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Applied and Environmental Microbiology Mar 2021Perturbation of natural microbial communities by antimicrobials, such as triclosan, can result in selection for antibiotic tolerance, which is of particular concern when...
Perturbation of natural microbial communities by antimicrobials, such as triclosan, can result in selection for antibiotic tolerance, which is of particular concern when pathogens are present. Members of the genus are found in many natural microbial communities and frequently demonstrate increased abundance following triclosan exposure. The pathogen and well-studied model organism exhibits high triclosan tolerance; however, it is unknown if all species share this trait or if there are susceptible strains. We characterized the triclosan tolerance phenotypes of diverse isolates obtained from triclosan-exposed built environments and identified both tolerant and sensitive strains. High tolerance is associated with carriage of the enoyl-acyl carrier reductase (ENR) isozyme gene , compared to the lesser protective effects of efflux or presence of ENRs. Given its unique importance, we examined distribution throughout species using large-scale phylogenomic analyses. We find presence or absence is largely invariant at the species level but demonstrates multiple gain and loss events in its evolutionary history. We further provide evidence of its presence on mobile genetic elements. Our results demonstrate the surprising variability in triclosan tolerance in and confirm to be a useful indicator for high triclosan tolerance in These findings provide a framework for better monitoring of in triclosan-exposed environments and interpreting effects on species and gene composition. Closely related species are typically assumed to demonstrate similar phenotypes driven by underlying conserved genotypes. When monitoring for the effect of antimicrobials on the types of species that may be selected for, this assumption may prove to be incorrect, and identification of additional genetic markers may be necessary. We isolated several phylogenetically diverse members of from indoor environments and tested their phenotypic tolerance toward the commonly used antimicrobial triclosan. Although isolates are broadly regarded to be highly triclosan tolerant, we demonstrate the presence of both triclosan-tolerant and -susceptible strains, separated by a difference in tolerance of nearly 3 orders of magnitude. Bioinformatic and experimental investigation demonstrated that the presence of the gene was associated with high tolerance. We demonstrate that is not evenly distributed in all species and that its presence could be a useful predictor of high triclosan tolerance suitable for antimicrobial monitoring efforts involving triclosan.
Topics: Anti-Bacterial Agents; Anti-Infective Agents, Local; Drug Resistance, Bacterial; Pseudomonas; Species Specificity; Triclosan
PubMed: 33483311
DOI: 10.1128/AEM.02924-20 -
Molecules (Basel, Switzerland) Feb 2023Phenazines are a large group of heterocyclic nitrogen-containing compounds with demonstrated insecticidal, antimicrobial, antiparasitic, and anticancer activities. These... (Review)
Review
Phenazines are a large group of heterocyclic nitrogen-containing compounds with demonstrated insecticidal, antimicrobial, antiparasitic, and anticancer activities. These natural compounds are synthesized by several microorganisms originating from diverse habitats, including marine and terrestrial sources. The most well-studied producers belong to the genus, which has been extensively investigated over the years for its ability to synthesize phenazines. This review is focused on the research performed on pseudomonads' phenazines in recent years. Their biosynthetic pathways, mechanism of regulation, production processes, bioactivities, and applications are revised in this manuscript.
Topics: Pseudomonas; Phenazines; Ecosystem; Biosynthetic Pathways
PubMed: 36771036
DOI: 10.3390/molecules28031368 -
Advances in Microbial Physiology 2020The synthetic s-triazines are abundant, nitrogen-rich, heteroaromatic compounds used in a multitude of applications including, herbicides, plastics and polymers, and... (Review)
Review
The synthetic s-triazines are abundant, nitrogen-rich, heteroaromatic compounds used in a multitude of applications including, herbicides, plastics and polymers, and explosives. Their presence in the environment has led to the evolution of bacterial catabolic pathways in bacteria that allow use of these anthropogenic chemicals as a nitrogen source that supports growth. Herbicidal s-triazines have been used since the mid-twentieth century and are among the most heavily used herbicides in the world, despite being withdrawn from use in some areas due to concern about their safety and environmental impact. Bacterial catabolism of the herbicidal s-triazines has been studied extensively. Pseudomonas sp. strain ADP, which was isolated more than thirty years after the introduction of the s-triazine herbicides, has been the model system for most of these studies; however, several alternative catabolic pathways have also been identified. Over the last five years, considerable detail about the molecular mode of action of the s-triazine catabolic enzymes has been uncovered through acquisition of their atomic structures. These structural studies have also revealed insights into the evolutionary origins of this newly acquired metabolic capability. In addition, s-triazine-catabolizing bacteria and enzymes have been used in a range of applications, including bioremediation of herbicides and cyanuric acid, introducing metabolic resistance to plants, and as a novel selectable marker in fermentation organisms. In this review, we cover the discovery and characterization of bacterial strains, metabolic pathways and enzymes that catabolize the s-triazines. We also consider the evolution of these new enzymes and pathways and discuss the practical applications that have been considered for these bacteria and enzymes. One Sentence Summary: A detailed understanding of bacterial herbicide catabolic enzymes and pathways offer new evolutionary insights and novel applied tools.
