146 research outputs found
Paracoccidioides brasiliensis pancreatic destruction in Calomys callosus experimentally infected
<p>Abstract</p> <p>Background</p> <p>The wild rodent <it>Calomys callosus </it>is notably resistant to <it>Trypanosoma cruzi </it>infection. In order to better characterize this animal model for experimental infections, we inoculated <it>C</it>. <it>callosus </it>intraperitoneally with <it>Paracoccidioides brasiliensis</it>, a thermally dimorphic fungus that causes a chronic disease with severe granuloma formation in the mouse and humans. The dissemination of <it>P. brasiliensis </it>cells through the lungs, liver, pancreas, and spleen was assessed by histological analysis.</p> <p>Results</p> <p>The animals were susceptible to infection and showed a granulomatous reaction. <it>C. callosus </it>presented peritonitis characterized by the presence of exudates containing a large number of yeast cells. Extensive accumulation of yeast cells with intense destruction of the parenchyma was observed in the pancreas, which reduced the glucose levels of infected animals. These lesions were regressive in the liver, spleen, and lungs until complete recovery. The role of estrogen during <it>C. callosus </it>infection with <it>P. brasiliensis </it>was addressed by infecting ovariectomized animals. It was observed a reduced inflammatory response as well as reduced extension of tissue damage. Removal of ovaries reestablished the normal glucose levels during infection.</p> <p>Conclusion</p> <p>Taken together, the results presented here reveal the pancreas as being an important organ for the persistence of <it>P. brasiliensis </it>during infection of <it>C. callosus </it>and that estrogen plays an important role in the susceptibility of the animals to this pathogen.</p
In Vitro Antimicrobial Susceptibility of Mycobacterium massiliense Recovered from Wound Samples of Patients Submitted to Arthroscopic and Laparoscopic Surgeries
Testing of rapidly growing species of mycobacteria (RGM) against antibacterial agents has been shown to have some clinical utility. This work establishes the MICs of seven antimicrobial agents following the guidelines set forth by the Clinical and Laboratory Standards Institute (CLSI) against eighteen isolates of Mycobacterium massiliense recovered from wound samples of patients submitted to minimally invasive surgery such as arthroscopy and laparoscopy. The isolates showed susceptibility to amikacin (MIC90 = 4 μg/mL) and clarithromycin (MIC90 < 1 μg/mL) but resistance to ciprofloxacin (MIC90 > 16 μg/mL), doxycycline (MIC90 > 32 μg/mL), sulfamethoxazole (MIC90 > 128 μg/mL), and tobramycin (MIC90 = 32 μg/mL), and intermediate profile to cefoxitin (MIC90 = 64 μg/mL). Therefore, we suggest that the antimicrobial susceptibilities of any clinically significant RGM isolate should be performed
The activity of a Hexameric M17 Metallo-Aminopeptidase is associated with survival of Mycobacterium tuberculosis
Mycobacterium tuberculosis is one of the most prevalent human pathogens causing millions of deaths in the last years. Moreover, tuberculosis (TB) treatment has become increasingly challenging owing to the emergence of multidrug resistant M. tuberculosis strains. Thus, there is an immediate need for the development of new anti-TB drugs. Proteases appear to be a promising approach and may lead to shortened and effective treatments for drug-resistant TB. Although the M. tuberculosis genome predicts more than 100 genes encoding proteases, only a few of them have been studied. Aminopeptidases constitute a set of proteases that selectively remove amino acids from the N-terminus of proteins and peptides and may act as virulence factors, essential for survival and maintenance of many microbial pathogens. Here, we characterized a leucine aminopeptidase of M. tuberculosis (MtLAP) as a cytosolic oligomeric metalloaminopeptidase. Molecular and enzymatic properties lead us to classify MtLAP as a typical member of the peptidase family M17. Furthermore, the aminopeptidase inhibitor bestatin strongly inhibited MtLAP activity, in vitro M. tuberculosis growth and macrophage infection. In murine model of TB, bestatin treatment reduced bacterial burden and lesion in the lungs of infected mice. Thus, our data suggest that MtLAP participates in important metabolic pathways of M. tuberculosis necessary for its survival and virulence and consequently may be a promising target for new anti-TB drugs
New vectors derived from pUC18 for cloning and thermal-induced expression in Escherichia coli
We report the construction of two vectors for Escherichia coli: pUC72, for molecular cloning, and pPLT7,
