BIOCONVERSION OF SECONDARY PRODUCTS OF PROCESSING OF GRAIN CEREALS CROPS

A method has been developed for the production of organic ingredients from secondary products resulting from the high-quality grinding of triticale and wheat into flour, which involves the enzymatic action of amylolytic enzymes to release starch polysaccharides while preserving the native properties of dietary fibers and biologically active substances associated with them. To a large extent, the features of the properties of the obtained ingredients are due to the number and composition of the components of dietary fiber of grain, as well as the morphological features of their structure. It is shown that the viscosity of aqueous colloidal systems at a concentration of soluble dietary fiber of the ingredient 0.5 % increases 11 times; at a concentration of 1.0 %   — 30 times, forming a viscous gel-like structure. This allows them to be used for gelling, thickening and stabilization of aquatic food systems. The use of ingredients with a high content of NLP in baking is possible only taking into account their water absorption capacity. A method for the enzymatic modification of secondary products of processing of grain triticale was developed. On the basis of the study of the kinetics and efficiency of the effect of proteolytic and cellulolytic enzyme preparations (EP) and their compositions, optimal conditions for enzymatic modification (the EP dosage is 0.5…0.75 units of PA/g of bran, 0.3…0.4 units of CA/g of bran, the optimum temperature is 40–50 °С, pH is 5.0 and 3.5, the duration of reactions is 1.5 hours) have been determined. The use of cellulolytic EP allowed to increase the amount of reducing substances and soluble protein by 1.5–2.5 times in comparison with the control sample. The biomodified bran obtained using the MEC «Shearzyme 500 L» + «Neutrase 1.5 MG» and «Viscoferm L» + «Distizym Protacid Extra» has a high degree of hydrolysis of non-starch polysaccharides and proteins, is characterized by a certain ratio of high-, medium-, low-molecular peptides and amino acids, has different functional and technological properties. They can be used in the production of a wide range of general-purpose, functional and treatmentand-prophylactic food products.A method has been developed for the production of organic ingredients from secondary products resulting from the high-quality grinding of triticale and wheat into flour, which involves the enzymatic action of amylolytic enzymes to release starch polysaccharides while preserving the native properties of dietary fibers and biologically active substances associated with them. To a large extent, the features of the properties of the obtained ingredients are due to the number and composition of the components of dietary fiber of grain, as well as the morphological features of their structure. It is shown that the viscosity of aqueous colloidal systems at a concentration of soluble dietary fiber of the ingredient 0.5 % increases 11 times; at a concentration of 1.0 %   — 30 times, forming a viscous gel-like structure. This allows them to be used for gelling, thickening and stabilization of aquatic food systems. The use of ingredients with a high content of NLP in baking is possible only taking into account their water absorption capacity. A method for the enzymatic modification of secondary products of processing of grain triticale was developed. On the basis of the study of the kinetics and efficiency of the effect of proteolytic and cellulolytic enzyme preparations (EP) and their compositions, optimal conditions for enzymatic modification (the EP dosage is 0.5…0.75 units of PA/g of bran, 0.3…0.4 units of CA/g of bran, the optimum temperature is 40–50 °С, pH is 5.0 and 3.5, the duration of reactions is 1.5 hours) have been determined. The use of cellulolytic EP allowed to increase the amount of reducing substances and soluble protein by 1.5–2.5 times in comparison with the control sample. The biomodified bran obtained using the MEC «Shearzyme 500 L» + «Neutrase 1.5 MG» and «Viscoferm L» + «Distizym Protacid Extra» has a high degree of hydrolysis of non-starch polysaccharides and proteins, is characterized by a certain ratio of high-, medium-, low-molecular peptides and amino acids, has different functional and technological properties. They can be used in the production of a wide range of general-purpose, functional and treatmentand-prophylactic food products

TECHNOLOGICAL SCHEMES FOR THE PROCESSES OF PREPARATION AND MILLING BINARY GRAIN MIXTURES AND BIOCHEMICAL EVALUATION OF PRODUCED PRODUCTS

