About 10% of latent infections progress to active disease which, if left untreated, kills about half of those affected. Over 400,000 new cases of mdrtb occur each year and, although their rates. Extensively drugresistant tuberculosis an isolation order, public health powers, and a global crisis howard markel, md, phd lawrence o. Surveillance of extensively drugresistant tuberculosis in europe. Multidrug and extensively drugresistant tuberculosis. Tuberculosis tb is an infectious disease usually caused by mycobacterium tuberculosis mtb bacteria. Key problems include the limited availability of effective drugs, the reduced efficacy of secondline drugs, an increased number of adverse reactions to. Extensively drugresistant tuberculosis xdr tb occurs when a mycobacterium tuberculosis strain becomes resistant to the firstline antitb drugs isoniazid and rifampin, plus any fluoroquinolone and at least one of the three secondline injectable drugs. Who recommends contact investigation in close contacts of patients with mdr. Multidrugresistant tuberculosis mdrtb is a form of tuberculosis tb infection caused by bacteria that are resistant to treatment with at least two of the most powerful firstline antitb medications drugs, isoniazid and rifampin. Who companion handbook to the who guidelines for the. Worldwide emergence of extensively drugresistant tuberculosis.
Revised definition of extensively drugresistant tuberculosis. Extensively drugresistant tuberculosis xdrtb is a form of tuberculosis caused by bacteria that are resistant to some of the most effective antitb drugs. Extensively drug resistant tuberculosis an overview. A total of 84 countries have reported cases of extensively drugresistant tuberculosis, a subset of multidrugresistant tuberculosis with added resistance to all fluoroquinolones plus any of the three injectable antituberculosis drugs, kanamycin, amikacin, and capreomycin. Tuberculosis tb is a disease caused by bacteria that are spread from person to person through the air. Clinical and operational value of the extensively drug.
Definition of extensively drugresistant tuberculosis. Preextensively drug resistant tuberculosis prexdrtb. Who consolidated guidelines on drugresistant tuberculosis. Pdf cdc pdf 37k multidrug resistant tuberculosis mdr tb what is tuberculosis tb.
In a report published on march 24, 2006, mmwr reported that cdc, in collaboration with the world health organization who and participating supranational reference laboratories, had agreed to define extensively drugresistant tuberculosis xdr tb as cases of tb disease in persons whose mycobacterium tuberculosis isolates were resistant to isoniazid and. A public health strategy of universal dst, meaning testing all patients with. Prexdrtb and resistance to both fqs and slis is defined. In 2006, the first reports of extensively drug resistant tuberculosis xdrtb, an even more severe form of drug resistant tb than multidrug resistant tb mdrtb, began to appear. The incidence of drug resistant tb has increased since the introduction of streptomycin, the first anti tuberculosis drug. Tuberculosis burden in households of patients with multidrugresistant and extensively drugresistant tuberculosis.
Companion handbook to the who guidelines for the programmatic management of drug resistant tuberculosis. Tb usually affects the lungs, but it can also affect other parts of the body, such as the brain, the kidneys, or the spine. We surveyed the network of supranational reference laboratories for m. Most infections do not have symptoms, in which case it is known as latent tuberculosis. Resistance to tuberculosis tb drugs is a formidable obstacle to effective tb care and prevention globally.
Tuberculosis generally affects the lungs, but can also affect other parts of the body. The latest estimates based on survey data report that 11. Revised definition of extensively drugresistant tuberculosis in a report published on march 24, 2006, mmwr reported that cdc, in collaboration with the world health organization who and participating supranational reference laboratories, had agreed to define extensively drug resistant tuberculosis xdr tb as cases of tb disease in persons whose mycobacterium tuberculosis. Tb with additional bacillary resistance to any fluoroquinolone and at least one of the three second. Context worldwide emergence of extensively drugresistant tuberculosis xdrtb has raised global public health concern, given the limited therapy options and high mortality objectives to describe the epidemiology of xdrtb in the united states and to identify unique characteristics of xdrtb cases compared with multidrugresistant tb mdrtb and drugsusceptible tb cases. Xdrtb extensively drugresistant tuberculosis abbreviations of tb agents am amikacin amxclv amoxicillinclavulanic acid bdq bedaquiline cfz clofazimine cm capreomycin cs cycloserine dlm delamanid e ethambutol eto ethionamide gfx gatifloxacin hh highdose isoniazid impcln imipenemcilastatin km kanamycin. Mdrtb strains with additional resistance to secondline drugs were described as extensively drug resistant tb xdr. Treatment outcomes for hivuninfected patients with. The emergence of multidrug resistant tuberculosis mdrtb and, more recently, extensively drug resistant tb xdrtb is widely considered a serious threat to global tb control. Extensively drugresistant tb xdrtb is defined as tb caused by a multidrugresistant mdr strain ie, resistant to at least rifampicin and.
