Literature highlights the effects of mycolic acid (MA) fine-structure on biological activity, pathogenicity, virulence and cell wall structure and permeability. Knowledge on MA-structure and how their conformations are dependent on their precise molecular composition becomes essential in exploiting these properties in drug-design and in advancing our understanding of the disease. In our group evidence for a structural or functional relationship between cholesterol and MAs have been discovered. The aim of the experimental part of this work was to study this relationship further by attempting to quantify the interaction between cholesterol and MAs in liposomes on an evanescent field biosensor. The binding profiles that were obtained could not be evaluated with kinetic software and the interaction between cholesterol and MAs was not linearly dependant on the concentration of cholesterol. However, novel insight into the interaction was gained when it was observed that cholesterol only accumulated on MA liposomes when cholesterol liposomes containing concentrations of cholesterol resulting in a suspected liquid ordered phase, were used. This is significant since it implies that cholesterol in membrane rafts of the host cell that exist in a liquid ordered phase would be able to interact with MAs under physiological conditions. The theoretical part of this work represents the first molecular modeling study in which MAs are allowed to fold with no conformational restrictions. It is proposed that MAs fold as a function of their functional groups, stereochemistry, and various chain lengths. It was also investigated whether methylation of the acid group changes conformational preferences. The effect of chain length on cyclopropane structure and the viability of systematic conformational searching in MAs were shown using quantum mechanics. Replicate molecular dynamics simulations were done for 4 ns in vacuo on alpha-; methoxy-; methoxy methyl ester- and keto-MAs. MAs had an open starting conformation without conformational restrictions. Results were analysed using eight distances characteristic of the conformational fold. Using these distances, W-, U- and Z-shaped folds were identified. Principal component analysis (PCA) and self-organising maps (SOMs) were used to evaluate differences and trends in MA-conformations. Quantum chemical results showed that chain length did not affect cyclopropane structure and that the systematic plotting of potential energy surfaces is an effective tool to analyse effects of changes in geometry on the energy of the molecule and to predict favoured conformations. Remarkably, single MAs assumed W-, U- and Z-folds in vacuo during molecular dynamics simulations that have previously been observed in monolayers. PCA and SOM plots showed that keto-MA folded faster than other MAs. Alpha-MA showed the highest frequency of W-, U- and Z-folds. Methoxy-MA did not readily fold at its cis-cyclopropane group. Methylation of the acid group of methoxy-MA did not show remarkable differences in the conformations assumed, but almost doubled the frequency of WUZ-structures obtained as compared to non-esterified methoxy-MA. The inherent structural differences between MA-subclasses clearly affect the trends in structural folds that they assume. Molecular modeling of MAs proved to be a versatile tool for resolving structure-function relationships at the molecular level. Copyright 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Prinsloo, W 2008, Computational models for conformations of cell wall mycolates from Mycobacterium tuberculosis, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-06122009-114802 / > E1400/gm / Dissertation (MSc)--University of Pretoria, 2009. / Biochemistry / unrestricted

The immunological effects of mycolic acids (MA) from Mycobacterium tuberculosis on mouse peritoneal macrophages were studied. MA was solubilbized using various carriers. Phagosome uptake and maturation (into late stage phagolysosomes) were compared using fluorescent markers and the confocal microscope. During assessment on the effects of MA on mouse macrophages, changes in morphology and activation of the macrophages were found. This indicated that the MA was immune reactive towards macrophages. The phenotype of cell that develops after in vivo loading with MA was characterized by using cell surface markers: it was found that MA-Ioaded macrophages developed into foam cells. Cell survival, proliferation and macrophage cytokine production were examined to characterize the foam-like cells. The effect of MA-induced foam-like cells on living Mycobacterium tuberculosis was evaluated and increased bactericidal activity was found. The roles of reactive oxygen and nitrogen intermediates via myeloperoxidase were also examined and a theoretical mechanism for the formation of foam cells proposed. The possible role of myeloperoxidase in activation of macrophages, foam cell formation and killing of Mycobacterium tuberculosis is discussed. It is postulated that a possible relationship might exist between tuberculosis and atherosclerosis that is facilitated by mycolic acids. / Thesis (DPhil (Human Physiology))--University of Pretoria, 2005. / Physiology / unrestricted

