RESUMO
To investigate antimicrobial resistance, 96 Salmonella enterica subspecies enterica serovar Enteritidis strains isolated from salmonellosis outbreaks and poultry-related products obtained in southern Brazil were analyzed. Macrorestriction patterns, obtained by pulsed-field gel electrophoresis and phage types, were assessed. Although 43.75% of samples were sensitive to all drugs tested, resistance to sulfonamide (34.37%), trimethoprim-sulfamethoxazole (25.00%), nalidixic acid (14.58%), streptomycin (2.08%), gentamicin, and tetracycline (1.04%) was identified. Furthermore, 89.60% of strains belonged to phage type 4, and a predominant pulsed-field gel electrophoresis genotype represented by 82.29% of the strains was identified, suggesting that a clonal group was distributed in poultry, food, and human isolates. Although it was not possible to associate strains from different sources, the occurrence of antimicrobial-resistant Salmonella Enteritidis strains supports the need to establish monitoring programs to identify the emergence of potential resistance patterns and to direct policies for use of these drugs in food-producing animals.
Assuntos
Antibacterianos/farmacologia , Surtos de Doenças/veterinária , Farmacorresistência Bacteriana Múltipla , Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Infecções por Salmonella/microbiologia , Salmonella enteritidis/isolamento & purificação , Animais , Tipagem de Bacteriófagos , Brasil/epidemiologia , DNA Bacteriano/química , DNA Bacteriano/genética , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Fragmento de Restrição , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/epidemiologia , Salmonelose Animal/tratamento farmacológico , Salmonelose Animal/epidemiologia , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genéticaRESUMO
Missing data is a recurrent issue in epidemiology where the infection process may be partially observed. Approximate Bayesian computation (ABC), an alternative to data imputation methods such as Markov chain Monte Carlo (MCMC) integration, is proposed for making inference in epidemiological models. It is a likelihood-free method that relies exclusively on numerical simulations. ABC consists in computing a distance between simulated and observed summary statistics and weighting the simulations according to this distance. We propose an original extension of ABC to path-valued summary statistics, corresponding to the cumulated number of detections as a function of time. For a standard compartmental model with Suceptible, Infectious and Recovered individuals (SIR), we show that the posterior distributions obtained with ABC and MCMC are similar. In a refined SIR model well suited to the HIV contact-tracing data in Cuba, we perform a comparison between ABC with full and binned detection times. For the Cuban data, we evaluate the efficiency of the detection system and predict the evolution of the HIV-AIDS disease. In particular, the percentage of undetected infectious individuals is found to be of the order of 40%.
Assuntos
Busca de Comunicante , Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , Modelos Biológicos , Algoritmos , Teorema de Bayes , Simulação por Computador , Cuba/epidemiologia , Humanos , Modelos Lineares , Cadeias de Markov , Método de Monte Carlo , Dinâmica não Linear , Processos EstocásticosRESUMO
The iron oxyallyl carbocation generated from 2,7-dibromocycloheptanone was induced to undergo [4 + 3] cycloaddition reactions with various furans, affording a series of 12-oxatricyclo-[4.4.1.1(2,5)]-dodec-3-en-11-one adducts. Similar methodology was used to prepare two additional cycloadducts using menthofuran and two homologous aliphatic dibromoketones. Dipolar cycloaddition of ozone to the adducts afforded the corresponding secondary ozonides (i.e., 1,2,4-trioxolanes) in variable yields. Ozonides were investigated by quantum mechanics at the B3LYP/6-31+G* level to study structural features including close contacts which may be responsible for enhancing ozonide stability. The effect of these ozonides and their corresponding precursor cycloadducts upon radicle growth of both Sorghum bicolor and Cucumis sativus was evaluated at 5.0 x 10(-4) mol L(-1). The most active cycloadducts and ozonides were also evaluated against the weed species Ipomoea grandifolia and Brachiaria decumbens, and the results are discussed. Compared to ozonides previously synthesized in our laboratory, the new ozonides described herein present improved plant growth regulatory activity.
Assuntos
Cucumis sativus/crescimento & desenvolvimento , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/farmacologia , Sorghum/crescimento & desenvolvimento , Cucumis sativus/efeitos dos fármacos , Compostos Heterocíclicos/química , Sorghum/efeitos dos fármacosRESUMO
During a study on Salmonella enterica subsp. enterica serovar Derby from slaughter-age pigs in Brazil, two epidemiologically unrelated multi-resistant S. Derby isolates were found to carry a class 1 integron with a single gene cassette. Sequence analysis confirmed that this gene cassette harboured an aadA2 gene. The aadA2 gene codes for an aminoglycoside adenyltransferase, which mediates resistance to the aminoglycoside streptomycin and the aminocyclitol spectinomycin. Although aadA2 gene cassettes are widely distributed among Salmonella, database searches identified an AadA2 protein indistinguishable from that of S. Derby only in single isolates of S. enterica subsp. enterica Enteritidis from France and S. enterica subsp. enterica Typhimurium from Japan. Structural analysis of the 59-base element revealed at least one base pair difference between the 59-base element of the aadA2 cassette from S. Derby and any of the 59-base elements deposited in the databases.