Drug-susceptible Tuberculosis Research Articles

The Activities and Secretion of Cytokines Caused by Delamanid on Macrophages Infected by Multidrug-Resistant Mycobacterium tuberculosis Strains.

BackgroundDelamanid (Dlm) is an effective drug against drug-susceptible and drug-resistant Mycobacterium tuberculosis strains, including Multidrug-resistant Mycobacterium tuberculosis (MDR-MTB). There are few reports on the activity and secretion of cytokines caused by Dlm on macrophages infected by MDR-MTB strains. Therefore, this article aims to observe the bactericidal activity and secretion of cytokines of the macrophages infected by MDR-MTB strains after Dlm was administered, so as to provide a basis for further perfecting the mechanism of Dlm.MethodsSamples were respectively collected to count the intracellular colony-forming unit (CFU) of macrophages infected by MDR-MTB or H37Rv strains at 4, 8, 24, and 48 h after Dlm at MIC, 10MIC, and 20MIC were administered. Samples were respectively collected to detect the level of IL-12/23 p40, TNF-α, IL-6, and IL-10 in the culture supernatant of macrophages infected by MDR-MTB or H37Rv strains at 4, 24, and 48 h after Dlm at MIC were administered. The levels of four cytokines in the culture supernatant were measured using the Luminex® 200™ (Luminex, USA) according to the manufacturer’s instructions. Data were analyzed by SPSS 25.0 software. The continuous data in normal distribution were expressed as mean ± standard deviation ( ± s) and analyzed by t or F test. P<0.05 was considered statistically significant.Results(1) After Dlm was applied to macrophages infected by MDR-MTB strains:(A) The intracellular CFU gradually decreased, reached the lowest value at 48 h, and was lower than that of Dlm before administration and infection group (P<0.05). (B) The intracellular CFU was further reduced after increasing Dlm dose to 10MIC and 20MIC, and the latter was lower than that of the former (P<0.05). (C) The intracellular CFU of MDR-MTB group was higher than that of H37Rv group at 4~48 h after administration (P<0.05). (2) After Dlm at MIC dose was applied to macrophages infected by MDR-MTB strains: (A) The level of IL-12/23 p40 at any time didn’t change compared with that of Dlm before administration (P>0.05), while the level of IL-12/23 p40 at 4 h was higher than that of the infection group (P<0.05). The levels of TNF-α at 24 and 48 h were higher than that of Dlm before administration (P<0.05), but were similar to that of the infection group (P>0.05). In addition, the levels of IL-12/23 p40 and TNF-α at any time were similar to that of the H37Rv group after administration (P>0.05). (B) The levels of IL-6 at 24 and 48 h were higher than that of Dlm before administration (P<0.05), but were similar to that of H37Rv group (P>0.05) and were lower than that of infection group (P<0.05). The level of IL-10 at any time didn’t change compared with that of Dlm before administration (P>0.05), but was lower than that of the infection group at 4~48 h and was lower than that of the H37Rv group at 24 h (P<0.05). (C) The level of IL-12/23 p40 and IL-10 didn’t change with the change of intracellular CFU (P<0.05), while the level of TNF-α and IL-6 increased with the intracellular CFU decreasing, and the increase level of TNF-α was lower than that of the infection group (P<0.05).ConclusionsDlm had strong bactericidal activity against intracellular MDR-MTB, which was time-dependent and concentration-dependent. Its bactericidal activity against intracellular MDR-MTB strains was weaker than that against drug-susceptible tuberculosis strains. Dlm might have immunomodulatory effect, inducing low expression of Th2 cytokines IL-6 and IL-10 at different times after administration.

Factors associated with loss to follow-up among TB patients in rural Papua New Guinea.

Papua New Guinea (PNG) is a lower middle-income country that has struggled to contain TB. The loss of patients to follow-up is a major contributing factor towards the high disease burden. To describe persons with drug-susceptible TB (DS-TB) registered for treatment at the Gaubin Rural Hospital (GRH) on Karkar Island, Madang Province, PNG, and to investigate factors associated with patient loss to follow-up (LTFU). A retrospective cohort study was conducted using data from GRH DS-TB registers. Factors associated with LTFU were investigated using univariable and multivariable logistic regression. A total of 722 patients were registered for DS-TB treatment and eligible for inclusion between 1 January 2014 and 30 June 2018, of whom 97 (13.4%) were lost to follow-up. Male sex was associated with an increased odds of LTFU (adjusted OR [aOR] 1.9, 95% CI 1.2-3.0; P = 0.005), as was travel time to GRH >3 h (aOR 3.7, 95%, CI 2.2-6.3; P < 0.001). A high LTFU rate has been identified in patients with TB in PNG. This study found male sex and increased travel time from treatment location to be associated with unsuccessful treatment adherence, highlighting the need for further interventions to improve adherence.

