Killing Bacteria by Faradaic Processes through Nano-Hydroxyapatite/MoOx Platforms.

Following the secular idea of ″restitutio ad integrum″, regeneration is the pursued option to restore bones lost after a disease; accordingly, complementing antibiotic and regeneration capacity to bone grafts represents a great scientific success. This study is a framework proposal for understanding the antimicrobial effect of biocompatible nano-hydroxyapatite/MoOx (nano-HA/MoOx) platforms on the basis of their electroactive behavior. Through cyclic voltammetry and chronoamperometry measurements, the electron transference capacity of nano-HA and nano-HA/MoOx electrodes was determined in the presence of pathogenic organisms: Pseudomonas aeruginosa and Staphylococcus aureus. Faradaic processes were confirmed and related to the switch of MoO42-/PO43- groups in the original hexagonal nano-HA crystal lattice and to the extent of OH vacancies that act as electron acceptors. Microscopic analysis of bacteria's ultrastructure showed a disruptive effect on the cytoplasmic membrane upon direct contact with the materials, which is not evident in the presence of eukaryotic cells. Experiments support the existence of a type of extracellular electron transfer (EET) process that alters the function of the bacterial cytoplasmic membrane, accelerating their death. Our findings provide strong quantitative support for a drug-independent biocidal physical approach based on EET processes between microorganisms and phosphate ceramics that can be used to combat local orthopedic infections associated with implants.

Universal Sars-Cov-2 Screening in Pregnant Women: Experience from the Italian Epidemic Outbreak.

BACKGROUND AND AIM: Sars-CoV-2 infection has rapidly spread worldwide following the first cases reported in China. Piacenza is one of the most affected cities in Italy. Many infections occurred in the hospital due to the high frequency of patients and healthcare professionals interaction. The aim of the work is to evaluate advantages of universal screening for Sars-Cov-2 in pregnant women admitted to a hospital setting and calculate frequency of infection in an obstetrical population.  Methods: all pregnant women attending Guglielmo da Saliceto Hospital in Piacenza from 22nd April to 18th June 2020 were screened for Sars-Cov-2 using a nasopharyngeal swab.  Results: 240 pregnant women were tested upon admission: all twelve (5%) testing positive were asymptomatic. None of the positive asymptomatic women developed COVID-19 symptoms or adverse perinatal outcomes. CONCLUSIONS: the diagnosis of asymptomatic pregnant women through universal screening provides the opportunity to protect mothers, babies and heath care workers. In accordance with other studies, our findings add to the growing body of evidence showing high rates of asymptomatic infection in the healthcare setting and highlight a critical need for universal screening of pregnant women.

Microbiological quality and determination of pesticide residues in the lettuce produced in Bahía Blanca's horticultural belt, Argentina.

The aims of this research were 1) to find out the possible microbiological contamination and residues of pesticides (chlorpyrifos and cypermethrin) in lettuce grown in Bahía Blanca's horticultural belt, and bacteriological quality of waters used for irrigation and post-harvest washing, 2) to investigate and compare the internalization capacity of a strain of Escherichia coli isolated from irrigation water with another hospital uropathogenic strain. Some strains of bacteria can internalize into the plant tissue. This capability presents food safety threats as they cannot be removed with standard sanitation practices. To determine bacteriological quality of lettuce, E. coli, Salmonella spp and E. coli O157: H7/NM (n = 10) were investigated. Bacteriological quality of water was determined by quantification of fecal coliforms/100 mL (n = 20). Pesticides were determined by using an improved and validated QuEChERS method combined with GC-MSD. Irrigation water in 19/20 samples did not present health risk. Bacteriological quality of lettuce met demands in 9/10 samples. Pesticides were detected in half of the samples, values exceeding the FAO recommendations. An effort is strongly recommended to implement both, best phytosanitary practices and monitoring programmes. Uropathogenic strain was able to internalize into plant tissue, while the nonpathogenic one was not.

Antibacterial alginate/nano-hydroxyapatite composites for bone tissue engineering: Assessment of their bioactivity, biocompatibility, and antibacterial activity.

