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Journal of Visualized Experiments : JoVE May 2020Swarming is a form of surface motility observed in many bacterial species including Pseudomonas aeruginosa and Escherichia coli. Here, dense populations of bacteria move...
Swarming is a form of surface motility observed in many bacterial species including Pseudomonas aeruginosa and Escherichia coli. Here, dense populations of bacteria move over large distances in characteristic tendril-shaped communities over the course of hours. Swarming is sensitive to several factors including medium moisture, humidity, and nutrient content. In addition, the collective stress response, which is observed in P. aeruginosa that are stressed by antibiotics or bacteriophage (phage), repels swarms from approaching the area containing the stress. The methods described here address how to control the critical factors that affect swarming. We introduce a simple method to monitor swarming dynamics and the collective stress response with high temporal resolution using a flatbed document scanner, and describe how to compile and perform a quantitative analysis of swarms. This simple and cost-effective method provides precise and well-controlled quantification of swarming and may be extended to other types of plate-based growth assays and bacterial species.
Topics: Anti-Bacterial Agents; Bacteriophages; Cost-Benefit Analysis; Pseudomonas aeruginosa; Stress, Physiological; Time-Lapse Imaging
PubMed: 32510504
DOI: 10.3791/60915 -
BioMed Research International 2015Very few studies have been conducted on alkaline adaptation of Gram-negative alkaliphiles. The reversed difference of H(+) concentration across the membrane will make... (Review)
Review
Very few studies have been conducted on alkaline adaptation of Gram-negative alkaliphiles. The reversed difference of H(+) concentration across the membrane will make energy production considerably difficult for Gram-negative as well as Gram-positive bacteria. Cells of the alkaliphilic Gram-negative bacterium Pseudomonas alcaliphila AL15-21(T) grown at pH 10 under low-aeration intensity have a soluble cytochrome c content that is 3.6-fold higher than that of the cells grown at pH 7 under high-aeration intensity. Cytochrome c-552 content was higher (64% in all soluble cytochromes c) than those of cytochrome c-554 and cytochrome c-551. In the cytochrome c-552-dificient mutant grown at pH 10 under low-aeration intensity showed a marked decrease in μ max [h(-1)] (40%) and maximum cell turbidity (25%) relative to those of the wild type. Considering the high electron-retaining abilities of the three soluble cytochromes c, the deteriorations in the growth of the cytochrome c-552-deficient mutant could be caused by the soluble cytochromes c acting as electron storages in the periplasmic space of the bacterium. These electron-retaining cytochromes c may play a role as electron and H(+) condenser, which facilitate terminal oxidation at high pH under air-limited conditions, which is difficult to respire owing to less oxygen and less H(+).
Topics: Adaptation, Physiological; Alkalies; Bacterial Proteins; Cytochrome c Group; Energy Metabolism; Hydrogen-Ion Concentration; Oxidation-Reduction; Pseudomonas
PubMed: 25705691
DOI: 10.1155/2015/847945 -
ELife Nov 2019Microscopic water films allow bacteria to survive the seemingly dry surface of plant leaves.
Microscopic water films allow bacteria to survive the seemingly dry surface of plant leaves.
Topics: Plant Leaves; Pseudomonas fluorescens
PubMed: 31674912
DOI: 10.7554/eLife.52123 -
Folia Microbiologica Jul 2018Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as... (Review)
Review
Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.
Topics: Anti-Bacterial Agents; Biofilms; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Humans; Models, Biological; Polysaccharides, Bacterial; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 29352409
DOI: 10.1007/s12223-018-0585-4 -
Current Microbiology Dec 2020Due to its ubiquity, ability to form biofilms, and acquire resistance mechanisms, Pseudomonas spp. become one of the major challenge for healthcare settings and food...