Topics: Bacteria; Bacterial Proteins; Biodegradation, Environmental; Evolution, Molecular; Gene Expression Regulation, Bacterial; Herbicides; Metabolic Networks and Pathways; Models, Biological; Protein Conformation; Pseudomonas; Triazines
PubMed: 32408946
DOI: 10.1016/bs.ampbs.2020.01.004 -
International Microbiology : the... Dec 2019Bacterial diseases are the main cause of high economic loss in aquaculture, particularly gram-negative bacteria. This study was conducted for the isolation and...
Bacterial diseases are the main cause of high economic loss in aquaculture, particularly gram-negative bacteria. This study was conducted for the isolation and identification of Aeromonas and Pseudomonas spp. from diseased fish. Twenty-two Aeromonas and sixteen Pseudomonas isolates were recovered from diseased Nile tilapia (Oreochromis niloticus) raised in eight earthen ponds in Elhox, Metoubes, Kafrelsheikh, Egypt. The recovered isolates were further identified using PCR as 22 Aeromonas hydrophila, 11 Pseudomonas aeruginosa, and 5 Pseudomonas fluorescens isolates. The 22 A. hydrophila isolates were screened for the presence of four virulence genes. Sixteen of the isolates (72.72%) were positive for the aerolysin gene (aer); 4 (18.18%) harbored the cytotoxic enterotoxin gene (act); and 2 (9.09%) carried the hemolysin A gene (hylA) while the cytotonic heat-stable enterotoxin gene (ast) was absent from all the tested isolates. The pathogenicity test indicated the direct relationship between the mortality percentage and the genotype of the tested A. hydrophila isolates as the mortality rates were 63.3 and 73.3% for isolates with two virulence genes (aer & act, and aer and hylA, respectively), followed by 40, 53.3, and 56.6% for isolates with only one virulence gene (hylA, act, and aer, respectively) and 20% for isolates lacking virulence genes. Based on the sensitivity test, the multi-antibiotic resistance profiles were as follows: 90.9% of the A. hydrophila isolates were sensitive to florfenicol and doxycycline; then 68.18% were susceptible to oxytetracycline, norfloxacin, and ciprofloxacin; and 63.63% were susceptible to sulfamethoxazole-trimethoprim, while only 27.27 and 4.5% were sensitive to erythromycin and cephradine, respectively, and all the isolates were resistant to amoxicillin and ampicillin.
Topics: Aeromonas hydrophila; Animals; Bacterial Proteins; Cichlids; Fish Diseases; Gram-Negative Bacterial Infections; Pseudomonas; Virulence; Virulence Factors
PubMed: 30989358
DOI: 10.1007/s10123-019-00075-3 -
Brazilian Journal of Biology = Revista... 2021The effects of Calcium (Ca+2) on virulence and some parameters should be analyzed in this study. Pseudomonas aeruginosa Gram (-) and Bacillus cereus Gram (+) were used....
The effects of Calcium (Ca+2) on virulence and some parameters should be analyzed in this study. Pseudomonas aeruginosa Gram (-) and Bacillus cereus Gram (+) were used. Both bacteria are soil bacteria. In this study; the effect of Ca+2 on protease, amylase, LasB elastolytic assay, H2O2, pyorubin and biofilm on metabolites of these bacteria were investigated during 24 hour time. In this study, the effect of Ca+2 on the production of some secondary metabolites on P. aeruginosa and B. cereus was investigated and presented for the first time by us.
Topics: Bacillus cereus; Calcium; Hydrogen Peroxide; Pseudomonas; Pseudomonas aeruginosa
PubMed: 34133571
DOI: 10.1590/1519-6984.243189 -
Frontiers in Cellular and Infection... 2021Bacterial biofilms are important medically, environmentally and industrially and there is a need to understand the processes that govern functional synergy and dynamics...
Bacterial biofilms are important medically, environmentally and industrially and there is a need to understand the processes that govern functional synergy and dynamics of species within biofilm communities. Here, we have used a model, mixed-species biofilm community comprised of PAO1, Pf-5 and KP1. This biofilm community displays higher biomass and increased resilience to antimicrobial stress conditions such as sodium dodecyl sulfate and tobramycin, compared to monospecies biofilm populations. is present at low proportions in the community and yet, it plays a critical role in community function, suggesting it acts as a keystone species in this community. To determine the factors that regulate community composition, we focused on because of its pronounced impact on community structure and function. Specifically, we evaluated the role of the N-acyl homoserine lactone (AHL) dependent quorum sensing (QS) system of PAO1, which regulates group behaviors including biofilm formation and the production of effector molecules. We found that mixed species biofilms containing QS mutants had significantly altered proportions of and populations compared to mixed species biofilms with the wild type . Similarly, inactivation of QS effector genes, e.g. and , also governed the relative species proportions. While the absence of QS did not alter the proportions of the two species in dual species biofilms of and , it resulted in significantly lower proportions of in dual species biofilms with . These observations suggest that QS plays an important role in modulating community biofilm structure and physiology and affects interspecific interactions.