Bone substitute materials based on bioceramics and polymers have evolved shifting from a passive role where they are merely accepted by the body; to an active role, where they respond to particular environmental conditions or to different types of cues generating suitable integration (osseointegration for this case) inside the host tissue. In this work, two types of composite materials based on a bioceramic (synthetic nano-hydroxyapatite, HA) and a biopolymer (sodium alginate, ALG) have been designed and assessed for promoting the bone regeneration. These materials were loaded with ciprofloxacin (CIP) for obtaining, not only a suitable material for a filling but with antibacterial properties. Therefore, their main features were studied through Fourier transformed-infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Ultraviolet-Visible (UV-Vis) spectroscopy was used for obtaining the released concentrations of CIP and Zeta-potential (ζ-potential) was used for characterizing the adsorption of CIP onto nanoparticles. The release profile of this drug has been fit with the Ritger-Peppas model, used for studying the release kinetics of hydrogel-based systems. The bioactivity of these composites was also evaluated after 30 days of incubation in a simulated body fluid solution (SBF). Then, the assessment of antibacterial capability against the three main strains cause osteomyelitis was performed. Finally, the cell viability study and the cellular morphology assay were also carried out. These last assays have shown encouraging results and, gathered with their other properties, such as their bioactivity and antibacterial properties; they could lead to propose these materials as new bone filler antibiotic devices.

Self-fluorescent antibiotic MoOx-hydroxyapatite: a nano-theranostic platform for bone infection therapies.

Nowadays, the repair of large-size bone defects represents a huge medical challenge. A line of attack is the construction of advanced biomaterials having multifunctional properties. In this work, we show the creation of biocompatible MoOx-hydroxyapatite nanoparticles (nano-HA/MoOx) that simultaneously exhibit self-activated fluorescence and antibiotic skills. Along this text, we demonstrate that the insertion of molybdenum, an essential trace element, into the non-stoichiometric calcium deficient hydroxyapatite lattice generates intrinsic electronic point defects that exacerbate its epifluorescence blue emission and provokes new red emissions, preserving, always, its bioactivity. Furthermore, these point defects, acting as electron acceptors, stimulate the materials' biological redox status and promote the death of pathogen microorganisms after their direct contact. A putative mechanism, by which bacteria lose electrons from their metabolic circuit that alter the function of their cytoplasmic membrane and potentially die, agrees with our results. Our findings highlight the importance of tuning the electronic communications between biomaterial interfaces and biological units, and support the use of self-fluorescent MoOx-hydroxyapatite nanoparticles as fundamental building blocks for new real-time imaging platforms against bone infection.

Prevalence and species diversity of nontuberculous mycobacteria in drinking water supply system of Bahía Blanca City, Argentina.

Background: There is evidence that tap water is the vehicle through which nontuberculous mycobacteria (NTM) infect or colonize the human body. The objective of this study was to determine the presence and diversity of NTM in the water distribution system of Bahía Blanca city, Argentina (sites S2/S3) and in the dike that supplies water to it (S1). Methods: Culture-dependent method, biochemical tests, and molecular method (16S rRNA sequencing gene) were combined to detect and identify NTM. Results: NTM were isolated in 51.6% (64/124) of all the samples analyzed. Mycobacterium gordonae was the most frequently isolated organism (15/64) in all samples analyzed, followed by Mycobacterium peregrinum and Mycobacterium frederiksbergense. Significant differences were found in the residual chlorine values between sampling S2 and S3. In both sites, maximum counts were recorded but they did not correlate with low chlorine values. A concentration higher than 500 colony-forming unit/L of NTM was never found, which can be attributed to the negative effect caused by decontamination methods being a point to consider for the recovery of NTM. In 46.9% (30/64) of samples, both methods coincided in the identification, and the obtained sequences presented ≥99% identity. Identification at the species level was achieved in 50% (32/64) of the isolates. Nearly 17.2% (11/64) of the isolates showed a similarity <99%. Conclusions: It should be taken into account that sequencing of the 16S rRNA gene and biochemical tests are useful for the identification of several species, but it is necessary to incorporate other genes (hsp 65 and rpo B) to obtain accurate identification.

