Clostridium perfringens in central Colombia: frequency, toxin genes, and risk factors.

Clostridium perfringens is an opportunistic bacterium that causes intestinal diseases in both humans and animals. This study aimed to assess the frequency of C. perfringens and the presence of toxin-encoding genes in fecal samples from individuals with or without gastrointestinal symptoms in the Department of Boyacá, Colombia. Additionally, risk factors associated with carriage and disease development were analyzed. A total of 114 stool samples were analyzed using a molecular test based on specific polymerase chain reaction (PCR) targeting 16S-rRNA and alpha toxin (cpa) genes. For individuals with a positive result for the PCR test, stool samples were cultured on Tryptose Sulfite Cycloserine (TSC) agar. Two to five colonies forming units were selected based on phenotypic characteristics, resulting in 56 bacterial isolates. These isolates were then analyzed for toxin-coding genes associated with gastrointestinal diseases. In addition, sociodemographic and clinical data from 77 individuals were also analyzed. The overall frequency of C. perfringens was 19.3% (n = 22/114). The detection frequency in 77 individuals with clinical data was 16.6% (n = 5/30) among symptomatic individuals and 21.2% (n = 10/47) among asymptomatic individuals. All 56 isolates obtained carried the cpa gene, while cpb2 was present in 10.7% (n = 6/56); cpe and cpb genes were not detected. Notably, diabetes and autoimmune diseases are significantly associated with an increased risk of C. perfringens detection (adjusted OR 8.41: 95% CI 1.32-35.89). This study highlights an elevated frequency of C. perfringens and the presence of the cpb2 gene in asymptomatic individuals compared with their symptomatic counterparts. These findings offer insights into the distribution and virulence factors of C. perfringens at a micro-geographical level. This information supports the need for developing tailored prevention strategies based on local characteristics to promote active surveillance programs based on molecular epidemiology.

Comparative evaluation of lateral flow assays to diagnose chronic Trypanosoma cruzi infection in Bolivia.

Bolivia has the highest incidence of Chagas disease (CD) worldwide. Caused by the parasite Trypanasoma cruzi, CD is generally a chronic condition. Diagnosis is logistically and financially challenging, requiring at least two different laboratory-based serological tests. Many CD cases are missed; in Bolivia it is estimated just 6% of individuals chronically infected with T. cruzi get diagnosed. Achieving control on the way to elimination of CD requires a radical simplification of the current CD testing pathways, to overcome the barriers to accessing CD treatment. We aimed to generate unbiased performance data of lateral flow assays (LFAs) for T. cruzi infection in Bolivia, to evaluate their usefulness for improving T. cruzi diagnosis rates in a precise and efficient manner. This retrospective, laboratory-based, diagnostic evaluation study sought to estimate the sensitivity/specificity of 10 commercially available LFAs for T. cruzi, using the current CD diagnostic algorithm employed in Bolivia as the reference test method. All tests were blinded at the study site and performed by three operators. In total, 470 serum samples were tested, including 221 and 249 characterized as CD-positive/-negative, respectively. The LFAs were scored according to their relative importance using a decision-tree-based algorithm, with the mean decrease in Gini index as the scoring metric. The estimates of sensitivities ranged from 62.2-97.7% (95% confidence interval (CI) lower bound 55.0-94.7%); for specificities the range was 78.6-100% (95% CI lower bound 72.0-97.5%); 5/10 and 6/10 tests had sensitivity >90% and specificity >95%, respectively. Four LFAs showed high values of both sensitivity (93-95%) and specificity (97-99%). The agreement between 6 LFAs and the reference tests was almost perfect (Kappa 0.83-0.94). Most LFAs evaluated thus showed performances comparable with current laboratory-based diagnostic methods.

Comparative evaluation of four rapid diagnostic tests that detect human Trypanosoma cruzi-specific antibodies to support diagnosis of Chagas Disease in urban population of Argentina.