A study of the preparation and milling of a grain mixture containing 7% of flax seeds has been carried out in order to obtain a composite wheat-flax flour, in which the entire biopotential of flax seeds was preserved. It was revealed that the preparation of the components of the grain mixture should be carried out independently, in parallel flows. During the wheat grain preparation the cold conditioning was carried out, the modes of which were the following: humidity — 15.5%, dwell time in the water — 24 hours. The optimal conditions for milling the wheat-flax mixture have been determined, which are the following: yield (%) / ash content (%) in 3 break systems (in terms of the 1st break system — grain) for the first break system — 53.5 / 1.00; for the second break system. — 22.2 / 1.11; totally for the first and the second break systems — 75.7 / 1.035; totally for the first, the second and the third break systems — 81.0 / 1.1. The technological schemes have been developed and the new varieties of wheat-flax flour with predetermined technological properties and increased nutritional value have been formed. The approximate indices of yield and quality of the new wheat-flax flour varieties are the following: Flour A — yield 45–50%, lipids 3.6–4.0%, protein 13–13.5%, ash 0.55–0.70%, whiteness — 50 conventional units; Flour B — yield 20–25%, lipids 5.5–6.0%, protein 14–14.5%, ash 0.9–1.25%, whiteness — 22 conventional units; Flour C — yield 70–75%, lipids 4.5–5.0%, protein 13.6–14.0%, ash 0.75–0.90%, whiteness — 36 conventional units. It was indicated that the total lipids content in flour from two-component mixtures increases by about 4 times, and the total protein content in the studied samples increases by 1–2%. The content of linoleic acid (ɷ‑6) in wheat-flax flour samples is 1.6…3.3 times higher than in wheat flour; the content of linolenic acid (ɷ‑3) in wheat-flax flour samples is 36.8…57.2 times higher than in wheat flour (taking into account the total lipids content in the samples). The enrichment of wheat flour due to flax seeds allows to make up the deficiency of PUFA family in the diet of a modern person and to obtain products on a grain basis of a balanced composition

К вопросу определения гликемического индекса по глюкозе

The analysis of methods for determining the glycemic index (GI) of food products in vivo and in vitro. The authors note that the difference in the methodological approach to the determination of GI in vitro leads to obtaining results that are difficult to compare. A modified method for determining the GI for glucose is proposed, which is based on the method for determining the glycemic index for glucose, which makes it possible to assess the digestibility of various ingredients in products in terms of sugar load, and to calculate the glycemic index for glucose formed in the process of "digestion” of the test product in vitro. The modified technique provides for the use of digestive enzyme preparations: Acedin-pepsin and Panzinorm to provide a deeper "digestion” in vitro, providing a deep degree of hydrolysis of the main macronutrients in in vitro model experiments. The conditions for carrying out enzymatic hydrolysis reactions (temperature, pH, reaction duration) were selected experimentally. The studies carried out to determine the GI in vitro, according to the proposed method, showed comparable values, which indicates the possibility of using this method for the determination of GI in vitro. The results obtained should be considered as indicative, since the authors adhere to the position that the true value of the GI index can only be determined by blood analysis. But in this case, the value of GI is influenced by many factors, including the individual characteristics of the human organism.Проведен анализ методов определения гликемического индекса (ГИ) пищевых продуктов in vivo и in vitro. Авторы отмечают что разница в методическом подходе к определению ГИ in vitro приводит к получению, трудно сопоставимых результатов. Предложена модифицированная методика определения ГИ in vitro в основе которой лежит метод определения гликемического индекса по глюкозе, который позволяет оценить с точки зрения сахарной нагрузки усвояемость в продуктах различных ингредиентов, и рассчитать гликемический индекс по глюкозе, образовавшейся в процессе «переваривания» исследуемого продукта in vitro. Модифицированная методика предусматривает использование для обеспечения более глубокого «переваривания» in vitro пищеварительных ферментных препаратов: Ацедин-пепсин и Панзинорм, обеспечивающих в модельных экспериментах in vitro высокую степень гидролиза основных макронутриентов. Условия проведения реакций ферментативного гидролиза (температура, рН, продолжительность реакции) были подобраны экспериментально. Проведенные исследования по определению ГИ in vitro, согласно предложенной методике показали сопоставимые значения, что свидетельствует о возможности использования данной методики для определения ГИ in vitro. Однако, полученные результаты следует рассматривать как ориентировочные, поскольку авторы придерживаются позиции, что истинное значение показателя ГИ может быть определено лишь по анализу крови, но и в этом случае на значение ГИ влияет множество факторов, в том числе и индивидуальные особенности организма человека.

