Abscesos cerebrales por Dermacoccus nishinomiyaensis como primera manifestación de enfermedad granulomatosa crónica / Dermacoccus nishinomiyaensis brain abscesses as the first manifestation of chronic granulomatous disease

La enfermedad granulomatosa crónica es una inmunodeficiencia primaria poco frecuente, que secaracteriza por defectos en alguna de las subunidades del complejo enzimático nicotinamida adeninadinucleótido fosfato oxidasa, que ocasiona un déficit en la generación de anión superóxido por losfagocitos. Dentro de este grupo, la forma ligada al X es la más frecuente. Se reporta el caso de una paciente de sexo femenino de 2 años con enfermedad granulomatosa crónica autosómica recesiva, con mutación en gen CYBA, quien presentó manifestación inicial de la enfermedad con abscesos cerebrales ocasionados por un germen oportunista (Dermacoccus nishinomiyaensis). Esta infección permitió la sospecha diagnóstica temprana, por lo que recibió el tratamiento y la profilaxis en forma oportuna. Actualmente, se encuentra libre de infecciones, a la espera del trasplante de células progenitoras hematopoyéticas.

Chronic granulomatous disease is a rare primary immunodeficiency characterized by defects in one of the subunits of the nicotinamide adenine dinucleotide phosphate oxidase enzyme complex, which causes a deficiency in the capacity of phagocytes to generate superoxide anion. Within this group, the X-linked form is the most frequent. Here we report the case of a 2-year-old female patient with autosomal recessive chronic granulomatous disease, with a mutation in the CYBA gene, whose initial manifestation was brain abscesses caused by an opportunistic microorganism (Dermacoccus nishinomiyaensis). The infection led to an early diagnostic suspicion, so treatment and prophylaxis were administered in a timely manner. Currently, she is infectionfree, awaiting hematopoietic progenitor cell transplantation.

Microbial evaluation of implant surface - a clinical study comparing submerged, non-submerged and immediately loaded implants

Aim: The aim of the present study was to evaluate the microbial contamination in internal and external walls of cone morse implant walls. Methods: Eleven patients with edentulous mandibular posterior area were selected to received dental implants, divided into groups: submerged (S), non-submerged (NS), and immediately loaded (IL). Microbiological evaluations (microorganisms' number, aerobic and anaerobic colony forming units (CFU) number and microorganisms' qualification) were divided into internal and external collection of the implant walls, at different stages: T0 (surgical procedure), T2 (suture removal), T4 (reopening S group), T6 (suture removal S group), and T8 (abutment placement in S and NS). All data were submitted to statistical analyses, with confidence level of 0.05. Results: There was difference in number of microorganisms observed over time within the same group (p < 0.05). A difference was observed in CFU when evaluated within the same group over time (p < 0.05), except for the IL group. In internal collection, a predominance of non-formation of microorganisms was observed at T0 in all groups, while formation of Gram-positive Diplococci and Gram-positive Bacilli was observed at T8 (p>0.05). In external collection, an increase in number of microorganisms was observed at T0. Conclusion: There was no difference in microbial contamination among the evaluated groups. The microorganism's colonization changed over time

Actividad antibacteriana de actinomicetos frente a Escherichia coli y Staphylococcus aureus multirresistentes de origen hospitalario / Antibacterial activity of actimycetes against multiresistant Escherichia coli and Staphylococcus aureus isolated from a hospital

Introducción: La resistencia a los antimicrobianos (RAM) es un problema de salud pública que manifiesta la disminuida eficacia de estos agentes en la prevención y tratamiento de una proporción cada vez más amplia de patologías. Los actinomicetos son un grupo bacteriano importante de productores de metabolitos activos contra patógenos. Objetivo: Aislar actinomicetos del bosque tropical de Nariño, con potencial producción de metabolitos inhibitorios contra bacterias multidrogo-resistentes. Materiales y métodos: Se tomaron muestras de suelo de Bosque Tropical Húmedo de la Reserva Natural del Río Ñambí, se analizaron microbiológica y molecularmente. Se estimuló la producción in vitro de metabolitos secundarios y evaluó el efecto inhibitorio de estos extractos contra las bacterias multidrogo-resistentes Escherichia coli y Staphylococcus aureus. Resultados: Se obtuvieron 11 aislados presuntivos, se confirmó que cuatro de ellos correspondieron al género Streptomyces sp. Las pruebas de inhibición contra bacterias multidrogo-resistentes E. coli y S. aureus, permitieron verificar que el aislado P3772 fue el más eficiente en la inhibición de los patógenos. Conclusiones: Todos los actinomicetos evaluados presentan actividad antibacteriana contra al menos una de las bacterias patógenas estudiadas; destacando el aislado P3772, que inhibe a E. coli y S. aureus. Se espera caracterizar los compuestos vinculados a la actividad antibacteriana.