Due to its ubiquity, ability to form biofilms, and acquire resistance mechanisms, Pseudomonas spp. become one of the major challenge for healthcare settings and food industry. The aims of this study were to assess the biofilm production of Pseudomonas spp. recovered from clinical and food specimens and to evaluate their antimicrobial resistance. A total of 108 isolates of Pseudomonas spp. were included in the study, 48 being clinical isolates recovered from patients admitted to four tertiary care hospitals throughout Serbia and 60 were isolated from the bulk tank milk samples and meat carcasses. Biofilm production was analyzed by microtiter plate assay. Antimicrobial susceptibility was evaluated by disk diffusion method according to the CLSI guidelines, while class A and B β-lactamases encoding genes were screened by PCR. A total of 98 (90.7%) strains were biofilm producers (moderate producer: 68, 69.4%; strong producer: 8, 8.2%). Although a slightly higher percentage of clinical isolates were biofilm producers (91.7%) compared to food isolates (90%), statistical significance was not observed (P > 0.05). The proportion of carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates was significantly higher among clinical (42%) isolates compared to food (1.7%) Pseudomonads (P < 0.05). The bla and bla genes were found in ESBL (seven isolates) and MBL (two isolates) production, respectively. In the present study, we confirmed that biofilm formation was highly present in both clinical and food Pseudomonas spp. irrespective of the prior existence of resistance genes. Additionally, clinical settings pose a major reservoir of MDR Pseudomonas spp. and especially CRPA isolates.
Topics: Anti-Bacterial Agents; Biofilms; Drug Resistance, Bacterial; Food Microbiology; Humans; Microbial Sensitivity Tests; Pseudomonas; Pseudomonas Infections; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 33057751
DOI: 10.1007/s00284-020-02236-4 -
Journal of Proteome Research Jul 2021pv. causes halo blight disease in the common bean . The bacterium invades the leaf apoplast and uses a type III secretion system to inject effector proteins into a...
pv. causes halo blight disease in the common bean . The bacterium invades the leaf apoplast and uses a type III secretion system to inject effector proteins into a bean cell to interfere with the bean immune system. Beans counter with resistance proteins that can detect effectors and coordinate effector-triggered immunity responses transduced by salicylic acid, the primary defense hormone. Effector-triggered immunity halts bacterial spread, but its direct effect on the bacterium is not known. In this study, mass spectrometry of bacterial infections from immune and susceptible beans revealed that immune beans inhibited the accumulation of bacterial proteins required for virulence, secretion, motility, chemotaxis, quorum sensing, and alginate production. Sets of genes encoding these proteins appeared to function in operons, which implies that immunity altered the coregulated genes in the bacterium. Immunity also reduced amounts of bacterial methylglyoxal detoxification enzymes and their transcripts. Treatment of bacteria with salicylic acid, the plant hormone produced during immunity, reduced bacterial growth, decreased gene expression for methylglyoxal detoxification enzymes, and increased bacterial methylglyoxal concentrations . Increased methylglyoxal concentrations reduced bacterial reproduction. These findings support the hypothesis that plant immunity involves the chemical induction of adverse changes to the bacterial proteome to reduce pathogenicity and to cause bacterial self-toxicity.
Topics: Bacterial Proteins; Phaseolus; Plant Diseases; Plant Immunity; Pseudomonas; Pseudomonas syringae; Virulence
PubMed: 34097416
DOI: 10.1021/acs.jproteome.1c00232 -
Applied and Environmental Microbiology Sep 2021Opportunistic pathogens can linger on surfaces in hospital and building plumbing environments, leading to infections in at-risk populations. Furthermore,...