Отруби из композитной зерносмеси — как объект глубокой переработки. Часть 1. Белково-протеиназный комплекс

Deep processing of grain bran is an important, promising direction that allows the use of by-products (secondary products) of flour milling in order to obtain valuable food components for the creation of enriched food products, as well as specialized grain-based products. Polycomponent bran, obtained during the joint processing of cereals (wheat), legumes (lentils) and oilseeds (flax), in terms of its chemical composition and the state of the proteinproteinase complex, is a unique raw material that can be used for further processing. In particular, it is suitable for the use in producing hydrolysates and other structurally modified products using enzymatic biocatalytic methods. An assessment of the chemical composition and biochemical characteristics of new types of bran showed a high protein content, in which the proportion of the albumin-globulin fraction predominated (78.5-86%), while a significant part of the protein (7.6-10%) was strongly bonded to other biopolymers. The bran proteolytic enzymes acting in the neutral (pH 6.8) and acidic (pH 3.8) pH zones were isolated and studied. It was shown that lentil-flax bran was characterized by the highest proteolytic activity, while the activity of neutral proteinases exceeded the activity of acid proteinases in all three variants: 1.32, 1.37 and 1.56 times, respectively. It was established that protein inhibitors of trypsin and their own proteinases were present in all studied bran types. They inhibited the activity of acid proteinases to a greater extent than neutral ones (% inhibition): 37.5 versus 28.2 (option 1); 32.3 versus 24.5 (option 2); 48.6 versus 32.4 (option 3). The molecular weight, according to gel chromatography, was as follows: neutral proteinases 250,000 200,000 Da, acid proteinases 100,000 75,000 Da. Protein inhibitors isolated from multicomponent bran had a molecular weight of 25,000-20,000 Da. The data obtained will be used in experimental studies on targeted biocatalysis in order to obtain products of a given composition and properties.Глубокая переработка зерновых отрубей — важное, перспективное направление, позволяющее использовать побочные (вторичные) продукты мукомольного производства с целью получения ценных пищевых компонентов для создания обогащенных пищевых продуктов, а также специализированных продуктов на зерновой основе. Поликомпонентные отруби, полученные при совместной переработке зерновых (пшеница), бобовых (чечевица) и масличных (лен) культур, по своему химическому составу и состоянию белковопротеиназного комплекса представляют уникальное сырье, которое можно использовать для дальнейшей переработки. В частности, оно пригодно для применения с целью получения гидролизатов и других структурно-модифицированных продуктов с использованием методов ферментативного биокатализа. Оценка химического состава и биохимических особенностей новых видов отрубей показала высокое содержание белка, в котором преобладает доля альбумино-глобулиновой фракции (78,5-86%), при этом существенная часть белка (7,6-10%) прочно связана с другими биополимерами. Выделены и исследованы протеолитические ферменты отрубей, действующие в нейтральной (рН 6,8) и кислой (рН 3,8) зонах рН. Показано, что чечевично-льняные отруби характеризуются наибольшей протеолитической активностью, при этом активность нейтральных протеиназ превышает активность кислых протеиназ во всех трех вариантах: в 1,32; 1,37 и 1,56 раза соответственно. Установлено, что во всех исследуемых отрубях присутствуют белковые ингибиторы трипсина и собственных протеиназ. Они подавляют активность кислых протеиназ в большей степени, чем нейтральных (% ингибирования): 37,5 против 28,2 (вариант 1); 32,3 против 24,5 (вариант 2); 48,6 против 32,4 (вариант 3). Молекулярная масса, по данным гель-хроматографии, составила: нейтральные протеиназы 250 000 200 000 Да, кислые протеиназы 100 000 75 000 Да. Белковые ингибиторы, выделенные из поликомпонентных отрубей, имели молекулярную массу 25 000 20 000 Да. Полученные данные будут использованы в экспериментальных исследованиях, по направленному биокатализу с целью получения продуктов заданного состава и свойств

Отруби из композитной зерносмеси как объект глубокой переработки. Часть 2. Углеводно-амилазный и липидный комплексы

