Two Lineages of Pseudomonas aeruginosa Filamentous Phages: Structural Uniformity over Integration Preferences

Abstract Pseudomonas aeruginosa filamentous (Pf) bacteriophages are important factors contributing to the pathogenicity of this opportunistic bacterium, including biofilm formation and suppression of bacterial phagocytosis by macrophages. In addition, the capacity of Pf phages to form liquid crystal structures and their high negative charge density makes them potent sequesters of cationic antibacterial agents, such as aminoglycoside antibiotics or host antimicrobial peptides. Therefore, Pf phages have been proposed as a potential biomarker for risk of antibiotic resistance development. The majority of studies describing biological functions of Pf viruses have been performed with only three of them: Pf1, Pf4, and Pf5. However, our analysis revealed that Pf phages exist as two evolutionary lineages (I and II), characterized by substantially different structural/morphogenesis properties, despite sharing the same integration sites in the host chromosomes. All aforementioned model Pf phages are members of the lineage I. Hence, it is reasonable to speculate that their interactions with P. aeruginosa and impact on its pathogenicity may be not completely extrapolated to the lineage II members. Furthermore, in order to organize the present numerical nomenclature of Pf phages, we propose a more informative approach based on the insertion sites, that is, Pf-tRNA-Gly, -Met, -Sec, -tmRNA, and -DR (direct repeats), which are fully compatible with one of five types of tyrosine integrases/recombinases XerC/D carried by these viruses. Finally, we discuss possible evolutionary mechanisms behind this division and consequences from the perspective of virus–virus, virus–bacterium, and virus–human interactions.

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Pseudomonas aeruginosa PAO 1 In Vitro Time–Kill Kinetics Using Single Phages and Phage Formulations—Modulating Death, Adaptation, and Resistance

Antibiotics ◽

10.3390/antibiotics10070877 ◽

2021 ◽

Vol 10 (7) ◽

pp. 877

Author(s):

Ana Mafalda Pinto ◽

Alberta Faustino ◽

Lorenzo M. Pastrana ◽

Manuel Bañobre-López ◽

Sanna Sillankorva

Keyword(s):

Pseudomonas Aeruginosa ◽

Phage Therapy ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Chronic Infections ◽

Swarming Motility ◽

Resistance Development ◽

Healthcare Settings ◽

Time Kill

Pseudomonas aeruginosa is responsible for nosocomial and chronic infections in healthcare settings. The major challenge in treating P. aeruginosa-related diseases is its remarkable capacity for antibiotic resistance development. Bacteriophage (phage) therapy is regarded as a possible alternative that has, for years, attracted attention for fighting multidrug-resistant infections. In this work, we characterized five phages showing different lytic spectrums towards clinical isolates. Two of these phages were isolated from the Russian Microgen Sextaphage formulation and belong to the Phikmvviruses, while three Pbunaviruses were isolated from sewage. Different phage formulations for the treatment of P. aeruginosa PAO1 resulted in diversified time–kill outcomes. The best result was obtained with a formulation with all phages, prompting a lower frequency of resistant variants and considerable alterations in cell motility, resulting in a loss of 73.7% in swimming motility and a 79% change in swarming motility. These alterations diminished the virulence of the phage-resisting phenotypes but promoted their growth since most became insensitive to a single or even all phages. However, not all combinations drove to enhanced cell killings due to the competition and loss of receptors. This study highlights that more caution is needed when developing cocktail formulations to maximize phage therapy efficacy. Selecting phages for formulations should consider the emergence of phage-resistant bacteria and whether the formulations are intended for short-term or extended antibacterial application.

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Tackling Virulence of Pseudomonas aeruginosa by the Natural Furanone Sotolon

Antibiotics ◽

10.3390/antibiotics10070871 ◽

2021 ◽

Vol 10 (7) ◽

pp. 871

Author(s):

Mohammed F. Aldawsari ◽

El-Sayed Khafagy ◽

Ahmed Al Saqr ◽

Ahmed Alalaiwe ◽

Hisham A. Abbas ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Virulence Factors ◽

