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

Blinded 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.

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.

Tuberculosis Exacerbates HIV-1 Infection through IL-10/STAT3-Dependent Tunneling Nanotube Formation in Macrophages.

The tuberculosis (TB) bacillus, Mycobacterium tuberculosis (Mtb), and HIV-1 act synergistically; however, the mechanisms by which Mtb exacerbates HIV-1 pathogenesis are not well known. Using in vitro and ex vivo cell culture systems, we show that human M(IL-10) anti-inflammatory macrophages, present in TB-associated microenvironment, produce high levels of HIV-1. In vivo, M(IL-10) macrophages are expanded in lungs of co-infected non-human primates, which correlates with disease severity. Furthermore, HIV-1/Mtb co-infected patients display an accumulation of M(IL-10) macrophage markers (soluble CD163 and MerTK). These M(IL-10) macrophages form direct cell-to-cell bridges, which we identified as tunneling nanotubes (TNTs) involved in viral transfer. TNT formation requires the IL-10/STAT3 signaling pathway, and targeted inhibition of TNTs substantially reduces the enhancement of HIV-1 cell-to-cell transfer and overproduction in M(IL-10) macrophages. Our study reveals that TNTs facilitate viral transfer and amplification, thereby promoting TNT formation as a mechanism to be explored in TB/AIDS potential therapeutics.

Human Mycobacterium bovis infection in ten Latin American countries.

The aim of this work was to obtain the best possible estimate of the relevance of bovine tuberculosis (BTB) in humans in Argentina, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, Peru, Uruguay and Venezuela. Sources of information were a questionnaire filled by the participant laboratories, and a search of published literature (1970-2007). Only four of these countries reported bacteriologically confirmed cases of BTB in humans. Most of these were diagnosed in Argentina, where the mean percentage of Mycobacterium bovis cases in relation to those due to Mycobacterium tuberculosis (2000-2006) ranged from 0.34% to 1.0%, according to the region. A slowly decreasing trend was observed in non HIV as well as in HIV/AIDS patients in Buenos Aires. In most of these countries, the low coverage of culture methods, especially of those including pyruvate-containing media, appropriate to isolate M. bovis, contributes to an underestimate of the problem. It was confirmed that BTB in humans exists, even though its relevance seems to be low. Milk pasteurization, sanitary controls to dairy products, and meat inspection at slaughterhouses contribute to the protection of human health. However, occupational aerogenous exposure to TB cattle and their carcasses remains a source of infection in the region.

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

OBJECTIVE: To assess a LED-fluorescence microscopy (LED-FM) capacitation program for the training of laboratory technicians without previous experience in FM. METHODS: We evaluated a teaching program that consists of a three-day course followed by an "in situ" two-month phase in which technicians acquired skills without the help of a FM expert; in order to gain confidence to recognize auramine-stained bacillus, during this phase, technicians examined duplicate slides stained by Ziehl Neelsen (ZN) and FM in a unblinded way. Technicians with acceptable performance, continued with a blinded-training period. Testing panels and rechecking process were used to evaluate proficiency after different length of experience. RESULTS: Post-course panel results showed that 70% of trainees made Low False Positive errors (LFPs). Analysis of two other panels showed that LFPs significantly decreased (Chi-squared test, p<0.05) as the "in situ" training phase progressed. Processing at least three slides/day was associated with acceptable performance. During the blinded-training period, results of the rechecking process showed that sensitivity (96.8%) and specificity (99.8%) levels were satisfactory. CONCLUSION: Moderate training (a three-day course) is not enough to make technicians proficient in LED-FM; however, great ability can be reached after a short "in situ" training phase even without the presence of experienced staff available in field to review doubtful results. Training was more effective in services with a minimum workload of 750 slides/year.

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 mCherrybomb ϕ 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 mCherrybomb Φ 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 mCherrybomb Φ 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.

Formation of Foamy Macrophages by Tuberculous Pleural Effusions Is Triggered by the Interleukin-10/Signal Transducer and Activator of Transcription 3 Axis through ACAT Upregulation.