Introduction: Antimicrobial resistance (AR) is a public health problem that reveals the diminished efficacy of these agents in the prevention and treatment of an increasingly larger number of pathologies. Actinomycetes are an important bacterial producer group of metabolites that are active against pathogens. Objective: To isolate actinomycetes from the tropical forest of Nariño (Colombia), which have the potential to produce inhibitory metabolites against multi-drug resistant bacteria. Materials and methods: Soil samples were taken from the Humid Tropical Forest of the Río Ńambí Natural Reserve and analyzed through microbiological and molecular assays. In vitro production of secondary metabolites was first stimulated, followed by the assessment of the inhibitory effect of these extracts against multi-drug resistant Escherichia coli and Staphylococcus aureus. Results: 11 presumptive isolates were obtained, confirming that four of them corresponded to the Streptomyces sp. genus. The bacterial isolate P3772 was identified as the one with the highest inhibitory effect against multi-drug resistant E. coli and S. aureus. Conclusions: All the actinomycetes evaluated presented antibacterial activity. The isolate P3772 stands out, which inhibited both E. coli and S. aureus. The compounds associated with this antibacterial activity will be characterized in future studies.

In-vitro model of scardovia wiggsiae biofilm formation and effect of nicotine

Abstract Recently, Scardovia wiggsiae has been reported to be strongly associated with caries formation. This study aimed to establish an in vitro model of S. wiggsiae biofilm and to investigate the effect of nicotine on S. wiggsiae colony-forming units (CFUs) growth. S. wiggsiae biofilm was grown overnight using brain-heart infusion (BHI) broth supplemented with 5 g of yeast extract/L (BHI-YE). The overnight culture was used as an inoculum to grow S. wiggsiae biofilm on standardized enamel and dentin samples. Samples were incubated with different nicotine concentrations (0, 0.5, 1, 2, 4, 8, 16 and 32 mg/mL) for 3 days. The dissociated biofilms were diluted, spiral plated on blood agar plates, and incubated for 24 h. CFUs/mL were quantified using an automated colony counter. A two-way ANOVA was used to compare the effect of different nicotine concentrations on S. wiggsiae CFUs. This study demonstrated that S. wiggsiae biofilm could be initiated and formed in vitro. Increased CFUs was observed through 0.5-4 mg/mL and 0.5-8 mg/mL of nicotine using enamel and dentin substrates, respectively. 16 and 32 mg/mL of nicotine were determined as the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), respectively. S. wiggsiae formed greater biofilm on enamel than dentin specimens in response to the nicotine stimulus. This study demonstrated the negative effect of smoking on increasing S. wiggsiae biofilm. Establishing S. wiggsiae biofilm in vitro may allow researchers in the future to have a better understanding of caries pathogenesis and bacterial interaction.

Resumo Recentemente, foi relatado que Scardovia wiggsiae está fortemente associado à formação de cáries. Este estudo teve como objetivo estabelecer um modelo in vitro de biofilme de S. wiggsiae e investigar o efeito da nicotina no crescimento de unidades formadoras de colônias (UFC) de S. wiggsiae. O biofilme de S. wiggsiae foi cultivado durante a noite usando caldo de infusão de cérebro-coração (BHI) suplementado com 5 g de extrato de levedura / L (BHI-YE). A cultura noturna foi usada como um inóculo para cultivar biofilme de S. wiggsiae em amostras padronizadas de esmalte e dentina. As amostras foram incubadas com diferentes concentrações de nicotina (0, 0,5, 1, 2, 4, 8, 16 e 32 mg/mL) por 3 dias. Os biofilmes dissociados foram diluídos, semeados em espiral em placas de ágar sangue e incubados por 24 h. UFC/mL foram quantificados usando um contador de colônias automatizado. Uma ANOVA de duas vias foi usada para comparar o efeito de diferentes concentrações de nicotina em UFCs de S. wiggsiae. Este estudo demonstrou que o biofilme de S. wiggsiae pode ser iniciado e formado in vitro. UFCs aumentadas foram observadas com 0,5-4 mg/mL e 0,5-8 mg/mL de nicotina usando substratos de esmalte e dentina, respectivamente. A concentração inibitória mínima (CIM) e a concentração bactericida mínima (CBM) de nicotina foram determinadas, respectivamente, como 16 e 32 mg/mL. S. wiggsiae formou maior biofilme no esmalte do que espécimes de dentina em resposta ao estímulo de nicotina. Este estudo demonstrou o efeito negativo do tabagismo no aumento do biofilme de S. wiggsiae. O estabelecimento do biofilme de S. wiggsiae in vitro pode permitir que os pesquisadores no futuro tenham uma melhor compreensão da patogênese da cárie e da interação bacteriana.

