Combination of commercially available molecular assays and culture based methods in diagnosis of tuberculosis and drug resistant tuberculosis

ABSTRACT Early diagnosis of tuberculosis is of major clinical importance. Among 4733 clinical specimens collected from 3363 patients and subjected to Ziehl-Neelsen microscopy, 4109 were inoculated onto Löwenstein-Jensen slants and 3139 in Bactec/9000MB. Polymerase Chain Reaction (PCR) was performed in 3139 specimens, whereas, a genotypic assay was directly applied in 93 Mycobacterium tuberculosis complex PCR-positive for isoniazid and rifampicin resistance detection specimens (GenoType MTBDRplus). Recovered M. tuberculosis isolates (64) as well as, 21 more sent from Regional Hospitals were tested for antimycobacterial resistance with a phenotypic (manual MGIT-SIRE) and a genotypic assay (GenoType MTBDRplus). PCR in the clinical specimens showed excellent specificity (97.4%) and accuracy (96.8%), good sensitivity (70.4%), but low positive predictive value (40.3%). MGIT-SIRE performed to M. tuberculosis did not confer a reliable result in 16 isolates. Of the remaining 69 isolates, 15 were resistant to streptomycin, seven to isoniazid, seven to ethambutol and five to rifampicin. GenoType MTBDRplus correctly detected isoniazid (seven) and rifampicin-resistant M. tuberculosis strains (five), showing an excellent performance overall (100%). Susceptibility results by the molecular assay applied directly to clinical specimens were identical to those obtained from recovered isolates of the corresponding patients. Combining molecular and conventional methods greatly contribute to early diagnosis and accurate susceptibility testing of tuberculosis.

Impacto orçamentário da incorporação do GeneXpert MTB/RIF para o diagnóstico da tuberculose pulmonar na perspectiva do Sistema Único de Saúde, Brasil, 2013-2017 / Budget impact of the incorporation of GeneXpert MTB/RIF for diagnosis of pulmonary tuberculosis from the perspective of the Brazilian Unified National Health System, Brazil, 2013-2017 / Impacto presupuestario de la incorporación del GeneXpert MTB/RIF para el diagnóstico de la tuberculosis pulmonar desde la perspectiva del Sistema Único de Salud, Brasil, 2013-2017

Resumo: O objetivo do estudo foi estimar o impacto orçamentário do GeneXpert MTB/RIF para o diagnóstico da tuberculose sob a perspectiva do Programa Nacional de Controle da Tuberculose, valendo-se de um modelo estático apoiado no método epidemiológico entre 2013 e 2017. Comparou-se um teste Xpert MTB/RIF com duas baciloscopias diagnósticas. Utilizaram-se dados epidemiológicos, populacionais, de custos, a taxa de câmbio e bases de dados do Sistema Único de Saúde. Foi realizada análise de sensibilidade por cenários. A incorporação do GeneXpert MTB/RIF demandaria um montante de R$ 147 milhões em cinco anos e representaria um impacto de 23% a 26% nos dois primeiros anos, e de cerca de 11% entre 2015 e 2017. Os resultados podem apoiar os gestores brasileiros e dos países latino-americanos no planejamento e gestão na sua decisão de incorporação da tecnologia.

Abstract: The study aimed to estimate the budget impact of GeneXpert MTB/RIF for diagnosis of tuberculosis from the perspective of the Brazilian National Program for Tuberculosis Control, drawing on a static model using the epidemiological method, from 2013 to 2017. GeneXpert MTB/RIF was compared with two diagnostic sputum smear tests. The study used epidemiological, population, and cost data, exchange rates, and databases from the Brazilian Unified National Health System. Sensitivity analysis of scenarios was performed. Incorporation of GeneXpert MTB/RIF would cost BRL 147 million (roughly USD 45 million) in five years and would have an impact of 23 to 26% in the first two years and some 11% between 2015 and 2017. The results can support Brazilian and other Latin American health administrators in planning and managing the decision on incorporating the technology.

Resumen: El objetivo del estudio fue estimar el impacto presupuestario del GeneXpert MTB/RIF para el diagnóstico de la tuberculosis, desde la perspectiva del Programa Nacional de Control de la Tuberculosis de Brasil, valiéndose de un modelo estático, apoyado en el método epidemiológico entre 2013 y 2017. Se comparó un test Xpert MTB/RIF con dos baciloscopias diagnósticas. Se utilizaron datos epidemiológicos, poblacionales, de costes, la tasa de cambio y bases de datos del Sistema Único de Salud. Se realizó un análisis de sensibilidad por escenarios. La incorporación del GeneXpert MTB/RIF demandaría un montante de R$ 147 millones en cinco años y representaría un impacto de 23 a 26% durante los dos primeros años, y de cerca de un 11% entre 2015 y 2017. Los resultados pueden apoyar a los gestores brasileiros y de los países latinoamericanos en la planificación y gestión a la hora de decidir incorporar este tipo de tecnología.

HER 2 status in invasive breast cancer: Immunohistochemistry, fluorescence in-situ hybridization and chromogenic in-situ hybridization.

Introduction : HER2/neu gene status in breast cancers can be evaluated by targeting protein and gene - immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH). Recent studies have shown chromogenic in-situ hybridization (CISH) as a relatively cheaper alternative. Materials and Methods : Forty-three nonconsecutive, randomly selected primary invasive breast cancer cases were evaluated for c-erbB-2 (HER2 protein) by IHC and gene amplification by FISH and CISH. Results of each of the same were compared. Results : CISH showed approximately 90% and 100% concordance for IHC negative and positive cases, respectively; while approximately 94.4% and 91% concordance with FISH amplified and non-amplified cases, respectively. Conclusion : This study showed feasibility of incorporation of CISH as a low cost option in routine management of breast carcinoma in the Indian setting. Secondly, reconfirmation of IHC negative and positive cases can be done by CISH.

Bacterial identification in the diagnostic laboratory: How much is enough.

The major impetus for bacterial identification came after the advent of solid culture media. Morphological appearance of bacterial colonies was often sufficient for their identification in the laboratory. Even in modern times, preliminary identification of most cultivable bacteria is based on such morphological characters. Advances have been made media for the presumptive identifi cation of common organisms encountered in clinical samples. Phenotypic characterisation of bacteria with, physiological tests with a battery of biochemical tests differentiate related bacterial genera as well as confirm their identity. . Each laboratory can select its own method(s) of identification, provided they are based on scientific / epidemiological evidence; clinical laboratory and standards institute (CLSI) is a widely accepted organization and laboratories in many parts of the world follow its recommendations for bacterial identification. Some of the latest advances in identification include Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectroscopy (MALDI-TOF) is a state of art facility used for fast and reliable species-specific identification of bacteria including Mycobacteria and fungi including yeasts. However the single most important factor that decides the method of bacterial identification in any laboratory is the cost involved. In the final analysis, selection of tests for bacterial identification should be based on their standardization with proper scientific basis. Considering the cost and lack of easy availability of commercial kits, we have put forward a simplified and rapid method of identification for most commonly encountered bacterial pathogens causing human infection in India