Both the Centers for Disease Control and National Jewish Medical and Research Center agreed upon the current diagnosis of multiple-drug resistant TB.

Our main point was that the distinction between XDR and MDR is one of degree, and not a huge one at that. However (and this could have been more explicit in our original report) the CDC and National Jewish do agree on the MDR diagnosis.

This is good news both for Andrew Speaker and for any persons who may have come in contact with him before his hospitalization.

We apologize for any confusion. We also wish Mr. Speaker the speediest possible recovery.

Perhaps the following excerpts from the press conference transcript will clarify our point:

UNIDENTIFIED PARTICIPANT: Mr. Speaker sounds terribly unhappy that he was misdiagnosed. The CDC is saying this was not a misdiagnosis, that it’s absolutely a serious disease, it’s not deadly, but it’s absolutely serious. Is there not a dispute over that point?

DALEY: … Mr. Speaker, of course, is not happy that he was diagnosed with XDR, when in fact, he has MDR and I think that’s a natural reaction from him.

There is no dispute in terms of the findings,because the CDC has found the same thing that we have. So we believe we’re all in agreement that we’re going to move forward with treatment for multi-drug resistance.

You said it wasn’t fatal but it is fatal. Multi-drug resistant TB is very difficult to treat. And remember that XDR TB is just a subset of multi- drug resistant TB. So this is still a serious disease. The cure rate is not… what we would expect with just standard TB therapy. It’s much more difficult, even if we do get to that cure rate.

So this is still a problem. I don’t think there’s dispute in terms of the diagnosis… Dr. Cohen, would you like to comment?

COHEN: Well, I agree with everything that you said….

The patient does have MDR TB, which is a very serious illness. As you pointed out, there [is] a larger percent[age] of people with MDR TB [who] die…. We always try to base our public health actions on the best available data. And when we find the strain of TB that’s multi-drug resistant, or XDR TB, we want to take the best public health actions to try not only to consider the aspects of the individual but also to protect the public.

Later in the press conference, when confronted more directly, the CDC representative seems to waffle on the subject of misdiagnosis. However, we think his point that MDR TB is still quite serious and not that different from XDR TB is well taken.

UNIDENTIFIED PARTICIPANT: Dr. Cohen, given the evidence you have before you today, would you characterize your initial diagnosis of Andrew Speaker as a misdiagnosis?

COHEN: The patient has multi-drug resistant TB. When we think of TB, there is an enormous difference between susceptible and multi-drug resistant TB. When we think about the difference between multi-drug resistant TB and XDR TB, there is a much smaller medical difference. But there is very little, if any, public health difference between XDR TB and MDR TB.

Later still in the press conference, Dr. Daley seems to come around to Dr. Cohen’s viewpoint regarding the distinctions between MDR and XDR:

DALEY: Since that first test by the CDC, all subsequent cultures… have found multi-drug resistant disease, not XDR…. Multi-drug resistant TB means resistance to isoniazid and rifampicin, our two best drugs.

You could also be resistant to six, seven, eight, nine more drugs but still not be called XDR TB…. Your strain is called an XDR TB strain if you have MDR TB—meaning isoniazid rifampicin resistance—plus resistance to at least two other drugs: fluoroquinolones, which are very potent drugs that are very helpful… and one of three injectibles that are also potent and very useful…

I think [when] you get down to these… subtleties it’s important to understand that the difference between MDR and XDR is… quite subtle in terms of the number of drugs.

So you could have six-drug resistant TB and not have XDR or you could have four-drug resistant TB and have XDR. The point is that… there’s not a lot difference between XDR and MDR TB in the sense that the public health response is the same no matter what.

It makes a big difference to me, as a clinician, however, because I can pick a number… of drugs… and… add them to the treatment regimen and improve the chance of cure.

So, from a clinical perspective this is important, from the public health perspective, no, there’s no real difference between MDR and XDR. Dr. Cohen, anything?

COHEN: I couldn’t have said it better, thank you.