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The antimicrobial actions of three common plant-derived terpenoids (i.e., carvacrol, thymol and eugenol) were compared to those of a typical quaternary ammonium biocide (i.e., benzalkonium chloride; BAC), against both planktonic and biofilm cells of two widespread Staphylococcus species (i.e., S. aureus and S. epidermidis). The minimum inhibitory and bactericidal concentrations (MICs, MBCs) of each compound against the planktonic cells of each species were initially determined, together with their minimum biofilm eradication concentrations (MBECs). Various concentrations of each compound were subsequently applied, for 6 min, against each type of cell, and survivors were enumerated by agar plating to calculate log reductions and determine the resistance coefficients (Rc) for each compound, as anti-biofilm effectiveness indicators. Sessile communities were always more resistant than planktonic ones, depending on the biocide and species. Although lower BAC concentrations were always needed to kill a specified population of either cell type compared to the terpenoids, for the latter, the required increases in their concentrations, to be equally effective against the biofilm cells with respect to the planktonic ones, were not as intense as those observed in the case of BAC, presenting thus significantly lower Rc. This indicates their significant anti-biofilm potential and advocate for their further promising use as anti-biofilm agents.

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Fresh vegetables and salads are increasingly implicated in outbreaks of foodborne infections, such as those caused by Listeria monocytogenes, a dangerous pathogen that can attach to the surfaces of the equipment creating robust biofilms withstanding the killing action of disinfectants. In this study, the antimicrobial efficiency of a natural plant terpenoid (thymol) was evaluated against a sessile population of a multi-strain L. monocytogenes cocktail developed on stainless steel surfaces incubated in lettuce broth, under optimized time and temperature conditions (54 h at 30.6 °C) as those were determined following response surface modeling, and in comparison, to that of an industrial disinfectant (benzalkonium chloride). Prior to disinfection, the minimum bactericidal concentrations (MBCs) of each compound were determined against the planktonic cells of each strain. The results revealed the advanced killing potential of thymol, with a concentration of 625 ppm (= 4 × MBC) leading to almost undetectable viable bacteria (more than 4 logs reduction following a 15-min exposure). For the same degree of killing, benzalkonium chloride needed to be used at a concentration of at least 20 times more than its MBC (70 ppm). Discriminative repetitive sequence-based polymerase chain reaction (rep-PCR) also highlighted the strain variability in both biofilm formation and resistance. In sum, thymol was found to present an effective anti-listeria action under environmental conditions mimicking those encountered in the salad industry and deserves to be further explored to improve the safety of fresh produce.

Objectives: Many people with dementia live in their home and require ongoing care, which is often provided by informal family caregivers. Thus, we examined the effectiveness of a multicomponent home-based intervention by evaluating its impact on a) neuropsychiatric symptoms of people with dementia and b) burden and depression of their caregivers. Methods: During the first 6 months of this prospective single-center study, we applied a home-based multicomponent intervention in 205 dyads of care-recipients and caregivers. In further analyzes, we included only dyads of caregivers and care-recipients with available data both at baseline and 6-month follow-up (N = 144). All assessments were conducted at home and included sociodemographic features, care-recipients’ clinical data, cognitive status (Mini-Mental State Examination), activities of daily living (Instrumental Activities of Daily Living; Katz Index of Independence in Activities of Daily Living), neuropsychiatric symptoms (Neuropsychiatric Inventory), and caregivers’ burden (Zarit Burden Inventory) and depression (Center for Epidemiological Studies-Depression). Results: We found significant decreases in the severity (pFDR = 0.002) and associated distress (pFDR = 0.001) of neuropsychiatric symptoms, as well as caregivers’ burden (pFDR = 0.004) and depressive symptoms (pFDR = 0.001). As expected, there was significant deterioration in care-recipients’ cognitive status (pFDR = 0.005) and measures of activities of daily living (pFDR < 0.005). Conclusion: Despite the progressive course of dementia, the home-based multicomponent intervention was effective in decreasing caregivers’ burden and depression and minimizing care-recipients’ neuropsychiatric symptoms’ severity and associated distress after 6 months. Our study highlights the establishment of home-based care units as an advantageous solution, specifically for family members seen to have a “taken-for-granted” role in dementia caring.