BSAC standardized disc susceptibility testing method (version 4)

Newly synthesized palladium(II) complexes with dialkyl esters of (S,S)-propylenediamine-N,N'-di-(2,2'-di-(4-hydroxy-benzil))acetic acid: in vitro investigation of biological activities and HSA/DNA binding

The four new ligands, dialkyl esters of (S,S)-propylenediamine-N,N'-di-(2,2'-di-(4-hydroxy-benzil))acetic acid (R2-S,S-pddtyr·2HCl) (R = ethyl (L1), propyl (L2), butyl (L3), and pentyl (L4)) and corresponding palladium(II) complexes have been synthesized and characterized by microanalysis, infrared, 1H NMR and 13C NMR spectroscopy. In vitro cytotoxicity was evaluated using the MTT assay on four tumor cell lines, including mouse mammary (4T1) and colon (CT26), and human mammary (MDA-MD-468) and colon (HCT116), as well as non-tumor mouse mesenchymal stem cells. Using fluorescence spectroscopy were investigated the interactions of new palladium(II) complexes [PdCl2(R2-S,S-pddtyr)]; (R = ethyl (C1), propyl (C2), butyl (C3), and pentyl (C4)) with calf thymus human serum albumin (HSA) and DNA (CT-DNA). The high values of the binding constants, Kb, and the Stern-Volmer quenching constant, KSV, show the good binding of all complexes for HSA and CT-DNA. The mentioned ligands and complexes were also tested on in vitro antimicrobial activity against 11 microorganisms. Testing was performed by the microdilution method, where the minimum inhibitory concentration (MMC) and the minimum microbicidal concentration (MMC) were determined.

Novel lactoferrin-conjugated gallium complex to treat Pseudomonas aeruginosa wound infection

Pseudomonas aeruginosa is one of the leading causes of opportunistic infections such as chronic wound infection that could lead to multiple organ failure and death. Gallium (Ga3+) ions are known to inhibit P. aeruginosa growth and biofilm formation but require carrier for localized controlled delivery. Lactoferrin (LTf), a two-lobed protein, can deliver Ga3+ at sites of infection. This study aimed to develop a Ga-LTf complex for the treatment of wound infection. The characterisation of the Ga-LTf complex was conducted using differential scanning calorimetry (DSC), Infra-Red (FTIR) and Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES). The antibacterial activity was assessed by agar disc diffusion, liquid broth and biofilm inhibition assays using the colony forming units (CFUs). The healing capacity and biocompatibility were evaluated using a P.aeruginosa infected wound in a rat model. DSC analyses showed thermal transition consistent with apo-lactoferrin; FTIR confirmed the complexation of gallium to lactoferrin. ICP-OES confirmed the controlled local delivery of Ga3+. Ga-LTf showed a 0.57 log10 CFUs reduction at 24 h compared with untreated control in planktonic liquid broth assay. Ga-LTf showed the highest antibiofilm activity with a 2.24 log10 CFUs reduction at 24 h. Furthermore, Ga-LTf complex is biocompatible without any adverse effect on brain, kidney, liver and spleen of rats tested in this study. Ga-LTf can be potentially promising novel therapeutic agent to treat pathogenic bacterial infections.

Biosynthesis and characterization of silver nanoparticles synthesized using extracts of Agrimonia eupatoria L. and in vitro and in vivo studies of potential medicinal applications

This research explores the synthesis, characterization, and biological activities of silver nanoparticles (AgNPs) derived from acetone (AgNPs-acetone) and aqueous (AgNPs-H2O) extracts of Agrimonia eupatoria. The nanoparticles exhibit isometric morphology and uniform size distribution, as elucidated through Transmission Electron Microscopy (TEM) and high-resolution TEM (HRTEM) analyses. The utilization of Scanning Transmission Microscopy (STEM) with High-Angle Annular Dark-Field (HAADF) imaging and energy dispersive spectrometry (EDS) confirms the crystalline nature of AgNPs. Fourier Transform Infrared (FTIR) analysis reveals identical functional groups in the plant extracts and their corresponding AgNPs, suggesting the involvement of phytochemicals in the reduction of silver ions. Spectrophotometric monitoring of the synthesis process, influenced by various parameters, provides insights into the kinetics and optimal conditions for AgNP formation. The antioxidant activities of the plant extracts and synthesized AgNPs are evaluated through DPPH and ABTS methods, highlighting AgNPs-acetone as a potent antioxidant. Third-instar larvae exposed to the extracts have differential effects on DNA damage, with the acetone extract demonstrating antigenotoxic properties. Similarly, biosynthesized AgNPs-acetone displays antigenotoxic effects against EMS-induced DNA damage. The genotoxic effect of water extract and AgNPs-acetone was dose-dependent. Hemolytic potential is assessed on rat erythrocytes, revealing that low concentrations of AgNPs-acetone and AgNPs-H2O had a nontoxic effect on erythrocytes. Cytotoxicity assays demonstrate time-dependent and dose-dependent effects, with AgNPs-acetone exhibiting superior cytotoxicity. Proapoptotic activity is confirmed through apoptosis induction, emphasizing the potential therapeutic applications of AgNPs. The antimicrobial activity of AgNPs reveals concentration-dependent effects. AgNPs-H2O display better antibacterial activity, while antifungal activities are comparable between the two nanoparticle types.

