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Background: Today, Methicillin-Resistant Staphylococcus Aureus (MRSA) has become one of the public health concerns due to its resistance to antimicrobial drugs, and this problem makes treating patients with infections caused by this bacterium difficult. Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains are pervasive in both community and hospital settings, primarily attributable to Staphylococcus aureus' capacity to colonize areas like the nose or skin. In this study, with the aim of comparing phenotypic (disc diffusion method) and genotypic (PCR) methods, to detect methicillin-resistant Staphylococcus aureus isolated from patients of hospitals under supervision of Tehran university of medical sciences, and also detection of nor A, that is the one of the most important genes in efflux pump cluster genes. Methods: The present research was a cross- sectional study that was conducted from February 2022 to September 2023. In this research, 43 isolated strains of Staphylococcus aureus from wound discharge and blood samples, were collected from different departments of Tehran hospitals and had submitted to the research laboratory of the school of allied medical sciences in Tehran university of medical sciences. After identifying the strains, the resistance of the isolates to 14 types of antibiotics was checked by disk diffusion method. Results: Staphylococcus aureus diagnostic tests including gram staining on colonies, catalase, coagulase, DNase tests were performed and it was found that all strains were Staphylococcus aureus. In the next step, all samples were resistant to Cloxacillin by disc diffusion method, and the presence of mec A gene in them was confirmed by PCR method, thus the presence of MRSA strains was confirmed from the genotypic point of view. Of the 43 Staphylococcus aureus strains, 26 samples were identified as having the nor A gene by PCR and electrophoresis. Conclusion: The results of the present research have shown that the prevalence of Staphylococcus aureus bacteria in hospital samples is significant and resistance to methicillin and ciprofloxacin has increased in the strains of this bacteria.

Nonoperating room anesthesia (NORA) refers to the practice and administration of anesthesia or sedation outside the operating room (OR), which has been increasingly implemented in practice. The novelty of NORA is to separate the anesthesia preoperative stage from an OR for the sake of saving OR time and improving its efficiency. In this article, we study the scheduling problem for NORA considering both anesthetic rooms (ARs) and operating rooms (ORs) based on ambiguous information about surgical durations. Our goal is to devise a robust and efficient scheduling mechanism for NORA. To address this problem, we develop a two‐stage mixed‐integer Robust Optimization (RO) model that minimizes the total costs, including the sum of operating costs of opened ORs and ARs, delay cost of surgeries, and overtime cost of ORs. Decisions include the number of ARs and ORs to open, the allocation of patients to ARs and ORs, the sequence of surgeries, and the planned starting time for each surgery. Accordingly, a heuristic algorithm, so‐called column‐and‐constraint generation (C&CG), is developed that renders a desirable performance. Some salient properties of the problem are also discussed. In addition, by leveraging practical data in conjunction with data reported in the extant research, the computational efficacy of the proposed algorithm is verified under various sets of parameters. Our numerical experiments reveal that (1) the implementation of NORA can reduce the OR overtime cost and the waiting time of patients; (2) our proposed Robust Optimization (RO) model possesses stronger robustness and computational efficiency than the distributionally robust model (DRO); and (3) while considering surgical duration uncertainty, the developed scheduling approach outperforms the corresponding deterministic setting in terms of decreasing the total cost and alleviating the surgery delay. Generally, the proposed approach is more adaptive to take the advantage of the surgical duration uncertainty to enhance its efficacy. [ABSTRACT FROM AUTHOR]

Introduction: Although fluoroquinolones are used to treat methicillin-resistant Staphylococcus aureus (MRSA)-induced infections, acquisition of antibiotic resistance by bacteria has impaired their clinical relevance. We aimed to evaluate the frequency of norA, norB, and norC efflux pump genes-mediating fluoroquinolones resistance and measure their expression levels in MRSA isolates. Methodology: 126 S. aureus isolates were collected from different clinical samples of adult hospitalized patients and identified by conventional microbiological methods. MRSA was diagnosed by cefoxitin disc diffusion method and minimum inhibitory concentration (MIC) of ciprofloxacin by broth microdilution method. The expression levels of efflux pump genes were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Results: 80 (63.5%) MRSA isolates were identified and showed high level of resistance to erythromycin (80%), gentamicin (75%), clindamycin (65%) and ciprofloxacin (60 %). norA, norB, and norC were detected in 75%, 35% and 55% of the MRSA isolates respectively. norC was the most commonly overexpressed gene measured by qRT-PCR, occurring in 40% of MRSA isolates, followed by norA (35%) and norB (30%). The expression of these genes was significantly higher in ciprofloxacin-resistant than quantitative real-time PCR ciprofloxacin-sensitive MRSA isolates. Conclusions: This study showed high prevalence and overexpression of efflux pump genes among MRSA isolates which indicates the significant role of these genes in the development of multidrug resistance against antibiotics including fluoroquinolones. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus leads to diverse infections, and their treatment relies on the use of antibiotics. Nevertheless, the rise of antibiotic resistance poses an escalating challenge and various mechanisms contribute to antibiotic resistance, including modifications to drug targets, enzymatic deactivation of drugs, and increased efflux of antibiotics. Hence, the quest for innovative antimicrobial solutions has intensified in the face of escalating antibiotic resistance and the looming threat of superbugs. The NorA protein of S. aureus, classified as an efflux pump within the major facilitator superfamily, when overexpressed, extrudes various substances, including fluoroquinolones (such as ciprofloxacin) and quaternary ammonium. Addressing this, the unexplored realm of inorganic and organometallic compounds in medicinal chemistry holds promise. Notably, the study focused on investigating two different series of palladium-based metal complexes consisting of QSL_PA and QSL_PB ligands to identify a potent NorA efflux pump inhibitor that can restore the susceptibility to fluoroquinolone antibiotics. QSL_Pd5A was identified as a potent efflux pump inhibitor from the real-time efflux assay. QSL_Pd5A also resensitized SA1199B to ciprofloxacin at a low concentration of 0.125 µg/mL without elucidating cytotoxicity on the NRK-62E cell line. The in vitro findings were substantiated by docking results, indicating favorable interactions between QSL_Pd5A and the NorA efflux pump. [ABSTRACT FROM AUTHOR]

