First-line Antituberculous Drugs Research Articles

Vitamin D as Supplementary Treatment for Newly Diagnosed Pulmonary Tuberculosis patients

Objective: To compare vitamin D with placebo in patients with pulmonary tuberculosis in terms of clinical improvement and sputum conversion. Materials And Methods: This is a prospective randomized, double blind, placebo controlled comparative study conducted for a period of 12 weeks in a tertiary care centre in south India. Total Subjects were 60 new cases of pulmonary tuberculosis who are getting TB treatment initiation, Subjects were randomly allocated into two groups, group A and group B comprising of 30 patients in each group. Group A received vitamin D and group B received placebo. Dosage of vitamin D was 0.25mg/day, given in initial six weeks of antituberculosis drug therapy. Serum level of 25-hydroxyvitamin D was measured at time of diagnosis and at 8 weeks of anti-tuberculous therapy. Measurements of haemoglobin, leukocyte count and serum calcium were done at beginning and repeated at 6th, 8th and 12 weeks. Acid fast bacilli were examined at beginning and on 6th, 8thand 12 weeks. Primary outcome was evaluation of conversion time of sputum smear; secondary outcome was clinical improvement as assessed by TB score. Results: There is no significant difference in mean values of age, haemoglobin level, calcium level,serum Vitamin D, TB score and total lymphocyte count in both groups at start of study.There was no statistical difference in serum calcium level, haemoglobin level and total lymphocyte level at end of study. Mean serum vitamin D level at 8th week of treatment was 27.83±7.09ng/dl in group A and 18.83±2.27 in group B, there was statistically significant difference between two groups. Sixth week sputum conversion in 30 subjects of vitamin D group is 100% and in placebo group, it is 76.7%, which was statistically significant. Conclusion: Supplementary vitamin D when added to first line anti-tuberculous drugs results in shorter conversion time and less severe TB clinical manifestation without any manifestations of hypercalcemia. Therefore, it is recommended to add vitamin D as supplementary treatment to first-line anti-tuberculous drugs in treatment course of active pulmonary TB.

Risk factors for microbiological persistence after 6 months of treatment for Mycobacterium intracellulare and its impact on the drug-resistance profile.

Patients with Mycobacterium intracellulare pulmonary disease are more likely to experience poor treatment outcomes if they have been observed with microbiological persistence after 6 months of treatment. This study aims to identify the risk factors for microbiological persistence and describe the changes in the minimum inhibitory concentration (MIC) during antimycobacterial treatment. This retrospective case-control study enrolled patients diagnosed with M. intracellulare pulmonary disease between April 2017 and September 2021 at Shanghai Pulmonary Hospital. Patients with positive cultures after 6 months of treatment (positive group) were matched by age and sex in a 1:1 ratio to patients with negative conversion (negative group). Totally, 46 pairs of patients were analyzed. Risk factors for microbiological persistence at month 6 were smoking, previous tuberculosis treatment, chronic lung diseases, a positive baseline acid-fast bacilli smear, and adverse drug reactions; the risk was reduced by a regimen containing ethambutol, ≥3 effective drugs, and a higher pre-treatment absolute lymphocyte count. Regarding the drug-resistance profile, the negative group had a higher proportion of susceptibility to clarithromycin (100.0% vs 84.8%, P = 0.012). Most isolates were susceptible or intermediate to amikacin in both groups (93.5% and 84.8%, respectively). Nine patients (16.4%, 9/55) had a change in the drug-resistance profile, including four who changed from clarithromycin susceptible to clarithromycin resistant, and the other three reversed. Two pairs of isolates had a change in resistance to amikacin. In conclusion, risk factors for microbiological persistence were identified, and the change in MIC values during antimycobacterial treatment indicated the need for monitoring to enable timely adjustment of the regimen.IMPORTANCENontuberculous mycobacteria pulmonary disease (NTM-PD) has been recognized as an important public health issue because of its increasing incidence globally, low cure rate, and high recurrence rate. NTM-PD has innate resistance to many first-line anti-tuberculous drugs, which limits the treatment options. Mycobacterium intracellulare is reportedly the most important pathogenic NTM and accounts for the highest proportion of NTM-PD in China. A previous study suggested that poor microbiological response after 6 months of treatment is predictive of treatment failure. The present study investigated the risk factors associated with persistent positive sputum cultures by treatment month 6 in patients with M. intracellulare pulmonary disease and the variation in minimum inhibitory concentration patterns in clinical settings. This information might help to identify patients at higher risk of treatment failure and enable the timely provision of necessary interventions.