Anticancer assessment and antibiofilm potential of Laetiporus sulphureus mushroom originated from Serbia

Laetiporus sulphureus (Bull.) Murrill is a well-known edible mushroom consumed in nutrition as delicacy. It has been used in traditional medicine because of its beneficial effects on human wellness, such as antimicrobial, antioxidant, and anticancer potential. The present study determined the phenolic profile of Laetiporus sulphureus ethanolic extract (LSE) by high-performance liquid chromatographic method. Tolerance of two probiotic bacterial strains Lactiplantibacillus plantarum 229v, Bifidobacterium animalis subsp. lactis and probiotic yeast Saccharomyces boulardii on LSE was analyzed in terms of viability and biofilm formation. Effects of extract on colorectal (HCT-116) and cervical (HeLa) cancer cells viability was determined using MTT test in concentration range: 1-500 μg/mL after 24 and 72 h. Redox parameters (superoxide anion radicals, nitrites, and reduced glutathione) were evaluated using NBT, Griess, and GSH assays in the concentration range of 1-500 μg/mL after 24 and 72 h. Antimigratory activity was determined by wound healing method using selected concentrations of 10 and 50 μg/mL after 24 h. Untreated cells were considered as control. As control cell line, we used healthy fibroblasts (MRC-5). Our results demonstrated abundance of LSE in phenolics, with rosmarinic acid as the main component. LSE induced low tolerance of tested planktonic probiotic strains, with no affection on their ability to form biofilm. No significant cytotoxicity on tested cancer cells was observed, with prooxidative and antimigratory effects noticed. Extract exerted significant antimigratory activity on cancer cells without effect on planktonic and probiotic cultures in biofilm. These results indicate potential application of Laetiporus sulphureus ethanolic extract as natural protector of probiotics with prominent ability to suppress cancer cell motility.

Synthesis, characterization, HSA binding, molecular docking, cytotoxicity study, and antimicrobial activity of new palladium(II) complexes with propylenediamine derivatives of phenylalanine

The four new ligands, propylenediamine derivatives of phenylalanine (R2-S,S-pddbaˑ2HCl; L1-L4) and their palladium(II) complexes (C1-C4) were synthesized and characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The interactions of new palladium(II) complexes with human serum albumin (HSA) were studied by fluorescence spectroscopy. All investigated compounds can be transported to target cells by binding to HSA, but complex C4 interacts most strongly. Molecular docking simulations were applied to comprehend the binding of the complex to the molecular target of HSA. Obtained results are in good correlations with experimental data regarding binding affinity by HSA. In vitro cytotoxicity activities were investigated on four tumor cell lines (mouse mammary (4 T1) and colon (CT26), human mammary (MDA-MD-468) and colon (HCT116)) and mouse mesenchymal stem cells as non-tumor control cells. Cytotoxic capacity was determined by MTT test and according to obtained results ligand L4 stands out as the most active and selective compound and as a good candidate for future in vivo testing. Further examination of the ligand L4 and corresponding complex C4 led to the conclusion that both induced cell death mainly by apoptosis. Ligand L4 facilitated cycle arrest in G0/G1 phase and decreased proliferative capacity of tumor cells. In vitro antimicrobial activity for ligands and corresponding Pd(II) complexes was investigated against eleven microorganisms (eight strains of pathogenic bacteria and three yeast species) using microdilution method. The minimum inhibitory concentration and minimum microbicidal concentration were determined.

Biological activities and biosorption potential of red algae (Corallina officinalis) to remove toxic malachite green dye

This research aims to use eco-friendly Corallina officinalis as an adsorbent for removing harmful malachite green dye streams from industrial effluent, promoting sustainable living and effective microbial growth inhibition. Corallina officinalis biomass was tested for textile dye biosorption, as well as its antibacterial, antioxidant, and cytotoxic properties. The effects of certain parameters, involving pH solution, initial dye concentration, algae dose, and contact time, were investigated on the sorption of dye. Fourier transform infrared spectroscopy and scanning electron microscopy were also used and, the results showed that the functional groups on the surface of algae played an important part in the biosorption process. It was noted that the kinetic data were significantly prominent by the Pseudo-second-order model with regression correlation coefficient [Formula: see text] values with an average of 0.95232. The biosorption was compatible with both the Freundlich (R2 = 0.9843), and Langmuir (R2 = 0.9653) isotherms, and the maximum removal efficiency for dye reached up to 99.9% in 2 h, 27 °C, stirring speed 120 rpm, pH 6, initial dye concentration 20 mg L-1, and biomass dose 0.03 g L-1. Corallina officinalis had higher antimicrobial activity, with values of minimum inhibitory concentrations ranging from 0.156 to 5 mg mL-1. Corallina officinalis exerted significant radical scavenging activity against tested free radicals. The extract was examined for cytotoxic activity using nine cancer cell lines, which exhibited high cytotoxicity for colon adenocarcinoma with an IC50 value of 25.895 µg mL-1.

