Date of Completion

2023

Document Type

Thesis

Degree Name

Bachelor of Science in Medical Laboratory Science

Keywords

Psidium guajava, Enterobacter cloacae, Bacteriophage, Synergistic effect

Abstract

The development of multi-drug resistance has been a great concern in recent years, specifically the resistance of organisms to carbapenems, a class of antibiotics that is often used as a last option to treat bacterial infections (Annavajhala et al., 2019). One of the bacteria that is considered carbapenem-resistant is Enterobacter cloacae, a gram-negative bacillus under the family of Enterobacteriaceae. It is classified as priority one for Research and Development of new antibiotics according to the World Health Organization (WHO, 2017). Plant extracts, such as Psidium guajava (Guava), was found to have antimicrobial properties that can inhibit gram-positive bacteria and some gram-negative bacteria. Another alternative treatment for bacterial infections is bacteriophage therapy which utilizes bacteriophage, a virus that poses no harm to humans but can destroy bacteria. To maximize its inhibitory effect, synergizing isolated bacteriophage and crude ethanolic extract of guava was done instead of using bacteriophage alone or guava alone. To test its synergistic effect, crude ethanolic extract of Psidium guajava was combined with the isolated bacteriophage lysate with a titer of 10^7 through Broth Microdilution Assay to determine its Minimum Inhibitory Concentration (MIC). Results showed that the MIC of Psidium guajava (Guava) leaf is 6.25 mg/mL, the PFU/mL of the isolated bacteriophage is 1.31 % 10!", the MIC of isolated bacteriophage is 3.98 % 10#, and the FIC index to determine the synergism of Psidium guajava (Guava) and isolated bacteriophage is 35,345. Based on the computed FIC, the Psidium guajava (Guava) leaf extract and bacteriophage has antagonistic effect; the guava leaf extract, when combined with bacteriophage, lessen the antimicrobial activity as compared to bacteriophage alone. This may be caused by the other active components of guava leaf which added to its antagonistic result. However, purifying and selecting specific active components may lessen the antagonistic effect.

First Advisor

Jennilyn Nicole G. Mendoza

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