The ability of Mycobacterium tuberculosis (Mtb) to persist in its human host relies on numerous immune evasion strategies, such as the deregulation of the lipid metabolism leading to the formation of foamy macrophages (FM). Yet, the specific host factors leading to the foamy phenotype of Mtb-infected macrophages remain unknown. Herein, we aimed to address whether host cytokines contribute to FM formation in the context of Mtb infection. Our approach is based on the use of an acellular fraction of tuberculous pleural effusions (TB-PE) as a physiological source of local factors released during Mtb infection. We found that TB-PE induced FM differentiation as observed by the increase in lipid bodies, intracellular cholesterol, and expression of the scavenger receptor CD36, as well as the enzyme acyl CoA:cholesterol acyl transferase (ACAT). Importantly, interleukin-10 (IL-10) depletion from TB-PE prevented the augmentation of all these parameters. Moreover, we observed a positive correlation between the levels of IL-10 and the number of lipid-laden CD14+ cells among the pleural cells in TB patients, demonstrating that FM differentiation occurs within the pleural environment. Downstream of IL-10 signaling, we noticed that the transcription factor signal transducer and activator of transcription 3 was activated by TB-PE, and its chemical inhibition prevented the accumulation of lipid bodies and ACAT expression in macrophages. In terms of the host immune response, TB-PE-treated macrophages displayed immunosuppressive properties and bore higher bacillary loads. Finally, we confirmed our results using bone marrow-derived macrophage from IL-10-/- mice demonstrating that IL-10 deficiency partially prevented foamy phenotype induction after Mtb lipids exposure. In conclusion, our results evidence a role of IL-10 in promoting the differentiation of FM in the context of Mtb infection, contributing to our understanding of how alterations of the host metabolic factors may favor pathogen persistence.

Tuberculous meningitis in HIV-infected patients: drug susceptibility and clinical outcome.

The objective of this study was to identify prognostic factors of death in patients with tuberculous meningitis (TM) and show the impact of infection by multidrug-resistant strains on the outcome of this disease. We retrospectively analysed clinical charts of HIV-infected patients with culture-confirmed TM attending our institution during 1996-2004. The following variables were associated with death during hospitalization: neurological signs at admission, a CD4 T-cell count less than 50 cells/microl and infection by multidrug-resistant strains.

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

INTRODUCTION: Light-emitting diode fluorescence microscopy (LED-FM) has been endorsed by the World Health Organization (WHO) for tuberculosis diagnosis, but its accuracy in HIV-infected patients remains controversial, and only some few studies have explored procedural factors that may affect its performance. OBJECTIVE: To evaluate the performance of LED-FM for tuberculosis diagnosis in patients with and without HIV infection using a newer, less expensive LED lamp. MATERIALS AND METHODS: We compared the performance of LED-FM and Ziehl-Neelsen (ZN) microscopy on respiratory specimen smears from tuberculosis (TB) suspects and patients on treatment examined by different technicians blinded for HIV-status and for the result of the comparative test. We analyzed the effect of concentrating specimens prior to microscopy using different examination schemes and user-appraisal of the LED device. RESULTS: Of the 6,968 diagnostic specimens collected, 869 (12.5%) had positive Mycobacterium tuberculosis cultures. LED-FM was 11.4% more sensitive than ZN (p;0.01). Among HIV-positive TB patients, sensitivity differences between LED-FM and ZN (20.6%) doubled the figure obtained in HIVnegative patients or in those with unknown HIV status (9.3%). After stratifying by direct and concentrated slides, the superiority of LED-FM remained. High specificity values were obtained both with LED-FM(99.9%) and ZN (99.9%).The second reading of a sample of slides showed a significantly higher positive detection yield using 200x magnification (49.4 %) than 400x magnification (33.8%) (p;0.05). The LEDdevice had a very good acceptance among the technicians. CONCLUSION: LED-FM better performance compared with ZN in HIV-infected patients and user-appraisal support the rapid roll-out of LED-FM. Screening at 200x magnification was essential to achieve LEDFM increased sensitivity.

[Multidrug-resistant tuberculosis in AIDS patients at the beginning of the millennium]. / Tuberculosis multirresistente en pacientes con SIDA a comienzos del milenio.

