Pedro Silva

• PhD
• Professor (Full) at Federal University of Rio Grande

Despite the many advances in drug research, natural products are still being explored as a promising source for discovering new bio-active compounds to treat global diseases such as tuberculosis. However, there is a lack of studies and information about coastal natural products, which thrive in the transitional environment between two different eco...

Tuberculosis (TB) and infectious diseases caused by non-tuberculous mycobacteria (NTM) are global concerns. The development of a rapid and accurate diagnostic method, capable of detecting and identifying different mycobacteria species, is crucial. We propose a molecular approach, the BiDz-TB/NTM, based on the use of binary deoxyribozyme (BiDz) sens...

Introduction: Mycobacterium tuberculosis genotyping has impacted evolutionary studies worldwide. Nonetheless, its application and the knowledge generated depend on the genetic marker evaluated and the detection technologies that have evolved over the years. Here we describe the timeline of main genotypic methods related to M. tuberculosis in Latin...

The emergence and reemergence of mosquito-borne diseases in Brazil such as yellow fever, zika, chikungunya, and dengue have had serious impacts on public health. Concerns have been raised due to the rapid dissemination of the chikungunya virus across the country since its first detection in 2014 in Northeast Brazil. In this work, we carried out on-...

Objective: To describe trends in the prevalence of diabetes mellitus (DM) in Brazil and to analyze its association with the consumption of artificially sweetened beverages among individuals aged 18 years or older. Study design: This was a repeated cross-sectional study. Methods: Annual data from VIGITEL surveys (2006-2020) were used, which inc...

Zika virus (ZIKV) and Dengue Virus (DENV) share a lot of similarities, being both flaviviruses and neglected tropical diseases that cause a worldwide burden that is increasing with climate change. Studying the interactions of cell recptors and viruses is essential to further the knowledge and development of ways to prevent and control flaviviral di...

The emergence and reemergence of mosquito-borne diseases in Brazil such as Yellow Fever, Zika, Chikungunya, and Dengue have had serious impacts on public health. Concerns have been raised due to the rapid dissemination of the chikungunya virus (CHIKV) across the country since its first detection in 2014 in Northeast Brazil. Faced with this scenario...

Tuberculosis (TB) has a high incidence in several countries and is even more severe in prisoners. We evaluated the completeness of prisoners TB notifications in the Notifiable Disease Information System (SINAN) carried out by prison primary care teams (eAPP) or by other health facilities in the state of Rio Grande do Sul (RS). This descriptive cros...

Resumo A tuberculose (TB) apresenta incidências elevadas em todo o mundo, sendo ainda mais grave em pessoas privadas de liberdade (PPL). Foi avaliada a completude das notificações de TB de PPL no SINAN realizadas por equipes de atenção primária prisional (eAPP) ou por outros estabelecimentos de saúde do RS. Estudo descritivo, transversal, utilizand...

Tuberculosis (TB) is a serious infectious disease, and its control is considered a challenge, especially among vulnerable populations such as prisoners. The occurrence of TB in prisons is an alarming public health problem in many countries. This integrative review aims to describe the epidemiology of TB and control strategies for this disease in co...

Objective: The study aimed to evaluate molecular and immunological methods and to propose a workflow using them for tuberculosis (TB) diagnosis routine. Methods: A cross-sectional retrospective study was performed, including 121 liquid cultures from a TB laboratory located in the extreme south of Brazil. All cultures were positive for Mycobacterium...

Background: Tuberculosis is a worldwide public health problem and is more prevalent in specific populations, such as prisoners. The aim of this study was to analyze the epidemiological and operational indicators of tuberculosis in prisoners in a southern region of Brazil. Methods: This was a descriptive, observational study, utilizing secondary...

Despite a considerable number of new antibiotics under going clinical trials, treatment of intracellular pathogens still represents a major pharmaceutical challenge. The use of lipid nanocarriers provides several advantages such as protection from compound degradation, increased bioavailability, and controlled and targeted drug release. Wheat germ...

