Introduction and scaling up of new drugs for drug-resistant TB: experiences from the Americas.

The number of multidrug-resistant tuberculosis (MDR-TB) cases reported in the Americas has increased by 21.2%, from 3737 in 2016 to 4791 in 2018. The WHO has been recommending changes on the treatment of DR-TB, moving from long-duration treatment with injectables to a short oral regimen with new drugs such as bedaquiline (BDQ) and delamanid (DLM), in selected cases and only under programmatic conditions. Injectables are no longer recommended by the WHO due to lower efficacy and the increasing seriousness of adverse events. The introduction of new oral drugs for DR-TB received a boost with a global donation of BDQ to some eligible countries, which continues with the countries purchasing drugs through the Pan American Health Organization Strategic Fund. The main challenges in the scaling up of new drugs for DR-TB include low DR-TB detection rate, the slow pace in transitioning to molecular testing and delays in the introduction of new oral short regimens for MDR-TB. The Americas need to accelerate the scale up of new oral treatments, improve detection rates, increase molecular diagnosis of resistance, and ensure the registration and introduction of the shorter treatment regimen in national MDR-TB guidelines.

High-throughput determination of pesticide residues in food commodities by use of ultra-performance liquid chromatography-tandem mass spectrometry.

A rapid, simple, and sensitive multiresidue method for analysis of 53 pesticides in fruit and vegetables by ultra-performance liquid chromatography (UPLC) coupled to triple-quadrupole tandem mass spectrometry (MS-MS) has been developed and validated. Prior to analysis, analytes were extracted by use of buffered QuEChERS (quick, easy, cheap, effective, rugged, safe) methodology without further cleanup for non fatty matrices. Chromatographic conditions were optimised in order to achieve a fast separation in multiple reaction monitoring (MRM) mode. Indeed, more than 50 pesticides can be separated in less then 10 min. Four common representative matrices (cucumber, orange, strawberry, and olive) were selected to investigate the effect of different matrices on recovery and precision. Mean recoveries ranged from 70 to 109% with relative standard deviations lower than 20% for all the pesticides assayed in the four selected matrices. The method has been applied to the analysis of 200 vegetable samples, and imidacloprid was the pesticide most frequently found, with concentrations ranging from 0.01 to 1.00 mg kg(-1). This methodology combines the advantages of both QuEChERS and UPLC-MS-MS producing a very rapid, sensitive, and reliable procedure which can be applied in routine analytical laboratories.

Multicenter study of MTT and resazurin assays for testing susceptibility to first-line anti-tuberculosis drugs.

OBJECTIVE: A multicentre evaluation was performed to assess two rapid low-cost methods, MTT (3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide) and resazurin assays, for testing the susceptibility of Mycobacterium tuberculosis to the first-line anti-tuberculosis drugs rifampicin (RMP), isoniazid (INH), ethambutol (EMB) and streptomycin (SM). METHODS: Thirty coded M. tuberculosis strains were sent to seven laboratories located in Latin America, representing six countries. Each site performed the colorimetric assays, MTT and resazurin, blind for the first-line drugs RMP, INH, EMB and SM. The minimum inhibitory concentration results obtained were compared to the conventional proportion method on Lowenstein-Jensen medium. RESULTS: After establishing the breakpoint concentrations, excellent results were obtained for RMP, INH and EMB, with levels of specificity and sensitivity of between 96% and 99%. CONCLUSION: MTT and resazurin assays are promising, accessible new alternative methods for middle- and low-resource countries that need low-cost methods to perform rapid susceptibility testing of M. tuberculosis to key anti-tuberculosis drugs.

Linfadenitis por mycobacterium incluyendo pacientes infectados por el virus de inmunodeficiencia humana / Mycobacterium lymphadenitis including patients infected with human inmunodefi

El género Mycobacterium provoca infecciones pulmonares y extrapulmonares, de estas últimas predomina la infección ganglionar. Mientras Mycobacterium tuberculosis es el agente causal más importante, en las últimas décadas aumenta la incidencia de otras especies micobacterianas que se han hecho prevalentes en los pacientes positivos al virus de la inmunodeficiencia humana (VIH +) tanto en países desarrollados como en vías de desarrollo. Durante el período enero 2007 hasta diciembre 2009 se procesó en nuestro laboratorio 6540 muestras, 210 muestras fueron obtenidas por biopsia ganglionar, precisamente este constituyó nuestro universo de estudio, 190 (90.4%) muestras se obtuvieron por exéresis quirúrgica, 20 (9.5%) por punción espirativa;17 procedían de pacientes VIH– (8.1%) y 193 procedentes de pacientes VIH+(91.9%). En solo 16 muestras (7.6%) el cultivo BAAR fue positivo; 4 procedentes de pacientes VIH– (25%) y 12 VIH+(75%). La clasificación e identificación micobacteriana demostró la presencia de Mycobacterium tuberculosis en 13 de los casos (81.25%), mientras Mycobacterium avium-intracellulare fue aislado en 3 (18.7%). En los pacientes inmunodeprimidos con linfadenopatía incluidos los pacientes VIH/sida, es muy importante la búsqueda activa de la presencia de BAAR como coinfección oportunista, donde Mycobacterium tuberculosis se mantiene como el agente infeccioso más frecuente, sin embargo la posibilidad de que otras especies micobacterianas también estén presentes no se debe descartar. Nuestro objetivo en este estudio como Laboratorio Nacional de Referencia de TB- Micobacterias fue lograr la caracterización etiológica de linfadenopatías en pacientes en que se sospechaba clínicamente la participación del género Mycobacterium.

