Guava Leaf Extract Exhibits Antimicrobial Activity in Extensively Drug-Resistant (XDR) Acinetobacter baumannii

Area of Science:

• Microbiology
• Pharmacology
• Natural Products Chemistry

Background:

• Microbial resistance, particularly from Acinetobacter baumannii, is a critical global health threat.
• Phytochemicals offer a promising natural alternative to conventional antibiotics due to diverse antimicrobial mechanisms.
• Acinetobacter baumannii is identified as a highest-priority pathogen by the World Health Organization (WHO).

Purpose of the Study:

• To evaluate the antimicrobial effects of guava (Psidium guajava L.) leaf extract against extensively drug-resistant (XDR) Acinetobacter baumannii.
• To assess the impact of purifying polyphenolic compounds and combining the extract with gentamicin on antimicrobial activity.
• To investigate the cytotoxic effects of the guava leaf extract on A549 lung cell line.

Main Methods:

• Agar diffusion and microdilution methods were employed to determine antimicrobial activity and minimum inhibitory concentrations (MICs).
• Polyphenolic compounds from the extract were purified to assess their enhanced antimicrobial potential.
• Synergistic effects were evaluated by combining the extract with the antibiotic gentamicin.
• Cytotoxicity was assessed using the A549 lung cell line.

Main Results:

• Guava leaf extract demonstrated antimicrobial activity against all ten clinical isolates of XDR Acinetobacter baumannii.
• Purification of polyphenols and combination with gentamicin significantly improved the antimicrobial efficacy of the extract.
• Exposure to the plant extract induced morphological changes in A549 lung cells within 24 hours.

Conclusions:

• Psidium guajava L. leaf extract possesses significant antimicrobial properties against extensively drug-resistant Acinetobacter baumannii.
• Polyphenol purification and synergistic combination with gentamicin enhance the extract's therapeutic potential.
• The study highlights guava leaf extract as a viable natural agent for addressing antibiotic resistance challenges.