BACKGROUND: Chagas disease (CD), caused by the parasite Trypanosoma cruzi, is the most important endemic anthropozoonosis in Argentina. Since 2010, the World Health Organization has highlighted the urgent need to validate diagnostic systems that allow rapid detection of T. cruzi, infection in primary healthcare centers. Serological rapid diagnostic tests (RDTs) for T. cruzi, infection could be used to improve case management, as RDTs do not require specialized laboratories or highly trained staff to use them. We aimed to generate unbiased performance data of RDTs in Argentina, to evaluate their usefulness for improving T. cruzi, diagnosis rates. METHODS AND PRINCIPAL FINDINGS: This is a retrospective, laboratory-based, diagnostic evaluation study to estimate the clinical sensitivity/specificity of four commercially available RDTs for T. cruzi, using the Chagas disease diagnostic algorithm currently used in Argentina as the reference standard. In total, 400 serum samples were tested, 200 from individuals with chronic T. cruzi infection and 200 from individuals not infected with T. cruzi. All results were registered as the agreement of at least two operators who were blinded to the reference standard results. The sensitivity estimates ranged from 92.5-100% (95% confidence interval (CI) lower bound 87.9-98.2%); for specificity, the range was 76-96% (95% CI lower bound 69.5-92.3%). Most RDTs evaluated showed performances comparable with the reference standard method, showing almost perfect concordance (Kappa 0.76-0.92). CONCLUSIONS: Our study demonstrates that, under controlled laboratory conditions, commercially available RDTs for CD have a performance comparable to the Argentinian diagnostic algorithm, which is based on laboratory-based serological tests. For the next stage of our work, the RDTs will be evaluated in real-world settings.

Metabolic and chromosomal changes in a Bacillus subtilis whiA mutant.

IMPORTANCE: WhiA is a conserved DNA-binding protein that influences cell division in many Gram-positive bacteria and, in B. subtilis, also chromosome segregation. How WhiA works in Bacillus subtilis is unknown. Here, we tested three hypothetical mechanisms using metabolomics, fatty acid analysis, and chromosome confirmation capture experiments. This revealed that WhiA does not influence cell division and chromosome segregation by modulating either central carbon metabolism or fatty acid composition. However, the inactivation of WhiA reduces short-range chromosome interactions. These findings provide new avenues to study the molecular mechanism of WhiA in the future.

Laboratory evaluation of eleven rapid diagnostic tests for serological diagnosis of Chagas disease in Colombia.

BACKGROUND: Chagas disease is a public health challenge in Colombia, where only an estimated 1.2% of people at risk have accessed diagnosis, while less than 0.5% of affected people have obtained treatment. The development of simplified diagnostic algorithms would enable progress in access to diagnosis; however, the current diagnostic algorithm relies on at least two laboratory-based tests that require qualified personnel, processing equipment, and infrastructure, which are still generally lacking at the primary care level. Rapid diagnostic tests (RDTs) for Chagas disease could simplify diagnosis, but their performance in the epidemiological context of Colombia is not well known. METHODOLOGY: A retrospective analytical observational study of RDTs was performed to estimate the operational characteristics of 11 commercially available RDTs designed for in vitro detection of anti-T. cruzi IgG antibodies. The study was performed under controlled laboratory conditions using human serum samples. PRINCIPAL FINDINGS: Eleven RDTs were assessed, ten using 585 serum samples and one using 551 serum samples. Employing the current national diagnostic algorithm as a reference standard for serological diagnosis of chronic infection, the sensitivity of the assessed RDTs ranged from 75.5% to 99.0% (95% CI 70.5-100), while specificity ranged from 70.9% to 100% (95% CI 65.3-100). Most tests (7/11, 63.6%) had sensitivity above 90%, and almost all (10/11, 90.9%) had specificity above 90%. Five RDTs had both sensitivity and specificity above 90%. CONCLUSIONS/SIGNIFICANCE: The evaluation of these 11 commercially available RDTs under controlled laboratory conditions is a first step in the assessment of the diagnostic performance of RDTs in Colombia. As a next step, field studies will be conducted on available RDTs with sensitivity and specificity greater than 90% in this study, to evaluate performance in real world conditions, with the final goal to allow simplified diagnostic algorithms.

Do we need to change our perspective about gut biomarkers? A public data mining approach to identify differentially abundant bacteria in intestinal inflammatory diseases.