A comparison of phenotypic and WGS drug susceptibility testing in Mycobacterium tuberculosis isolates from the Republic of Korea.

WGS has significant potential to help tackle the major public health problem of TB. The Republic of Korea has the third highest rates of TB of all Organisation for Economic Cooperation and Development countries but there has been very limited use of WGS in TB to date. A retrospective comparison of Mycobacterium tuberculosis (MTB) clinical isolates from 2015 to 2017 from two centres in the Republic of Korea using WGS to compare phenotypic drug susceptibility testing (pDST) and WGS drug susceptibility predictions (WGS-DSP). Fifty-seven MTB isolates had DNA extracted and were sequenced using the Illumina HiSeq platform. The WGS analysis was performed using bwa mem, bcftools and IQ-Tree; resistance markers were identified using TB profiler. Phenotypic susceptibilities were carried out at the Supranational TB reference laboratory (Korean Institute of Tuberculosis). For first-line antituberculous drugs concordance for rifampicin, isoniazid, pyrazinamide and ethambutol was 98.25%, 92.98%, 87.72% and 85.96%, respectively. The sensitivity of WGS-DSP compared with pDST for rifampicin, isoniazid, pyrazinamide and ethambutol was 97.30%, 92.11%, 78.95% and 95.65%, respectively. The specificity for these first-line antituberculous drugs was 100%, 94.74%, 92.11% and 79.41%, respectively. The sensitivity and specificity for second-line drugs ranged from 66.67% to 100%, and from 82.98% to 100%, respectively. This study confirms the potential role for WGS in drug susceptibility prediction, which would reduce turnaround times. However, further larger studies are needed to ensure current databases of drug resistance mutations are reflective of the TB present in the Republic of Korea.

Neuromeningeal cryptococcosis in an HIV-negative patient with pulmonary tuberculosis in the Infectious and tropical diseases department of the University teaching hospital Point G of Bamako, Mali

Neuromeningeal cryptococcosis and pulmonary tuberculosis are respectively serious mycotic and bacterial infections occurring in a subject regardless of its HIV serological status. We report here a case of neuromeningeal cryptococcosis associated with pulmonary tuberculosis and malnutrition in an HIV-seronegative patient with a CD4 count of 750/mm3, to highlight some particularities opposed to certain literatures. This is an 18-year-old patient, housewife, from Bamako, admitted in the Infectious and tropical diseases department of the University teaching hospital Point G of Bamako on March 13, 2022 for fever and impaired consciousness. Her symptomatology appears to have gradually set in over a month, preceded by headache resistant to paracetamol, jet vomiting and irregular dry cough, initially treated with ceftriaxone, artesunate and paracetamol for confirmed malaria and suspicion of bacterial meningitis before admission. In whom no known medical-surgical history, no use of topical corticosteroids, no immunosuppressive therapy, no alcohol or tobacco, and no immunosuppressive pathology was found. The diagnoses of neuromeningeal cryptococcosis, pulmonary tuberculosis and undernutrition were retained in view of clinical and microbiological arguments. Diabetes, sickle cell disease, viral hepatitis B and C, kidney failure and cancer, which are immunosuppressive pathologies, were not found. She was successfully treated with first-line oral antituberculous drugs and fluconazole infusion. Three interests are drawn from this clinical case: neuromeningeal cryptococcosis is not only the prerogative of HIV-positive subjects, a high CD4 count does not always mean immunocompetence and fluconazole is an effective therapeutic alternative for neuromeningeal cryptococcosis.

