Primary Care Screening and Treatment for Latent Tuberculosis Infection in Adults

Mycobacterium tuberculosis Is Selectively Killed by Rifampin and Rifapentine in Hypoxia at Neutral pH

“…Two billion people are latently infected with this organism, and in 10% of them, it reactivates to active TB in their lifetime (1). Currently, treatments require 6 months of combination therapy with isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol for active TB and 9 months of INH or 3 months of rifapentine (RFP) and INH for latent TB (2,3). Active and latent TB infections comprise mixtures of cellular and caseous granulomas, with tubercle bacilli ranging from actively replicating (AR) to dormant nonreplicating (NR) stages (4).…”

“…In contrast, under conditions mimicking caseous granulomas (hypoxia at pH 7.3), only the rifamycins RIF and RFP rapidly killed NR M. tuberculosis, while all other lipophilic and Activity of Anti-TB Drugs in Hypoxia at Neutral pH Antimicrobial Agents and Chemotherapy hydrophilic drugs tested had no or little effect. RIF is known to accumulate and maintain therapeutic levels in caseum, where dormant M. tuberculosis resides (12,13), and a 3-month treatment of latent TB with RFP and INH was found to be noninferior to 9 months of INH treatment alone (3,14). Overall, our Wayne model experiment in hypoxia at pH 7.3 mimicking caseum may be important for testing the activity of new drugs and/or combinations against NR M. tuberculosis and guiding the selection of future therapies inhibiting the reactivation of latent TB to active TB.…”

Imaging manifestations of B-mode ultrasound combined with CT in tuberculous pleuritis patients and the diagnostic value

“…Clinical symptoms mainly included fever, the incidence among urban residents was higher than that among rural residents, and higher incidence was observed in smoking individuals. Possible explanations for these observations are: young and adult patients are more vulnerable to this disease due to the stronger response to the infection of tuberculosis bacilli compared with patients in other age groups (13); urban residents were exposed to harmful gases (factory emission, vehicle exhaust and passive smoking) and transmission of the tuberculous pleuritis is easier; for the smoking patients, nicotine, tar, carbon monoxide and other harmful gases may destroy the original immune system and the filtration system of the lungs, thus it is easier for the tuberculous bacillus to infect the cardio-pulmonary functions (14,15). The bacteriological culture examination cannot make the diagnosis to the pleurisy caused by the non-bacterial pathogen, therefore, the tuberculous pleurisy is generally excluded and needs to go through many examinations to confirm the pathological type.…”

The Challenge of Latent TB Infection

“…Thus, the USPSTF Recommendation Statement on screening in primary care settings for LTBI in adults and the accompanying Evidence Report and systematic review that provides support for the USPSTF recommendations, both of which are published in this issue of JAMA , are well timed. 9,10 …”

“…Risk assessment tools that have been developed by the CDC and the California Department of Public Health may be of use to clinicians in implementing the USPSTF recommendations. 14,15 The USPSTF notes that in the accompanying systematic review 9 there were insufficient data to make a recommendation for or against screening among persons with diabetes. Worldwide, especially in countries with high TB burden, diabetes and smoking are important risk factors.…”