fac-Re(CO)3-based neutral heteroleptic tetrahedrons.

Four new flexible ditopic nitrogen donors possessing a xylene spacer and 2-phenylbenzimidazolyl or its derivatives as a coordinating unit and one rigid bis-chelating ligand consisting of two 2-hydroxyphenylbenzimidazolyl motifs and a central phenylene spacer were synthesized and further used with Re2(CO)10 for making a new family of neutral, heteroleptic tetrahedral-shaped supramolecular coordination complexes via a one-pot approach. The new ligands and the complexes were characterized using various analytical and spectroscopic methods. The molecular structures of the complexes were determined using single crystal X-ray diffraction analysis, which reveal that four rhenium cores are arranged in the vertices, and four ligands are at the edges of the tetrahedron.

Sulfate Donor Based Dinuclear Heteroleptic Triple-Stranded Helicates from Sulfite and Ditopic Nitrogen Donor Ligands and Their Transformation to Dinuclear Homoleptic Double-Stranded Mesocates.

Sulfate donor based supramolecular coordination complexes [{ fac-Re(CO)3}(µ-SO4)(L n)2{ fac-Re(CO)3}] (1-3) were obtained using ditopic N donors (L n; n = 1-3), NaHSO3, and Re2(CO)10 in a one-pot, multicomponent, coordination-driven self-assembly approach, in which SO32- becomes oxidized to SO42- during the reaction and acts as a building framework. Complexes 1-3 were characterized using IR, ESI-TOF-MS, and 1H NMR spectroscopy. The structures of complexes 1-3 were confirmed using single-crystal X-ray diffraction analysis. The transformation of the dinuclear heteroleptic triple-stranded helicate to the dinuclear homoleptic double-stranded mesocate [{Re(CO)3Cl}2(L n)2] (L n = L1, L2, L3; 4a-6a) was achieved by the addition of BaCl2. The direct treatment of Re(CO)5X (X = Cl, Br) with L1/L2/L3 yielded the dinuclear homoleptic double-stranded helicates [{Re(CO)3X}2 (L n)2] (4b-6b and 7-9).

Zinc oxide-curcumin nanocomposite loaded collagen membrane as an effective material against methicillin-resistant coagulase-negative Staphylococci.

Zinc oxide nanoparticles and curcumin are excellent antimicrobial agents. They have the potential to be used as alternative to antibiotics in wound infection management. In this study, ZnO-curcumin nanocomposite was synthesized and characterized. Physical adsorption of the nanocomposite onto collagen skin wound dressing was conducted and structural investigation was carried out by SEM. Antimicrobial assay, minimum inhibitory concentration (MIC), and viability assays of different concentrations of nanocomposite loaded collagen membrane were conducted against clinically isolated methicillin-resistant coagulase-negative Staphylococci (MRCoNS), such as S. epidermidis, S. hemolyticus, and S. saprophyticus. The nanocomposite showed excellent anti-CoNS activity on time kill assay with the MIC value of 195 µg/mL against S. epidermidis, S. hemolyticus and 390 µg/mL against S. saprophyticus. The nanocomposite loaded collagen membrane also showed excellent in vitro antistaphylococcal activity. This study may lead to the development of antibiotic alternate strategies to control and limit the MRCoNS in wound-related infections.

Endophytic Nocardiopsis sp. from Zingiber officinale with both antiphytopathogenic mechanisms and antibiofilm activity against clinical isolates.

Novel and potential antimicrobial compounds are essential to tackle the frequently emerging multidrug-resistant pathogens and also to develop environment friendly agricultural practices. In the current study, endophytic actinomycetes from rhizome of Zingiber officinale were explored in terms of its diversity and bioactive properties. Fourteen different organisms were isolated, identified and screened for activity against Pythium myriotylum and human clinical pathogens. Among these, Nocardiopsis sp. ZoA1 was found to have highest inhibition with excellent antibacterial effects compared to standard antibiotics. Remarkable antibiofilm property was also shown by the extract of ZoA1. Its antifungal activity against Pythium and other common phytopathogens was also found to be promising as confirmed by scanning electron microscopic analysis. By PCR-based sequence analysis of phz E gene, the organism was confirmed for the genetic basis of phenazine biosynthesis. Further GC-MS analysis of Nocardiopsis sp. revealed the presence of various compounds including Phenol, 2,4-bis (1,1-dimethylethyl) and trans cinnamic acid which can have significant role in the observed result. The current study is the first report on endophytic Nocardiopsis sp. from ginger with promising applications. In vivo treatment of Nocardiopsis sp. on ginger rhizome has revealed its inhibition towards the colonization of P. myriotylum which makes the study to have promises to manage the severe diseases in ginger like rhizome rot.

Virulence factors associated with Coagulase Negative Staphylococci isolated from human infections.

