Plasmid-mediated quinolone resistance (PMQR) and mutations in the topoisomerase genes of Salmonella enterica strains from Brazil

The objective of this study was to identify mutations in the Quinolone Resistance Determining sources Regions (QRDR) of the gyrA, gyrB, parC, and parE genes and to determine if any of the qnr variants or the aac(6')-Ib-cr variant were present in strains of Salmonella spp. isolated in Brazil. A total of 126 Salmonella spp. strains from epidemic (n = 114) and poultry (n = 12) origin were evaluated. One hundred and twelve strains (88.8%) were resistant to nalidixic acid (NAL) and 29 (23.01%) showed a reduced susceptibility to ciprofloxacin (Cip). The mutations identified were substitutions limited to the QRDR of the gyrA gene in the codons for Serine 83, Aspartate 87 and Alanine 131. The sensitivity to NAL seems to be a good phenotypic indication of distinguishing mutated and nonmutated strains in the QRDR, however the double mutation in gyrA did not cause resistance to ciprofloxacin. The qnrA1 and qnrB19 genes were detected, respectively, in one epidemic strain of S. Enteritidis and one strain of S. Corvallis of poultry origin. Despite previous detection of qnr genes in Brazil, this is the first report of qnr gene detection in Salmonella, and also the first detection of qnrB19 gene in this country. The results alert for the continuous monitoring of quinolone resistance determinants in order to minimize the emergence and selection of Salmonella spp. strains showing reduced susceptibility or resistance to quinolones

Desenvolvimento inicial de clones IAC de seringueira em São José do Rio Preto, SP

In this study the development of four clones (IAC 35; 40; 300 e 301) of rubber tree [Hevea brasiliensis (Willd. ex A. Juss.) Müell. Arg.] selected by Instituto Agronômico de Campinas were evaluated during the first 24 months of cultivation. The experiment was laid out in randomized block design with three replications and four plants for parcel following the 1.5mx1.0m spacing at São José do Rio Preto, SP. The clone RRIM 600 was used as check. The variables analyzed were the trunk girth, the number of matured whorl, the photosynthesis rate and the concentrations of chlorophyll a, b, total and carotenoids. At the end of the experiment the values of trunk girth at 0.5m above the budgrafting union varied from 5.85 cm (IAC 301) to 10.53 cm (IAC 300) and the mean number of matured whorl varied from 2.58 (IAC 301) to 3.91 (RRIM 600). During the dry season, when the plants were 22 month old, the mean value of photosynthesis rate of IAC 40 and IAC 301 (12mol m-2 s-1) were lower compared to the other clones (15mol m-2 s-1). The chlorophyll a, b and total carotenoids concentrations were equal or superior to the check, never lower. Considering the variables analyzed, excluding the IAC 301, the other clones show performance comparable to RRIM 600.Neste estudo, acompanhou-se o desenvolvimento de quatro clones de seringueira [Hevea brasiliensis (Willd. ex A. Juss.) Müell. Arg.] selecionados pelo Instituto Agronômico de Campinas (IAC 35; 40; 300 e 301) com relação à testemunha RRIM 600, durante os primeiros 24 meses de cultivo. O experimento foi instalado com espaçamento 1,5x1,0m, em delineamento em blocos casualizados, com três repetições e quatro plantas por parcela, em São José do Rio Preto, SP. Foram avaliados o perímetro do caule e o número de lançamentos maduros; a taxa fotossintética e o conteúdo de pigmentos fotossintéticos. Ao final do acompanhamento, o perímetro médio do tronco, a 50cm do calo de enxertia, variou entre 5,85cm (IAC 301) e 10,53cm (IAC 300) e o número médio de lançamentos maduros, de 2,58 (IAC 301) a 3,91 (RRIM 600). No período seco, em idade de 22 meses após o plantio, os valores médios de taxa fotossintética de IAC 40 e IAC 301 (12mol m-2 s-1) foram inferiores aos dos demais clones (15mol m-2 s-1). Os teores de clorofila a, clorofila b e carotenoides totais foram iguais ou superiores aos da testemunha, mas nunca inferiores. Considerando as variáveis analisadas, com exceção do 301, os clones IAC mostram desempenho comparável ao do clone RRIM 600.Universidade Estadual Paulista Departamento de Zoologia e BotânicaUNESP Programa de Pós-graduação em Produção VegetalUniversidade Estadual Paulista Departamento de Zoologia e BotânicaUNESP Programa de Pós-graduação em Produção Vegeta