Update on extensively drug-resistant tuberculosis

Since the first description and definition of extensively drug-resistant tuberculosis (XDR-TB) in 2007, it has been identified in most regions of the world with South Africa as the highest burden country. It is associated with a high mortality. In some instances, the Mycobacterium tuberculosis organism that is XDR is most likely acquired due to spontaneous chromosomal mutations. The KZN and Beijing strains of M. tuberculosis may be inherently virulent and/or possess a greater propensity to developing resistance. HIV infection per se is not a risk factor for acquisition. Remarkable strides in the last 5 years have seen advances in the diagnosis of XDR-TB, earlier detection and earlier institution of treatment, the fasttracking of the development of new anti-TB drugs, and testing of existing antibiotics as part of complex regimens of treatment. It is becoming apparent that the outbreak is declining in hot spots of the world and survival is improving. The outlook for cure of patients with XDR-TB for the majority is still bleak, as advances in diagnosis and treatment are generally inaccessible in resource-poor regions where the burden is greatest. Lack of optimal secondary chemoprophylaxis for XDR-TB contacts undermines TB control. National strategies to prevent the spread and elimination of XDR-TB must be founded on an overall TB control strategy defined by optimal treatment completion and cure rates, control of HIV infection, environmental infection control in health care settings and communities (contact tracing and early treatment of TB), increased capacity and expertise of health care systems, and socioeconomic improvement. The looming danger of totally drug-resistant TB as a natural progression of XDR-TB has already been identified in some regions of the world. Copyright © 2014 by Lippincott Williams &Wilkins.