Content area
Full Text
Figure 1. Current diagnostic paradigm for detection, identification and determination of drug resistance in Mycobacterium tuberculosis (left) versus a future paradigm envisioned to combine all aspects of testing into a single platform (right). HPLC: High performance liquid chromatography; MDR: Multidrug resistant; MTBC: Mycobacterium tuberculosis complex; TAT: Turn-around time.
(Figure omitted. See article PDF.)
""There is a gathering storm of drug-resistant tuberculosis"" and ""the strategy of the WHO and of other national and international health agencies ...... has failed to control the disease or prevent the emergence of more threatening strains that are extremely resistant to the antibiotics available today......"" [101].
The rising tide of drug-resistant TB
Tuberculosis is one of the oldest diseases known to man. Yet despite decades of medical advances, TB remains a major public health menace worldwide. We''ve all seen the numbers; two billion people, or one third of the world''s population, are infected with the causative agent, Mycobacterium tuberculosis [1--3]. More than nine million new cases of TB are reported each year, resulting in two million deaths [1,2]. Yet, written numbers alone do little to reflect the true human cost of this disease. Even more alarming has been the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) M. tuberculosis strains, which are rapidly becoming the next global health emergency and are the harbingers of an impending pandemic [4--9].
MDR-TB is defined as M. tuberculosis resistant to isoniazid and rifampin; XDR-TB is MDR, plus resistance to any fluoroquinolone and at least one of the injectable second-line drugs, amikacin, kanamycin or capreomycin [10]. Much of the drug resistance worldwide is the result of a complex interplay of a variety of factors ranging from inadequate to inappropriate therapy. Inadequate therapy is intricately linked to noncompliance, poor patient follow-up, inaccessibility of required drugs or use of substandard drugs, all of which strain local resources and hinder control efforts. Inappropriate therapy is often connected to diagnostic impediments related to identification of those with TB and in those who have been diagnosed, the failure to detect drug resistance. Failure to detect TB cases may also promote resistance to second-line agents should a misdiagnosis result in administration of a single antibiotic for a suspected bacterial infection, as with ciprofloxacin in the context of community-acquired pneumonia [11,12]. In...