High frequency of multidrug-resistant Escherichia coli from cattle in the Cerrado and Pantanal biomes of Brazil.

The indiscriminate use of antimicrobials has led to the emergence of resistant bacteria, especially pathogenic strains of Escherichia coli, which are associated with diseases in animals and humans. The aim of the present study was to characterize E. coli isolates in calves with regards to the presence of virulence genes and investigate the resistance of the isolates to different antimicrobials. Between 2021 and 2023, 456 fecal samples were collected from calves in the Pantanal and Cerrado biomes of the state of Mato Grosso do Sul, Brazil. All samples were subjected to microbiological analysis and disc diffusion antibiogram testing. The polymerase chain reaction method was used to detect virulence genes. Bacterial growth was found in 451 of the 456 samples and biochemically identified as Escherichia coli. All 451 isolates (100%) exhibited some phenotypic resistance to antimicrobials and 67.62% exhibited multidrug resistance. The frequency of multidrug-resistant isolates in the Cerrado biome was significantly higher than that in the Pantanal biome (p = 0.0001). In the Cerrado, the most common pathotype was Shiga toxin-producing Escherichia coli (STEC) (28%), followed by toxigenic Escherichia coli (ETEC) (11%), enterohemorrhagic Escherichia coli (EHEC) (8%) and enteropathogenic Escherichia coli (EPEC) (2%). In most cases, the concomitant occurrence of pathotypes was more common, the most frequent of which were ETEC + STEC (33%), ETEC + EHEC (15%) and ETEC + EPEC (3%). The STEC pathotype (30%) was also found more frequently in the Pantanal, followed by EHEC (12%), ETEC (9%) and EPEC (6%). The STEC pathotype had a significantly higher frequency of multidrug resistance (p = 0.0486) compared to the other pathotypes identified. The frequency of resistance was lower in strains from the Pantanal biome compared to those from the Cerrado biome. Although some factors are discussed in this paper, it is necessary to clarify the reasons for this difference and the possible impacts of these findings on both animal and human health in the region.

Biochar as a carbonaceous material to enhance soil quality in drylands ecosystems: A review.

Drylands are fragile environments that should be carefully managed to improve their quality and functions to achieve sustainable development. Their major problems involve low availability of nutrients and soil organic carbon content. Biochar effect on soil is a joint response of micro to nano sized biochar and soil characteristics. In this review, we attempt to carry out a critical analysis of biochar application to enhance dryland soil quality. Correlating the effects identified from its soil application, we explored the subjects that remains open in the literature. The relation of composition-structure-properties of biochar vary among pyrolysis parameters and biomass sources. Limitations in soil physical quality in drylands, such as low water-holding capacity, can be alleviated by applying biochar at a rate of 10 Mg ha-1 also resulting in beneficial effects on soil aggregation, improved soil porosity, and reduced bulk density. Biochar addition can contribute to the rehabilitation of saline soils, by releasing cations able to displaces sodium in the exchange complex. However, the recovery process of salt-affected soils might be accelerated by the association of biochar with another soil conditioners. This is a promising strategy especially considering the biochar alkalinity and variability in nutrients bioavailability to improve soil fertilization. Further, while higher biochar application rate (>20 Mg ha-1) might change soil C dynamics, a combination of biochar and nitrogen fertilizer can increase microbial biomass carbon in dryland systems. Other aspect of biochar soil application is the economic viability of scale-up production, which is mainly associate to pyrolysis process being biochar production the costliest stage. Nevertheless, the supplying of feedstock might also represent a great input on biochar final costs. Therefore, biochar-based technology is a big opportunity to improve fragile environments such as drylands, integrating sustainable technologies with regional development. Considering the specificity of application area, it might be a model of sustainable agricultural practices protecting the environment in a bioeconomic perspective.