Evaluation Study of xMAP TIER Assay on a Microsphere-Based Platform for Detecting First-Line Anti-Tuberculosis Drug Resistance

Early diagnosis of drug susceptibility for tuberculosis (TB) patients could guide the timely initiation of effective treatment. We evaluated a novel multiplex xMAP TIER (Tuberculosis-Isoniazid-Ethambutol-Rifampicin) assay based on the Luminex xMAP system to detect first-line anti-tuberculous drug resistance. Deoxyribonucleic acid samples from 353 Mycobacterium tuberculosis clinical isolates were amplified by multiplex polymerase chain reaction, followed by hybridization and analysis through the xMAP system. Compared with the broth microdilution method, the sensitivity and specificity of the xMAP TIER assay for detecting resistance was 94.9% (95%CI, 90.0-99.8%) and 98.9% (95%CI, 97.7-100.0%) for rifampicin; 89.1% (95%CI, 83.9-94.3%) and 100.0% (95%CI, 100.0-100.0%) for isoniazid; 82.1% (95% CI, 68.0-96.3%) and 99.7% (95% CI, 99.0-100.0%) for ethambutol. With DNA sequencing as the reference standard, the sensitivity and specificity of xMAP TIER for detecting resistance were 95.0% (95% CI, 90.2-99.8%) and 99.6% (95% CI, 98.9-100.0%) for rifampicin; 96.9% (95% CI, 93.8-99.9%) and 100.0% (95% CI, 100.0-100.0%) for isoniazid; 86.1% (95% CI, 74.8-97.4%) and 100.0% (95% CI, 100.0-100.0%) for ethambutol. The results achieved showed that the xMAP TIER assay had good performance for detecting first-line anti-tuberculosis drug resistance, and it has the potential to diagnose drug-resistant tuberculosis more accurately due to the addition of more optimal design primers and probes on open architecture xMAP system.

Investigation of pncA, rpsA and panD Gene Mutations Associated with Resistance in Pyrazinamide-Resistant Mycobacterium tuberculosis Isolates and Spoligotyping

Pyrazinamide (PZA) is one of the first-line anti-tuberculous drugs used in the treatment of tuberculosis (TB). Considering the ability of PZA to shorten the treatment period from 9-12 months to six months by eliminating persistent bacilli, it appears to be an important cornerstone of TB therapy. While the main mechanism causing the PZA resistance is pncA mutations at a rate of 70-97%, it has been determined that rpsA and panD mutations can also cause resistance. In this study, we aimed to investigate the pncA, rpsA and panD gene mutations, the efficiency of the pyrazinamidase (PZAse) enzyme test in determining PZA resistance, the drug susceptibility and their families in PZA-resistant Mycobacterium tuberculosis isolates. Totally 46 PZA resistant M.tuberculosis isolates were included in the study. The pncA, rpsA and panD mutations caused by PZA resistance were investigated by in-house PCR followed by DNA sequencing method. Drug susceptibility was determined with Bactec MGIT 960 (Becton Dickinson, USA) system, the presence of PZAse was evaluated by colorimetric PZAse enzyme assay and the families were determined by the spoligotyping method. Of the 46 PZA-resistant isolates, 24 (52.2%) were identified as PZA monoresistant, 11 (23.9%) multidrug resistant (MDR)-TB and 11 (23.9%) poly drug resistant (PDR)-TB. Gene mutations associated with resistance were detected in 73.9% (34) of PZA-resistant M.tuberculosis isolates. The pncA, rpsA and panD mutations were found in 71.7% (33), 28.2% (12) and 4.3% (2) of the isolates, respectively. The coexistence of pncA/rpsA and pncA/panD gene mutations were determined in 12 and two isolates, respectively. The pncA gene mutations were observed in 3 (33.3%) of 9 (19.6%) isolates whose enzyme presence was detected by the colorimetric PZAse test. In the pncA gene, eight different point mutations in the form of missense mutation;A226C (27.3%), A152C (24.2%), C169G (21.2%) A422C (9.1%), G145A (6.1%), A29G (6.1%), A424G (3%) and T464G (3%) were detected. In the rpsA gene, A636C (42.9%) silent and G1318A (42.9%) missense mutations and in the panD gene, C66G (50%) nonsense and A145G (50%) missense mutations were the most common mutations detected. As a result of genotyping of PZA resistant isolates, the most common genotypes were found in T1 cluster with 17 (36.9%) isolates; followed by the families of Beijing with 7 (15.2%) isolates, H3 with 6 (13%) isolates, TUR with 5 (10.9%) isolates, and LAM 9 with 4 (8.7%) isolates, respectively. In addition, 2 (4.3%) isolates belonging to the ORPHAN family and one isolate belonging to each of LAM TUR, LAM 2, LAM 7, T2, T5-RUS1 families were identified. Our study is the first to investigate all pncA, rpsA and panD gene mutations that have been found to cause PZA resistance in Turkey. Epidemiological studies on PZA resistance will make important contributions to the determination of resistance mechanism and the development of methods that will provide rapid diagnosis for the detection of resistance.