Clinical and operational value of the extensively drugresistant tuberculosis definition. Extensively drugresistant tuberculosis sciencedirect. Extensively drugresistant tb xdrtb is defined as tb caused by a multidrugresistant mdr strain ie, resistant to at least rifampicin and isoniazid that is also resistant to any fluoroquinolone fq and any of the secondline injectable drugs, such as capreomycin, kanamycin, or amikacin. Extensively drugresistant tb xdr tb extensively drugresistant tb xdr tb is a rare type of mdr tb that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable secondline drugs i. Definition of extensively drugresistant tuberculosis in the dictionary. Extensively drugresistant tb xdr tb is a rare type of multidrugresistant tuberculosis mdr tb that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable secondline drugs i. The worldwide emergence of extensively drugresistant tuberculosis xdr tb and a provisional definition for this form of tb were first reported in november 2005. Multidrugresistant tuberculosis is defined as infection caused by mycobacterium tuberculosis resistant to isoniazid and rifampin the core drugs for tb treatment. People who have multidrugresistant tb mdrtb are at high risk for treatment failure. Multidrugresistant mdr and extensively drugresistant xdr tuberculosis have emerged as major global health threats. Cases of multidrugresistant tuberculosis mdrtb appeared after the widespread use of rifampicin from the 1970s onward. Mdrtb in addition to resistance to any fluroquinolones and at least one of three injectable secondline drugs, namely. Extensively drug resistant tuberculosis as a cause of death in patients coinfected with tuberculosis and hiv in a rural area of south africa.
A survival guide for clinicians, third edition was created through a collaboration of the curry international tuberculosis center citc and the state of california department of public health, tuberculosis control branch cdph. Multidrugresistant tuberculosis and extensively drugresistant. Multidrug resistant mdr isolates are prevalent in parts of asia and africa and are often associated with the dominant h58 haplotype. The definition has applicable clinical value and has allowed for more uniform surveillance in varied international. A form of tuberculosis tb that is resistant to at least the two most effective tb drugs isoniazid and rifampin. Multidrug and extensively drugresistant mycobacterium. Extensively drugresistant tuberculosis xdrtb appeared following the misuse of secondline drugs.
Extensively drug resistant tuberculosis xdrtb appeared following the misuse of secondline drugs. Multidrugresistant mdr and extensively drugresistant xdr tuberculosis tb is an emerging threat to tb control in ukraine, a country with the third highest xdr tb burden globally. Extensively drugresistant tb xdrtb is defined as tb due to bacilli resistant to any fluoroquinolone, and at least one of three injectable secondline drugs capreomycin, kanamycin, and amikacin, in addition to isoniazid and rifampicin. Who treatment guidelines for drug resistant tuberculosis. This study determined treatment outcomes among a cohort of mdrtb and xdrtb patients in hunan. In subsaharan africa, for example, in the absence of systematic use of antiretroviral drugs, even the best dots programme cannot achieve better results than.
Revising the definition of extensively drugresistant. Extensively drugresistant tuberculosis among multidrugresistant tuberculosis isolates, by region, 20002004 in evaluating the accuracy of secondlinedrug susceptibility testing, we found that 7 0. This study was carried out to detect preextensively drug resistant tb prexdrtb cases among the multidrug resistant tb mdrtb patients in bangladesh, as the early detection of prexdrtb can guide clinicians in the appropriate modification of mdrtb. Extensively drugresistant tuberculosis as a cause of death in patients coinfected with tuberculosis and hiv in a rural area of south africa. It is resistant to almost all drugs used to treat tb, including the two best firstline drugs. A relatively rare type of multidrugresistant tuberculosis mdrtb. Extensively drugresistant tuberculosis xdrtb is defined as tuberculosis caused by a mycobacterium tuberculosis strain that is resistant to at least rifampicin and isoniazid among the firstline antitubercular drugs multidrugresistant tuberculosis. Extensively drugresistant tb was defined initially as infection caused by m. What is the prevalence of extensively drugresistant. This is cause enough for concern as multidrug resistant tuberculosis has a worse outcome and its management is very difficult even in high resource settings. Citc is a project of the university of california, san francisco, funded by the centers for.
Drugresistant tuberculosis tb has emerged as a significant global epidemic and poses a serious threat to hivinfected persons. Multidrugresistant mdr tuberculosis tb is more difficult to treat than is drugsusceptible tb. Extensively drugresistant tuberculosis xdrtb is defined as resistance to at least rifampin r and isoniazid h. Emergence of new forms of totally drugresistant tuberculosis bacilli.