Opportunistic pathogens can linger on surfaces in hospital and building plumbing environments, leading to infections in at-risk populations. Furthermore, biofilm-associated bacteria are protected from removal and inactivation protocols such as disinfection. Bacteriophages show promise as tools to treat antibiotic-resistant infections. As such, phages may also be useful in environmental applications to prevent newly acquired infections. In the current study, the potential of synergies between bacteriophage and chemical disinfection against the opportunistic pathogen Pseudomonas aeruginosa was assessed under various conditions. Specifically, surface-associated P. aeruginosa was treated with various concentrations of phages (P1 or JG004), chemical disinfectants (sodium hypochlorite or benzalkonium chloride), or combined sequential treatments under three distinct attachment models (spot inoculations, dry biofilms, and wet biofilms). Phages were very effective at removing bacteria in spot inoculations (>3.2 log removal) and wet biofilms (up to 2.6 log removal), while phages prevented the regrowth of dry biofilms in the application time. In addition, phage treatment followed by chemical disinfection inactivated P. aeruginosa cells under wet biofilm conditions better than either treatment alone. This effect was hindered when chemical disinfection was applied first, followed by phage treatment, suggesting that the additive benefits of combination treatments are lost when phage is applied last. Furthermore, we confirm previous evidence of greater phage tolerance to benzalkonium chloride than to sodium hypochlorite, informing choices for combination phage-disinfectant approaches. Overall, this paper further supports the potential of using combination phage and chemical disinfectant treatments to improve the inactivation of surface-associated P. aeruginosa. Phages are already utilized in the health care industry to treat antibiotic-resistant infections, such as those on implant-associated biofilms and in compassionate-care cases. Phage treatment could also be a promising new tool to control pathogens in the built environment, preventing infections from occurring. This study shows that phages can be combined effectively with chemical disinfectants to improve the removal of wet biofilms and bacteria spotted onto surfaces while preventing regrowth in dry biofilms. This has the potential to improve pathogen containment within the built environment and drinking water infrastructure to prevent infections by opportunistic pathogens.
Topics: Bacteriophages; Benzalkonium Compounds; Biofilms; Disinfectants; Disinfection; Plastics; Pseudomonas aeruginosa; Sodium Hypochlorite
PubMed: 34347517
DOI: 10.1128/AEM.00980-21 -
Journal of Food Protection Jan 2021Kitfo is a version of beef tartar widely consumed in the Ethiopian community. It is made from raw minced beef and a blend of powdered spice and butter. Although previous...
ABSTRACT
Kitfo is a version of beef tartar widely consumed in the Ethiopian community. It is made from raw minced beef and a blend of powdered spice and butter. Although previous studies have shown that kitfo contains several bacteria that are of public health concern, the status of their antibiotic resistance is not known. In this study, the antibiotic resistance of bacterial isolates from 26 retail kitfo samples obtained from the Washington metropolitan area was analyzed. Characterization and antibiotic sensitivity of the isolates were determined by the Vitek 2 system and pulsed-field gel electrophoresis was used to delineate the intraspecies variations. Of the isolates, 59% were resistant to two or more antibiotics. Acinetobacter calcoaceticus and Pseudomonas luteola were multidrug resistant to the classes of β-lactam, cephalosporins, and nitrofurantoin. The antibiotic susceptibility profile of the isolates was cefazolin (59%), cefoxitin (50%), ampicillin (32%), and nitrofuran (18%). Most isolates (75%) were Enterobacteriaceae, whereas only 3.8 and 2.6% were Pseudomonadaceae and Moraxellaceae, respectively. Of the Enterobacteriaceae, Enterobacter cloacae, Escherichia coli, and Klebsiella spp. were the most predominant. All isolates except Klebsiella spp. showed high genetic variation (>65%). This study implicates for the first time kitfo as a potential reservoir of antibiotic-resistant bacteria.
