Isoniazid

BackgroundTargeted preventive therapy for individuals at highest risk of incident tuberculosis might impact the epidemic by interrupting transmission. We tested performance of a transcriptomic signature of tuberculosis (RISK11) and efficacy of signature-guided preventive therapy in parallel, using a hybrid three-group study design.MethodsAdult volunteers aged 18-59 years were recruited at five geographically distinct communities in South Africa. Whole blood was sampled for RISK11 by quantitative RT-PCR assay from eligible volunteers without HIV, recent previous tuberculosis (ie, Findings20 207 volunteers were screened, and 2923 participants were enrolled, including RISK11-positive participants randomly assigned to 3HP (n=375) or no 3HP (n=764), and 1784 RISK11-negative participants. Cumulative probability of prevalent or incident tuberculosis disease was 0·066 (95% CI 0·049 to 0·084) in RISK11-positive (3HP negative) participants and 0·018 (0·011 to 0·025) in RISK11-negative participants (RR 3·69, 95% CI 2·25-6·05) over 15 months. Tuberculosis prevalence was 47 (4·1%) of 1139 versus 14 (0·78%) of 1984 in RISK11-positive compared with RISK11-negative participants, respectively (diagnostic RR 5·13, 95% CI 2·93 to 9·43). Tuberculosis incidence over 15 months was 2·09 (95% CI 0·97 to 3·19) vs 0·80 (0·30 to 1·30) per 100 person years in RISK11-positive (3HP-negative) participants compared with RISK11-negative participants (cumulative incidence ratio 2·6, 95% CI 1·2 to 5·9). Serious adverse events related to 3HP included one hospitalisation for seizures (unintentional isoniazid overdose) and one death of unknown cause (possibly temporally related). Tuberculosis incidence over 15 months was 1·94 (95% CI 0·35 to 3·50) versus 2·09 (95% CI 0·97 to 3·19) per 100 person-years in 3HP-treated RISK11-positive participants compared with untreated RISK11-positive participants (efficacy 7·0%, 95% CI -145 to 65).InterpretationThe RISK11 signature discriminated between individuals with prevalent tuberculosis, or progression to incident tuberculosis, and individuals who remained healthy, but provision of 3HP to signature-positive individuals after exclusion of baseline disease did not reduce progression to tuberculosis over 15 months.FundingBill and Melinda Gates Foundation, South African Medical Research Council.

The aim of the present work was to produce 3D-printed oral dosage forms with a sufficient drug dose displaying various release profiles. Hot-melt extrusion was utilized to produce drug-loaded feedstock material that was subsequently 3D-printed into 6, 8, and 10 × 2.5 mm tablets with 15% and 90% infill levels. The prepared formulations contained 30% (w/w) isoniazid in combination with one or multiple pharmaceutical polymers possessing suitable properties for oral drug delivery. Thirteen formulations were successfully hot-melt extruded of which eight had properties suitable for fused deposition modeling 3D printing. Formulations containing HPC were found to be superior regarding printability in this study. Filaments with a breaking distance below 1.5 mm were observed to be too brittle to be fed into the printer. In addition, filaments with high moisture uptake at high relative humidity generally failed to be printable. Different release profiles for the 3D-printed tablets were obtained as a result of using different polymers in the printed formulations. For 8 mm tablets printed with 90% infill, 80% isoniazid release was observed between 40 and 852 min. Drug release characteristics could further be altered by changing the infill or the size of the printed tablets allowing personalization of the tablets. This study presents novel formulations containing isoniazid for prevention of latent tuberculosis and investigates 3D printing technology for personalized production of oral solid dosage forms enabling adjustable dose and drug release properties.

