Fluoromycobacteriophages can detect viable Mycobacterium tuberculosis and determine phenotypic rifampicin resistance in 3-5 days from sputum collection

The World Health Organization (WHO) estimates that 40% of tuberculosis (TB) cases are not diagnosed and treated correctly. Even though there are several diagnostic tests available in the market, rapid, easy, inexpensive detection, and drug susceptibility testing (DST) of Mycobacterium tuberculosis is still of critical importance specially in low and middle-income countries with high incidence of the disease. In this work, we have developed a microscopy-based methodology using the reporter mycobacteriophage mCherrybombΦ for detection of Mycobacterium spp. and phenotypic determination of rifampicin resistance within just days from sputum sample collection. Fluoromycobacteriophage methodology is compatible with regularly used protocols in clinical laboratories for TB diagnosis and paraformaldehyde fixation after infection reduces biohazard risks with sample analysis by fluorescence microscopy. We have also set up conditions for discrimination between M. tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM) strains by addition of p-nitrobenzoic acid (PNB) during the assay. Using clinical isolates of pre-XDR and XDR-TB strains from this study, we tested mCherrybombΦ for extended DST and we compared the antibiotic resistance profile with those predicted by whole genome sequencing. Our results emphasize the utility of a phenotypic test for M. tuberculosis extended DST. The many attributes of mCherrybombΦ suggests this could be a useful component of clinical microbiological laboratories for TB diagnosis and since only viable cells are detected this could be a useful tool for monitoring patient response to treatment.Fil: Rondon Salazar, Liliana. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Urdániz, Estefanía. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Latini, Cecilia. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: Payaslian, Florencia Pía. Universidad de Buenos Aires; ArgentinaFil: Matteo, Mario. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; ArgentinaFil: SOSA, EZEQUIEL. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Fernández Do Porto, Darío Augusto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Turjanski, Adrian. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Nemirovsky, Sergio Ivan. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Hatfull, Graham F.. University of Pittsburgh at Johnstown; Estados UnidosFil: Poggi, Susana. University of Pittsburgh; Estados UnidosFil: Piuri, Mariana. Gobierno de la Ciudad de Buenos Aires. Hospital de Infecciosas "Dr. Francisco Javier Muñiz"; Argentin

LED fluorescence microscopy in the diagnosis of tuberculosis: Fading and restaining of smears for external quality assessment

AbstractBlinded rechecking is a method proposed for external quality assurance (EQA) of auramine-stained acid-fast bacilli (AFB) smears using fluorescence microscopy (FM), however, this procedure is not well developed and slides fading over time could compromise its implementation. Since bleaching of fluorescent molecules involves temperature-dependent chemical reactions, it is likely that low temperatures could slow down this process. We stored auramine-stained slides under different environmental conditions, including −20°C, and examined them over time. The slides stored in all the environments faded. At −20°C, fading was not reduced in relation to room temperature. Restaining and re-examining smears after five months showed that the slides containing saliva and storage at −20°C were associated with failure in AFB reappearance. In conclusion, the practice of freezing slides until they are viewed should be discouraged as it has a negative effect on blinded rechecking by reducing reading concordance after restaining. Specimen quality should be considered when interpreting FM-EQA results

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

When women enter male-dominated territories in the platform economy: gender inequalities among drivers and riders in Argentina

Platform labour, especially when it comes to its flexible schedules, may represent a job insertion possibility and a source of income for many women. However, such opportunities are not exempted from gender bias. This article inspects how the expansion of the platform economy affects gender inequalities by focusing on two platform occupations: ride-hailing and delivery services. First, it investigates gender gaps in terms of working hours and earnings via linear regression as well as their determinants. Second, qualitative data further deepen the analysis of female riders’ and drivers’ experience in male-dominated territories, exploring how it is perceived and endured by workers. This paper is based on qualitative and quantitative data collected in the metropolitan area of Buenos Aires between 2019 and 2021. The analysis suggests that the gender-differentiated economic performance of riders and drivers is associated with demographic and on-the-job characteristics, implying restrictions for women workers in terms of how long, where, and when they can work. Algorithmic management further reinforces these initial female disadvantages, through tools such as scoring systems, dynamic pricing, and selective work allocation. The article concludes by providing some insights into a gender-transformative approach to the future regulation of these activities.Fil: Micha, Ariela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento; ArgentinaFil: Poggi, Cecilia. University of Sussex; Reino UnidoFil: Pereyra, Francisca. Universidad Nacional de General Sarmiento; Argentin

Training tuberculosis laboratory workers in LED-fluorescence microscopy: experience learned in Argentina