Multi-drug delivery system based on lipid membrane mimetic coated nano-hydroxyapatite formulations.

Local delivery systems from an osteoconductive biomaterial are suggested as a promising strategy to avoid simultaneously peri-implant traumas and to induce tissue regeneration. In this work, it is detailed the design and construction of a multi-drug delivery formulation based on lipid membrane mimetic coated nano-hydroxyapatite, LMm/nano-HA, as a bone-specific drug delivery approach. The optimal LMm/nano-HA formulation was selected after analysing the lipid/nano-HA interaction by dynamic light scattering (DLS), ζ-potential, transmission electron microscopy (TEM), polarized optical microscopy (POM), differential scanning calorimetry (DSC) and UV-vis spectroscopy. After the initial screening, Ciprofloxacin and Ibuprofen simultaneous -load and -release efficiency from selected LMm/nano-HA was assessed. pH-responsive kinetic profiles of local drug distribution were characterized and compared with currently applied systemic doses. Finally, the systems' biocompatibility and drug released activity were positively validated. The obtained results demonstrated that LMm/nano-HA formulations can represent a valuable multi-modal platform in bone tissue therapies.

Effect of chlorine on Mycobacterium gordonae and Mycobacterium chubuense in planktonic and Biofilm State.

Background: : There is evidence that drinking water could be a source of infections with pathogenic nontuberculous mycobacteria (NTM) potentially risky to human health. The aim was to investigate the resistance of two NTM isolated from drinking water, Mycobacterium gordonae and Mycobacterium chubuense, at different concentrations of chlorine (as sodium hypochlorite), used in drinking water sanitation. Methods: : The NTM were grown in suspension and in biofilms and were challenged with biocide for 10 and 60 min. Results: To obtain 7-log reduction from the initial population of M. chubuense, in the planktonic state, there were necessary 20 ppm of chorine and 60 min of exposure. The same effect was achieved in M. gordonae with 10 ppm for the same period. The maximum reduction of both NTM in biofilm was 3-log reduction and was achieved using 30 ppm for 60 min. The chlorine susceptibility of cells in biofilms was significantly lower than that of planktonic cells. The results highlight the resistance of both NTM to the concentrations used in routine water sanitation (0.2 ppm according to Argentine Food Code). Differences in chlorine resistance found between the two NTM in planktonic growth decrease when they are grown in biofilm. Conclusion: This suggests that current water disinfection procedures do not always achieve effective control of NTM in the public supply system, with the consequent health risk to susceptible population, and the need to take into account biofilms, because of their deep consequences in the way to analyze the survival of prokaryotic cells in different environments.

Electroactive Mg2+-Hydroxyapatite Nanostructured Networks against Drug-Resistant Bone Infection Strains.

Surface colonization competition between bacteria and host cells is one of the critical factors involved in tissue/implant integration. Current biomaterials are evaluated for their ability both of withstanding favorable responses of host tissue cells and of resisting bacterial contamination. In this work, the antibacterial ability of biocompatible Mg2+-substituted nanostructured hydroxyapatite (HA) was investigated. The densities of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli strains were significantly decreased after culture in the presence of Mg-substituted HA materials in direct correlation with Mg2+-Ca2+ switch in the HA lattice. It was noticed that this decrease was accompanied by a minimal alteration of bacterial environments; therefore, the Mg2+-HA antibacterial effect was associated with the material surface topography and it electroactive behavior. It was observed that 2.23 wt % Mg2+-HA samples exhibited the best antibacterial performance; it decreased 2-fold the initial population of E. coli, P. aeruginosa, and S. aureus at the intermediate concentration (50 mg mL-1 of broth). Our results reinforce the potential of Mg-HA nanostructured materials to be used in antibacterial coatings for implantable devices and/or medicinal materials to prevent bone infection and to promote wound healing.

Biogeochemical and hydrological drivers of the dynamics of Vibrio species in two Patagonian estuaries.

