Antibacterial activity of vegetal extracts against serovars of Salmonella / Atividade antibacteriana de extratos vegetais sobre sorovares de Salmonella

in vitro antibacterial activity of 21 hydroethanolic vegetal extracts was assessed against 20 serovars of Salmonella. Regarding the tested extracts, 85.7 percent of them presented antibacterial activity. The six active extracts which showed activity on the largest number of serovars and the extract of Eucalyptus sp. were submitted to the determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Of these, six extracts showed bacteriostatic and bactericidal activity with MIC and MBC for Punica granatum (pomegranate) from 20 and 60mg mL-1, for Eugenia jambolana (rose apple) from 40 and 240mg mL-1, Eugenia uniflora (surinam cherry) from 80 and 240mg mL-1, Caryophyllus aromaticus (clove) from 10 and 60mg mL-1, Psidium araca from 30 and 320mg mL-1 and Eucalyptus sp. from 40 and 160mg mL-1. Achyrocline satureioides (macela) presented only bacteriostatic potential and MIC from 160mg mL-1. Caryophyllus aromaticus, Eucalyptus sp., and Psidium araca presented the best results for bactericidal activity, inhibiting, respectively, 84.2 percent, 42.1 percent, and 17.6 percent of Salmonella's serovars. The activity of each extract varied for different serovars; S. London presented resistance to the six extracts in MBC, while S. Pullorum was the most susceptible serovar.

A atividade antibacteriana de 21 extratos hidroetanólicos vegetais foi avaliada in vitro frente a 20 sorovares de Salmonella. Dos extratos testados, 85,7 por cento apresentaram atividade antibacteriana. Os seis extratos que evidenciaram atividade sobre o maior número de sorovares e Eucalyptus sp. foram submetidos à determinação da Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM). Destes, seis extratos apresentaram atividade bacteriostática e bactericida com MIC para Punica granatum (romã) a partir de 20 e 60mg mL-1, Eugenia jambolana (jambolão) de 40 e 240mg mL-1, Eugenia uniflora (pitanga) de 80 e 240mg mL-1, Caryophyllus aromaticus (cravo) de 10 e 60mg mL-1, Psidium araca (araçá) 30 e 320mg mL-1 e Eucalyptus sp. (eucalipto) de 40 e 160mg mL-1. Achyrocline satureioides (macela) apresentou apenas atividade bacteriostática e MIC a partir de 160mg mL-1. Caryophyllus aromaticus, Eucalyptus sp. e Psidium araca apresentaram os melhores resultados para a atividade bactericida, inativando, respectivamente, 84,21 por cento, 42,1 por cento e 17,64 por cento dos sorovares de Salmonella. A atividade de cada extrato variou para diferentes sorovares. Nenhum dos seis extratos avaliados evidenciou atividade bactericida frente a S. London, enquanto S. Pullorum foi o sorovar mais sensível.

Oral treatment with bacteriophages reduces the concentration of Salmonella Enteritidis PT4 in caecal contents of broilers.

Bacteriophages isolated from free-range chickens were tested as a therapeutic agent for reducing the concentration of Salmonella enterica serovar Enteritidis phage type 4 (S. Enteritidis PT4) in caeca of broilers. One-day-old broilers infected with S. Enteritidis PT4 by a seeder bird method were orally treated on the seventh day of age with a mixture of 10(11) plaque-forming units of each of three bacteriophages. Five days after treatment the bacteriophage-treated group showed a reduction of 3.5 orders of magnitude on colony-forming units of S. Enteritidis PT4 per gram of caecal content. Samples collected at 10, 15, 20 and 25 days after treatment revealed that treated birds still had lower colony-forming units of S. Enteritidis PT4 per gram of caecal content. These data gave us compelling evidence that a mixture of bacteriophages may be efficacious in reducing S. Enteritidis PT4 concentration in broilers' caeca and therefore reducing contamination of poultry products by this food-borne pathogen.

