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The ability of Pseudomonas aeruginosa to colonize medical devices and human tissues while growing in resistant communities called biofilms is a worldwide public health concern. P. aeruginosa biofilms have increased antibiotic tolerance and are more resistant to host responses than their planktonic counterparts, which makes the clearance of these biofilms difficult and infections chronic. A critical clinical trait of P. aeruginosa is its capacity to interact and coexist with other microorganisms in multispecies communities. From a clinical point of view, these interactions are usually detrimental to the patient, as infections caused by multiple species are often associated with worse prognosis. On the other hand, from a biotechnological perspective, there is a challenge to recreate the optimal conditions to grow multiple bacterial species simultaneously. P. aeruginosa can interact with other bacteria, fungi and viruses and together infect a wide range of human tissues.This study focuses on the main traits of P. aeruginosa biofilms, placing particular emphasis on the clinical challenges they represent in terms of antimicrobial susceptibility and biofilm infection clearance. Furthermore, it also highlights the main microbial interactions of Pseudomonas and the current models used to recreate them under laboratory conditions. The antimicrobial and antibiofilm strategies developed against P. aeruginosa mono and multispecies biofilms are also detailed. ; The group is supported by the Ministerio de Economía, Industria y Competitividad, MINECO, and Agencia Estatal de Investigación (AEI), Spain, co-funded by Fondo Europeo de Desarrollo Regional, FEDER, European Union (RTI2018-098573-B- 100), the CERCA programme and AGAUR-Generalitat de Catalunya (2017SGR-1079), the European Regional Development Fund (FEDER), Catalan Cystic Fibrosis association and Obra Social "La Caixa" ; Postprint (published version)

The rapid emergence of infections caused by multidrug-resistant Pseudomonas aeruginosa is becoming one of the most important concerns in the medical sector. Due to the failure of current antibiotic regimes in addressing this problem, the use of bacteriophages as potential pharmaceuticals has gained special attention in the past decade. This review offers a brief introduction to the complications associated to antibiotic-resistant P. aeruginosa and the advantages that phage therapy might offer in the matter. Then, it collects and discusses the most recent literature of this therapeutic approach in the context of P. aeruginosa, making a distinction among its three main categories: monophage, polyphage and phage-antibiotic complementation therapy. Finally, it examines the way in which the current legislation hinders research and investment on bacteriophages, and explains the reason why a new regulatory framework is needed for phage therapy.

Background: Pseudomonas aeruginosa is an opportunistic pathogen which causes most of the chronic infection in humans. This study was undertaken to determine the prevalence rate of Pseudomonas aeruginosa that is isolated from various clinical specimens along with its antibiotic susceptibility pattern.Methods: This descriptive cross sectional study was conducted in Kathmandu Medical College and Teaching Hospital (KMCTH) from February to May 2018. Pseudomonas aeruginosa isolated from various clinical specimens were processed in clinical laboratory, Department of Microbiology, KMCTH. Isolation, identification and sensitivity of Pseudomonas aeruginosa to antibiotics were measured.Results: A total of 7527 samples were been processed of which 46 isolates of Pseudomonas aeruginosa were obtained. Pseudomonas aeruginosa was isolated mainly from Pus, Wound swab, Sputum and Tracheal aspirate. Here 63.04% Pseudomonas aeruginosa isolates were resistant to Ceftazidime, 65.21% to Cefixime, 56.52% to Ceftriaxone and Cefotaxime followed by 56.52% to Piperacillin. Furthermore, the current study reveals antibiotics like Imipenem, Meropenem, Piperacillin/Tazobactam, Ciprofloxacin, Gentamicin, Amikacin and Tobramycin were found to be good choice for the treatment of infection caused by this organism.Conclusions: Continuous monitoring of antibiotic susceptibility pattern of Pseudomonas aeruginosa is essential and rational treatment regimens prescription by the clinicians is required to limit the spread of antimicrobial resistance.Keywords: Antibiotic resistance; clinical isolates; Pseudomonas aeruginosa.

