Electrospun Nanofibrous Mesh Based on PVA, Chitosan, and Usnic Acid for Applications in Wound Healing

Injuries and diseases of the skin require accurate treatment using nontoxic and noninvasive biomaterials, which aim to mimic the natural structures of the body. There is a strong need to develop biodevices capable of accommodating nutrients and bioactive molecules and generating the process of vascularization. Electrospinning is a robust technique, as it can form fibrous structures for tissue engineering and wound dressings. The best way of forming such meshes for wound healing is to choose two polymers that complement each other regarding their properties. On the one hand, PVA is a water-soluble synthetic polymer widely used for the preparation of hydrogels in the field of biomedicine owing to its biocompatibility, water solubility, nontoxicity, and considerable mechanical properties. PVA is easy to subject to electrospinning and can offer strong mechanical stability of the mesh, but it is necessary to improve its biological properties. On the other hand, CS has good biological properties, including biodegradability, nontoxicity, biocompatibility, and antimicrobial properties. Still, it is harder to electrospin and does not possess as good mechanical properties as PVA. As these structures also allow the incorporation of bioactive agents due to their high surface-area-to-volume ratio, the interesting point was to incorporate usnic acid into the structure as it is a natural and suitable alternative agent for burn wounds treatment which avoids an improper or overuse of antibiotics and other invasive biomolecules. Thus, we report the fabrication of an electrospun nanofibrous mesh based on PVA, chitosan, and usnic acid with applications in wound healing. The obtained nanofibers mesh was physicochemically characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). In vitro biological assays were performed to evaluate the antimicrobial properties of the samples using the MIC (minimum inhibitory concentration) assay and evaluating the influence of fabricated meshes on the Staphylococcus aureus biofilm development, as well as their biocompatibility (demonstrated by fluorescence microscopy results, an XTT assay, and a glutathione (GSH) assay).

Antimicrobial Efficiency of Some Essential Oils in Antibiotic-Resistant Pseudomonas aeruginosa Isolates

Pseudomonas aeruginosa is a non-fermentative Gram-negative opportunistic pathogen, frequently encountered in difficult-to-treat hospital-acquired infections and also wastewaters. The natural resistance of this pathogen, together with the frequent occurrence of multidrug-resistant strains, make current antibiotic therapy inefficient in treating P. aeruginosa infections. Antibiotic therapy creates a huge pressure to select resistant strains in clinical settings but also in the environment, since high amounts of antibiotics are released in waters and soil. Essential oils (EOs) and plant-derived compounds are efficient, ecologic, and sustainable alternatives in the management of various diseases, including infections. In this study, we evaluated the antibacterial effects of four commercial essential oils, namely, tea tree, thyme, sage, and eucalyptus, on 36 P. aeruginosa strains isolated from hospital infections and wastewaters. Bacterial strains were characterized in terms of virulence and antimicrobial resistance. The results show that most strains expressed soluble pore toxin virulence factors such as lecithinase (89–100%) and lipase (72–86%). All P. aeruginosa strains were positive for alginate encoding gene and 94.44% for protease IV; most of the strains were exotoxin producers (i.e., 80.56% for the ExoS gene, 77.78% for the ExoT gene, while the ExoU gene was present in 38.98% of the strains). Phospholipase-encoding genes (plc) were identified in 91.67/86.11% of the cases (plcH/plcN genes). A high antibiotic resistance level was identified, most of the strains being resistant to cabapenems and cephalosporins. Cabapenem resistance was higher in hospital and hospital wastewater strains (55.56–100%) as compared to those in urban wastewater. The most frequently encountered encoding genes were for extended spectrum β-lactamases (ESBLs), namely, bla_CTX-M (83.33% of the strains), bla_SHV (80.56%), bla_GES (52.78%), and bla_VEB (13.89%), followed by carbapenemase-encoding genes (bla_VIM, 8.33%). Statistical comparison of the EOs’ antimicrobial results showed that thyme gave the lowest minimum inhibitory concentrations (MIC) and minimum biofilm eradication concentrations (MBEC) in P. aeruginosa-resistant isolates, making this EO a competitive candidate for the development of efficient and ecologic antimicrobial alternatives.