Economic, ecological, and health aspects of β-diketonate application in the process of water purification

Water pollution is a constant challenge for humanity. Sustainable economic development and environmental protection through a green economy structure provide the opportunity to project a model of scientific, social, and economic flows. Considering new chemical use in water treatment, we tested two β-diketonates that we previously synthesized in the reaction between methyl ketone and diethyl oxalate under basic conditions. For water treatment, we used the appropriate salts of the mentioned compounds due to better solubility in water. In cooperation with the partner organizations PUC (public utility companies) Kragujevac, LTD (Private Limited Company), "Rudnik," and FIAT (Fabbrica Italiana Automobili Torino), we conducted research on their wastewater treatment. The results appeared to be more convincing in practice than the conventional methods. As a result of the study, no negative effects exerted on living organisms were found. Therefore, we are on the right track for potential application in the treatment of drinking water. Appropriate β-diketonates were tested on twelve microorganisms (isolates from the wastewater and standard strains of bacteria and yeast). One of the two tested compounds showed promising antimicrobial activity. Further investigations showed that the tested compounds significantly reduce the concentration of heavy metals, which was confirmed by statistical calculations. Also, the main advantage of this method is a small volume of waste requiring disposal, no need for driving off excess moisture, used recyclability of the coagulants, reducing hazardous waste, and therefore reducing the costs for water treatment.

The occurrence of antibiotic-resistant bacteria on the clothes of nursery teachers in daycare centres

AIMS

Childcare facilities act as microenvironments that facilitate and promote the selection, spread, and transmission of antibiotic-resistant microorganisms in the community. We focused on the study of antimicrobial resistance and genetic predispositions for β-lactamase production in bacterial isolates from nursery teachers' clothing.

METHODS AND RESULTS

Antimicrobial resistance of bacterial strains belonging to Enterobacteriaceae, Enterococcus, Staphylococcus spp., Pseudomonas spp. and Bacillus spp. isolated from 80 samples of nursery teachers' clothing was determined. The selected ESβL genes were found in 30 (44.1%) of 68 strains examined. The CTX-M type ESβL determinants were detected in 15.4%, 71.5%, and 42.5% of the Enterobacteriaceae, Pseudomonas, and Bacillus isolates, respectively. The OXA-type coding genes were detected only in strains of the genera Pseudomonas (57.1%) and Bacillus (48.6%). Thus, most B. cereus strains were sensitive to the recommended antibiotics used to treat infections caused by these bacteria. Methicillin resistance was phenotypically confirmed in 27 (14.6%) of 185 staphylococcal isolates. Four isolates (2.2%) were identified as MRSA. Vancomycin resistance was not observed in any of the staphylococcal and enterococci strains.

CONCLUSIONS

This study has shown that potential pathogens have been isolated from the clothing of nursery teachers, posing a risk of transmission to children. These clothes should be maintained and properly laundered to avoid cross-contamination and the spread of multidrug-resistant (MDR) bacteria in childcare centres.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides insight into the route of transmission of MDR microorganisms through the clothing of nursery teachers, to which greater importance should be given in the future. Proper procedures for the cleaning and use of clothing in daycare centres should be clarified and standardised.

Synthesis of series of different imidazolidine-2,4-dione derivatives and evaluation of their antimicrobial potential

A series of twenty two different imidazolidine-2,4-dione derivatives, divided according to their structure into five groups, including alkyl, alkenyl or aryl 5,5disubstituted hydantoins, spirohydantoins, and fused bicyclic and tricyclic hydantoins, was synthesized and examined for in vitro antimicrobial activity against 15 strains of bacteria and 4 strains of yeast. The antimicrobial activity was evaluated by the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) using the microdilution method. The assayed compounds exerted moderate antibacterial and weak antifungal activity. The antimicrobial activities were influenced by the structure and concentration of the tested compounds as well as the type of test microorganisms. The fused bicyclic hydantoin derivatives obtained by organoselenium induced intramolecular cyclization exhibited the highest inhibitory activity. The examined hydantoin derivatives seem as drug-like candidate for further evaluation of biological activities.

Miniaturised broth microdilution for simplified antibiotic susceptibility testing of Gram negative clinical isolates using microcapillary devices

Miniaturised antibiotic susceptibility testing: 100 times smaller microcapillary broth microdilution gives equivalent result to standard microplate broth microdilution.

Newly synthesized palladium(II) complexes with aminothiazole derivatives: in vitro study of antimicrobial activity and antitumor activity on the human prostate cancer cell line

Five new complexes of the palladium(II) ion (C1-C5) having the general formula [(PdL₂)]Cl₂ with some 2-aminothiazoles (L1-L5), where L1 = 2-amino-4-(3,4-difluorophenyl)thiazole, L2 = 2-amino-5-methyl-4-phenylthiazole, L3 = 2-amino-4-phenylthiazole, L4 = 2-amino-4-(4-chlorophenyl)thiazole, and L5 = 2-amino-4-(2,4-difluorophenyl)thiazole, have been synthesized and characterized by elemental microanalysis and infrared, ¹H NMR and ¹³C NMR spectroscopy. The in vitro antimicrobial activity of the five ligands and the corresponding Pd(II) complexes is investigated. Testing is performed by the microdilution method and the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) have been determined. Testing is conducted against 11 microorganisms (nine strains of pathogenic bacteria and two yeast species). The tested ligands and palladium(II) complexes show selective, high and moderate activity. There is a difference in antimicrobial activity between the ligands and the corresponding palladium(II) complexes. The complexes have significant anti-staphylococcal activity and activity on Pseudomonas aeruginosa which is better than the positive control. The interactions of newly synthesized palladium(II) complexes with calf thymus DNA (CT-DNA) were investigated using UV-Vis absorption and fluorescence spectroscopy. Analysis of UV-absorption and fluorescence spectra indicates the formation of a complex between the palladium(II) complexes and DNA. The high values of intrinsic binding constants, K_b, of the order 10⁴ M^-1 and Stern-Volmer quenching constants, K_SV, of the order 10⁵ M^-1 indicated very good binding of all complexes to CT-DNA. Also, the new Pd(II) complexes show high cytotoxic activity towards the human prostate cancer cell line and insignificant activity towards non-cancerous human fibroblasts. Future research could additionally explore the biological activity of Pd(II) complexes presented in this paper and investigate the possibility of their implementation in clinical practice.