Gene expression profile of Scardovia spp. in the metatranscriptome of root caries

Abstract A few investigations of caries biofilms have identified Scardovia spp.; however, little is known about its involvement in caries pathogenesis. The purpose of this study was to assess the gene expression profile of Scardovia spp. in root caries, and compare it with other microorganisms. Clinical samples from active root caries lesions were collected. Microbial mRNA was isolated and cDNA sequenced. The function and composition of the Scardovia were investigated using two methods: a) de novo assembly of the read data and mapping to contigs, and b) reads mapping to reference genomes. Pearson correlation was performed (p < 0.05). Proportion of Scardovia inopinata and Scardovia wiggsiae sequences ranged from 0-6% in the root caries metatranscriptome. There was a positive correlation between the transcriptome of Lactobacillus spp. and Scardovia spp. (r = 0.70; p = 0.03), as well as with other Bifidobacteriaceae (r = 0.91; p = 0.0006). Genes that code for fructose 6-phosphate phosphoketolase (the key enzyme for "Bifid shunt"), as well as ABC transporters and glycosyl-hydrolases were highly expressed. In conclusion, "Bifid shunt" and starch metabolism are involved in carbohydrate metabolism of S. inopinata and S. wiggsiae in root caries. There is a positive correlation between the metabolism abundance of Lactobacillus spp., Bifidobacteriaceae members, and Scardovia in root caries.

Endocarditis bacteriana por Kocuria kristinae en un paciente inmunocompetente. Reporte de caso / Bacterial endocarditis by Kocuria kristinae in an immunocompetent patient. Case report

Los miembros del género Kocuria corresponden a cocos Gram positivos ubicuos, generalmente inocuos y que hacen parte de la flora saprófita de un porcentaje importante de la población; ocasionalmente han sido descritos como los agentes responsables de patologías infecciosas, principalmente dentro del contexto de pacientes que concomitantemente cursan con enfermedades crónicas y estados de inmunosupresión. Son escasos los casos reportados como causa de endocarditis en pacientes inmunocompetentes a nivel global por especies de este género. Se expone el caso de una mujer inmunocompetente de 44 años, sin antecedentes de importancia, en quien solo el diagnóstico microbiológico permitió confirmar la presencia de Kocuria kristinae como agente causal de su endocarditis infecciosa; la literatura señala la dificultad existente al momento de diferenciar la endocarditis producida por Staphylococcus spp. versus Kocuria kristinae por su evolución clínica similar, indicando la importancia de la microbiología al momento de identificar y diagnosticar apropiadamente.

Members of the genus Kocuria correspond to ubiquitous, generally harmless, Gram-positive cocci that are part of the saprophytic flora of a significant percentage of the population; occasionally they have been described as the agents responsible for infectious pathologies, mainly in the context of patients who concomitantly have chronic diseases and are under an immunosuppression state. There are few cases reported as a cause of endocarditis in immunocompetent patients globally by species of this genus. We present the case of a 44-year-old immunocompetent woman, with no relevant history, in whom only the microbiological diagnosis confirmed the presence of Kocuria kristinae as the causative agent of her infectious endocarditis; Literature points out the difficulty existing when differentiating endocarditis produced by Staphylococcus spp. versus Kocuria kristinae because of their similar clinical evolution, indicating the importance of microbiology when identifying and diagnosing accurately.

Gut microbiota in Mexican patients with common variable immunodeficiency

Introduction: Common variable immunodeficiency (CVID) is the main symptomatic primary immunodeficiency and is associated with complex immune disorders. Gut microbiota interacts closely with the immune system, and intestinal dysbiosis is related to multiple diseases. Objective: To describe for the first time the composition of gut microbiota in Mexican patients with CVID. Methods: Fecal samples from five patients with CVID were collected and massive sequencing of the V3-V4 region of 16S rRNA gene was carried out using illumina technology. Results: Bacterial relative abundance was observed at all taxonomic levels. Firmicutes, Actinobacteria and Verrucomicrobia were the predominant phyla. The Clostridia class and the Clostridial order were the most common in their respective taxon; the Ruminococcaceae family predominated. A total of 166 genera were reported, with the most abundant being Faecalibacterium. Five species were identified, but only Bifidobacterium longum was present in all patients. Conclusions: Unlike healthy subjects' gut microbiota, where Firmicutes and Bacteroidetes predominate, the microbiota of the patients with CVID considered in this study was abundant in Firmicutes, Actinobacteria and Verrucomicrobia. The low presence of Bacteroidetes and high abundance of Firmicutes might indicate the existence of intestinal dysbiosis in these patients.