Background and objectives: to understand the impact of the COVID-19 pandemic on tuberculosis (TB) diagnosis in different settings is essential to guide the establishment of appropriate TB control strategies. This study aimed to assess the influence of COVID-19 pandemic in laboratory diagnosis of TB in patients tested and diagnosed for TB. Methods:...

Background: Tuberculosis (TB) remains a serious public health problem, with approximately 10 million new cases reported annually. Knowledge about the quantitative evolution of theses and dissertations (T&Ds) examining human TB in Brazil can contribute to generating strategic planning for training professionals in this field and disease control. Th...

Due to several obstacles in treating tuberculosis (TB), the search for new therapeutic alternatives remains a global priority. The nitrogenous heterocyclic compounds are promising in searching for new anti-Mycobacterium tuberculosis molecules, and our previous results highlight the potential of tetrahydropyridines. After exploring the antimycobacte...

Microalgae, due to its rapid growth, low nutritional requirements, and versatility of adaptation to different environmental conditions, has aroused the biotechnological interest, synthesizing novel molecules with antioxidant, anticoagulant, anti‐inflammatory, anti‐tumor, and antimicrobial activities. In this sense, we carried out the bioprospection...

Natural products have been touted as important tools because of their vast potential for the development of compounds with antimicrobial activity and the possible inhibitory activity and/or adjuvant resistance mechanisms. Propolis has been empirically used for many years for the treatment of diseases, mainly due to its antioxidant, anti inflammator...

Bovine tuberculosis (BTB) is an infectious disease worldwide distributed, caused by Mycobacterium bovis, which affects cattle and other animals, including humans. In Brazil, BTB is endemic and causes economic losses by reducing the productivity of livestock and loss of carcasses in the slaughterhouses. Molecular epidemiology has been used as a tool...

National border areas are special places for the spread of Mycobacterium tuberculosis (MTB). These regions concentrate vulnerable populations and constant population movements. Understanding the dynamics of the transmission of MTB is fundamental to propose control measures and to monitor drug resistance. We conducted a population-based prospective...

Despite being a curable disease, tuberculosis (TB) remains a public health problem worldwide mainly due to lengthy treatment, as well as its toxic effects, TB/HIV co-infection and the emergence of resistant Mycobacterium tuberculosis strains. These barriers reinforcing the need for development of new antimicrobial agents, that ideally should reduce...

With the growing body of knowledge on the contribution of efflux activity to Mycobacterium tuberculosis drug resistance, increased attention has been given to the use of efflux inhibitors as adjuvants of tuberculosis therapy. Here, we investigated how efflux activity modulates the levels of efflux between monoresistant and multi- and extensively dr...

Tuberculosis (TB) remains a major health problem within the Community of Portuguese Language Speaking Countries (CPLP). Despite the marked variation in TB incidence across its member-states and continued human migratory flux between countries, a considerable gap in the knowledge on the Mycobacterium tuberculosis population structure and strain circ...

Objective: The aims of this study were (1) to determine the frequency of plasmid-mediated resistance to fluoroquinolones (FQs) in Escherichia coli isolated from patients with urinary tract infections (UTIs) of nosocomial and community origin and (2) to determine the relationships between the presence of extended spectrum beta lactamases (ESBL), mu...

Background: Mycobacterium abscessus causes a wide range of clinical diseases that are difficult to treat. This microorganism is resistant not only to the classical antituberculosis agents but also to most of the antimicrobials that are currently available, resulting in limited therapeutic options and treatment failure. This scenario stresses the n...

Rifampicin is one of the most important chemotherapeutic agents used in the treatment of tuberculosis. M. tuberculosis clinical strains resistant to rifampicin harbor mainly mutation in an 81-base pair region of rpoB. These mutations mainly consist of single amino acid substitutions. However insertions also can be related with rifampicin resistance...