AIDS-related multidrug-resistant tuberculosis (MDRTB) emerged during the 90s in several countries around the world. In Argentina, the most notorious outbreak was documented in the Hospital Muñiz, which is still undergoing its aftermaths. In order to evaluate the situation in this hospital regarding MDRTB, we analysed clinical, demographic and epidemiological traits of the 53 male MDRTB-aids patients admitted during 2001-2003 at a ward especially dedicated to their isolation. Patients' mean age was 32 years, 70% lived in Buenos Aires suburbs. A history of illicit drug users or imprisonment was recorded in 68% and 26% of the patients, respectively. Severe immunodepression (CD4+ count < 100/microl) was found in 88% of the patients and 58% died. Mortality was associated with non-adherence to treatment and co-morbidity, but not with the genotype of the "M" strain, responsible for the original outbreak. Of 40 cases available for restriction fragment length polymorphism (RFLP), 29 (72.5%) resulted in cluster. RFLP patterns of 24 matched the "M" genotype. In this study, resistance to 5 or 6 drugs was found to be an indicator of disease due to the "M" strain. The "M" genotype associated significantly to previous admission at the Hospital Muñiz or imprisonment. In brief, 14 years after the detection of the first MDRTB-aids case, we report here the persistence and predominance of the original outbreak strain at the hospital. Stronger TB infection control measures are urgently needed in hospitals and jails in order to strengthen the declining trend of the MDRTB observed in our country towards the end of the last decade.

First series of patients with XDR and pre-XDR TB treated with regimens that included meropenen-clavulanate in Argentina.

XDR (extensively drug-resistant) and pre-XDR tuberculosis (TB) seriously compromise prognosis and treatment possibilities, and inevitably require the use of group V drugs (World Health Organization). The progress of all patients with XDR and pre-XDR TB seen in a specialized unit during 2012 and 2013 and treated with regimens that included at least 6 months of meropenem-clavulanate (MPC), capreomycin, moxifloxacin, linezolid, clofazimine, high-dose isoniazid, PAS, and bedaquiline in 1 case, were retrospectively analysed. Ten patients were treated, 9 with an extensive pattern of resistance to at least 6 drugs, and 1 because of adverse reactions and drug interactions leading to a similar situation. Eight of the 10 patients treated achieved bacteriological sputum conversion (2 consecutive negative monthly cultures) over a period of 2-7 months, while 2 died. No adverse reactions attributable to prolonged administration of MPC were observed.

[Mastitis due to Mycobacterium fortuitum in an HIV negative patient]. / Mastitis por Mycobacterium fortuitum en una paciente HIV negativa.

A case of a 39 year old HIV negative female patient with a Mycobacterium fortuitum mastitis without previous pathogenic history is reported. She was treated on the bases of drug-susceptibility testing and bibliographic empirical evidence with kanamycin, doxicicline, ciprofloxacin and trimetoprim-sulfametoxazol. A complete remission of her lesions was obtained after 15 months of treatment. Lesions due to this rapidly growing mycobacterium, diagnosis and treatment are commented.

Training tuberculosis laboratory workers in LED-fluorescence microscopy: experience learned in Argentina / Capacitación de trabajadores de laboratorios de tuberculosis en microscopia de fluorescencia LED: experiencia en Argentina

ABSTRACT Objective To assess a LED-fluorescence microscopy (LED-FM) capacitation program for the training of laboratory technicians without previous experience in FM. Methods We evaluated a teaching program that consists of a three-day course followed by an "in situ" two-month phase in which technicians acquired skills without the help of a FM expert; in order to gain confidence to recognize auramine-stained bacillus, during this phase, technicians examined duplicate slides stained by Ziehl Neelsen (ZN) and FM in a unblinded way. Technicians with acceptable performance, continued with a blinded-training period. Testing panels and rechecking process were used to evaluate proficiency after different length of experience. Results Post-course panel results showed that 70% of trainees made Low False Positive errors (LFPs). Analysis of two other panels showed that LFPs significantly decreased (Chi-squared test, p<0.05) as the "in situ" training phase progressed. Processing at least three slides/day was associated with acceptable performance. During the blinded-training period, results of the rechecking process showed that sensitivity (96.8%) and specificity (99.8%) levels were satisfactory. Conclusion Moderate training (a three-day course) is not enough to make technicians proficient in LED-FM; however, great ability can be reached after a short "in situ" training phase even without the presence of experienced staff available in field to review doubtful results. Training was more effective in services with a minimum workload of 750 slides/year.(AU)