Tuberculosis (TB) is a collective name for the bacterial infection, which is caused by members of the Mycobacterium tuberculosis (M. tb) complex and can infect the lungs (pulmonary) as well as the kidneys, lymph nodes, bones and joints (extra-pulmonary). The re-emergence of drug-resistant strains and the HIV epidemic are among the main reasons for the resurgence of TB and there is a need for new drugs and diagnostic assays which are rapid and sensitive. Serodiagnostic assays have the potential of being rapid, inexpensive and relatively non-invasive. The most abundant antigen in the cell wall of M. tb, which has been analysed with ELISA and resonant mirror biosensor assays for use in serodiagnosis, is mycolic acid (MA). The sensitivity previously obtained in the ELISA assay was however inadequate for serodiagnostic purposes. It was believed that MA mimicked the structure of cholesterol, thereby causing anti-cholesterol human antibodies from TB negative sera to bind to MA and result in a large number of false positives. Within this work the apparent molecular mimicry between MA and cholesterol was investigated using a competitive enzyme linked inhibition assay (CELIA) assay. The results suggested that MA in liposomes resembled the liquid ordered arrangement of cholesterol in liposomes, rather than a direct mimicry of individual molecules. The nature of the antibody from TB negative patient sera binding to MA coated onto ELISA plates was also investigated. The results obtained from this study have not disproved the hypothesis of a cross-reactive anti-cholesterol antibody, but it would appear that the MA signal from TB negative serum was partially due to the binding of anti-MA antibodies. The presence of anti-MA antibodies in TB negative serum could have been the result of prior BCG vaccination, latent infection or due to constant immune stimulation from saprophytic mycobacteria. This creates the potential of using antibodies to MA to distinguish between latent TB infection and active disease. Furthermore, in order to overcome the low sensitivity of the ELISA assay due to high background signals from TB negative serum, members of our group previously developed a resonant mirror biosensor inhibition assay based on MA contained in liposomes. The biosensor measured mass accumulation and the identity of the binding molecules were unknown. It was shown here that one of the serum components binding to the immobilised MA liposomes in the biosensor inhibition assay was immunoglobulin G antibodies. The specificity of both the ELISA and biosensor assays previously analysed using a natural mixture of MA however, remained poor, and in the search for a more specific antigen, this study investigated the potential of MA subclasses for TB serodiagnosis using ELISA. It was observed that the antibody binding signal to the MA subclasses depended on the polarity of the coating solution, for which hexane was the preferred solvent. Both the alpha- and keto-MA subclasses could better distinguish between a range of TB positive patient and TB negative sera compared with the natural mixture of MA. These results suggested that a particular subclass applied in the biosensor inhibition assay could enhance the test to reach the required sensitivity and specificity required for the serodiagnosis TB. / Dissertation (MSc)--University of Pretoria, 2011. / Biochemistry / unrestricted

Master of Science in Biomedical Sciences / Department of Diagnostic Medicine/Pathobiology / Jodi L. McGill / The causative agent of tuberculosis (TB) in cattle is Mycobacterium bovis (M. bovis). γδ T cells are a unique subset of nonconventional T cells that play major roles in both the innate and adaptive arms of the immune system. Bovine γδ T cells have the capacity for multiple immune functions during infection with M. bovis. However, the alternative functions of γδ T cells as well as the responses of γδ T cells in vivo at the site of infection remain unclear. To identify novel functions for γδ T cells in response to M. bovis infections, RNA sequencing and transcriptomics analysis was completed on peripheral blood γδ T cells isolated from virulent M. bovis-infected cattle. Differentially expressed genes were confirmed with real-time PCR. In an attempt to model in vivo cell-to-cell interactions at the site of infection, γδ T cells were also isolated from naïve and M. bovis-infected calves and co-cultured with autologous, BCG-infected, monocyte-derived macrophages. γδ T cell chemokine and cytokine expression was analyzed via ELISA and real-time PCR. The characteristic lesions of bovine tuberculosis are well-organized pulmonary granulomas. To determine the relevance of the RNA-sequencing and in vitro co-culture results to in vivo infection, tissue samples from granulomatous lesions in the lungs and mediastinal lymph nodes of virulent M. bovis-infected cattle were collected 3 months after infection. mRNA transcripts for γδ T cells expression of-- IFN-γ, IL-17, IL-10, IL-22, and CCL2 were microscopically evaluated within the granulomas using an in situ hybridization system, RNAScope (Advanced Cell Diagnostics Inc.). Co-culture experiments and transcriptomics analysis revealed increased expression of chemokines and various cytokines by γδ T cells responding to M. bovis infection. The novel in situ hybridization assay revealed that cytokine expression by γδ T cells varied within the lesions, with significant levels of CCL2 and IFN-γ, and low expression of IL-10, IL-22, and IL-17 in situ at this time-point after infection. Co-culture experiments also revealed that γδ T cells from virulent M. bovis-infected cattle have the capacity to directly impact the viability of M. bovis in vitro. Our results suggest that γδ T cells accumulate within the granulomas, and influence host immunity to M. bovis by secretion of cytokines and chemokines, and direct cytotoxicity, in response to infected macrophages.