Whole Genome Sequencing of Drug Resistant and Drug Susceptible Mycobacterium tuberculosis Isolates From Tigray Region, Ethiopia.

Background: Tuberculosis, mainly caused by Mycobacterium tuberculosis (Mtb), is an ancient human disease that gravely affects millions of people annually. We wanted to explore the genetic diversity and lineage-specific association of Mtb with drug resistance among pulmonary tuberculosis patients.Methods: Sputum samples were collected from pulmonary tuberculosis patients at six different healthcare institutions in Tigray, Ethiopia, between July 2018 and August 2019. DNA was extracted from 74 Mtb complex isolates for whole-genome sequencing (WGS). All genomes were typed and screened for mutations with known associations with antimicrobial resistance using in silico methods, and results were cross-verified with wet lab methods.Results: Lineage (L) 4 (55.8%) was predominant, followed by L3 (41.2%); L1 (1.5%) and L2 (1.5%) occurred rarely. The most frequently detected sublineage was CAS (38.2%), followed by Ural (29.4%), and Haarlem (11.8%). The recent transmission index (RTI) was relatively low. L4 and Ural strains were more resistant than the other strains to any anti-TB drug (P < 0.05). The most frequent mutations to RIF, INH, EMB, SM, PZA, ETH, FLQs, and 2nd-line injectable drugs occurred at rpoB S450L, katG S315T, embB M306I/V, rpsL K43R, pncA V139A, ethA M1R, gyrA D94G, and rrs A1401G, respectively. Disputed rpoB mutations were also shown in four (16%) of RIF-resistant isolates.Conclusion: Our WGS analysis revealed the presence of diverse Mtb genotypes. The presence of a significant proportion of disputed rpoB mutations highlighted the need to establish a WGS facility at the regional level to monitor drug-resistant mutations. This will help control the transmission of DR-TB and ultimately contribute to the attainment of 100% DST coverage for TB patients as per the End TB strategy.

Pharmacodynamics and Bactericidal Activity of Bedaquiline in Pulmonary Tuberculosis.

Bedaquiline is a diarylquinoline antimycobacterial drug and a key component of several regimens in clinical development for the treatment of tuberculosis (TB) but with ongoing phase 3 trials that include assessment of simplified dosing. A pharmacokinetic-pharmacodynamic model of bedaquiline Mycobacterium tuberculosis-killing kinetics in adults with pulmonary TB was developed to inform dose selection of bedaquiline-containing regimens. The model parameters were estimated with data from the 14-day early bactericidal activity (EBA) study TMC207-CL001 conducted in Cape Town, South Africa. The study included 60 adult males and females with drug-susceptible pulmonary TB, who were administered bedaquiline with loading doses on the first 2 days followed by once-daily 100 mg, 200 mg, 300 mg, or 400 mg. The modeling results included expected values (means ± standard deviations [SDs]) for a maximum drug kill rate constant equal to 0.23 ± 0.03 log10 CFU/mL sputum/day, a half-maximum effective plasma concentration equal to 1.6 ± 0.3 mg/L, and an average time to onset of activity equal to 40 ± 7 h. Model simulations showed that once-daily 200 mg, 300 mg, and 400 mg (without loading doses) attained 40%, 50%, and 60%, respectively, of an expected maximum 14-day EBA equal to 0.18 log10 CFU/mL/day, or 10 h/day assessed by liquid culture time to positivity (TTP). Additional simulations illustrated efficacy outcomes during 8 weeks of treatment with the recommended and alternative dosages. The results demonstrate a general mathematical and statistical approach to the analysis of EBA studies with broad application to TB regimen development.

1400. Pretomanid in the Treatment of Patients with Tuberculosis in the United States: the Bedaquiline, Pretomanid and Linezolid (BPaL) Accelerated Monitoring (BAM) Project