Introduction: The gut microbiome is involved in multiple processes that influence host physiology, and therefore, disruptions in microbiome homeostasis have been linked to diseases or secondary infections. Given the importance of the microbiome and the communities of microorganisms that compose it (microbiota), the term biomarkers were coined, which are bacteria correlated with disease states, diets, and the lifestyle of the host. However, a large field in the study of intestinal biomarkers remains unexplored because the bacterial communities associated with a given disease state have not been exactly defined yet. Methods: Here, we analyzed public data of studies focused on describing the intestinal microbiota of patients with some intestinal inflammatory diseases together with their respective controls. With these analyses, we aimed to identify differentially abundant bacteria between the subjects with the disease and their controls. Results: We found that frequently reported bacteria such as Fusobacterium, Streptococcus, and Escherichia/Shigella were differentially abundant between the groups, with a higher abundance mostly in patients with the disease in contrast with their controls. On the other hand, we also identified potentially beneficial bacteria such as Faecalibacterium and Phascolarctobacterium, with a higher abundance in control patients. Discussion: Our results of the differentially abundant bacteria contrast with what was already reported in previous studies on certain inflammatory diseases, but we highlight the importance of considering more comprehensive approaches to redefine or expand the definition of biomarkers. For instance, the intra-taxa diversity within a bacterial community must be considered, as well as environmental and genetic factors of the host, and even consider a functional validation of these biomarkers through in vivo and in vitro approaches. With the above, these key bacterial communities in the intestinal microbiota may have potential as next-generation probiotics or may be functional for the design of specific therapies in certain intestinal diseases.

The CUIDA Chagas Project: towards the elimination of congenital transmission of Chagas disease in Bolivia, Brazil, Colombia, and Paraguay.

BACKGROUND: Mother-to-child transmission of Chagas disease (CD) has become a relevant problem in both endemic and non-endemic areas. METHODS: Description of the CUIDA Chagas Project - Communities United for Innovation, Development and Attention for Chagas disease'. RESULTS: Through innovative and strategic research, this project will provide improved diagnostic and treatment options as well as replicable implementation models that are adaptable to different contexts. CONCLUSIONS: By integrating test, treat and care actions for CD into primary health care practices, the burden of CD on people and health systems may be significantly reduced.

The CUIDA Chagas Project: towards the elimination of congenital transmission of Chagas disease in Bolivia, Brazil, Colombia, and Paraguay

ABSTRACT Background: Mother-to-child transmission of Chagas disease (CD) has become a relevant problem in both endemic and non-endemic areas. Methods: Description of the CUIDA Chagas Project - Communities United for Innovation, Development and Attention for Chagas disease'. Results: Through innovative and strategic research, this project will provide improved diagnostic and treatment options as well as replicable implementation models that are adaptable to different contexts. Conclusions: By integrating test, treat and care actions for CD into primary health care practices, the burden of CD on people and health systems may be significantly reduced.

Mitochondrial Genetic Diversity, Population Structure and Detection of Antillean and Amazonian Manatees in Colombia: New Areas and New Techniques.

The Antillean manatee (Trichechus manatus) and the Amazonian manatee (Trichechus inunguis) are distributed in rivers in the Caribbean and Amazonian region of Colombia respectively. For 30 years, genetic information has been obtained from these populations in order to inform conservation programs for these endangered species and decide on the location to release them back to the wild. However, in previous studies, samples from rivers in some areas of the country were not included, given the difficulties to access these regions due to either logistic or safety issues. In this study, we analyzed mitochondrial DNA (mtDNA) control region (CR) sequences of from samples of T. manatus (n = 37) and T. inunguis (n = 4) (410 and 361 bp, respectively), obtained in new and previously unexplored rivers and bays in the country, including Santa Marta, Urabá Gulf, Ayapel Marsh (San Jorge River Basin), Meta River and Magdalena Medio and the low Magdalena River (Cesar Province and Canal del Dique) as well as additional samples from Puerto Nariño in the Colombian Amazon. Our results included the discovery of two newly described mtDNA CR haplotypes for T. manatus. In addition, we confirmed significant population differentiation at the mitochondrial level between the Magdalena and Sinú rivers and differentiation among areas of the same river, including the middle and low Magdalena River. This differentiation may be related to anthropic changes in the river since construction of the Canal del Dique in the XVI century. We also tested environmental DNA sampling and analyses techniques to evaluate its potential use for manatee detection and monitoring in bodies of water in Colombia, in order to evaluate new areas for future manatee conservation initiatives. We emphasize the need to continue using genetic information to provide evidence on the potential best locations to undertake animal release to prevent outbreeding depression.

The PASTA domains of Bacillus subtilis PBP2B strengthen the interaction of PBP2B with DivIB.

Bacterial cell division is mediated by a protein complex known as the divisome. Many protein-protein interactions in the divisome have been characterized. In this report, we analyse the role of the PASTA (Penicillin-binding protein And Serine Threonine kinase Associated) domains of Bacillus subtilis PBP2B. PBP2B itself is essential and cannot be deleted, but removing the PBP2B PASTA domains results in impaired cell division and a heat-sensitive phenotype. This resembles the deletion of divIB, a known interaction partner of PBP2B. Bacterial two-hybrid and co-immunoprecipitation analyses show that the interaction between PBP2B and DivIB is weakened when the PBP2B PASTA domains are removed. Combined, our results show that the PBP2B PASTA domains are required to strengthen the interaction between PBP2B and DivIB.

