Haemophilus, a bacteria.
The Haemophilus are small, gram-negative, pleomorphic,
The Haemophilus grow aerobically or occasionally
but they also are known to be obligate parasites of mucous
That's where they live, that's where they colonize,
that's where they can actually be acquired from to create
Importantly, the Haemophilus require either hemin factor X
or factor V for growth. .
This factor is present in chocolate agar which is the most
typical way of growing Haemophilus influenzae.
However, to grow Haemophilus on blood agar, one also has to
grow staphylococcus aureus.
readily on chocolate agar, which is
essentially a blood agar with lysed red blood
cells. The reason for this is that standard
blood agar lacks the NAD
required to culture h flu.
Interestingly, however, you can co culture
staph aureus and h flu together on
routine blood agar because the staff
organism actually produces NAD as a metabolic
byproduct and the h flu can then grow as
satellite colonies in that
space created by the staph aureus.
This is demonstrated by the picture on the
right side of the slide where staph aureus is
streaked out that that line across the
middle of the blood agar.
And you can see Haemophilus influenza as
point satellite colonies growing right close
The medically relevant species we will talk about with
are Haemophilus influenzae and Haemophilus ducreyi.
Now, Haemophilus influenzae sure sounds a lot like
the virus which we know about causing the flu.
And in fact for the longest time historically, the illness
which we know as influenza was thought to be caused by a
bacteria which was the Haemophilus.
Hence, it took its name from the historical disease
We now know that of course bacterial disease caused by
does not cause the flu at all, but it can cause secondary