Antibacterial, remineralising and matrix metalloproteinase inhibiting scandium-doped phosphate glasses for treatment of dental caries

OBJECTIVES

Antibiotic resistance is increasingly a growing global threat. This study aimed to investigate the potential use of newly developed scandium-doped phosphate-based glasses (Sc-PBGs) as an antibacterial and anticariogenic agent through controlled release of Sc³⁺ ions.

METHODS

Sc-PBGs with various calcium and sodium oxide contents were produced and characterised using thermal and spectroscopic analysis. Degradation behaviour, ion release, antibacterial action against Streptococcus mutans, anti-matrix metalloproteinase-2 (MMP-2) activity, remineralisation potential and in vivo biocompatibility were also investigated.

RESULTS

The developed glass system showed linear Sc³⁺ ions release over time. The released Sc³⁺ shows statistically significant inhibition of S. mutans biofilm (1.2 log₁₀ CFU reduction at 6 h) and matrix metalloproteinase-2 (MMP-2) activity, compared with Sc-free glass and positive control. When Sc-PBGs were mounted alongside enamel sections, subjected to acidic challenges, alternating hyper- and hypomineralisation layers consistent with periods of re- and demineralisation were observed demonstrating their potential remineralising action. Furthermore, Sc-PBGs produced a non-toxic response when implanted subcutaneously for 2 weeks in Sprague Dawley rats.

SIGNIFICANCE

Since Sc³⁺ ions might act on various enzymes essential to the biological mechanisms underlying caries, Sc-PBGs could be a promising therapeutic agent against cariogenic bacteria.

Microwave-Assisted Synthesis, Structural Characterization and Assessment of the Antibacterial Activity of Some New Aminopyridine, Pyrrolidine, Piperidine and Morpholine Acetamides

A series of new acetamide derivatives 22–28 of primary and secondary amines and para-toluene sulphinate sodium salt have been synthesized under microwave irradiation and assessed in vitro for their antibacterial activity against one Gram-positive and two Gram-negative bacterial species such as S. pyogenes, E. coli, and P. mirabilis using the Mueller-Hinton Agar diffusion (well diffusion) method. The synthesized compounds with significant differences in inhibition diameters and MICs were compared with those of amoxicillin, ampicillin, cephalothin, azithromycin and doxycycline. All of the evaluated acetamide derivatives were used with varying inhibition concentrations of 6.25, 12.5, 37.5, 62.5, 87.5, 112.5 and 125 µg/mL. The results show that the most important antibacterial properties were displayed by the synthetic compounds 22 and 24, both of bear a para-chlorophenyl moiety incorporated into the 2-position moiety of acetamide 1. The molecular structures of the new compounds were determined using the FT-IR and ¹H-NMR techniques.

Chitosan-Based Biomaterial, Calcium Hydroxide and Chlorhexidine for Potential Use as Intracanal Medication

The objective of this study was to develop a chitosan-based biomaterial with calcium hydroxide and 2% chlorhexidine for intracanal treatment application and, consequently, to diminish the number of microorganisms in the root canal system. The chitosan solution was prepared by dissolving it in 2% and 4% acetic acid (v/v) for 1 h at room temperature (25 °C) with magnetic agitation (430 rpm). Calcium hydroxide was obtained in two stages: the first was the synthesis of the calcium oxide—CaO, and the second was that of the calcium hydroxide—Ca(OH)₂. The samples were developed using different concentrations of chitosan, calcium hydroxide, and chlorhexidine 2%. They were codified as Ca(OH)₂ + Q2% (M1), Ca(OH)₂ + Q4% (M2), Ca(OH)₂ + Q2% + CLX (M3), Ca(OH)₂ + Q4% + CLX (M4), Ca(OH)₂ + Q2% + PEG (M5), and Ca(OH)₂ + Q4% + PEG (M6). They were characterized through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and rheological measurement, and the antimicrobial activity was evaluated in vitro. Characteristic absorption bands of the source materials used in this research were observed in the FTIR spectra. The X-ray diffraction technique indicated that the material has a semi-crystalline structure and that the presence of calcium hydroxide made the biomaterial more crystalline. The viscosity measurement showed a pseudoplastic behavior of the studied samples. The microbiologic analysis was positive for all samples tested, with bigger inhibition zones for the samples M3 and M4. As a result, we conclude that the formulation developed based on chitosan is promising and has potential to be an intracanal medication.

