Agueda Castagna de Vargas

Atividade antibacteriana de extrato hidro-alcoólico de folhas de jambolão (Syzygium cumini (L.) Skells)

The antimicrobial activity of medicinal plants has been searched in diverse species, as much in Brazil as in other countries. The aim of this study was to evaluate the existence of hydro-alcoholic extract jambolan leaves 10% (w/v) antibacterial effect. Seventeen Gram positive and Gram negative isolated bacterial were used. The antibacterial action was evaluated through the inoculation of Mueller Hinton agar plates, with a bacterial inoculate of 3x10 8 cell/ mL, with four paper discs, being the first of commercial antimicrobial and the others embedded with 25µL of the extract, saline or ethanol. The plates were incubated at 37°C for 24 hours, and their reading of inhibition hales diameter was done. The extract inhibited the growth of 100% of the tested bacteria; the Gram positive isolates had presented an average hale of 19.5mm, while of the Gram negative was of 18.8mm. There was not significant inhibition of growth in treatments with saline and ethanol. As verified in this study, the tested extract presents antibacterial activity against all the isolates, without sensitivity difference among Gram positive and Gram negative microorganisms.

Atividade antimicrobiana “in vitro” de extrato alcóolico de própolis

O genero Candida sp . compreende 200 especies conhecidas, mas somente uma dezena de especies possui a faculdade de adaptar-se a temperatura de 37°C, podendo ser, ocasionalmente, patogenicas para o homem. Entre elas, estao: C. albicans, C. tropicalis, C. kefyr (pseudotropicalis),C. krusei, C. guilliermondii, C. parakrusei, C. zeylainoides, C.stellatoidea e C. brumpti i. A candidiase e a principal infeccao fungica oportunista do ser humano, causada por leveduras do genero Candida sp ., que fazem parte da microbiota endogena do corpo humano. Por isso, podem acometer hospedeiros sadios, mas a maioria das candidiases se desenvolve em individuos imuno comprometidos, como os pacientes infectados pelo HIV, os que receberam transplante de um orgao, os que fazem tratamento com citostaticos, corticoides e tratamento prolongado com antibacterianos de amplo espectro. Alem disso,o comprometimento de barreiras anatomicas secundariamente a queimadura ou procedimentos invasivos, comoo cateterismo, abrem portas para a invasao.

Phenotypic and molecular characterization of bovine Campylobacter fetus strains isolated in Brazil

The objective of the present study was to characterize the phenotypic and molecular aspects of Campylobacter fetus strains isolated from bovine herds with reproductive problems. Thirty-one Brazilian field isolates, together with one reference strain of each subspecies of C. fetus, were analyzed. The strains were submitted to phenotypic identification followed by subspecies characterization using the polymerase chain reaction (PCR) and numeric evaluation of restriction fragment length polymorphism (RFLP) separated by pulsed-field gel electrophoresis (PFGE). Phenotypically, 4 isolates (12.1%) were classified as C. fetus subsp. fetus, and 29 isolates (87.9%) were classified as C. fetus subsp. venerealis. However, according to molecular analysis, only 1 isolate (3.0%) was classified as C. fetus subsp. fetus (the reference strain), whereas 32 isolates (97.0%) were considered C. fetus subsp. venerealis. SalI digestion of C. fetus genomic DNA, obtained from the 33 strains, yielded 7-10 DNA fragments ranging in size from 40 to 373kb, with 12 distinct patterns. Furthermore, the numeric analysis by neighbor-joining of the DNA from the 33 strains resulted in a dendrogram in which 2 distinct groups were identified. It was concluded that phenotypic characterization of C. fetus subspecies might lead to erroneous classification of field isolates. Although RFLP-PFGE is a powerful and reliable technique to characterize C. fetus, it has the inconvenience of being time consuming and laborious. Whereas PCR, besides providing rapid results, was found to be reliable and convenient for the characterization of field isolates of C. fetus.

Caracterização epidemiológica, molecular e perfil de resistência aos antimicrobianos de Escherichia coli isoladas de criatórios suínos do sul do Brasil

Colibacillosis is an enteric disease with a major impact to the swine industry and is caused by enterotoxigenic strains of Escherichia coli. Forty clinical isolates from pigs with diarrhea and 13 environmental isolates were analysed regarding their genotypic profile, genetic relationship and antibiotic resistance. The most prevalent gene was Stb, identified in 50% of the isolates from clinical cases, and Sta and Lt were detected in 35% of them. Among the adesine factors investigated, F18 was found in 27.5% of the E. coli strains. The ERIC-PCR technique used for epidemiological characterization of the isolates did not show the expected discriminatory power. However, the test allowed separation of the isolates in groups, but did not evidence groups related to virulence factors. In the susceptibility test, the highest values for resistance were to tetracycline, in 88.6%. The index of multiple resistance to antimicrobials varied from 0 to 0.69.

Antimicrobial activity of propolis extract against Staphylococcus coagulase positive and Malassezia pachydermatis of canine otitis.

The aims of this study were to evaluate the antimicrobial potential of propolis extract by determining the minimum bactericidal concentration (MBC) for coagulase-positive Staphylococcus isolates (Staphylococcus aureus and Staphylococcus intermedius) and the minimum fungicidal concentration (MFC) for Malassezia pachydermatis isolates. The microorganisms were assayed using broth microdilution techniques. The MBC(90) was 21 mg mL(-1), and the MFC(90) was 5.3 mg mL(-1). The propolis extract was found to exhibit antimicrobial activity against both pathogens.