Inorganic phosphate (Pi) is a central signaling molecule that modulates virulence in various pathogens. In Pseudomonas aeruginosa, low Pi concentrations induce transcriptional alterations that increase virulence. Also, under low Pi levels, P. aeruginosa exhibits Pi chemotaxis—a process mediated by the two non-paralogous receptors CtpH and CtpL. Here we show that the two receptors operate via different mechanisms. We demonstrate that the ligand binding domain (LBD) of CtpH but not CtpL binds Pi directly. We identify the periplasmic ligand binding protein PstS as the protein that binds in its Pi loaded state to CtpL, resulting in receptor stimulation. PstS forms part of the Pi transporter and has thus a double function in Pi transport and chemotaxis. The affinity of Pi for CtpH was modest whereas that for PstS very high, which may explain why CtpH and CtpL mediate chemotaxis to high and low Pi concentrations, respectively. The pstS/ctpH double mutant was almost devoid of Pi taxis, indicating that PstS is the only CtpL Pi-shuttle. Chemotaxis mechanisms based on indirect ligand recognition were unambiguously identified in enterobacteria. The discovery of a similar mechanism in a different bacterial order, involving a different chemoreceptor type and chemoeffector suggests that such systems are widespread. [EN] ; We acknowledge financial support from FEDER funds and Fondo Social Europeo through grants from the Junta de Andalucía (grant CVI-7335 to T.K.) and the Spanish Ministry for Economy and Competitiveness (grants BIO2013-42297 to T.K.). Work at the University of Murcia was funded by grant CTQ-2012-33717 from Ministerio de Economía y Competitividad, co-financed by the European Union (FEDER), a grant from Grupos de Excelencia de la Region de Murcia 04531/GERM/06, and a FPI-MICINN fellowship to A.I.D. A.O. acknowledges a CSIC JAE-Doc contract co-funded by the European Social Fund. ; Peer reviewed

Pseudomonas aeruginosa is ubiquitously present in the environment and acts as an opportunistic pathogen on humans, animals and plants. We report here the effects of the prebiotic polysaccharide inulin and its hydrolysed form FOS on this bacterium. FOS was found to inhibit bacterial growth of strain PAO1, while inulin did not affect growth rate or yield in a significant manner. Inulin stimulated biofilm formation, whereas a dramatic reduction of the biofilm formation was observed in the presence of FOS. Similar opposing effects were observed for bacterial motility, where FOS inhibited the swarming and twitching behaviour whereas inulin caused its stimulation. In co-cultures with eukaryotic cells (macrophages) FOS and, to a lesser extent, inulin reduced the secretion of the inflammatory cytokines IL-6, IL-10 and TNF- a . Western blot experiments indicated that the effects mediated by FOS in macrophages are associated with a decreased activation of the NF- k B pathway. Since FOS and inulin stimulate pathway activation in the absence of bacteria, the FOS mediated effect is likely to be of indirect nature, such as via a reduction of bacterial virulence. Further, this modulatory effect is observed also with the highly virulent ptxS mutated strain. Co-culture experiments of P. aeruginosa with IEC18 eukaryotic cells showed that FOS reduces the concentration of the major virulence factor, exotoxin A, suggesting that this is a possible mechanism for the reduction of pathogenicity. The potential of these compounds as components of antibacterial and anti-inflammatory cocktails is discussed. ; The authors acknowledge financial support from FEDER funds and Fondo Social Europeo through grants from the Spanish Ministry of Economy and Competitiveness (grants SAF2011-22922, SAF2011-22812) the Andalusian regional government Junta de Andalucía (grant CVI-7335) and the Centre of Networked Biomedical Research on Hepatic and Digestive Diseases (CIBERehd) which is funded by the Carlos III Health Institute and the Ramón Areces ...