In vitro and in silico lipoxygenase inhibition studies and antimicrobial activity of pyrazolyl-phthalazine-diones

The series of pyrazolyl-phthalazine-dione derivatives (PPDs) was subjected to evaluation of their in vitro lipoxygenase (LOX) inhibition and antimicrobial activities. Results obtained for LOX inhibition activities of PPDs showed that all compounds exhibit good to excellent activity, whereby compounds with eudesmic, syringic, vanillic or toluic moiety are the most active. Molecular modelling study was performed to investigate the possible mechanism of action and binding mode of compounds within the LOX active site. Docking results revealed that activity of the examined compounds depends on the functional group ability to create hydrogen bond accepting (HBA) and hydrophobic features (Hy) in the LOX-Ib active site. In addition, all substances were tested for their antibacterial and antifungal activities. The investigated compounds showed better antifungal than antibacterial activity. The highest antifungal activity was on Aspergillus fumigatus ATTC 204305 and Trichoderma viridae ATCC 13233.

Microwave-assisted Synthesis of Novel Pyrazole Derivatives and their Biological Evaluation as Anti-Bacterial Agents

AIMS AND OBJECTIVES

Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol.

MATERIALS AND METHODS

The structural features of the synthesized compounds were characterized by melting point, FT-IR, ¹H, ¹³C NMR and elemental analysis.

RESULTS

The antibacterial activities of the synthesized pyrazoles were evaluated against three gram-positive bacteria, such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium.

CONCLUSION

All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain, and none of them demonstrated antibacterial activity against E. coli.

Molecular characterization of piezotolerant and stress-resistant mutants of Staphylococcus aureus

AIMS

In the previous work, following a pressure treatment with wild-type Staphylococcus aureus, we obtained piezotolerant isolates showing altered phenotypic characteristics. This work focuses on understanding the genetic background of their altered phenotype.

METHODS AND RESULTS

AK23, a representative piezotolerant isolate was subjected to DNA microarrays, corroborated by PCR product sequencing and revealed 10-gene deletion. All other piezotolerant isolates possessed the mutation encompassing the region from SAR0665 to SAR0674 genes (9351 bp) which was most likely the result of recombination between two homologous loci (ATTGCGGGTG) present in both genes. RNA microarray transcriptomic analysis showed that due to partial deletion of the low-affinity phosphate transporter pitA, the high-affinity PhoU-PstABCS operon was upregulated in AK23 which could be the reason for piezotolerance. Furthermore, AK23 showed low levels of the virulence gene regulator rnaIII resulting in the downregulation of several agr system genes explaining the impaired virulence characteristics of the mutant.

CONCLUSIONS

Naturally occurring mutations can result in piezotolerance which can be of a concern for high hydrostatic pressure-treated foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

A locus has been identified in piezotolerant S. aureus mutants providing insight into possible mechanisms associated with phenotypic characteristics of S. aureus. Further work should study each individual gene of the locus.

Phytochemical profiling, antioxidant and antibacterial efficacy of a native Himalayan Fern: Woodwardia unigemmata (Makino) Nakai

Present work elucidates the antioxidant and antibacterial activity of Woodwardia unigemmata (Makino) Nakai along with chemical characterization using its aqueous (AEW), methanol (MEW), and hexane (HEW) extracts. Chemical profile of different extracts was illustrated by using Gas chromatography and mass spectrometry (GC-MS) analysis. Antioxidant activities were tested using DPPH and FRAP assays, total phenolic and flavonoid content by Folin-Ciocalteu and aluminum chloride method, respectively. Further, antibacterial activity against six plant and four animal pathogenic bacteria was analyzed by employing the disc diffusion assay. GC-MS analysis revealed the presence of catechol (21.96%), glycerol (20.22%), n-pentadecanoic acid (6.95%), glyceryl monoacetate (6.35 %), ethyl acetimidate (5.39 %) and 3-hydroxy-2,3-dihydromaltol (5.36%) in AEW; β-sitosterol (17.39%), pentadecanoic acid (9.81%), vitamin E (7.82%) and glycerol (7.05%) in MEW; γ-sitosterol (33.45%), vitamin E (10.04%) and campesterol (7.32%) in HEW as major constituents. Maximum phenolics (873 ± 6.01 mgGAE/g dry extract) as well as flavonoids (151 ± 11.44 mgQE/g dry extract) content was found in MEW, which also showed remarkable antioxidant potential (IC₅₀ 6.07 ± 1.4 µg/ml for DPPH and 768 ± 10.4 mg AAE/g dry extract for FRAP assay. In antibacterial activity, maximum inhibition (15 ± 0.9 mm) was observed for HEW against R. solanacearum, followed by AEW against A. tumefaciens and X. phaseoli (11 ± 0.3 mm each). MEW was found positive only against A. tumefaciens. Significant minimum inhibitory concentration (MIC) value observed for AEW against L. monocytogenes (10 mg/ml). Polar extracts had remarkable antioxidant potential, while non-polar extract did show significant antibacterial activity. Further, GC- MS reports indicated that this traditionally useful fern species can be an excellent source of biologically active compounds.

