Clinical and operational value of the extensively drug-resistant tuberculosis definition

Abstract

Currently, no information is available on the effect of resistance/susceptibility to first-line drugs different from isoniazid and rifampicin in determining the outcome of extensively drug-resistant tuberculosis (XDR-TB) patients, and whether being XDR-TB is a more accurate indicator of poor clinical outcome than being resistant to all first-line anti-tuberculosis (TB) drugs.To investigate this issue, a large series of multidrug-resistant TB (MDR-TB) and XDR-TB cases diagnosed in Estonia, Germany, Italy and the Russian Federation during the period 1999-2006 were analysed. Drug-susceptibility testing for first-and second-line anti-TB drugs, quality assurance and treatment delivery was performed according to World Health Organization recommendations in all study sites.Out of 4,583 culture-positive TB cases analysed, 361 (7.9%) were MDR and 64 (1.4%) were XDR. XDR-TB cases had a relative risk (RR) of 1.58 to have an unfavourable outcome compared with MDR-TB cases resistant to all first-line drugs (isoniazid, rifampicin ethambutol, streptomycin and, when tested, pyrazinamide), and an RR of 2.61 compared with ''other'' MDR-TB cases (those susceptible to at least one first-line anti-TB drug among ethambutol, pyrazinamide and streptomycin, regardless of resistance to the second-line drugs not defining XDR-TB).The emergence of extensively drug-resistant tuberculosis confirms that problems in tuberculosis management are still present in Europe. While waiting for new tools which will facilitate management of extensively drug-resistant tuberculosis, accessibility to quality diagnostic and treatment services should be urgently ensured and adequate public health policies should be rapidly implemented to prevent further development of drug resistance.

Treatment Outcomes of Patients with Multidrug-Resistant Tuberculosis (MDR- TB) Compared with Non-MDR-TB Infections in Peninsular Malaysia

“…Table 2 presents the poor treatment outcomes of MDR-TB patients. The overall treatment success rate in this study for MDR-TB patients was 17.1%, which is lower than the reported success rates in European and South Korean studies (39%-54%) (17,18). MDR-TB occurrence in different parts of the world is an alarming phenomenon because of the poor therapeutic outcomes obtained when isolated strains were resistant to INH and RIF (9,19).…”

“…XDR-TB, a subset of MDR-TB is resistant to RIF, INH, any fluoroquinolone, and at least one of three injectable drugs (i.e., capreomycin, kanamycin, or amikacin) (4,5). According to the WHO (2013), at least one case of XDR-TB was reported in 92 countries at the end of 2012.…”

Multidrug- and Extensively Drug-Resistant Tuberculosis, Germany

“…In infections with MDR TB, drug resistance to additional fi rst-line drugs other than isoniazid and rifampin has recently been shown to be a predictor of negative treatment outcomes (13). Resistance to fl uoroquinolones and injectable secondline drugs (capreomycin in particular) also contributes to increased risk for treatment failure and death in these cases (23,24).…”

Multi-drug resistant tuberculosis and HIV-infection

“…• полирезистентность -устойчивость более чем к 1 препарату, кроме сочетания изониазида и ри фампицина; • множественная ЛУ (МЛУ) -устойчивость к соче танию изониазида и рифампицина, независимо от наличия резистентности к другим препаратам; • обширная, или широкая ЛУ (ШЛУ) включает в себя устойчивость МБТ к изониазиду, рифампи цину, фторхинолону и 1 из 3 инъекционных ПТП (канамицину, амикацину или капреомицину) [2]. Появлению туберкулеза с МЛУ (МЛУ туберкулез) в начале 1990 х гг.…”