Anca Chiriac,1–3 Piotr Brzezinski,4 Liliana Foia,5 Iosif Marincu61Apollonia University, 2Nicolina Medical Center, Department of Dermatology, 3"P.Poni" Institute of Macromolecular Chemistry, Iasi, Romania; 4Department of Dermatology, 6th Military Support Unit, Ustka, Poland; 5Grigore T. Popa University of Medicine and Pharmacy, Iasi, Romania; 6Victor Babes University of Medicine and Pharmacy, Timisoara, RomaniaAbstract: Green nails, also known as chloronychia or green nail syndrome, are characterized by green discoloration of the nail plate (greenish-yellow, greenish-brown, greenish-black), proximal chronic non-tender paronychia, and distolateral onycholysis. The cause is Pseudomonas aeruginosa infection of the nail plate in persons whose hands are constantly exposed to water, soaps, and detergents or are subject to mechanical trauma, especially in the elderly. Green or black coloration of the nails should raise suspicion for Pseudomonas infection and be treated with an oral quinolone (ciprofloxacin), particularly in aged patients. We present three cases of green nails in elderly persons.Keywords: chloronychia, green nail syndrome, Pseudomonas aeruginosa, elderly

Pseudomonas aeruginosa is an opportunistic pathogen that causes a number of infections in immunocompromised patients. This organism appears to improve resistance to many antimicrobial agents and a high percentage of clinical isolates of P. aeruginosa exhibit multidrug resistance (MDR) phenotype . The purpose of this study is to screen the antibiotic susceptibility patterns and the prevalence of qacE delta1 gene among bacterial isolates. Accordingly, 145 samples were collected from different clinical sources from patients who admitted to different hospitals in Baghdad city in a period ranged 23/8/2018-1/1/2019. The isolates were diagnosed as P. aeruginosa based on routine bacteriological methods and confirmed by a molecular method using 16SrRNA gene. The antibiotic susceptibility test was performed to all identified isolates by Kirby-Bauer Disk Diffusion method using ten types of antibiotics. The results of antibiotics susceptibility test revealed high levels of resistance toward Piperacillin (72.22%), Trimethoprim (68%), Ceftazidime (68%), Colistin (40.28%), and Levofloxacin (33.33%). And , the minimum inhibitory concentration (MIC) of Cetrimide was tested using different concentrations (2.048 to 0.004µg/100µl) and the results showed that MIC values ranged between 2.048 and 0.016) μg/100μL, and the concentration of 0.256 μg/100μl was more frequent . Finally, the prevalence of qacE delta1 gene among bacterial isolates was detected in percentage 63.88% among bacterial isolates .

Quorum sensing plays a pivotal role in Pseudomonas aeruginosas virulence. This paper reviews experimental results on antimicrobial strategies based on quorum sensing inhibition and discusses current targets in the regulatory network that determines P. aeruginosa biofilm formation and virulence. A bioinformatics framework combining literature mining with information from biomedical ontologies and curated databases was used to create a knowledge network of potential anti-quorum sensing agents for P. aeruginosa. A total of 110 scientific articles, corresponding to 1,004 annotations were so far included in the network and are analysed in this work. Information on the most studied agents, QS targets and methods is detailed. This knowledge network offers a unique view of existing strategies for quorum sensing inhibition and their main regulatory targets and may be used to readily access otherwise scattered information and to help generate new testable hypotheses. This knowledge network is publicly available at http://pcquorum.org/ ; This work was partially funded by the Research Grant 2014 of Anália Lourenço by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), the INOU16-05 project from the Provincial Council of Ourense, the European Union's Seventh Framework Programme FP7/ REGPOT-2012-2013.1 [grant agreement number 316265], BIOCAPS, the Portuguese Foundation for Science and Technology (FCT) under the strategic funding of UID/BIO/04469/2013 unit, the FCT and the European Community fund FEDER, through Programme COMPETE, under the scope of the Project RECI/BBB- EBI/0179/2012 [FCOMP-010124-FEDER-027462]. SING group also thanks CITI (Centro de Investigación, Transferencia e Innovación) from University of Vigo for hosting its IT infrastructure. The authors also acknowledge FCT for the PhD Grant to Paula Jorge [grant number SFRH/BD/88192/2012]. M. Pérez-Pérez and G. Pérez Rodríguez were supported by pre-doctoral fellowships from the Xunta de Galicia and the University of ...