Exploiting open source 3D printer architecture for laboratory robotics to automate high-throughput time-lapse imaging for analytical microbiology

Growth in open-source hardware designs combined with the low-cost of high performance optoelectronic and robotics components has supported a resurgence of in-house custom lab equipment development. We describe a low cost (below $700), open-source, fully customizable high-throughput imaging system for analytical microbiology applications. The system comprises a Raspberry Pi camera mounted on an aluminium extrusion frame with 3D-printed joints controlled by an Arduino microcontroller running open-source Repetier Host Firmware. The camera position is controlled by simple G-code scripts supplied from a Raspberry Pi singleboard computer and allow customized time-lapse imaging of microdevices over a large imaging area. Open-source OctoPrint software allows remote access and control. This simple yet effective design allows high-throughput microbiology testing in multiple formats including formats for bacterial motility, colony growth, microtitre plates and microfluidic devices termed ‘lab-on-a-comb’ to screen the effects of different culture media components and antibiotics on bacterial growth. The open-source robot design allows customization of the size of the imaging area; the current design has an imaging area of ~420 × 300mm, which allows 29 ‘lab-on-a-comb’ devices to be imaged which is equivalent 3480 individual 1μl samples. The system can also be modified for fluorescence detection using LED and emission filters embedded on the PiCam for more sensitive detection of bacterial growth using fluorescent dyes.

Phytochemical Evaluation, Antimicrobial and Anticancer Properties of New “Oligo Grapes” Supplement

This research presents complete data about phytochemical analysis and biological activities of a new dietary supplement for commercial use “Oligo Grapes” (OG), and its individual constituents: lyophilized pomace (LP), clay supplemented with red wine extract, lyophilized pomace ethanolic extract (PE), and red wine extract. OG, as a commercially available food supplement, has not been previously tested for its biological activity. Now we want to present new data about its phytochemical screening, antioxidant and antibacterial activities, and anticancer properties with respect to its cytotoxicity and effects on redox status in colon cancer cell lines. The tested extracts expressed strong antibacterial activity against Proteus mirabilis and Proteus mirabilis ATCC 12453, where the synergy of contents inside the supplement demonstrated a higher influence on the bacteria than its separately tested constituents. Among the investigated extracts, PE, as the extract with the highest phenolics concentration, had remarkable cytotoxic activity on HCT-116 and SW-480 colon cancer cells. Also, the treatments modulated redox status in the investigated cancer cells, by inducing oxidative and nitrosative stress, which could be one of the preferred mechanisms of the anticancer action. Based on the achieved antimicrobial and anticancer properties, there is a need for producing different food supplements and nutritional products originating from grapes. In this respect, the food supplement OG and its health benefits deserve scientific attention and further research.

In vitro antibacterial and cytogenotoxicological properties of the aqueous extract of Cymbopogoncitratus Stapf (DC) leaf

Background

Microbial infection of the genital tract or semen is one of the leading causes of male infertility. Consequently, there is a need to seek alternative products from natural sources.

Objectives

The antibacterial, phytochemical and cytogenotoxicological assessments of the aqueous extract of Cymbopogon citratus leaf were evaluated.

Methods

The antibacterial potential of the extract was done via agar-well diffusion and microdilution techniques. The phytochemical analysis was done via standard protocols.The cytogenotoxicity of the extract were analyzed using the Allium cepa assay.

Results

All test organisms were found to be sensitive to the extract except Pseudomonas. aeruginosa where no measurable zone of inhibition could be ascertained at all concentrations assessed.The highest mean inhibition diameter of 21.33±1.20mm against S. sapophyticus was recorded and a concentration-dependent susceptibility noticed. The phytochemical results revealed the presence of saponins, flavonoid, glycoside, steroids, terpenoid and alkaloids. The Alliumcepa root showed reduced mitotic indices following aconcentration-dependent increase in the extract.It can be said that the aqueous extract of C. citratus had inhibitory activities against the tested pathogenic organisms with relative anti-tumour potential.

Conclusion

This study indicated, C. citratus could be a potential source for antibacterial compounds for the possible treatment of male reproductive related infections.

Screening of crows and waterfowls for Salmonella and Listeria monocytogenes infection

Background and Aim: Wild birds can carry a number of potential human and animal pathogens. These birds can intrude into human habitats giving the opportunity to transmission of such infection. Therefore, the current study was designed to investigate the role of crows and waterfowls as vectors of Salmonella and Listeria monocytogenes and to compare cultivation methods with direct polymerase chain reaction (PCR) for the detection of infection. Materials and Methods: A total of 200 fecal dropping samples were collected. Salmonella was cultivated by three step method (Universal Pre-enrichment Broth [UPB], Rappaport-Vassiliadis Broth, and Xylose Lysine Desoxycholate agar). The recovered isolates were characterized by biotyping, serotyping, and PCR detection of enterotoxin (stn) gene. The antibiogram pattern of isolates against a panel of 8 antibiotics was recorded. L. monocytogenes was cultivated on UPB, then on Listeria Oxford Agar and Listeria CHROMagar. The recovered isolates were characterized by biotyping and PCR detection of listeriolysin (hylA) gene. Results: The percentages of Salmonella infection in crows and waterfowls were 10 and 20, respectively. The most frequently recovered serovars were Typhimurium, Potengi, Enteritidis, and Kentucky. Antimicrobial susceptibility analysis of Salmonella isolates showed that the resistance rates for gentamicin were the highest (92%), followed by amoxicillin (88%) and cefixime (60%). Resistance to 8 antibiotics was recorded in 60% (15/25) of Salmonella isolates. The percentages of L. monocytogenes infection in crows and waterfowls were 1.3 and 2, respectively. Direct PCR applied to UPB revealed that 12% and 3% of samples were positive for Salmonella and L. monocytogenes, respectively, and there was no significant difference between direct PCR and cultivation method for the detection of infection. Conclusion: The present findings indicate that wild birds can harbor zoonotic enteric pathogens and this necessitates monitoring the epidemiologic status of these pathogens among wild birds and humans and applying the appropriate intervention measures to prevent the spread of infection.