RESUMEN Objetivo Evaluar un programa de capacitación en microscopía de fluorescencia LED (MF-LED) para el entrenamiento de técnicos de laboratorio sin experiencia en MF. Métodos Se evaluó un programa de capacitación que consiste en un curso de tres días seguido de dos meses de entrenamiento «in situ¼, en donde los técnicos adquirieron habilidades sin presencia de un experto en la práctica diaria; para alcanzar confianza en el reconocimiento del bacilo, los técnicos, durante estos meses, examinaron en forma «no cegada¼ extendidos duplicados teñidos por Ziehl Neelsen (ZN) y MF. Aquellos laboratoristas que lograron rendimiento aceptable continuaron su entrenamiento «a ciegas¼. Su desempeño fue evaluado en distintos períodos del entrenamiento mediante paneles de láminas y relectura de extendidos. Resultados Los resultados de un panel posterior al curso mostraron que 70% de los participantes cometieron errores falsos positivos bajos (FPB). Dos paneles posteriores evidenciaron que los FPB disminuían significativamente (prueba de Chi cuadrado, p<0.05) a medida que el entrenamiento avanzaba. El procesamiento de al menos tres extendidos/ día se asoció con desempeño aceptable. Durante el período a ciegas, la relectura de láminas evidenció que la sensibilidad (96,8%) y especificidad (99,8%) fueron satisfactorias. Conclusiones Una capacitación moderada (curso de tres días) no es suficiente para adquirir competencia en MF-LED; sin embargo, se puede alcanzar habilidad después de una corta capacitación «in situ¼, incluso si no hay personal con experiencia disponible en el servicio para revisar los resultados dudosos diariamente. El entrenamiento fue más efectivo en servicios con carga de trabajo mínima de 750 extendidos/año.(AU)

Performance of LED fluorescence microscopy for the detection of acid-fast bacilli from respiratory samples in peripheral laboratories in Argentina / Rendimiento de la microscopía de fluorescencia LED para la detección de bacilos ácido-alcohol resistentes en muestras respiratorias en laboratorios periféricos de Argentina

ABSTRACT Introduction: Light-emitting diode fluorescence microscopy (LED-FM) has been endorsed by the World Health Organization (WHO) for tuberculosis diagnosis, but its accuracy in HIV-infected patients remains controversial, and only some few studies have explored procedural factors that may affect its performance. Objective: To evaluate the performance of LED-FM for tuberculosis diagnosis in patients with and without HIV infection using a newer, less expensive LED lamp. Materials and methods: We compared the performance of LED-FM and Ziehl-Neelsen (ZN) microscopy on respiratory specimen smears from tuberculosis (TB) suspects and patients on treatment examined by different technicians blinded for HIV-status and for the result of the comparative test. We analyzed the effect of concentrating specimens prior to microscopy using different examination schemes and user-appraisal of the LED device. Results: Of the 6,968 diagnostic specimens collected, 869 (12.5%) had positive Mycobacterium tuberculosis cultures. LED-FM was 11.4% more sensitive than ZN (p<0.01). Among HIV-positive TB patients, sensitivity differences between LED-FM and ZN (20.6%) doubled the figure obtained in HIV-negative patients or in those with unknown HIV status (9.3%). After stratifying by direct and concentrated slides, the superiority of LED-FM remained. High specificity values were obtained both with LED-FM (99.9%) and ZN (99.9%).The second reading of a sample of slides showed a significantly higher positive detection yield using 200x magnification (49.4 %) than 400x magnification (33.8%) (p<0.05). The LED-device had a very good acceptance among the technicians. Conclusion: LED-FM better performance compared with ZN in HIV-infected patients and user-appraisal support the rapid roll-out of LED-FM. Screening at 200x magnification was essential to achieve LED-FM increased sensitivity.

RESUMEN 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.

Primera serie de pacientes con TB-XDR y pre-XDR tratados con esquemas que incluyeron meropenem-clavulanato en Argentina / First Series of Patients With XDR and Pre-XDR TB Treated With Regimens That Included Meropenen-clavulanate in Argentina