Diversidad bacteriana en el biocátodo reductor de Cr(VI) de una Celda de Combustible Microbiana con puente salino / Bacterial diversity in the Cr(VI) reducing biocathode of a Microbial Fuel Cell with salt bridge

Although Cr(VI)-reducing and/or tolerant microorganisms have been investigated, there is no detailed information on the composition of the microbial community of the biocathode microbial fuel cell for Cr(VI) reduction. In this investigation, the bacterial diversity of a biocathode was analyzed using 454 pyrosequencing of the 16S rRNA gene. It was found that most bacteria belonged to phylum Proteobacteria (78.8%), Firmicutes (7.9%), Actinobacteria (6.6%) and Bacteroidetes (5.5%), commonly present in environments contaminated with Cr(VI). The dominance of the genus Pseudomonas (34.87%), followed by the genera Stenotrophomonas (5.8%), Shinella (4%), Papillibacter (3.96%), Brevundimonas (3.91%), Pseu-dochrobactrum (3.54%), Ochrobactrum (3.49%), Hydrogenophaga (2.88%), Rhodococcus (2.88%), Fluviicola (2.35%), and Alcaligenes (2.3%), was found. It is emphasized that some genera have not previously been associated with Cr(VI) reduction. This biocathode from waters contaminated with tannery effluents was able to remove Cr(VI) (97.83%) in the cathodic chamber. Additionally, through use of anaerobic sludge in the anodic chamber, the removal of 76.6% of organic matter (glucose) from synthetic waste water was achieved. In this study, an efficient biocathode for the reduction of Cr(VI) with future use in bioremediation, was characterized.

Aunque se ha investigado sobre los microorganismos reductores y/o tolerantes de Cr(VI), no hay información detallada sobre la composición de la comunidad microbiana del cátodo de una Celda de Combustible Microbiana para la reducción de Cr(VI). En esta investigación se analizó la diversidad bacteriana de un biocátodo usando pirosecuenciación 454 del gen 16S rRNA. Se encontró que la mayoría de las bacterias pertenecieron a los filos Proteobac-teria (78,8%), Firmicutes (7,9%), Actinobacteria (6,6%) y Bacteroidetes (5,5%), comúnmente presentes en ambientes contaminados con Cr(VI). Se encontró como género dominante a Pseudomonas (34,87%), seguido por los géneros Stenotrophomonas (5,8%), Shinella (4%), Papil-libacter (3,96%), Brevundimonas (3,91%), Pseudochrobactrum (3,54%), Ochrobactrum (3,49%), Hydrogenophaga (2,88%), Rhodococcus (2,88%), Fluviicola (2,35%) y Alcaligenes (2,3%). Se destaca que algunos géneros no han sido previamente asociados con la reducción de Cr(VI). Este biocátodo procedente de aguas contaminadas con efluentes de curtiembres fue capaz de remover Cr(VI) (97,83%) en la cámara catódica. Adicionalmente, a través del uso de lodo anaeróbico en la cámara anódica, se logró la remoción del 76,6% de materia orgánica (glucosa) a partir de agua residual sintética. En este estudio se caracterizó un eficiente biocátodo para la reducción de Cr(VI) con futuro uso en biorremediación.

Antimicrobial activity of actinomycetes and characterization of actinomycin-producing strain KRG-1 isolated from Karoo, South Africa

In the present study we reported the antimicrobial activity of actinomycetes isolated from aridic soil sample collected in Karoo, South Africa. Eighty-six actinomycete strains were isolated and purified, out of them thirty-four morphologically different strains were tested for antimicrobial activity. Among 35 isolates, 10 (28.57%) showed both antibacterial and antifungal activity. The ethyl acetate extract of strain KRG-1 showed the strongest antimicrobial activity and therefore was selected for further investigation. The almost complete nucleotide sequence of the 16S rRNA gene as well as distinctive matrix-assisted laser desorption/ionization-time-of-flight/mass spectrometry (MALDI-TOF/MS) profile of whole-cell proteins acquired for strain KRG-1 led to the identification of Streptomyces antibioticus KRG-1 (GenBank accession number: KX827270). The ethyl acetate extract of KRG-1 was fractionated by HPLC method against the most suppressed bacterium Staphylococcus aureus (Newman). LC//MS analysis led to the identification of the active peak that exhibited UV-VIS maxima at 442 nm and the ESI-HRMS spectrum showing the prominent ion clusters for [M-H2O+H]+ at m/z 635.3109 and for [M+Na]+ at m/z 1269.6148. This information could be assigned to chromopeptide lactone antibiotic - actinomycin. Our results suggest that unexplored soils could be an interesting source for exploring antibacterial secondary metabolites.

Septic shock caused by the under-recognized bacterium Eggerthella lenta in a 61-year-old male with a periurethral abscess: a case report

Abstract Eggerthella lenta is a gram-positive anaerobic bacillus that has been associated with life-threatening infections. Bacteremia is always clinically significant and is mostly but not always associated with gastrointestinal disease. We present a unique case of abrupt deterioration and rapid development of septic shock secondary to periurethral abscess caused by E. lenta infection. This case highlights the atypical clinical presentation, risk factors, uncommon source of infection, challenges in therapy, and outcome of this infrequent infection. There is still a gap in the understanding of E. lenta pathogenicity, and more literature is needed to establish clear management recommendations.