Genomic Surveillance of Enterococcus faecium Reveals Limited Sharing of Strains and Resistance Genes between Livestock and Humans in the United Kingdom

The rise in rates of human infection caused by vancomycin-resistant Enterococcus faecium (VREfm) strains between 1988 to the 2000s in Europe was suggested to be associated with acquisition from livestock. As a result, the European Union banned the use of the glycopeptide drug avoparcin as a growth promoter in livestock feed. While some studies reported a decrease in VREfm in livestock, others reported no reduction. Here, we report the first livestock VREfm prevalence survey in the UK since 2003 and the first large-scale study using whole-genome sequencing to investigate the relationship between E. faecium strains in livestock and humans. We found a low prevalence of VREfm in retail meat and limited evidence for recent sharing of strains between livestock and humans with bloodstream infection. There was evidence for limited sharing of genes encoding antibiotic resistance between these reservoirs, a finding which requires further research.

Vancomycin-resistant Enterococcus faecium (VREfm) is a major cause of nosocomial infection and is categorized as high priority by the World Health Organization global priority list of antibiotic-resistant bacteria. In the past, livestock have been proposed as a putative reservoir for drug-resistant E. faecium strains that infect humans, and isolates of the same lineage have been found in both reservoirs. We undertook cross-sectional surveys to isolate E. faecium (including VREfm) from livestock farms, retail meat, and wastewater treatment plants in the United Kingdom. More than 600 isolates from these sources were sequenced, and their relatedness and antibiotic resistance genes were compared with genomes of almost 800 E. faecium isolates from patients with bloodstream infection in the United Kingdom and Ireland. E. faecium was isolated from 28/29 farms; none of these isolates were VREfm, suggesting a decrease in VREfm prevalence since the last UK livestock survey in 2003. However, VREfm was isolated from 1% to 2% of retail meat products and was ubiquitous in wastewater treatment plants. Phylogenetic comparison demonstrated that the majority of human and livestock-related isolates were genetically distinct, although pig isolates from three farms were more genetically related to human isolates from 2001 to 2004 (minimum of 50 single-nucleotide polymorphisms [SNPs]). Analysis of accessory (variable) genes added further evidence for distinct niche adaptation. An analysis of acquired antibiotic resistance genes and their variants revealed limited sharing between humans and livestock. Our findings indicate that the majority of E. faecium strains infecting patients are largely distinct from those from livestock in this setting, with limited sharing of strains and resistance genes.

Clinical and Molecular Correlates of Escherichia coli Bloodstream Infection from Two Geographically Diverse Centers in Rochester, Minnesota, and Singapore

Escherichia coli bacteremia is caused mainly by sequence type complex 131 (STc131) and two clades within its fluoroquinolone-resistance-associated H30 subclone, H30R1 and H30Rx. We examined clinical and molecular correlates of E. coli bacteremia in two geographically distinct centers. We retrospectively studied 251 unique E. coli bloodstream isolates from 246 patients (48 from the Mayo Clinic, Rochester, MN [MN], and 198 from Tan Tock Seng Hospital, Singapore [SG]), from October 2013 through March 2014. Isolates underwent PCR for phylogroup, STc, bla_CTX-M type, and virulence gene profiles, and medical records were reviewed. Although STc131 accounted for 25 to 27% of all E. coli bacteremia isolates at each site, its extended-spectrum-β-lactamase (ESBL)-associated H30Rx clade was more prominent in SG than in MN (15% versus 4%; P = 0.04). In SG only, patients with STc131 (versus other E. coli STc isolates) were more likely to receive inactive initial antibiotics (odds ratio, 2.8; P = 0.005); this was true specifically for patients with H30Rx (odds ratio, 7.0; P = 0.005). H30Rx comprised 16% of community-onset bacteremia episodes in SG but none in MN. In SG, virulence scores were higher for H30Rx than for H30R1, non-H30 STc131, and non-STc131 isolates (P < 0.02 for all comparisons). At neither site did mortality differ by clonal status. The ESBL-associated H30Rx clade was more prevalent and more often of community onset in SG, where it predicted inactive empirical treatment. The clonal distribution varies geographically and has potentially important clinical implications. Rapid susceptibility testing and clonal diagnostics for H30/H30Rx might facilitate earlier prescribing of active therapy.

Characterization and zoonotic impact of Shiga toxin producing Escherichia coli in some wild bird species

Aim:

Wild birds are considered silent vectors of some zoonotic water and food borne pathogens of public health significance. Owing to the importance of Shiga toxin producing Escherichia coli (STEC) as the most pathogenic among the emerging diarrheagenic E. coli groups that can infect man; the present study was designed to detect the occurrence of STEC among wild birds in Egypt.