BackgroundIn August 2019 the U.S. FDA approved pretomanid as part of a 6-month all-oral BPaL (bedaquiline, pretomanid, and linezolid) regimen for treating pulmonary extensively drug-resistant (XDR) or treatment-intolerant or nonresponsive multidrug-resistant (MDR) tuberculosis (TB). In the study supporting approval, 89% of patients had a favorable outcome, and all reported ≥ 1 adverse event. We describe the reported use of BPaL in the United States.MethodsUsing the 2020 CDC Report of a Verified Case of Tuberculosis (RVCT) MDR TB supplemental form, TB programs and providers submitted data for patients who began taking BPaL between Aug 1, 2019 and May 1, 2020, for retrospective descriptive analysis.ResultsPrograms and providers reported 17 TB patients aged a mean of 41 years (range 23–76) who received BPaL: 11 (65%) were male; 15 (88%) were non-U.S. born; 15 (88%) had pulmonary TB disease only; two (12%) had both pulmonary and extrapulmonary disease. Of all patients, 16 had Mycobacterium tuberculosis isolated from sputum and 7 (44%) had cavitary disease. The preliminary drug susceptibilities were 8 MDR patterns, 8 pre-XDR, and 1 unreported. Three patients received BPaL as their only treatment; six first received treatment for drug-susceptible TB, and eight received other regimens for MDR TB before BPaL. Eleven (65%) patients had ≥ 1 side effect reported during any TB treatment, including peripheral neuropathy (n=5), depression (n=4), vestibular dysfunction (n=3), and vision changes (n=3). Timing related to specific TB drug use was not reported. Sixteen (94%) patients received less than the approved initial dose of 1200 mg linezolid daily, and 15 (88%) patients underwent monitoring of linezolid exposure. All 16 patients with M. tuberculosis in initial sputa converted to negative culture results within 6 months of starting treatment. At 12 months after BPaL initiation, all patients had completed treatment, without TB recurrences or deaths reported.ConclusionIn the early period after FDA approval, most U.S. patients received BPaL off-label with an initial linezolid dose lower than the approved 1200mg yet still achieved good outcomes. Most reported patients underwent some monitoring of linezolid exposure. Monitoring of BPaL use is important and should continue.Disclosures All Authors: No reported disclosures

High rate of successful treatment outcomes among childhood rifampicin/multidrug-resistant tuberculosis in Pakistan: a multicentre retrospective observational analysis

BackgroundThere was a complete lack of information about the treatment outcomes of rifampicin/multidrug resistant (RR/MDR) childhood TB patients (age ≤ 14 years) from Pakistan, an MDR-TB 5th high burden country. Therefore, this study evaluated the socio-demographic characteristics, drug resistance pattern, treatment outcomes and factors associated with unsuccessful outcomes among childhood RR/MDR-TB patients in Pakistan.MethodsThis was a multicentre retrospective record review of all microbiologically confirmed childhood RR/MDR-TB patients (age ≤ 14 years) enrolled for treatment at seven units of programmatic management of drug-resistant TB (PMDT) in Pakistan. The baseline and follow-up information of enrolled participants from treatment initiation until the end of treatment were retrieved from electronic nominal recording and reporting system. World Health Organization (WHO) defined criterion was used for deciding treatment outcomes. The outcomes of “cured” and “treatment completed” were collectively grouped as successful, whereas “death”, “treatment failure” and “lost to follow-up” were grouped together as unsuccessful outcomes. Multivariable binary logistic regression analysis was used to find factors associated with unsuccessful outcomes. A p-value < 0.05 reflected statistically significant findings.ResultsA total of 213 children RR/MDR-TB (84 RR and 129 MDR-TB) were included in the study. Majority of them were females (74%), belonged to the age group 10–14 years (82.2%) and suffered from pulmonary TB (85.9%). A notable proportion (37.1%) of patients had no history of previous TB treatment. Patients were resistant to a median of two drugs (interquartile range: 1–4) and 23% were resistant to any second line anti-TB drug. A total of 174 (81.7%) patients achieved successful treatment outcomes with 144 (67.6%) patients being cured and 30 (14.1%) declared treatment completed. Among the 39 (18.3%) patients with unsuccessful outcomes, 35 (16.4%) died and 4 (1.9%) experienced treatment failure. In multivariable analysis, the use of ethambutol had statistically significant negative association with unsuccessful outcomes (odds ratio = 0.36, p-value = 0.02).ConclusionsIn this study, the WHO target of successful treatment outcomes (≥ 75%) among childhood RR/MDR-TB patients was achieved. The notable proportion of patients with no history of previous TB treatment (37.1%) and the disproportionately high number of female patients (74%) respectively stress for infection control measures and provision of early and high quality care for female drug susceptible TB patients.

Adverse effects and duration of treatment of TB in Canterbury, New Zealand.

BACKGROUND Treatment of TB is often extended beyond the recommended duration. The aim of this study was to assess prevalence of extended treatment and to identify associated risk factors. We also aimed to determine the frequency and type of adverse drug reactions (ADR) experienced by this study population.METHODS We performed a retrospective cohort study of all patients treated for active TB at Christchurch Hospital, Christchurch, New Zealand, between 1 March 2012 and 31 December 2018. Data for 192 patients were collected on patient demographics, disease characteristics and treatment characteristics, including planned and actual duration of treatment and ADRs.RESULTS Of 192 patients, 35 (18.2%) had treatment extended, and 85 (46.5%) of 183 with fully drug-susceptible TB received ≥9 months treatment. The most common reasons for extension were persistent or extensive disease and ADR. Extended treatment duration was not associated with any patient or disease characteristics. We found 35 (18.2%) patients experienced at least one ADR. The most common ADRs were hepatitis, rash and peripheral neuropathy.CONCLUSION TB treatment extension beyond WHO guidelines is common. Further research is needed to guide management of those with slow response to treatment. Methods for early detection of ADR, systems to improve adherence and therapeutic drug monitoring are potentially useful strategies.