: This research article explores the use of traditional Nora performing arts practice in the muscular development of autistic children. It is hoped that this initial exploration can lead to further developments in the use of traditional cultural practices for helping autistic children. Six Nora dance activities were created and implemented with eleven autistic children aged 5 to 11 at the Rajanukul Institute, Department of Mental Health, Ministry of Public Health, Thailand. The activities were practiced three times a week for forty-five minutes per session. The course lasted eight weeks. The gross motor skills of the children were assessed using PDMS-2 evaluation before the course, in the fourth week, and at the end of the course. Data were analyzed using statistical software (SPSS for Windows) to determine the standard deviation and Friedman test results. The findings show that there was a statistically significant difference between the average balance and stability of the samples from the pre-activity to the fourth and eighth weeks of the course. The students displayed improved and more stabilized body control after completing the Nora course. It can be concluded that Nora activities designed for use with autistic children can have a positive impact on the development of movement behaviors, muscle strength, and concentration. [ABSTRACT FROM AUTHOR]

Background: Little is known about susceptibility of Staphylococcus lugdunensis to antiseptics. The objective of this study was to evaluate, at the molecular and phenotypic level, the susceptibility of 49 clinical S. lugdunensis strains (belonging to the seven clonal complexes [CCs] defined by multilocus sequence typing) to two antiseptics frequently used in healthcare settings (chlorhexidine digluconate [CHX] and chloride benzalkonium [BAC]). Results: The minimum inhibitory concentrations (MICs), by broth microdilution method, varied for BAC from 0.25 mg/L to 8 mg/L (MIC50 = 1 mg/L, MIC90 = 2 mg/L) and for CHX from 0.5 mg/L to 2 mg/L (MIC50 = 1 mg/L, MIC90 = 2 mg/L). The BAC and CHX minimum bactericidal concentrations (MBCs) varied from 2 mg/L to 8 mg/L (MBC50 = 4 mg/L, MBC90 = 8 mg/L) and from 2 mg/L to 4 mg/L (MBC50 and MBC90 = 4 mg/L), respectively. A reduced susceptibility to CHX (MIC = 2 mg/L) was observed for 12.2% of the strains and that to BAC (MIC ≥ 4 mg/L) for 4.1%. The norA resistance gene was detected in all the 49 isolates, whereas the qacA gene was rarely encountered (two strains; 4.1%). The qacC, qacG, qacH, and qacJ genes were not detected. The two strains harboring the qacA gene had reduced susceptibility to both antiseptics and belonged to CC3. Conclusion: The norA gene was detected in all the strains, suggesting that it could belong to the core genome of S. lugdunensis. S. lugdunensis is highly susceptible to both antiseptics tested. Reduced susceptibility to BAC and CHX was a rare phenomenon. Of note, a tendency to higher MICs of BAC was detected for CC3 isolates. These results should be confirmed on a larger collection of strains. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus leads to diverse infections, and their treatment relies on the use of antibiotics. Nevertheless, the rise of antibiotic resistance poses an escalating challenge and various mechanisms contribute to antibiotic resistance, including modifications to drug targets, enzymatic deactivation of drugs, and increased efflux of antibiotics. Hence, the quest for innovative antimicrobial solutions has intensified in the face of escalating antibiotic resistance and the looming threat of superbugs. The NorA protein of S. aureus, classified as an efflux pump within the major facilitator superfamily, when overexpressed, extrudes various substances, including fluoroquinolones (such as ciprofloxacin) and quaternary ammonium. Addressing this, the unexplored realm of inorganic and organometallic compounds in medicinal chemistry holds promise. Notably, the study focused on investigating two different series of palladium-based metal complexes consisting of QSL_PA and QSL_PB ligands to identify a potent NorA efflux pump inhibitor that can restore the susceptibility to fluoroquinolone antibiotics. QSL_Pd5A was identified as a potent efflux pump inhibitor from the real-time efflux assay. QSL_Pd5A also resensitized SA1199B to ciprofloxacin at a low concentration of 0.125 µg/mL without elucidating cytotoxicity on the NRK-62E cell line. The in vitro findings were substantiated by docking results, indicating favorable interactions between QSL_Pd5A and the NorA efflux pump.

Non-operating room anaesthesia (NORA) refers to the administration of anaesthesia outside of the traditional operating room environment. This may include procedures performed in the radiology department, interventional cardiology suites, or endoscopy units. With the increasing demand for minimally invasive procedures, the requirement to provide anaesthesia outside the theatre environment is becoming more common. Non-operating room anaesthesia provides a unique set of challenges including airway management, monitoring, procedural access, patient positioning, temperature management, delivery of anaesthesia and management of complications. This review will consider these aspects and provide a guide to the safe implementation of non-operating room anaesthesia. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus can exhibit resistance to various antibiotics. Among its resistance mechanisms, the active efflux of antibiotics can be seen as relevant. This study aimed to evaluate the ability of resveratrol to modulate norfloxacin resistance in S. aureus. The antimicrobial activity of resveratrol was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC). Then, the modulatory effect of resveratrol was evaluated using the MIC determination for the antibiotic or ethidium bromide in the presence and absence of resveratrol at a sub-MIC level. The MIC of norfloxacin against S. aureus SA1199B (NorA-overexpressing strain) decreased 16-fold when in the presence of resveratrol, with a similar behavior being observed for ethidium bromide. An evaluation of the ethidium bromide accumulation was also performed, showing that in the presence of resveratrol, the SA1199B strain had augmented fluorescence due to the accumulation of ethidium bromide. Altogether, the results suggested that resveratrol may act by inhibiting NorA. These in vitro data were supported by docking results, with interactions between resveratrol and the NorA efflux pump predicted to be favorable. Our findings demonstrated that resveratrol may modulate norfloxacin resistance through the inhibition of NorA, increasing the effectiveness of this antibiotic against S. aureus. [ABSTRACT FROM AUTHOR]

One promising approach in treating antibiotic-resistant bacteria is to "break" resistances connected with antibacterial efflux by co-administering efflux pump inhibitors (EPIs) with antibiotics. Here, ten compounds, previously optimized to restore the susceptibility to ciprofloxacin (CIP) of norA-overexpressing Staphylococcus aureus, were evaluated for their ability to inhibit norA-mediated efflux in Staphylococcus pseudintermedius and synergize with CIP, ethidium bromide (EtBr), gentamycin (GEN), and chlorhexidine digluconate (CHX). We focused efforts on S. pseudintermedius as a pathogenic bacterium of concern within veterinary and human medicine. By combining data from checkerboard assays and EtBr efflux inhibition experiments, the hits 2-arylquinoline 1, dihydropyridine 6, and 2-phenyl-4-carboxy-quinoline 8 were considered the best EPIs for S. pseudintermedius. Overall, most of the compounds, except for 2-arylquinoline compound 2, were able to fully restore the susceptibility of S. pseudintermedius to CIP and synergize with GEN as well, while the synergistic effect with CHX was less significant and often did not show a dose-dependent effect. These are valuable data for medicinal chemistry optimization of EPIs for S. pseudintermedius and lay the foundation for further studies on successful EPIs to treat staphylococcal infections. [ABSTRACT FROM AUTHOR]