Tuberculosis in kidney transplant recipients: A retrospective study from a tertiary care center - An observational study

Background: The incidence of tuberculosis (TB) among transplant recipients varies from 5% to 15% across the globe. We conducted a retrospective study to identify the incidence of TB among kidney transplant recipients in our transplant unit. Materials and Methods: We assessed the patients who underwent kidney transplantation in our transplant unit during the study period from January 2014 to June 2018 and included those recipients who had bacteriologically confirmed TB. We excluded the patients who had TB before transplant and those recipients who were initiated on antituberculosis treatment (ATT) empirically. The details collected were: 1. Clinical data, the presenting symptoms, and clinical findings. 2. Diagnostic investigation: Microbiological/histopathological/radiological/bronchoalveolar lavage/fluid (pleural/peritoneal/cerebrospinal fluid) analysis. 3. Antituberculous regimen, dose, and duration of the therapy. 4. Relapse/patient and graft outcome after treatment.Results: The total number of patients who underwent kidney transplantation during the study period was 177. TB occurred in 21 patients after transplantation. The incidence of TB in our transplant unit was 11.86%. In these 21 recipients, 8 had pulmonary TB and the remaining 13 had extrapulmonary/disseminated TB, which included two patients with disseminated TB and one patient with allograft dysfunction with thrombotic microangiopathy which was attributed to TB as it responded to first-line antituberculous drugs. The mortality rate was 23.8%, as five patients expired. After excluding patients who expired, the graft survival at 1 year after ATT completion was 90.5%. Conclusion: For most developing nations, the World Health Organization's “End TB Strategy” remains far from their dream. An ideal investigation to detect TB in its early stage is essential in posttransplant recipients to reduce the morbidity and mortality associated with it.

Molecular Basis of Resistance to First-Line Drugs of Mycobacterium tuberculosis/canettii Strains in Greece.

The aim of this study was to determine the rate and the mutations of genes involved to the first-line antituberculous drugs' resistance of M. tuberculosis/canettii isolated in Central Greece from 2010 to 2019. During the study period, the rate of resistance to isoniazid, rifampicin, ethambutol, and pyrazinamide was 5.4%, 0.4%, 1.1%, and 1.1%, respectively. All phenotypically resistant isolates (14 to isoniazid, 3 to ethambutol, 3 to pyrazinamide, and 1 to rifampicin) and 17 susceptible isolates (control group) were tested for the presence of mutations/alterations/polymorphisms by PCR followed by sequencing analysis. The molecular typing of isolates was based on multispacer sequence typing. Despite the phenotypic resistance, mutations were detected in 13 of 21 isolates (11 isoniazid resistant, 1 rifampicin, and 1 pyrazinamide resistant). Four isoniazid-resistant strains carried the most common mutations S315T and C-15T, whereas the remaining seven isolates carried either less known (E399, A162, W477STOP, S94A, G-48A, C-54T, C-17T, L203, A196, S124, and K367) or novel (D74N, G691S, Ains-85, and D171G); none of the susceptible strains was found to be positive for any novel mutation. The two single rifampicin- and pyrazinamide-resistant strains carried the known mutations S450L (also referred as S531L) and L182W, respectively. The presence of uncommon or novel mutations conferring resistance to isoniazid (INH) creates a diagnostic problem in the routine microbiological laboratory, since commercial methods are focused on the detection of the most common mechanisms of resistance (S315T, C-15T, A-16G, T-8C, and T-8A), therefore, fail to detect such strains. The regional differences in the frequencies of mutations associated with resistance to the first-line drugs provide hints for the development of better molecular-based diagnostic tests.