Impact of socio-economic factors on Tuberculosis treatment outcomes in north-eastern Uganda: a mixed methods study

BackgroundTuberculosis (TB) is a major public health problem and at 48%, Karamoja in North-Eastern Uganda has the lowest treatment success rate nationally. Addressing the social determinants of TB is crucial to ending TB. This study sought to understand the extent and ways in which socio-economic factors affect TB treatment outcomes in Karamoja.MethodsWe conducted a convergent parallel mixed methods study in 10 TB Diagnostic and Treatment Units. The study enrolled former TB patients diagnosed with drug-susceptible TB between April 2018 and March 2019. Unit TB and laboratory registers were reviewed to identify pre-treatment losses to follow-up. Four focus group discussions with former TB patients and 18 key informant interviews with healthcare workers were conducted. Principle component analysis was used to generate wealth quintiles that were compared to treatment outcomes using the proportion test. The association between sociodemographic characteristics and TB treatment outcomes was evaluated using the chi-square test and multiple logistic regression.ResultsA total of 313 participants were randomly selected from 1184 former TB patients recorded in the unit TB registers. Of these, 264 were contacted in the community and consented to join the study: 57% were male and 156 (59.1%) participants had unsuccessful treatment outcomes. The wealthiest quintile had a 58% reduction in the risk of having an unsuccessful treatment outcome (adj OR = 0.42, 95% CI 0.18–0.99, p = 0.047). People who were employed in the informal sector (adj OR = 4.71, 95% CI 1.18–18.89, p = 0.029) and children under the age of 15 years who were not in school or employed (adj OR = 2.71, 95% CI 1.11–6.62, p = 0.029) had significantly higher odds of unsuccessful treatment outcome. Analysis of the pre-treatment loss to follow-up showed that 17.2% of patients with pulmonary bacteriologically confirmed TB did not initiate treatment with a higher proportion among females (21.7%) than males (13.5%). Inadequate food, belonging to migratory communities, stigma, lack of social protection, drug stock-outs and transport challenges affected TB treatment outcomes.ConclusionsThis study confirmed that low socio-economic status is associated with poor TB treatment outcomes emphasizing the need for multi- and cross-sectoral approaches and socio-economic enablers to optimise TB care.

Clinical Relevance of Rifampicin-Moxifloxacin Interaction in Isoniazid-Resistant/Intolerant Tuberculosis Patients.

Moxifloxacin is an attractive drug for the treatment of isoniazid-resistant rifampicin-susceptible tuberculosis (TB) or drug-susceptible TB complicated by isoniazid intolerance. However, co-administration with rifampicin decreases moxifloxacin exposure. It remains unclear whether this drug-drug interaction has clinical implications. This retrospective study in a Dutch TB center investigated how rifampicin affected moxifloxacin exposure in patients with isoniazid-resistant or -intolerant TB. Moxifloxacin exposures were measured between 2015 and 2020 in 31 patients with isoniazid-resistant or -intolerant TB receiving rifampicin, and 20 TB patients receiving moxifloxacin without rifampicin. Moxifloxacin exposure, i.e., area under the concentration-time curve (AUC0-24h), and attainment of AUC0-24h/MIC > 100 were investigated for 400 mg moxifloxacin and 600 mg rifampicin, and increased doses of moxifloxacin (600 mg) or rifampicin (900 mg). Moxifloxacin AUC0-24h and peak concentration with a 400 mg dose were decreased when rifampicin was co-administered compared to moxifloxacin alone (ratio of geometric means 0.61 (90% CI (0.53, 0.70) and 0.81 (90% CI (0.70, 0.94), respectively). Among patients receiving rifampicin, 65% attained an AUC0-24h/MIC > 100 for moxifloxacin compared to 78% of patients receiving moxifloxacin alone; this difference was not significant. Seven out of eight patients receiving an increased dose of 600 mg moxifloxacin reached the target AUC0-24h/MIC > 100. This study showed a clinically significant 39% decrease in moxifloxacin exposure when rifampicin was co-administered. Moxifloxacin dose adjustment may compensate for this drug-drug interaction. Further exploring the impact of higher doses of these drugs in patients with isoniazid resistance or intolerance is paramount.

Comparative Performance of Genomic Methods for the Detection of Pyrazinamide Resistance and Heteroresistance in Mycobacterium tuberculosis.