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs / Detecção de enteropatógenos e pesquisa de resíduos de agrotóxicos em Lactuca sativa de feiras tradicionais e agroecológicas

Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienicsanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoas is required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

A produção agroecológica representa uma nova realidade no cultivo das hortaliças. Assim, o estudo teve como objetivo verificar a presença de agrotóxicos em amostras agroecológicas e analisar a contaminação microbiológico e parasitológico em Lactuca sativa L. de feiras agroecológicas e convencionais de Alagoas. Foram coletadas 32 amostras, realizando checklist higiênico-sanitário, análises de coliformes, Salmonella spp., Staphylococcus aureus e Cromatografia Gasosa com Espectrômetro de Massas (GC-MS) para pesquisa de agrotóxicos; utilizando-se duas metodologias para estudos parasitológicos. Foram analisadas 32 amostras, com nível de adequação sanitária de 45% e 38% para feiras (agroecológicas e convencionais) respectivamente, sendo três amostras no total (9,4%) adequadas a padrão microbiológico segundo RDC n° 12//2001; Dentre as 23 amostras positivas para parasitos, 69,5% teve origem em amostras de feiras convencionais, e 53% de todas as amostras positivas apresentaram Entamoeba coli como principal contaminante, juntamente, não foi detectado traços de deltametrina, porem foi visualizado em duas amostras, pico de retenção para padrão de difenoconazol. Concluindo-se que as feiras representam um ambiente adequado para patógenos humanos e indicadores, necessitando de uma maior higienização e treinamento dos comerciantes e consumidores de hortaliças do estado de Alagoas, principalmente em feiras convencionais, que apresentaram índices microbiológicos e parasitológicos mais críticos em relação a feiras com produtos agroecológicos; mas, a presença de difenoconazole em duas amostras de feiras agroecológicas sugerem contaminação acidental ou uso indiscriminado deste químico em produção da Lactuca sativa L., todavia os produtos de origem agroecológica representam uma melhor escolha para o consumidor.

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs / Detecção de enteropatógenos e pesquisa de resíduos de agrotóxicos em Lactuca sativa de feiras tradicionais e agroecológicas

Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienic sanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoa sis required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

A produção agroecológica representa uma nova realidade no cultivo das hortaliças. Assim, o estudo teve como objetivo verificar a presença de agrotóxicos em amostras agroecológicas e analisar a contaminação microbiológico e parasitológico em Lactuca sativa L. de feiras agroecológicas e convencionais de Alagoas. Foram coletadas 32 amostras, realizando checklist higiênico-sanitário, análises de coliformes, Salmonella spp., Staphylococcus aureus e Cromatografia Gasosa com Espectrômetro de Massas (GC-MS) para pesquisa de agrotóxicos; utilizando-se duas metodologias para estudos parasitológicos. Foram analisadas 32 amostras, com nível de adequação sanitária de 45% e 38% para feiras (agroecológicas e convencionais) respectivamente, sendo três amostras no total (9,4%) adequadas a padrão microbiológico segundo RDC n° 12//2001; Dentre as 23 amostras positivas para parasitos, 69,5% teve origem em amostras de feiras convencionais, e 53% de todas as amostras positivas apresentaram Entamoeba coli como principal contaminante, juntamente, não foi detectado traços de deltametrina, porem foi visualizado em duas amostras, pico de retenção para padrão de difenoconazol. Concluindo-se que as feiras representam um ambiente adequado para patógenos humanos e indicadores, necessitando de uma maior higienização e treinamento dos comerciantes e consumidores de hortaliças do estado de Alagoas, principalmente em feiras convencionais, que apresentaram índices microbiológicos e parasitológicos mais críticos em relação a feiras com produtos agroecológicos; mas, a presença de difenoconazole em duas amostras de feiras agroecológicas sugerem contaminação acidental ou uso indiscriminado deste químico em produção da Lactuca sativa L., todavia os produtos de origem agroecológica representam uma melhor escolha para o consumidor.

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs

Abstract Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienic-sanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoas is required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