In Henrik Ibsen’s A Doll’s House, Nora’s departure from home being hurt by her husband’s behavior appears to be the most important event of the drama igniting so far a wide critical parlances of Feminist array that appreciate the departure as Nora’s freedom from male-dominated society. But Nora’s success in having a home of comfort and happiness in her post-departure future life in Feminist world deserves critical attention too. We may posit Nora will shift to a Feminist world considering the departure as the manifestation of her newly imbibed Feminist spirit because the first wave Feminism of her time is either indifferent about or antagonistic to family life by being politics-centric. However, when Nora has within her a woman’s indispensable family-centric female construction to face nonfamilial politics-centric first wave feminism, she is sure to find no home in that Feminist world. Thus, this paper aims at examining how Nora, with her declared departure from home, is going to shift to the world of first wave Feminism which, by being nonfamilial and politics-centric, works against the very family-centric construction of Nora’s female construction and offers homelessness to her.

An increasing number of patients are receiving sedation or anaesthesia in locations outside of the operating room. Compared with the operating room, anaesthesia providers working in a non-operating room anaesthesia (NORA) location report significantly lower perceived levels of safety, and higher levels of anxiety, stress, and workload. These results are likely to affect the well-being of staff in NORA locations and are clinically relevant in terms of patient safety. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the presence of volcanic pozzolans in the structural mortars of the Roman Temple of Nora in Sardinia (3rd c. AD), represented by pyroclastic rocks (pumices and tuffs) employed as coarse and fine aggregates. The provenance of these materials from the Phlegraean Fields was highlighted through a multi-analytical approach, involving Polarized Light Microscopy on thin sections (PLM), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), Quantitative Phase Analysis by X-ray Powder Diffraction (QPA-XRPD), and X-ray Fluorescence (XRF) investigations. These volcanic pozzolans, outcropping in the Bay of Naples between Pozzuoli and the Vesuvius, are traditionally associated with the pulvis puteolana, the famous pozzolanic ash prescribed by Vitruvius and Pliny in order to confer strength and waterproofing capabilities to ancient concretes. This is the first evidence of the trade of this volcanic material from the Neapolitan area to Sardinia, starting at least by the Middle Imperial Age. The use of the pulvis puteolana in the Roman Temple of Nora seems primarily targeted to strengthen above-ground masonries, while waterproofing capabilities were not strictly pursued. This opens new questions about the construction reasons for which the demand and commercialization for this product was intended. [ABSTRACT FROM AUTHOR]

This essay stages a dialogue between Lu Xun and Eileen Chang on the figure of Nora, a global icon of the burgeoning New Woman from Henrik Ibsen's A Doll's House. Although often thought of as belonging to diametrically opposing camps – Lu Xun political and Chang apolitical, Lu Xun a sharp critic of women's oppression and Chang a self-conscious performer of femininity in writing style and personal styling – I argue that their concerns converge more often than one would expect, in their trenchant social critique as well as in the ways their celebrated realism unfolds into allegories of modern Chinese history. At the same time, the points of their divergence also provide us a window onto the gendered positioning of each writer and their different responses to the formation of modern subjectivity. On whether Nora should leave and where she is going, the different answers given by Lu Xun and Eileen Chang illuminate the conditions, limitations and pitfalls of this gendered subject, whose ambulatory-ness serves as a foundational metaphor of her modernity and self-determination. [ABSTRACT FROM AUTHOR]

NorA is one of the main native MDR efflux pumps of Staphylococcus aureus, contributing to reduced susceptibility towards fluoroquinolones and biocides, but little is known about its variability within S. aureus or its distribution and conservation among other staphylococci. We screened for sequences homologous to S. aureus norA and found it in 61 out of the 63 Staphylococcus species described. To the best of our knowledge, this is the first study to report the occurrence of norA across the Staphylococcus genus. The norA phylogenetic tree follows the evolutionary relations of staphylococci and the closely related Mammalliicoccus genus. Comparative analyses suggest a conservation of the NorA function in staphylococci. We also analyzed the variability of norA within S. aureus, for which there are several circulating norA alleles, differing up to 10% at the nucleotide level, which may hamper proper norA detection. We demonstrate the applicability of a PCR-based algorithm to detect and differentiate norA alleles in 52 S. aureus representing a wider collection of 89 isolates from different hosts. Our results highlight the prevalence of norAI and norAII in different settings and the association of norA alleles with specific S. aureus clonal lineages. Ultimately, it confirms the applicability of our PCR-based algorithm to rapidly detect and assign the different norA alleles, a trait that may impact antimicrobial efflux capacity and the search for potential NorA inhibitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • NorA is a major drug efflux pump, contributes to drug resistance in MRSA. • The study identified potential NorA inhibitors from Traditional Chinese Medicines (TCM). • Three TCM compounds − piperine, demethoxycurcumin, and tectorigenin − showed promising interactions with NorA. • Analysis of RMSD, RMSF, Rg, free energy, and binding pockets confirmed the inhibitory potential of Three TCM. • Ligand-complexed NorA displayed altered motion patterns compared to the apo state particularly at key pocket binding residues. Drug resistance Staphylococcus aureus (S. aureus) is emerging as the most prevalent pathogen in surgical wounds and orthopedic surgeries. NorA is a major drug efflux involved in the drug resistance, reducing intracellular drug concentrations. The current study aimed to find some potential inhibitors derived from Traditional Chinese Medicines (TCM) against NorA using a 500 ns molecular dynamics (MD) simulation. Root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (Rg), free energy, dynamic cross correlation matrix (DCCM) was computed. Three TCM compound; piperine, demethoxycurcumin, and tectorigenin exhibited many hydrogen bonds and hydrophobic contacts in the binding pockets residues, especially with ionizable residues (Arg 98, Glu 222, Asp 307, and Arg 310), forming two different charged regions. RMSD of NorA-piperine complex shows some initial instability at 5.2 Å, followed by an increase to 5.8 Å at 222 ns, and a further rise to 6.1 Å by the end of the 500 ns simulation period. Similarly, the NorA-demethoxycurcumin and NorA-tectorigenin complexes display elevated terminal RMSD of 7.9 Å each. RMSF, Rg, free energy, and binding pockets interactions confirmed the potential activity of piperine, demethoxycurcumin, and tectorigenin against NorA inhibition. In apo state NorA exhibited dispersion within the ranges of −100 to 150 (PC1: 39.97 %) while in complexed with ligands it illustrated significant differences in the motion patterns on PC1 (46.04 % and 27.39 %). The NorA-ligands DCCM displayed predominantly negatively correlated motions, particularly at the terminal resides from 200 to 370 where the pocket binding residues are located. These compounds also demonstrated drug-likeness and fitting best in the binding pocket residues (Asn > 137, Phe > 140, Phe > 303 Asp > 307, Arg > 310, Glu > 222, and Thr > 223). In conclusion, the compounds piperine, demethoxycurcumin, and tectorigenin interact with NorA through hydrogen bonds and hydrophobic contacts, particularly with key ionizable residues, Arg 98, Glu 222, Asp 307, and Arg 310, indicating potential inhibitory activity. [ABSTRACT FROM AUTHOR]