Numerous studies show efflux as a universal bacterial mechanism contributing to antibiotic resistance and also that the activity of the antibiotics subject to efflux can be enhanced by the combined use of efflux inhibitors. Nevertheless, the contribution of efflux to the overall drug resistance levels of clinical isolates of Mycobacterium tuberculo...

Meningococcus serogroup B (MenB), clonal complex 32 (cc 32), was the Brazilian epidemic strain of meningococcal disease (MD) in the 1990’s. Currently, meningococcus serogroup C (MenC), cc 103, is responsible for most of the cases of the disease in Brazil. The aim of this study was to investigate the seroprevalence of bactericidal antibody (SBA) aga...

Current diagnostic tools for Mycobacterium tuberculosis (Mtb) have many disadvantages including low sensitivity, slow turnaround times, or high cost. Accurate, easy to use, and inexpensive point of care molecular diagnostic tests are urgently needed for the analysis of multidrug resistant (MDR) and extensively drug resistant (XDR) Mtb strains that...

The objectives of this study were to evaluate tetrahydropyridine derivatives as efflux inhibitors and to understand the mechanism of action of the compounds by in silico studies. Minimum inhibitory concentration (MIC) determination, fluorometric methods and docking simulations were performed. The compounds NUNL02, NUNL09 and NUNL10 inhibited efflux...

Background Helicobacter pylori has a worldwide distribution and is associated with the pathogenesis of various diseases of the digestive system. Treatment to eradicate this microorganism involves the use of a combination of antimicrobials, such as amoxicillin, metronidazole, clarithromycin, and levofloxacin, combined with proton pump inhibitors. Al...

The emergence of multidrug and extensively drug-resistant tuberculosis represents a major threat to the control of the disease. Antimicrobial drug resistance in Mycobacterium tuberculosis is not merely a consequence of the occurrence of gene mutations in the drug targets but a balance between the acquisition of mutations and drug efflux. The low pe...

Infections caused by Mycobacterium tuberculosis and other mycobacteria are major challenges for global public health. Particularly worrisome are infections caused by multidrug-resistant bacteria, which are increasingly difficult to treat because of the loss of efficacy of the current antibacterial agents, a problem that continues to escalate worldw...

Justificativa e objetivos: A vasta biodiversidade amazônica tem sido apontada como uma fonte de produtos naturais candidatos a diversas atividades farmacológicas, principalmente no combate a doenças infecciosas. Algumas espécies, tais como as pertencentes ao gênero Duroia, da família Rubiaceae, têm sido caracterizadas pela produção de metabólitos s...

Justificativa e objetivos: Apesar de ser utilizado como um método de genotipagem para diferentes microrganismos, poucos estudos relatam a utilização de Multiple-Locus Variable Number of Tandem Repeats Analysis (MLVA) para análise da diversidade clonal do Helicobacter pylori. O objetivo deste estudo foi determinar a variabilidade genética de cepas d...

Justificativa e Objetivos: O estudo objetivou a avaliação da atividade antibacteriana de extratos brutos e frações de Ibicella lutea, na inibição do crescimento de Staphylococcus aureus, avaliando a combinação destes compostos e sua atividade citotóxica. Métodos: Para a atividade antibacteriana dos extratos foi utilizado o Teste de Microdiluição em...

Justificativa e objetivos: Helicobacter pylori é uma bactéria Gram negativa que coloniza o estômago de aproximadamente 50% da população humana mundial. Este microrganismo é o principal agente causal de gastrite e um importante fator de risco para o desenvolvimento de úlcera péptica e carcinoma gástrico. Os fatores que determinam essa diversidade de...

Resumo O estudo objetiva analisar o processo de detecção e tratamento de casos de tuberculose (TB) em um presídio do sul do Brasil. Realizou-se busca ativa e passiva para estimar a magnitude da TB entre uma população de 764 detentos. Simultaneamente às estratégias de detecção e ao seguimento clínico dos 41 casos confirmados, realizou-se observação...

