC as a serious threat with urgent treatment needs. Carbapenems are last resort broad-spectrum antibiotics used to treat resistant bacteria. However, resistant strains produce carbapenemases to evade antibiotics making them difficult to treat. An alternative treatment that has been revisited experimentally involve the use of phage therapy (PD), which employs the specificity and bactericidal properties of bacteriophages to target specific strains. This research seeks to isolate P. aeruginosa and S. aureus bacteriophages. Given these bacteria are found in wastewaters and bacteriophages can survive with their host, samples from a wastewater treatment plant in Mayagüez, Puerto Rico were collected and used as sampling sites. To increases the bacteriophages concentration, an enrichment was performed by inoculating wastewaters filtrate with their respective hosts (P. aeruginosa (ATCC 19660) and S. aureus (ATCC 25923)), after amplification, the presence of the phages was confirmed using bacterial lawn-spotted test and plaque assays. Bacteriophages were successfully isolated, being necessary to dilute the sample to 10-6-10-12 to avoid concurrent lysis in the plaque assay. The estimated bacteriophages in the lysate of P. aeruginosa was 2.5 x 1012 pfu/mL, and the average diameter of the plaques ranged from 0.8 to 1.0 mm. However, the estimated bacteriophages in the lysate of S. aureus was .35x1011pfu/mL, and the diameter of the plaques was 0.4mm. The specificity test of the isolated bacteriophages of P. aeruginosa and S. aureus was tested with a bacterial group that included certifies strains of P. aeruginosa, S. aureus, Escherichia coli, Klebsiella pneumoniae, Klebsiella aerogenes, Bacillus subtilis, and Salmonella diarizonae. The presence of plaques was only found in their respective host. The phages obtained were amplified according to the Large- and Small-Scale Preparation of Bacteriophage Lysate protocol, in order to develop the morphological characterization by Transmission Electron Microscope (TEM) and molecular characterization. The morphological analysis of the isolated bacteriophages will be determined using TEM. At the molecular level, the genetic material of the bacteriophages of S. aureus and P. aeruginosa has been successfully extracted, this being DNA and not RNA. The molecular weight of both bacteriophages is approximately 23kb. These findings confirm the presence of bacteriophages in the environment tested, allowing to test its potential used as bioprospect in phage therapy to antibiotic resistance strains of P. aeruginosa and S. aureus.
Interested Majors
Microbiology (BIOL)
Level of Education
Graduate
Professor/Advisor
Prof. Carlos Rios Velazquez
Schedule
April 6, 2022
11:00 AM – 11:20 AM
Google Meet Link
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