The use of microbead-based spoligotyping for Mycobacterium tuberculosis complex to evaluate the quality of the conventional method: Providing guidelines for Quality Assurance when working on membranes

Fil: Abadia, Edgar. CNRS Université Paris-Sud 11 Universud. Institute of Genetics and Microbiology UMR8621; Francia.Fil: Zhang, Jian. CNRS Université Paris-Sud 11 Universud. Institute of Genetics and Microbiology UMR8621; Francia.Fil: Ritacco, Viviana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Kremer, Kristin. National Institute for Public Health and the Environment; Paises Bajos.Fil: Ruimy, Raymond. Université Paris- Diderot & Microbiology Laboratory; Francia.Fil: Rigouts, Leen. Prince Leopold Institute of Tropical Medicine. Mycobacteriology Unit; Bélgica.Fil: Gomes, Harrison Magdinier. Oswaldo Cruz Institute. Laboratory of Molecular Biology applied to Mycobacteria; Brasil.Fil: Elias, Atina Ribeiro. Oswaldo Cruz Institute. Laboratory of Molecular Biology applied to Mycobacteria; Brasil.Fil: Fauville-Dufaux, Maryse. Scientific Institute of Public Health. National Reference Centre of Tuberculosis and Mycobacteria; Bélgica.Fil: Stoffels, Karolien. Scientific Institute of Public Health. National Reference Centre of Tuberculosis and Mycobacteria; Bélgica.Fil: Rasolofo-Razanamparany, Voahangy. Institut Pasteur de Madagascar. Unité des Mycobactéries; Madagascar.Fil: Garcia de Viedma, Dario. Hospital Gregorio Marañón. Servicio de Microbiología Clínica y Enfermedades Infecciosas; España.Fil: Herranz, Marta. Hospital Gregorio Marañón. Servicio de Microbiología Clínica y Enfermedades Infecciosas; España.Fil: Al-Hajoj, Sahal. King Faisal Specialist Hospital and Research Center. Department of Comparative Medicine; Arabia Saudita.Fil: Rastogi, Nalin. Institut Pasteur de Guadeloupe. Unité de la Tuberculose et des Mycobactéries - WHO Supranational TB Reference Laboratory; Guadalupe.Fil: Garzelli, Carlo. Università di Pisa. Dipartimento di Patologia Sperimentale Biotecnologie Mediche Infettivologia ed Epidemiologia; Italia.Fil: Tortoli, Enrico. Careggi Hospital. Regional Reference Center for Mycobacteria; ItaliaFil: Suffys, Philip N. Oswaldo Cruz Institute. Laboratory of Molecular Biology applied to Mycobacteria; Brasil.Fil: van Soolingen, Dick. National Institute for Public Health and the Environment; Paises Bajos.Fil: Refregier, Guislaine. CNRS Université Paris-Sud 11 Universud. Institute of Genetics and Microbiology UMR8621; Francia.Fil: Sola, Christophe. CNRS Université Paris-Sud 11 Universud. Institute of Genetics and Microbiology UMR8621; Francia.Background: The classical spoligotyping technique, relying on membrane reverse line-blot hybridization of the spacers of the Mycobacterium tuberculosis CRISPR locus, is used world-wide (598 references in Pubmed on April 8th, 2011). However, until now no inter-laboratory quality control study had been undertaken to validate this technique. We analyzed the quality of membrane-based spoligotyping by comparing it to the recently introduced and highly robust microbead-based spoligotyping. Nine hundred and twenty-seven isolates were analyzed totaling 39,861 data points. Samples were received from 11 international laboratories with a worldwide distribution. Methods: The high-throughput microbead-based Spoligotyping was performed on CTAB and thermolyzate DNA extracted from isolated Mycobacterium tuberculosis complex (MTC) strains coming from the genotyping participating centers. Information regarding how the classical Spoligotyping method was performed by center was available. Genotype discriminatory analyses were carried out by comparing the spoligotypes obtained by both methods. The non parametric U-Mann Whitney homogeneity test and the Spearman rank correlation test were performed to validate the observed results. Results: Seven out of the 11 laboratories (63 %), perfectly typed more than 90% of isolates, 3 scored between 80-90% and a single center was under 80% reaching 51% concordance only. However, this was mainly due to discordance in a single spacer, likely having a non-functional probe on the membrane used. The centers using thermolyzate DNA performed as well as centers using the more extended CTAB extraction procedure. Few centers shared the same problematic spacers and these problematic spacers were scattered over the whole CRISPR locus (Mostly spacers 15, 14, 18, 37, 39, 40). Conclusions: We confirm that classical spoligotyping is a robust method with generally a high reliability in most centers. The applied DNA extraction procedure (CTAB or thermolyzate) did not affect the results in this study. However performance was center-dependent, suggesting that training is a key component in quality assurance of spoligotyping. Overall, no particular spacer yielded a higher degree of deviating results, suggesting that errors