The ecology of the most relevant Vibrio species for human health and their relation to water quality and biogeochemistry were studied in two estuaries in Argentinian Patagonia. Vibrio cholerae and Vibrio parahaemolyticus were reported in >29% of cases at the Río Colorado and Río Negro estuaries. Neither the pandemic serogroups of Vibrio cholerae O1, Vibrio cholerae O139 nor the cholera toxin gene were detected in this study. However, several strains of V. cholerae (not O1 or O139) are able to cause human disease or acquire pathogenic genes by horizontal transfer. Vibrio vulnificus was detected only in three instances in the microplankton fraction of the Río Negro estuary. The higher salinity in the Río Colorado estuary and in marine stations at both estuaries favours an abundance of culturable Vibrio. The extreme peaks for ammonium, heterotrophic bacteria and faecal coliforms in the Río Negro estuary supported a marked impact on sewage discharge. Generally, the more pathogenic strains of Vibrio have a faecal origin. Salinity, pH, ammonium, chlorophyll a, silicate and carbon/nitrogen ratio of suspended organic particulates were the primary factors explaining the distribution of culturable bacteria after distance-based linear models. Several effects of dissolved organic carbon on bacterial distribution are inferred. Global change is expected to increase the trophic state and the salinisation of Patagonian estuaries. Consequently, the distribution and abundance of Vibrio species is projected to increase under future changing baselines. Adaptation strategies should contribute to sustaining good water quality to buffer climate- and anthropogenic- driven impacts.

Microbial enumeration of different functional groups and bacterial behavior in acid basic conditions of a biotoxic landfill leachate of Bahía Blanca, Argentina.

Leachate is liquid waste from refuse biological decomposition or rainwater percolation in a landfill. This research focused on leachate produced by a landfill in Bahia Blanca, Buenos Aires, Argentina. The research studied the main microbial populations involved in wastewater treatment, analyzed the behavior of bacteria isolated from leachate at different pH values, and appraised leachate biotoxicity. The number of bacteria varied by type, ranging from 1 x 10(4) to 1 x 10(5) CUF/mL aerobic heterotrophic bacteria (AHB); 1 x 10(3) to 1 x 10(5) CUF/mL anaerobic heterotrophic bacteria (ANHB); 1 x 10(5) to 1 x 10(6) CUF/mL sulfite-reducing bacteria (SRB); 1 x 10(3) to 1 x 10(6) NMP/mL nitrate-reducing bacteria (NRB); and 1 x 10(2) to 1 x 10(4) NMP/mL ammonium-oxidizing bacteria (AOB). Several microbial strains developed at pH 5, 7, and 10. These pH values changed to 9 in the culture media after a 48-hour incubation. Leachate was used to water lettuce seeds (Lactuca sativa capitata). Its toxicity was proved by full inhibition of plant development.

Effects of raloxifene and continuous combined hormone therapy on haemostasis variables: a multicenter, randomized, double-blind study.

INTRODUCTION: Hormone replacement therapy is known to increase the risk of thromboembolic events. We compared the effects of HRT and raloxifene on some haemostasis variables. MATERIALS AND METHODS: In a multicenter, double-blind study, 54 healthy postmenopausal women were randomized to receive either continuous treatment with 2 mg 17beta-estradiol plus 1 mg norethisterone acetate (n=30) or 60 mg raloxifene (n=24) daily for 12 months. Blood samples were collected at baseline and at 3, 6 and 12 months to evaluate therapy effects on some haemostasis variables (factor VII, factor VIII, prothrombin fragments 1 and 2, protein C, protein C activity, protein S, thrombin-antithrombin complex, D-dimer, antithrombin, fibrinogen and plasminogen activator inhibitor). RESULTS: Both raloxifene and continuous combined hormone therapy modified the haemostasis variables toward a more prothrombotic profile. Factor VIII (p<0.01) and fibrinogen (p<0.05) plasma levels significantly increased at 6 months, prothrombin fragments 1 and 2 (p<0.05) significantly increased at 12 months, whereas protein C activity (p<0.001) and antithrombin (p<0.01) significantly decreased at 12 months in both groups. CONCLUSIONS: Our results demonstrate that raloxifene and continuous combined hormone therapy exhibit the same prothrombotic profile. Both treatments induced an increase in procoagulant parameters at 6 months and a decrease in anticoagulant parameters at 12 months.