The misuse of antibiotics has led to an alarming increase in bacterial strains resistant to these drugs. Efflux pumps, which expel antibiotics from bacterial cells, have emerged as one of the key mechanisms of bacterial resistance. In the quest to combat and mitigate bacterial resistance, researchers have turned their attention to efflux pump inhibitors as a potential solution. Meldrum's acid, a synthetic molecule widely utilized in the synthesis of bioactive compounds, has garnered significant interest in this regard. Hence, this study aims to investigate the antibacterial activity and evaluate the efficacy of three derivatives of meldrum's acid in inhibiting efflux mechanisms, employing both in silico and in vitro approaches. The antibacterial activity of the derivatives was assessed through rigorous broth microdilution testing. While the derivatives themselves did not exhibit direct antibacterial activity, they demonstrated remarkable potential in potentiating the effects of antibiotics. Additionally, fluorescence emission assays using ethidium bromide (EtBr) revealed fluorescence levels comparable to the positive control, indicating a possible blockade of efflux pumps. Molecular docking studies conducted in silico further supported these findings by revealing binding interactions similar to norfloxacin and CCCP, known efflux pump inhibitors. These results underscore the potential of meldrum's acid derivatives as effective inhibitors of efflux pumps. By inhibiting these mechanisms, the derivatives hold promise in enhancing the effectiveness of antibiotics and combatting bacterial resistance. This study contributes valuable insights into the development of novel strategies to address the pressing issue of bacterial resistance and paves the way for further research and exploration in this field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financialinterestsor personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this work, a protocol of a partially invasive sampling for the archaeometric characterization of ancient mortars from the little Roman Bath of Nora (Sardinia, Italy) is presented. Optical microscopy and different analytical techniques such as X-ray diffraction, X-ray fluorescence, thermo-gravimetric analysis, and physical/mechanical tests have been carried out on the mortars. These analyses were performed to investigate the chemical composition, alteration products, and binder pozzolanic activity. An innovative method of image analysis has been tested to obtain information about the size and shape of both the mortar aggregates and the binder/aggregate ratio. This new particle-size analysis has two different advantages: (i) it saves a huge volume of material compared to a classic granulometric classification through its use of a sieve and (ii) is eco-friendly in respect to the environment by saving a large volume of liquid waste derived from the acid attack for the separation of the insoluble aggregate from the soluble binder, as would be done for a common sieving. Results show a local provenance of the aggregates. The use of two different limestones for the mortars’ binder production was detected and probably this raw material belongs to the nearby Roman town of Karales (current day Cagliari).

Staphylococcus aureus can exhibit resistance to various antibiotics. Among its resistance mechanisms, the active efflux of antibiotics can be seen as relevant. This study aimed to evaluate the ability of resveratrol to modulate norfloxacin resistance in S. aureus. The antimicrobial activity of resveratrol was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC). Then, the modulatory effect of resveratrol was evaluated using the MIC determination for the antibiotic or ethidium bromide in the presence and absence of resveratrol at a sub-MIC level. The MIC of norfloxacin against S. aureus SA1199B (NorA-overexpressing strain) decreased 16-fold when in the presence of resveratrol, with a similar behavior being observed for ethidium bromide. An evaluation of the ethidium bromide accumulation was also performed, showing that in the presence of resveratrol, the SA1199B strain had augmented fluorescence due to the accumulation of ethidium bromide. Altogether, the results suggested that resveratrol may act by inhibiting NorA. These in vitro data were supported by docking results, with interactions between resveratrol and the NorA efflux pump predicted to be favorable. Our findings demonstrated that resveratrol may modulate norfloxacin resistance through the inhibition of NorA, increasing the effectiveness of this antibiotic against S. aureus.

This research paper endeavours to provide a combined and intertextual analysis of the lives and principal works of two of the most important writers of the Victorian era, John Stuart Mill and Henrik Ibsen. The two men have largely influenced the modern outlook towards feminism and the representation of women in literature as well as the real world. Mill's 'The Subjection of Women' is hailed as an exemplary text in the formulation of the tenets of liberal feminism. In the same way, Ibsen's play, 'A Doll's House', is often thought to be revolutionary for being the first in its representation of a feminist woman on stage. This paper attempts to study Ibsen's play using the feminist framework provided by Mill. In doing so, it seeks to highlight and inspire men aligned toward equality for women. [ABSTRACT FROM AUTHOR]

One promising approach in treating antibiotic-resistant bacteria is to “break” resistances connected with antibacterial efflux by co-administering efflux pump inhibitors (EPIs) with antibiotics. Here, ten compounds, previously optimized to restore the susceptibility to ciprofloxacin (CIP) of norA-overexpressing Staphylococcus aureus, were evaluated for their ability to inhibit norA-mediated efflux in Staphylococcus pseudintermedius and synergize with CIP, ethidium bromide (EtBr), gentamycin (GEN), and chlorhexidine digluconate (CHX). We focused efforts on S. pseudintermedius as a pathogenic bacterium of concern within veterinary and human medicine. By combining data from checkerboard assays and EtBr efflux inhibition experiments, the hits 2-arylquinoline 1, dihydropyridine 6, and 2-phenyl-4-carboxy-quinoline 8 were considered the best EPIs for S. pseudintermedius. Overall, most of the compounds, except for 2-arylquinoline compound 2, were able to fully restore the susceptibility of S. pseudintermedius to CIP and synergize with GEN as well, while the synergistic effect with CHX was less significant and often did not show a dose-dependent effect. These are valuable data for medicinal chemistry optimization of EPIs for S. pseudintermedius and lay the foundation for further studies on successful EPIs to treat staphylococcal infections.