for thermal-induced expression. The main feature of pUC72 is a novel polylinker region that includes
restriction sites for Nde I and Nco I which provide an ATG codon for proper translation initiation of
expressed genes. Vector pPLT7 is ideal for thermo-inducible expression in host cells that carry the cI857
repressor gene. The use of pPLT7 was validated by the successful expression of the genes encoding carp
and porcine growth hormones. These vectors provide novel cloning possibilities in addition to simple,
non-expensive, high level expression of recombinant proteins in E. coli
Non-disulfide-Bridge peptide 5.5 from the Scorpion Hadrurus gertschi Inhibits the growth of mycobacterium abscessus subsp. massiliense
Multi-drug resistant microorganisms have been a growing concern during the last decades due to their contribution in mortality rates worldwide. Antimicrobial peptides (AMPs) are broad spectrum antimicrobial agents that display potent microbicidal activity against a wide range of microorganisms. AMPs generally have a rapid mode of action that reduces the risk of resistance developing among pathogens. In this study, an AMP derived from scorpion venom, NDBP-5.5, was evaluated against Mycobacterium abscessus subsp. massiliense, a rapidly growing and emerging pathogen associated with healthcare infections. The minimal bactericidal concentration of NDBP-5.5, AMP quantity necessary to stop bacteria visible growth, against M. abscessus subsp. massiliense was 200 μM, a concentration that did not induce hemolysis of human red blood cells. The therapeutic index was 3.05 indicating a drug with low toxicity and therefore good clinical potential. Treatment of infected macrophages with NDBP-5.5 or clarithromycin presented similar results, reducing the bacterial load. M. abscessus subsp. massiliense-infected animals showed a decrease in the bacterial load of up to 70% when treated with NDBP-5.5. These results revealed the effective microbicidal activity of NDBP-5.5 against Mycobacterium, indicating its potential as an antimycobacterial agent
Microbiological quality of human milk from a Brazilian milk bank
OBJECTIVE: The objectives of the present study were to determine the prevalence of potentially pathogenic microorganisms that indicate the hygienic and sanitary conditions of human milk samples collected at a Human Milk Bank. METHODS: Three hundred and thirty eight (338) samples of human milk collected from a milk bank in a maternity in the municipality of Goiânia, in the state of Goias, Brazil were submitted to microbiological analysis. The latter were plated on McConkey agar according to the type of bacteria. Among the total number of samples collected, 194 consisted of raw milk and the remaining 144 were pasteurized milk. RESULTS: The presence of Staphylococcus spp., Streptococcus spp., yeasts and molds, and Enterobacteriaceae was verified in the raw milk samples. Staphylococcus aureus were isolated in 10 (5.2%) samples, Staphylococcus epidermidis in 28 (14.4%) samples, Streptococcus spp. in three (1.6%) samples, yeasts and molds in 43 (22.2%) and Enterobacteriaceae in 49 (25.3%) samples. In a hundred and forty four (144) samples which underwent thermal treatment Staphylococcus aureus was detected in five (3.5%) samples, Staphylococcus epidermidis in 15 (10.4%), Staphylococcus lugdenensis in two (1.4%), Streptococcus spp. in four (2.8%), yeasts and molds in 37 (25.7%), and Enterobacteriaceae in nine (6.3%). CONCLUSIONS: Analysis indicated a high degree of contamination in raw human milk, and as for the pasteurized milk, despite elimination of the great majority of potentially pathogenic microorganisms, the percentage of yeasts and molds was higher than in raw milk, demonstrating that a lower degree of initial contamination would be necessary for pasteurization to be an efficient means of microbiological control.OBJETIVO: Determinar a prevalência de microrganismos indicadores e potencialmente patogênicos que indicam as condições higiênico-sanitárias das amostras de leite humano ordenhado coletadas em banco de leite. MÉTODOS: Foram realizadas análises microbiológicas de 338 amostras de leite humano ordenhado, sendo 194 de leite cru e 144, pasteurizado, coletadas em banco de leite humano de um hospital materno infantil de Goiânia, GO. As análises microbiológicas foram realizadas com semeadura em ágar Mc Conkey, de acordo com o tipo de bactéria. RESULTADOS: No leite cru, verificou-se a presença de Staphylococcus spp. Streptococcus spp., bolores e leveduras e Enterobacteriaceae. Observou-se que Staphylococcus aureus esteve presente em 10 (5,2%) amostras, Staphylococcus epidermidis em 28 (14,4%), Streptococcus