Primary drug resistance among Mycobacterium tuberculosis isolates from treatment naïve and new pulmonary tuberculosis patients in relation to their socio-economic status

BACKGROUND: Multidrug-resistant Tuberculosis (TB) has become an area of growing concern throughout the World, despite the global efforts in eliminating TB. Detection of primary drug resistance in treatment naïve patients, either due to spontaneous mutation or due to transmission of drug-resistant strains is an important indicator of the presence of drug-resistant strains in the community.OBJECTIVES: The objective is to estimate the prevalence of primary drug resistance in treatment naïve pulmonary TB patients and to identify the socio-economic class of the resistant population.MATERIALS AND METHODS: A total of 272 treatment naïve presumptive TB patients were enrolled in the study from September 2018 to December 2020. The samples were subjected to GeneXpert, for detecting the presence of Mycobacterium TB (MTB) along with Rifampicin (RIF) resistance detection. Phenotypic drug susceptibility testing (DST) was performed on all positive mycobacterial cultures using the 1% proportion method against first-line anti-tuberculous drugs. Socioeconomic status of the patients was also assessed based on updated Kuppuswamy Socioeconomic scale (2018).RESULTS: Of the 272 samples subjected to GeneXpert MTB/RIF assay, MTB was detected in 193 (71%) samples and RIF resistance (rpoB gene) was detected in 25 (9%) samples. Phenotypic DST detected multidrug-resistant (MDR) in 22 (8%) samples. Majority of the MDR patients (55%) were belonging to the upper lower (IV) class of Kuppuswamy socio-economic scale.CONCLUSION: High prevalence of MDR-TB among treatment naïve pulmonary TB patients was noted in patients belonging to Class IV of Kuppuswamy socio-economic scale.

Drug Sensitivity Testing of Mycobacterium tuberculosis Growing in a Hollow Fiber Bioreactor.

Hollow fiber systems (HFSs) have been widely applied to study pharmacokinetic-pharmacodynamic (PK-PD) relationships in antibiotic research and development. The system comprises a bundle of high-density hollow capillary fibers that conduct a flow of medium with or without drug and an extra-capillary space (ECS) inoculated with the pathogen of interest. The semipermeable membrane of the hollow fibers allows for rapid exchange of small molecule drugs and solutes, while the pathogen is restricted to the ECS. The unique properties of the HFS are (1) the ability to simulate any PK profile within the fibers and ECS, including plasma or site-of-disease PK profiles, (2) the ability to simultaneously input several drugs with different half-lives, (3) the ability to manipulate growth conditions such as medium composition, carbon source, and pH, and (4) the ability to sample in both compartments in order to monitor drug concentrations and bacterial growth kinetics over time. The system is particularly suited for Mycobacterium tuberculosis research in a biosafety level 3 (BSL3) environment since pathogenic bacteria are sequestered in an isolated compartment. The HFS was qualified by the European Medicines Agency for antituberculosis drug development in 2015. Here, we describe the standard procedures used to study the growth kinetics of M. tuberculosis in the HFS and the killing effect of first-line antituberculous drugs applied under simulated human PK conditions. This animal-sparing and economical tool can be applied to optimize dosing schedules that minimize emergence of resistance and to prioritize drug regimens that accelerate sterilization.