Swendiman and nancy lee jones legislative attorneys american law division summary the recent international saga of a traveler with xdrtb, a drugresistant form of tuberculosis, has placed a spotlight on existing mechanisms to contain contagious. We used wholegenome sequencing of a convenience sample to identify bacterial genetic and patientrelated factors associated with mdrxdr tb in this country. Information and translations of extensively drugresistant tuberculosis in the most comprehensive dictionary definitions resource on the web. Revised definition of extensively drugresistant tuberculosis in a report published on march 24, 2006, mmwr reported that cdc, in collaboration with the world health organization who and participating supranational reference laboratories, had agreed to define extensively drugresistant tuberculosis xdr tb as cases of tb disease in persons whose mycobacterium tuberculosis.
Treatment of drugresistant tuberculosis resistance to tuberculosis tb drugs is a formidable obstacle to effective tb care and prevention globally. The worldwide emergence of multidrugresistant tuberculosis mdrtb and extensively drugresistant tuberculosis xdrtb has posed additional challenges for global tuberculosis tb control efforts, as limited treatment options are available and treatment outcomes are often suboptimal. Summaries of unpublished data used for the recommendations 1. Outcomes for individuals with extensively drug resistant tuberculosis xdrtb are worse as reported by who in 2017, only 30% of patients were successfully. Extensively drugresistant xdr tb refers to mdrtb strains that are. Extensively drug resistant tb xdr tb is a rare type of multidrug resistant tuberculosis mdr tb that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable secondline drugs i. Who estimated that in 2017, 460 000 people developed multidrugresistant mdr tuberculosis, defined by bacillary resistance to rifampicin and isoniazid, the two most effective firstline antitb drugs. Extensively drugresistant tuberculosis xdr tb is a relatively rare type of multidrugresistant tuberculosis mdr tb. Xdrtb strains have arisen after the mismanagement of individuals with multidrugresistant tb mdrtb almost one in four people in the world is infected with tb bacteria. The continuing spread of drugresistant tuberculosis tb is one of the most urgent. Who treatment guidelines for drugresistant tuberculosis, 2016 update. Treatment outcomes of patients with multidrugresistant. This extensively drugresistant tuberculosis xdrtb was originally defined by the us centers for disease control and prevention and who in 2006 as isolates with resistance to isoniazid and rifampicin, and at least three of the six main classes of secondline agents.
Cases of multidrug resistant tuberculosis mdrtb appeared after the widespread use of rifampicin from the 1970s onward. See text for the definition of the shorter mdrtb treatment regimen, and for other. Xdr tb is also resistant to the best secondline medications. The incidence of drugresistant tb has increased since the introduction of streptomycin, the first antituberculosis drug. Mycobacterium tuberculosis strains that are resistant to an increasing number of secondline drugs used to treat multidrugresistant tuberculosis mdrtb are becoming a threat to public health worldwide. Extensively drugresistant tuberculosis in the united. Extensively drugresistant 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 secondline drugs amikacin, capreomycin, or kanamycin.
Emergence of an extensively drugresistant salmonella. Pdf the problem of drugresistant tuberculosis tb is growing in several hot spots throughout. Pdf cdc pdf 421k extensively drugresistant tuberculosis xdr tb what is extensively drugresistant tuberculosis xdr tb. Some forms of tb are also resistant to secondline medications, and are called extensively drugresistant tb. What does extensively drugresistant tuberculosis mean. Reduced susceptibility to fluoroquinolones is also widespread, and sporadic cases of resistance to thirdgeneration cephalosporins or azithromycin. Extensively drugresistant tuberculosis xdrtb definition. Antibiotic resistance is a major problem in salmonella enterica serovar typhi, the causative agent of typhoid. Multidrugresistant tuberculosis and extensively drugresistant tuberculosis.
Only when the bacteria become active do people become ill with tb. Reports of extensively drugresistant xdr tb, defined as mdr tb with. Multidrug and extensively drugresistant tb world health. In 2006, there were an estimated 489,000 new cases of multidrugresistant mdr tbwhich is tb that is resistant to at least isoniazid and rifampinand 116,000 estimated deaths. Emergence of drug resistant tuberculosis tb is a major obstacle in the tb control programme of bangladesh. Extensively drugresistant tuberculosis xdr tb is defined as. Clinical and operational value of the extensively drugresistant tuberculosis definition article pdf available in european respiratory journal 304. What is extensively drugresistant tuberculosis xdr tb extensively. Fact sheets extensively drugresistant tuberculosis xdr tb tb. Extensively drugresistant tuberculosis xdrtb is an emerging health. Surveys are discrete studies measuring drug resistance among a speciallydesigned sample of tb. This definition was subsequently revised later in the same year to take.
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