Infections caused by commensal organisms by changing to infectious life style generate much challenge to the current treatment strategies. Coagulase Negative Staphylococci (CoNS) are one of them, with their coexisting biofilm forming and multiple antibiotic resistance properties form important agents of nosocomial infection. To evaluate species distribution, biofilm formation, and antibiogram, CoNS isolates from various clinical samples were isolated. The presence of biofilm and associated genes icaAB, aap, atlE, embp, bhp, and fbe in CoNS was screened by PCR. The biofilm chemical composition and its correlation with the genotypes were also analysed. Staphylococcus epidermidis (59%) was found to be the most prevalent CoNS species. Most of the CoNS isolates harboring biofilm gene showed carbohydrate-protein-eDNA biofilm, whereas carbohydrate-protein biofilms were also observed. High percentage of multiple drug resistance, and biofilm gene frequency among these CoNS isolates point towards the need of periodic surveillance as CoNS are recently identified to cause difficult to treat infections.

Studies on coexistence of mec gene, IS256 and novel sasX gene among human clinical coagulase-negative staphylococci.

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) are major nosocomial pathogens which cause device-related infections. Presence of various virulence factors along with methicillin resistance favor improved CoNS pathogenicity and their dissemination among population. In the present study, mec gene prevalence was analyzed along with SCC mec diversity among 55 human clinical CoNS isolates. PCR screening of insertion sequence (IS256) was also conducted to elucidate their association with methicillin resistance among selected CoNS species. In addition to this, PCR screening and sequence analysis of novel colonization-associated gene sasX was also carried out. High incidences of mec gene, IS256 and their association have been noted among all of the CoNS species tested. Interestingly, eight CoNS isolates were found to harbor sasX gene including S. epidermidis, S. hemolyticus and S. saprophtyicus species. Remarkably they were also found to have the coexistence of mec gene and IS256 in their genome. Increased SCC mec diversity with non-typeable elements was also observed among CoNS isolates. Presence of sasX gene in CoNS with mec gene and insertion sequence 256 and also the identification of non-typeable SCC mec element make the study novel and interesting.

Electrospun Polycaprolactone Membrane Incorporated with Biosynthesized Silver Nanoparticles as Effective Wound Dressing Material.

Biosynthesized silver nanoparticles (AgNPs) incorporated polycaprolactone (PCL) nanomembrane was prepared by electrospinning as a cost-effective nanocomposite for application as an antimicrobial agent against wound infection. The nanocomposite membrane was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis and Scanning Electron microscopy (SEM). The hydrophilicity analysis of electrospun membranes as evaluated by water contact angle measurement showed the change of hydrophobicity of PCL to hydrophilic upon incorporation of silver nanoparticles. Better mechanical properties were also observed for PCL membrane due to the incorporation of silver nanoparticles and are highly supportive to explore its biomedical applications. Further antibacterial analysis of silver nanoparticle-incorporated PCL membrane against common wound pathogens coagulase-negative Staphylococcus epidermidis and Staphylococcus haemolyticus showed remarkable activity. As biosynthesized AgNPs are least explored for clinical applications, the current study is a promising cost-effective method to explore the development of silver nanoparticle-based electrospun nanocomposite to resist wound-associated infection.

Inhibitory effect of silver nanoparticle fabricated urinary catheter on colonization efficiency of Coagulase Negative Staphylococci.

Multiple antibiotic resistance and diverse mechanisms for biofilm formation make Coagulase Negative Staphylococci (CoNS) to cause infections associated with insertion of medical devices. As the infectious life style of CoNS pose difficult to treat conditions, materials with multitargeted antimicrobial effect can offer promising ways to modify the surface of devices to limit microbial growth. The broad spectrum of antimicrobial properties shown by silver nanoparticles (AgNPs) make it as an excellent candidate to act on device surface as persistent antimicrobial structures. In the current study, AgNPs assembled by soil bacteria under visible light at room temperature were analysed for its physical properties by UV-Vis spectroscopy, FTIR, SEM, HR-TEM and EDS and they also showed significant antimicrobial and antibiofilm properties against selected members of CoNS like Staphylococcus epidermidis and Staphylococcus haemolyticus. Very interestingly, further analysis on antibacterial mechanism of AgNPs showed their remarkable ability to cause disorganization of bacterial cell membrane. Further, surface engineering application of AgNPs on urinary catheter showed its excellent potential to prevent the attachment and colonization of CoNS which make result of study with significantly novel medical applications.

Chronic mania: an underrecognized clinical entity.

Chronic mania (defined as the presence of manic symptoms for more than 2 years without remission) poses significant problems in diagnosis and management. Generally it denotes poor outcome, though contrary reports are available. We present a case of chronic mania and discuss the clinical features of chronic mania reported in the literature, which are useful in distinguishing chronic mania from acute mania.