The expression of the efflux pump systems is the most important mechanism of antibiotic resistance in bacteria, as it contributes to reduced concentration and the subsequent inactivity of administered antibiotics. NorA is one of the most studied antibacterial targets used as a model for efflux-mediated resistance. The present study evaluated shikimate pathway-derived phenolic acids against NorA (PDB ID: 1PW4) as a druggable target in antibacterial therapy using in silico modelling and in vitro methods. Of the 22 compounds evaluated, sinapic acid (−9.0 kcal/mol) and p-coumaric acid (−6.3 kcal/mol) had the best and most prominent affinity for NorA relative to ciprofloxacin, a reference standard (−4.9 kcal/mol). A further probe into the structural stability and flexibility of the resulting NorA-phenolic acids complexes through molecular dynamic simulations over a 100 ns period revealed p-coumaric acid as the best inhibitor of NorA relative to the reference standard. In addition, both phenolic acids formed H-bonds with TYR 76, a crucial residue implicated in NorA efflux pump inhibition. Furthermore, the phenolic acids demonstrated favourable drug likeliness and conformed to Lipinski's rule of five for ADME properties. For the in vitro evaluation, the phenolic acids had MIC values in the range 31.2 to 62.5 μg/mL against S. aureus, and E. coli, and there was an overall reduction in MIC following their combination with ciprofloxacin. Taken together, the findings from both the in silico and in vitro evaluations in this study have demonstrated high affinity of p-coumaric acid towards NorA and could be suggestive of its exploration as a novel NorA efflux pump inhibitor. [ABSTRACT FROM AUTHOR]

Building an efficient facility for advanced bronchoscopic procedures involves many considerations. This review places particular emphasis on anesthesiology services, based on experience at a tertiary/quaternary care referral academic medical center. Topics include equipment requirements, applicable clinical standards, and multidisciplinary collaboration. Patient flow arrangements for both outpatients and inpatients, from preoperative care to discharge/disposition, are highlighted. The importance of effective business planning, personnel training, leadership, communication, team building, quality of care, and patient safety are also discussed. [ABSTRACT FROM AUTHOR]

Background: Chlorhexidine is one of the most essential ingredients in infection control applications. Except qacA, the effects of other various efflux-medicated biocide genes (including qacB, qacC, qacEΔ1, qacH or norA) on biguanides resistance are still controversial. In addition, most of the studies have discussed the effect of qacA/B on clinical S. aureus isolates but not that qacA or qacB individually. Methods: In total, 254 methicillin-resistant Staphylococcus aureus (MRSA), selected 30 methicillin-susceptible S. aureus (MSSA) clinical isolates from different patients during 2014–2015 and 15 S. aureus quality control strains (including Mu3 and Mu50) were included in the study. Various biocide genes, including qacA/B, qacC, qacH, qacEΔ1, and different types of norA, were determined through conventional PCR. S. aureus isolates with qacA/B (+) were analyzed using high-resolution melting curve (HRM) to differentiate qacA from qacB. The chlorhexidine MIC was determined using the agar dilution method. Univariate and multivariate statistics were analyzed to see which biocide resistant genes had effects on chlorhexidine MIC. Results: Results of all HRM analyses (n = 22) were consistent with those of Sanger sequencing for differentiation of qacA from qacB. None of the isolates harbored qacH and only one MRSA harbored qacEΔ1. The harboring rate of qacA, qacB, and qacC among MRSA/MSSA isolates was 7.1% (n = 18)/0%, 38.2% (n = 97)/0%, and 7.5% (n = 19)/3.3% (n = 1), respectively. The most type of norA was norAI (n = 158), followed by norAIII (n = 87) and norAII (n = 9) among MRSA isolates. Based on the results of multivariate logistic regression analyses, only qacA and qacB would increase chlorhexidine MIC from ≤ 1 ug/ml to ≥ 2 ug/ml in MRSA isolates (P < 0.001) but not qacC or norA types (P=0.976 and 0.633 or 0.933, respectively). In addition, only qacA but not qacB was contributed to elevate chlorhexidine from ≤ 1 ug/ml to 4 ug/ml in MRSA isolates (P < 0.001 and 0.017, respectively). Conclusion: HRM analysis can be a great method to differentiate qacA from qacB. The biocide gene with the most effect on chlorhexidine MIC in S. aureus isolates was qacA, followed by qacB, but qacC and different types of norA did not have any effect on chlorhexidine susceptibility. Further investigation on the influence of qacB, qacC and types of norA on chlorhexidine susceptibility is necessary.

Background: Activity of norA efflux pump is one of the antibiotic resistance mechanisms in ciprofloxacin resistant Staphylococcus aureus. In this study, the effect of Artemisia ciniformis extract on reducing the expression of norA efflux pumps gene in ciprofloxacin-resistant Staphylococcus aureus isolates was studied. Materials and Methods: Ciprofloxacin resistant S. aureus isolates, were treated by different concentration of A. ciniformis extract. After extracting RNA and synthesizing cDNA, norA efflux pump expression was evaluated by Real Time PCR. Results: There was significant decrease of norA efflux pump expression in ciprofloxacin-resistant S. aureus isolates treated by A. ciniformis extract (P

NorA is the most studied efflux pump of Staphylococcus aureus and is responsible for high level resistance towards fluoroquinolone drugs. Although along the years many NorA efflux pump inhibitors (EPIs) have been reported, poor information is available about structure-activity relationship (SAR) around their nuclei and reliability of data supported by robust assays proving NorA inhibition. In this regard, we focussed efforts on the 2-phenylquinoline as a promising chemotype to develop potent NorA EPIs. Herein, we report SAR studies about the introduction of different aryl moieties on the quinoline C-2 position. The new derivative 37a showed an improved EPI activity (16-fold) with respect to the starting hit 1. Moreover, compound 37a exhibited a high potential in time-kill curves when combined with ciprofloxacin against SA-1199B (norA+). Also, 37a exhibited poor non-specific effect on bacterial membrane polarisation and showed an improvement in terms of “selectivity index” in comparison to 1.