Objective This study investigated an outbreak of Bartonellosis in a coastal region in Peru. Results A total of 70 (n = 70) samples with clinical criteria for the acute phase of Bartonellosis and a positive peripheral blood smear were included. 22.85% (n = 16) cases of the samples were positive for Bartonella bacilliformis by PCR and automatic sequencing. Of those positive samples, 62.5% (n = 10) cases were positive only for B. bacilliformis and 37.5% (n = 6) cases were positive to both Mycobacterium spp. and B. bacilliformis. The symptom frequencies were similar in patients diagnosed with Carrion’s disease and those co-infected with Mycobacterium spp. The most common symptoms were headaches, followed by malaise and arthralgia.

Tuberculosis (TB) is a disease that the World Health Organisation (WHO) regards as a global pandemic. There is a great need for new drugs to combat this threat. Drug resistant strains of the causative agent, Mycobacterium tuberculosis (Mtb), have increased the urgency of this quest for novel anti-mycobacterial medicines. Publication of the Mtb genome sequence revealed a large number of cytochrome P450 (CYP) enzymes [Cole, S. T. et al. 1998]. These mono-oxygenase enzymes have been studied for many years and are responsible for metabolic functions in every kingdom of life. Research on the Mtb P450s to date has highlighted several of them as having critcal roles within the organism. CYP121 and CYP128 have been implicated as essential through gene knockout studies. It has been demonstrated that CYP125 is not essential for viability. However, it is part of a gene cluster highly important for Mtb infectivity and virulence. Due to the prospective importance of P450s to Mtb, this group of enzymes is under investigation as a source of novel drug targets. CYP142 was discovered as a potential drug target after it was located to a gene cluster involved in cholesterol catabolism during Mtb dormancy. As part of this PhD project, it was demonstrated that CYP142 performs an almost identical role to that reported for CYP125. These enzymes both perform C27 hydroxylation and carboxylation of the cholesterol side chain. However, variations in the level of oxidation have been identified, dependent upon the redox system with which these P450s are associated. A crystal structure of CYP142 showing high similarity in active site architecture to CYP125 supports the physiological role of CYP142 in cholesterol catabolism. Combining this with in vitro data which demonstrates that CYP142 possesses high affinity for a range of azole anti-fungal agents [Ahmad, Z. et al. 2005, 2006] supports the suggestion that it is a candidate target for the next generation of anti-mycobacterial drugs. CYP144 was highlighted as being important during the latent phase of Mtb growth, a phase that is not targeted by any of the current antimycobacterials. Work performed as part of this PhD has shown that many characteristics of CYP144 are highly comparable to those reported for other MtbP450s. CYP144 shows high affinity and specificity towards many azole molecules. Econazole, clotrimazole and miconazole have repeatedly been shown to bind to MtbP450s, including CYP144 and CYP142, with high affinity and are excellent potential candidates as novel anti-mycobacterial agents. An N-terminally truncated form of CYP144, CYP144-T, has been investigated in the pursuit of a CYP144 crystal structure. It is hoped that this will enable the elucidation of a physiological role for CYP144. Both CYP142 and CYP144 have demonstrated biochemical and biophysical characteristics that contribute to our knowledge of P450 enzymes. This PhD has established that CYP142 exhibits an equilibrium between P450 and P420 species in its CO-bound, ferrous form. A conversion from P420, and stabilisation of P450, upon substrate binding was also demonstrated. CYP144 displays unusual azole coordination characteristics when examined by EPR and removal of the CYP144 gene from Mtb increased sensitivity of the strain to clotrimazole. Studies of these enzymes has advanced knowledge of P450 and Mtb redox chemistry, established roles for the MtbP450 cohort and identified the potential of anti-mycobacterial drugs and associated targets.

