Ana Frazzon

Enterococcus faecalis strains have a ubiquitous nature that allows them to survive in different niches. Studies involving enterococci isolated from marine animals are scarce. Therefore, in this study, we report the complete genome sequence of E. faecalis strain P8-1 isolated from feces of a Magellanic penguin on the south coast of Brazil.

Listeria monocytogenes is the foodborne pathogen responsible for a bacterial infection called listeriosis. Here, we present the whole-genome sequences of two L. monocytogenes serovars, 1/2a and 4b, which are considered the most prevalent in food processing plants and listeriosis outbreaks, respectively.

Exposure to subinhibitory concentrations (SICs) of antimicrobials may alter the bacterial transcriptome. Here, we evaluated the expression of nine virulence-related genes in vancomycin-resistant enterococci (VRE) urinary tract infection isolates grown at SICs of vancomycin. A Subinhibitory concentrations of vancomycin interferes with gene modulation, but does not affect the phenotype of a VRE strain in vitro . Subinhibitory concentrations of vancomycin may regulate the expression of virulence factors in vivo or contribute to the selection of vancomycin-resistant strains.

(Influência da fonte nutricional no crescimento ótimo e na produção de antimicrobianos produzidos por isolados de Streptomyces sp. ). Os actinomicetos são bactérias caracterizadas por sua habilidade em formar hifas, amplamente distribuídos no ambiente e conhecidos pela diversidade na produção de moléculas biologicamente ativas. O presente trabalho teve por objetivo avaliar a atividade de compostos produzidos por seis isolados de Streptomyces contra dezenove cepas de Enterococcus. O perfil de susceptibilidade dos Enterococcus foi avaliado para onze antibióticos, empregando a técnica de difusão de disco em ágar. A atividade antimicrobiana dos estreptomicetos foi avaliada pela técnica da dupla camada. Os isolados que apresentaram atividade foram cultivados em caldo amido caseína à temperatura de 30 ºC por sete dias, em agitação constante. Após crescimento, a cultura foi filtrada para obtenção do extrato bruto. A atividade antimicrobiana do extrato foi avaliada através da técnica de dif...

(Antimicrobial susceptibility profile of Enterococcussp. isolatedfrom Dilúvio stream waters, Porto Alegre, RS, Brazil). The aim of this study was to determine the frequency enterococci species from Dilúvio stream, in Porto Alegre RS, and the antimicrobial susceptibility profiles of the isolates to antibiotics of human and veterinary importance. From March to December 2009, water samples were collected from the stream into five distinct points. Three hundred and forty eight enterococci were isolated from water samples collected at five points along the course of the creek flood and identified to the species level through their phenotypic profiles and PCR. The most frequent specie was E. faecium (68.67%), followed by E. faecalis (16.09%), E. casseliflavus (12.07%), E. hirae (2.58%) and E.gallinarum (0.57%). Points 1 and 3 showed no significant differences between the species. The antimicrobial susceptibility tests revealed that isolateswereresistant to erythromycin (81.07%), nitrofura...

RESUMO Enterococcus faecalis são importantes patógenos hospitalares com uma notável capacidade de expressar resistência a vários agentes antimicrobianos. Sua natureza ubíqua e resistência às condições ambientais adversas o torna de fácil propagação através da cadeia alimentar. Devido a isso, o presente estudo investigou a variabilidade genética de 38 isolados de E. faecalis oriundos de carne de frango e de infecção urinária, pela técnica de RAPD-PCR. Para tanto foi utilizado o oligonucleotídeo iniciador M13 para verificar a existência de uma correlação genotípica entre os isolados. O dendrograma formado a partir do perfil RAPD-PCR dos isolados gerou 3 grupos (A, B e C). O grupo A foi composto de aproximadamente 74% (28/38) dos isolados clínicos e alimentares com perfil de multi-resistência a antimicrobianos e com 88% de similaridade. O grupo A foi subdivido em I e II, onde no sub-grupo I estão agrupados todos os isolados clínicos e o sub-grupo II foi composto pela maioria dos isolad...

Actinomycetes are Gram-positive bacteria widely distributed in the environment and known for the diverse biologically act ive molecules they produce. This study assesses the activity of compounds produced by 40 actinomycete isolates against Enterococcus spp. Staphylococcus aureus and Staphylococcus epidermidis clinical isoalates. The susceptibility profile of the samples was assessed using the agar disk diffusion method. Antimicrobial activity of actinomycetes was evaluated according to the double layer method. Here, two isolates (50 and 8S) exhibited activity against 90% of clinical Staphylococcus spp. and Enterococcus spp. These isolates were grown in starch casein broth at 30˚C for 7 days with constant shaking. After, the culture obtained was filtered to obtain a crude extract, whose antibiotic activity was assessed using the well diffusion technique. In this assay, isolate 50 presented higher activities than that exhibited by isolate 8S. The isolate 50 has been used in different...

