Difference between revisions of "Team:elan vital korea/Project Overview"

PROJECT OVERVIEW

Bacteria acquiring resistance to antibiotics pose serious health problem globally. Following last year’s example,
the project of Elan Vital Korea for this year also is related to MRSA. This year, however, we have focused
on early detection of MRSA infection using quorum sensing. Below, we have briefly described the health threats
caused by MRSA, and have explained the quorum sensing method. Then, we have proceeded to the description
of how we designed and implemented our experiments, and what results we have obtained. Finally, we have briefly
outlined the implication of our results and future plans.

Threats of Antibiotics-Resistant Bacteria

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What makes the problem more pressing is that the data isbased on the reports of clinical samples from
laboratories, “predominantly in hospital settings” (Antimicrobial Resistance: Global Report on
Surveillance 2014, WHO, 2014, p. 70), which means community-acquired (compared to health-care associated)
infections and uncomplicated infections are underrepresented.

Existing Methods Used for Detection

CDC’s efforts at outsmarting the antibiotic resistance focuses on 4 core actions: detect, respond, prevent
and discover. The project is called AR Initiative (Detect and Protect Against Antibiotic
Resistance Initiative), which is an integral part of the CDC strategy to target investment aimed at AR.
Among the AR initiative, detection is the first step that impacts the whole controlling process.
Detecting antibiotic resistance quickly and effectively is crucial for determination of the treatment methods
for different patients as well as for quarantines to prevent it from becoming epidemic.
Currently, several methods are used for the detection of the antibiotic resistance. Most common and traditional
method is using growth inhibition assays performed in broth or by agar disc diffusion.
For clinically critical bacteria, diagnostic laboratories perform phenotypic-based analyses using standardized
susceptibility testing methods, usually in accordance with the guidelines published by the Clinical
and Laboratory Standards Institute.

Using the culture-based approach, it can take 1—2 days to produce results for fast-growing bacteria such as
Escherichia coli orSalmonella, but several weeks for slow-growing bacteria such as Mycobacterium tuberculosis.
Moreover, culturing only works for a small fraction of microbes; although most pathogens can be cultured
relatively easily thanks to years of accumulated experimental experiences, the vast majority of microbes cannot
grow outside their host environment, including pathogens such as Chlamydia orTrypanosomes.

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Using newer molecular detection techniques for antibiotic resistance such as quantitative PCR (qPCR) or microarrays, we can determine
the presence of specific resistance genes within hours, and we obtain improved diagnosis results. However,
these culture-independent approaches target well-known and well-studied pathogens or resistance-causing genes only,
and cannot be easily used for broader spectrum screening.

Using the culture-based approach, it can take 1—2 days to produce results for fast-growing bacteria such as Escherichia coli
orSalmonella, but several weeks for slow-growing bacteria such as Mycobacterium tuberculosis. Moreover, culturing
only works for a small fraction of microbes; although most pathogens can be cultured relatively easily thanks
to years of accumulated experimental experiences, the vast majority of microbes cannot grow outside their host environment,
including pathogens such as Chlamydia or Trypanosomes.

Using newer molecular detection techniques for antibiotic resistance such as quantitative PCR (qPCR) or microarrays, we can determine the
presence of specific resistance genes within hours, and we obtain improved diagnosis results. However, these
culture-independent approaches target well-known and well-studied pathogens or resistance-causing genes only,
and cannot be easily used for broader spectrum screening.

CDC dramatically innovated the detection process by adopting the Advanced Molecular Detection (AMD), which combines the latest
pathogen identification technologies with bioinformatics and advanced epidemiology to more effectively understand, prevent and
control infectious diseases. Using those technologies, it is possible to rapidly look for a microbe's match among
thousands of reference samples in the microbe library. If no match is found, the whole genomic sequence
of the microbe's DNA code can be taken, then quickly analyzed using disease detective works and bioinformatics
to answer critical disease-response questions. However, this new method, while it sounds
very interesting, is not to be completed until 2020, and still requires incubation, as well as being expensive.

Our Hypothesis: Possibility of Using Quorum
Sensing for Early Detection

Our team, Elan Vital Korea, addressed the problem of rapidly detecting antibiotic-resistant bacteria. We were interested in
a rapid and efficient method of antibiotic resistance detection, and we believed that such a method could be engineered
using quorum sensing. Our hypothesis was that we would be able to use quorum sensing – a method bacteria
use to communicate with each other – to make the cells quickly report the existence of antibiotic-resistant bacteria

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Using the culture-based approach, it can take 1—2 days to produce results for fast-growing bacteria such as Escherichia coli orSalmonella,
but several weeks for slow-growing bacteria such as Mycobacterium tuberculosis. Moreover, culturing only works
for a small fraction of microbes; although most pathogens can be cultured relatively easily thanks to
years of accumulated experimental experiences, the vast majority of microbes cannot grow outside their host
environment, including pathogens such as Chlamydia orTrypanosomes.

LUsing newer molecular detection techniques for antibiotic resistance such as quantitative PCR (qPCR) or microarrays, we can
determine the presence of specific resistance genes within hours, and we obtain improved diagnosis results. However, these
culture-independent approaches target well-known and well-studied pathogens or resistance-causing genes only,
and cannot be easily used for broader spectrum screening.

CDC dramatically innovated the detection process by adopting the Advanced Molecular Detection (AMD), which combines the latest
pathogen identification technologies with bioinformatics and advanced epidemiology to more effectively
understand, prevent and control infectious diseases. Using those technologies, it is possible to rapidly look for a microbe's match
among thousands of reference samples in the microbe library. If no match is found, the whole genomic sequence of the microbe's
DNA code can be taken, then quickly analyzed using disease detective works and bioinformatics to answer
critical disease-response questions. However, this new method, while it sounds very interesting,
is not to be completed until 2020, and still requires incubation, as well as being expensive.

For the project, we have developed a reporter cell that expresses GFP in the presence of the QS signaling molecule acyl homoserine lactone (AHL).
Our test cells (which act as a simulation of antibiotic-resistant bacteria) express lactonase, which breaks down AHL.
In our experimental system, test cells should signify their presence by breaking down AHL and
preventing GFP expression in reporter cells.

Experiment: Process and Results

There are many ways of utilizing quorum sensing for medicinal use, and one of the most intuitive and
most well-known methods is quorum quenching. Quorum quenching takes advantage of the fact that quorum sensing
also plays a role in expressing virulence, and interferes with the quorum sensing that produces virulence.

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