Tuberculosis has become one of the world’s most devastating diseases, with more than two million deaths and eight million new cases occurring annually due to the development of drug-resistant strains of Mycobacterium tuberculosis, the breakdown of the immune system of its host by HIV, lapses in public health programmes and the fact that diagnosis of TB is not 100% reliable. Early, affordable, unsophisticated and accurate diagnosis of TB to facilitate timely and proper treatment has become of highest priority to public health. Mycolic acid (MA) is the major lipid cell wall component of Mycobacterium tuberculosis and is unique to mycobacteria and closely aligned genera. Mycolic acids have been shown to be unique antigens for TB diagnosis and have been utilized in standard serodiagnostic techniques, but sensitivity and specificity was found to be unsatisfactory. Two vastly different techniques were investigated in this study – one making use of antibodies and MA, the other, just MA and its unique physical properties of interaction with other MA using fluorescently labelled MA. In the first approach, Sepharose protein-A was employed to trap patient IgG antibodies. The anti-MA antibodies were then quantified by probing with liposomes containing fluorescently labelled MA. Although it generally worked well, a few false –positive and –negative results were obtained. This assay appeared to be more accurate than the standard ELISA immunoassay but it is more labour intensive and not even remotely as amenable to large-scale screening and automation as ELISA. The second approach is based on the release of fluorescent MA from immobilized liposomes on glass by means of the specific attraction that MA in test liposomes or TB patient serum was perceived to have on the immobilized MA. The end-point measured was the remaining fluorescent MA on the surface. Differences were observed between the control and patients’ sera at a very high dilution but not between the HIV negative, TB positive and HIV positive, TB positive patients. This was merely an exploratory investigation and more work still needs to be done before the test is ready for validation with large numbers of serum samples. If subsequent studies confirm these findings, then this concept may be converted into a simple, rapid and affordable TB diagnostic test or be used in combination with the IAsys affinity biosensor to provide a more thorough diagnosis / Dissertation (MSc (Biochemistry))--University of Pretoria, 2009. / Biochemistry / unrestricted

Em todo o mundo, menos de 5% dos doentes com tuberculose (TB), sejam casos novos ou previamente tratados, tem a avaliação dos isolados quanto ao perfil de sensibilidade aos antibioticos. No Rio Grande do Sul, estado localizado no sul do Brasil, cerca de 4700 casos novos de TB são registrados a cada ano, com uma taxa de cura de 68,9%, e uma taxa de abandono de 7,5%. A identificação rápida da resistência às drogas, em isolados clínicos de M. tuberculosis é importante para o estabelecimento de uma quimioterapia eficaz bem como para evitar a propagação de cepas resistentes. Os objetivos deste estudo foram caracterizar os pacientes de TB com maior risco de possuir TB-­‐MDR, analisando o perfil de resistência às drogas dos isolados e o perfil epidemiológico desses pacientes. Além disso utilizou-­‐se as amostras clínicas para avaliar o teste comercial (GenoType® MTBDRplus) e para desenvolver e padronizar um novo teste (Detect-­‐TBMR) para detectar as mutações mais frequentes associadas a resistência à INH e RIF. Uma proporção significativamente maior (75% versus 20%, p = 0,009) de pacientes do gênero masculino foi encontrada entre os casos resistentes às drogas do que entre os casos suscetíveis. 