Resumo A produção agroecológica representa uma nova realidade no cultivo das hortaliças. Assim, o estudo teve como objetivo verificar a presença de agrotóxicos em amostras agroecológicas e analisar a contaminação microbiológico e parasitológico em Lactuca sativa L. de feiras agroecológicas e convencionais de Alagoas. Foram coletadas 32 amostras, realizando checklist higiênico-sanitário, análises de coliformes, Salmonella spp., Staphylococcus aureus e Cromatografia Gasosa com Espectrômetro de Massas (GC-MS) para pesquisa de agrotóxicos; utilizando-se duas metodologias para estudos parasitológicos. Foram analisadas 32 amostras, com nível de adequação sanitária de 45% e 38% para feiras (agroecológicas e convencionais) respectivamente, sendo três amostras no total (9,4%) adequadas a padrão microbiológico segundo RDC n° 12//2001; Dentre as 23 amostras positivas para parasitos, 69,5% teve origem em amostras de feiras convencionais, e 53% de todas as amostras positivas apresentaram Entamoeba coli como principal contaminante, juntamente, não foi detectado traços de deltametrina, porem foi visualizado em duas amostras, pico de retenção para padrão de difenoconazol. Concluindo-se que as feiras representam um ambiente adequado para patógenos humanos e indicadores, necessitando de uma maior higienização e treinamento dos comerciantes e consumidores de hortaliças do estado de Alagoas, principalmente em feiras convencionais, que apresentaram índices microbiológicos e parasitológicos mais críticos em relação a feiras com produtos agroecológicos; mas, a presença de difenoconazole em duas amostras de feiras agroecológicas sugerem contaminação acidental ou uso indiscriminado deste químico em produção da Lactuca sativa L., todavia os produtos de origem agroecológica representam uma melhor escolha para o consumidor.

High genetic diversity of hepatitis E virus in swine in São Paulo State, Brazil / Diversidade genética do vírus da hepatite E em suínos no estado de São Paulo, Brasil

A hepatite E é uma zoonose emergente que afeta diversas espécies de mamíferos, inclusive o ser humano. É ocasionada por um vírus da espécie Orthohepevirus A que possui diversos genótipos e subgenótipos. No Brasil é descrito o genótipo HEV-3, cujo principal reservatório é o porco doméstico. Testes moleculares e sorológicos demonstram o HEV-3 em diferentes estados, tanto em animais quanto em humanos. No estado de São Paulo, existem diversos estudos sobre a epidemiologia da hepatite E em humanos, mas faltam informações sobre o HEV-3 em suínos. Assim, o objetivo deste trabalho foi verificar a ocorrência de HEV por meio da técnica de RT-PCR e posterior sequenciamento em um banco de amostras de fezes de suínos colhidas entre 2008 e 2009, na região metropolitana de Campinas. Das 89 amostras analisadas, foi possível detectar o HEV-3 em sete e, pela reconstrução filogenética, foram encontrados os subgenótipos HEV-3b, HEV-3h, e HEV-3j. Uma amostra disponível no GenBank, proveniente de São Paulo, que ainda não havia sido subgenotipada, foi agrupada ao HEV-3i. Os subgenótipos HEV-3j e HEV-3i ainda não tinham sido relatados no país. O estudo demonstra uma grande diversidade genética do HEV no estado de São Paulo e reforça o caráter zoonótico da HEV-3.(AU)

Detection of enteropathogens and research of pesticide residues in Lactuca sativa from traditional and agroecological fairs.

Agroecological production represents a new reality in vegetable farming. Thus, the study aimed to search for the presence of pesticides in agroecological samples and microbiological and parasitological contamination in Lactuca sativa L. of agroecological and conventional fairs in Alagoas. Thirty-two samples were collected, a hygienic-sanitary checklist was performed, along with coliform, Salmonella spp., Staphylococcus aureus research and Gas Chromatography with Mass Spectrometer (GC-MS) for pesticide research; using two methodologies for parasitological studies. Thirty-two samples were analyzed, with a sanitary adequacy level at 45% and 38% for fairs (agroecological and conventional) respectively, with three samples (9.4%) in total, being adequate to the microbiological pattern according to RDC no. 12/2001. Among the 23 samples which were tested positive for parasites, 69.5% originated from samples extracted at conventional fairs, and 53% of every positive samples presented Entamoeba coli as the main contaminant. All together, no traces of deltamethrin were detected, but in two of the samples a peak retention for diphenoconazole was detected. In conclusion, the fairs represent an adequate environment for human pathogens and indicators. Therefore greater hygiene training of vegetable traders and consumers in the state of Alagoas is required, especially in conventional fairs, which presented more critical microbiological and parasitological indexes comparing to fairs with agroecological products; however, the presence of difenoconazole in two samples of agricultural fairs suggests accidental contamination or indiscriminate use of this chemical in the production of Lactuca sativa, however, products with agroecological origin represents a better choice for the consumers.

Identification of a novel protein in the genome sequences of Leptospira interrogans with the ability to interact with host's components.