Abstract Background Children require anesthesia for MRI to maintain immobility and reduce discomfort; clear indications about the best anesthesiologic management are lacking and each center developed its own protocol. Moreover, children with neuropsychiatric disorders more likely require sedation and are described in literature as more prone to general and respiratory complications. Aim of this study was to analyze the applicability of a sevoflurane-based approach, to describe general and respiratory complications and to identify risk factors in a pediatric neuropsychiatric population. Methods Retrospective cohort study, university Hospital (January 2007–December 2016). All the 1469 anesthesiologic records of children addressed from Neuropsychiatric Unit to undergo MRI under general anesthesia were analyzed; 12 patients equal or older than 18-year-old were excluded. We identified post-hoc nine macro-categories: static encephalopathies, metabolic/evolutive encephalopathies, epileptic encephalopathies, neuromuscular diseases, autistic spectrum disorders, migraine, psychiatric disorders, intellectual disabilities, others. A logistic regression model for events with low frequency (Firth’s penalized likelihood approach) was carried out to identify the mutually adjusted effect among endpoints (complications) and the independent variables chosen on the basis of statistical significance (univariate analysis, p ≤ 0.05) and clinical judgment. Results Of 1457 anesthesiologic records (age 4.0 (IQR 2.0 to 7.0) year-old, males 891 (61.2%), weight 17.0 (IQR 12.0 to 24.9) kg), 18 were cancelled for high anesthesiologic risk, 50 were cooperative, 1389 were anesthetized. A sevoflurane-based anesthesia was feasible in 92.3%; these patients required significantly less mechanical ventilation (8.6 vs. 16.2%; p = 0.012). Complications’ rate was low (6.2%; 3.1% respiratory). The risk for general complications increases with ASA score > 1 (OR 2.22, 95 CI% 1.30 to 3.77, p = 0.003), male sex (OR 1.73, 95% CI 1.07 to 2.81, p = 0.025), multi-drug anesthesia (OR 2.98, 95 CI% 1.26 to 7.06, p = 0.013). For respiratory complications, it increases with ASA score > 1 (OR 2.34, 95 CI% 1.19 to 4.73, p = 0.017), autumn-winter (OR 2.01, 95 CI% 1.06 to 3.78, p = 0.030), neuromuscular disorders (OR 3.18, 95 CI% 1.20 to 8.41, p = 0.020). We had no major complications compromising patients’ outcome or requiring admission to ICU. Conclusions Sevoflurane anesthesia is feasible and safe for children affected by neuropsychiatric disorders undergoing MRI. Specific risk factors for general and respiratory complications should be considered.

NorA is one of the main native MDR efflux pumps of Staphylococcus aureus, contributing to reduced susceptibility towards fluoroquinolones and biocides, but little is known about its variability within S. aureus or its distribution and conservation among other staphylococci. We screened for sequences homologous to S. aureus norA and found it in 61 out of the 63 Staphylococcus species described. To the best of our knowledge, this is the first study to report the occurrence of norA across the Staphylococcus genus. The norA phylogenetic tree follows the evolutionary relations of staphylococci and the closely related Mammalliicoccus genus. Comparative analyses suggest a conservation of the NorA function in staphylococci. We also analyzed the variability of norA within S. aureus, for which there are several circulating norA alleles, differing up to 10% at the nucleotide level, which may hamper proper norA detection. We demonstrate the applicability of a PCR-based algorithm to detect and differentiate norA alleles in 52 S. aureus representing a wider collection of 89 isolates from different hosts. Our results highlight the prevalence of norAI and norAII in different settings and the association of norA alleles with specific S. aureus clonal lineages. Ultimately, it confirms the applicability of our PCR-based algorithm to rapidly detect and assign the different norA alleles, a trait that may impact antimicrobial efflux capacity and the search for potential NorA inhibitors.

In this work, a protocol of a partially invasive sampling for the archaeometric characterization of ancient mortars from the little Roman Bath of Nora (Sardinia, Italy) is presented. Optical microscopy and different analytical techniques such as X-ray diffraction, X-ray fluorescence, thermogravimetric analysis, and physical/mechanical tests have been carried out on the mortars. These analyses were performed to investigate the chemical composition, alteration products, and binder pozzolanic activity. An innovative method of image analysis has been tested to obtain information about the size and shape of both the mortar aggregates and the binder/aggregate ratio. This new particle-size analysis has two different advantages: (i) it saves a huge volume of material compared to a classic granulometric classification through its use of a sieve and (ii) is eco-friendly in respect to the environment by saving a large volume of liquid waste derived from the acid attack for the separation of the insoluble aggregate from the soluble binder, as would be done for a common sieving. Results show a local provenance of the aggregates. The use of two different limestones for the mortars' binder production was detected and probably this raw material belongs to the nearby Roman town of Karales (current day Cagliari). [ABSTRACT FROM AUTHOR]

Efflux pumps are one of the predominant microbial resistant mechanisms leading to the development of multidrug resistance. In Staphylococcus aureus , overexpression of NorA protein enables the efflux of antibiotics belonging to the class of fluoroquinolones and, thus, makes S. aureus resistant. Hence, NorA efflux pumps are being extensively exploited as the potential drug target to evade bacterial resistance and resensitize bacteria to the existing antibiotics. Although several molecules are reported to inhibit NorA efflux pump effectively, boronic acid derivatives were shown to have promising NorA efflux pump inhibition. In this regard, the current study exploits 6-(3-phenylpropoxy)pyridine-3-boronic acid to further improve the activity and reduce cytotoxicity using the bioisostere approach, a classical medicinal chemistry concept. Using the SWISS-Bioisostere online tool, from the parent compound, 42 compounds were obtained upon the replacement of the boronic acid. The 42 compounds were docked with modeled NorA protein, and key molecular interactions of the prominent compounds were assessed. The top hit compounds were further analyzed for their drug-like properties using ADMET studies. The identified potent lead, 5-nitro-2-(3-phenylpropoxy)pyridine (5-NPPP), was synthesized, and in vitro efficacy studies have been proven to show enhanced efflux inhibition, thus acting as a potent antibiotic breaker to resensitize S. aureus without elucidating any cytotoxic effect to the host Hep-G2 cell lines. [ABSTRACT FROM AUTHOR]

Undue exposure to antimicrobials has led to the acquisition and development of sophisticated bacterial resistance mechanisms, such as efflux pumps, which are able to expel or reduce the intracellular concentration of various antibiotics, making them ineffective. Therefore, inhibiting this mechanism is a promising way to minimize the phenomenon of resistance in bacteria. In this sense, the present study sought to evaluate the activity of the Carvacrol (CAR) and Thymol (THY) terpenes as possible Efflux Pump Inhibitors (EPIs), by determining the Minimum Inhibitory Concentration (MIC) and the association of these compounds in subinhibitory concentrations with the antibiotic Norfloxacin and with Ethidium Bromide (EtBr) against strains SA-1199 (wild-type) and SA-1199B (overexpresses NorA) of Staphylococcus aureus. In order to verify the interaction of the terpenes with the NorA efflux protein, an in silico molecular modeling study was carried out. The assays used to obtain the MIC of CAR and THY were performed by broth microdilution, while the Efflux Pump inhibitory test was performed by the MIC modification method of the antibiotic Norfloxacin and EtBr. docking was performed using the Molegro Virtual Docker (MVD) program. The results of the study revealed that CAR and THY have moderate bacterial activity and are capable of reducing the MIC of Norfloxacin antibiotic and EtBr in strains of S. aureus carrying the NorA efflux pump. The docking results showed that these terpenes act as possible competitive NorA inhibitors and can be investigated as adjuvants in combined therapies aimed at reducing antibiotic resistance. [ABSTRACT FROM AUTHOR]