Genomic Variations in Drug Resistant Mycobacterium tuberculosis Strains Collected from Patients with Different Localization of Infection.

Mycobacterium tuberculosis is a highly studied pathogen due to public health importance. Despite this, problems like early drug resistance, diagnostics and treatment success prediction are still not fully resolved. Here, we analyze the incidence of point mutations widely used for drug resistance detection in laboratory practice and conduct comparative analysis of whole-genome sequence (WGS) for clinical M. tuberculosis strains collected from patients with pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (XPTB) localization. A total of 72 pulmonary and 73 extrapulmonary microbiologically characterized M. tuberculosis isolates were collected from patients from 2007 to 2014 in Russia. Genomic DNA was used for WGS and obtained data allowed identifying major mutations known to be associated with drug resistance to first-line and second-line antituberculous drugs. In some cases previously described mutations were not identified. Using genome-based phylogenetic analysis we identified M. tuberculosis substrains associated with distinctions in the occurrence in PTB vs. XPTB cases. Phylogenetic analyses did reveal M. tuberculosis genetic substrains associated with TB localization. XPTB was associated with Beijing sublineages Central Asia (Beijing CAO), Central Asia Clade A (Beijing A) and 4.8 groups, while PTB localization was associated with group LAM (4.3). Further, the XPTB strain in some cases showed elevated drug resistance patterns relative to PTB isolates. HIV was significantly associated with the development of XPTB in the Beijing B0/W148 group and among unclustered Beijing isolates.

Paediatric Tuberculosis at the Directly Observed Treatment Short-Course Clinic of Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria

Introduction: Tuberculosis (TB) is the leading infectious disease killer worldwide, despite significant progress against the disease in recent years. Most cases of TB in children occur in the TB endemic countries but the actual burden of paediatric TB is unknown. With early diagnosis and treatment using the first-line anti-tuberculous drugs, most people who develop the disease can be cured and onward transmission of infection curtailed.
 Objective: To determine the pattern and outcome of paediatric tuberculosis managed at a tertiary facility in Sokoto, Nigeria.
 Materials and Methods: Records of children managed for TB at the Directly observed treatment short-course (DOTS) clinic over a three-and-a-half-year period were reviewed retrospectively. All children (≤ 15 years) treated for TB over the study period was included. Relevant information was retrieved from the register and analysed accordingly.
 Results: 74 children were treated with 33(44.6%) being males, giving a M: F ratio of 1:1.2. Mean (±SD) age was 85.78 (±55.40) months and 34 (45.9%) belonged to the 0.0-5.0-year age group. Seventy-one (95.9%) were new cases and three (4.1%) were relapse. Pulmonary TB (PTB) was seen in 50 (67.6%), more females had PTB than males, which was not significant (χ2=0.4, p=0.52).
 Acid fast bacilli (AFB) were positive in only 8 (10.8%) while GeneXpert MTB/RIF sensitivity was detected in 7 (9.2%). Majority 36 (48.6%) were lost to follow up, 30 (40.5%) completed treatment, only 4(5.4%) were cured with no recorded mortality. Successful treatment outcome was low (45.9%).
 Conclusion: Treatment outcome using DOTS strategy was poor, far below the WHO benchmark. There is need to improve adherence to DOTs therapy to prevent development of multi drug resistant TB.

Evaluation of the resistance patterns of Mycobacterium tuberculosis complex strains to antituberculous drugs

