Donepezil (DPZ) is widely used in the treatment of Alzheimer’s disease in tablet form for oral administration. The pharmacological efficacy of this drug can be enhanced by the use of intranasal administration because this route makes bypassing the blood–brain barrier (BBB) possible. The aim of this study was to develop a nanoemulsion (NE) as well as a nanoemulsion with a combination of bioadhesion and penetration enhancing properties (PNE) in order to facilitate the transport of DPZ from nose-to-brain. Composition of NE was established using three pseudo-ternary diagrams and PNE was developed by incorporating Pluronic F-127 to the aqueous phase. Parameters such as physical properties, stability, in vitro release profile, and ex vivo permeation were determined for both formulations. The tolerability was evaluated by in vitro and in vivo models. DPZ-NE and DPZ-PNE were transparent, monophasic, homogeneous, and physically stable with droplets of nanometric size and spherical shape. DPZ-NE showed Newtonian behavior whereas a shear thinning (pseudoplastic) behavior was observed for DPZ-PNE. The release profile of both formulations followed a hyperbolic kinetic. The permeation and prediction parameters were significantly higher for DPZ-PNE, suggesting the use of polymers to be an effective strategy to improve the bioadhesion and penetration of the drug through nasal mucosa, which consequently increase its bioavailability.

Escherichia coli Nissle 1917 (EcN) is a probiotic used in the treatment of intestinal diseases. Although it is considered safe, EcN is closely related to the uropathogenic E. coli strain CFT073 and contains many of its predicted virulence elements. Thus, it is relevant to assess whether virulence-associated genes are functional in EcN. One of these genes encodes the secreted autotransporter toxin (Sat), a member of the serine protease autotransporters of Enterobacteriaceae (SPATEs) that are secreted following the type V autotransporter pathway. Sat is highly prevalent in certain E. coli pathogenic groups responsible for urinary and intestinal infections. In these pathogens Sat promotes cytotoxic effects in several lines of undifferentiated epithelial cells, but not in differentiated Caco-2 cells. Here we provide evidence that sat is expressed by EcN during the colonization of mouse intestine. The EcN protein is secreted as an active serine protease, with its 107 kDa-passenger domain released into the medium as a soluble protein. Expression of recombinant EcN Sat protein in strain HB101 increases paracellular permeability to mannitol in polarized Caco-2 monolayers. This effect, also reported for the Sat protein of diffusely adherent E. coli, is not observed when this protein is expressed in the EcN background. In addition, we show that EcN supernatants confer protection against Sat-mediated effects on paracellular permeability, thus indicating that other secreted EcN factors are able to prevent barrier disruption caused by pathogen-related factors. Sat is not required for intestinal colonization, but the EcNsat::cat mutant outcompetes wild-type EcN in the streptomycin-treated mouse model. Analysis of the presence of sat in 29 strains of the ECOR collection isolated from stools of healthy humans shows 34.8 % positives, with high prevalence of strains of the phylogenetic groups D and B2, related with extra-intestinal infections. Sat does not act as a virulence factor in EcN. The role of Sat in intestinal pathogenesis relies on other genetic determinants responsible for the bacterial pathotype.

(1) Background: Alternative antibiotics are needed to treat infective endocarditis (IE) caused by non-faecalis/non-faecium enterococci; we aimed to assess the in vitro activity of ampicillin plus ceftriaxone (AMP + CTR) against these enterococci and to describe its clinical efficacy in IE cases. (2) Methods: Time–kill curves with standard (ISI) and high (IHI) inocula were performed to test VanC isolates [3 E. casseliflavus (ECAS) and 1 E. gallinarum (EGALL)] and non-VanC isolates [1 E. durans (EDUR), 1 E. hirae (EHIR) and 1 E. raffinosus (ERAF)]. The narrative literature review of IE cases treated with AMP + CTR was analyzed alongside three study cases. Clinical outcomes were relapse and death. (3) Results: Ampicillin plus gentamicin (AMP + GEN) showed synergistic and bactericidal activity against most isolates. AMP + CTR was synergistic at ISI for EGALL, EDUR, and EHIR and bactericidal against EHIR. At IHI, indifferent activity was observed for all isolates. In IE cases treated with AMP + CTR, it was only effective for EDUR and EHIR. Clinical information for EGALL IE is lacking. For IE caused by ECAS and ERAF, AMP + CTR seems suboptimal or ineffective, respectively. (4) AMP + CTR cannot be recommended for treating IE due to ECAS/ERAF. In contrast, this combination was effective in IE caused by EDUR/EHIR and could be recommended.