Resumo Tuberculosis in Brazilian prisons: an integrative review of the literature O objetivo deste estudo foi sistematizar o conhecimento produzido sobre tuberculose em presídios brasileiros. Foi realizada uma revisão integrativa nas bases Medline, Lilacs e biblioteca eletrônica SciELO, com os descritores: “Tuberculosis”, “Prisons” e “Brazil”. Entr...

Recent advances in Bioinformatics and in Computer simulation and modelling have positively impacted the drug discovery process by turning viable the rational drug design (RDD). One of the major challenges in RDD is the understanding about protein-ligand interaction simulated at the atomic level by molecular docking algorithms. Virtual screening (VS...

Justificativa e objetivos: As fluoroquinolonas representam uma classe de antimicrobianos que é frequentemente prescrita no tratamento de infecções do trato urinário (ITU), tanto de origem hospitalar como originárias da comunidade. Este estudo tem como objetivo,determinar a frequência de resistência à ciprofloxacina e levofloxacina, além de seus fat...

Human toxocarosis is a chronic tissue parasitosis most often caused by Toxocara canis. The seroprevalence can reach up to 50%, especially among children and adolescents. The anthelmintics used in the treatment have moderate efficacy. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of quinones and their derivativ...

Introduction: The World Health Organization endorses the BACTEC Mycobacterial Growth Indicator Tube (MGIT)(tm) system as a rapid, sensitive, and specific method to diagnostic of tuberculosis. Here, we compared the performance of this system against Ogawa-Kudoh cultures and microscopy. Methods: A total of 927 samples were obtained between Decembe...

KEYWORDS: Helicobacter pylori. Polymerase Chain Reaction. Molecular Diagnostic Techniques

The present work aimed to evaluate the antimycobacterial activity and cytotoxicity of Microcystis aeruginosa toxins, the MC-LR variant and purified extract of [D-Leu(1)] microcystin-LR. The antimicrobial activity of M. aeruginosa extract and microcystin was evaluated by resazurin microtiter assay against Mycobacterium tuberculosis, M. terrae, M. ch...

We recently detected the spoligotype patterns of strains of Mycobacterium pinnipedii, a species of the Mycobacterium tuberculosis complex, in sputum samples from nine cases with pulmonary tuberculosis residing in Porto Alegre, South Brazil. Because this species is rarely encountered in humans, we further characterized these nine isolates by additio...

Bovine tuberculosis (BTB) remains an important economic and zoonotic problem in Latin America. Traditionally, the fight against BTB is initiated by the implementation of routine diagnostic tests for certification of free properties. The diagnosis of BTB can be made by direct and indirect methods, in which we can mention clinical, post mortem, histo...

Introduction: Reports of Mycobacterium tuberculosis resistant to multiple drugs are increasing globally and laboratories are becoming increasingly aware of the need for drug susceptibility testing. In recent years, due to the long time required by conventional drug susceptibility testing, new approaches have been proposed for faster detection of d...

Asymptomatic meningococcus carriers in hospitals is a risk factor for acquiring meningococcal disease. Meningococcal carrier (MC) frequency was investigated in oropharyngeal swab samples collected from 200 staff members at a teaching hospital from Brazil. MC prevalence was 9% (95% CI 5-13%). Risk factors associated with MC were: mean age of 26.5 ye...

The aim of this work was to develop and characterize nanoparticles as carriers of lapazine, a phenazine derived from β-lapachone; its antimycobacterial activity is described for the first time as a potential treatment for tuberculosis. The lapazine was synthesized, and by using gas chromatography coupled to a flame ionization detector, it was possi...

SETTING: Tuberculosis (TB) in prisons is a challenge for the public health system. Active and passive case screening are important tools for TB case detection. OBJECTIVE: To characterise TB in a southern Brazil prison in terms of epidemiological variables, diagnostic approaches and clinical isolate genotypes. DESIGN: Inmates of a southern Brazilian...