Aim: To determine the resistance profile of Mycobacterium tuberculosis complex (MTBC) strains to first-line antituberculous drugs. Methods: A total of 138 patients with MTBC growth from 2008-2018 were evaluated retrospectively. The Ehrlich-Ziehl-Neelsen (EZN) staining method was used for direct smear preparations, the BACTEC MGIT 460 TB system the Lowenstein-Jensen medium for culture planting and the BACTEC NAP test for the diagnosis of MTBC. Susceptibility tests were performed using the BACTEC MGIT 460 TB system with the streptomycin, isoniazid, rifampicin and ethambutol (SIRE) kit in accordance with the manufacturer's recommendations. Results: Of the total 138 tuberculosis (TB) cases, 44 (31.9%) were female and 94 (68.1%) were male. MTBC was most frequently isolated from pulmonary specimens (90.6%). Acid-resistant bacilli (ARB) positivity was detected in 88 (63.8%) samples by EZN staining for culture-positive samples. In our study, without considering single or multiple drug resistance (MDR), total resistance rates in MTBC strains were determined for, isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and streptomycin (SM); 10.1%, 4.3%, 2.9%, and 12.3% respectively. While the susceptibility to all drugs was 82.6%, multiple drug–resistant tuberculosis (MDR-TB) was 2.9%. Conclusion: These results are important since they are the first data reported from our province regarding the determination of the resistance profile to anti-TB drugs. Resistance rates in our study were very close to the 2016 data average of the Ministry of Health of Turkey. Determination of TB resistance profiles, as well as proper and regular treatment, will contribute to the control of MDR-TB.

Mielopatía compresiva por Mycobacterium tuberculosis en una niña de origen indígena: un caso clínico de zona endémica amazónica

Introducción. La mielopatía compresiva es ocasionada por diversidad de condiciones. Los abscesos espinales se cuentan como una de sus causas de menor incidencia, con 0.2 a 2 casos por cada 10,000 ingresos hospitalarios, según estadísticas reportadas por el Hospital General de Massachusetts. El Mycobacterium tuberculosis es el segundo patógeno más frecuentemente implicado, con 25% de los casos. Objetivo. Presentar un caso de tuberculosis espinal en edad pediátrica, que es infrecuente pero de relevancia epidemiológica. Presentación del caso. Paciente femenina de siete años de edad, procedente de área endémica amazónica, con sintomatología de compresión de médula espinal. Su historia clínica, nexos epidemiológicos y hallazgos paraclínicos y quirúrgicos llevaron al diagnóstico de tuberculosis espinal. Recibió manejo descompresivo y terapia farmacológica con tetraconjugado, con evolución favorable al momento de su egreso. Conclusiones. La tuberculosis espinal, entidad infecciosa de baja frecuencia, requiere un alto índice de sospecha y un tratamiento oportuno. Las imágenes de resonancia magnética espinal orientan el diagnóstico, confirmándose mediante el aislamiento microbiológico del bacilo. Países como Colombia, con alta endemicidad para el Mycobacterium tuberculosis y con gran proporción de su población en riesgo, deben vigilar de manera constante la tuberculosis y tener presente esta entidad dentro de los diagnósticos diferenciales a descartar. [LeguizamónCastillo DC, Espinosa-García E, Vélez-Pachón CV, CedielEcheverry M. Mielopatía compresiva por Mycobacterium tuberculosis en una niña de origen indígena: un caso clínico de zona endémica amazónica. MedUNAB. 2018;21(1):138146. doi: 10.29375/01237047.2700].

Rapidly Growing Mycobacterial Infections of the Skin and Soft Tissues Caused by M. fortuitum and M. chelonae

Non-tuberculous mycobacteria (NTM) have emerged as pathogens of clinical importance in human health as etiological agents of opportunist infections. Although NTM are known to cause systemic infections in immunocompromised subjects primarily in HIV patients, yet the growing number of immunosuppressed patients with new therapies and even more recently in non-immunocompromised subjects often localized infections of the lungs or skin and soft tissues (SS resistance to first-line anti-tuberculous drugs is common so therapy should be based on in vitro susceptibility testing. More clinical studies due to a lack of standard guidelines for the treatment of RGM infections are needed.

Pharmacokinetic characteristics of first-line anti-tuberculous drugs in gastrectomized patients

Pharmacokinetic characteristics of first-line anti-tuberculous drugs in gastrectomized patients

Development and in-use evaluation of a novel Luminex MicroPlex microsphere-based (TRIOL) assay for simultaneous identification of Mycobacterium tuberculosis and detection of first-line and second-line anti-tuberculous drug resistance in China

AimsRapid and accurate diagnostic assays with simultaneous microbial identification and drug resistance detection are essential for optimising treatment and control of tuberculosis.MethodsWe developed a novel multiplex (TRIOL, Tuberculosis-Rifampicin-Isoniazid-Ofloxacin-Luminex) assay using...