BACKGROUND: Leptospirosis is an infectious disease that affects humans and animals worldwide. The etiological agents of this disease are the pathogenic species of the genus Leptospira. The mechanisms involved in the leptospiral pathogenesis are not full understood. The elucidation of novel mediators of host-pathogen interaction is important in the detection of virulence factors involved in the pathogenesis of leptospirosis. OBJECTIVE: This work focused on identification and characterization of a hypothetical protein of Leptospira encoded by the gene LIC10920. METHODS: The protein of unknown function was predicted to be surface exposed. Therefore, the LIC10920 gene was cloned and the protein expressed in Escherichia coli BL21 (DE3) Star pLysS strain. The recombinant protein was purified by metal affinity chromatography and evaluated with leptospirosis human serum samples. The interaction with host components was also performed. RESULTS: The recombinant protein was recognized by antibodies present in leptopsirosis human serum, suggesting its expression during infection. Immunofluorescence and intact bacteria assays indicated that the bacterial protein is surface-exposed. The recombinant protein interacted with human laminin, in a dose-dependent and saturable manner and was named Lsa24.9, for Leptospiral surface adhesin, followed by its molecular mass. Lsa24.9 also binds plasminogen (PLG) in a dose-dependent and saturable fashion, fulfilling receptor ligand interaction. Moreover, Lsa24.9 has the ability to acquire PLG from normal human serum, exhibiting similar profile as observed with the human purified component. PLG bound Lsa24.9 was able of generating plasmin, which could increase the proteolytic power of the bacteria. CONCLUSIONS: This novel leptospiral protein may function as an adhesin at the colonization steps and may help the invasion process by plasmin generation at the bacterial cell surface.

Identification of a novel protein in the genome sequences of Leptospira interrogans with the ability to interact with host's components

Background Leptospirosis is an infectious disease that affects humans and animals worldwide. The etiological agents of this disease are the pathogenic species of the genus Leptospira. The mechanisms involved in the leptospiral pathogenesis are not full understood. The elucidation of novel mediators of host-pathogen interaction is important in the detection of virulence factors involved in the pathogenesis of leptospirosis. Objective This work focused on identification and characterization of a hypothetical protein of Leptospira encoded by the gene LIC10920. Methods The protein of unknown function was predicted to be surface exposed. Therefore, the LIC10920 gene was cloned and the protein expressed in Escherichia coli BL21 (DE3) Star pLysS strain. The recombinant protein was purified by metal affinity chromatography and evaluated with leptospirosis human serum samples. The interaction with host components was also performed. Results The recombinant protein was recognized by antibodies present in leptopsirosis human serum, suggesting its expression during infection. Immunofluorescence and intact bacteria assays indicated that the bacterial protein is surface-exposed. The recombinant protein interacted with human laminin, in a dose-dependent and saturable manner and was named Lsa24.9, for Leptospiral surface adhesin, followed by its molecular mass. Lsa24.9 also binds plasminogen (PLG) in a dose-dependent and saturable fashion, fulfilling receptor ligand interaction. Moreover, Lsa24.9 has the ability to acquire PLG from normal human serum, exhibiting similar profile as observed with the human purified component. PLG bound Lsa24.9 was able of generating plasmin, which could increase the proteolytic power of the bacteria. Conclusions This novel leptospiral protein may function as an adhesin at the colonization steps and may help the invasion process by plasmin generation at the bacterial cell surface.

Identification of a novel protein in the genome sequences of Leptospira interrogans with the ability to interact with host's components

Background Leptospirosis is an infectious disease that affects humans and animals worldwide. The etiological agents of this disease are the pathogenic species of the genus Leptospira. The mechanisms involved in the leptospiral pathogenesis are not full understood. The elucidation of novel mediators of host-pathogen interaction is important in the detection of virulence factors involved in the pathogenesis of leptospirosis. Objective This work focused on identification and characterization of a hypothetical protein of Leptospira encoded by the gene LIC10920. Methods The protein of unknown function was predicted to be surface exposed. Therefore, the LIC10920 gene was cloned and the protein expressed in Escherichia coli BL21 (DE3) Star pLysS strain. The recombinant protein was purified by metal affinity chromatography and evaluated with leptospirosis human serum samples. The interaction with host components was also performed. Results The recombinant protein was recognized by antibodies present in leptopsirosis human serum, suggesting its expression during infection. Immunofluorescence and intact bacteria assays indicated that the bacterial protein is surface-exposed. The recombinant protein interacted with human laminin, in a dose-dependent and saturable manner and was named Lsa24.9, for Leptospiral surface adhesin, followed by its molecular mass. Lsa24.9 also binds plasminogen (PLG) in a dose-dependent and saturable fashion, fulfilling receptor ligand interaction. Moreover, Lsa24.9 has the ability to acquire PLG from normal human serum, exhibiting similar profile as observed with the human purified component. PLG bound Lsa24.9 was able of generating plasmin, which could increase the proteolytic power of the bacteria. Conclusions This novel leptospiral protein may function as an adhesin at the colonization steps and may help the invasion process by plasmin generation at the bacterial cell surface.

