Fate of non O157 Shigatoxigenic Escherichia coli in ovine manure composting / Eliminação de Escherichia coli Shigatoxigênica não O157 em compostagem de esterco ovino

Livestock manure may contain pathogenic microorganisms which pose a risk to the health of animal or humans if the manure is not adequately treated or disposed of. To determine the fate of Shiga toxigenic Escherichia coli (STEC) non O157 in composted manure from naturally colonized sheep, fresh manure was obtained from animals carrying bacterial cells with stx1/ stx2 genes. Two composting systems were used, aerated and non-aerated, and the experiments were done in Dracena city, São Paulo State. Every week, for seven weeks, one manure sample from six different points in both systems was collected and cultured to determine the presence of E. coli, the presence of the virulence genes in the cells, and also the susceptibility to 10 antimicrobial drugs. The temperature was verified at each sampling. STEC non-O157 survived for 49 days in both composting systems. E. coli non-STEC showing a high degree of antibiotic resistance was recovered all long the composting period. No relationship was established between the presence of virulence genes and antibiotic resistance. The presence of virulence genes and multiple antibiotic resistances in E. coli implicates a potential risk for these genes spread in the human food chain, which is a reason for concern...

Esterco de animais de criação pode conter microrganismos patogênicos, o que representa um risco para a saúde animal e a humana se o esterco não for adequadamente tratado ou descartado. Determinou-se o tempo necessário para a eliminação de Escherichia coli Shiga toxigenica (STEC) não O157 em esterco ovino composto, obtido de fezes frescas de ovelhas naturalmente colonizadas com cepas STEC não O157 que apresentavam os genes stx1/ stx2. Foram utilizados dois sistemas de compostagem, aerado e não aerado, em experimentos realizados na cidade de Dracena, estado de São Paulo. Todas as semanas, durante sete semanas, uma amostra de compostagem proveniente de seis pontos diferentes na leira, nos dois sistemas, foi coletada e semeada para a determinação da presença de E. coli, da presença de genes de virulência nas células, bem como da sensibilidade dessas células a 10 drogas antimicrobianas. Em cada amostragem, a temperatura da leira foi analisada. Células de STEC não O157 sobreviveram por 49 dias nos dois sistemas de compostagem. E. coli não STEC com um alto grau de resistência a antibióticos foi recuperada ao longo de todo o período de compostagem. Não foi possível estabelecer relação entre a presença de genes de virulência e a resistência a antibióticos. A presença de genes de virulência e a resistência a múltiplos antibióticos em E. coli representam um risco potencial para o espalhamento desses genes na cadeia alimentar humana, o que é motivo de grande preocupação...

Induction of Fos protein immunoreactivity by spinal cord contusion

The objective of the present study was to identify neurons in the central nervous system that respond to spinal contusion injury in the rat by monitoring the expression of the nuclear protein encoded by the c-fos gene, an activity-dependent gene, in spinal cord and brainstem regions. Rats were anesthetized with urethane and the injury was produced by dropping a 5-g weight from 20.0 cm onto the exposed dura at the T10-L1 vertebral level (contusion group). The spinal cord was exposed but not lesioned in anesthetized control animals (laminectomy group); intact animals were also subjected to anesthesia (intact control). Behavioral alterations were analyzed by Tarlov/Bohlman scores, 2 h after the procedures and the animals were then perfused for immunocytochemistry. The patterns of Fos-like immunoreactivity (FLI) which were site-specific, reproducible and correlated with spinal laminae that respond predominantly to noxious stimulation or injury: laminae I-II (outer substantia gelatinosa) and X and the nucleus of the intermediolateral cell column. At the brain stem level FLI was detected in the reticular formation, area postrema and solitary tract nucleus of lesioned animals. No Fos staining was detected by immunocytochemistry in the intact control group. However, detection of FLI in the group submitted to anesthesia and surgical procedures, although less intense than in the lesion group, indicated that microtraumas may occur which are not detected by the Tarlov/Bohlman scores. There is both a local and remote effect of a distal contusion on the spinal cord of rats, implicating sensory neurons and centers related to autonomic control in the reaction to this kind of injury.