Topics: Acyl-Butyrolactones; Biofilms; Pseudomonas; Pseudomonas aeruginosa; Quorum Sensing
PubMed: 33869078
DOI: 10.3389/fcimb.2021.646991 -
Clinical Microbiology and Infection :... Mar 2021This study aims to investigate ampicillin catabolism in a pandrug-resistant strain, Pseudomonas sp. MR 02 of P. putida lineage.
OBJECTIVES
This study aims to investigate ampicillin catabolism in a pandrug-resistant strain, Pseudomonas sp. MR 02 of P. putida lineage.
METHODS
The characterization of carbapenem resistance was done following the standard protocol. The broth macrodilution method was used to determine the MIC values of antimicrobial agents both in the presence and in the absence of phenylalanine-β-naphthylamide. High MIC values (>10 000 mg/L) of ampicillin led to speculation that it may serve as a growth substrate, and thus minimal medium was used to evaluate ampicillin as a nutrient. The growth of MR 02 was measured in minimal medium in the presence or absence of 0.4 mM EDTA, supplemented with ampicillin as sole carbon, nitrogen and energy source. RNA-seq was used to generate expression profiles of genes in ampicillin or glucose-grown cells. The bla gene of MR 02 was cloned in the pHSG398 vector and expressed in Escherichia coli DH5α.
RESULTS
Phenotypic analysis along with genome sequence data identifies Pseudomonas sp. MR 02 as a pandrug-resistant strain. Transcriptome data has revealed that bla was among the top 50 differentially expressed genes in ampicillin grown cells compared to the glucose grown cells in the minimal medium. Heterologous expression of bla gene in E. coli DH5α enabled its growth and subsistence on ampicillin as the sole source of carbon and energy.
DISCUSSION
The ability of a pandrug-resistant Pseudomonas sp. MR 02 to consume ampicillin for growth has a huge implication in the bioremediation of β-lactam residues in the environment.
Topics: Ampicillin; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Microbial Sensitivity Tests; Pseudomonas; beta-Lactamases
PubMed: 33160034
DOI: 10.1016/j.cmi.2020.10.032 -
The biotechnological potential of marine bacteria in the novel lineage of Pseudomonas pertucinogena.Microbial Biotechnology Jan 2020Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully... (Review)
Review
Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully exploited for industrial applications. Recently, a group of Pseudomonas species isolated from extreme habitats or living in association with algae or sponges were clustered in the newly established Pseudomonas pertucinogena lineage. Remarkably for the predominantly terrestrial genus Pseudomonas, more than half (9) of currently 16 species within this lineage were isolated from marine or saline habitats. Unlike other Pseudomonas species, they seem to have in common a highly specialized metabolism. Furthermore, the marine members apparently possess the capacity to produce biomolecules of biotechnological interest (e.g. dehalogenases, polyester hydrolases, transaminases). Here, we summarize the knowledge regarding the enzymatic endowment of the marine Pseudomonas pertucinogena bacteria and report on a genomic analysis focusing on the presence of genes encoding esterases, dehalogenases, transaminases and secondary metabolites including carbon storage compounds.
Topics: Bacteria; Biotechnology; Ecosystem; Pseudomonas
PubMed: 29943398
DOI: 10.1111/1751-7915.13288 -
International Journal of Systematic and... Nov 2020The taxonomic classification of species has been revised and updated several times. This study utilized average nucleotide identity (ANI) and digital DNA-DNA...
The taxonomic classification of species has been revised and updated several times. This study utilized average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) cutoff values of 95 and 70 %, respectively, to re-identify the species of strains deposited in GenBank as , and . Of the 264 deposited strains, 259 were correctly identified as , but the remaining five were not. All 28 deposited strains had been incorrectly identified as . Four of these strains were re-identified, including two as and one each as and , but the remaining 24 could not be re-identified. Similarly, all 35 deposited strains had been incorrectly identified as . Nineteen of these strains were re-identified, including 12 as , four as and one each as , and . These results strongly suggest that bacteria should be identified using ANI and dDDH analyses based on whole genome sequencing when species are initially deposited in GenBank/DDBJ/EMBL databases.
Topics: Bacterial Typing Techniques; DNA, Bacterial; Databases, Nucleic Acid; Nucleic Acid Hybridization; Pseudomonas aeruginosa; Pseudomonas fluorescens; Pseudomonas putida; Sequence Analysis, DNA; Whole Genome Sequencing
PubMed: 32936751
DOI: 10.1099/ijsem.0.004468 -
Cell Metabolism Jun 2020Itaconate is an immunometabolite with anti-inflammatory and anti-microbial properties. Riquelme et al. (2020) demonstrate that pathogenic Pseudomonas aeruginosa drives...
Itaconate is an immunometabolite with anti-inflammatory and anti-microbial properties. Riquelme et al. (2020) demonstrate that pathogenic Pseudomonas aeruginosa drives itaconate production by macrophages, which it then uses as a carbon source for biofilm formation, allowing it to persist during infection and suppress inflammation.
Topics: Biofilms; Pseudomonas; Pseudomonas aeruginosa; Succinates
PubMed: 32492389
DOI: 10.1016/j.cmet.2020.05.005