La tuberculosis extensamente resistente (TB-XDR) y pre-XDR comprometen seriamente el pronóstico de la enfermedad, y su tratamiento requiere inevitablemente el uso de fármacos del grupo V (Organización Mundial de la Salud [OMS]). Se analizó retrospectivamente la evolución de todos los pacientes con TB pre-XDR y XDR asistidos en un servicio especializado durante 2012 y 2013, medicados con regímenes que incluyeron por lo menos 6 meses de meropenem-clavulanato (MPC), capreomicina, moxifloxacina, linezolid, clofazimina, isoniacida en alta dosis, PAS y en un caso bedaquilina. Fueron tratados 10 pacientes, 9 de ellos con un extenso patrón de resistencia a un mínimo de 6 fármacos y uno por reacciones adversas e interacciones medicamentosas que generaron una situación análoga. Ocho de los 10 pacientes tratados, hicieron la conversión bacteriológica del esputo (2 cultivos mensuales consecutivos negativos) en un lapso de 2 a 7 meses, en tanto que 2 fallecieron. No se observaron reacciones adversas atribuibles a la administración prolongada del MPC

XDR (extensively drug-resistant) and pre-XDR tuberculosis (TB) seriously compromise prognosis and treatment possibilities, and inevitably require the use of group V drugs (World Health Organization). The progress of all patients with XDR and pre-XDR TB seen in a specialized unit during 2012 and 2013 and treated with regimens that included at least 6 months of meropenem-clavulanate (MPC), capreomycin, moxifloxacin, linezolid, clofazimine, high-dose isoniazid, PAS, and bedaquiline in 1 case, were retrospectively analyzed. Ten patients were treated, 9 with an extensive pattern of resistance to at least 6 drugs, and 1 because of adverse reactions and drug interactions leading to a similar situation. Eight of the 10 patients treated achieved bacteriological sputum conversion (2 consecutive negative monthly cultures) over a period of 2–7 months, while 2 died. No adverse reactions attributable to prolonged administration of MPC were observed

[Evaluation of the control measures adopted against an epidemic of AIDS-related multidrug-resistant tuberculosis in a Latin-American hospital]. / Evaluación de las medidas de control adoptadas frente a la epidemia de tuberculosis multirresistente asociada al sida en un hospital hispanoamericano.

BACKGROUND: Since 1992 AIDS-related multidrug-resistant tuberculosis (MDRTB) has been detected among patients admitted to the Hospital Muñiz in Buenos Aires (Argentina). The aim of the present study was to evaluate the effectiveness of the control measures adopted against the nosocomial spread of MDRTB/AIDS, which affected 803 patients between 1992 and 2002. METHODS: An action plan was applied that included bacilloscopy screening on admission, isolation rooms for patients with TB/AIDS, an isolation ward for patients with MDRTB/AIDS, a radiometric method for the diagnosis of multidrug-resistance, a reserve supply of second line drugs, and respiratory protection for health care workers. RESULTS: Between 1995 and 2002, a statistically significant decreasing trend in cases of MDRTB/AIDS and admissions for TB/AIDS was observed (33.9% vs 80.5%). Mortality among patients with MDRTB/AIDS also significantly decreased. Bacilloscopy screening allowed the diagnosis of 63.4% of patients admitted with TB/AIDS. Respiratory isolation facilities and effective treatment of patients with MDRTB diagnosed through the radiometric method were progressively implemented. Admission of patients with AIDS showed no significant variations throughout the study period. The CD41 count of patients requiring admission did not vary significantly. CONCLUSION: The nosocomial epidemic curve of MDRTB in patients with AIDS significantly decreased, despite the persistence of susceptible patients with low CD41 levels. The decreasing tendency of MDRTB/AIDS cases could be attributed to the impact of the control measures implemented.

Multidrug-resistant tuberculosis in HIV-negative patients, Buenos Aires, Argentina.

Initial multidrug-resistant (MDR) tuberculosis (TB) in HIV-negative patients treated at a Buenos Aires referral hospital from 1991 to 2000 was examined by using molecular clustering of available isolates. Of 291 HIV-negative MDRTB patients, 79 were initially MDR. We observed an ascending trend of initial MDRTB during this decade (p=0.0033). The M strain, which was responsible for an institutional AIDS-associated outbreak that peaked in 1995 to 1997, caused 24 of the 49 initial MDRTB cases available for restriction fragment length polymorphism. Of those, 21 were diagnosed in 1997 or later. Hospital exposure increased the risk of acquiring M strain-associated MDRTB by approximately two and a half times. The emergence of initial MDRTB among HIV-negative patients after 1997 was apparently a sequel of the AIDS-related outbreak. Because the prevalence of M strain-associated disease in the study population did not level out by the end of the decade, further expansion of this disease is possible.