Bacterial Infections ◽

Therapeutic Agent ◽

Bacterial Resistance ◽

Inhibitory Concentration ◽

Bacterial Biofilm ◽

Resistant Bacteria ◽

Resistance Development

The bacterial resistance development due to the incessant administration of antibiotics has led to difficulty in their treatment. Natural adjuvant compounds can be co-administered to hinder the pathogenesis of resistant bacteria. Sotolon is the prevailing aromatic compound that gives fenugreek its typical smell. In the current work, the anti-virulence activities of sotolon on Pseudomonas aeruginosa have been evaluated. P. aeruginosa has been treated with sotolon at sub-minimum inhibitory concentration (MIC), and production of biofilm and other virulence factors were assessed. Moreover, the anti-quorum sensing (QS) activity of sotolon was in-silico evaluated by evaluating the affinity of sotolon to bind to QS receptors, and the expression of QS genes was measured in the presence of sotolon sub-MIC. Furthermore, the sotolon in-vivo capability to protect mice against P. aeruginosa was assessed. Significantly, sotolon decreased the production of bacterial biofilm and virulence factors, the expression of QS genes, and protected mice from P. aeruginosa. Conclusively, the plant natural substance sotolon attenuated the pathogenicity of P. aeruginosa, locating it as a plausible potential therapeutic agent for the treatment of its infections. Sotolon can be used in the treatment of bacterial infections as an alternative or adjuvant to antibiotics to combat their high resistance to antibiotics.

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Development of Resistance in Wild-Type and Hypermutable Pseudomonas aeruginosa Strains Exposed to Clinical Pharmacokinetic Profiles of Meropenem and Ceftazidime Simulated In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00160-07 ◽

2007 ◽

Vol 51 (10) ◽

pp. 3642-3649 ◽

Cited By ~ 19

Author(s):

Beate Henrichfreise ◽

Irith Wiegand ◽

Ingeborg Luhmer-Becker ◽

Bernd Wiedemann

Keyword(s):

Pseudomonas Aeruginosa ◽

Parent Strain ◽

Resistance Mechanisms ◽

In Vitro Models ◽

Wild Type ◽

Resistance Development ◽

Development Of Resistance ◽

Pharmacokinetic Profiles ◽

Mutant Prevention Concentration

ABSTRACT In this study we investigated the interplay of antibiotic pharmacokinetic profiles and the development of mutation-mediated resistance in wild-type and hypermutable Pseudomonas aeruginosa strains. We used in vitro models simulating profiles of the commonly used therapeutic drugs meropenem and ceftazidime, two agents with high levels of antipseudomonal activity said to have different potentials for stimulating resistance development. During ceftazidime treatment of the wild-type strain (PAO1), fully resistant mutants overproducing AmpC were selected rapidly and they completely replaced wild-type cells in the population. During treatment with meropenem, mutants of PAO1 were not selected as rapidly and showed only intermediate resistance due to the loss of OprD. These mutants also replaced the parent strain in the population. During the treatment of the mutator P. aeruginosa strain with meropenem, the slowly selected mutants did not accumulate several resistance mechanisms but only lost OprD and did not completely replace the parent strain in the population. Our results indicate that the commonly used dosing regimens for meropenem and ceftazidime cannot avoid the selection of mutants of wild-type and hypermutable P. aeruginosa strains. For the treatment outcome, including the prevention of resistance development, it would be beneficial for the antibiotic concentration to remain above the mutant prevention concentration for a longer period of time than it does in present regimens.

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Imipenem/Cilastatin/Relebactam Alone and in Combination against Pseudomonas aeruginosa in the In Vitro Pharmacodynamic Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01764-20 ◽

2020 ◽

Vol 64 (12) ◽

Author(s):

Iris H. Chen ◽

David P. Nicolau ◽

Joseph L. Kuti

Keyword(s):