Molecular Bases of Drug Resistance in Hepatocellular Carcinoma.

The poor outcome of patients with non-surgically removable advanced hepatocellular carcinoma (HCC), the most frequent type of primary liver cancer, is mainly due to the high refractoriness of this aggressive tumor to classical chemotherapy. Novel pharmacological approaches based on the use of inhibitors of tyrosine kinases (TKIs), mainly sorafenib and regorafenib, have provided only a modest prolongation of the overall survival in these HCC patients. The present review is an update of the available information regarding our understanding of the molecular bases of mechanisms of chemoresistance (MOC) with a significant impact on the response of HCC to existing pharmacological tools, which include classical chemotherapeutic agents, TKIs and novel immune-sensitizing strategies. Many of the more than one hundred genes involved in seven MOC have been identified as potential biomarkers to predict the failure of treatment, as well as druggable targets to develop novel strategies aimed at increasing the sensitivity of HCC to pharmacological treatments.

The Conserved DNA Binding Protein WhiA Influences Chromosome Segregation in Bacillus subtilis.

The DNA binding protein WhiA is conserved in Gram-positive bacteria and is present in the genetically simple cell wall-lacking mycoplasmas. The protein shows homology to eukaryotic homing endonucleases but lacks nuclease activity. WhiA was first characterized in streptomycetes, where it regulates the expression of key differentiation genes, including the cell division gene ftsZ, which is essential for sporulation. For Bacillus subtilis, it was shown that WhiA is essential when certain cell division genes are deleted. However, in B. subtilis, WhiA is not required for sporulation, and it does not seem to function as a transcription factor, despite its DNA binding activity. The exact function of B. subtilis WhiA remains elusive. We noticed that whiA mutants show an increased space between their nucleoids, and here, we describe the results of fluorescence microscopy, genetic, and transcriptional experiments to further investigate this phenomenon. It appeared that the deletion of whiA is synthetic lethal when either the DNA replication and segregation regulator ParB or the DNA replication inhibitor YabA is absent. However, WhiA does not seem to affect replication initiation. We found that a ΔwhiA mutant is highly sensitive for DNA-damaging agents. Further tests revealed that the deletion of parAB induces the SOS response, including the cell division inhibitor YneA. When yneA was inactivated, the viability of the synthetic lethal ΔwhiA ΔparAB mutant was restored. However, the nucleoid segregation phenotype remained. These findings underline the importance of WhiA for cell division and indicate that the protein also plays a role in DNA segregation.IMPORTANCE The conserved WhiA protein family can be found in most Gram-positive bacteria, including the genetically simple cell wall-lacking mycoplasmas, and these proteins play a role in cell division. WhiA has some homology with eukaryotic homing endonucleases but lacks nuclease activity. Because of its DNA binding activity, it is assumed that the protein functions as a transcription factor, but this is not the case in the model system B. subtilis The function of this protein in B. subtilis remains unclear. We noticed that a whiA mutant has a mild chromosome segregation defect. Further studies of this phenomenon provided new support for a functional role of WhiA in cell division and indicated that the protein is required for normal chromosome segregation.

Effect of Genome Position on Heterologous Gene Expression in Bacillus subtilis: An Unbiased Analysis.

A fixed gene copy number is important for the in silico construction of engineered synthetic networks. However, the copy number of integrated genes depends on their genomic location. This gene dosage effect is rarely addressed in synthetic biology. Two studies in Escherichia coli presented conflicting data on the impact of gene dosage. Here, we investigate how genome location and gene orientation influences expression in Bacillus subtilis. An important difference with the E. coli studies is that we used an unbiased genome integration approach mediated by random transposon insertion. We found that there is a strong gene dosage effect in fast growing B. subtilis cells, which can amount to a 5-fold difference in gene expression. In contrast, gene orientation with respect to DNA replication direction does not influence gene expression. Our study shows that gene dosage should be taken into account when designing synthetic circuits in B. subtilis and presumably other bacteria.

