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Printable Handouts
Navigable Slide Index
- Introduction
- Definition of drug resistance
- Two types of evolutionary biologists
- Two reasons to study the evolution of drug resistance
- The pathogens I will talk about today
- Discovery of HIV
- Antivirals for HIV stopped working
- Mutations in HIV genome lead to resistance
- RT gene, amino acid position 67
- Asp 67 to Asn in patient 102 of Bacheler dataset
- The resistant strain is taking over the virus population in the body
- Selective sweep – diversity lost
- Transmitted drug resistance
- Cheat sheet for resistance mutations in HIV
- Combination therapy for HIV prevents evolution
- In the mid-'90s triple-drug therapy became available
- HIV drug resistance evolution main takeaways
- The pathogens I will talk about today: Mycobacterium tuberculosis
- Mycobacterium tuberculosis – a bacterium
- Reminder of drug resistance (here antibiotic resistance)
- Mycobacterium tuberculosis is very common
- Treatment
- Drug resistance
- One unlucky TB patient
- Resistant strains of Mycobacterium can evolve
- Resistance evolution within patient and clonal interference
- Clonal interference also happens in HIV
- Resistant strains of Mycobacterium can be transmitted to others
- Resistant strains of Mycobacterium can be transmitted
- TB main takeaways
- The pathogens I will talk about today: MRSA
- The number of deaths due to MRSA increased and then decreased in the 2000s
- What makes MRSA methicillin resistant?
- mecA is part of the SCCmec element
- SCCmec is 52,000 base pairs long
- How does mecA make S. aureus resistant?
- Horizontal gene transfer (HGT)
- We know that HGT happens, but observations are rare
- How often does drug resistance evolve?
- MRSA main takeaways
- Conclusion
Topics Covered
- Drug resistance
- Transmission vs. evolution of drug resistance
- Mycobacterium tuberculosis
- MRSA (Methicillin-resistant Staphylococcus aureus)
- HIV (human immunodeficiency virus)
Links
Series:
Categories:
Talk Citation
Pennings, P. (2023, November 30). Evolution of drug resistance [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved October 13, 2024, from https://doi.org/10.69645/QDHX8391.Export Citation (RIS)
Publication History
Financial Disclosures
- There are no financial matters to disclose.
Other Talks in the Series: Introduction to Evolutionary Biology
Transcript
Please wait while the transcript is being prepared...
0:00
Hi everyone.
My name is Pleuni Pennings,
and I'm an Associate Professor
at San Francisco
State University.
I use population genetic theory
and analysis of patient data
to study the
evolution and spread
of drug resistance in
human pathogens to find
better ways to prevent
drug resistant infections.
Today,
I will talk about the evolution
of drug resistance in HIV,
Mycobacterium tuberculosis,
and Staphylococcus aureus.
The lecture will include
information also
on selective sweeps and
clonal interference.
0:39
According to Wikipedia
drug resistance is the reduction
in effectiveness
of a medication,
such as an antimicrobial,
in treating a disease
or condition.
In other words, we speak
of resistance when
a medication such
as an antibiotic
which normally works on
a pathogen like bacteria
in the sense that it kills it
or it makes that it
cannot replicate,
doesn't work anymore.
The pathogen, bacteria,
viruses or other pathogens
are now resistant
to the medication.
This picture illustrates
drug resistance.
In the upper panel,
we first see how
bacteria multiply,
but then when the patient
takes antibiotics,
the bacteria die.
In the lower panel however,
the bacteria are resistant.
They don't die when the
antibiotics are used.
That means that the antibiotics
cannot cure the patient.
What you see in this
picture as well is
that the genetic material
of the bacterium,
a circular genome,
now has an added red piece
in the lower panels.
This additional piece of
the genome can be a gene
or a set of genes that
cause drug resistance.
Drug resistance
can also be caused
by smaller changes
to the genome.
Sometimes a simple mutation that
leads to a single
letter change is enough
to make a pathogen
resistant to a drug.
We'll see that in HIV and
Mycobacterium tuberculosis.