Ethanol induction of laccase depends on nitrogen conditions of Pycnoporus sanguineus

Background: Ethanol has been pointed out as a laccase inducer. However, there are controversial reports about its efficiencywith some fungi. In this study,we hypothesized that ethanol laccase induced in Pycnoporus sanguineus depends on nitrogen nutriment conditions. To prove this,we assessed laccase production in submerged cultures of P. sanguineus,with different nitrogen concentrations andwith, orwithout ethanol added in a factorial designed experiment. Results: In order to analyze the effects of factors on the response variables, a factorial ANOVA, and response-surface models were performed. It was found that the nitrogen source was the main factor that affected laccase production in P. sanguineus. The treatments with yeast extract (2 g/L) and ethanol (3 g/L) induced the highest laccase activity (31.01 \ub1 4.9 U/L), while the treatments with urea reached the lowest activity (less than 1.6 U/L). Ethanol had positive and synergic effects on laccase production, in accordance with the surface response model, as long as simple nitrogen sources (urea) were not available. Conclusions: We suggest that laccase in P. sanguineus is regulated by a catabolic nitrogen repressionmechanism; laccase activity is strongly inhibited by urea used as nitrogen source and it decreases when the amount of urea increases; contrarily, a synergic positive effect was observed between yeast extract and ethanol on laccase production

Aspiration risk factors, microbiology, and empiric antibiotics for patients hospitalized with community-acquired pneumonia

Background: Aspiration community-acquired pneumonia (ACAP) and community-acquired pneumonia (CAP) in patients with aspiration risk factors (AspRFs) are infections associated with anaerobes, but limited evidence suggests their pathogenic role. Research question: What are the aspiration risk factors, microbiology patterns, and empiric anti-anaerobic use in patients hospitalized with CAP? Study design and methods: This is a secondary analysis of GLIMP, an international, multicenter, point-prevalence study of adults hospitalized with CAP. Patients were stratified into three groups: (1) ACAP, (2) CAP/AspRF+ (CAP with AspRF), and (3) CAP/AspRF- (CAP without AspRF). Data on demographics, comorbidities, microbiological results, and anti-anaerobic antibiotics were analyzed in all groups. Patients were further stratified in severe and nonsevere CAP groups. Results: We enrolled 2,606 patients with CAP, of which 193 (7.4%) had ACAP. Risk factors independently associated with ACAP were male, bedridden, underweight, a nursing home resident, and having a history of stroke, dementia, mental illness, and enteral tube feeding. Among non-ACAP patients, 1,709 (70.8%) had CAP/AspRF+ and 704 (29.2%) had CAP/AspRF-. Microbiology patterns including anaerobes were similar between CAP/AspRF-, CAP/AspRF+ and ACAP (0.0% vs 1.03% vs 1.64%). Patients with severe ACAP had higher rates of total gram-negative bacteria (64.3% vs 44.3% vs 33.3%, P = .021) and lower rates of total gram-positive bacteria (7.1% vs 38.1% vs 50.0%, P 50% in all groups) independent of AspRFs or ACAP received specific or broad-spectrum anti-anaerobic coverage antibiotics. Interpretation: Hospitalized patients with ACAP or CAP/AspRF+ had similar anaerobic flora compared with patients without aspiration risk factors. Gram-negative bacteria were more prevalent in patients with severe ACAP. Despite having similar microbiological flora between groups, a large proportion of CAP patients received anti-anaerobic antibiotic coverage