Atmospheric Pressure Plasma Activation of Hydroxyapatite to Improve Fluoride Incorporation and Modulate Bacterial Biofilm

Despite the technological progress of the last decade, dental caries is still the most frequent oral health threat in children and adults alike. Such a condition has multiple triggers and is caused mainly by enamel degradation under the acidic attack of microbial cells, which compose the biofilm of the dental plaque. The biofilm of the dental plaque is a multispecific microbial consortium that periodically develops on mammalian teeth. It can be partially removed through mechanical forces by individual brushing or in specialized oral care facilities. Inhibition of microbial attachment and biofilm formation, as well as methods to strengthen dental enamel to microbial attack, represent the key factors in caries prevention. The purpose of this study was to elaborate a cold plasma-based method in order to modulate microbial attachment and biofilm formation and to improve the retention of fluoride (F-) in an enamel-like hydroxyapatite (HAP) model sample. Our results showed improved F retention in the HAP model, which correlated with an increased antimicrobial and antibiofilm effect. The obtained cold plasma with a dual effect exhibited through biofilm modulation and enamel strengthening through fluoridation is intended for dental application, such as preventing and treating dental caries and enamel deterioration.

Antibiotic resistance profiles in cultivable microbiota isolated from some romanian natural fishery lakes included in Natura 2000 network

BACKGROUND

The present study aims the characterization of antibiotic resistance phenotypes and encoding genes in bacterial strains isolated from some Romanian aquatic fishery lowland salted lakes.

MATERIAL/METHODS

This study was conducted on 44 bacterial strains, mainly belonging to species used as microbiological indicators of fecal pollution isolated from four natural fishery lakes. All strains were tested for their antibiotic susceptibility by disk diffusion method. Simplex and multiplex PCR were performed to identify the β-lactams antibiotic resistance genes (blaNMD, blaOXA-48, blaVIM, blaIMP, blaCTX-M, blaTEM), sulfonamides (Sul1, Sul2), tetracyclines (TetA, TetB, TetC, TetD, TetM), aminoglycosides (aac3Ia), vancomycin (VanA, VanB, VanC), macrolides (ermA, ermB, ermC) as well as the plasmid-mediated quinolone resistance (PMQR) markers (QnrA, QnrB, QnrS), and class 1 integrons (Int1, drfA1-aadA1).

RESULTS

The Enterococcus spp. isolates exhibited phenotypic resistance to vancomycin (35 %) and macrolides (erythromycin) (75 %); from the vancomycin - resistant strains, 5 % harboured VanA (E. faecalis), while the erythromycin resistant isolates were positive for the ermA gene (E. faecalis - 10 %, E. faecium - 5 %). The Gram- negative rods (GNR) exhibited a high level of resistance to β-lactams: cefuroxime (63 %), cefazolin (42 %), ceftriaxone (8 %), ceftazidime and aztreonam (4 % each). The genetic determinants for beta-lactam resistance were represented by blaCTX-M-like (33 %), blaNDM-like and blaIMP-like (8.33 %) genes. The resistance to non-β-lactam antibiotics was ascertained to the following genes: quinolones (QnrS - 4.16 %); sulfonamides (Sul1-75 %, Sul2-4.16 %); aminoglycosides (aac3Ia - 4.16 %); tetracyclines (tetA - 25 %, tetC - 15 %). The integrase gene was found in more than 50 % of the studied strains (58.33 %).

CONCLUSIONS

The cultivable aquatic microbiota from fishery lakes is dominated by enterococci and Enterobacterales strains. The GNR strains exhibited high levels of β-lactam resistance mediated by extended spectrum beta-lactamases and metallo-β-lactamases. The Enterococcus sp. isolates were highly resistant to macrolides and vancomycin. The high level and diversity of resistance markers, correlated with a high frequency of integrons is suggesting that this environment could act as an important reservoir of antibiotic resistance genes with a great probability to be horizontally transmitted to other associated species from the aquatic sediments microbiota, raising the potential zoonotic risk for fish consumers.