Zinc complexes with cyclic derivatives of alpha-ketoglutaric acid thiosemicarbazone: Synthesis, X-ray structures and DNA interactions.

Six new cyclic ligands derived from alpha-ketoglutaric acid thiosemicarbazone (H(3)ct) and their zinc complexes have been synthesized and characterized by analytical and spectroscopic (IR and NMR) studies. The X-ray structures of ligands Me-H(2)ct(C) (1), Allyl-H(2)ct(c) (3) and of complex [Zn(Me-Hct(C))(2)(OH(2))(2)].2H(2)O (7) have been determined. In complex (7) the zinc atom lies on a twofold axis and is surrounded in a tetrahedral coordination by two water molecules and two carboxylic oxygen donor atoms from the ligand. DNA titration in the UV-visible region and thermal denaturation have been employed to determine the details of DNA binding for the studied compounds. Studies of nuclease activity have also been performed with all our compounds through a gel electrophoresis experiment using plasmid pBR322 showing that no DNA breakings take place. Tests in vitro on human leukemia cell line U937 have been carried out on cell growth inhibition where solubility of the compounds allowed the experiments.

Effects of Bacillus subtilis O9 biosurfactant on the bioremediation of crude oil-polluted soils.

The application of a surfactant from Bacillus subtilis O9 (Bs) on the bioremediation of soils polluted with crude oil was assayed in soil microcosms under laboratory conditions. Three concentrations of biosurfactant were assayed (1.9, 19.5, and 39 mg kg(-1) soil). Microcosms without biosurfactant were prepared as controls. During the experiment, the crude oil-degrading bacterial population, the aliphatic and aromatic hydrocarbons were monitored in each microcosm. The results indicated that applying Bs did not negatively affect the hydrocarbon-degrading microbial population Concentrations of 19 and 19.5mg (Bs) per kilogram of soil stimulated the growth of the population involved in the crude oil degradation, and accelerated the biodegradation of the aliphatic hydrocarbons. However, none of the assayed Bs concentrations stimulated aromatic hydrocarbon degradation.

Copper(II) complexes with substituted thiosemicarbazones of alpha-ketoglutaric acid: synthesis, X-ray structures, DNA binding studies, and nuclease and biological activity.

New alpha-ketoglutaric acid thiosemicarbazone (H(3)ct) derivatives and their copper complexes were synthesized and characterized by analytical and spectroscopic (IR and NMR) methods. For two of the ligands, Me-H(3)ct and Allyl-H(3)ct, and for a complex, [Cu(Me-Hct)(OH(2))](n) x 2nH(2)O, the X-ray structures were also determined. In the latter the copper atom shows a 4 + 1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the SNO tridentate ligand and the fourth by a carboxylic oxygen of an adjacent molecule that gives rise to a polymeric chain. DNA binding constants were determined, and studies of thermal denaturation profiles and nuclease activity were also performed. Tests in vitro on human leukemia cell line U937 were carried out on cell growth inhibition, cell cycle, and apoptosis induction.

A one-year follow-up on the effects of raloxifene on thyroid function in postmenopausal women.