Objectives: Effective alternatives to standard of care treatment for E. faecalis infective endocarditis (EFIE) are needed. Some in vitro studies have suggested daptomycin and ceftaroline have synergistic activity against E. faecalis. We aimed to assess the in vitro and in vivo activity of daptomycin in combination with ceftaroline against E. faecalis clinical isolates with and without high-level of aminoglycoside resistance (HLAR). Materials and methods: A panel of six endocarditis-associated E. faecalis isolates were used for time–kill assays at initial standard and high inocula. Daptomycin (10 mg/kg/day intravenously) and daptomycin (10 mg/kg/day iv) plus ceftaroline (600 mg q12 hours intravenous) were compared in vivo using a human-like pharmacokinetic model in two treatment groups using the experimental EFIE model in rabbits. Results: The combination of daptomycin plus ceftaroline achieved synergy against all three HLAR and all three non-HLAR strains in time–kill assays at initial standard inoculum. A bactericidal effect was observed in two of the three HLAR E. faecalis isolates. For HLAR EFAE-188, the use of daptomycin plus ceftaroline significantly decreased the bacterial density in vegetations compared with daptomycin alone (median density 5.2 versus 6.7 log10 cfu/g; P = 0.028). For non-HLAR EFAE-468, the bacterial density in vegetations was lower with the combination therapy than with daptomycin alone (median density 5.2 versus 6.8 log10 cfu/g; P = 0.072). Adding ceftaroline prevented the development of daptomycin-resistant E. faecalis isolates in all cases. Conclusions: Daptomycin plus ceftaroline represents a promising alternative for treating EFIE. Further clinical studies are needed to confirm these findings.

Background: Positron emission tomography (PET) is a valuable tool in the diagnosis of cardiovascular infections. However, increased radiotracer uptake can also be observed in non-infectious inflammatory processes, leading to potential false positives. This study analyzed the uptake related to left atrial appendage closure devices (LAACD—AtriClip^®) to determine its association with infectious or inflammatory processes. Methods: We retrospectively analyzed 28 PET/CT scans from 20 patients with implanted LAACDs: 24 using ¹⁸F-fluorodeoxyglucose (FDG) and 4 using ¹⁸F-Choline (CHO). Clinical, laboratory, and imaging data were reviewed, and PET uptake was measured semi-quantitatively. All patients had at least 12 months of follow-up after PET imaging to assess for evidence of device-related infection. Results: Homogeneous PET uptake in the LAACD was observed in 93% (26/28) of the PET studies, regardless of the radiotracer used, clinical indication, or time since implantation. Clinical follow-up and laboratory findings revealed no signs of infection related to the LAACD in any case. SUV ratios did not differ significantly between the three PET indication groups (infection, neoplasia, or other; p = 0.46), nor between scans performed in patients with and without other confirmed infections unrelated to the LAACD (p = 0.37). Conclusions: FDG and CHO uptake in LAACDs appears to be a consistent and reproducible finding, most likely reflecting a sterile inflammatory response postoperative inflammatory uptake rather than true infection. Clear recognition of this uptake pattern is important to prevent misinterpretation and reduce the risk of false-positive PET/CT results in patients evaluated for suspected cardiovascular infections.

Background: Infective endocarditis (IE) is a severe infection mainly caused by Staphylococcus aureus, Enterococcus faecalis and viridans streptococci. Coagulase-negative staphylococci (CoNS), especially methicillin-resistant Staphylococcus epidermidis (MRSE), are major pathogens in prosthetic valves and devices. Exebacase is a first-in-class, antistaphylococcal lysin with rapid bactericidal and antibiofilm activity. Objective: To assess the in vitro activity of exebacase and standard IE antibiotics against S. aureus and CoNS isolates from IE patients in a university hospital (2010–2020). Methods: A total of 211 consecutive strains were analysed: S. aureus [n = 103 (82 MSSA, 21 MRSA)], S. epidermidis [n = 76 (20 MSSE, 56 MRSE)] and other CoNS species (n = 32, Staphylococcus haemolyticus, Staphylococcus lugdunensis, Staphylococcus hominis, Staphylococcus capitis, Staphylococcus schleiferi, Staphylococcus caprae, Staphylococcus pasteuri). Broth microdilution MICs were determined for exebacase and comparators (cloxacillin, ceftaroline, vancomycin, daptomycin, gentamicin, rifampicin). Results: Exebacase inhibited all S. aureus at ≤1 mg/L. Geometric mean (GM) MICs were 0.56 mg/L for MSSA and 0.49 mg/L for MRSA, with MIC50/90 of 0.5/1 mg/L. For S. epidermidis, GM MICs were 3.03 mg/L (MSSE) and 3.40 mg/L (MRSE), with MIC50/90 of 4/16 and 4/8 mg/L, respectively. Other CoNS showed GM MICs ranging from 0.49 mg/L (S. capitis) to 2.59 mg/L (S. lugdunensis), with intermediate values for S. haemolyticus (1.15), S. hominis (1.0) and S. schleiferi (0.79). Exebacase activity was comparable to β-lactams, vancomycin and daptomycin and remained unaffected by resistance. Conclusions: Exebacase activity was independent of methicillin resistance and consistently higher against S. aureus than S. epidermidis. Further research is warranted to explore lysins in combination against staphylococcal infections.