Leptina y lactancia materna: beneficios fisiológicos / Breastfeeding and leptin: physiological benefits

Antecedentes. La leptina se asocia al control del apetito y a la regulación del gasto energético; además, cumple con otras funciones diversas en el organismo, por ejemplo en la lactancia materna, la cual ha sido poco estudiada y requiere más estudios al respecto. Objetivo. Identificar si existe o no evidencia de los beneficios fisiológicos de la leptina para la madre, durante el periodo de lactancia. Materiales y métodos. Búsqueda sistemática en las siguientes bases de datos: ElSevier, PubMed, EBSCo, ScienceDirect, Scielo, Access Medicine, NCBI, Medline, Clinical Key ElSevier, Academic Search Complete y Jstor con términos MeSH.Como criterios de inclusión se tomaron artículos de revisión, revisiones sistemáticas, investigaciones descriptivas, experimentales y causiexperimentales en inglés o español, en el periodo comprendido entre 2003 y 2014. Resultados. Se revisaron 52 artículos. De estos, se excluyeron aquellos cuyo aporte no contaba con suficiente evidencia (determinada por el número de sujetos en la muestra empleada), el año de realización o la relevancia de sus resultados. Se encontró que la leptina más allá de cumplir con múltiples funciones metabólicas, como controlar el apetito y saciedad; también juega un papel importante como agente protector ante posibles infecciones o enfermedades tales como el cáncer y la regulación de la tensión arterial. Asimismo ayuda en la regulación emocional en la madre lactante y, en la producción de prolactina, hormona implicada en la producción de la leche. Conclusión. La lactancia materna no solamente tiene beneficios para el infante, sino que también para la madre, en tanto que se la ha relacionado con la activación de cadenas de señalización de leptina, las cuales disminuyen los riesgos de enfermedades como hipertensión, obesidad, cáncer y depresión, entre otras.

Background. Leptin is associated with appetite control and regulation of energy expenditure, however meets many diverse functions in the body, the role of leptin in breastfeeding has been little studied and yet more studies are required. Objective. Identify whether there is evidence of the physiological benefits to the mother of leptin during lactation period. Materials and methods. Available scientific literature, included in the ElSevier, PubMed, EBSCo, ScienceDirect, Scielo, AccessMedicine, NCBI, Medline, Clinical Key ElSevier, Academic Search Complete and Jstor database. The article´s selection was made evaluating the relevance with review´s topic. The inclusion criteria were review articles, systematic reviews in Spanish and English. Results. The review included only 52 articles which have important scientific evidence. Some articles were excluded because their information is not about with the review or does not have enough scientific evidence. The leptin is important above and beyond its metabolic functions, is a mediator in appetite and satiety control, inflammatory response, among others. It is related as a protector factor in specific diseases like cancer, infections, hormonal regulation an arterial pressure. Conclusion. Breastfeeding not only has nutritional facts in infants, it has physiological benefits in mothers as well. It has been related with signaling pathways of leptin that decreases the risks in development of chronic diseases like cancer, obesity, hypertension and depression,among others.

Neotropical Andes hot springs harbor diverse and distinct planktonic microbial communities.

Microbial explorations of hot springs have led to remarkable discoveries and improved our understanding of life under extreme conditions. The Andean Mountains harbor diverse habitats, including an extensive chain of geothermal heated water sources. In this study, we describe and compare the planktonic microbial communities present in five high-mountain hot springs with distinct geochemical characteristics, at varying altitudes and geographical locations in the Colombian Andes. The diversity and structure of the microbial communities were assessed by pyrosequencing the V5 - V6 region of the 16S rRNA gene. The planktonic communities varied in terms of diversity indexes and were dominated by the bacterial phyla Proteobacteria, Aquificae, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae, and Thermotogae, with site-specific bacterial taxa also observed in some cases. Statistical analyses showed that these microbial communities were distinct from one another and that they clustered in a manner consistent with physicochemical parameters of the environment sampled. Multivariate analysis suggested that pH and sulfate were among the main variables influencing population structure and diversity. The results show that despite their geographical proximity and some shared geochemical characteristics, there were few shared operational taxonomic units (OTUs) and that community structure was influenced mainly by environmental factors that have resulted in different microbial populations.

Genes para proteorodopsinas en aguas termales de los Andes colombianos / Genes for proteorhodopsins in hot springs in the Colombian Andes

La identificación de genes para proteorodopsinas en aguas termales amplía el rango de ecosistemas en los cuales se encuentran estos genes, los que codifican para bombas de protones y pueden estar implicados en la productividad de estas comunidades microbianas acuáticas. (AU)

Genes para proteorodopsinas en aguas termales de los Andes colombianos / Genes for proteorhodopsins in hot springs in the Colombian Andes

La identificación de genes para proteorodopsinas en aguas termales amplía el rango de ecosistemas en los cuales se encuentran estos genes, los que codifican para bombas de protones y pueden estar implicados en la productividad de estas comunidades microbianas acuáticas.