Tuberculosis extensamente resistente (XDR-TB) en Argentina: aspectos destacables epidemiológicos, bacteriológicos, terapéuticos y evolutivos / Extensively resistant tuberculosis (XDR-TB) in Argentina: epidemiology, bacteriology, therapy and outcome

La XDR-TB (resistente a isoniazida, rifampicina, alguna fluoroquinolona y al menos una entre kanamicina, amikacina o capreomicina), ha causado efectos devastadores en pacientes con SIDA y es prácticamente incurable. Se presentan 12 casos de localización pulmonar en pacientes no SIDA. Se trataron con esquemas que incluyeron en todos linezolid y en 9 moxifloxacino, todos negativizaron el examen directo y cultivo del esputo. Nueve pacientes cumplieron criterios de curación, 1 está aún en tratamiento y 2 abandonaron. Ocho pacientes presentaron efectos adversos, en solo 1 caso debió suspenderse la tioridazina. La utilización de linezolid, moxifloxacina y tioridazina han contribuido a la evolución satisfactoria de estos pacientes. Estos fármacos son considerados de utilidad en la serie reportada, debiendo ser utilizados en centros especializados con experiencia en el manejo de la TB MR y XDR-TB.

The XDR-TB (resistant to isoniazid, rifampiN, fluorquinolone and at least of the following: kanamycina, amikacyna or capreomycin), has caused devastating effects in patients with AIDS and is practically incurable. Twelve cases of pulmonary XDR-TB in non AIDS are described. All were treated with schemes that included linezolid in all and moxifloxacin in 9, all respiratory specimens became negative. Nine patients fulfilled healing criteria, 1 is still under treatment and 2 abandoned the therapy. Eight patients presented adverse effects, thioridazine was stopped in only one patient. Linezolid, moxifloxacin and tioridazin contributed to the satisfactory evolution of these patients. These drugs were considered useful in the reported series of cases and should be used in specialized centres with experience in the management of MR TB and XDR-TB.

Tuberculosis multirresistente en pacientes con SIDA a comienzos del milenio / Multidrug-resistant tuberculosis in AIDS patients at the beginning of the millennium

La tuberculosis multirresistente (TBMR) asociada al sida emergió durante los años 90 en varios países del mundo. En Argentina, el brote más importante se originó en el Hospital Muñiz y susconsecuencias persisten hasta ahora. Con el objeto de evaluar la situación de la TBMR en este hospital, analizamoslas características clínico-demográfico-epidemiológicas de los 53 pacientes masculinos con TBMR/sida internados por primera vez en el trienio 2001-2003 con relación al genotipo del polimorfismo de longitud de fragmentos de restricción (RFLP) IS6110 de los aislamientos. La edad promedio de los pacientes fue 32 años, 37 (70%) residían en el conurbano bonaerense, 36 (68%) eran usuarios de drogas ilícitas y 14 (26.4%) tenían antecedentes carcelarios. El 88% presentó grave inmunodepresión (CD4+<100/μl) y el 58.5% falleció. La mortalidadse asoció a baja adherencia al tratamiento y a comorbilidades, pero no a enfermedad por Mycobacteriumtuberculosis cepa “M”, causante del brote original. De los 40 casos analizados por RFLP, 29 (72.5%) conformaron clusters y 24 presentaban el genotipo “M”. La resistencia a 5 o 6 drogas resultó un indicador de enfermedad por esa cepa. El genotipo “M” se asoció significativamente a internaciones previas en el Hospital Muñiz oencarcelamiento. En síntesis, 14 años después de ocurrido el primer caso de TBMR/sida, se constata la persistenciay predominancia en el hospital de la cepa responsable del brote. Se requiere una intensificación de las medidas de control de la diseminación institucional de la tuberculosis para consolidar la tendencia decrecientede la TBMR observada en el país en la última década