Tertiary Treatment of Livestock Wastewater in the Context of Alternative Water Resources for Sustainable Agriculture

The limited availability and quality of water resources are key issues of water management, and the protection and preservation of water resources are a requirement in the context of accelerated economic growth and principles of sustainable development. The experimental research presented in this paper is based on the need to identify alternative water sources and support unconventional wastewater treatment methods which would enable their reuse in areas affected by water scarcity and drought. Livestock wastewater contain significant levels of nutrients (nitrogen and phosphorus) and may represent an attractive water source for crop irrigation. This paper evaluates the efficacy of a proposed technological process for tertiary wastewater treatment consisting of two steps: electrochemical treatment for the removal of suspended and colloidal impurities and ozone disinfection. The experimental results showed higher efficiencies for the removal of chemical pollutants (92.5% COD, 79.3% BOD, 98.6% TSS, 41% residue saline) and significant inactivation of microorganisms (over 99.9% for total coliform bacteria and in some cases 100% for faecal coliform bacteria and faecal streptococci). The quality of the effluent complies with the regulations for wastewater use in agriculture and allows its reuse for different categories of use considering the required conditions for soil/crops. The successful application of treated wastewater to agricultural crops depends in a high extent on the good practices aimed on the improvement of crop yield and quality, optimisation of soil productivity and protection of the environment undertaken by the economic entities.

Antibiotic Resistance Profile and Chemical Quality Assessment of Groundwater Sources from Periurban Area of Bucharest, Romania

Twenty-two groundwater sources mainly used for drinking purpose in Bucharest peri-urban area were investigated for assessment of physico-chemical and microbiological quality with a view to determining its potential risk to public health. Results of chemical analysis revealed that nitrites, sulphates and chlorides were below the permissible levels, while 63.64% of the analysed groundwater sources exceeded the maximum admissible concentration for nitrates, with concentration variations ranging from 67.27 to 523.19 mg/L. The bacteriological analysis showed that in about 63% of groundwater sources total coliform, faecal coliform and enterococci have exceeded the threshold limits recommended by the Drinking Water Directive 98/83/EC and the Romanian Law. Another aim of the study was to investigate the prevalence of antibiotic resistance among Gram-negative strains isolated from groundwater sources. There observed the resistance to many antibiotics, particularly: ticarcillin (80%), aztreonam (29%), gentamicin (11%), imipenem (9%), ceftriaxone (9%), ceftazidime (3%) and ciprofloxacin (3%). Significant higher resistance rates were observed in strains isolated from shallow groundwater sources as compared with strains isolated from deep groundwater sources. Pseudomonas sp. (26%) isolates with multiple-drug resistance (MDR) were encountered. The results of the study revealed a bacteriological contamination and high levels of nitrate concentrations in most of the groundwater samples, which could pose an important risk to human health.

Technological Solution for the Treatment of Wastewater Resulting from Autochthonous Aquacultures in Order to Protect the Marine Water Quality

This paper depicts the research conducted at a micro-pilot scale on autochthonous cultures in order to develop adequate technological solutions for the treatment of wastewater resulting from shrimp cultures (Palaemonidae) that would ensure the protection of the Black Sea ecosystem and constitute an applicable tool for the development of aquaculture in Romania. The proposed objectives were attained by adopting an integrated system of marine cultures shrimps-mussels-macrophyte algae, followed by a conventional chemical treatment step using aluminium sulphate recovered from metallurgical slags. This system together with wastewater treatment ensures an optimum development of species and a minimum load of pollutants in the aquatic environment.