Proteorhodopsin-like genes present in thermoacidophilic high-mountain microbial communities.

Proteorhodopsin (PR) sequences were PCR amplified from three Andean acidic hot spring samples. These sequences were similar to freshwater and marine PRs and they contained residues indicative of proton-pumping activity and of proteins that absorb green light; these findings suggest that PRs might contribute to cellular metabolism in these habitats.

In-depth characterization via complementing culture-independent approaches of the microbial community in an acidic hot spring of the Colombian Andes.

The microbial community of a Colombian high mountain hot spring, El Coquito, was analyzed using three different culture-independent assessments of 16S ribosomal RNA genes: clone libraries, pyrosequencing of the V5-V6 hypervariable region, and microarray. This acidic spring had a diverse community composed mainly of Bacteria that shared characteristics with those from other hot springs and extreme acidic environments. The microbial community was dominated by Proteobacteria, Firmicutes, and Planctomycetes and contained chemotrophic bacteria potentially involved in cycling of ferrous and sulfur-containing minerals and phototrophic organisms, most of which were eukaryotic micro-algae. Despite the presence of a large proportion of novel, unclassified sequences, the taxonomic profiles obtained with each strategy showed similarities at higher taxonomic levels. However, some groups, such as Spirochaetes and Aquificae, were identified using only one methodology, and more taxa were detected with the gene array, which also shared more groups with the pyrosequencing data. Overall, the combined use of different approaches provided a broader view of the microbial community in this acidic hot spring.

LA PROTEÍNA PTHB DE Xanthomonas axonopodis pv. Manihotis ES AUTOACTIVA EN ENSAYOS DE DOBLE HÍBRIDO / The PthB Protein from Xanthomonas axonopodis pv. Manihotis is an Autoactive in Yeast Two-Hybrid Assays

La bacteriosis vascular de yuca producida por la bacteria Xanthomonas axonopodis pv. manihotis (Xam) es una enfermedad limitante para la producción de yuca. Dentro de los primeros factores de patogenicidad identificados en esta bacteria se encuentra el gen PthB. La proteína PthB pertenece a la familia de efectores PthA/AvrBs3, que se caracterizan por presentar dominios NLS (Nuclear Localization Signal) y un dominio AAD (Acidic Activation Domain), lo cual sugiere que estas proteínas actúan como factores de transcripción. La identificación de las proteínas de yuca que interactúan con PthB permitiría dar luces sobre la función de esta proteína en la patogenicidad de esta bacteria. En este trabajo se clonó PthB en una fusión traduccional con el BD (Binding Domain) del factor de transcripción GAL4. Después de transformar este constructo en una cepa de levadura, se observó autoactivación de los genes reporteros, incluso a concentraciones altas de 3-AT. La eliminación del primer, segundo o de los dos NLS y del AAD no eliminaron la capacidad de autoactivación de los genes reporteros mediada por PthB. Estos resultados indican la imposibilidad de su utilización en un tamizaje de una librería de ADNc de yuca para identificar las proteínas que interactúan con PthB.

Cassava bacterial blight disease is caused by the gram-negative bacteria Xanthomonas axonopodis pv. manihotis (Xam), and constitutes one of the most important constraints for cassava production. One of the first determinants of pathogenicity identified in this bacterium is the PthB gene. The PthB protein belongs to the PthA/AvrBs3 family, characterized by the presence of Nuclear Localization Signal (NLS) and Acidic Activation (AAD) domains, suggesting that these proteins are transcription factors. The identification of cassava proteins interacting with PthB could give insights about the function of this protein in the pathogenicity of this bacterium. In this work we cloned PthB in the yeast two hybrid expression vector pLAW10, generating a fusion protein with the Binding Domain (BD) of the transcription factor GAL4. In this work, PthB was cloned in a translational fusion with Gal4-BD (DNA Binding Domain). After transforming this construct into a yeast strain, autoactivation of the reporter genes was observed, even at the highest concentrations of 3-AT. The deletion of the first, second or both NLS and the AAD did not eliminate the ability of autoactivation of PthB. These results show the impossibility of using PthB to screen a cassava cDNA library to identify the proteins interacting with PthB.