RESUMO
A newly isolated amylolytic strain was identified as Bacillus cereus spH1 based on 16S and 16-23S gene sequencing (Accession numbers OP811441.1 and OP819558, respectively), optimization strategies, using one variable at time (OVAT) and Plackett-Burman design, were employed to improve the alpha-amylase (α-amylase) production. Condition inferred revealed that the optimal physical parameters for maximum enzyme production were 30 °C, pH 7.5, and 12 h of incubation, using tryptone, malt extract, orange (Citrus sinensis) peels, crab (Portunus segnis) shells, calcium, and sodium chloride (NaCl) as culture medium. The full factorial design (FFD) model was observed to possess a predicted R2 and adjusted R2 values of 0.9788 and 0.9862, respectively, and it can effectively predict the response variables (p = 0). Following such efforts, α-amylase activity was increased 141.6-folds, ranging from 0.06 to 8.5 U/mL. The ideal temperature and pH for the crude enzyme activity were 65 °C and 7.5, respectively. The enzyme exhibited significant stability, with residual activity over 90% at 55 °C. The maltose was the only product generated during the starch hydrolysis. Moreover, the Bacillus cereus spH1 strain and its α-amylase were used in the treatment of effluents from the pasta industry. Germination index percentages of 143% and 139% were achieved when using the treated effluent with α-amylase and the strain, respectively. This work proposes the valorization of agro-industrial residues to improve enzyme production and to develop a green and sustainable approach that holds great promise for environmental and economic challenges.
RESUMO
Background: Infective endocarditis is a rare condition in childhood, and there is limited data on this disease in Tunisia. Objective: This study aims to analyze the epidemiological profile, bacteriological data, and prognosis of infective endocarditis in children admitted to the pediatric department of a University Hospital in Tunisia. Methods: We conducted a comparative cross-sectional study in the pediatric department of Sahloul Teaching Hospital in Sousse, a tertiary referral hospital in Tunisia. The study included all children aged ≤ 18 years with infective endocarditis admitted to the tertiary referral center for pediatrics in Sahloul University Hospital from January 1994 to December 2022. The diagnosis of infective endocarditis was based on modified Duke's criteria. Results: Thirty-six patients met the diagnostic criteria for infective endocarditis, resulting in a proportion of 07 cases per 1000 hospital admissions. The mean age was 6 years (range: 40 days to 16 years). Congenital heart disease was identified as the underlying lesion in 23 cases (63.9 %). Blood cultures were positive in 20 patients (55.6 %), predominantly with Staphylococcus species (55 %). The most frequent complications involved the central nervous system (8 cases; 22.2 %). The mortality rate was 25 %, and factors predicting mortality included heart failure on admission or during the hospital stay, increased leukocyte count, and decreased prothrombin time. Conclusion: Our study reveals a shift in the prevalent underlying lesions, with rheumatic heart diseases no longer being the most common. Staphylococcus spp. emerged as the predominant organism in blood cultures. Notably, mortality predictors included heart failure, an elevated leukocyte count, and a decreased prothrombin time rate.