43,8% dos pacientes demoraram mais de 30 dias para procurar assistência médica e no grupo TB MDR, 25% dos casos não tinha sido submetido a qualquer tratamento prévio anti-­‐TB. Em nossas amostras, encontramos uma proporção de 48,3% de TB-­‐ MDR. A família T foi a família de spoligotipo mais frequente. Comparado com o método da proporções, a sensibilidade e especificidade do ensaio MTBDRplus foram 82% e 94% para a resistência à RIF, 60% e 94% para resistência à INH. Comparado com sequenciamento, a sensibilidade e especificidade do ensaio MTBDRplus foi 92% e 97% para a resistência à RIF e 100% e 100% para a resistência à INH, respectivamente. Para detectar resistência à RIF e INH, o ensaio Detect-­‐TBMDR mostrou sensibilidade e especificidade de 79,3% e 77,0% e 100% e 65%, respectivamente, em comparação com o método da proporções. Comparado com o sequenciamento, a sensibilidade e especificidade do ensaio Detect-­‐TBMDR foi de 81,2% e 94,7% e 100% e 96,2%, para detectar e resistência à RIF e INH, respectivamente. Ainda existem discordâncias entre o método das proporções e a abordagem molecular, particularmente em relação a resistência à INH. Contudo, estes métodos são muito importantes para o manejo mais rápido e correto dos pacientes, auxiliando na escolha do melhor esquema terapêutico. / In most parts of the world, less than 5% of new and previously treated tuberculosis (TB) patients are tested for multidrug resistance (MDR) TB. In Rio Grande do Sul state, the southern most Brazilian state; approximately 4700 new cases of TB are recorded each year, with a cure rate of 68.9%, and a noncompliance rate of 7.5%. Rapid identification of drug resistance in clinical isolates of Mycobacterium tuberculosis is important to facilitate rapid and adequate chemotherapy of TB, and to prevent the spread of resistant strains. The aim of this study was to characterize TB patients at higher risk of having MDR-TB, to analyze the drug resistance and epidemiological profile of these patients. Use the clinical samples to assess the commercial test (GenoType® MTBDRplus) and develop and standardize a new test (Detect-MDRTB) for detecting the most frequent mutations associated with resistance to INH and RIF. A significantly higher proportion (75% versus 20%, p = 0.009) of males were found among drug-resistant cases than drug susceptible cases. 43.8% of patients took longer than 30 days to seek medical care and in the MDR group 25% of the cases did not undergo any previous anti-TB treatment. In our samples we found a proportion of 48.3% of MDR-TB. The T family was the most frequent spoligotype family. Compared with the proportion method, the sensitivity and specificity of the MTBDRplus assay were 82% and 94% for RIF-resistance, 60% and 94% for INH resistance. Compared with sequencing, the sensitivity and specificity of the MTBDRplus assay were 92% and 97% for RIF-resistance, 100% and 100% for INHresistance. To detect RIF and INH-resistance, the Detect-TBMDR assay showed a sensitivity and specificity of 79.3% and 77.0%, and 100% and 65%, respectively, compared to proportion method. When compared with sequencing, Detect-TBMDR assay, to detect RIF and INH-resistance, showed a sensitivity and specificity of 81.2% and 94.7% and to 100% and 96.2%, respectively. Discordances still exist between the proportion method and molecular approach, particularly regarding INH-resistance. However, these methods are very important for the management faster and correct patient, helping to choose the best treatment regimen.

[EN] In the last years, various genotyping techniques were developed for isolation of Mycobacterium tuberculosis complex (MTBC) that has demonstrated a high discriminatory power. In this study, after the identification of selected strains at level of species by Genotype MTBC technique, we evaluated the profit of the simplified amplified-fragment Length Polymorphism technique (AFLPs) and the Mycobacterial Interspersed Repetitive Units technique (MIRU-15). A total of 131 mycobacterium tuberculosis isolates were analyzed, 68 isolates were collected in Ecuador, from the Clinical Laboratory of Hospital Alli Causai located in city of Ambato, and the Laboratory of Bacteriology in Carlos Andrade Marín Hospital located in the capital city Quito. The remaining 63 isolates were harvested in Spain and belong to microorganism's collection of Microbiology Services of Consorcio Hospital General Universitario and Hospital Clínico Universitario of the city of Valencia. Among these isolates, 126 were identified by conventional methods such as molecular MTBC, corresponding to 106 patients. The Mycobacterium tuberculosis control strain ATCC 25177 was also identified as such by this method. The