Fil: Imaz, María S. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Respiratorias; Argentina.Fil: Allassia, Sonia. Dirección de Bioquímica de la Municipalidad de Rosario. Rosario; Argentina.Fil: Aranibar, Mónica. Hospital San Roque. Jujuy; Argentina.Fil: Gunia, Alba M. Laboratorio Central de Salud Pública. Chaco; Argentina.Fil: Poggi, Susana. Hospital F.J. Muñiz. CABA; Argentina.Fil: Togneri, Ana M. Hospital Interzonal General de Agudos «Evita». Lanús, Buenos Aires; Argentina.Fil: Wolff, Lidia. Hospital Rawson. Córdoba; Argentina.To assess a LED-fluorescence microscopy (LED-FM) capacitation program for the training of laboratory technicians without previous experience in FM

Molecular Epidemiology of Mycobacterium tuberculosis, Buenos Aires, Argentina

To analyze the molecular epidemiology of Mycobacterium tuberculosis strains at a hospital in Buenos Aires, Argentina, and mutations related to multidrug-resistant and extensively drug-resistant tuberculosis, we conducted a prospective case–control study. Our findings reinforce the value of incorporating already standardized molecular methods for rapidly detecting resistance

Platform labour in contexts of high informality: Any improvement for workers? A critical assessment based on the case of Argentina

The article analyses the effects of digital labour platforms in a context characterised by high informality, exploring the way platforms may or may not imply a disruption in this respect. To do so, it examines the labour transitions that lead to platform labour, taking into account the formal status of workers before and after joining platforms, as well as their evaluation of resulting labour conditions. The article relies on a quantitative survey and in depth interviews for three on-demand occupations in the Buenos Aires Metropolitan Area, ride-hailing, home repairs and domestic service. Results show that a platform´s influence on the formal status of workers (and their assessment of it) is highly contingent upon: the platform´s business model, including the legal status that may be used to integrate the workforce, the pre-existing formal/informal dynamics within the occupation and the general labour market situation.Fil: Filipetto, Sonia Marina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Micha, Ariela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Pereyra, Francisca. Universidad Nacional de General Sarmiento. Instituto de Ciencias; ArgentinaFil: Poggi, Cecilia. No especifíca;Fil: Trombetta, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentin

Performance of LED fluorescence microscopy for the detection of acid-fast bacilli from respiratory samples in peripheral laboratories in Argentina

Fil: Imaz, María. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Respiratorias; Argentina.Fil: Allassia, Sonia. Dirección de Bioquímica de la Municipalidad de Rosario, Rosario; Argentina.Fil: Aranibar, Mónica. Hospital San Roque, San Salvador de Jujuy; Argentina.Fil: Gunia, Alba. Laboratorio Central de Salud Pública, Resistencia; Argentina.Fil: Poggi, Susana. Hospital “Dr. Francisco Javier Muñiz”, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Togneri, Ana. Hospital Interzonal General de Agudos “Evita”, Lanús; Argentina.Fil: Wolff, Lidia. Hospital Rawson, Córdoba; Argentina.Fil: Group of Implementation of Fluorescence; Argentina.Introducción. La microscopía de fluorescencia con lámpara LED (MF-LED) ha sido recomendada por la Organización Mundial de la Salud (OMS) para el diagnóstico de la tuberculosis, pero su precisión en pacientes con HIV continúa siendo controversial y en pocos estudios se han explorado los factores metodológicos que pueden afectar su utilidad. Objetivo. Evaluar el rendimiento de la MF-LED en el diagnóstico de la tuberculosis en pacientes con HIV y sin él mediante un novedoso dispositivo LED. Materiales y métodos. Se comparó el rendimiento de la MF-LED y la microscopía en frotis de muestras respiratorias con tinción de Ziehl-Neelsen (M-ZN) examinados por técnicos cegados en cuanto al estado de HIV y el resultado de la prueba comparativa. Se analizó el efecto de concentrar muestras antes de la microscopía, usar diferentes esquemas de observación y la valoración con el dispositivo LED. Resultados. De las 6.968 muestras recolectadas, 869 (12,5 %) resultaron con cultivo positivo para Mycobacterium tuberculosis. La MF-LED fue 11,4 % más sensible que la M-ZN (p<0,01). Entre los pacientes con tuberculosis positivos para HIV, la diferencia de sensibilidad entre la MF-LED y la M-ZN (20,6 %) duplicó la cifra obtenida en pacientes negativos para HIV o con estatus desconocido (9,3 %). Al estratificar los frotis en directos y concentrados, se mantuvo la superioridad de la MF-LED. Las especificidades de la MF-LED (99,9 %) y la M-ZN (99,9 %) resultaron elevadas. La lectura de una muestra de frotis mostró una positividad significativamente mayor con un aumento de 200X (49,4 %) que con uno de 400X (33,8 %) (p<0,05). El dispositivo LED tuvo una buena aceptación entre los técnicos. Conclusión. Debido al mejor desempeño de la MF-LED comparada con la M-ZN en pacientes con HIV y su fácil utilización, se recomienda su adopción. La utilización del aumento de 200X fue esencial para el incremento de la sensibilidad de la MF-LED