A new round of tests show that Atlanta attorney Andrew Speaker may not be infected with the deadliest form of tuberculosis after all — but health officials maintain that they would have sounded the same public alarm.
The results of multiple tests suggest that the form of TB carried by Speaker may be the multidrug-resistant variety (MDR) rather than the extremely drug resistant (XDR) strain.
"Based on extensive testing of multiple isolates of organisms cultured from Mr. Speaker, we have been able to demonstrate that he does not have XDR tuberculosis," said Dr. Charles Daly, head of the National Jewish Hospital's infectious disease division, at a press conference Tuesday afternoon.
He said the new finding "allows us to change the way we treat him," adding that surgery will be put "on hold" for now while doctors try a strong antibiotic treatment regimen.
In a statement, Speaker said the tests vindicated him after news of his infection and subsequent airline flights prompted a public health scare.
"For the international panic that was created after my misdiagnosis and the way my case was handled, I can only hope that this news helps calm the fears of those people that were on the flights with me," Speaker wrote in a statement issued Tuesday.
But officials with the Centers for Disease Control and Prevention say they would have handled his case in the same way, regardless of whether initial tests revealed his strain to be MDR or XDR.
And it is unlikely that the change in classification from MDR to XDR will have much effect on those people Speaker shared an international flight with who were at risk of contracting his disease.
"In a sense, it is good for him, though I don't think it changes the picture for those potentially exposed," said Dr. Patricio Escalante, a tuberculosis expert at the Keck School of Medicine in Los Angeles.
"It was not certainly a tempest in a teapot, because exposure to, and potential transmission of, either MDR TB or XDR TB constitutes a serious public health event, requiring investigation and possibly prophylaxis of those infected," said Dr. Mario C. Raviglione, director of the Stop TB department of the World Health Organization.
"In other words, the change in resistance patterns only reduces slightly the seriousness of the case, which still represents a very severe risk for those potentially affected," said Raviglione.
Different Strain ... Same Response?
Three tests conducted at National Jewish Medical Center in Denver, Colo., showed that Speaker is, instead, infected with a strain resistant to many, but not all, antibiotic regimens. The results of these tests were announced at Tuesday's press conference.
CDC officials, however, are downplaying the differences between the two strains.
"If we were aware of a person with MDR TB, we would have recommended the same steps; we would have recommended that they not travel," said Dr. Mitchell Cohen, director of the CDC's Coordinating Center for Infectious Diseases, during Tuesday's press conference.
"Without question, people with these infections should not be flying on commercial airlines, and if they do, the CDC recommends follow-up and testing and testing of passengers," said Cohen.
According to CDC spokesperson Tom Skinner, the agency actively sought to contact Speaker and prevent him from traveling even before they believed he carried the XDR strain.
But he added that learning that Speaker may have been carrying the more deadly strain, increased the level of concern.
"Certainly, news that [we might be] dealing with XDR added a level of seriousness," Skinner said. "The fact that he had XDR ratcheted up the seriousness of our response."
He added, though, that the agency's response to the situation would have been no different in either case.
"The public health measures were in place prior to us being informed that it was XDR TB," Skinner said. "We may have been talking of mutant bacterial strain that we picked up. If they don't find it, it doesn't change the fact that there was XDR TB there."
Skinner said Speaker originally learned from health officials that he carried the MDR strain of the disease on May 10 and was urged at the time not to travel. The CDC took action on the case on May 18, Skinner said, and they contacted him by phone on May 22.
By this time, Speaker was in Rome, and CDC officials instructed him to turn himself in to Italian health authorities, Skinner said.
Instead, Speaker boarded another trans-Atlantic flight to Canada before entering the country through a checkpoint in Champlain, N.Y.
More Test Results to Come
Now, National Jewish Medical Center is testing the original culture examined by the CDC in March — the sample that the CDC used in their determination that Speaker's tuberculosis was the XDR version.
The results of this test will be available in about two weeks, said Daly. But the effort is stymied somewhat by the fact that, according to laboratory protocol, the original sample from which the culture was grown, was thrown away.
The new finding could have major implications for Speaker's prognosis; while XDR survival rates normally hover between 30 and 40 percent, those of MDR are around 70 percent.
But the fact remains that Speaker still requires significant medical attention.
"MDR bacteria remains difficult to treat," Cohen said, adding that those with the infection face two years of aggressive antibiotic therapies known for significant side effects.
The change from XDR to MDR also does not change Speaker's status at National Jewish Medical Center; he is still under order by Denver public health officials to remain at the hospital in isolation.
And disease experts say that it is still possible that both tests were actually accurate — that is, Speaker may have been infected with both the MDR and XDR strains.
"If that was a mutant that was there then, I don't know where it is now," Daly said. "We always base our clinical decisions on the predominant organism, which right now is MDR TB."
Cohen concurred. "In this patient, the predominant strain appears to be MDR tuberculosis."
Need for New Tests
In addition to changing Speaker's prognosis, it is possible that the diagnosis discrepancy could have implications other than those related to health.
"This saga is far from over, at least legally," said ABC News medical editor Dr. Timothy Johnson.
The difference in results also reveals the need for better testing methods.
"Misdiagnosis of XDR is possible, in view of the difficulties in lab tests today to declare the presence of resistance to second line drugs," Raviglione said.
"The whole issue of testing for TB is often a gray area," Johnson said. "There is not automatically a black or white result."