AFLPs technique allowed as to group the strains in twelve patterns (P1 to P8, P10, P12, P13, P14), of which the most prevalent were patterns P1 with 77 (61.1%) and P2 with 27 (21, 4%) isolates, representing 82.5% of the same. These were followed by the pattern P5 with 5 (3.9%) isolates, the patterns P3, P4 and P6 grouped 3 isolates each one (2.4%), the patterns P8 and P12 with 2 isolates (1.6% ) and finally the patterns P7, P10, P13 and P14 with 1 isolated each one (0.8%). The control strain M. tuberculosis ATCC 25177, showed a restriction profile that prevented their inclusion in any of the patterns described. The discriminatory power of the Hunter-Gaston discriminatory index (HGDI) method was 0.5812 against to 0.9843 of the MIRU-15 technique, which grouped 69 strains (54.8%) in 20 clonal complex and 57 unique patterns (45.2%). In the case of Spain, the strains were related mostly to the lineage 4 or Euro-American including: Cammeroon (1.59%), Haarlem (36.51%), S (31.75%), and LAM (19.05%); the lineage 6 or West Africa I (9.53%), the lineage 1 or EIA (1.59%) In the case of Ecuador the strains were related to the lineage 4: Haarlem (42.86%), S (33.33%) and LAM (22.22%) and Beijing lineage 2 (1.59%) from Asia. The MIRU-VNTR Variable-Number Tandem Repeats (15 loci) technique proved to be a stable system, reproducible and high discriminatory power in comparison with AFLPs system, allowing the use of it to conduct prospective population studies with the aim of contributing to the public health programs to control Tuberculosis (TB). / [ES] En los últimos años se han desarrollado diversas técnicas de genotipificación para aislados de Mycobacterium tuberculosis complex (MTBC) que han demostrado tener un alto poder discriminatorio. En este estudio, tras identificación de las cepas seleccionadas al nivel de especie mediante la técnica comercial GenoType MTBC, se ha evaluado la utilidad de la técnica simplificada del Polimorfismo de Longitud de Fragmentos Amplificados (AFLPs) y la técnica de Unidades Repetitivas Intercaladas Micobacterianas (MIRU-15). Se analizaron un total de 131 aislados clínicos de los cuales 68 aislados fueron recolectados en Ecuador, provenientes tanto del Laboratorio Clínico del Hospital Alli Causai ubicado en la ciudad de Ambato, provincia de Tungurahua como del Laboratorio de Bacteriología del Hospital Carlos Andrade Marín ubicado en la ciudad capital Quito, provincia de Pichincha. Los 63 aislados restantes fueron recolectados en España y pertenecían colección de microorganismos de los Servicios de Microbiología del Consorcio Hospital General Universitario y Hospital Clínico Universitario de la ciudad de Valencia, provincia de Valencia. De éstos aislados, 126 fueron identificados por métodos convencionales y moleculares como MTBC, correspondientes a 106 pacientes. La cepa control Mycobacterium tuberculosis ATCC 25177 también fue identificada como tal mediante este método. La técnica AFLPs permitió agrupar a las cepas en doce patrones (P1 a P8, P10, P12, P13, P14), de los cuales los más prevalentes fueron los patrones P1 y P2 con 77 (61,1%) y 27 (21,4%) aislados respectivamente, lo que supone el 82,5% del total de los mismos. Le siguieron en frecuencia el patrón P5 con 5 (3,9%) aislados, los patrones P3, P4 y P6 agruparon a 3 aislados cada uno (2,4%), los patrones P8 y P12 con 2 aislados (1,6%) y finalmente los patrones P7, P10, P13 y P14 con 1 aislado cada uno (0,8%). La cepa control M. tuberculosis ATCC 25177, mostró un perfil de restricción que no permitió su inclusión en ninguno de los patrones descritos. El poder discriminatorio del método (HGDI) fue de 0,5812 frente a 0.9843 de la técnica MIRU-15, que agrupó a 69 cepas (54,8%) en 20 complejos clonales y 57 patrones únicos (45,2%). Para el caso de España, las cepas estuvieron relacionadas en su mayoría con el linaje 4 o Euro-Americano que incluye: Cammeroon (1,59%), Haarlem (36,51%), S (31,75%), y LAM (19,05%); el linaje 6 o West Africa I (9,53%), el linaje 1 o EIA (1,59%), Para el caso de Ecuador las cepas estaban relacionadas con el linaje 4: Haarlem (42,86%), S (33,33%), y LAM (22,22%) y el linaje 2 Beijing (1,59%) originario de Asia. La técnica MIRU-VNTR (15 loci) demostró ser un