Please enable JavaScript.
Coggle requires JavaScript to display documents.
Antibiotic Resistance in Bacteria - Coggle Diagram
Antibiotic Resistance in Bacteria
Antibiotics
D: drugs developed
to kill bacteria
Disrupt Cell Wall
Formation
inhibit enzyme involved cell wall formation
bacterial cell bursts = killed
why?
cell cannot resist osmotic pressure
due to weakened cell wall
eg. Penicillin
Inhibit Metabolic Processes
including Protein Synthesis
why useful?
erythromycin not affect larger ribosomes in eukaryotic cells
can disrupt protein synthesis in prokaryotic/bacteria cells
without damaging ribosomes of patients taking antibiotic
eg. antibiotic erythromycin destroys
ribosomes in prokaryotic cells
some antibiotic resistant bacteria are resistant
to a number of types of antibiotics
risk that some bacteria could become
resistant to ALL ANTIBIOTICS
why full course of prescribed antibiotic
should be completed?
ensure ALL bacteria is killed
as if not - ones still alive be the more resistant ones (mutated)
and continue to reproduce quickly
Why Does Resistance
Arise?
Mutations in bacterial genome
lead to metabolic changes
result in antibiotic no longer being effective
as bacteria can survive antibiotic
different mutations yield different resistances
mutations
random, rare, spontaneous changes of
bacteria's genetic material
no purpose, simply arise by chance
produce enzymes that
inactivate antibiotics
pumping mechanisms that pump
antibiotic back outside
(never reaches target)
activate different ways for bacterium
to multiply, feed or maintain structure
can function despite effect of antibiotic
close up entry ports so
antibiotics unable to get
into cell
Resistant bacteria reproduce
bacteria reproduce rapidly
by
BINARY FISSION
(asexually)
resistant bacteria pass on 'resistance gene' to their offspring
1 resistant bacterium can rapidly reproduce large pop of antibiotic resistant bacteria
Normal bacteria (not antibiotic resistant) killed by antibiotic
differential survival
proportion of resistant bacteria increases quickly
Discovery of New
Sources of Antibiotics
important to SOCIETY + the ECONOMY
for new sources of antibiotics to be found
within natural environment
new antibiotics needed to be effective
against strains of bacteria
(already resistant to current antibiotics)
benefits
more effective treatments
lower treatment costs
less time off work
(higher productivity)
Natural Environments = SOIL
some types of microbe naturally produce antimicrobial substances
as defence against competing microbes
Human Body = NASAL CAVITY
antibiotic properties of some bacteria here
Factors Affecting
Disease Spread
how easily spread from
person to person
how likely someone falls ill to
disease once infected
whether there is vaccination
for disease & % uptake of it
bacterial resistance to antibiotics
(important if bacteria cause disease)
Viruses
epidemics
diseases that spread rapidly through small region (usually within one country)
affect higher proportion of population
pandemics
affecting many thousands of people (several countries)
at the same time
cause most major
epidemics + pandemics
viruses w/ RNA as genetic material
influenza
SARS
rabies
Hendra
Ebola
Covid
why more likely cause widespread infections?
retroviruses with RNA in genome
much less stable than those w DNA
antibiotics not effective against
viruses
small genomes prone
to mutation
Antimicrobial Drugs
drugs
effective against a broader range of microbes
than antibiotics
effective against pathogens
antibiotics cannot combat (viruses)
Decrease in Infectious Rates +
Deaths from Antibiotic
Resistant Bacteria
more rigorous hygiene
in hospitals
Isolation of infected patients
more judicious approach to
the use of antibiotics
new targeted
drug treatments
Human Immunodeficiency Disease
HIV
(case study)
leads to the development of AIDS
(Acquired Immune Deficiency Syndrome)
how work?
RNA within virus
codes for production of enzyme - reverse transcriptase
reverses usual transcription process so RNA to DNA
DNA spliced into gene of infected host cell
now ‘factory’ for HIV replication
attaches to helper T-cells
reduction helper T-cells = immune response compromised
more susceptible to infection
where did it come from?
mutated from similar virus (SIV)
causes same immunodeficiency disease in chimpanzees
transferred to humans in the early 1900s
in central Africa
possibly via human being bitten by a chimp
why became
widespread?
increased air travel
more casual
approach to sex
beginning of
globalisation
treatment
ANTIRETROVIRAL
drug treatments
slow down the replication rate
extend life expectancy
of patients
genetic material within HIV virus MUTATES frequently
extremely difficult to develop vaccine against HIV
or for body to develop immune response
how does it pass?
blood
semen
vaginal fluids
breast milk
cannot pass through intact
skin or air (like a cold or flu virus)
Animals as Reservoirs
of Disease-causing Viruses
Reservoirs
animals that harbour viruses that
subsequently cause disease in human
often
suffer little harm
from
virus themselves
not vectors
- why?
not adapted to transfer pathogen
transfer usually chance event
examples -
bird flu
swine flu
BATS
significant role in
inter-species spread
examples -
Marburg
SARS
Nipah
why bats suitable?
mammals
similar physiology to humans
social animals
in close contact with large no bats
high proportion of bats carriers
increase possibility cross-infection
fly large ranges
in contact w other organisms
encroachment of humans into their habitats
due to increasing urbanisation
clearing of woodland for housing/agriculture
Detecting + Diagnosing
Infection
diagnosis of infection
improved in recent years
earlier + more
accurate
diagnosis
more effective + successful
treatments
@ earlier stage
ELISA
Enzyme-linked Immunosorbent Assay
D: technique that:
uses antibodies, enzymes + other molecules
as biomarkers
to detect presence of particular molecules
advantage
test for small/large number of potential antigens or biomarkers @ SAME TIME
STEPS
bodily fluids taken from patient + added to number of wells on a plate
range of antibodies
are added to wells
reaction between antibody + antigen triggers enzyme linked to antibody = COLOUR CHANGE
colour changes
identify antigens
used to detect:
pathogens in body
cancer cell markers
cardiac disease markers
pregnancy
enable:
early
rapid screening
provide:
wide range of diagnostic feedback
Pregnancy
implantation occurs
increased levels of hormone -
hCG
detected in blood/urine
In a pregnancy test kit - hCG antigens
detected by complementary hCG antibodies (immobilised on the ELISA plate)
formation of antigen-antibody complex
linked enzyme reacting
produces colour change
Testing for
Viral Pathogens
Viral antigens
coated with blood serum from the patient
added to ELISA plate
if patient’s blood contains corresponding antibodies for virus
antigen-antibody complex forms
triggers enzyme reaction that
produces colour change
detecting cytokines as biomarkers
of inflammation
cytokines
chemicals released by T-helper cells
as part of simmune response
during infection
small proteins help
coordinate immune response
found in blood
used as biomarkers to identify
number of conditions
TB
rheumatoid arthritis