Introduction: Helicobacter pylori infection is associated with gastritis, peptic ulcer disease and gastric carcinoma. The severity of damage is determined by the interplay between environmental/behavioral factors, bacterial pathogenicity genes and host genetic polymorphisms that can influence the secretion levels of inflammatory cytokines. Accordin...

Anthelmintics used for intestinal helminthiasis treatment are generally effective; however, their effectiveness in tissue parasitosis (i.e. visceral toxocariasis) is moderate. The aim of this study was to evaluate the in vitro activity of lapachol, β-lapachone and phenazines in relation to the viability of Toxocara canis larvae. A concentration of...

CagA of Helicobacter pylori undergoes tyrosine phosphorylation in a region containing differing numbers of repeat sequences (EPIYAs), which can result in a modulation of the inflammatory response. This study investigated whether the presence of CagA EPIYA variations in strains of H. pylori that are positive for this region contributes to differing...

Fifteen naphthoquinones, sixteen phenazines and fifteen aryl triazoles were synthesized and evaluated against Mycobacterium tuberculosis. Twenty five substances are reported here for the first time and, among all of the compounds evaluated, six presented MIC (minimal inhibitory concentration) values ≤ 6.25 μg mL-1. These substances are promising an...

Drug resistant tuberculosis continues to increase and new approaches for its treatment are necessary. The identification of M. tuberculosis clinical isolates presenting efflux as part of their resistant phenotype has a major impact in tuberculosis treatment. In this work, we used a checkerboard procedure combined with the tetrazolium microplate-bas...

Drug susceptibility testing (DST) of rapidly growing mycobacteria (RGM) are recommended for guiding the antimicrobial therapy. We have evaluated the use of resazurin in Mueller-Hinton medium (MHR) for MIC determination of RGM and compared the results with those obtained with the reference standard broth microdilution in Mueller-Hinton (MH) and with...

Helicobacter pylori-induced gastric mucosal inflammation is mediated by proinflammatory and anti-inflammatory cytokines. Polymorphisms in genes that code cytokines influence cytokine secretion levels and appear to contribute to the risk of gastric diseases. In this sense, we performed this study to identify the polymorphisms in the IL-6, IL-8, and...

Human toxocariasis is a neglected public health problem. Infection of humans generally results from the accidental ingestion of embryonated Toxocara canis eggs, but it is important to broaden knowledge about other forms of transmission. This study aimed to demonstrate the prevalence of transmammary transmission in mice with chronic toxocariasis. BA...

Nontuberculous mycobacteria (NTM) causing human infectious disease have become increasingly common. Rapid and accurate identification to the species level is, therefore, critical. The Speed-Oligo® Mycobacteria assay is an oligochromatographic method that was made available recently for the identification and differentiation of mycobacteria. The pre...

Introducción. Los informes sobre Mycobacterium tuberculosis resistente a múltiples fármacos están aumentando a nivel mundial y los laboratorios toman cada vez más conciencia sobre la necesidad de realizar pruebas de sensibilidad a fármacos. Debido al tiempo prolongado que se requiere para hacerlas, se han propuesto nuevos enfoques para la detección...

The infectious disease Tuberculosis still causes many death around the world nowadays. The study of the bacillus that causes Tuberculosis, M. tuberculosis, is therefore very important. One special aspect to be studied is its growth. In this work we try a first attempt in estimating the parameters of a Multi-Agent-Based Simulation that can reproduce...

Mycobacterium bovis is the main causative agent of animal tuberculosis (TB) and it may cause TB in humans. Molecular typing of M. bovis isolates provides precise epidemiological data on issues of inter- or intra-herd transmission and wildlife reservoirs. Techniques used for typing M. bovis have evolved over the last 2 decades, and PCR-based methods...

Bovine tuberculosis is a major infectious disease of the cattle. In this study, 85 M. bovis isolates from 162 lymph nodes, obtained from a herd of cattle on a farm in southern Brazil, were evaluated using spoligotyping and VNTR. The strains were grouped into five clusters and five orphans, showing a heterogenic genetic profile, what could represent...