Endophytic Actinomycetes as Potential Producers of Hemicellulases and Related Enzymes for Plant Biomass Degradation

Abstract Tailor made enzymatic preparation must be design to hydrolyze efficiently plant biomass, once that each plant biomass possesses a distinct cell wall composition. Most of actinomycetes used for plant cell wall degradation are focused on the cellulases and xylanases production. However, a wide range of enzymes must be produced for an efficient degradation of lignocellulose materials. During the last decade several unusual environments were studied to obtain strains that produce glycohydrolases with innovator characteristics. In this context, the present work concerned the selection of endophytic actinomycetes as producers of hemicellulases and related enzymes with different enzymatic profiles, for use in the deconstruction of lignocellulosic biomass. A total of 45 Brazilian actinomycetes previously isolated from plants (endophytics) and soil were prospected for hemicellulases and β-glucosidase production. Four strains highlighted for hemicellulase production (DR61, DR63, DR69 and DR66) and were selected for cultivation under other inductors substrates (xylan and pectin). All strains belong to Streptomyces genera and have their extracts tested for degradation of several hemicellulolytic substrates. The strains presented different glicohydrolyse enzymes profiles mainly for xylans and glucans that can be used for specific formulations of enzymes applied on the biomass deconstruction, principally on sugar cane bagasse.

Changes induced by co-inoculation in nitrogen-carbon metabolism in cowpea under salinity stress

ABSTRACT To mitigate the deleterious effects of abiotic stress, the use of plant growth-promoting bacteria along with diazotrophic bacteria has been increasing. The objectives of this study were to investigate the key enzymes related to nitrogen and carbon metabolism in the biological nitrogen fixation process and to elucidate the activities of these enzymes by the synergistic interaction between Bradyrhizobium and plant growth-promoting bacteria in the absence and presence of salt stress. Cowpea plants were cultivated under axenic conditions, inoculated with Bradyrhizobium and co-inoculated with Bradyrhizobium sp. and Actinomadura sp., Bradyrhizobium sp. and Bacillus sp., Bradyrhizobium sp. and Paenibacillus graminis, and Bradyrhizobium sp. and Streptomycessp.; the plants were also maintained in the absence (control) and presence of salt stress (50 mmolL-1 NaCl). Salinity reduced the amino acids, free ammonia, ureides, proteins and total nitrogen content in nodules and increased the levels of sucrose and soluble sugars. The co-inoculations responded differently to the activity of glutamine synthetase enzymes under salt stress, as well as glutamate synthase, glutamate dehydrogenase aminating, and acid invertase in the control and salt stress. Considering the development conditions of this experiment, co-inoculation with Bradyrhizobium sp. and Bacillus sp. in cowpea provided better symbiotic performance, mitigating the deleterious effects of salt stress.

Dose-response effect of crude extracts produced by actinobacteria on in vitro rumen fermentation / Padrão dose-resposta de extratos brutos produzidos por actinobactérias sobre a fermentação ruminal in vitro

Actinobacteria have been researched as a source that produces crude extracts, which contain bioactive compounds able to act as antimicrobial agents. The present investigation evaluated the dose-response effect of two crude extracts, obtained at Caatinga rhizosphere (Caat) and Rhizophora mangle (AMC), on in vitro ruminal fermentation by:cumulative gas production, digestibility of dry (IVDMD) and organic matter (IVOMD), and short-chain fatty acids concentration (SCFA). Three multiparous Holstein dairy cows with ruminal fistula were used as the inoculum donors and fed a basal diet consisting of corn silage, soybean meal, urea, ground corn and mineral supplement. Ruminal fluid samples were incubated in glass bottles with 1 g of the dried and milled diet, a buffer solution, and the crude extracts evaluated in four doses (0.3, 0.6, 0.9 and 1.20 mg/10 mL inoculum) in a randomized block design, and the donators were considered as blocks with random effects. Additionally, negative controls were used. The results were expressed as average values based on triplicate analyses. Decreased cumulative gas production was observed according to linear dose response at 24, 48 and 72 h of incubation with the addition of Caat extract. The IVOMD showed a linear decrease at 72 h of incubation with dose Caat inclusion. Furthermore, the inclusion of Caat extract linearly reduced butyric and isovaleric acid concentrations, as well as acetate:propionate ratio. Finally, the Caat inclusion increased the propionic acid concentration in comparison to AMC extract. However, the inclusion of AMC extract did not affect any of the analyzed variables at the used doses. The Caat extract could be used as a modulator of in vitro ruminal fermentation, since it reduced acetate:propionate ratio and cumulative gas production.(AU)

