Dynamic imaging in patients with tuberculosis reveals heterogeneous drug exposures in pulmonary lesions.

Tuberculosis (TB) is the leading cause of death from a single infectious agent, requiring at least 6 months of multidrug treatment to achieve cure1. However, the lack of reliable data on antimicrobial pharmacokinetics (PK) at infection sites hinders efforts to optimize antimicrobial dosing and shorten TB treatments2. In this study, we applied a new tool to perform unbiased, noninvasive and multicompartment measurements of antimicrobial concentration-time profiles in humans3. Newly identified patients with rifampin-susceptible pulmonary TB were enrolled in a first-in-human study4 using dynamic [11C]rifampin (administered as a microdose) positron emission tomography (PET) and computed tomography (CT). [11C]rifampin PET-CT was safe and demonstrated spatially compartmentalized rifampin exposures in pathologically distinct TB lesions within the same patients, with low cavity wall rifampin exposures. Repeat PET-CT measurements demonstrated independent temporal evolution of rifampin exposure trajectories in different lesions within the same patients. Similar findings were recapitulated by PET-CT in experimentally infected rabbits with cavitary TB and confirmed using postmortem mass spectrometry. Integrated modeling of the PET-captured concentration-time profiles in hollow-fiber bacterial kill curve experiments provided estimates on the rifampin dosing required to achieve cure in 4 months. These data, capturing the spatial and temporal heterogeneity of intralesional drug PK, have major implications for antimicrobial drug development.

Implementing a large-scale systematic tuberculosis screening program in correctional facilities in South Africa.

Background. Tuberculosis (TB) prevalence is high in correctional facilities in southern Africa. With support from local South African nongovernmental organizations, the South African Department of Correctional Services initiated a program of systematically screening newly admitted and current inmates for symptoms followed by GeneXpert Mycobacterium tuberculosis (MTB)/rifampicin (Rif) for microbiologic testing of symptomatic inmates. Methods. We conducted a program evaluation during a 5-month window describing program reach, effectiveness, adoption within the facilities, cost, and opportunities for sustainability. This evaluation included 4 facilities (2 large and 2 smaller) with a total daily census of 20 700 inmates. Results. During the 5-month evaluation window from May to September 2013, 7426 inmates were screened at the 4 facilities. This represents screening 87% of all new admits (the remaining new admits were screened by correctional staff only and are not included in these statistics) and 23% of the daily inmate census, reaching 55% of the overall screening target as calculated per annum. The reach ranged from 57% screened during these 5 months at one of the smaller facilities to 13% at the largest facility. Two hundred one cases of pulmonary TB were diagnosed, representing 2.1% of the screened population; 93% had documented initiation of TB treatment. The cost per TB case identified was $1513, excluding treatment costs (with treatment costs it was $1880). Conclusions. We reached a large number of inmates with high-volume screening and effectively used GeneXpert MTB/Rif to diagnose pulmonary TB and rapidly initiate treatment. The cost was comparable to other screening programs.