Evaluation of antibodies against Toxoplasma gondii and Leptospira spp. in Magellanic penguins (Spheniscus magellanicus) on Magdalena Island, Chile.

Toxoplasmosis has been reported in many avian species, but little information is available from wild penguin populations. Leptospira can infects domestic and wild animals. Spheniscus magellanicus belong to the order Sphenisciformes, family Spheniscidae, and are colonial birds. These seabirds live in temperate waters along the Atlantic shores of South America, and their total population has been estimated to be 1,300,000 breeding pairs. Magdalena Island (Chile) hosts an important breeding colony but, over recent decades, a marked decline in the number of birds has been seen. The objective of this study was to determine occurrences of antibodies against T. gondii and Leptospira spp. in penguins (Spheniscus magellanicus) on Magdalena Island, from where no previous data on these agents were available. Serum samples were collected from 132 penguins on Magdalena Island. Antibodies against Toxoplasma gondii were detected using the modified agglutination test (Titer ≥20), and anti-Leptospira spp. antibodies were detected using the microscopic agglutination test (Titer ≥100). T. gondii antibodies were detected in 57 (43.18%) of the 132 serum samples, with titers that ranged from 20 to 320. None of the penguins in this study was reactive to anti-Leptospira spp. antibodies. This is the first report of T. gondii seropositivity in free-living Magellanic penguins in Chile.

Biaxial Strain Transfer in Supported Graphene.

Understanding the mechanism and limits of strain transfer between supported 2D systems and their substrate is a most needed step toward the development of strain engineering at the nanoscale. This includes applications in straintronics, nanoelectromechanical devices, or new nanocomposites. Here, we have studied the limits of biaxial compressive strain transfer among SiO2, diamond, and sapphire substrates and graphene. Using high pressure-which allows maximizing the adhesion between graphene and the substrate on which it is deposited-we show that the relevant parameter governing the graphene mechanical response is not the applied pressure but rather the strain that is transmitted from the substrate. Under these experimental conditions, we also show the existence of a critical biaxial stress beyond which strain transfer become partial and introduce a parameter, α, to characterize strain transfer efficiency. The critical stress and α appear to be dependent on the nature of the substrate. Under ideal biaxial strain transfer conditions, the phonon Raman G-band dependence with strain appears to be linear with a slope of -60 ± 3 cm-1/% down to biaxial strains of -0.9%. This evolution appears to be general for both biaxial compression and tension for different experimental setups, at least in the biaxial strain range -0.9% < ε < 1.8%, thus providing a criterion to validate total biaxial strain transfer hypotheses. These results invite us to cast a new look at mechanical strain experiments on deposited graphene as well as to other 2D layered materials.

Pre-Multidrug-Resistant Mycobacterium tuberculosis Infection Causing Fatal Enteric Disease in a Dog from a Family with History of Human Tuberculosis.

This report describes a fatal case of a pet dog with major enteric signs owned by a family that has experienced cases of pulmonary tuberculosis (TB) in the household. Clinical and epidemiological aspects, imaging data, microbiological, haematological and histopathological examinations were assessed to diagnosis of disease. gyrB-RFLP, spoligotyping and MIRU-VNTR allowed molecular detection of M. tuberculosis strain from S family. The resazurin microtiter assay indicated that all isolates were resistant to isoniazid, ethambutol, ciprofloxacin, ofloxacin, streptomycin and amikacin. The public health concerns related to canine tuberculosis and risk of the dissemination by pets of M. tuberculosis pre-multidrug-resistant (PMD) to isoniazid, ethambutol and other first-line drugs used in human therapy of TB are discussed. We believe this to be the first report of PMD M. tuberculosis infection in a dog presenting mainly enteric manifestation, confirmed as S lineage by molecular methods, owned by a family in which TB has spread in the household for generations.