Swine and poultry pathogens: the complete genome sequences of two strains of Mycoplasma hyopneumoniae and a strain of Mycoplasma synoviae.

This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.

Apparent eradication of Mycoplasma synoviae in broiler breeders subjected to intensive antibiotic treatment directed to control Escherichia coli.

A Mycoplasma synoviae (MS)-free flock of broiler breeders was housed for brooding and rearing on an MS endemic farm. PCR revealed that the flock became infected within nine weeks. At 22 weeks the flock was transferred to a clean and disinfected house on a previously depopulated farm. The birds were then subjected to three treatments with fluoroquinolones due to recurrent Escherichia coli peritonitis and from the 32 weeks of age they received 600 ppm of oxytetracycline hydrochloride continuously in the feed. Monitoring by PCR showed a decrease in MS positive birds after 34 weeks of age and MS may have been eradicated as judged by consistent negative results in PCR. We conclude that intensive antibiotic treatments supported by adequate biosecurity could clear MS from infected broiler breeders.

Inibiçäo do crescimento de fungos do grupo Aspergillus flavus pelo extrato da semente de "grapefruit" / Growth inhibition moulds of the group Aspergillus flavus by grapefruit seed extract

Nove isolados e uma amostra padräo de fungos do grupo Aspergillus flavus foram avaliados pela sensibilidade ao extrato da semente de "grapefruit". Os fungos foram submetidos a crescimento em ágar contendo 33,3//de extrato de coco-da-bahia e níveis do antifúngico que variavam logaritmamente desde 80 até 5120 ppm. Todas as amostras foram sensíveis ao antifúngico em comportamento linear nas doses testadas, porém, o extrato comportou-se como fungiostático, sendo as doses calculadas para inibiçäo de 99//do crescimento muito elevadas. No entanto, algumas concentraçöes foram satisfatórias, como 5000 ppm (0,5//), que causaram reduçäo de 80//do crescimento na maioria dos isolados

Comparaçäo entre liofilizaçäo e congelaçäo como métodos de conservaçäo de antígenos hemaglutinantes / Comparison between lyophilization and freezing for preserving avian mycoplasma hemagglutinating antigens

Avaliou-se o processo de liofilizaçäo como método alternativo para a prevençäo do título hemaglutinante dos antígenos de Mycoplasma synoviae e Mycoplasma gallisepticum. As amostras foram cultivadas em caldo frey para a obtençäo de duas partidas de antígenos e a outra à congelaçäo a -80 §C, para a conservaçäo durante 120 dias. Os antígenos hemaglutinantes foram titulados imediatamente após sua elaboraçäo e a cada 30 dias. As duas formas de conservaçäo mostraram-se igualmente eficazes, mantendo os títulos hemaglutinantes dentro dos limites preconizados para a realizaçäo da prova de inibiçäo da hemaglutinaçäo. Este comportamento também foi verificado posteriormente, quando os antígenos foram estocados a -20 §C por 150 dias

Sensibilidade a violeta genciana de amostras de fungos do grupo Aspergillus flavus isolados de ingredientes e raçöes avícolas em Santa Catarina / Gentian violet sensitivity of Aspergillus flavus isolated from ingredients and poultry feed in Santa Catarina

Nove amostras de fungos do grupo Aspergillus flavus, isolados de ingredientes e raçöes avícolas em Santa Catarina, foram testadas para sua sensibilidade à violeta genciana. Os fungos foram cultivados em ágar, contendo extrato de côco da Bahia (33,3%) e o antifúngico em níveis de 0,1 até 819,2 ug/ml. Os fungos testados foram acompanhados pela amostra padräo Aspergillus parasiticus NRRL-2999 para a comparaçäo do diâmetro da colônia ao quinto dia de cultivo a 28§C. Todas as amostras apresentaram sensibilidade, porém em graus diferentes. Os níveis calculados de violeta genciana para a inibiçäo de 99% do crescimento das colônias variou de 375,1 até 2236,3 ug/ml