Aids-related multidrug-resistant tuberculosis (MDRTB) emerged during the 90s in several countries aroundthe world. In Argentina, the most notorious outbreak was documented in the Hospital Muñiz, which is still undergoing its aftermaths. In order to evaluate the situation in this hospital regarding MDRTB, we analysed clinical,demographic and epidemiological traits of the 53 male MDRTB-aids patients admitted during 2001-2003 at award especially dedicated to their isolation. Patients’ mean age was 32 years, 70% lived in Buenos Aires suburbs. A history of illicit drug users or imprisonment was recorded in 68% and 26% of the patients, respectively.Severe immunodepression (CD4+ count <100/μl) was found in 88% of the patients and 58% died. Mortality wasassociated with non-adherence to treatment and co-morbidity, but not with the genotype of the “M” strain, responsible for the original outbreak. Of 40 cases available for restriction fragment length polymorphism (RFLP),29 (72.5%) resulted in cluster. RFLP patterns of 24 matched the “M” genotype. In this study, resistance to 5 or 6 drugs was found to be an indicator of disease due to the “M” strain. The “M” genotype associated significantlyto previous admission at the Hospital Muñiz or imprisonment. In brief, 14 years after the detection of the firstMDRTB-aids case, we report here the persistence and predominance of the original outbreak strain at the hospital.Stronger TB infection control measures are urgently needed in hospitals and jails in order to strengthenthe declining trend of the MDRTB observed in our country towards the end of the last decade

Evaluación de las medidas de control adoptadas frente a la epidemia de tuberculosis multirresistente asociada al sida en un hospital hispanoamericano / Evaluation of the control measures adopted against an epidemic of AIDS-related multidrug-resistant tuberculosis in a latin-american hospital

Desde 1992 se detectaron pacientes con tuberculosis multirresistente (TBMR) asociada al sida internados en el Hospital Muñiz (Buenos Aires). El objetivo del trabajo es evaluar la eficacia de las medidas adoptadas frente a la expansión nosocomial de la TBMR/sida, que afectó a 803 enfermos entre 1992-2002. Métodos. Se aplicó un plan de acción que incluyó: cribado baciloscópico de admisión, habitaciones de aislamiento para TB/sida, sala de aislamiento para TBMR/sida, diagnóstico de multirresistencia mediante método radiométrico; banco de fármacos de segunda línea y protección respiratoria del personal de salud. Resultados. Entre 1995 y 2002, se observó una tendencia estadísticamente significativa en la disminución de casos de TBMR/sida y de los internamientos por TB/sida (33,9% frente a 80,5%, respectivamente), así como una disminución significativa en la mortalidad de los primeros. El cribado baciloscópico permitió diagnosticar el 63,4% de los casos de TB/sida internados. Progresivamente fueron empleados los recursos de aislamiento respiratorio y tratamiento eficaz de los casos de TBMR diagnosticados por método radiométrico. Respecto de la población susceptible, el ingreso de pacientes con sida al hospital no varió significativamente a lo largo del período estudiado, tampoco lo hizo el recuento de linfocitos T CD41 de los pacientes que requirieron internamiento. Conclusión. Se observó una disminución significativa de la curva epidémica nosocomial de TBMR en pacientes con sida, pese a la persistencia de pacientes susceptibles con bajo nivel de linfocitos T CD41. Se considera que esta evolución decreciente de la TBMR/sida puede ser atribuida al impacto de las medidas de control implementadas (AU)

Since 1992 AIDS-related multidrug-resistant tuberculosis (MDRTB) has been detected among patients admitted to the Hospital Muñiz in Buenos Aires (Argentina). The aim of the present study was to evaluate the effectiveness of the control measures adopted against the nosocomial spread of MDRTB/AIDS, which affected 803 patients between 1992 and 2002. Methods. An action plan was applied that included bacilloscopy screening on admission, isolation rooms for patients with TB/AIDS, an isolation ward for patients with MDRTB/AIDS, a radiometric method for the diagnosis of multidrug-resistance, a reserve supply of second line drugs, and respiratory protection for health care workers. Results. Between 1995 and 2002, a statistically significant decreasing trend in cases of MDRTB/AIDS and admissions for TB/AIDS was observed (33.9% vs 80.5%). Mortality among patients with MDRTB/AIDS also significantly decreased. Bacilloscopy screening allowed the diagnosis of 63.4% of patients admitted with TB/AIDS. Respiratory isolation facilities and effective treatment of patients with MDRTB diagnosed through the radiometric method were progressively implemented. Admission of patients with AIDS showed no significant variations throughout the study period. The CD41 count of patients requiring admission did not vary significantly. Conclusion. The nosocomial epidemic curve of MDRTB in patients with AIDS significantly decreased, despite the persistence of susceptible patients with low CD41 levels. The decreasing tendency of MDRTB/AIDS cases could be attributed to the impact of the control measures implemented (AU)