Beta-lactam and quinolone resistance markers in uropathogenic strains isolated from renal transplant recipients

Our objectives were to investigate the extended-spectrum beta-lactamases (ESBLs) and carbapenemases (CR) genetic determinants and to assess the association between ESBL production and quinolone resistance in bacterial strains isolated from renal transplant recipients with urinary tract infections. Material and methods: A number of 30 isolates were recovered from urine specimens of patients with renal transplant from October 2015 to March 2016. The isolates were analyzed for ESBL production using double disc synergy test and for CR production by the Hodge test. Phenotypically confirmed isolates were screened by PCR for the identification of ESBL, CR and fluoroquinolone resistance genes. Results: The 30 clinical bacterial strains isolated from urinary tract infections in renal transplant recipients were identified as Klebsiella pneumoniae (17), Pseudomonas aeruginosa (7), Morganella morganii (2), Escherichia coli (2), Edwardsiella tarda (1) and Enterobacter cloacae (1). Out of them, 22 isolates were ESBL producers and 20 multi-drug resistant (MDR) (i.e., 13 K. pneumoniae and 7 P. aeruginosa strains). More than half of the ESBL clinical strains (14/22, 63.63%) revealed at least one ESBL gene, the most frequent being blaCTX-M type (18/22, 81.81%), either alone (4/22, 18.18%) or in combination with another ESBL gene (17/22, 77.27%), followed by blaTEM (13/22, 59.09%). The blaOXA-48 was present in 10 isolates (33.33%). The most frequent association of ESBLs and CR genes (5/14, 35.71%) was revealed by blaCTX-M- blaTEM - blaOXA-48, encountered particularly among K. pneumoniae isolates (4/17, 23.52%). The qnrB gene was identified in five strains, i.e. one P. aeruginosa ESBL isolate (expressing the blaCTX-M gene) and four K. pneumoniae ESBL isolates (harboring the blaCTX-M - blaTEM genes combination). Conclusions: The uropathogenic strains isolated from renal transplant recipients exhibited high rates of MDR and beta-lactam resistance. The selective pressure exerted by quinolones could enable uropathogenic bacteria to acquire resistance to this class of antibiotics.

Neuroprotective and consequent neurorehabilitative clinical outcomes, in patients treated with the pleiotropic drug cerebrolysin

BACKGROUND

Discovery of neurotrophic factors--emblematic: the nerve growth factor (NGF)--resulted in better approaching central nervous system (CNS) lesions. Recently, another crucial property has been unveiled: their rather unique pleiotropic effect. Cerebrolysin is a peptide mixture that penetrates the blood-brain barrier in significant amounts and mimics the effects of NGF.

METHODS

Comparative analysis: Cerebrolysin treated (10 ml x 2/day, i.v. x 3 weeks) vs. non-treated, in patients (all received aside, a rather equivalent complementary, pharmacological and physical, therapy). Two lots of patients, admitted in our Physical & Rehabilitation (neural-muscular) Medical-PR(n-m)M-Clinic Division, during 2007-2009: 69 treated with Cerebrolysin (22 F, 47 M; Average: 59.333; Mean of age: 61.0 Years old; Standard deviation 16.583) and 70 controls (41 F, 29 M; A: 70.014; M.o.a.: 70.5 Y.o.; S.d.: 6.270) were studied. The total number of assessed items was 13: most contributive in relation with the score of Functional Independence Measure at discharge (d FIM), were: admission (a FIM), number of physical therapy days (PT), number of hospitalization days (H), age (A) and--relatively--days until the first knee functional extension (KE). Concomitantly, the main/key, focused on neuro-motor rehabilitative outcomes, functional/analytical parameters, have been assessed regarding the speed in achieving their functional recovery.

RESULTS

Concerning d FIM, there have not been objectified significant differences between the two lots (p=0.2453) but regarding key, focused on neuro-motor rehabilitative outcomes, functional/analytical parameters: KE (p=0.0007) and days until the first time recovery of the ability to walk between parallel bars (WPB--p=0.0000)--highly significant differences in favor of Cerebrolysin lot resulted.

CONCLUSION

Cerebrolysin administration, as neurorehabilitative outcomes, proved to hasten, statistically significant, especially the recovery of some critical, for standing and walking, parameters. Thus encouraged, we have now initiated a comprehensive national, 5 year retrospective, multi-centre--based on unitary data acquisition frame and mathematical apparatus--study, to evaluate the results of the treatment with Cerebrolysin in traumatic brain injuries (TBI).