sistema estable, reproducible y con un poder discriminatorio alto en comparación con AFLPs lo que permitiría emplearlo para realizar estudios poblacionales prospectivos con la finalidad de contribuir a los programas de Salud Pública para el control de la Tuberculosis (TB). / [CAT] En els últims anys s'han desenvolupat diverses tècniques de genotipificació per aïllats de Mycobacterium tuberculosis complex (MTBC) que han demostrat tenir un alt poder discriminatori. En aquest estudi, després de la identificació de les soques seleccionades al nivell d'espècie mitjançant la tècnica comercial GenoType MTBC, s'ha avaluat la utilitat de la tècnica simplificada del Polimorfisme de longitud de fragments amplificats (AFLPs) i la tècnica d'Unitats repetitives Intercalades micobacterianes (Miru-15). Es van analitzar un total de 131 aïllats clínics dels quals 68 aïllats van ser recollectats a Equador, provinents tant del Laboratori Clínic de l'Hospital Alli Causai situat a la ciutat d'Ambato, província de Tungurahua com del Laboratori de Bacteriologia de l'Hospital Carlos Andrade Marín ubicat a la ciutat cabdal Quito, província de Pichincha. Els 63 aïllats restants van ser recollectats a Espanya i pertanyien a la collecció de microorganismes dels Serveis de Microbiologia del Consorci Hospital General Universitari i Hospital Clínic Universitari de la ciutat de València, província de València. D'aquests aïllats, 126 van ser identificats per mètodes convencionals i moleculars com MTBC, corresponents a 106 pacients. La soca control Mycobacterium tuberculosi ATCC 25177 també va ser identificada com a tal mitjançant aquest mètode. La tècnica AFLPs va permetre agrupar les soques en dotze patrons (P1 a P8, P10, P12, P13, P14), dels quals els més prevalents van ser els patrons P1 i P2 amb 77 (61,1%) i 27 (21, 4%) aïllats respectivament, fet que suposa el 82,5% del total dels mateixos. El van seguir en freqüència el patró P5 amb 5 (3,9%) aïllats, els patrons P3, P4 i P6 van agrupar a 3 aïllats cadascun (2,4%), els patrons P8 i P12 amb 2 aïllats (1,6%) i finalment els patrons P7, P10, P13 i P14 amb 1 aïllat cadascun (0,8%). La soca control M. tuberculosis ATCC 25177, va mostrar un perfil de restricció que no va permetre la seva inclusió en cap dels patrons descrits. El poder discriminatori del mètode (HGDI) va ser de 0,5812 enfront de 0,9843 de la tècnica MIRU-15, que va agrupar a 69 soques (54,8%) en 20 complexos clonals i 57 patrons únics (45,2%). Per al cas d'Espanya, les soques van estar relacionades majoritàriament amb el llinatge 4 o Euro-Americà que inclou: Cammeroon (1,59%), Haarlem (36,51%), S (31,75%), i LAM (19,05%); el llinatge 6 o West Africa I (9,53%), el llinatge 1 o EIA (1,59%), Pel cas de l'Equador les soques estaven relacionades amb el llinatge 4: Haarlem (42,86%), S ( 33,33%), i LAM (22,22%) i el llinatge 2 Beijing (1,59%) originari d'Àsia. La tècnica Miru-VNTR (15 loci) va demostrar ser un sistema estable, reproduïble i amb un poder discriminatori alt en comparació amb AFLPs, el que permetria emprar-lo per realitzar estudis poblacionals prospectius amb la finalitat de contribuir als programes de salut pública per al control de la Tuberculosi (TB). / Jiménez Arias, AP. (2016). Genotipificación de Mycobacterium tuberculosis complex mediante herramientas moleculares [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62681 / TESIS

La pirazinamida (PZA) es una droga antituberculosa de primera línea, presenta gran actividad in vivo, sin embargo in vitro no es evidente a menos que el pH del medio sea ácido, lo que hace que la susceptibilidad sea difícil de determinar por métodos convencionales. Por lo tanto, el objetivo del presente estudio fue evaluar la prueba molecular Polimorfismo Conformacional de la Hebra simple de ADN (SSCP) en cepas clínicas de Mycobacterium tuberculosis, así como comparar su desempeño con otras pruebas como son el BACTECÔ-460TB, el test de Wayne y el secuenciamiento. Se utilizó la prueba molecular del SSCP para la determinación de la susceptibilidad a PZA trabajando con 157 aislamientos clínicos de M. tuberculosis provenientes del Área de Tuberculosis del Laboratorio de Enfermedades Infecciosas de la Universidad Peruana Cayetano Heredia. / Tesis