spp. em três (1,6%), bolores e leveduras em 43 (22,2%) e Enterobacteriaceae em 49 (25,3%). Das 144 amostras de leite humano ordenhado pasteurizado, detectaram-se Staphylococcus aureus em cinco (3,5%), Staphylococcus epidermidis em 15 (10,4%), Staphylococcus lugdenensis em duas (1,4%), Streptococcus spp. em quatro (2,8%), bolores e leveduras em 37 (25,7%) e Enterobacteriaceae em nove (6,3%). CONCLUSÕES: Os resultados mostraram um alto grau de contaminação no leite cru. No leite pasteurizado, apesar da eliminação da grande maioria de microrganismos potencialmente patogênicos, a percentagem de bolores e leveduras excedeu a de leite cru, mostrando a necessidade de obtenção de um leite com carga microbiana inicial mais baixa para que a pasteurização seja eficiente no controle microbiológico
AVALIAÇÃO DE RESISTÊNCIA ASSOCIADA AO BIOFILME DE ISOLADOS DE Candida E IDENTIFICAÇÃO DE ESPÉCIES POR PCR EM TEMPO REAL
Introdução e objetivos: Espécies do gênero Candida são comensais endógenos em indivíduos saudáveis e infecçãocausada por esses agentes é denominada candidíase. Pacientes hospitalizados tempredisposição para adquirir candidíase invasiva apresentando isoladosresistentes aos antifúngicos em decorrência da formação de biofilme. Dessa forma, o objetivo dotrabalho foi avaliar o biofilme de isolados de Candida de pacientes hospitalizados diferenciando as espécies porPCR em tempo real. Metodologia: O ensaio de redução do sal tetrazólio foi utilizadopara determinar a suscetibilidade das células sésseis de 21 isolados de Candida frente à caspofungina,anfotericina B, fluconazol e voriconazol. Diferenciação das espécies foirealizada por comparação da temperatura de melting de amplicons da região doDNA ribossomal 18S. Resultadose discussões: Foramisolados 10 C. albicans, 10 C. parapsilosis e 01 C. tropicalis. As células sésseis foramresistentes em 71,4% dos isolados, apresentando sensibilidade apenas àanfotericina B. Foi possível diferenciar a Tm das espécies por análiseestatística (p<0,05). Conclusões: Os dados evidenciam a mudança no perfil epidemiológico com aumento nonúmero de espécies não albicans. Amaioria dos isolados apresentou resistência aos antifúngicos. Apesar dadiferenciação da Tm dos isolados pela PCR em tempo real, a região amplificadanão apresentou variação para distinção das espécies
Early Holocene ritual complexity in South America: the archaeological record of Lapa do Santo (east-central Brazil)
Early Archaic human skeletal remains found in a burial context in Lapa do Santo in eastcentral Brazil provide a rare glimpse into the lives of hunter-gatherer communities in South America, including their rituals for dealing with the dead. These included the reduction of the body by means of mutilation, defleshing, tooth removal, exposure to fire and possibly cannibalism, followed by the secondary burial of the remains according to strict rules. In a later period, pits were filled with disarticulated bones of a single individual without signs of body manipulation, demonstrating that the region was inhabited by dynamic groups in constant transformation over a period of centuries
Genomic history of coastal societies from eastern South America
Sambaqui (shellmound) societies are among the most intriguing archaeological phenomena in pre-colonial South America, extending from approximately 8,000 to 1,000 years before present (yr bp) across 3,000 km on the Atlantic coast. However, little is known about their connection to early Holocene hunter-gatherers, how this may have contributed to different historical pathways and the processes through which late Holocene ceramists came to rule the coast shortly before European contact. To contribute to our understanding of the population history of indigenous societies on the eastern coast of South America, we produced genome-wide data from 34 ancient individuals as early as 10,000 yr bp from four different regions in Brazil. Early Holocene hunter-gatherers were found to lack shared genetic drift among themselves and with later populations from eastern South America, suggesting that they derived from a common radiation and did not contribute substantially to later coastal groups. Our analyses show genetic heterogeneity among contemporaneous Sambaqui groups from the southeastern and southern Brazilian coast, contrary to the similarity expressed in the archaeological record. The complex history of intercultural contact between inland horticulturists and coastal populations becomes genetically evident during the final horizon of Sambaqui societies, from around 2,200 yr bp, corroborating evidence of cultural change
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