ABSTRACTPyrazinamide is an important component of both drug-susceptible and drug-resistant tuberculosis treatment regimens. Although approximately 50% of rifampin-resistant isolates are also resistant to pyrazinamide, pyrazinamide susceptibility testing is not routinely performed due to the challenging nature of the assay. We investigated the diagnostic accuracy of genotypic and phenotypic methods and explored the occurrence of pyrazinamide heteroresistance. We assessed pyrazinamide susceptibility among 358 individuals enrolled in the South African EXIT-RIF cohort using Sanger and targeted deep sequencing (TDS) of the pncA gene, whole-genome sequencing (WGS), and phenotypic drug susceptibility testing. We calculated the diagnostic accuracy of the different methods and investigated the prevalence and clinical impact of pncA heteroresistance. True pyrazinamide susceptibility status was assigned to each isolate using the Köser classification and expert rules. We observed 100% agreement across genotypic methods for detection of pncA fixed mutations; only TDS confidently identified three isolates (0.8%) with minor variants. For the 355 (99.2%) isolates that could be assigned true pyrazinamide status with confidence, phenotypic DST had a sensitivity of 96.5% (95% confidence interval [CI], 93.8 to 99.3%) and specificity of 100% (95% CI, 100 to 100%), both Sanger sequencing and WGS had a sensitivity of 97.1% (95% CI, 94.6 to 99.6%) and specificity of 97.8% (95% CI, 95.7 to 99.9%), and TDS had sensitivity of 98.8% (95% CI, 97.2 to 100%) and specificity of 97.8% (95% CI, 95.7 to 99.9%). We demonstrate high sensitivity and specificity for pyrazinamide susceptibility testing among all assessed genotypic methods. The prevalence of pyrazinamide heteroresistance in Mycobacterium tuberculosis isolates was lower than that identified for other first-line drugs.

&lt;i&gt;NAT2&lt;/i&gt; gene polymorphism and development of multiple drug resistant tuberculosis in patients with HIV infection

The objective: to run the comparative study of frequencies of variants of polymorphic loci of NAT2 gene in the development of multiple drug resistant tuberculosis (MDR TB) and drug sensitive tuberculosis (DS TB) in patients with HIV infection. Subjects and Methods. 70 patients with TB/HIV co-infection at the age from 24 to 58 years old were examined when admitted to hospital. 54 (77.1%) patients were new cases, the remaining 16 cases underwent repeated treatment. MDR TB was diagnosed in 47 patients: 33 patients had primary MDR, and 14 patients suffered from acquired MDR. Drug susceptible tuberculosis was diagnosed in 23 patients. Allele-specific PCR was used for genotyping of patients by rs1208, rs1799930, and rs1799929 polymorphic loci of N-acetyltransferase-2 ( NAT2 ) gene. Results. A high probability of carriage of wild genotype of NAT2 Arg197Arg(G590G) and allele NAT2 Arg197(590G) was revealed in MDR TB( n = 70, OR = 3.63, p = 0.02 and OR = 2.24, p = 0.05, respectively) and it was found low in DS TB ( n = 70, OR = 0.28, p = 0.02 and OR = 0.45, p = 0.05, respectively). Among patients with acquired MDR TB ( n = 14), carriers of the wild genotype of NAT2 Arg197Arg(G590G) prevailed ( n = 11; 79%), of them 10 were chronic cases and 1 had a relapse. Among patients with DS TB ( n = 23), the carriage of the wild genotype of NAT2 Arg197Arg G590G was found in 35% of patients ( n = 8), of them 7 were new cases and 1 patient suffered from chronic tuberculosis. Carriage of a combination of three studied wild genotypes of NAT2 Lys268Lys(A803A) × NAT2 Arg197Arg(G590G) × NAT2 Leu161Leu(C481C) was more often recorded in secondary MDR TB. In secondary MDR TB, the risk of carriage of wild genotypes of NAT2 gene versus primary MDR TB turned out to be high among all cases of diagnosed MDR TB ( n = 43, OR = 6.67 [1.28-34.86], p = 0.0277 ) and in the entire sample ( n = 65, OR = 11.91 [2.32-61.11], p = 0.0039). Conclusion. The results of genotyping in patients with TB/HIV co-infection and secondary MDR TB are associated with the carriage of acombination of wild genotypes of gene NAT2 Lys268Lys(A803A) × NAT2 Arg197Arg(G590G) × NAT2 Leu161Leu(C481C) .

Factors Associated with Unsuccessful Outcomes of Tuberculosis Treatment in 125 Municipalities in Colombia 2014 to 2016.