As actinobactérias têm sido pesquisadas como fonte produtoras de extratos brutos que contêm compostos bioativos capazes de atuar como agentes antimicrobianos. O presente trabalho investigou o efeito dose-resposta de dois extratos brutos, AMC e Caat, na fermentação ruminal in vitro por: produção cumulativa de gás, digestibilidade in vitro da matéria seca (IVDMD) e matéria orgânica (IVOMD) e concentração de ácidos graxos de cadeia curta (SCFA). Três vacas leiteiras da raça Holandesa, multíparas e portadoras de fístula ruminal foram utilizadas como doadoras de inóculo ruminal e foram alimentadas com uma dieta basal composta por silagem de milho, farelo de soja, ureia, milho moído e suplemento mineral. As amostras de inóculo ruminal foram incubadas em garrafas de vidro com 1 g da dieta seca e moída, solução tampão e os extratos brutos avaliados em quatro doses (0,3, 0,6, 0,9 e 1,20 mg/10 mL de inóculo) em delineamento em blocos casualizados, sendo as doadoras consideradas os blocos como efeito aleatório. Além disso, foram utilizados controles negativos para a correção da produção de gás. Os resultados foram expressos como valores médios com base em análises triplicadas. A diminuição da produção cumulativa de gás foi observada de acordo com a dose em resposta linear às 24, 48 e 72 h de incubação com a adição de extrato de Caat. A IVOMD mostrou uma diminuição linear com 72 h de incubação com inclusão de Caat. Além disso, a inclusão do Caat reduziu linearmente as concentrações de ácido butírico e isovalérico, bem como a proporção de acetato/propionato. Diferentemente, a inclusão do extrato de AMC não afetou nenhuma das variáveis analisadas nas doses utilizadas. O extrato de Caat pode ser usado como um modulador da fermentação ruminal in vitro, uma vez que reduziu a proporção de acetato/propionato e a produção de gás acumulada. (AU)

Anaerobic biodegradation of benzo(a)pyrene by a novel Cellulosimicrobium cellulans CWS2 isolated from polycyclic aromatic hydrocarbon-contaminated soil

Abstract Cellulosimicrobium cellulans CWS2, a novel strain capable of utilizing benzo(a)pyrene (BaP) as the sole carbon and energy source under nitrate-reducing conditions, was isolated from PAH-contaminated soil. Temperature and pH significantly affected BaP biodegradation, and the strain exhibited enhanced biodegradation ability at temperatures above 30 °C and between pH 7 and 10. The highest BaP removal rate (78.8%) was observed in 13 days when the initial BaP concentration was 10 mg/L, and the strain degraded BaP at constant rate even at a higher concentration (50 mg/L). Metal exposure experimental results illustrated that Cd(II) was the only metal ion that significantly inhibited biodegradation of BaP. The addition of 0.5 and 1.0 g/L glucose enhanced BaP biodegradation, while the addition of low-molecular-weight organic acids with stronger acidity reduced BaP removal rates during co-metabolic biodegradation. The addition of phenanthrene and pyrene, which were degraded to some extent by the strain, showed no distinct effect on BaP biodegradation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the five rings of BaP opened, producing compounds with one to four rings which were more bioavailable. Thus, the strain exhibited strong BaP degradation capability and has great potential in the remediation of BaP-/PAH-contaminated environments.

Effect of sulfonylurea tribenuron methyl herbicide on soil Actinobacteria growth and characterization of resistant strains

ABSTRACT Repeated application of pesticides disturbs microbial communities and cause dysfunctions on soil biological processes. Granstar® 75 DF is one of the most used sulfonylurea herbicides on cereal crops; it contains 75% of tribenuron-methyl. Assessing the changes on soil microbiota, particularly on the most abundant bacterial groups, will be a useful approach to determine the impact of Granstar® herbicide. For this purpose, we analyzed Actinobacteria, which are known for their diversity, abundance, and aptitude to resist to xenobiotic substances. Using a selective medium for Actinobacteria, 42 strains were isolated from both untreated and Granstar® treated soils. The number of isolates recovered from the treated agricultural soil was fewer than that isolated from the corresponding untreated soil, suggesting a negative effect of Granstar® herbicide on Actinobacteria community. Even so, the number of strains isolated from untreated and treated forest soil was quite similar. Among the isolates, resistant strains, tolerating high doses of Granstar® ranging from 0.3 to 0.6% (v/v), were obtained. The two most resistant strains (SRK12 and SRK17) were isolated from treated soils showing the importance of prior exposure to herbicides for bacterial adaptation. SRK12 and SRK17 strains showed different morphological features. The phylogenetic analysis, based on 16S rRNA gene sequencing, clustered the SRK12 strain with four Streptomyces type strains (S. vinaceusdrappus, S. mutabilis, S. ghanaensis and S. enissocaesilis), while SRK17 strain was closely related to Streptomyces africanus. Both strains were unable to grow on tribenuron methyl as unique source of carbon, despite its advanced dissipation. On the other hand, when glucose was added to tribenuron methyl, the bacterial development was evident with even an improvement of the tribenuron methyl degradation. In all cases, as tribenuron methyl disappeared, two compounds were detected with increased concentrations. These by-products appeared to be persistent and were not degraded either chemically or by the studied strains. Based on these observations, we suggested that bacterial activity on carbon substrates could be directly involved in the partial breakdown of tribenuron methyl, by generating the required acidity for the first step of the hydrolysis. Such a process would be interesting to consider in bioremediation of neutral and alkaline tribenuron methyl-polluted soils.