Background: Uncooperative children require sedative approach for dental treatment. The aim was to assess the effectiveness of Propofol in "Non-Operating Room Anesthesia" (NORA) for paediatric dental treatment; intraoperative side effects; postoperative side effects; post-discharge effects. Methods: a prospective study, involving 109 uncooperative children undergoing sedation in NORA using Propofol for dental treatment, was performed. Working sessions, success/failure, intraoperative and postoperative side effects, number of treatment; type of procedure were assessed. Parents completed a post-discharge questionnaire on: pain; crying; fever; vomiting; headache; drowsiness; excitability; irritability; ability to eat; drugs and medical care needing. Results: Success: 96.7%. Intraoperative side effects: 33.3%. Postoperative side effects: 6.4%. Statistically significant association between: intraoperative side effects and age (p = 0.001), health status (p = 0.0007), weight (p = 0.038), respectively; intraoperative side effects and number/type of dental treatment (p = 0.0055) and scaling (p = 0.0001), respectively. For post-discharge questionnaires, statistically significant association between: age and crying (p = 0.0001) and headache (p = 0.002), respectively; health status and crying (p = 0.015) and drugs needing (p = 0.04), respectively; weight and crying (p = 0.0004); extraction and pain (p = 0.0001) and crying (p= 0.0073), respectively; scaling and crying (p = 0.04), excitability and irritability (p = 0.03), respectively. Conclusion: Propofol in NORA was effective with minimal side effects. [ABSTRACT FROM AUTHOR]

Recensione

Efflux pumps are one of the predominant microbial resistant mechanisms leading to the development of multidrug resistance. In Staphylococcus aureus, overexpression of NorA protein enables the efflux of antibiotics belonging to the class of fluoroquinolones and, thus, makes S. aureus resistant. Hence, NorA efflux pumps are being extensively exploited as the potential drug target to evade bacterial resistance and resensitize bacteria to the existing antibiotics. Although several molecules are reported to inhibit NorA efflux pump effectively, boronic acid derivatives were shown to have promising NorA efflux pump inhibition. In this regard, the current study exploits 6-(3-phenylpropoxy)pyridine-3-boronic acid to further improve the activity and reduce cytotoxicity using the bioisostere approach, a classical medicinal chemistry concept. Using the SWISS-Bioisostere online tool, from the parent compound, 42 compounds were obtained upon the replacement of the boronic acid. The 42 compounds were docked with modeled NorA protein, and key molecular interactions of the prominent compounds were assessed. The top hit compounds were further analyzed for their drug-like properties using ADMET studies. The identified potent lead, 5-nitro-2-(3-phenylpropoxy)pyridine (5-NPPP), was synthesized, and in vitro efficacy studies have been proven to show enhanced efflux inhibition, thus acting as a potent antibiotic breaker to resensitize S. aureus without elucidating any cytotoxic effect to the host Hep-G2 cell lines.

The ritual space of the Sanctuary of Aesculapius in Nora (Sardinia) is the main focus of a recent archaeological campaign led by the Cultural Heritage Department of the University of Padova. A partnership with 3DOM research group (Fondazione Bruno Kessler, Trento) has offered new opportunities for a digital investigation of the site. The aim of the project is to map and visualize the sanctuary with methodologies enabling different users to engage with the site in new ways. They offer different web tools for exploring, understanding and interacting with the site, by focusing on 3D modelling, semantic enrichment and the contextualization of digital records. The entire site of Nora has been surveyed by a drone, which produced a digital model of the peninsula. A number of outputs have been used for different scales of visualization and a range of purposes: an open source multi-resolution web renderer is used to navigate the point cloud, labelled using a system of bounding boxes. At the same time it provides access to a 2.5D model of each building. Plugins in QGIS are used to produce extrusions of any mapped feature, gaining height values from the point cloud, and attributes from the shapefile. Photogrammetric models of single ritual artifacts can be located in their own context and be displayed using 3D web renderers.

Staphylococci are rapidly resistant to most antibiotics and cause many therapeutic problems. Of these, the efflux pumps are the most important cause of resistance to antibiotics, and these pumps are the core of the inherent inflammatory system of the nor gene. Staphylococcus aureus, norA, norB, and norC are chromosomal genes that encode these pumps, expressing high levels of multi-drug resistance genes can produce resistance to quinolones. The purpose of this study was to investigate the presence of norA B, C genes in the presence of germs in the isolates of Staphylococcus aureus isolated from the samples of urinary tract infection. In this study, samples from 300 urine samples of patients referred to the laboratories in north of Tehran were collected and identified 100 samples of Staphylococcus aureus. After identification of resistant strains of fluoroquinolone family antibiotics, DNA extraction was performed to confirm the presence of norA, norB and nor C genes by PCR reaction. The results were analyzed by electrophoresis on agarose gel. Of the 100 isolated isolates of Staphylococcus aureus, 60 isolates were resistant to the ciprofloxacin disc, 30 isolates were resistant to neurofloxacin and 10 isolates compared to furosemide. Of the 100 isolates, 30 isolates possessed a norB resistance gene, 20 had norC gene and 20 had norA gene. Also, 10 isolates containing all three genes and 15 isolates, had 2 genes from the 3 genes studied.

In 1952, during the excavation of the roman forum of Nora (Sardinia, Italy) leaded by G. Pesce, a marble artefact with an inscription in Punic alphabet was found. This object was not published and today it is missing, but the study of archival documents has allowed to reconstruct its own story: it is a Punic inscribed slab, recycled to make a pelta-shaped oscillum in the Roman age; the roughed artefact was not completed and finally, in the late antiquity, it was stored with other marble fragments, probably destined to a limekiln.

