XDR-TB Genome Sequencing: A Glimpse of the Microbiology of the Future

Abstract

Drug-resistant TB: a new scourge Extensively drug-resistant (XDR)-TB was first described in March 2006 by the US CDC and the WHO [1]. At first it was defined as resistance to isoniazid and rifampicin, as well as three of the six classes of second-line drugs, but more recently the definition has become more sophisticated [2]. An outbreak in September 2006 attracted the attention of the international medical community. A total of 53 cases of XDR-TB were confirmed in Tugela Ferry, a town in the South African province of KwaZulu-Natal. Of the patients tested, all were HIV positive. This strain was remarkably aggressive: median survival from the time of sputum collection was just 16 days [3]. XDR-TB has now been isolated on five continents. The first case to attract the attention of the mass media was the story of ‘the TB guy’. This high-profile incident in May 2007 involved Andrew Speaker, a personal-injury lawyer from Atlanta. Speaker took international flights – first to Greece to get married, then to Rome for his honeymoon before the CDC raised the suspicion that he was infected with XDR-TB. The CDC mounted a fraught operation to quarantine him in Europe and the media followed his every movement. Desperate to return to the US and unable to afford private airline travel, Speaker defied advice by returning to the US on a commercial airline. Although this action attracted fierce criticism, Speaker’s diagnosis was later confirmed as the more treatable multidrug-resistant (MDR)-TB [101].