1. Investigación

The widespread irrational use of antibiotics in recent years has resulted in an increase in the detection of multi-resistant bacterial strains, particularly methicillin-resistant Staphylococcus aureus (MRSA). The use of natural derivatives such as flavonoids is postulated as one of the most promising avenues to solve this emerging public health problem. The objective of the present study is to characterize the antimicrobial activity of icariin, a flavonoid compound isolated from a variety of plants of the Epimedium genus, against human and animal clinical MRSA isolates. Our study found that icariin alone did not have any antimicrobial effect on S. aureus or MRSA clinical isolates. However, icariin enhanced the effect of amoxycillin-clavulanate or ampicillin, whereas no effect was seen when used in combination with vancomycin. Specifically, co-incubation of S. aureus with amoxycillin-clavulanate plus icariin resulted in an increased proportion of dead cells, suggesting that this flavonoid potentially increases antimicrobial activity when used in combination with the beta-lactam antibiotic amoxycillin-clavulanate. Furthermore, we demonstrate that co-incubation of S. aureus with AmoxyClav plus icariin resulted in increased membrane disruption and growth inhibition. This study demonstrates the potential utility of icariin in permitting lower antibiotic therapeutic doses in alignment with strategies to reduce the spread of antibiotic resistance. Further research is required to determine the optimum concentration of icariin and to define clinically relevant combinations of flavonoid and antibiotic.

Neonatal sepsis is a serious condition, where an adequate empiric antibiotic treatment is crucial. The objective of this systematic review is to assess whether the World Health Organization’s recommended treatment regime remains applicable for late-onset neonatal sepsis caused by Enterobacteriaceae, in the time of increased antimicrobial resistance. PubMed was searched for articles from 2009 to 2020. A total of 49 articles were eligible for inclusion. The review was carried out in accordance with PRISMA guidelines. For Klebsiella spp. 100, 68 and 63% of the studies found sensitivity to ampicillin, gentamicin and third-generation cephalosporin in <50% of the isolates. For Escherichia coli, the corresponding values were 88, 50 and 42% respectively, whilst for Enterobacter spp. 100, 70 and 94% of the studies found <50% sensitivity to these antibiotics. Overall, there is low sensitivity to all agents in the WHO’s recommended empiric treatment regimes (WHO recommends ampicillin plus gentamicin as first-line treatment and third-generation cephalosporin as second-line treatment). A revised guideline for empiric antibiotic treatment of neonatal sepsis is urgently needed due to the increased threat of antimicrobial resistant Enterobacteriaceae causing neonatal sepsis.