Irrigation Ponds as Sources of Antimicrobial-Resistant Bacteria in Agricultural Areas with Intensive Use of Poultry Litter

Poultry litter is widely used worldwide as an organic fertilizer in agriculture. However, poultry litter may contain high concentrations of antibiotics and/or antimicrobial-resistant bacteria (ARB), which can be mobilized through soil erosion to water bodies, contributing to the spread of antimicrobial resistance genes (ARGs) in the environment. To better comprehend this kind of mobilization, the bacterial communities of four ponds used for irrigation in agricultural and poultry production areas were determined in two periods of the year: at the beginning (low volume of rainfall) and at the end of the rainy season (high volume of rainfall). 16S rRNA gene sequencing revealed not only significantly different bacterial community structures and compositions among the four ponds but also between the samplings. When the DNA obtained from the water samples was PCR amplified using primers for ARGs, those encoding integrases (intI1) and resistance to sulfonamides (sul1 and sul2) and β-lactams (blaGES, blaTEM and blaSHV) were detected in three ponds. Moreover, bacterial strains were isolated from CHROMagar plates supplemented with sulfamethoxazole, ceftriaxone or ciprofloxacin and identified as belonging to clinically important Enterobacteriaceae. The results presented here indicate a potential risk of spreading ARB through water resources in agricultural areas with extensive fertilization with poultry litter

A Psicologia Evolucionista e os domínios da cognição social

O estudo da cognição social começou a ter destaque com o surgimento da Psicologia Cognitiva no final dos anos 60 e início dos anos 70. A expressão refere-se aos processos que orientam o comportamento diante de outros indivíduos. Este trabalho analisa uma nova abordagem da cognição social baseada na Psicologia Evolucionista. Os autores descrevem alguns aspectos relacionados à filogênese da cognição humana. A revisão bibliográfica desta pesquisa considerou livros e artigos sobre o tema publicados no período de 1975 a 2006. O artigo explica também os principais mecanismos que se apresentam como produtos da seleção natural e que surgiram para resolver problemas da vida social na história evolutiva humana. Na parte final, discute-se a importância desse novo enfoque