Latent Tuberculosis in Psoriasis Patients on Biologic Therapies: Real-World Data from a Care Center in Romania.

Background and Objectives: Psoriasis is a chronic and inflammatory condition that has a huge impact on the patient's quality of life. Biological treatment improved psoriasis therapy, with impressive results seen in the evolution of the disease and the patient's quality of life. However, the risk of mycobacterium tuberculosis (MTB) infection reactivation is well-known to biological therapy, which raises problems especially in an endemic country. Materials and Methods: In this study, we followed moderate to severe psoriasis patients who had latent tuberculosis infection (LTBI) following treatment with a biological therapy approved in Romania. Results: The patients were evaluated at baseline and then followed-up with Mantoux tests and chest X-rays every year, resulting in 54 patients being diagnosed with LTBI. At the initial evaluation, 30 patients with LTBI were identified, and 24 more were identified during biological therapy. These patients were given prophylactic treatment. Out of the 97 participants in this retrospective study, 25 required association of methotrexate (MTX) alongside biological therapy. We compared the prevalence of positive Mantoux tests in patients with combined therapy with that of patients only on biological treatment, and the results were higher in the combined therapy group. Conclusion: All the patients in the study were vaccinated against tuberculosis (TB) after birth, and none were diagnosed with active tuberculosis (aTB) before or after the start of therapy according to the pulmonologist.

Approach to Latent Tuberculosis Infection Screening Before Biologic Therapy in IBD Patients: PPD or IGRA?

The use of biological agents for the treatment of chronic inflammatory conditions such as inflammatory bowel diseases (IBD) has been on the rise.1,2 Current biological therapies include antitumor necrosis factor-α (anti-TNF-α), anti-interleukin-12/23, and anti-integrin agents. Before initiation of biological drugs, screening for Mycobacterium tuberculosis infection is required to avoid reactivation or worsening of disease after immunosuppression. It has been shown that anti-TNF-α treated patients have a 14-fold increased risk of tuberculosis (TB) infection/reactivation compared with healthy controls.3 The methods for screening for TB have evolved over time and vary from region to region.

Fluoroquinolones for the treatment of latent Mycobacterium tuberculosis infection in liver transplantation.

Solid organ transplantation (SOT) is the best treatment option for end-stage organ disease. Newer immunosuppressive agents have reduced the incidence of graft rejection but have increased the risk of infection, particularly due to the reactivation of latent infections due to opportunistic agents such as Mycobacterium tuberculosis. Active tuberculosis (TB) after SOT is a significant cause of morbidity and mortality. Most cases of posttransplant TB are secondary to reactivation of latent tuberculosis infection (LTBI) due to the effects of long-term immunosuppressive therapy. Risk minimization strategies have been developed to diagnose LTBI and initiate treatment prior to transplantation. Isoniazid with vitamin B6 supplementation is the treatment of choice. However, liver transplantation (LT) candidates and recipients have an increased risk of isoniazid-induced liver toxicity, leading to lower treatment completion rates than in other SOT populations. Fluoroquinolones (FQs) exhibit good in vitro antimycobacterial activity and a lower risk of drug-induced liver injury than isoniazid. In the present review, we highlight the disease burden posed by posttransplant TB and summarize the emerging clinical evidence supporting the use of FQs for the treatment of LTBI in LT recipients and candidates.

Hyperbaric oxygen therapy increases the risk of tuberculosis disease.

BACKGROUND: As Mycobacterium tuberculosis is an aerobic microbe, hyperbaric oxygen therapy (HBOT) could trigger progression from latent tuberculous infection (LTBI) to active tuberculosis (TB) disease. OBJECTIVE: To evaluate the effect of HBOT on TB reactivation. DESIGN: Our study sample was from the National Health Insurance Research Database containing one million beneficiaries. We identified a group of patients who underwent HBOT, and matched this group with individuals without HBOT. We compared the incidence of activation of TB between these two groups. RESULTS: A total of 2258 patients were identified, with each group comprising 1129 patients. One year after exposure to hyperbaric oxygen, the number of cases of active TB was significantly higher in the HBOT group than in the non-HBOT group (11 cases vs. 1 case, P = 0.006). Multiple regression analysis showed that HBOT was the only statistically significant contributor to TB activation. CONCLUSION: HBOT is likely to trigger the reactivation of TB. High-risk patients should undergo the tuberculin skin test or interferon-gamma release assays before HBOT to identify patients with LTBI.

