It has been a while since you have posted your question. I have noticed that
you have used positive and negative controls in your experiment in
BactiAlert system. What organisms did you use for this? I have looked into
vendor's site and could not find any recommendation. I'll appreciate your
help in this regard. Thank you in advance.
Marlborough, MA 01752
Could anyone provide some advice for a novice microbiologist about a
Staphylococcal isolate? The blood cultures were collected into a FAN bottle
(The patient had recently received antibiotics). BacTiAlert signalled
positive six days after the blood culture was collected. Gram positive
cocci were seen. Slide coagulase was positive. A thermonuclease was set up
directly from the blood culture bottle. It was negative at 4 hours, and
remained negative. Positive and negative controls worked well. A tube
coagulase was set up, and was positive, so we were happy to call this S.
aureus. Interestingly the thermonuclease was positive from colonies growing
My question is why was the direct thermonuclease negative? Also why did the
BactiAlert take six days to signal positive? (I presume the answer to the
second question is that the patient was on antibiotics).