2009泛耐药结核综述

David

The Lancet Infectious Diseases
Volume 9, Issue 1, January 2009, Pages 19-30
Review
Extensively drug-resistant tuberculosis
泛耐药结核综述
Mandeep Jassal MDa and Prof William R Bishai MDb, ,

aDepartment of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD, USA

bDepartment of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA


Available online 5 November 2008.

Summary
Extensively drug-resistant (XDR) tuberculosis is defined as disease caused by Mycobacterium tuberculosis with resistance to at least isoniazid and rifampicin, any fluoroquinolone, and at least one of three injectable second-line drugs (amikacin, capreomycin, or kanamycin). The definition has applicable clinical value and has allowed for more uniform surveillance in varied international settings. Recent surveillance data have indicated that the prevalence of tuberculosis drug resistance has risen to the highest rate ever recorded. The gold standard for drug-susceptibility testing has been the agar proportion method; however, this technique requires several weeks for results to be determined. More sensitive and specific diagnostic tests are still unavailable in resource-limited settings. Clinical manifestations, although variable in different settings and among different strains, have in general shown that XDR tuberculosis is associated with greater morbidity and mortality than non-XDR tuberculosis. The treatment of XDR tuberculosis should include agents to which the organism is susceptible, and should continue for a minimum of 18–24 months. However, treatment continues to be limited in tuberculosis-endemic countries largely because of weaknesses in national tuberculosis health-care models. The ultimate strategy to control drug-resistant tuberculosis is one that implements a comprehensive approach incorporating innovation from the political, social, economic, and scientific realms.

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xtensively Drug-Resistant Tuberculosis in the United States, 1993-2007
N. Sarita Shah, MD, MPH; Robert Pratt, BS; Lori Armstrong, PhD; Valerie Robison, DDS, MPH, PhD; Kenneth G. Castro, MD; J. Peter Cegielski, MD, MPH
JAMA. 2008;300(18):2153-2160.
Context  Worldwide emergence of extensively drug-resistant tuberculosis (XDR-TB) has raised global public health concern, given the limited therapy options and high mortality.
Objectives  To describe the epidemiology of XDR-TB in the United States and to identify unique characteristics of XDR-TB cases compared with multidrug-resistant TB (MDR-TB) and drug-susceptible TB cases.
Design, Setting, and Patients  Descriptive analysis of US TB cases reported from 1993 to 2007. Extensively drug-resistant TB was defined as resistance to isoniazid, a rifamycin, a fluoroquinolone, and at least 1 of amikacin, kanamycin, or capreomycin based on drug susceptibility test results from initial and follow-up specimens.
Main Outcome Measures  Extensively drug-resistant TB case counts and trends, risk factors for XDR-TB, and overall survival.
Results  A total of 83 cases of XDR-TB were reported in the United States from 1993 to 2007. The number of XDR-TB cases declined from 18 (0.07% of 25 107 TB cases) in 1993 to 2 (0.02% of 13 293 TB cases) in 2007, reported to date. Among those with known human immunodeficiency virus (HIV) test results, 31 (53%) were HIV-positive. Compared with MDR-TB cases, XDR-TB cases were more likely to have disseminated TB disease (prevalence ratio [PR], 2.06; 95% confidence interval [CI], 1.19-3.58), less likely to convert to a negative sputum culture (PR, 0.55; 95% CI, 0.33-0.94), and had a prolonged infectious period (median time to culture conversion, 183 days vs 93 days for MDR-TB; P < .001). Twenty-six XDR-TB cases (35%) died during treatment, of whom 21 (81%) were known to be HIV-infected. Mortality was higher among XDR-TB cases than among MDR-TB cases (PR, 1.82; 95% CI, 1.10-3.02) and drug-susceptible TB cases (PR, 6.10; 95% CI, 3.65-10.20).
Conclusion  Although the number of US XDR-TB cases has declined since 1993, coinciding with improved TB and HIV/AIDS control, cases continue to be reported each year.
Author Affiliations: Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia. Dr Shah is now with the Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.

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alf of extensively drug-resistant TB patients die
Thu Nov 6, 2008 12:25am EST By Will Dunham
WASHINGTON (Reuters) - The hardest-to-treat form of tuberculosis kills half the people who get it, according to a South Korean study that is one of the few to track survival rates from the condition called extensively drug-resistant TB.
Tuberculosis is an infectious bacterial disease typically attacking the lungs. Increasing numbers of cases of TB that defy standard medical treatment are appearing worldwide.
The study tracked 1,407 patients with two categories of TB: multidrug resistant TB, or MDR-TB, which resists at least one of the two main TB drugs, and extensively drug-resistant TB, or XDR-TB, which defies nearly all drugs used to treat TB.
Forty-nine percent of those with XDR-TB died compared to 19 percent of patients with ordinary MDR-TB, researchers led by Dr. Tae Sun Shim of Asan Medical Center in Seoul wrote on Thursday in the American Journal of Respiratory and Critical Care Medicine.
The patients were diagnosed between 2000 and 2002 and were followed for up to seven years, the researchers said. About 5 percent of the patients had XDR-TB.
D'Arcy Richardson of the Seattle-based nonprofit group PATH, which supports public health efforts in about 70 nations, called the findings important. But she noted XDR-TB patients today likely would get more aggressive drug treatment than was given to the patients tracked in this study.
"We have so little information on XDR-TB to begin with," Richardson, who wrote a commentary with two other TB experts accompanying the study, said in a telephone interview.
Cases of drug-resistant tuberculosis are being recorded around the world at the highest rates ever, with parts of the former Soviet Union especially vulnerable, the U.N. World Health Organization said this year.
Such cases account for about 5 percent of the 9 million new TB cases annually, the WHO said. It said that 489,139 MDR-TB cases emerged in 2006, and about 40,000 were XDR-TB.
There has been scant scientific data on long-term survival rates from XDR-TB.
"We know that it's a very big problem in Eastern Europe. We know it's a very big problem in Asia, particularly in India and China, where they don't necessarily have large percentages of MDR and XDR but because of the size of the population with TB we have significant numbers," Richardson said.
TB killed 1.7 million people worldwide in 2006, the WHO said. It can be spread by breathing in air droplets from a cough or sneeze of an infected person.