Background: The occurrence of multidrug-resistant bacteria has led to one of the greatest
challenges in public health care. Bacteria are continuously evolving resistance mechanisms,
such as extended spectrum β-lactamases, which alters the effect of antibiotics and thereby limits
treatment options. It is therefore crucial to find possible solutions in order to prevent further
escalation. Factors such as antibiotic stewardship programs, new antibacterial agents, and
faster antibiotic susceptibility testing are keynotes in the combat against these microorganisms.
Methodology: In this project, we evaluated the antibacterial capabilities of phytochemicals
extracted from Salicornia Ramosissima obtained by aqueous or organic solvent based extraction.
Bactericidal and bacteriostatic tests were performed using the agar well diffusion method
and an optical density test. In addition, the potential of determining bacterial resistance proteins
to identify resistance mechanisms using fast LC-MS/MS for novel antibiotic susceptibility
testing by advanced biotyping was also assessed. This involved extraction of bacterial proteins
with S-trap based in-situ proteolysis and fast analysis through the Fast LC-MS/MS analysis
coupled to ion-mobility tandem mass spectrometry.
Results: We did not observe any bactericidal or bacteriostatic effect from the phytochemicals
extracted from Salicornia Ramosissima at the available concentrations of bioactive compounds.
For the advanced biotyping, we were, however, able to identify 30 resistance proteins using
LC-MS/MS, three of which (TEM-55, SHV-65, and CTX-M-82) are related to ESBL.
Conclusion: In this study, we can conclude that the concentration of phytochemicals needs
to be higher before an antibacterial effect is possible. However, LC-MS/MS demonstrated
promising results in determining resistance proteins and the potential of incorporating this
system in AST should further analysed.