India accounts for about one-fourth of the global burden of MDR-TB. This study aims to assess the prevalence and factors associated with tuberculosis drug resistance among patients from South India. MTBDRplus assay and MGIT liquid culture performed on 20,245 sputum specimens obtained from presumptive MDR-TB cases during a six-year period from 2013 to 2018 were analyzed retrospectively. Univariate and multivariate logistic regression analysis was carried out to evaluate factors associated with MDR, Rifampicin mono-resistance, and Isoniazid mono-resistance. MDR, Rifampicin mono- resistant and Isoniazid mono-resistant TB were found in 5.4%, 2.5%, and 11.4% cases of presumptive MDR-TB, respectively. Based on the rpoB gene, true resistance, hetero-resistance, and inferred resistance to Rifampicin was found in 38%, 29.3%, and 32.7% of the 1582 MDR cases, respectively. S450L (MUT3) was the most common rpoB mutation present in 59.4% of the Rifampicin resistant cases. Of the 3390 Isoniazid resistant cases, 72.5% had mutations in the katG gene, and 27.5% had mutations in the inhA gene. True resistance, heteroresistance, and inferred resistance accounted for 42.9%, 22.2%, and 17.3% of the 2459 katG resistant cases, respectively. True resistance, heteroresistance, and inferred resistance for the inhA gene were found in 54.5%, 40.7%, and 4.7% cases, respectively. MDR-contact (AOR 3.171 95% CI: 1.747-5.754, p-0.000) treatment failure (AOR 2.17595% CI: 1.703-2.777, p-0.000) and female gender (AOR 1.315 95% CI: 1.117-1.548, p-0.001), were positively associated with MDR-TB. Previous TB treatment did not show a significant positive association with MDR (AOR 1.113 95% CI: 0.801-1.546, p-0.523). Old age (AOR 0.994 95% CI: 0.990-0.999, p-0.023) and HIV seropositivity (AOR 0.580 95% CI: 0.369-0.911, p-0.018) were negatively associated with MDR-TB. Although Rifampicin mono-resistance had a positive association with treatment failure (AOR 2.509 95% CI: 1.804-3.490, p < .001), it did not show any association with previous TB treatment (AOR 1.286 95% CI: 0.765-2.164, p-0.342) or with history of contact with MDR-TB (AOR 1.813 95% CI: 0.591-5.560, p-0.298). However, INH mono-resistance showed a small positive association with the previous history of treatment for TB (AOR 1.303 95% CI: 1.021-1.662, p-0.033). It was also positively associated (AOR 2.094 95% CI: 1.236-3.548, p-0.006) with MDR-TB contacts. Thus INH resistance may develop during treatment if compliance has not adhered too and may be easily passed on to the contacts while Rifampicin resistance is probably due to factors other than treatment compliance. MDR-TB, i.e. resistance to both Rifampicin and Isoniazid, is strongly correlated with treatment failure, spread through contact, and not to treatment compliance. The temporal trend in this region shows a decrease in MDR prevalence from 8.4% in 2015 to 1.3% in 2018. A similar trend is observed for Rifampicin mono-resistance and Isoniazid mono-resistance, pointing to the effectiveness of the TB control program. The higher proportion of inferred resistance observed for Rifampicin compared with INH may indicate a surfeit of mechanisms that enable rifampicin resistance. Association of MDR-TB with age, gender, and HIV status suggest the role of the immune system in the emergence of the MDR phenotype.

The mutation S315T of the catalase-peroxidase (CP) protein KatG of Mycobacterium tuberculosis is the most common mutation that confers resistance to the prodrug isoniazid. Here, we reconstruct its evolutionary history in 145 whole-genome sequences of M. tuberculosis from Russian hospitals, inferring 11 independent appearances of this mutation and 5 reversion events, with an estimated reversion rate 1,500 times higher than the rate of preserved nonsynonymous or intragenic mutations. This suggests that, contrary to the commonly held view, the mutation KatG(S315T) results in a fitness cost, possibly because of reduced tolerance to oxidative stress. Consistent with this interpretation, the mutant enzyme presents reduced CP activities. Applying the torsional network model (TNM), we found that the mutant protein shows more restricted thermal dynamics, although its functional site moves quite similarly to the wild type. Of the four internal clones where KatG(S315T) arose, two present high reproductive rates and secondary mutations at the 5'-UTR region of the gene encoding superoxide dismutase A (sodA), while the other two present significantly lower reproductive rates and lack mutations at genes related with tolerance to oxidative stress. Our results suggest that the resistance mutation KatG(S315T) incurs a fitness cost, which may be alleviated through compensatory mutations at the gene sodA or other genes that respond to oxidative stress, such as the previously known gene ahpC. This suggests that isoniazid treatment could be complemented with drugs that produce oxidative stress in order to hinder the propagation of resistant strains devoid of compensatory mutations.