OBJECTIVE: Estrogens increase serum thyroxine-binding globulin (TBG) and total thyroxine (TT4) concentrations. Serum free thyroxine (FT4) concentrations, however, remain normal. Raloxifene (RAL) is a selective estrogen receptor modulator used to treat postmenopausal osteoporosis. Data on the long-term effects of RAL on thyroid physiology are scanty. We evaluated the effects of RAL administration for 1 year on thyroid function in osteopenic, postmenopausal women. DESIGN: Fifty osteopenic, postmenopausal women were randomly assigned to receive either RAL (60 mg/day, n = 25) or placebo (PL, n = 25) for 1 year, in a double-blind study. Measurements of serum TBG, TT4, FT4, thyroid-stimulating hormone (TSH), thyroid hormone-binding ratio (THBR), FT4 index (FT4-I) and TT4/TBG ratio were carried out at baseline and after 4 and 12 months of therapy. RESULTS: Baseline values were similar in both treatment groups. Serum TBG concentrations were increased during RAL treatment from baseline values of 29.60 +/- 0.9 microg/mL to 31.45 +/- 1.33 and 32.34 +/- 1.37 microg/mL at 4 months and 1 year, respectively (P < 0.05, baseline v 1-year values) but were unchanged during PL treatment. A small, insignificant increase in TT4 and TSH concentrations occurred in the RAL group and no changes in the PL group. All other values were unchanged during either treatment. CONCLUSIONS: These results demonstrate that RAL significantly increased serum TBG levels, but the changes were small and not accompanied by changes in FT4-I, FT4, or TSH concentrations, suggesting that long-term RAL treatment is unlikely to clinically affect the thyroid status in euthyroid, postmenopausal women.

Effects of raloxifene on carotid blood flow resistance and endothelium-dependent vasodilation in postmenopausal women.

Raloxifene is one of the most important selective estrogen receptor modulators currently employed for the treatment of postmenopausal osteoporosis. However, it has also been suggested that this compound affects the vascular system. We evaluated both carotid blood flow resistance and endothelium-dependent vasodilation in 50 healthy postmenopausal women randomly assigned to receive, in a double blind design, either raloxifene (60 mg per day; N=25 subjects) or placebo (N=25 subjects) for 4 months. Indices of carotid blood flow resistance, such as the pulsatility index (PI) and resistance index (RI), as well as the flow-mediated brachial artery dilation were measured both at baseline and at the end of treatment. Changes in PI were -1.86+/-2.24 and -2.15+/-2.22% after placebo and raloxifene treatment, respectively, with no significant differences between groups. Changes in RI were -0.77+/-1.72 and -1.81+/-1.54% after placebo and raloxifene treatment, respectively, with no significant differences between groups. At the end of the treatment period, the increments in artery diameter measured after the flow stimulus were 10.79+/-2.39 and 6.70+/-1.23% for placebo and raloxifene, respectively, with no significant differences between groups. These results demonstrate no significant effects of raloxifene on either carotid blood flow resistance or brachial artery flow-mediated dilation in postmenopausal women.

Cu(II) complexes with heterocyclic substituted thiosemicarbazones: the case of 5-formyluracil. Synthesis, characterization, x-ray structures, DNA interaction studies, and biological activity.

Two new 5-formyluracil thiosemicarbazone (H(3)ut) derivatives, Me-H(3)ut (1) and Me(2)-H(3)ut (2), were synthesized by reacting thiosemicarbazides, mono- and dimethylated on the aminic nitrogen, with 5-formyluracil and were subsequently characterized. These ligands, treated with copper chloride and nitrate, afforded three complexes: [Cu(Me-H(3)ut)Cl(2)].H(2)O (3), [Cu(Me(2)-H(3)ut)Cl(2)].H(2)O (4), and [Cu(Me-H(3)ut)(NO(3))(OH(2))(2)]NO(3) (5). The crystal structures of these complexes have been determined by single-crystal X-ray diffraction. In 3 and 4, a similar pentacoordination is present; the copper atom is surrounded by the ligand SNO donor atoms and by two chloride ions. The structure of 5 consists of [Cu(Me-H(3)ut)(NO(3))(OH(2))(2)](+) cations and nitrate anions. The copper coordination (4 + 2) involves the SNO ligand atoms and a water oxygen in the basal plane; the apical positions are occupied by a second water oxygen and by an oxygen of a monodentate nitrate group. Two biochemical techniques, namely DNA titration in the UV-vis region and thermal denaturation, have been employed to probe the details of DNA binding of these compounds. Analysis of the results suggests that our compounds are able to interact with DNA by electrostatic and groove binding but not by intercalation. The compounds have been also tested in vitro on human leukemic cell line U937, but they are not able to inhibit significantly cell proliferation.