Biodeterioration of cultural heritage is caused by different organisms capable of inducing complex alteration processes. The present study aimed to evaluate the efficiency of Rosmarinus officinalis hydro-alcoholic extract to inhibit the growth of deteriogenic microbial strains. For this, the physico-chemical characterization of the vegetal extract by UHPLC–MS/MS, its antimicrobial and antibiofilm activity on a representative number of biodeteriogenic microbial strains, as well as the antioxidant activity determined by DPPH, CUPRAC, FRAP, TEAC methods, were performed. The extract had a total phenol content of 15.62 ± 0.97 mg GAE/mL of which approximately 8.53% were flavonoids. The polyphenolic profile included carnosic acid, carnosol, rosmarinic acid and hesperidin as major components. The extract exhibited good and wide spectrum antimicrobial activity, with low MIC (minimal inhibitory concentration) values against fungal strains such as Aspergillus clavatus (MIC = 1.2 mg/mL) and bacterial strains such as Arthrobacter globiformis (MIC = 0.78 mg/mL) or Bacillus cereus (MIC = 1.56 mg/mL). The rosemary extract inhibited the adherence capacity to the inert substrate of Penicillium chrysogenum strains isolated from wooden objects or textiles and B. thuringiensis strains. A potential mechanism of R. officinalis antimicrobial activity could be represented by the release of nitric oxide (NO), a universal signalling molecule for stress management. Moreover, the treatment of microbial cultures with subinhibitory concentrations has modulated the production of microbial enzymes and organic acids involved in biodeterioration, with the effect depending on the studied microbial strain, isolation source and the tested soluble factor. This paper reports for the first time the potential of R. officinalis hydro-alcoholic extract for the development of eco-friendly solutions dedicated to the conservation/safeguarding of tangible cultural heritage.

This study aims to demonstrate the effectiveness of silver nanoparticles (Ag NPs) on multidrug-resistant (MDR) Acinetobacter baumannii (AB) strains isolated from the clinical and aquatic environment. Three types of Ag NPs were investigated for their antimicrobial, antibiofilm, and antivirulence properties on a total number of 132 AB strains isolated in the same temporal sequence from intra-hospital infections (IHIs), wastewater (WW), and surface water (SW) samples between 2019 and 2022 from different Romanian locations and characterized at the phenotypic and genotypic levels. The comparative analysis of the antimicrobial resistance (AR) profiles according to the isolation source and the geographical location demonstrated a decrease in MDR level in AB recovered from WW samples in 2022 from north-eastern/central/southern regions (N-E/C-W/analyzed strains S): 87.5/60/32.5%. The AB strains were lecithinase, caseinase, amylase, and lipase producers, had variable biofilm formation ability, and belonged to six genotypes associated with the presence of different virulence genes (ompA, csuE, bap, and bfmS). The Ag NPs synthesized with the solvothermal method exhibited an inhibitory effect on microbial growth, the adherence capacity to the inert substratum, and on the production of soluble virulence factors. We report here the first description of a powerful antibacterial agent against MDR AB strains circulating between hospitals and anthropically polluted water in Romania.

Background: This study aimed to determine, at the phenotypic and molecular levels, resistance and virulence markers in Candida spp. isolated from community-acquired infections in Bucharest outpatients during 2021, and to demonstrate the efficiency of alternative solutions against them based on silver nanoparticles (AgNPs). Methods: A total of 62 Candida spp. strains were isolated from dermatomycoses and identified using chromogenic culture media and MALDI-TOF MS, and then investigated for their antimicrobial resistance and virulence markers (VMs), as well as for metabolic enzymes using enzymatic tests for the expression of soluble virulence factors, their biofilm formation and adherence capacity on HeLa cells, and PCR assays for the detection of virulence markers and the antimicrobial activity of alternative solutions based on AgNPs. Results: Of the total of 62 strains, 45.16% were Candida parapsilosis; 29.03% Candida albicans; 9.67% Candida guilliermondii; 3.22% Candida lusitaniae, Candia pararugosa, and Candida tropicalis; and 1.66% Candida kefyr, Candida famata, Candida haemulonii, and Candida metapsilosis. Aesculin hydrolysis, caseinase, and amylase production were detected in the analyzed strains. The strains exhibited different indices of adherence to HeLa cells and were positive in decreasing frequency order for the LIP1, HWP1, and ALS1,3 genes (C. tropicalis/C. albicans). An inhibitory effect on microbial growth, adherence capacity, and on the production of virulence factors was obtained using AgNPs. Conclusions: The obtained results in C. albicans and Candida non-albicans circulating in Bucharest outpatients were characterized by moderate-to-high potential to produce VMs, necessitating epidemiological surveillance measures to minimize the chances of severe invasive infections.

Background/Objectives: This study aims to characterize antibiotic resistance (AR) and virulence markers in Salmonella spp. isolated from Romanian outpatients’ stool samples. Methods: In 2019, community-acquired Salmonella strains were collected and identified using MALDI-TOF mass spectrometry, antibiotic susceptibility profiles have been determined with the MicroScan system, and soluble virulence factors were evaluated using specific culture media, while biofilm formation was quantified in 96-well plates. Molecular analysis targeted resistance genes for β-lactams (e.g., bla_TEM and bla_SHV); tetracyclines (e.g., tet(A)); sulphonamides; and quinolones, as well as virulence genes (e.g., invA, spvC, pldA, and held). Whole-genome sequencing (WGS) was performed on 19 selected isolates. A silver nanoparticles (AgNPsol) alternative to conventional antibiotics was tested for effectiveness against multidrug-resistant (MDR) isolates. Results: From the total of 309 Salmonella isolates (65.05% from children under 4 years of age) belonging to four subtypes and four serovars, 27.86% showed resistance to at least one antibiotic, most frequently to tetracycline, ampicillin, and piperacillin. The strains frequently expressed haemolysin (67%), aesculinase (65%), and gelatinase (62%). Resistance to trimethoprim-sulfamethoxazole was encoded by the sul1 gene in 44.83% of the strains and to tetracyclines by the tet(A) gene (59.52%). The ESBL genes bla_TEM, bla_SHV, and bla_CTX-M were detected by PCR in 16.18%, 2.91%, and 0.65% of the strains, respectively. Additionally, 98.63% of the strains carried the invA marker, with notable positive associations between bla_SHV, qnrB, and sul1 with spvC. Conclusions: The present findings revealed significant patterns in Salmonella isolates, subtypes, serovars, AR, and virulence, emphasising the need for continuous surveillance of Salmonella infections. Additionally, the potential of AgNPs as an alternative treatment option was demonstrated, particularly for paediatric S. enterica infections.