The expression of the efflux pump systems is the most important mechanism of antibiotic resistance in bacteria, as it contributes to reduced concentration and the subsequent inactivity of administered antibiotics. NorA is one of the most studied antibacterial targets used as a model for efflux-mediated resistance. The present study evaluated shikimate pathway-derived phenolic acids against NorA (PDB ID: 1PW4) as a druggable target in antibacterial therapy using in silico modelling and in vitro methods. Of the 22 compounds evaluated, sinapic acid (−9.0 kcal/mol) and p-coumaric acid (−6.3 kcal/mol) had the best and most prominent affinity for NorA relative to ciprofloxacin, a reference standard (−4.9 kcal/mol). A further probe into the structural stability and flexibility of the resulting NorA-phenolic acids complexes through molecular dynamic simulations over a 100 ns period revealed p-coumaric acid as the best inhibitor of NorA relative to the reference standard. In addition, both phenolic acids formed H-bonds with TYR 76, a crucial residue implicated in NorA efflux pump inhibition. Furthermore, the phenolic acids demonstrated favourable drug likeliness and conformed to Lipinski’s rule of five for ADME properties. For the in vitro evaluation, the phenolic acids had MIC values in the range 31.2 to 62.5 μg/mL against S. aureus, and E. coli, and there was an overall reduction in MIC following their combination with ciprofloxacin. Taken together, the findings from both the in silico and in vitro evaluations in this study have demonstrated high affinity of p-coumaric acid towards NorA and could be suggestive of its exploration as a novel NorA efflux pump inhibitor.

Staphylococcus aureus , a gram-positive bacterial pathogen, develops antibiotic resistance partly through enhanced activity of transmembrane multi-drug efflux pump proteins like NorA. Being a prominent member of the Major Facilitator Superfamily (MFS), NorA transports various small molecules including hydrophilic fluoroquinolone antibiotics across the cell membrane. Intriguingly, NorA is inhibited by a structurally diverse set of small molecule inhibitors as well, indicating a highly promiscuous ligand/inhibitor recognition. Our study aims to elucidate the structural facets of this promiscuity. Known NorA inhibitors were grouped into five clusters based on chemical class and docked into ligand binding pockets on NorA conformations generated via molecular dynamics simulations. We discovered that several key residues, such as I23, E222, and F303, are involved in inhibitor binding. Additionally, residues I244, T223, F303, and F140 were identified as prominent in interactions with specific ligand clusters. Our findings suggest that NorA's substrate binding site, encompassing residues aiding ligand recognition based on chemical nature, facilitates the recognition of chemically diverse ligands. This insight into NorA's structural promiscuity in ligand recognition not only enhances understanding of antibiotic resistance mechanisms in S. aureus but also sets the stage for the development of more effective efflux pump inhibitors, vital for combating multidrug resistance.Communicated by Ramaswamy H. Sarma.

Endogenous transporters protect Staphylococcus aureus against antibiotics and also contribute to bacterial defense from environmental toxins. We evaluated the effect of overexpression of four efflux pumps, NorA, NorB, NorC, and Tet38, on S. aureus survival following exposure to pyocyanin (PYO) of Pseudomonas aeruginosa , using a well diffusion assay. We measured the PYO-created inhibition zone and found that only an overexpression of NorA reduced S. aureus susceptibility to pyocyanin killing. The MIC PYO of the NorA overexpressor increased threefold compared to that of wild-type RN6390 and was reduced 2.5-fold with reserpine, suggesting that increased NorA efflux caused PYO resistance. The PYO-created inhibition zone of a ΔnorA mutant was consistently larger than that of a plasmid-borne NorA overexpressor. PYO also produced a modest increase in norA expression (1.8-fold at 0.25 µg/mL PYO) that gradually decreased with increasing PYO concentrations. Well diffusion assays carried out using P. aeruginosa showed that ΔnorA mutant was less susceptible to killing by PYO-deficient mutants PA14 phzM and PA14 phzS than to killing by PA14. NorA overexpression led to reduced killing by all tested P. aeruginosa . We evaluated the NorA-PYO interaction using a collection of 22 clinical isolates from adult and pediatric cystic fibrosis (CF) patients, which included both S. aureus (CF-SA) and P. aeruginosa (CF-PA). We found that when isolated alone, CF-PA and CF-SA expressed varying levels of PYO and norA transcripts, but all four CF-PA/CF-SA pairs isolated concurrently from CF patients produced a low level of PYO and low norA transcript levels, respectively, suggesting a partial adaptation of the two bacteria in circumstances of persistent co-colonization., Competing Interests: The authors declare no conflict of interest.

NorA is the most studied efflux pump of Staphylococcus aureus and is responsible for high level resistance towards fluoroquinolone drugs. Although along the years many NorA efflux pump inhibitors (EPIs) have been reported, poor information is available about structure-activity relationship (SAR) around their nuclei and reliability of data supported by robust assays proving NorA inhibition. In this regard, we focussed efforts on the 2-phenylquinoline as a promising chemotype to develop potent NorA EPIs. Herein, we report SAR studies about the introduction of different aryl moieties on the quinoline C-2 position. The new derivative 37a showed an improved EPI activity (16-fold) with respect to the starting hit 1. Moreover, compound 37a exhibited a high potential in time-kill curves when combined with ciprofloxacin against SA-1199B (norA+). Also, 37a exhibited poor non-specific effect on bacterial membrane polarisation and showed an improvement in terms of "selectivity index" in comparison to 1. [ABSTRACT FROM AUTHOR]

Increasing drug resistance among Staphylococcus aureus is a global health threat and finding alternative antimicrobial agents against it has been considered. Multidrug resistance efflux pumps, including NorA, are involved with resistance to different drugs, especially fluoroquinolones, in S. aureus. Using metal nanoparticles against pathogenic bacteria is a promising approach; however, physio-chemical synthesis of nanoparticles has limitations. Biosynthesis of metal nanoparticles with antibacterial activity has gained interest, recently. In this study, biosynthesis of CuFe2O4@Ag nanocomposite using aqueous extract from microalgae Chlorella vulgaris was performed, and its antibacterial property and effect on expression of norA efflux pump gene were investigated. Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive X-ray mapping analysis (EDX-map), differential reflectance spectroscopy (DRS), and dynamic light scattering (DLS) were used to characterize synthesized nanocomposite. Antibacterial activity of the prepared nanocomposite individually and combined with ciprofloxacin against S. aureus strains was evaluated using the disk assay method, and minimum inhibitory concentration (MIC) of each agent was determined using the broth dilution method. Anti-biofilm activity of this nanocomposite was checked. Finally, the effect of CuFe2O4@Ag nanocomposite alone and in combination with ciprofloxacin on the expression of norA was assessed by real-time PCR. The physical analysis revealed proper synthesis of spherical and well-dispersed CuFe2O4@Ag nanocomposite with an average diameter of 20 nm. Synthesized nanocomposite had synergistic antibacterial activity with ciprofloxacin. Moreover, expression of norA gene among clinical and standard strains treated with CuFe2O4@Ag nanocomposite combined with ciprofloxacin reduced by 59% and 65%, respectively. Thus, CuFe2O4@Ag nanocomposite synthesized in this study can be considered as a promising candidate to be used to inhibit staphylococcal efflux pump genes and increasing the antibiotic efficacy. [ABSTRACT FROM AUTHOR]