Materials and Methods:

A total of 177 intestinal content swab samples originating from five wild bird species were investigated for the presence of E. coli and STEC by standard culture methods. Suspect STEC isolates were further characterized by serotyping, random amplified polymorphic DNA polymerase chain reaction (RAPD PCR), antimicrobial resistance pattern and PCR detection of stx₁, stx₂, and eae genes.

Results:

A total of 30 suspect STEC isolates from 30 positive birds’ samples were detected and identified on STEC CHROMagar (semi-captive pigeons, 15; house crows, 8; cattle egrets, 3; moorhens, 2; and house teals, 2). 25 isolates were grouped into 13 serogroups (O:20, O:25, O:26, O:27, O:63, O:78, O:111, O:114, O:125, O:128, O:142, O:153, and O:158), while five were rough strains. The distribution of STEC virulence genes among wild birds was as follows: 16 birds carried stx₁ gene only (nine pigeons [28.1%], six crows [7.1%], and one cattle egret [5.6%]). Stx₁ and stx₂ genes together were detected in four birds (one cattle egret [5.6%], two moorhens [6.1%], and one house teal, [10%]). Only one pigeon (3.1%) possessed the three alleles. Disk diffusion test results showed that cefixime was the most effective against STEC serotypes with (93.3%) sensitivity, followed by gentamycin (56.7%), and amoxicillin (50%). On the other hand, all the recovered STEC isolates were resistant to cefotaxime, doxycycline, cephalothin, and sulfisoxazole. RAPD fingerprinting using primers OPA-2 and OPA-9 showed that STEC isolates were heterogeneous; they yielded 30 and 27 different clusters, respectively.

Conclusions:

Wild birds carry STEC and may add to the contamination of the surrounding environment.

Complex Routes of Nosocomial Vancomycin-Resistant Enterococcus faecium Transmission Revealed by Genome Sequencing

BACKGROUND

Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of nosocomial infection. Here, we describe the utility of whole-genome sequencing in defining nosocomial VREfm transmission.

METHODS

A retrospective study at a single hospital in the United Kingdom identified 342 patients with E. faecium bloodstream infection over 7 years. Of these, 293 patients had a stored isolate and formed the basis for the study. The first stored isolate from each case was sequenced (200 VREfm [197 vanA, 2 vanB, and 1 isolate containing both vanA and vanB], 93 vancomycin-susceptible E. faecium) and epidemiological data were collected. Genomes were also available for E. faecium associated with bloodstream infections in 15 patients in neighboring hospitals, and 456 patients across the United Kingdom and Ireland.

RESULTS

The majority of infections in the 293 patients were hospital-acquired (n = 249) or healthcare-associated (n = 42). Phylogenetic analysis showed that 291 of 293 isolates resided in a hospital-associated clade that contained numerous discrete clusters of closely related isolates, indicative of multiple introductions into the hospital followed by clonal expansion associated with transmission. Fine-scale analysis of 6 exemplar phylogenetic clusters containing isolates from 93 patients (32%) identified complex transmission routes that spanned numerous wards and years, extending beyond the detection of conventional infection control. These contained both vancomycin-resistant and -susceptible isolates. We also identified closely related isolates from patients at Cambridge University Hospitals NHS Foundation Trust and regional and national hospitals, suggesting interhospital transmission.

CONCLUSIONS

These findings provide important insights for infection control practice and signpost areas for interventions. We conclude that sequencing represents a powerful tool for the enhanced surveillance and control of nosocomial E. faecium transmission and infection.

Antibacterial and cytotoxic activities of naphthoquinone pigments from Onosma visianii Clem

In this study, the antibacterial and cytotoxic activities of isolated compounds from the roots of Onosma visianii were investigated. By using different chromatographic techniques and appropriate spectroscopic methods, the seven naphthoquinones were described: deoxyshikonin (1), isobutyrylshikonin (2), α-methylbutyrylshikonin (3), acetylshikonin (4), β-hydroxyisovalerylshikonin (5), 5,8-O-dimethyl isobutyrylshikonin (6) and 5,8-O-dimethyl deoxyshikonin (7). Among the tested compounds, 3 and 4 exhibited the highest antibacterial activities toward all tested bacterial species (MIC₅₀ and MIC₉₀ for gram positive bacteria: 6.40 μg/mL-12.79 μg/mL and 6.82 μg/mL-13.60 μg/mL, respectively; for gram negative bacteria: 4.27 μg/mL-8.53 μg/mL and 4.77 μg/mL-9.54 μg/mL, respectively). Also, naphthoquinones 3 and 4 exhibited strong cytotoxic activity against MDA-MB-231 cells (IC₅₀ values 86.0 μg/mL and 80.2 μg/mL, respectively), while compounds 1, 3, 4 and 5 significantly decreased viability of HCT116 cells (IC₅₀ values of 97.8 μg/mL, 15.2 μg/mL, 24.6 μg/mL and 30.9 μg/mL, respectively). Our results indicated that all tested naphthoquinone pigments are potential candidates for clinical uses as antibacterial and cytotoxic agents.