Topics: Animals; Anti-Bacterial Agents; Cattle; Dental Calculus; Drug Resistance, Bacterial; Drug Resistance, Microbial; Microbial Sensitivity Tests; Prevalence; Pseudomonas; Washington; beta-Lactamases
PubMed: 33411928
DOI: 10.4315/JFP-20-230 -
Journal of Global Antimicrobial... Mar 2020Pseudomonas aeruginosa is the most frequent infectious agent in cystic fibrosis patients. P. aeruginosa resistance to first line antibiotics limits therapeutic options,... (Comparative Study)
Comparative Study
OBJECTIVES
Pseudomonas aeruginosa is the most frequent infectious agent in cystic fibrosis patients. P. aeruginosa resistance to first line antibiotics limits therapeutic options, but the therapeutic potential of older generation antibiotics, such as fosfomycin is under investigation. Fosfomycin does not belong to any other antibiotic class and acts by inhibiting the biosynthesis of the bacterial cell wall during the initial phases. A major problem for the use of fosfomycin against P. aeruginosa is the absence of a clinical breakpoint, the last one of 32 μg/mL was proposed in 2013 by the CA-SFM (Comité de l'Antibiogramme de la Société Française de Microbiologie).
METHODS
Sixty-one strains of P. aeruginosa (thirty mucoid and thirty-one non mucoid) were collected from respiratory samples of cystic fibrosis patients. All isolates were identified by MALDI-TOF (Bruker, Bremen, Germany). Fosfomycin MICs against P. aeruginosa were measured using an automated system and confirmed by the gold standard method.
RESULTS
There was no significant difference between mucoid and non-mucoid strains. MIC distribution and susceptibility rates were obtained by agar dilution method and from this data we measured MIC50 and MIC90 which were equal to 32 μg/mL and 64 μg/mL, respectively. From automated method results we measured a very major error (VME), major error (ME) and categorical agreement (CA) which were equal to 0%, 11% and 89%, respectively. Comparing automated and agar dilution methods, a Cohen's kappa equal to 73% (0.726) was measured.
CONCLUSIONS
Our data suggest that fosfomycin has good effect against mucoid and non-mucoid strains of P. aeruginosa and automated systems can be implemented in clinical microbiology laboratories to assess fosfomycin with rapid and reproducible results.
Topics: Automation, Laboratory; Cystic Fibrosis; Fosfomycin; Humans; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 32105800
DOI: 10.1016/j.jgar.2020.02.014 -
Molecules (Basel, Switzerland) Oct 2017Materials used in ossicular replacement prostheses must possess appropriate biological properties, such as biocompatibility, stability, no cytotoxicity. Due to the risk...
Materials used in ossicular replacement prostheses must possess appropriate biological properties, such as biocompatibility, stability, no cytotoxicity. Due to the risk of infection (otitis media and chronic otitis media), it is desirable to use an antibacterial agent for illness prevention during the ossicular reconstruction. The goal of this work was to observe biological properties of a new composite prosthesis made of ABS containing silver nanoparticles (AgNPs 45T). Samples for biological tests and then a prototype of middle ear prosthesis were prepared using injection moulding and extrusion techniques. In vitro experiments were carried out to assess bactericidal efficacy against and standard strains, cell proliferation, viability and cytotoxicity, using Hs680.Tr. fibroblast cells. Surface parameters of the samples were evaluated, including roughness and wettability. The silver ions were continually released from the polymer in aqueous solution. The silver ions release was measured as increasing with time and concentration of the silver nanoparticles in the polymer matrix. No cytotoxicity effect was observed, while bactericidal efficacy was noticed for silver nanoparticles. The roughness studies showed an increase in roughness for the samples with silver nanoparticles. All polymer and composite materials containing silver nanoparticles showed hydrophilic properties. The composites were found to release silver ions at a concentration level capable of rendering the antimicrobial efficacy even with the lowest concentration of silver nanoparticles in the material. Our results demonstrate that middle ear prosthesis made of polymer and silver nanoparticles may eliminate bacteria during inflammation in the middle ear.
Topics: Acrylic Resins; Anti-Bacterial Agents; Butadienes; Cell Line; Cell Proliferation; Cell Survival; Fibroblasts; Humans; Metal Nanoparticles; Microbial Sensitivity Tests; Ossicular Prosthesis; Polystyrenes; Prosthesis-Related Infections; Pseudomonadaceae; Silver; Staphylococcus aureus; Surface Properties
PubMed: 28994723
DOI: 10.3390/molecules22101681