Mycobacterium bovis is the main causative agent of animal tuberculosis (TB) and it may cause TB in humans. Molecular typing of M. bovis isolates provides precise epidemiological data on issues of inter- or intra-herd transmission and wildlife reservoirs. Techniques used for typing M. bovis have evolved over the last 2 decades, and PCR-based methods...

Backgound and Objectives: This study is justified by the high TB prevalence in prisons, which constitutes a public health problem and aims to estimate the prevalence of active tuberculosis (TB) and determine the variables associated with respiratory symptoms in a prison in Brazil. Methods: This is a descriptive study of 262 inmates divided into res...

The increase in both opportunistic mycoses and antimicrobial resistance of pathogenic microorganisms has determined the need to develop new chemotherapies agents. Amazon Forest Plants has been used as natural drug by local people in the treatment of various tropical diseases. The objective of the study is to evaluate the antifungal activity of twen...

A sublineage of Mycobacterium tuberculosis called RD(Rio) was described in 2007. Although only recently described, this strain may have been present previously in the population, and its identification in clinical isolates will elucidate bacterial transmission dynamics and host-pathogen interactions. This study evaluated the clonal diversity of the...

Interaction between the anti-tuberculosis drug isoniazid (INH) and phosphatidylcholine membranes was investigated in terms of: (i) drug affinity to a lipid bilayer and (ii) drug-induced changes in the dynamic properties of liposomes, such as membrane hydration state, polar head and non-polar acyl chain order and lipid phase transition behavior. The...

This work describes the synthesis of a series of fatty acid hydrazide derivatives of isoniazid (INH). The compounds were tested against Mycobacterium tuberculosis H37Rv (ATCC 27294) as well as INH-resistant (ATCC 35822 and 1896 HF) and rifampicin-resistant (ATCC 35338) M. tuberculosis strains. The fatty acid derivatives of INH showed high antimycob...

Background / Purpose: To investigate the relationship between fitness and drug resistance. Main conclusion: Heterogeneity in fitness is a function of the drug resistance mutations and the strain genetic background.

Several medicinal plants are traditionally traded in open-air markets in Rio de Janeiro State (Brazil) to treat tuberculosis (TB) and related symptoms. Conduct a survey in the open-air markets of 20 cities of Rio de Janeiro State to find medicinal plants that are popularly used to treat tuberculosis and other related diseases and assess their in vi...

Tuberculosis is an infectious disease that still causes many deaths around the world nowadays. It is caused by the M. tuberculosis bacillus. The study of the growth curve of this infectious organism is relevant as it has wide applications in tuberculosis research. In this work a Multi-Agent-Based Simulation is proposed to pursue the reproduction in...

Spoligotyping has shown Mycobacterium tuberculosis strains to be composed of different lineages, and some of them are not just geographically restricted but also affect specific ethnic populations and are associated with outbreaks and drug resistance. We recently described a particular subtype within the Latin American-Mediterranean (LAM) family, c...

Introduction: Helicobacter pylori infection is associated with gastro-duodenal diseases. Genes related to pathogenicity have been described for H. pylori and some of them appear to be associated with more severe clinical outcomes of the infection. The present study investigates the role of cagE as a pathogenicity biomarker of H. pylori compare it...

Duroia macrophylla popularly known as "cabeça-de-urubú," "apuruí," or "puruí-grande-da-mata" occurs in the Amazon Forest. Its leaves and branches were collected twice and extracted with dichloromethane and methanol. All extracts were subjected to phytochemical investigation and terpenes and flavonoids were found in all dichloromethane and methanol...

Tuberculosis (TB) is one infectious disease responsible for more than 2 million of deaths worldwide. The increase of TB cases resistant to drugs normally used in treatment has reinforced the necessity of development of new antimicrobials, which should be active to resistant strains and latent bacilli, further it should reduce the treatment duration...