viernes, 23 de diciembre de 2011

Controlling Drug-Resistant TB Where It Is Most Prevalent >> CDC - IRPB Update - TB Notes 4, 2011

CDC - IRPB Update - TB Notes 4, 2011

Controlling Drug-Resistant TB Where It Is Most Prevalent

The global emergence of new strains of TB that are resistant to conventional TB drugs is a serious threat to the goal of TB elimination. One of the regions with the highest incidence of drug-resistant TB is Central Asia. In Kazakhstan, which is in Central Asia, about 20% of new cases of TB are multidrug-resistant TB, or MDR TB, defined as TB that is resistant to the two main TB drugs, isoniazid and rifampin. In the United States, this rate is currently about 1%, but will increase if drug resistance rates continue to rise abroad. In Kazakhstan, MDR TB rates have increased steadily since 1997. In the United States, several recent MDR TB patients had contracted the disease in Central Asia.

MDR TB mostly develops as the result of doctors giving inappropriate treatment, or from patients missing doses or failing to complete a course of treatment. After the fall of the Soviet Union, health systems in former Soviet states such as Kazakhstan fell apart, and TB patients received partial and inappropriate antibiotic treatment. This current epidemic is the result of a fragmented TB system that lasted at least a decade starting with the 1991 dissolution of the Soviet Union. We are working to help rebuild this system.

DTBE projects in Kazakhstan, developed at the request and in collaboration with the Kazakhstan National TB program, include the following:
  1. An evaluation of the Kazakhstan Electronic National TB Registry (ETR), which was submitted as a report to the Ministry of Health by Drs. Matt Willis and Tim Holtz. Key findings included a lack of awareness among local TB controllers of the ETR functions designed for their local use, such as automated region-specific reports that track trends over time. Also, there was a lack of centralized epidemiologic, managerial, and information technology (IT) personnel for managing the large nationwide electronic surveillance network. The main recommendations related to enhanced training of peripheral TB controllers in ETR relevance for local application and strengthening central support for the ETR system as whole.
  2. An assessment of the risk factors for primary MDR TB, which was presented as a oral presentation at the UNION International meeting in Berlin November 2010; this is being written up as a manuscript by Drs. Matt Willis and Patrick Moonan. In the setting of limited lab capacity to perform drug-susceptibility testing (DST) for every TB case, this analysis was intended to offer recommendations for targeting those patients most likely to have MDR TB for available DST testing. We found that the prevalence of primary MDR TB is very high, with about 40% of all new cases demonstrating resistance to at least one of the 4 first-line drugs. There are few criteria that differentiated high-risk from low-risk patients—essentially the whole population of new TB patients must be considered to be at high risk for MDR TB. Therefore, we recommended scale up toward universal DST in Kazakhstan, rather than a targeted approach.
  3. Describing the epidemiology of TB/HIV in Kazakhstan was delivered as an oral presentation at the annual EIS conference in Atlanta in 2010; it is being written up as a manuscript by Drs. Matt Willis, Tim Holtz, and Patrick Moonan. HIV prevalence among TB patients in Kazakhstan is low, at 2%. However, the incidence is rising. This is especially concerning because of the high background incidence of MDR TB. We found patients with the combination of MDR TB/HIV had 37 times the mortality of those with TB alone. We found that the TB/HIV population remains relatively confined to a distinct group of male intravenous drug users in urban centers clustered along the heroin transit routes through northeast Kazakhstan. This description offers an opportunity for aggressive intervention toward this group to detect, treat, and control further spread of HIV within TB patients.
  4. We conducted Atlanta-based training of 10 TB controllers from Eastern Kazakhstan Oblast, the area with the highest rates of MDR TB, in developing and implementing an action plan to address the spread of drug-resistant TB locally (Drs. Matt Willis and Patrick Moonan).
Other DTBE work in Central Asian countries:
  1. Nationally representative anti-tuberculosis drug-resistance survey (DRS), Kyrgyzstan, 2010–2011 (Dr. Patrick Moonan)
  2. Nationally representative DRS, Tajikistan, 2010–2011 (Dr. Patrick Moonan)
  3. Nationally representative DRS, Ukraine, 2012–2013 (Dr. Patrick Moonan).
–Reported by Matt Willis, MD, MPH
and Patrick Moonan, PhD
Div of TB Elimination

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