Haemophilus influenzae blood cultures

[gy8s]

Hi all,

Just wondering if anyone has experience growing H. influenzae in blood culture bottles?

My lab has been trying to crack this issue for some time.

We can grow it up using standard protocols without issue, however every time we attempt to spike it into blood culture bottles, our system reports them as negative after 5-7 days.

We've tried increasing inoculum concentration up to ~3,000,000 CFU/ml, trying different blood sample types (fresh, freeze/thawed, every anticoagulant under
the sun), trying all bottle types (aerobic, anaerobic, with and without exchange resins), trying different strains.

Even when we supplement the bottles with a Factor V/X growth supplement (Lysed horse blood) we can't detect it.

Is it possible there's some key variable we've overlooked?

Thanks

[CharonY]

Was CO2 controlled?