Next-generation sequencing analysis reveals high bacterial diversity in wild venomous and non-venomous snakes from India

The oral cavities of snakes are replete with various types of bacterial flora. Culture-dependent studies suggest that some of the bacterial species are responsible for secondary bacterial infection associated with snakebite. A complete profile of the ophidian oral bacterial community has been unreported until now. Therefore, in the present study, we determined the complete bacterial compositions in the oral cavity of some snakes from India. Methods: Total DNA was isolated from oral swabs collected from three wild snake species (Indian Cobra, King Cobra and Indian Python). Next, the DNA was subjected to PCR amplification of microbial 16S rRNA gene using V3-region-specific primers. The amplicons were used for preparation of DNA libraries that were sequenced on an Illumina MiSeq platform. Results: The cluster-based taxonomy analysis revealed that Proteobacteria and Actinobacteria were the most predominant phyla present in the oral cavities of snakes. This result indicates that snakes show more similarities to birds than mammals as to their oral bacterial communities. Furthermore, our study reports all the unique and common bacterial species (total: 147) found among the oral microbes of snakes studied, while the majority of commonly abundant species were pathogens or opportunistic pathogens to humans. A wide difference in ophidian oral bacterial flora suggests variation by individual, species and geographical region. Conclusion: The present study would provide a foundation for further research on snakes to recognize the potential drugs/antibiotics for the different infectious diseases.(AU)

Characterization of dioxygenases and biosurfactants produced by crude oil degrading soil bacteria

ABSTRACT Role of microbes in bioremediation of oil spills has become inevitable owing to their eco friendly nature. This study focused on the isolation and characterization of bacterial strains with superior oil degrading potential from crude-oil contaminated soil. Three such bacterial strains were selected and subsequently identified by 16S rRNA gene sequence analysis as Corynebacterium aurimucosum, Acinetobacter baumannii and Microbacterium hydrocarbonoxydans respectively. The specific activity of catechol 1,2 dioxygenase (C12O) and catechol 2,3 dioxygenase (C23O) was determined in these three strains wherein the activity of C12O was more than that of C23O. Among the three strains, Microbacterium hydrocarbonoxydans exhibited superior crude oil degrading ability as evidenced by its superior growth rate in crude oil enriched medium and enhanced activity of dioxygenases. Also degradation of total petroleum hydrocarbon (TPH) in crude oil was higher with Microbacterium hydrocarbonoxydans. The three strains also produced biosurfactants of glycolipid nature as indicated d by biochemical, FTIR and GCMS analysis. These findings emphasize that such bacterial strains with superior oil degrading capacity may find their potential application in bioremediation of oil spills and conservation of marine and soil ecosystem.

Susceptibilidad antimicrobiana en aislamientos de secreción endotraqueal en la unidad de cuidados intensivos de un hospital nacional de Lima, 2016 / Antimicrobial susceptibility among endotracheal isolates in an intensive care unit in Lima, 2016

Objetivos: Determinar la frecuencia de microorganismos y el patrón de susceptibilidad antimicrobiana en aislamientos de cultivos de secreción endotraqueal en la unidad de cuidados intensivos de un hospital nacional de Lima. Material y métodos: Estudio observacional, descriptivo. Se incluyeron 195 cultivos positivos de secreción endotraqueal de pacientes en ventilación mecánica durante el periodo enero a diciembre del 2016. Resultados: Acinetobacter sp. fue la bacteria más frecuentemente aislada (28%) seguido por Pseudomonas aeruginosa (22%) y Klebsiella pneumoniae (14%), Los aislamientos con Acinetobacter sp. presentaron una elevada resistencia a antibióticos carbapenémicos (meropenem 90% eimipenem 88%). Conclusiones: Se identificó una elevada frecuencia de Acinetobacter sp. En cultivos de secreción traqueal en la unidad de cuidados intensivos, con un patrón de multirresistencia. (AU)

Objectives: To determine the prevalence of micro-organisms and their susceptibility pattern among endotracheal isolates in an intensive care unit in national hospital in Lima. Methods: An observational, descriptive study was carried-out from January to December 2016, 195 positive isolates from endotracheal aspirates of patients under mechanical ventilation were analyzed. Results: Acinetobacter spp. was the most common bacteria isolates (28%), followed by Pseudomonas aeruginosa (22%) and Klebsiella pneumoniae (14%). Acinetobacter spp. was highly resistant to carbapenems (90% to meropenem and 88% to imipenem). Conclusions: Multi-drug resistant Acinetobacter spp. was the most common pathogen isolated in this setting. (AU)

Antimicrobial Activity and Biocompatibility of the Psidium cattleianum Extracts for Endodontic Purposes