Our aim was to identify the risk factors associated with unsuccessful outcomes of tuberculosis (TB) treatment in patients diagnosed between 2014 and 2016 in the 125 municipalities of Antioquia, Colombia. We studied a retrospective cohort of patients with TB diagnosed between 2014 and 2016, from national routine surveillance systems, in 125 municipalities of Antioquia. Factors associated with unsuccessful tuberculosis treatment outcomes (treatment failed, lost to follow up, or death) were identified utilizing a Poisson regression with robust variance. Over 3 years, of the 6,739 drug-susceptible tuberculosis patients, 73.4% had successful treatment and 26.6% unsuccessful outcomes (17% lost to follow up, 8.9% deaths, and 0.7% treatment failures). Patients with subsidized health insurance (Relative risk [RR]: 2.4; 95% CI: 2.1-2.8) and without health insurance (RR: 2.5; 95% CI: 2.1-3.0) had a higher risk for unsuccessful tuberculosis treatment compared to those with contributive health insurance. Other risk factors included age over 15 years, male sex, homelessness, people living with HIV, previous treatment, and primary diagnosis during hospitalization. Protective factors were living in a rural area and extrapulmonary disease. It is important to generate strategies that improves tuberculosis diagnosis in primary healthcare institutions. In addition, it is imperative to initiate new research about the barriers and obstacles related to patients, healthcare workers and services, and the health system, including the analysis of urban violence, to understand why the goal of TB treatment success has not been reached.

Infliximab to Treat Severe Paradoxical Reaction in HIV-Negative Tuberculous Meningoencephalitis.

Tuberculous meningoencephalitis was diagnosed in a 33-year-old HIV-negative patient. CSF culture was positive for drug-susceptible Mycobacterium tuberculosis and antituberculous therapy associated with steroids was started. After 3 months, brain MRI showed a worsening of the basal meningeal enhancement and the patient complained of new headaches. CSF analysis demonstrated pleocytosis (100 cells/mm3), with an increased protein count (2,580 mg/dL); CSF culture and viral panel were negative. The worsening was considered due to immune reconstitution inflammatory syndrome and infliximab was started1,2, leading to dramatic clinical and imaging improvement (Figure).

Clinical Factors Associated with Cavitary Tuberculosis and Its Treatment Outcomes.

Cavitary pulmonary tuberculosis (TB) is associated with poor outcomes, treatment recurrence, higher transmission rates, and the development of drug resistance. However, reports on its clinical characteristics, associated factors, and treatment outcomes are lacking. Hence, this study sought to evaluate the clinical factors associated with cavitary pulmonary TB and its treatment outcomes. We retrospectively evaluated 410 patients with drug-susceptible pulmonary TB in a university hospital in Korea between 2014 and 2019. To evaluate the factors associated with cavitary TB, multivariable logistic regression was performed with adjustments for potential confounders. We also compared the treatment outcomes between patients with cavitary TB and those without cavitary TB. Of the 410 patients, 244 (59.5%) had non-cavitary TB and 166 (40.5%) had cavitary TB. Multivariable logistic analysis with forward selection method showed that body mass index (BMI) (adjusted OR = 0.88, 95% CI: 0.81–0.97), previous history of TB (adjusted OR = 3.45, 95% CI: 1.24–9.59), ex- or current smoker (adjusted OR = 1.77, 95% CI: 1.01–3.13), diabetes mellitus (adjusted OR = 2.72, 95% CI: 1.36–5.44), and positive results on the initial sputum acid-fast bacilli (AFB) smear (adjusted OR = 2.24, 95% CI: 1.26–3.98) were significantly associated with cavitary TB. Although treatment duration was significantly longer in patients with cavitary TB than in those with non-cavitary TB (248 (102–370 days) vs. 202 (98–336 days), p < 0.001), the recurrence rate after successful treatment was significantly higher in the patients with cavitary TB than in those with non-cavitary TB (0.4% vs. 3.0% p = 0.042). In conclusion, ex- or current smoker, lower BMI, previous history of TB, diabetes mellitus, and positivity of the initial AFB smear were associated with cavitary TB. The patients with cavitary TB had more AFB culture-positive results at 2 months, longer treatment duration, and higher recurrence rates than those with non-cavitary TB.

Optimizing Dosing and Fixed-Dose Combinations of Rifampicin, Isoniazid, and Pyrazinamide in Pediatric Patients With Tuberculosis: A Prospective Population Pharmacokinetic Study.

