Prophylactic administration of Withania somnifera extract increases host resistance in Listeria monocytogenes infected mice

In this study, we demonstrated that Withania somnifera L. extract (WSE) protects mice from a lethal dose of Listeria monocytogenes when administered prophylactically at 100, 250 and 500 mg/kg for 10 days, with survival rates up to 30%. These doses also prevented the myelosuppression and the splenomegaly caused by a sublethal infection with L. monocytogenes, due to increased numbers of granulocyte-macrophage progenitors (CFU-GM) in the bone marrow. Investigation of the production of colony-stimulating factors (CSFs) revealed increased colony-stimulating activity (CSA) in the serum of normal and infected mice pre-treated with WSE. Further studies to investigate the levels of interferon-gamma (INF-gamma) and lymphocyte cell proliferation were undertaken. We observed dose-dependent increases in cell proliferation and in the levels of INF-gamma in mice infected with L. monocytogenes and treated with WSE. All together, our results suggest that WSE indirectly modulates immune activity and probably disengages Listeria-induced suppression of these responses by inducing a higher reserve of myeloid progenitors in the bone marrow, proliferation of lymphocytes and increased INF-gamma levels. (c) 2006 Elsevier B.V. All rights reserved.6101535154

Early-onset bacterial infection in Brazilian neonates with respiratory distress: A hospital-based study

We investigated infants with respiratory distress within 4 days of birth whose mothers had not received antibiotic prophylaxis to evaluate the frequency and etiology of bacterial infection and associated risk factors. the study was conducted on 261 infants suffering respiratory distress admitted to a Brazilian neonatal intensive care unit, 94 per cent of whom were born prematurely. Gestational and delivery history; bacteriological cultures of blood, cerebrospinal fluid, tracheal aspirates and urine; complete and differential blood counts; a urinary group B streptococcal latex antigen test; and a chest radiograph were analysed. Indications of infection were found in 38.7 per cent and confirmed in 11.9 per cent of the neonates. Gram-positive (70.9 per cent) and Gram-negative bacteria (29.1 per cent) were found in 31 cases of confirmed early bacteremia. Group B Streptococcus was the predominant causative agent (19.4 per cent) in infants exhibiting confirmed infection. Culture-proven infection was more frequent among infants delivered vaginally (adjusted OR = 2.53,p = 0.05) or born to mothers with signs of intra-amniotic infection (adjusted OR = 2.83, p = 0.04). Preventive measures against early bacterial infection in preterm infants from this population are strongly warranted.Univ São Paulo, Fac Med Ribeirao Preto, Dept Pediat, São Paulo, BrazilWeb of Scienc