Outcomes of Treatment for Latent Tuberculosis Infection in Patients With Inflammatory Bowel Disease Receiving Biologic Therapy.

Background: Treatment for latent tuberculosis infection (LTBI) is of particular concern in patients with inflammatory bowel disease (IBD) initiating biologic therapies to prevent tuberculosis (TB) reactivation. This study aimed to evaluate the effectiveness of LTBI treatment in IBD patients receiving biologic therapy. Methods: There was a retrospective review of all IBD patients diagnosed with LTBI following a tuberculin skin test (TST) and/or interferon gamma release assay (IGRA) and who received biologic therapy between 2002 and 2016. The primary outcome was tuberculosis reactivation after completion of LTBI treatment. Results: Three-hundred twenty-nine IBD patients were identified, and 35 (27 Crohn's disease; 8 ulcerative colitis) met the study inclusion criteria. The mean age was 38.3 years, and 68.6% were male. The most common LTBI treatment regimen was isoniazid (INH) for 9 months (74%). Biologic therapies used were infliximab (40%), adalimumab (29%), vedolizumab (20%), and certolizumab pegol (11%). Combination therapy with an immunomodulator was administered in 57% of cases. The median time from initiation of LTBI treatment to biologics was 43 days. The mean duration of follow-up was 2.9 years. The estimated median annual risk of TB reactivation without treatment was 0.52% by a prediction formula. Only 1 patient taking adalimumab monotherapy developed reactivation of TB several years after completing 6 months of isoniazid therapy. The estimated TB reactivation rate was 0.98 cases per 100 patient-years of follow-up in our cohort. Conclusions: Treatment for LTBI in patients with IBD treated with biologics is effective but does not eliminate the risk of reactivation. 10.1093/ibd/izy133_video1izy133.video15776720675001.

Small-Molecule Probes Reveal Esterases with Persistent Activity in Dormant and Reactivating Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb) is the deadliest bacterial pathogen in the world. An estimated one-third of humans harbor Mtb in a dormant state. These asymptomatic, latent infections impede tuberculosis eradication due to the long-term potential for reactivation. Dormant Mtb has reduced enzymatic activity, but hydrolases that remain active facilitate pathogen survival. We targeted Mtb esterases, a diverse set of enzymes in the serine hydrolase family, and studied their activities using both activity-based probes (ABPs) and fluorogenic esterase substrates. These small-molecule probes revealed functional esterases in active, dormant, and reactivating cultures. Using ABPs, we identified five esterases that remained active in dormant Mtb, including LipM (Rv2284), LipN (Rv2970c), CaeA (Rv2224c), Rv0183, and Rv1683. Three of these, CaeA, Rv0183, and Rv1683, were catalytically active in all three culture conditions. Fluorogenic probes additionally revealed LipH (Rv1399c), Culp1 (Rv1984c), and Rv3036c esterase activity in dormant and active cultures. Esterases with persistent activity are potential diagnostic biomarkers or therapeutic targets for Mtb-infected individuals with latent or active tuberculosis.

Preventing tuberculosis in the foreign-born population of Canada: a mathematical modelling study.

BACKGROUND: Foreign-born persons in Canada contribute 67% of all tuberculosis (TB) cases annually, but represent only 21% of the total population. Molecular epidemiological studies suggest that most foreign-born TB cases result from the reactivation of latent tuberculous infection (LTBI) acquired before immigration. OBJECTIVE: To estimate the effect on incidence of a prevention strategy that would screen selected immigrants at arrival for LTBI and offer preventive treatment to those who test positive. DESIGN: A deterministic model was developed to quantify the incidence of active TB in immigrants to Canada and validated with national immigration and TB case data. RESULTS: Model simulations suggested that it would be optimal to screen and treat LTBI in new immigrants from countries of birth with an estimated TB incidence rate in excess of 50 per 100 000 person-years. If this strategy had been implemented in 1986, the national TB incidence rate would have fallen by 18.5%, from 5.4 to 4.4 cases per 100 000 population by 2002. CONCLUSION: This study suggests that screening and treating LTBI in foreign-born persons from high TB incidence countries is the most effective strategy in terms of total persons screened and treated and percentage reduction in national incidence.