Polycomponent bran obtained by joint grinding of a grain mixture from cereals (wheat), legumes (lentils) and oilseeds (flax) should be considered as a valuable secondary raw material, the use of which for deep processing will make it possible to obtain various food and feed ingredients. An assessment of the carbohydrate-amylase and lipid complexes of the three variants of multicomponent bran showed that the ratio of amylose and amylopectin in the starch of three-component bran is almost the same, however, in lentil-flax bran, the proportion of amylose is 1.6 times higher than in the first two variants. The specific activity of amylases in three-component bran is about 2 times higher than in lentil-flax bran. In addition, the latter are characterized by a higher content of reducing sugars and fiber. The molecular weight of amylases isolated from three-component bran, according to gel chromatography, was: α-amylase — 40,000 Da; β-amylase — 60,000 Da. It has been established that the addition of flax seeds to the grinding mixture significantly increases the fat content in bran 6.4; 6.0 and 12.9%. The fatty acid composition of the studied bristles is characterized by the predominance of unsaturated fatty acids. At the same time, the ratio of essential acids — linoleic acid (ɷ‑6) to α-linolenic acid (ɷ‑3) in favor of the most deficient α-linolenic acid — was typical for lentil-flax bran and amounted to 1:4.2. The activity of alkaline lipases, which exhibit their effect at pH 8.0 (mainly cereal lipases), and acid lipases (mainly oilseed lipases) with an optimum of action at pH 4.7 in three-component bran samples are approximately the same, and lentil-flax bran is characterized by a high specific acid lipase activity, which is approximately 4.2 times higher than the activity of acid lipases of three-component bran. The data obtained, along with data on the characteristics of the protein-proteinase complex of the studied types of bran, will be used in the development of methods for enzymatic modification (deep processing) and in the preparation of components for the creation of new food products with increased nutritional and biological value.Поликомпонентные отруби, полученные при совместном размоле зерносмеси из зерновых (пшеница), бобовых (чечевица) и масличных (лен) культур, следует рассматривать как ценное вторичное сырье, использование которого для глубокой переработки позволит получать различные пищевые и кормовые ингредиенты. Оценка углеводно-амилазного и липидного комплексов трех вариантов поликомпонентных отрубей показала, что соотношение амилозы и амилопектина в крахмале трехкомпонентных отрубей практически одинаково, однако в чечевично-льняных отрубях доля амилозы в 1,6 раза выше, чем в первых двух вариантах. Удельная активность амилаз трехкомпонентных отрубей примерно в 2 раза выше, чем в чечевично-льняных отрубях. Кроме того, последние характеризуются более высоким содержанием восстанавливающих сахаров и клетчатки. Молекулярная масса амилаз, выделенных из трехкомпонентных отрубей, по данным гель-хроматографии составила: α-амилаза — 40 000 Да; β-амилаза — 60 000 Да. Установлено, что добавление семян льна в помольную смесь значительно увеличивает содержание жира в отрубях 6,4; 6,0 и 12,9%. Жирнокислотный состав исследуемых отрубей характеризуется преобладанием ненасыщенных жирных кислот. При этом соотношение эссенциальных кислот — линолевой кислоты (ɷ-6) к α-линоленовой кислоте (ɷ-3) в пользу наиболее дефицитной α-линоленовой кислоты — было характерно для чечевично-льняных отрубей и составило 1:4,2. Активность щелочных липаз, проявляющих свое действие при рН 8,0 (преимущественно зерновые липазы), и кислых липаз (преимущественно липазы масличных культур) с оптимумом действия при рН 4,7 в образцах трехкомпонентных отрубей примерно одинаковая, а чечевично-льняные отруби характеризуются высокой удельной активностью кислой липазы, которая примерно в 4,2 раза превосходит активность кислых липаз трехкомпонентных отрубей. Полученные данные, наряду с данными по особенностям белково-протеиназного комплекса исследуемых видов отрубей, будут использованы при разработке способов ферментативной модификации (глубокая переработка) и при получении компонентов для создания новых пищевых продуктов с повышенной пищевой и биологической ценностью

Белково-жировой концентрат для обогащения пшеничной муки.

