Transcript Susceptibility of Antibacterial Chemicals on Pseudomonas

Susceptibility of Antibacterial
Chemicals on
Pseudomonas aeruginosa
Research performed by:
Clayton Brady
Health Science Biology Major
Tennessee Technological University
Introduction
•
Many diseases arise from bacteria that grow
resistant to the agents that are made to combat
them.
• Through new research, scientists can develop
new antimicrobial agents and antibiotics to
ensure the elimination of a bacterium for a
limited period of time.
• Pseudomonas aeruginosa is responsible for
16% of nosocomial pneumonia cases , 12% of
hospital-acquired urinary tract infections , 8% of
surgical wound infections , and 10% of
bloodstream infections.
Objective/Hypothesis
• The objective of my research is to determine if
chemicals commonly found in the antibacterial
sprays we use so abundantly today can in fact
render potentially hazardous bacteria, such as
Pseudomonas aeruginosa, non-viable.
• I believe that the chemicals will have no effect
on Pseudomonas aeruginosa.
Materials
• This experiment required Petri dishes, a
synthetic stock of Pseudomonas aeruginosa, an
inoculation loop, and a sterilizer (incinerator) for
streaking the plates.
• For my chemicals I used Isopropyl Alcohol, 1 M
Hydrochloric Acid, 5 % Hypochlorite Bleach, and
Vesphene.
• In order to have the bacteria to grow we needed
an incubation device.
• A ruler was needed to measure the zone of
inhibition around the discs.
• Finally an autoclave was required to sterilize the
tools after use.
Methods
• Using aseptic techniques, the experiment began
with taking an inoculating loop, sterilizing it by
way of heating it, and obtaining a sample of the
bacteria being used.
• The bacteria were then exposed to discs dipped
in each of the four chemicals. The dishes were
separated into quadrants for each of the four
chemicals tested.
• The bacteria were given a day to grow and on
the third day the zone of inhibition was observed
and measured for results.
Results
• After careful aseptic experimentation, I
was able to kill Pseudomonas aeruginosa
with the antibacterial chemicals used in
the experimental process.
• Vesphene, Isopropyl Alcohol and the 1 M
Hydrochloric Acid were unable to kill the
bacteria.
Results Cont.
Pseudomonas aeruginosa Disk Diffusion
Chart
Disc Diffusion Assays
Susceptible
Resistant
Isopropyl Alcohol
+
1 M HCl
+
5 % hypochlorite bleach
Vesphene
+
Zone of
Inhibition
21 millimeters
+
Discussion
• The other chemicals, perhaps effective on other
types of bacteria, were ineffective against
Pseudomonas aeruginosa.
• I originally wanted to test household sprays
against this bacteria, but after closer
examination I realized that the same chemicals
are in most of the sprays.
• In order to continue my research I changed the
sprays to specific chemicals commonly used to
“sterilize” equipment and tools in hospitals.
Project Summary
• Pseudomonas aeruginosa is an opportunistic
pathogen that engages in a plasmid exchange
with other bacteria making it very hard to kill
because of its ability to build resistance to many
cleaners and medicines.
• By subjecting Pseudomonas aeruginosa to
chemicals found in many hospitals and often
used to sterilize equipment, I learned that many
chemicals claiming to kill bacteria do not work on
Pseudomonas aeruginosa.
Conclusions
• Bleach (5% hypochlorite solution) was
found to be an effective antibacterial agent
proving my hypothesis wrong.
• Although Isopropyl alcohol, vesphene, and
HCL (1M) may disinfect some bacteria it is
not effective as an antibacterial agent
against Pseudomonas aeruginosa.
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