Defect characterization in graphene and carbon nanotubes using Raman spectroscopy.

This review discusses advances that have been made in the study of defect-induced double-resonance processes in nanographite, graphene and carbon nanotubes, mostly coming from combining Raman spectroscopic experiments with microscopy studies and from the development of new theoretical models. The disorder-induced peak frequencies and intensities are discussed, with particular emphasis given to how the disorder-induced features evolve with increasing amounts of disorder. We address here two systems, ion-bombarded graphene and nanographite, where disorder is represented by point defects and boundaries, respectively. Raman spectroscopy is used to study the 'atomic structure' of the defect, making it possible, for example, to distinguish between zigzag and armchair edges, based on selection rules of phonon scattering. Finally, a different concept is discussed, involving the effect that defects have on the lineshape of Raman-allowed peaks, owing to local electron and phonon energy renormalization. Such effects can be observed by near-field optical measurements on the G' feature for doped single-walled carbon nanotubes.

Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent.

In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

Synthesis and characterization of selenium-carbon nanocables.

In this letter, we report the synthesis and characterization of a novel Se-C hybrid nanostructure. X-ray diffraction data indicates a high degree of crystallinity for the nanostructured Se shell. High resolution transmission electron microscopy images show that the Se-C nanostructures consist of coaxial nanocables made of single wall carbon nanotubes, as the core, surrounded by a trigonal Selenium shell. Resonance Raman spectroscopy was used to access the properties of both the carbon nanotubes and selenium. The behavior of the radial breathing mode and the G-band indicates that the Se shell primarily covers semiconducting nanotubes. X-ray photoelectron spectroscopy show that the nanocables have a thin coverage of selenium oxide. We envisage that this system could be used in the fabrication of photonic devices as an interface between electronic and photonic materials.

Strain-induced interference effects on the resonance Raman cross section of carbon nanotubes.

In this Letter, we report the effects of strain on the electronic properties of single-wall carbon nanotubes. When we normalize the electronic transition energies to the corresponding values obtained for unstrained tubes, we obtain that, regardless of the tube diameter, all the data collapse onto universal curves following an n - m = constant family pattern. In the case of metallic tubes, quantum interference effects on the Raman cross section are predicted for strained tubes when the energies of the lower and the upper components have nearly the same values. Experimental evidence for the strain-induced Raman cross section changes is observed in single nanotube spectroscopy.

Genetic characterization of Chromobacterium isolates from black water environments in the Brazilian Amazon.

AIMS: To isolate and to characterize the diversity of Chromobacterium violaceum from the Brazilian Amazon region. METHODS AND RESULTS: Twenty-two isolates were obtained from the waters and banks of the river Negro, in the Brazilian Amazon. All isolates were able to grow in vitro at 44 degrees C and pH 4.0, but were adversely affected by temperatures below 15 degrees C, and unable to survive at 4 degrees C, properties that may be related to the adaptation to the ecosystem. The isolates were joined at a final level of similarity of only 13% in the rep-PCR analysis. The analysis of 16S rRNA genes resulted in three main groups clustered at a final level of similarity of 97% and only three isolates were clustered with the type strain. Similar data were obtained for the 23S rRNA gene. CONCLUSIONS: A high level of genetic diversity was verified with indications that the Brazilian isolates would fit into at least two new clusters besides C. violaceum species. SIGNIFICANCE AND IMPACT OF THE STUDY: The results show remarkable bacterial adaptability and genetic diversity of C. violaceum in the Amazon region.

One-dimensional character of combination modes in the resonance Raman scattering of carbon nanotubes.

Resonance Raman spectroscopy with an energy tunable system is used to analyze the 600-1100 cm(-1) spectral region in single-wall carbon nanotubes. Sharp peaks are associated with the combination of zone folded optic and acoustic branches from 2D graphite. These combination modes exhibit a peculiar dependence on the excitation laser energy that is explained on the basis of a highly selective resonance process that considers phonons and electrons in low dimensional materials.