Mycobacterium tuberculosis is the most important etiological agent producing pulmonary as well as extrapulmonary infection. During these last decades, the increase in the incidence of infection due to other mycobacteria species is evident. Lymphadenopathy is the most frequent extrapulmonary presentation form of Mycobacterium Genera infection among HIV positive patients either in developed or underdeveloped countries. The aim of this work is to analyze the results obtained during January 2007 - December 2009 in our laboratory. Two hundred ten tissue samples were studied; 190 (90.4%) samples were lymph node biopsied tissues and 20 (9.5%) samples were obtained by fine needle aspiration; 17 were from HIV - patients (8.1%) and 193 from HIV + (91.9%). A total of 16 (7.6%) samples produced a positive culture for BAAR, 4 VIH- (25%) and 12 VIH+ (75%). Classification and identification for mycobacteria confirmed Mycobacterium tuberculosis in 13 of the cases (81.25%), and Mycobacterium avium-intracellulare in three patients (18.7%). The present study once again confirms that BAAR culture has more sensitivity and specificity than histopathologhic studies have. Lymphadenopathy in immunosuppressed patients should by studied for the presence of an BAAR coinfection where M. tuberculosis is still the agent most frequently found, nevertheless, other species of Mycobacteria may be causing infection and should be searched for. Our objective as National Reference Laboratory of Tuberculosis and Mycobacterial was to obtain the etiological characterization of Mycobacterium lymphadenopathy in clinically suspect patients.

Molecular fingerprinting of mycobacterium tuberculosis isolates obtained in havana, cuba, by IS6110 restriction fragment length polymorphism analysis and by the double-repetitive-element PCR method.

Mycobacterium tuberculosis sputum isolates from 38 patients, obtained in the first 6 months of 1997 in Havana, Cuba, were characterized by IS6110 restriction fragment length polymorphism (RFLP) analysis and the double-repetitive-element PCR (DRE-PCR) method. Among 41 strains from 38 patients, 24 and 25 unique patterns, and 5 and 4 cluster patterns, were found by the RFLP and DRE-PCR methods, respectively. Patients within two of these clusters were found to be epidemiologically related, while no relation was observed in patients in the other clusters. The DRE-PCR method is rapid, and it was as discriminating as IS6110 RFLP analysis in identifying an epidemiological association. Its simplicity makes the technique accessible for subtyping of M. tuberculosis strains in laboratories not equipped to perform RFLP analysis.

[Evaluation of an ELISA for the serologic diagnosis of tuberculosis]. / Evaluación de un ELISA para el diagnóstico serológico de tuberculosis.

The use of an ELISA method for the serological diagnosis of tuberculosis was assessed through the study of the presence of circulating IgG antibodies to PPD in 220 serum samples. An 82% sensibility was determined in 50 serum samples from patients with pulmonary tuberculosis, and a specificity of 95.33% in 150 serum samples from apparently healthy subjects. 20 serum samples from patients with disorders other than tuberculosis were included in the study to determine possible cross reactions.

[Buruli ulcer in the Amansi West district, Ashanti Region, Ghana. The Cuban experience. I]. / Ulcera de Buruli en el distrito Amansie West, Región Ashanti, Ghana. Experiencia cubana. I.

A study was made on 105 patients with Buruli ulcer in the Amansie West district, Ashanti Region, Ghana, representing 37.6% of the registered patients. The Tontokrom neighborhood showed the highest prevalence: 84 x 1,000 inhabitants. Predominance of females (54%) was observed. 74.8% did agricultural work and only 3 reported a previous trauma, predominantly with one lesion. Household contacts were identified. Coverage with the BCG vaccine was low. It is concluded that there has been a real increase of the prevalence of Buruli in the region during the last years, especially among children and women. This has become a serious problem due to its invalidating and irreversible sequelae. Measures of control are proposed.