Wheat flour, especially high grade flour, is significantly impoverished in macro-, micronutrients and other valuable components such as essential amino acids, essential fatty acids, vitamins, minerals, soluble and insoluble dietary fibers. To enrich wheat flour, the authors produced lentil-flax flour (protein-fat concentrate) with the high protein (27.5%) and fat (11.9%) content. The developed technological scheme of the combined grinding of lentil (67%) and flax (33%) seeds included the I–III break systems, sizing system, scratch system, 1–3 reduction systems. When studying physico-chemical and biochemical indicators, it was found that the protein-fat concentrate was close to the corresponding indicators of wheat flour by mechanical characteristics. A significant proportion of the albumin-globulin fraction of soluble proteins (88%), as well as the high content of the most deficient essential α-linolenic acid (6.11% compared to 0.05% in wheat flour with regard to the total fat content) suggest the high nutritional and biological value of the obtained product. Evaluation of an effect of the protein-fat concentrate on the indicators of the finished products (crackers) showed that its introduction in an amount of 15% of the total flour volume not only did not worsen but even improved sensory indices by several criteria. The high total sensory score (32 points) indicates the standard quality of the obtained product. Addition of lentil-flax flour in an amount of 15% of total flour weight in production of bakery products as well as bakery confectionary products will allow extending the assortment of balanced farinaceous products, significantly reducing the deficiency of essential α-linolenic acid in diets upon their consumption according to the physiological norms.Пшеничная мука, особенно мука высших сортов, значительно обеднена макро-, микронутриентами и такими ценными компонентами, как незаменимые аминокислоты, эссенциальные жирные кислоты, витамины, минеральные вещества, растворимые и  нерастворимые пищевые волокна. С  целью обогащения пшеничной муки была получена чечевично-льняная мука (белково-жировой концентрат) с высоким содержанием белка (27,5%) и жира (11,9%). Разработанная технологическая схема совместного размола семян чечевицы (67%) и льна (33%) включала I–III драные системы, шлифовочную систему, вымольную систему, 1–3 размольные системы. При исследовании физико-химических, биохимических показателей установлено, что по механическим характеристикам белково-жировой концентрат был близок к соответствующим показателям пшеничной муки. Значительная доля альбумино-глобулиновой фракции растворимых белков (88%), а также высокое содержание наиболее дефицитной эссенциальной α-линоленовой кислоты (6,11% против 0,05% в пшеничной муке с учетом общего содержания жира) свидетельствуют о высокой пищевой и биологической ценности полученного продукта. Оценка влияния белково-жирового концентрата на показатели готовых изделий (крекеры) показала, что его внесение в количестве 15% от общего объема муки не только не ухудшает, а по некоторым критериям даже улучшает органолептические показатели. Высокая суммарная органолептическая оценка (32 балла) свидетельствует о стандартном качестве полученного продукта. Добавление 15% чечевично-льняной муки от общей массы муки при производстве хлебобулочных и мучных кондитерских изделий позволит расширить ассортимент сбалансированных мучных изделий, существенно сократить дефицит эссенциальной α-линоленовой кислоты в рационе питания при их потреблении в соответствии с физиологическими нормами

Angstrom-Scale Distance Dependence of Antenna-Enhanced Vibrational Signals

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Characterization of the genetic diversity of Mycobacterium tuberculosis in São Paulo city, Brazil

<p>Abstract</p> <p>Background</p> <p>Tuberculosis is a major health problem in São Paulo, Brazil, which is the most populous and one of the most cosmopolitan cities in South America. To characterize the genetic diversity of <it>Mycobacterium tuberculosis </it>in the population of this city, the genotyping techniques of spoligotyping and MIRU were applied to 93 isolates collected in two consecutive years from 93 different tuberculosis patients residing in São Paulo city and attending the Clemente Ferreira Institute (the reference clinic for the treatment of tuberculosis).</p> <p>Findings</p> <p>Spoligotyping generated 53 different spoligotype patterns. Fifty-one isolates (54.8%) were grouped into 13 spoligotyping clusters. Seventy- two strains (77.4%) showed spoligotypes described in the international databases (SpolDB4, SITVIT), and 21 (22.6%) showed unidentified patterns. The most frequent spoligotype families were Latin American Mediterranean (LAM) (26 isolates), followed by the T family (24 isolates) and Haarlem (H) (11 isolates), which together accounted for 65.4% of all the isolates. These three families represent the major genotypes found in Africa, Central America, South America and Europe. Six Spoligo-International-types (designated SITs by the database) comprised 51.8% (37/72) of all the identified spoligotypes (SIT53, SIT50, SIT42, SIT60, SIT17 and SIT1). Other SITs found in this study indicated the great genetic diversity of <it>M. tuberculosis</it>, reflecting the remarkable ethnic diversity of São Paulo city inhabitants. The MIRU technique was more discriminatory and did not identify any genetic clusters with 100% similarity among the 93 isolates. The allelic analysis showed that MIRU loci 26, 40, 23 and 10 were the most discriminatory. When MIRU and spoligotyping techniques were combined, all isolates grouped in the 13 spoligotyping clusters were separated.</p> <p>Conclusions</p> <p>Our data indicated the genomic stability of over 50% of spoligotypes identified in São Paulo and the great genetic diversity of <it>M. tuberculosis </it>isolates in the remaining SITs, reflecting the large ethnic mix of the São Paulo city inhabitants. The results also indicated that in this city, <it>M. tuberculosis </it>isolates acquired drug resistance independently of genotype and that resistance was more dependent on the selective pressure of treatment failure and the environmental circumstances of patients.</p

