Why do some cleaners only kill 99.9% of bacteria?
What happened to the 0.01%?
the same principle of imperfection can be applied to what
we are going to talk about today.
Bacterial fighting drugs known as antibiotics help to kill the
bacteria that make us feel sick.
Unfortunately,
today we are finding that the way we use antibiotics
is creating a bigger problem,
superbugs are bacteria that have gained a resistance several antibiotics.
When using an antibiotic a large portion of the susceptible
bacteria gets killed to put a small number don't.
a.k.a. the 0.01%
over time.
These bacteria divide and carry on their antibiotic resistance genes.
This result in an antibiotic not being effective over time.
One common superbugs seen both inside and outside,
the hospital is a methicillin-resistant.
Staphylococcus aureus MRSA.
The bacteria is a leading cause of skin and soft
tissue infection such as abscess and cellulitis.
Talking to us today is a physician from the Hamilton
General Hospital and Associate chair of Education in,
pathology and molecular medicine at McMaster University in Hamilton Ontario.
My name is Cheryl Main,
I'm a medical microbiologist and infectious disease doctor and I work
at the Hamilton
General Hospital,
I'm also an educator.
So I'm the associate chair of education for the Department
of pathology and molecular medicine,
at McMaster has been part of my time doing research
and part of my time doing education.
The rest of my time doing lab work in patient
Methicillin-resistant staphylococcus aureus or MRSA is a
form of staphylococcus aureus that has become resistant to methicillin,
actually,
not a drug leaves and people it's one that we
use traditionally in the lab.
So,
staphylococcus aureus is a really common bacteria,
a good percentage of the population carry it on their
skin and in their nose.
It likes areas like your armpits in your groin.
And it is a really common cause of skin and
soft-tissue infection like cellulitis.
It can also cause more.
Aggressive infections,
bloodstream infections,
heart infections endocarditis,
basically,
anybody system can get infected with the bug.
So,
the garden-variety staphylococcus aureus causes big problems on its own,
but it has a number of drugs,
which will treated when it develops resistance.
Then the number of drugs we can use to treat.
It goes down significantly and so we have very limited
treatment options so we ended up having to use drugs
like Vancomycin which are toxic to kidneys or new
drugs,
which are very expensive,
like linezolid or daptomycin,
and so these
patients end up having to be on expensive drugs that
you're hard to get with lots on monitoring and if
we underdose those drugs or we don't treat them appropriately,
if you don't get rid of the source of the
infection that a bug can become even more resistant.
And we all live in fear of a bug called
vancomycin-resistant staphylococcus aureus,
which has developed resistance to our first-line drug,
which is Vancomycin
Bacteria become superbugs in a number of ways to defend
them the drugs that you become resistant to.
So most of the super bugs have acquired resistance genes
from other bugs and so are those neon a plasmid
or exchanged sexually with other bacteria,
exchange genetic information some bugs,
develop enzymes to break down the antibiotic.
So,
the beta-lactamases are a good example of that.
Some bugs will prevent the anaesthetist from getting into them,
so they changed the lock the door that the antibiotic
normally gets in.
it's not effective anymore.
And some just,
for example,
Vancomycin intermediate staphylococcus aureus it just the bank of my
snacks on the cell wall.
So the bug creates a thicker cell wall.
So there's more targets of the drug is less effective.
So I always describe bacteria thing intelligent,
they're not,
they don't really have brains but they figure a way around
whatever.
Antibiotic we put to them,
they will adapt to try to survive.
And often they'll give up their own genetic fitness to
gain more resistance and to avoid being killed by the
antibiotics in the environment of the ways,
to prevent resistance are to avoid using antibiotics and necessarily
and be very judicious with how how we use them
when we use them,
it's by Far and Away the best way.
Emarsys important in the hospital because it is pretty
common and easily transmitted on hands of healthcare providers.
So the nurse who takes care of the patient,
may lose them in their bad.
Can get MRSA on their hands and then spread
it to the next patient in once you get colonized
with it once,
it's hanging out on your skin to leave her to
get rid of it.
some of the research I've done,
it looked at ways to get rid of that bug.
So patients,
who are free sample going to long-term care facilities?
It is better for them.
If they don't have MRSA,
that goes with them.
The problem is,
it's very hard to get rid of it in those
patients who are generally unwell.
And what we have found is it sometimes the plants
to get rid of the bug.
Actually just make it more resistant.
So we have to be very careful.
There are a few old drugs that work for MRSA.
So some of the strains are sensitive to any antibiotic
called clindamycin which is an oral antibiotics been around a long time,
more and more we see resistance to that one.
Then other oral agents would be something called Septra or
trimethoprim-sulfamethoxazole or doxycycline.
So we use those oral agents in those patients,
with life-threatening infection.
Vancomycin becomes our first-line drug and Vancomycin if the dosing
is too low,
the bug becomes resistant.
So we see Vancomycin intermediate,
staphylococcus,
aureus or vancomycin-resistant staphylococcus aureus,
which we have not seen Canada,
so Vancomycin tricky.
You want to give them enough drugs to kill the
bug but not so much that you damage your kidneys,
the drug that has really replaced vancomycin
for lot of stuff for his Factory in yet or
MRSA is daptomycin and again that drug requires some monitoring
but it's less toxic
and there are new drugs coming along
like septobrypol
which we don't have easy access to
Yeah.
So I did a meta-analysis looking at the decolonization framers
day and the interesting thing was that the decolonization
appears to be the least effective in the patients.
We need it most in.
So those patients that are clinically unwell elderly.
Lots of comorbidities are more likely to develop resistance organism
and less likely to get colonized swear as patients were
young and healthy and can get at a hospital and
stay at the hospital are more likely to be effectively
decolonized since I did that.
You there have been a number of studies looking at
effective decolonization strategies and there are some strategies that appear
to be effective using a systemic antibiotic combined with chlorhexidine,
body,
wash and topical antibacterial in the nose to get rid
of the stuff for us and we are using those
under just specific clinical indications of space.
Recurrent infections.
We may try to connotation but we're more likely to
do that in those patients there otherwise healthy because of
this the day that we got from my previous study
would show that you're more likely to generate resistance if
they're not otherwise healthy.
Well,
I think everybody has a an opportunity to help fight
resistance and the the way you do that is to
not ask for antibiotics when you don't need them.
So it's very hard as a position to not give
a patient antibiotics when they really are demanding it.
And I know a lot of my colleagues and myself
at times we just,
we give in to the pressure and so patients can
help by not putting that applying that pressure viral diseases,
don't get better with antibiotics and we need to stop
treating them.