Welcome to another lecture
on this series on the human microbiome.
I'm Pat Cleary.
I'm a Professor of Microbiology
at the University of Minnesota.
I've spent many years
working on the pathogenesis
of group A Streptococcus.
You'll notice in my title
that I have a subtitle "Yin & Yang
of Infectious Disease".
This is a special interest of mine
because there are many bacteria
which are members of the microflora,
cause no problems at the time,
but have the potential
to also cause very serious infections
and are considered primary pathogens.
Those same pathogens can also
revert back to being normal flora.
As I'm sure you've learned already
from some of the other lectures,
our bodies are gardens
Some see the sun,
they're on our skin.
Some line the dark passages,
such as our intestines.
While others are just
During this presentation,
I'll touch on several different genera
that can be either normal flora
or primary pathogens.
I'll spend a considerable time
agalactiae, and pneumoniae.
I'll touch on Staph aureus, and
I'll talk some about bifidobacterium,
as a helpful member of the normal flora.
And I'll mention Enterococcus
as a source of antibiotic resistance.
The next three slides will give you
a taste of what the microflora
is on different parts of the body.
Again though, I will tend to focus
on Gram positive bacteria.
And we'll start with the outer surface,
which in fact is primarily Gram positive
and can contain anywhere from 1,000
to 10,000 bacteria per centimeter.
Staph aureus is common
and Staphylococcus epidermidis.
Corynebacteria are there,
they're not pathogenic.
The hair follicles
are quite interesting actually,
because they have their own microflora.
The Gram positive bacterium,
Propionibacterium acnes is one example.
And as some of you know,
when you reach puberty,
the number of these bacteria increase
because of the chemical changes
in the sebaceous secretions,
and pimples result,
the bane of being a teenager.
Blood, spinal fluid,
and tissue spaces are sterile.