Mapping the Complex Morphology of Cell Interactions with Nanowire Substrates Using FIB-SEM

Using high resolution focused ion beam scanning electron microscopy (FIB-SEM) we study the details of cell-nanostructure interactions using serial block face imaging. 3T3 Fibroblast cellular monolayers are cultured on flat glass as a control surface and on two types of nanostructured scaffold substrates made from silicon black (Nanograss) with low- and high nanowire density. After culturing for 72 hours the cells were fixed, heavy metal stained, embedded in resin, and processed with FIB-SEM block face imaging without removing the substrate. The sample preparation procedure, image acquisition and image post-processing were specifically optimised for cellular monolayers cultured on nanostructured substrates. Cells display a wide range of interactions with the nanostructures depending on the surface morphology, but also greatly varying from one cell to another on the same substrate, illustrating a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map. The results demonstrate that detailed nanoscale resolution images are required to begin understanding the wide variety of individual cells' interactions with a structured substrate. The map will provide a framework for light microscopy studies of such interactions indicating what modes of interactions must be considered

Mycobacterium tuberculosis ecology in Venezuela: epidemiologic correlates of common spoligotypes and a large clonal cluster defined by MIRU-VNTR-24

<p>Abstract</p> <p>Background</p> <p>Tuberculosis remains an endemic public health problem, but the ecology of the TB strains prevalent, and their transmission, can vary by country and by region. We sought to investigate the prevalence of <it>Mycobacterium tuberculosis </it>strains in different regions of Venezuela. A previous study identified the most prevalent strains in Venezuela but did not show geographical distribution nor identify clonal genotypes. To better understand local strain ecology, we used spoligotyping to analyze 1298 <it>M. tuberculosis </it>strains isolated in Venezuela from 1997 to 2006, predominantly from two large urban centers and two geographically distinct indigenous areas, and then studied a subgroup with MIRU-VNTR 24 loci.</p> <p>Results</p> <p>The distribution of spoligotype families is similar to that previously reported for Venezuela and other South American countries: LAM 53%, T 10%, Haarlem 5%, S 1.9%, X 1.2%, Beijing 0.4%, and EAI 0.2%. The six most common shared types (SIT's 17, 93, 605, 42, 53, 20) accounted for 49% of the isolates and were the most common in almost all regions, but only a minority were clustered by MIRU-VNTR 24. One exception was the third most frequent overall, SIT 605, which is the most common spoligotype in the state of Carabobo but infrequent in other regions. MIRU-VNTR homogeneity suggests it is a clonal group of strains and was named the "Carabobo" genotype. Epidemiologic comparisons showed that patients with SIT 17 were younger and more likely to have had specimens positive for Acid Fast Bacilli on microscopy, and patients with SIT 53 were older and more commonly smear negative. Female TB patients tended to be younger than male patients. Patients from the high incidence, indigenous population in Delta Amacuro state were younger and had a nearly equal male:female distribution.</p> <p>Conclusion</p> <p>Six SIT's cause nearly half of the cases of tuberculosis in Venezuela and dominate in nearly all regions. Strains with SIT 17, the most common pattern overall may be more actively transmitted and SIT 53 strains may be less virulent and associated with reactivation of past infections in older patients. In contrast to other common spoligotypes, strains with SIT 605 form a clonal group centered in the state of Carabobo.</p