Background: Salmonella is one of the principal causes of food-borne diseases transmitted all over the world and in the state of Rio Grande do Sul, Southern Brazil, this microorganism has been identified as the principal agent of food-borne outbreaks in the last years. The objective of this study was to characterize Salmonella enteritidis strains involved in food-borne outbreaks usingantimicrobial resistance and rapid genotyping methods.Methodology: Strains of Salmonella isolated from foods involved in salmonellosis occurring in the state of Rio Grande do Sul, in the period from 2001 to 2002 were characterized by antimicrobial resistance, PCR-ribotyping and RAPD.Results: Among the 79 S. enteritidis analysed by antibiotic resistance, 62.1% were susceptible to all drugs tested. The predominant resistance observed was to nalidixic acid (21.5%), gentamicin (12.7%), and streptomycin (11.4%). Resistance was demonstrated in 30 strains (30.9%), which were grouped in 14 different patterns. Th...

ABSTRACT Spot blotch disease, caused by Bipolaris sorokiniana, is one of the major diseases of wheat and is responsible for large losses of wheat crops worldwide. We used polymerase chain reaction (PCR) with universal rice primers (URP) for molecular characterization of 60 monosporic B. sorokiniana isolates from Brazil and other countries, and evaluated the diversity of the samples. PCR amplification generated 232 different DNA fragments ranging in size from 100 to 2018 bp. The primers URP-4R, URP-2R, and URP-1F generated greater numbers of amplified fragments (36, 30, and 25, respectively) from the single-spore isolates, and some diversity was observed among the isolates generated using these primers. The primers URP-2F, URP-6R, URP-17R, URP-30F, and URP-38F produced a pattern of monomorphic fragments and 73% of the isolates showed an average of 44 different DNA-amplified fragments. Primer URP-2F generated a 578-bp fragment that was common to 83.7% of the isolates; primer URP-6R generated a 548-bp fragment and primer URP-38F generated a 650- bp product that was common to 89.1% and 80% of the isolates, respectively. The URP-PCR primers provided important information about the genetic profiles of the monosporic cultures, which showed intraspecific variability among the monoconidial isolates and among the monosporic cultures that originated from the same polysporic strain. Our results indicate that URP’s are sensitive and give reproducible results for assaying the genetic variability of B. sorokiniana.

This study investigated the effectiveness of successive bioaugmentation, conventional bioaugmentation, and biostimulation of biodegradation of B10 in soil. In addition, the structure of the soil microbial community was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis. The consortium was inoculated on the initial and the 11th day of incubation for successive bioaugmentation and only on the initial day for bioaugmentation and conventional bioaugmentation. The experiment was conducted for 32 days. The microbial consortium was identified based on sequencing of 16S rRNA gene and consisted as Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Ochrobactrum intermedium. Nutrient introduction (biostimulation) promoted a positive effect on microbial populations. The results indicate that the edaphic community structure and dynamics were different according to the treatments employed. CO2 evolution demonstrated no significant difference in soil microbial activity between biostimulation and bioaugmentation treatments. The total petroleum hydrocarbon (TPH) analysis indicated a biodegradation level of 35.7 and 32.2 % for the biostimulation and successive bioaugmentation treatments, respectively. Successive bioaugmentation displayed positive effects on biodegradation, with a substantial reduction in TPH levels.

Attention-deficit/hyperactivity disorder is related to altered functions in the dopaminergic and GABAergic pathways of cortical and subcortical brain areas The hyperactivity of attention-deficit/hyperactivity disorder is commonly modelled in rats after neonatal lesion with 6-hydroxydopamine (6-OHDA), and amphetamines are effective in reducing hyperactivity in this animal model. Our objectives were to evaluate whether cocaine reverses the motor hyperactivity of 6-OHDA-lesioned rats and to verify cocaine effects in altered mRNA expression of alpha2, alpha4, beta1 and beta2-GABAA subunits and GAD isoenzymes in the prefrontal cortex, hippocampus and striatum of 6-OHDA-lesioned rats. On PND4, 6-OHDA-lesioned or sham rats received 6-OHDA (100 microg intracisternal) or vehicle. Cocaine solution (0.1 mg/ml/day) was offered when adult for 23 days, using the two-bottle choice procedure. The subjects were evaluated in an open-field on the last day of cocaine treatment. 6-OHDA-lesioned rats showed increased locomotion and this hyperactivity was reversed during cocaine self-administration. 6-OHDA lesion caused an increase in the mRNA expression of GABAA subunits in specific brain areas and GAD isoenzymes in the hippocampus and striatum. Increased GAD65 and decreased GAD67 mRNA expression were also shown in the prefrontal cortex. Cocaine self-administration attenuated the effects of 6-OHDA lesions on the mRNA expression of alpha2-GABAA and beta2-GABAA subunits in the prefrontal cortex, reversed the mRNA expression of alpha2-GABAA subunits in the striatum and of alpha4-GABAA subunits in the prefrontal cortex and in the hippocampus, and reversed the mRNA expression of GAD65 and GAD67 in the brain areas studied. Our findings suggest that cocaine reverses some mRNA changes of GABAA subunits and GAD isoenzymes in reward circuits and the behavioural hyperactivity caused by 6-OHDA lesion.