RESUMO
Antimicrobial resistance of Escherichia coli is a growing problem in both developed and developing countries. This study aimed to investigate the phenotypic antimicrobial resistance of E. coli isolates (n = 260) isolated from the stool specimen of patients attending public health facilities in Addis Ababa and Hossana. This study also aimed to characterize phenotypically confirmed extended-spectrum beta-lactamase (ESBL)-producing E. coli isolates (n = 22) using whole-genome sequencing. Resistance to 18 different antimicrobials was assessed using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The highest resistance rate among the E. coli isolates was found for ampicillin (52.7%), followed by trimethoprim-sulfamethoxazole (29.6%). Of all isolates, 50 (19.2%) were multidrug-resistant and 22 (8.5%) were ESBL producers. ESBL genes were detected in 94.7% of the sequenced E. coli isolates, and multiple ß-lactamase genes were detected in 57.9% of the isolates. The predominant ESBL gene identified was blaCTX-M-15 (78.9%). The blaTEM-1B gene was detected in combination with other ESBL genes in 57.9% of the isolates, while only one of the sequenced isolates contained the blaTEM-1B gene alone. The blaCTX-M-3 gene was detected in three isolates. The genes blaCTX-M-15 and blaTEM-1B as well as blaCTX-M-15 and blaTEM-169 were confirmed to coexist in 52.6% and 10.5% of the sequenced E. coli isolates, respectively. In addition, blaOXA-1 was identified together with blaCTX-M-15 and blaTEM-1B in one isolate, and in one isolate, blaTEM-169 together with blaCTX-M-15 and blaTEM-1B was found. The results obtained show that measures need to be taken to reduce the spread of drug resistance and ensure the long-term use of available antimicrobials.
RESUMO
Olive leaf extract (OLE) is used in traditional medicine as a food supplement and as an over-the-counter drug for a variety of its effects, including anti-inflammatory and anti-atherosclerotic ones. Mechanisms through which OLE could modulate these pathways in human vasculature remain largely unknown. Serum amyloid A (SAA) plays a causal role in atherosclerosis and cardiovascular diseases and induces pro-inflammatory and pro-adhesive responses in human coronary artery endothelial cells (HCAEC). Within this study we explored whether OLE can attenuate SAA-driven responses in HCAEC. HCAEC were treated with SAA (1,000 nM) and/or OLE (0.5 and 1 mg/ml). The expression of adhesion molecules VCAM-1 and E-selectin, matrix metalloproteinases (MMP2 and MMP9) and microRNA 146a, let-7e, and let-7g (involved in the regulation of inflammation) was determined by qPCR. The amount of secreted IL-6, IL-8, MIF, and GRO-α in cell culture supernatants was quantified by ELISA. Phosphorylation of NF-κB was assessed by Western blot and DNA damage was measured using the COMET assay. OLE decreased significantly released protein levels of IL-6 and IL-8, as well as mRNA expression of E-selectin in SAA-stimulated HCAEC and reduced MMP2 levels in unstimulated cells. Phosphorylation of NF-κB (p65) was upregulated in the presence of SAA, with OLE significantly attenuating this SAA-induced effect. OLE stabilized SAA-induced upregulation of microRNA-146a and let-7e in HCAEC, suggesting that OLE could fine-tune the SAA-driven activity of NF-κB by changing the microRNA networks in HCAEC. SAA induced DNA damage and worsened the oxidative DNA damage in HCAEC, whereas OLE protected HCAEC from SAA- and H2O2-driven DNA damage. OLE significantly attenuated certain pro-inflammatory and pro-adhesive responses and decreased DNA damage in HCAEC upon stimulation with SAA. The reversal of SAA-driven endothelial activation by OLE might contribute to its anti-inflammatory and anti-atherogenic effects in HCAEC.