The use of microbead-based spoligotyping for Mycobacterium tuberculosis complex to evaluate the quality of the conventional method: Providing guidelines for Quality Assurance when working on membranes

Contains fulltext : 124321.pdf (publisher's version ) (Open Access)BACKGROUND: The classical spoligotyping technique, relying on membrane reverse line-blot hybridization of the spacers of the Mycobacterium tuberculosis CRISPR locus, is used world-wide (598 references in Pubmed on April 8th, 2011). However, until now no inter-laboratory quality control study had been undertaken to validate this technique. We analyzed the quality of membrane-based spoligotyping by comparing it to the recently introduced and highly robust microbead-based spoligotyping. Nine hundred and twenty-seven isolates were analyzed totaling 39,861 data points. Samples were received from 11 international laboratories with a worldwide distribution. METHODS: The high-throughput microbead-based Spoligotyping was performed on CTAB and thermolyzate DNA extracted from isolated Mycobacterium tuberculosis complex (MTC) strains coming from the genotyping participating centers. Information regarding how the classical Spoligotyping method was performed by center was available. Genotype discriminatory analyses were carried out by comparing the spoligotypes obtained by both methods. The non parametric U-Mann Whitney homogeneity test and the Spearman rank correlation test were performed to validate the observed results. RESULTS: Seven out of the 11 laboratories (63%), perfectly typed more than 90% of isolates, 3 scored between 80-90% and a single center was under 80% reaching 51% concordance only. However, this was mainly due to discordance in a single spacer, likely having a non-functional probe on the membrane used. The centers using thermolyzate DNA performed as well as centers using the more extended CTAB extraction procedure. Few centers shared the same problematic spacers and these problematic spacers were scattered over the whole CRISPR locus (Mostly spacers 15, 14, 18, 37, 39, 40). CONCLUSIONS: We confirm that classical spoligotyping is a robust method with generally a high reliability in most centers. The applied DNA extraction procedure (CTAB or thermolyzate) did not affect the results in this study. However performance was center-dependent, suggesting that training is a key component in quality assurance of spoligotyping. Overall, no particular spacer yielded a higher degree of deviating results, suggesting that errors occur randomly either in the process of re-using membranes, or during the reading of the results and transferring of data from the film to a digital file. Last, the performance of the microbead-based method was excellent as previously shown by Cowan et al. (J. Clin. Microbiol. 2004) and Zhang et al. (J. Med. Microbiol. 2009) and demonstrated the proper detection of spacer 15 that is known to occasionally give weak signals in the classical spoligotyping

Mycobacterium tuberculosis lineage 4 comprises globally distributed and geographically restricted sublineages

Generalist and specialist species differ in the breadth of their ecological niches. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that, whereas the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration.We thank S. Lecher, S. Li and J. Zallet for technical support. Calculations were performed at the sciCORE scientific computing core facility at the University of Basel. This work was supported by the Swiss National Science Foundation (grants 310030_166687 (S.G.) and 320030_153442 (M.E.) and Swiss HIV Cohort Study grant 740 to L.F.), the European Research Council (309540-EVODRTB to S.G.), TB-PAN-NET (FP7-223681 to S.N.), PathoNgenTrace projects (FP7-278864-2 to S.N.), SystemsX.ch (S.G.), the German Center for Infection Research (DZIF; S.N.), the Novartis Foundation (S.G.), the Natural Science Foundation of China (91631301 to Q.G.), and the National Institute of Allergy and Infectious Diseases (5U01-AI069924-05) of the US National Institutes of Health (M.E.)

The emergence of Beijing genotype of <i>Mycobacterium tuberculosis</i> in the Kingdom of Saudi Arabia

Objective : To investigate the prevalence of Beijing genotype strains of Mycobacterium tuberculosis in the Kingdom of Saudi Arabia. Methods : We analyzed the available data on a total of 1505 strains isolated during 2002-2005. Results : Spoligotyping results revealed that Beijing family isolates represented 4.5&#x0025; of all the isolates. Existence of Beijing clade is alarming as this family is known to be multi-drug resistant and transmissible. Conclusions : This study showed that the occurrence of Beijing genotype is associated with young age and drug resistance. The Beijing strains affected both Saudi nationals as well as migrants originating in Asia. The Beijing clade could be responsible for the ongoing transmission of tuberculosis within the community

Mapping the epidemiology and trends of extra-pulmonary tuberculosis in Saudi Arabia

An extra-pulmonary tuberculosis (EPTB) infection rate of 30% in Saudi Arabia remains above the global rate. A variable rate of infection in each province has been reported and the involvement of most organs has been cited. Nationwide collective data on the current trends of infection are scarce and the factors behind the increased rate of EPTB are perplexing. This review endeavors to shed light into the epidemiology of EPTB, various types of infections sites, geographical differences in the infection rate, known risk factors, and challenges in the diagnosis and management of EPTB in Saudi Arabia