In vitro and in vivo activities of three oxazolidinones against nonreplicating Mycobacterium tuberculosis.

Oxazolidinones represent a new class of antituberculosis drugs that exert their function by inhibiting protein synthesis. Here, we compared the activities of three oxazolidinones, linezolid, PNU-100480, and AZD5847, against latent tuberculosis using a simple model employing the streptomycin-starved Mycobacterium tuberculosis strain 18b. The in vitro drug susceptibility results showed that the three oxazolidinones had a bacteriostatic effect against actively growing bacilli but potent bactericidal activity against nonreplicating cells. In the murine model of latent infection with M. tuberculosis 18b, the efficacy of the three compounds varied greatly. Indeed, AZD5847 or its prodrug exhibited no activity or only modest activity, respectively, after 2 months of treatment, whereas both linezolid and PNU-100480 were effective against latent bacilli in mice and showed promising outcomes in combination therapy with rifampin. Moreover, the potency of PNU-100480 was significantly greater than that of linezolid, making it an attractive drug candidate in the development of new combination therapies for latent tuberculosis.

Thioridazine pharmacokinetic-pharmacodynamic parameters "Wobble" during treatment of tuberculosis: a theoretical basis for shorter-duration curative monotherapy with congeners.

Phenothiazines are being repurposed for treatment of tuberculosis. We examined time-kill curves of thioridazine and first-line drugs against log-growth-phase and semidormant bacilli under acidic conditions and nonreplicating persistent Mycobacterium tuberculosis. While both the potency and the efficacy of first-line drugs declined dramatically as M. tuberculosis replication rates decreased, those of thioridazine improved. The mutation prevalence to 3 times the thioridazine MIC was <1 × 10(-11), better than for ≥2 first-line drugs combined. Hollow fiber system studies revealed that the relationship between sterilizing effect and pharmacodynamic indices (PDI) was characterized by an r(2) of 0.88 for peak/MIC, an r(2) of 0.47 for the area under the concentration-time curve (AUC) to MIC, and an r(2) of 0.14 for the cumulative percentage of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (%TMIC) at the end of the first week. However, the PDI linked to effect "wobbled" as the duration of therapy increased, so that by the fourth week the r(2) was 0.88 for AUC/MIC, 0.78 for %TMIC, and 0.72 for peak/MIC. This "wobble" has implications on general pharmacokinetic/pharmacodynamic theory, whereby efficacy is linked to only one of the three PDIs in deterministic models. The potency changed 8.9-fold from the first to the fourth weeks. The non-protein-bound AUC/MIC associated with maximal kill at the end of therapy was 50.53 (protein binding = 99.5%). This thioridazine exposure was calculated to extinguish all three M. tuberculosis metabolic populations in human lungs in only 42.9 days of monotherapy. However, this concentration exceeds the 2- to 8-mg/liter thioridazine concentration in serum known to be lethal to humans. Therefore, the way forward for phenothiazine monotherapy that also reduces therapy duration is via synthesis of less toxic congeners.

[The model of resting forms of mycobacteria for testing of drugs for latent forms of tuberculosis].

The new model of obtaining of ovoid resting forms Mycobacterium smegmatis, which are morphologically different from vegetative (rod-like) cells, was developed. Ovoid forms were characterized by a drastically decreased level of metabolic activity, an increased stability to heat processing and antibiotics action, and also by prolonged (more than 2 months) storage time preserving colony-forming ability. Obtained resting forms of mycobacteria may be used in test-systems for checking efficiency of new medical agents against latent forms of tuberculosis and determination of role of these of those genes in entering rest state.