In 2010, the World Health Organization (WHO) revised dosing guidelines for treatment of childhood tuberculosis. Our aim was to investigate first-line antituberculosis drug exposures under these guidelines, explore dose optimization using the current dispersible fixed-dose combination (FDC) tablet of rifampicin/isoniazid/pyrazinamide; 75/50/150mg, and suggest a new FDC with revised weight bands. Children with drug-susceptible tuberculosis in Malawi and South Africa underwent pharmacokinetic sampling while receiving first-line tuberculosis drugs as single formulations according the 2010 WHO recommended doses. Nonlinear mixed-effects modeling and simulation was used to design the optimal FDC and weight-band dosing strategy for achieving the pharmacokinetic targets based on literature-derived adult AUC0-24h for rifampicin (38.7-72.9), isoniazid (11.6-26.3), and pyrazinamide (233-429 mg ∙ h/L). In total, 180 children (42% female; 13.9% living with human immunodeficiency virus [HIV]; median [range] age 1.9 [0.22-12] years; weight 10.7 [3.20-28.8] kg) were administered 1, 2, 3, or 4 FDC tablets (rifampicin/isoniazid/pyrazinamide 75/50/150mg) daily for 4-8, 8-12, 12-16, and 16-25kg weight bands, respectively. Rifampicin exposure (for weight and age) was up to 50% lower than in adults. Increasing the tablet number resulted in adequate rifampicin but relatively high isoniazid and pyrazinamide exposures. Administering 1, 2, 3, or 4 optimized FDC tablets (rifampicin/isoniazid/pyrazinamide 120/35/130mg) to children < 6, 6-13, 13-20. and 20-25kg, and 0.5 tablet in < 3-month-olds with immature metabolism, improved exposures to all 3 drugs. Current pediatric FDC doses resulted in low rifampicin exposures. Optimal dosing of all drugs cannot be achieved with the current FDCs. We propose a new FDC formulation and revised weight bands.

Measuring Tuberculosis Medication Adherence: A Comparison of Multiple Approaches in Relation to Urine Isoniazid Metabolite Testing Within a Cohort Study in India.

BackgroundNonadherence to tuberculosis medications is associated with poor outcomes. However, measuring adherence in practice is challenging. In this study, we evaluated the accuracy of multiple tuberculosis adherence measures.MethodsWe enrolled adult Indians with drug-susceptible tuberculosis who were monitored using 99DOTS, a cellphone-based technology. During an unannounced home visit with each participant, we assessed adherence using a pill estimate, 4-day dose recall, a last missed dose question, and urine isoniazid metabolite testing. We estimated the area under the receiver operating characteristic curve (AUC) for each alternate measure in comparison to urine testing. 99DOTS data were analyzed using patient-reported doses alone and patient- and provider-reported doses, the latter reflecting how 99DOTS is implemented in practice. We assessed each measure’s operating characteristics, with particular interest in specificity—that is, the percentage of participants detected as being nonadherent by each alternate measure, among those who were nonadherent by urine testing.ResultsCompared with urine testing, alternate measures had the following characteristics: 99DOTS patient-reported doses alone (area under the curve [AUC], 0.65; specificity, 70%; 95% CI, 58%–81%), 99DOTS patient- and provider-reported doses (AUC, 0.61; specificity, 33%; 95% CI, 22%–45%), pill estimate (AUC, 0.55; specificity, 21%; 95% CI, 12%–32%), 4-day recall (AUC, 0.60; specificity, 23%; 95% CI, 14%–34%), and last missed dose question (AUC, 0.65; specificity, 52%; 95% CI, 40%–63%).ConclusionsAlternate measures missed detecting at least 30% of people who were nonadherent by urine testing. The last missed dose question performed similarly to 99DOTS using patient-reported doses alone. Tuberculosis programs should evaluate the feasibility of integrating more accurate, objective measures, such as urine testing, into routine care.

High rates of culture conversion and low loss to follow-up in MDR-TB patients managed at Regional Referral Hospitals in Uganda

BackgroundMulti-drug resistant—tuberculosis (MDR-TB) is an emerging public health concern in Uganda. Prior to 2013, MDR-TB treatment in Uganda was only provided at the national referral hospital and two private-not-for profit clinics. From 2013, it was scaled up to seven regional referral hospitals (RRH). The aim of this study was to measure interim (6 months) treatment outcomes among the first cohort of patients started on MDR-TB treatment at the RRH in Uganda.MethodsThis was a cross-sectional study in which a descriptive analysis of data collected retrospectively on a cohort of 69 patients started on MDR-TB treatment at six of the seven RRH between 1st April 2013 and 30th June 2014 and had been on treatment for at least 9 months was conducted.ResultsOf the 69 patients, 21 (30.4%) were female, 39 (56.5%) HIV-negative, 30 (43.5%) resistant to both isoniazid and rifampicin and 57 (82.6%) category 1 or 2 drug susceptible TB treatment failures. Median age at start of treatment was 35 years (Interquartile range (IQR): 27–45), median time-to-treatment initiation was 27.5 (IQR: 6–89) days and of the 30 HIV-positive patients, 27 (90.0%) were on anti-retroviral treatment with a median CD4 count of 206 cells/microliter of blood (IQR: 113–364.5). Within 6 months of treatment, 59 (85.5%) patients culture converted, of which 45 (65.2%) converted by the second month and the other 14 (20.3%) by the sixth month; one (1.5%) did not culture convert; three (4.4%) died; and six (8.8%) were lost-to-follow up. Fifty (76.8%) patients experienced at least one drug adverse event, while 40 (67.8%) gained weight. Mean weight gained was 4.7 (standard deviation: 3.2) kilograms.ConclusionsDespite MDR-TB treatment initiation delays, most patients had favourable interim treatment outcomes with majority culture converting early and very few getting lost to follow-up. These encouraging interim outcomes indicate the potential for success of a scale-up of MDR-TB treatment to RRH.