Pyrazinamide Resistance Assays and Two-Month Sputum Culture Status in Patients with Multidrug-Resistant Tuberculosis.

Phenotypic drug susceptibility testing is the current "gold standard" for detecting Mycobacterium tuberculosis susceptibility to antituberculous drugs. Pyrazinamide is one antituberculous drug for which the correlation between in vitro resistance and clinical outcomes remains unclear. Here we performed latent class analysis (LCA) to develop a consensus gold standard definition of pyrazinamide resistance using three paired standard pyrazinamide resistance assays. We then compared this consensus measure to the 2-month culture results for patients with multidrug-resistant tuberculosis (MDR-TB) who were treated for 2 months with first-line antituberculous drugs before their resistance results were known. Among 121 patients with MDR-TB, 60 (49.6%) were resistant to pyrazinamide by the Wayne method (L. G. Wayne, Am Rev Respir Dis 109:147-151, 1974), 71 (58.7%) were resistant by the Bactec MGIT 960 method, and 68 (56.2%) were resistant by pncA sequencing. LCA grouped isolates with positive results by at least two assays into a category which we considered the "consensus gold standard" for pyrazinamide resistance. The sensitivity and specificity for this consensus gold standard were 82.4% and 92.5%, respectively, for the Wayne method; 95.6% and 88.7%, respectively, for the Bactec MGIT 960 method; and 92.6% and 90.6%, respectively, for pncA sequencing. After we adjusted for other factors associated with poor outcomes, including age, sex, alcohol use, and baseline ethambutol resistance, patients whose isolates were resistant by the LCA-derived consensus gold standard were more likely to be culture positive at 2 months with an odds ratio of 1.95 (95% confidence interval, 0.74 to 5.11), but this result was not statistically significant. These findings underscore the need for improved diagnostics for routine use in programmatic settings.

Genotypic characterization of drug resistant Mycobacterium tuberculosis in Quebec, 2002-2012.

BackgroundThe increasing emergence of drug-resistant tuberculosis presents a threat to the effective control of tuberculosis (TB). Rapid detection of drug-resistance is more important than ever to address this scourge. The purpose of this study was to genotypically characterize the first-line antitubercular drug-resistant isolates collected over 11 years in Quebec.ResultsThe main mutations found in our resistant strains collection (n = 225) include: the S315T substitution in katG (50.2 %), the -15 C/T mutation in the inhA promoter (29 %); the S531L substitution in rpoB (43 %); the deletion 8 bp 446 / + R140S in pncA (72.9 %); the M306I (35.7 %) and M306V (21.4 %) substitutions in embB. Ten of the mutations in katG and 4 mutations identified in pncA were previously undescribed.ConclusionScreening of mutations conferring resistance to first-line antituberculous drugs using DNA-sequencing approach seems to be feasible and would drastically shorten the time to determine the resistance profile compared to the proportion method.

Insight into Structure-Function Relationships and Inhibition of the Fatty Acyl-AMP Ligase (FadD32) Orthologs from Mycobacteria

Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is one of the targets of first-line antituberculous drugs. This pathway contains a number of potential targets, including some that have been identified only recently and have yet to be explored. One such target, FadD32, is required for activation of the long meromycolic chain and is essential for mycobacterial growth. We report here an in-depth biochemical, biophysical, and structural characterization of four FadD32 orthologs, including the very homologous enzymes fromMycobacterium tuberculosisandMycobacterium marinum Determination of the structures of two complexes with alkyl adenylate inhibitors has provided direct information, with unprecedented detail, about the active site of the enzyme and the associated hydrophobic tunnel, shedding new light on structure-function relationships and inhibition mechanisms by alkyl adenylates and diarylated coumarins. This work should pave the way for the rational design of inhibitors of FadD32, a highly promising drug target.