5. INTRODUCTION
Bacteria
Antoni van Leeuwenhoek discovered bacteria.
Single celled microorganisms,invisible to naked eye.
Disease development:
Bacterial pathogen enters host .
Growth of bacteria.
Production of toxic substances occurs.
They can be treated by antibiotics. 5
6. Antibiotics
An antibiotic is a type of antimicrobial substance
active against bacteria.
They work by killing the bacteria by making it
hard for the bacteria to grow and multiply.
The classic treatment of bacteria induced
infectious diseases is antibiotic applications such
as Penicillin , ciprofloxacin , ampicillin ,
methicillin etc
6
ANTIBIOTICS & ESSENTIAL OILS
7. ESSENTIAL OILS
7
Essential oils
Plant derived compounds
Plant extracts , made by steaming or pressing various
parts of plants to capture the compounds that we
need.
Many essential oils help protect against bacterial
Infection such as
Peppermint oil , cinnamon oil , clove oil etc.
Metabolites, have the ability to penetrate the cell
membranes of the bacteria and interact with the
protein targets.
8. WORKING
Six commercial antibiotic compounds
ciprofloxacin, gentamicin, sulfamethoxazoletrimethoprim, nitrofurantoin,
ampicillin, and colistin sulfate
Four simple essential oils
peppermint (Mentha piperita), clove (Syzygium aromaticum), elemi
(Canarium luzonicum), bergamot (Citrus bergamia)
Three mixtures of essential oils
M1 > combine 5 essential oils
M2 > combine 6 essential oils
M3 > combine 10 volatile oils 8
9. WORKING
Antimicrobial activity
We selected one Gram-positive bacterial strain,(Enterococcus durans)
and two Gram-negative strains,(Aeromonas species)
The mechanism of action of the antibiotic agents used against the three
investigated bacterial strains was investigated using single-bacteria
surface-enhanced Raman spectroscopy (SERS)
9
10. BACTERIAL STRAINS
The bacterial strains were grown in Luria Broth media and incubated at
37°C for 24 h .
The antibacterial activity were determined using the
Paper disk diffusion method
Six standard antibiotics
3-bacterial Strains
10
13. SURFACE-ENHANCED RAMAN SPECTROSCOPY
Surface-enhanced Raman spectroscopy or surface-enhanced Raman
scattering (SERS) is a surface-sensitive technique that enhances
Raman scattering by molecules adsorbed on metal surfaces.
What can SERS be used for?
The power of SERS lies in its ability to identify chemical species and
obtain structural information in a wide variety of fields including polymer
and materials science, biochemistry and biosensing, catalysis, and
electrochemistry.
13
14. SURFACE-ENHANCED RAMAN SPECTROSCOPY
SERS has the ability to analyze the composition of a mixture at a
nanoscale makes the use of SERS substrates that are beneficial for
pharmaceuticals, material sciences, drug detection, food quality analysis
etc.
Why do we use nanoparticles in SERS?
Surface enhanced Raman scattering (SERS) nanoparticles are an
attractive alternative to fluorescent because of their photostability and
multiplexing capabilities. 14
15. 15
As this band intensity decreases with antibiotic
treatment, we can conclude that the cell wall
structure is altered and the ability of the cells to
duplicate or survive is highly endangered.
the cell wall structure is the target of these
antibiotics and we also collected the SERS signature
of the bacterial cell wall
Figure1:Raw single cell SERS spectra
enterococcus durans showing the spectral profile
in three situations: resistance, control, and
sensitivity to antibiotics control
16. The effect of the drugs is reflected by the
spectral data shown in Figures 1 and 2 as
affecting the 653 -732 and 1282–1337 cm-
1 band intensities
The cell wall structure is the target of
these antibiotics.
we also collected the SERS signature of
the bacterial cell wall
16
Figure 2: single cell SERS raw spectra of
Aeromonas media showing the spectral profile in
three situations: resistance, control, and sensitivity
to antibiotics
17. REFERENCES
Dina, N. E., H. Zhou, A. Colniță, N. Leopold, T. Szoke-Nagy, C. Coman, and C.
Haisch. 2017.Rapid single-cell detection and identification of pathogens by using
surface-enhanced Raman spectroscopy. Analyst142:178289.doi:10.1039/c7an00106a.
Ghabraie, M., K. Dang Vu, L. Tata, S. Salmieri, and M. Lacroix. 2016. Antimicrobial
effect of essential oils in combinations against five bacteria and their effect on
sensorial quality of ground meat. LWT-Food Science and Technology 66:332–39.
doi:10.1016/j.lwt.2015.10.055.
Kahraman, M., M. Müge Yazici, F. Şahİn, Ö. F. Bayrak, E. TopÇu, and M. Çulha.
2007.Towards single-microorganism detection using surface-enhanced Raman
spectroscopy. International Journal of Environmental Analytical Chemistry 87:763–
70.doi:10.1080/03067310701336379. 17