Predicting the impact of control strategies on the tuberculosis burden in South and North Korea using a mathematical model

BackgroundAmong high-income countries, South Korea has a considerable tuberculosis (TB) burden; North Korea has one of the highest TB burdens in the world. Predicting the impact of control strategies on...

Recent Advances in Drug Susceptible Pulmonary Tuberculosis Diagnosis and Treatment

The most important thing for the management of drug susceptible pulmonary tuberculosis is to diagnose active pulmonary tuberculosis as soon as possible and prevent the occurrence of new patients through appropriate treatment. Therefore, it should be a priority to quickly detect tuberculosis mycobacterium and quickly exclude drug-resistant tuberculosis before treatment begins. To this end, recent guidelines recommend the general use of &lt;i&gt;Mycobacterium tuberculosis&lt;/i&gt; (MTB) polymerase chain reaction (PCR) tests, Xpert MTB/RIF tests, and rapid sensitivity tests through line probe assay (LPA). In addition, if the results of the test are positive, it is important to establish an in-hospital reporting system so that rapid reporting can be made. The treatment principle for drug susceptible pulmonary tuberculosis is 2 months of initial intensive phase (isoniazid, rifampin, ethambutol, pyrazinamide) followed by 4 months of maintenance phase (isoniazid, rifampin). Despite global efforts to shorten the duration of the treatment, the treatment of drug susceptible pulmonary tuberculosis has not changed for more than 35 years, and problems such as increased side effects and reduced drug adherence are serious obstacles to tuberculosis management. Therefore, efforts have been steadily made to shorten the treatment period through the combination of new drugs worldwide, and after many failures, they are finally paying off. A recently published Study 31/A5349 study found that 4 months short-term regimen using rifapentine (RPT) and moxifloxacin (MFX) demonstrated non-inferiority in existing standard regimen, as the result, a revision of World Health Organization guidelines is scheduled that 4 months short-term regimen using RPT and MFX may be an alternative. However, it is unlikely that RPT/MFX 4 months short-term regimen will be applied immediately in Korea because the use of RPT is currently limited in Korea due to the high frequency of side effects.

Analysis of Factors Influencing Multidrug-Resistant Tuberculosis and Validation of Whole-Genome Sequencing in Children with Drug-Resistant Tuberculosis.

ObjectivePediatric tuberculosis (TB) is one of the top ten causes of death in children. Our study was to analyze influencing factors of multidrug-resistant tuberculosis (MDR-TB) and validation of whole-genome sequencing (WGS) used in children with drug-resistant TB (DR-TB).MethodsAll Mycobacterium tuberculosis (Mtb) strains were isolated from patients aged below 18 years old of Children’s Hospital of Chongqing Medical University, China. A total of 208 Mtb isolates were tested for eight anti-TB drugs with phenotypic drug susceptibility test (DST) and for genetic prediction of the susceptible profile with WGS. The patients corresponding to each strain were grouped according to drug resistance and genotype. Influencing factors of MDR-TB and DR-TB were analyzed.ResultsAccording to the phenotypic DST and WGS, 82.2% of Mtb strains were susceptible to all eight drugs, and 6.3% were MDR-TB. Using the phenotypic DSTs as the gold standard, the kappa value of WGS to predict isoniazid, rifampin, ethambutol, rifapentine, prothionamide, levofloxacin, moxifloxacin and amikacin was 0.84, 0.89, 0.59, 0.86, 0.89, 0.82, 0.88 and 1.00, respectively. There was significant difference in the distribution of severe TB, diagnosis, treatment and outcome between MDR and drug-susceptible group (P<0.05). The distribution of severe TB and treatment between DR and drug-susceptible group was statistically different (P<0.05). The results of binary logistic regression showed that Calmette–Guérin bacillus (BCG) vaccine is the protective factor for MDR-TB (OR=0.19), and MDR-TB is the risk factor for PTB and EPTB (OR=17.98).ConclusionThe BCG vaccine is a protective factor for MDR-TB, and MDR-TB might not be confined to pulmonary infection, spreading to extrapulmonary organs in children. MDR-TB had more severe cases and a lower recovery rate than drug-susceptible TB. WGS could provide an accurate prediction of drug susceptibility test results for anti-TB drugs, which are needed for the diagnosis and precise treatment of TB in children.