Aggregates of Pseudomonas aeruginosa form a protective barrier against antibiotics and the immune system. These barriers, known as biofilms, are associated with several infectious diseases. One of the main components of these biofilms is alginate, a homo- and hetero-polysaccharide that consists of β-D-mannuronate (M) and α-L-guluronate (G) units. Alginate lyases degrade this sugar and have been proposed as biotherapeutic agents to dissolve P. aeruginosa biofilms. However, there are contradictory reports in the literature regarding the efficacy of alginate lyases against biofilms and their synergistic effect with antibiotics. We found that most positive reports used a commercial crude extract from Flavobacterium multivorum as the alginate lyase source. By using anion exchange chromatography coupled to nano LC MS/MS, we identified two distinct enzymes in this extract, one has both polyM and polyG (polyM/G) degradation activities and it is similar in sequence to a broad-spectrum alginate lyase from Flavobacterium sp. S20 (Alg2A). The other enzyme has only polyG activity and it is similar in sequence to AlyA1 from Zobellia galactanivorans. By characterizing both of these enzymes together with three recombinant alginate lyases (a polyM, a polyG and a polyM/G), we showed that only enzymes with polyM/G activity such as Alg2A and A1-II' (alginate lyase from Sphingomonas sp.) are effective in dissolving biofilms. Furthermore, both activities are required to have a synergistic effect with antibiotics. ; We acknowledge support of the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under agreement No 670216 (MYCOCHASSIS), the Spanish Ministry of Economy and Competitiveness and Fondo Europeo de Desarrollo Regional (MINECO-FEDER) (BIO2015-63557-R), 'Centro de Excelencia Severo Ochoa 2013-2017', FEDER project from Instituto Carlos III (ISCIII, Acción Estratégica en Salud 2016) (reference CP16/00094) and "Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya / CERCA programme" (2014SGR678 and 2017SGR1079). The CRG/UPF Proteomics Unit is part of the "Plataforma de Recursos Biomoleculares y Bioinformáticos (ProteoRed)" supported by grant PT13/0001 of Instituto de Salud Carlos III from the Spanish Government.

AbstractThe present study aims to integrate the benefits of plaque assay using a novel phage mix with phylogenetic and molecular analysis for detecting Pseudomonas aeruginosa in water. Three phages were isolated and the transmission electron microscope related their morphological resemblance to those of Siphoviridae and Podoviridae families, while molecular analysis showed different cp‐gene sizes. The Phage mix was highly specific (86.0%), and data misleading didn't exceed 14.0% compared to membrane filter assay (39.2%). Time elapsed for test completion required 24 h. Identified P. aeruginosa were verified using 16S‐rDNA. Nucleotide sequence data for both phages and bacteria were submitted to the NCBI GenBank database, USA and gained their accession numbers. Concluding remarks highlight the potential of plaque assay as specific, simple and rapid method. The study recommended future efforts to isolate and characterize new phages for detecting other bacterial pathogens of public health concern to control water pollution and maintain adequate hygiene.

AbstractMicrobial biofilms are complex communities that form when planktonic bacterial species attach to surfaces in many settings where they can provide a source of pathogenicity. The relative ineffectiveness of conventional disinfectants such as free chlorine and monochloramine for the inactivation of some species found in water has led to evaluation of alternative disinfectants for drinking and wastewater treatment. In recent years, novel pulsed power electrotechnologies have been introduced and are being considered as possible alternatives to current methods for inactivating problematic species in water. This study focuses on the ultraviolet (UV) inactivation of bacterial biofilms using a pulsed UV light approach as a potential disinfection method for water treatment operating systems. Biofilms were stimulated to form attached to polyvinyl chloride coupons using a recommended Centre for Disease Control biofilm reactor followed by exposure to a range of UV doses. Findings show that this method is highly effective at inactivating both planktonic and biofilm cells with significant inactivation rates obtained for both test species. Specifically, a 7.2 and 5.9 log10 inactivation was achieved with up to 21.6 μJ/cm2 UV for Pseudomonas aeruginosa and Staphylococcus aureus, respectively. Findings from this study highlight the effectiveness of pulsed UV for the inactivation of Pseudomonas biofilms among other test species. Research conducted by this group suggests that this pulsed UV system may offer a useful method for the disinfection of drinking and wastewater supplies.