Abstract Psidium cattleianum (PC) has been displaying inhibitory effect against a variety of microorganisms, but this effect has not yet been tested against endodontic pathogens. The aim of this study was to evaluate the antimicrobial activity and biocompatibility of the aqueous (PCAE) and hydroethanolic (PCHE) extracts from Psidium cattleianum (PC) leaves. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the microdilution broth method in order to analyze the antimicrobial effect against Enterococcus faecalis, Pseudomonas aeruginosa, Actinomyces israelii and Candida albicans in planktonic conditions. Biofilm assays were conducted only with the extracts that were able to determine the MLC for microorganisms in planktonic conditions. Immediate and late tissue reactions against PC extracts were evaluated using edemogenic test and histological analysis of subcutaneous implants in Wistar rats. The results showed that the MIC and MLC values ranged between 0.25 and 4 mg/mL. The MLC obtained for PCHE inhibited 100% growth of all the tested strains, except for C. albicans. PCAE had the same effect for E. faecalis and P. aeruginosa. Both PC extracts were able to eliminate E. faecalis biofilms and only the PCHE eliminated P. aeruginosa biofilms. The positive controls inhibited the growth of all tested strains in MIC and MLC essays, but no CHX tested concentrations were able to eliminate A. israelii biofilm. PCAE caused a discrete increase in the edema over time, while PCHE caused a higher initial edema, which decreased progressively. Both PCAE and PCHE extracts were biocompatible, but PCHE showed better results with slight levels of inflammation at 28 days. In conclusion, PCHE was biocompatible and presented better antimicrobial effect against important pathogens associated with persistent endodontic infections

Resumo Psidium cattleianum (PC) tem apresentado atividade inibitória frente diversos microrganismos, entretanto esse efeito ainda não foi testado contra microrganismos de interesse endodôntico. O objetivo desse estudo foi avaliar a atividade antimicrobiana e a biocompatibilidade dos extratos aquoso (EAPC) e hidroetanólico (EHPC) das folhas de Psidium cattleianum. As concentrações inibitória mínima (CIM) e letal mínima (CLM) foram determinadas pelo método de microdiluição em caldo, com o objetivo de analisar o efeito antimicrobiano frente Enterococcus faecalis, Pseudomonas aeruginosa, Actinomyces israelii e Candida albicans em condições planctônicas. Os ensaios de biofilme foram realizados somente com os extratos em que se determinou a CLM frente os microrganismos em condições planctônicas. Respostas teciduais imediata e tardia frente aos extratos de Psidium cattleianum foram avaliadas por teste edemogênico e análise histológica de implantes subcutâneos em ratos Wistar. Os resultados mostraram que CIM e CLM variaram entre 0,25 e 4 mg/mL. As CLMs determinadas pelo EHPC inibiram 100% do crescimento de todas as cepas testadas, exceto Candida albicans. EAPC apresentou o mesmo efeito para E. faecalis e P. aeruginosa. Ambos os extratos de PC conseguiram eliminar o biofilme de E. faecalis, e somente o EHPC eliminou o biofilme de P. aeruginosa. Os controles positivos inibiram o crescimento de todos os microrganismos testados nos ensaios de CIM e CLM, mas nenhuma das concentrações de clorexidina testadas foi capaz de eliminar o biofilme de A. israelii. O EAPC provocou um discreto aumento de edema com o tempo, enquanto EHPC provocou um edema inicial severo, que diminuiu progressivamente. Ambos os extratos EAPC e EHPC foram biocompatíveis, entretanto, EHPC apresentou melhores resultados com baixos níveis de inflamação em 28 dias. Pode-se concluir que EHPC foi biocompatível e apresentou melhor efeito antimicrobiano frente importantes patógenos associados a infecções endodônticas persistentes.

Potential for biocontrol of melanized fungi by actinobacteria isolated from intertidal region of Ilha Do Mel, Paraná, Brazil

Abstract Actinobacteria occur in many environments and have the capacity to produce secondary metabolites with antibiotic potential. Identification and taxonomy of actinobacteria that produce antimicrobial substances is essential for the screening of new compounds, and sequencing of the 16S region of ribosomal DNA (rDNA), which is conserved and present in all bacteria, is an important method of identification. Melanized fungi are free-living organisms, which can also be pathogens of clinical importance. This work aimed to evaluate growth inhibition of melanized fungi by actinobacteria and to identify the latter to the species level. In this study, antimicrobial activity of 13 actinobacterial isolates from the genus Streptomyces was evaluated against seven melanized fungi of the genera Exophiala, Cladosporium, and Rhinocladiella. In all tests, all actinobacterial isolates showed inhibitory activity against all isolates of melanized fungi, and only one actinobacterial isolate had less efficient inhibitory activity. The 16S rDNA region of five previously unidentified actinobacterial isolates from Ilha do Mel, Paraná, Brazil, was sequenced; four of the isolates were identified as Streptomyces globisporus subsp. globisporus, and one isolate was identified as Streptomyces aureus. This work highlights the potential of actinobacteria with antifungal activity and their role in the pursuit of novel antimicrobial substances.