meeting in a series designed to gather information from experts around the world on the nature of this threat and how it can be addressed.2
The development of drug resistance is a predictable, natural phenomenon that occurs when microbes adapt to survive in the presence of drug therapy (Nugent et al., 2010). Although antibiotics developed in the 1950s are effective against a large percentage of TB cases, resistance to these first-line therapies has developed over the years, resulting in the growing emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB (see Box 1-1 for definitions). Workshop participants noted that the rapid spread of drug-resistant forms of TB poses new challenges to effective control of this disease, as diagnosing and effectively treating MDR/ XDR TB patients requires increasingly complex public health interventions. MDR TB, for example, is resistant to first-line drugs and must be treated with second-line drugs that are more expensive and more toxic, often require injection, and involve longer treatment regimens (2 years or more to treat MDR TB compared with 6–9 months to treat drug-susceptible TB). As drug resistance develops, the challenge is to preserve the effectiveness of current drugs and create new treatment regimens to combat resistant strains as they emerge.
During the workshop, Paul Farmer, founding director of Partners In Health, noted that although the advent of diseases such as drug-resistant TB, methicillin-resistant Staphylococcus aureus (MRSA), and extensively drug-resistant malaria was inevitable, it is possible to change the course of these epidemics and the rate at which acquired and transmitted resistance to the drugs used to treat those infected takes hold in a population.
Based on global drug resistance surveillance data from the World Health Organization (WHO), it is estimated that 3.6 percent of global TB cases, or a total of 440,000 cases, were MDR TB in 2008 (95 percent confidence interval, 390,000–510,000) (WHO, 2010b). However, a number of TB experts at this and prior workshops explained that available data on drug-resistant TB are inadequate and yield a gross underestimation of the true global burden of disease (see Chapter 2). Surveillance systems
2 The Drug Forum held a foundational workshop in Washington, DC, in 2008. The summary of that foundational workshop, Addressing the Threat of Drug-Resistant Tuberculosis: A Realistic Assessment of the Challenge: Workshop Summary, and the accompanying white paper (Keshavjee and Seung, 2008) provided background for and informed the development of and proceedings at the Russian Federation workshop summarized in this volume.