Isolation of Prothoteca zopfii from a case of bovine mastitis in Brazil

The isolation of Prothoteca zopfii, an algae lacking chlorophyll, from bovine mastitic milk, is described herein. The isolation was performed on 8% sheep blood agar, following incubation at 37 °C for 48 h. Based on biochemical tests, susceptibility to clotrimazole, and light and electron microscopic observation of cellular morphology the algae was identified as P. zopfii . The affected animal did not improve following treatment and had to be eliminated.

The use of eugenol against Aeromonas hydrophila and its effect on hematological and immunological parameters in silver catfish (Rhamdia quelen)

The aim of this study was to evaluate the activity of eugenol against the fish pathogen Aeromonas hydrophila and eugenols effect on hematological and natural immune parameters in silver catfish (Rhamdia quelen). In vitro, eugenol showed weak activity against A. hydrophila, but in vivo, at a subinhibitory concentration (10 mg L(-1)), it promoted survival in infected silver catfish. Eugenol (50 μg mL(-1)) reduced the hemolytic activity of A. hydrophila supernatant in vitro in fish erythrocytes. Subjecting catfish to eugenol baths (5 and 10 mg L(-1)) for five days did not alter the hematological and immunological parameters studied in this work. Based on these results, eugenol can be used to treat or prevent bacterial diseases in fish.

Molecular characterization of Rhodococcus equi from horse-breeding farms by means of multiplex PCR for the vap gene family.

This study evaluated the molecular characteristics of Rhodococcus equi isolates obtained from horses by a multiplex PCR assay that amplifies the vap gene family (vapA, -B, -C, -D, -E, -F, -G, and -H). A total of 180 R. equi isolates were studied from four different sources, namely healthy horse feces (112), soil (12), stalls (23), and clinical isolates (33) from horse-breeding farms. The technique was performed and confirmed by sequencing of amplified vap gene family controls. Thirty-two (17.8%) of the R. equi isolates were positive for the vapA gene and carried at least three other vap genes. All 147 isolates from equine feces, stalls, and soil failed to demonstrate any genes associated with virulence-inducing proteins. About 32 (97.0%) out of the 33 clinical equine isolates tested positive for the multiplex PCR assay for the vap gene family. They demonstrated six molecular profiles: 100% featured the vapA, vapD, and vapG genes, 86.6% vapF, 76.6% vapH, 43.3% vapC, 36.6% vapE, and none vapB. The most frequent molecular profile was vap A, -D, -F, G, and -H, where this profile was present in 37.5% of the strains. Moreover, there was no molecular epidemiological pattern for R. equi isolates that uniquely mapped to each horse-breeding farm studied. Our proposed technique allows the identification of eight members of the vap gene family (vapA, B, -C, -D, -E, -F, -G, and -H). It is a practical and efficient method of conducting clinical and epidemiological studies on R. equi isolates.

Virulence factors, antimicrobial resistance, and plasmid content of Escherichia coli isolated in swine commercial farms

Virulence factors and antimicrobial resistance patterns of Escherichia coli isolates were evaluated. A total of 80 E. coli isolates were evaluated, being 64 from clinical samples (intestinal content and fragments of organs from diarrheic piglets), seven from feces of clinically healthy piglets and sows, and nine environmental samples (five from facilities, two from feed, one from insect, and one from waste). Molecular characterization was performed by PCR detection of fimbriae and toxin genes and plasmid content determination. The isolates were also characterized according to their resistance or sensitivity to the following drugs: ampicillin, trimethoprim:sulfamethoxazole, tetracycline, amikacine, colistin, norfloxacin, florfenicol, enrofloxacin, cefalexin, trimethoprim, neomycin, chloramphenicol, and gentamicin. From 80 E. coli isolates, 53.8% were classified as enterotoxigenic E. coli (ETEC), 2.5% were shiga toxin-producing E. coli (STEC), and 43.8% showed a non specific pattern and were unclassified. One fecal isolate from non-diarrheic piglet was classified as ETEC by PCR. Clinical isolates showed resistance mainly for tetracycline and trimethoprim:sulfamethoxazole. Plasmidial DNA was observed in 70 isolates, being 78.5% of clinical isolates, 8.57% of non-diarrheic feces, and 12.8% of environment.

BACTÉRIAS COM POTENCIAL PATOGÊNICO NOS RINS E LESÕES EXTERNAS DE JUNDIÁS (Rhamdia quelen) CULTIVADOS EM SISTEMA SEMI-INTENSIVO

The main purpose of this study was to identify the pathogenic bacterial wich could be found in jundia (native fish) raised in ponds. This work also verified the relationship between the length of fishes, weigth, sex and water temperature related the number of bacterias isolated. One hundred fish were caught between December of 1995 and October of 1996. The bacterial examination was made from the kidney and also from the external lesion when present. From the one hundred necropsied fish, 35 showed bacterial growth. Eleven different bacterial were identified: Plesiomonas shigelloides(15%), Aeromonas sp. (6%), Flavobacterium sp. (5%), Acinetobacter sp. (4%), Vibrio sp. (4%), Pseudomonas sp. (4%), Micrococcus sp. (3%), Staphylococcus sp. (3%), Edwardsiella tarda (3%), Yersinia ruckeri (2%) e Pasteurella sp. (1%). No correlation was found between fish lenght, weight, sex and water temperature related to the number of isolated bacterias. For the first time Yersinia ruckeri was found in a brazilian fish.