TB: Stay vigilant as drug resistance spreads

Experts fear a return to complacency in U.S.

Tuberculosis has continued to decline in the United States even as parts of the world struggle with the growing burden of multi-drug resistant strains. Infectious diseases do not respect borders, however, so TB experts worry that complacency is as much the enemy as the disease.

"If we sit back and say 'problem solved,' we're deluding ourselves," says Peter Cegielski, MD, MPH, team leader for MDR-TB in the International Branch of the Centers for Disease Control and Prevention Division of TB Elimination.

History already has proven that point, with a resurgence of TB that occurred in the late 1980s and early 1990s. If anything, global travel is even greater than it was back then, while tuberculosis cases continue to grow. About one-third of the world's population has latent TB infection, and TB prevalence is high in some countries such as India, the Philippines, and South Africa. Meanwhile, the rate of decline in TB cases in the United States has slowed, CDC reports.

When travelers come to the United States — whether as tourists, on business, or as immigrants — "people bring with them their history of having been exposed to TB in their populations," Cegielski says. "What's going on in the rest of the world directly affects us in the United States."

Hospitals must remain vigilant to protect health care workers, he emphasizes. "Tuberculosis remains a significant threat to health care workers, out of proportion to the risk to the general population," he says.

From 2000 to 2008, there were 48 health care workers with multi-drug resistant TB and three with extensively drug-resistant TB.

"The biggest risk may be that we become victims of our success of controlling TB in this country by virtue of becoming complacent about infection control measures," he says. "In the same way we don't always wash our hands between every patient when we're in a hurry, we may not always put on a respirator when it's inconvenient. But we should. It's very important that facility leadership sets the example and expects their staff to adhere to policies and procedures that are in place."

California is a bellwether of tuberculosis in the United States, with about 2,500 cases a year. About 30 to 40 of those are multi-drug resistant cases, with up to three XDR-TB cases a year. Although those numbers have remained stable due to a continuing commitment to TB control, the state has detected an increase in the precursors to XDR-TB, says Jennifer Flood, MD, MPH, chief of surveillance and epidemiology in the Tuberculosis Control Branch of the California Department of Public Health in Richmond, CA.

"We do have a concern that our TB epidemic can evolve to a less treatable form of TB and we're monitoring that closely," she says. "At this point, we have a stable proportion of MDR-TB cases and XDR has not climbed."

In 2008, 83 California health care workers were diagnosed with active TB. Most were foreign-born and did not have known work-related exposures, but that underscores the importance of screening and treating latent infection, says Flood.

"It does remind us that health care workers can actually have TB," she says. "Screening of health care workers is important because it protects the patients they're caring for and gives them an opportunity to prevent [active] TB."

When patients come to the emergency room with a prolonged cough, that should trigger an evaluation for TB, she says.

Most cases of TB in the United States remain susceptible to first-line drugs. But drug-resistant strains will certainly continue to appear, and a failure to identify suspected cases of TB in hospitals could put health care workers at risk, says Cegielski.

To prevent nosocomial transmission, Cegielski and Flood advise that hospitals should:

Maintain a high level of suspicion of TB. During the peak of the novel H1N1 pandemic, emergency rooms across the country reacted with caution when patients arrived with a fever and respiratory symptoms. They were segregated and given a mask to wear, if practicable. That precaution should continue in ambulatory care and emergency rooms to prevent the spread of respiratory diseases, says Cegielski. "If someone comes in with a fever and cough, it shouldn't be only during influenza season that those individuals are placed in a separate waiting room," he says.

Provide feedback to staff about preventive measures. Feedback is the best way to encourage continued compliance with recommendations, he says. Possible data include the number of TB screenings, the number of TB conversions, or the use of respirators, he suggests. "Employee health practitioners could provide that information to the people they serve as well as to the administrators of the facility as a means of demonstrating the effectiveness of their activities," he says.

Ask about extended travel to TB-endemic countries. Health care workers who spend an extended amount of time in countries with a high rate of TB are at greater risk of acquiring the latent infection, as are foreign-born individuals. Annual questionnaires during TB screening or respirator fit-testing could simply ask employees if they had any potential community exposures, including travel to high-risk areas. For example, someone who spent time volunteering in Haiti might want to be screened before and after their trip and to bring fit-tested respirators for protection, Cegielski suggests.