Pseudomonas Aeruginosa ◽

Plasma Concentrations ◽

Multidrug Resistant ◽

Pharmacodynamic Model ◽

Resistance Development ◽

Content Type ◽

Combination Studies ◽

The Mean ◽

Combined Drugs

ABSTRACT Combination therapy may enhance imipenem/cilastatin/relebactam’s (I/R) activity against Pseudomonas aeruginosa and suppress resistance development. Human-simulated unbound plasma concentrations of I/R at 1.25 g every 6 h (h), colistin at 360 mg daily, and amikacin at 25 mg/kg daily were reproduced alone and in combination against six imipenem-nonsusceptible P. aeruginosa isolates in an in vitro pharmacodynamic model over 24 h. For I/R alone, the mean reductions in CFU ± the standard errors by 24 h were −2.52 ± 0.49, −1.49 ± 0.49, −1.15 ± 0.67, and −0.61 ± 0.10 log10 CFU/ml against isolates with MICs of 1/4, 2/4, 4/4, and 8/4 μg/ml, respectively. Amikacin alone also resulted in 24 h CFU reductions consistent with its MIC, while colistin CFU reductions did not differ. Resistant subpopulations were observed after 24 h in 1, 4, and 3 I/R-, colistin-, and amikacin-exposed isolates, respectively. The combination of I/R and colistin resulted in synergistic (n = 1) or additive (n = 2) interactions against three isolates with 24-h CFU reductions ranging from −2.62 to −4.67 log10 CFU/ml. The combination of I/R and amikacin exhibited indifferent interactions against all isolates, with combined drugs achieving −0.51- to −3.33-log10 CFU/ml reductions. No resistant subpopulations were observed during I/R and colistin combination studies, and when added to amikacin, I/R prevented the emergence of amikacin resistance. Against these six multidrug-resistant P. aeruginosa, I/R alone achieved significant CFU reductions against I/R-susceptible isolates. Combinations of I/R plus colistin resulted in additivity or synergy against some P. aeruginosa, whereas the addition of amikacin did not provide further antibacterial efficacy against these isolates.

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Lack of Association between Hypermutation and Antibiotic Resistance Development in Pseudomonas aeruginosa Isolates from Intensive Care Unit Patients

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.9.3573-3575.2004 ◽

2004 ◽

Vol 48 (9) ◽

pp. 3573-3575 ◽

Cited By ~ 43

Author(s):

Olivia Gutiérrez ◽

Carlos Juan ◽

José L. Pérez ◽

Antonio Oliver

Keyword(s):

Cystic Fibrosis ◽

Intensive Care Unit ◽

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Intensive Care ◽

Large Collection ◽

Resistance Development ◽

Icu Patients

ABSTRACT Hypermutation is a common feature of Pseudomonas aeruginosa isolates from chronically infected cystic fibrosis patients that is linked with antibiotic resistance development. In this work, using a large collection of sequential P. aeruginosa isolates from ICU patients, we found that despite the fact that mutational antibiotic resistance development is a frequent outcome, the prevalence of hypermutable strains is low (found in isolates from only 1 of 103 patients) and there is no evidence of coselection of the hypermutable and antibiotic resistance phenotypes.

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Analysis of Retroviral Vector Insertion Sites after T-Cell Directed Gene Therapy.

Blood ◽

10.1182/blood.v104.11.289.289 ◽

2004 ◽

Vol 104 (11) ◽

pp. 289-289 ◽

Cited By ~ 9

Author(s):

Akihiro Konno ◽

G. Jayashree Jagadeesh ◽

Daniele Moratto ◽

Marita Bosticardo ◽

Ingeborg Holt ◽

...

Keyword(s):

T Cell ◽

Gene Transfer ◽

Human Genome ◽

Peripheral Blood ◽

Retroviral Vectors ◽

Peripheral Blood Lymphocytes ◽

Inverse Pcr ◽

Blood Lymphocytes ◽

Integration Sites ◽

Insertion Sites

Abstract Gene transfer into peripheral blood lymphocytes has several potential applications including the correction of genetic diseases and therapeutic approaches for HIV-1 infection and cancer. Integrating gene transfer system based on murine oncoretroviruses are a convenient tool for such strategies. However, the recent occurrence of uncontrolled clonal T cell expansions in two patients treated with retroviral gene transfer for X-linked severe combined immune deficiency has raised the concern of the risk of insertional oncogenesis associated with the clinical use of integrating viral systems. In vitro studies have indicated that murine viral vectors tend to integrate in the vicinity of transcription start regions of the genome, thus providing a possible mechanism for oncogene activation, however, data from clinical gene transfer trials is lacking. We are following patients affected with adenosine deaminase (ADA) deficiency who have received T-lymphocyte-directed, retroviral-mediated gene transfer starting in 1990. The first treated patient received the last infusion of gene-corrected cells 12 years ago, has never shown any sign of lymphoproliferation and still carries ~20% of gene-corrected peripheral blood lymphocytes. We set out to study the integration sites in the cells of this patient with the aim of mapping the regions involved by retroviral integrations, determining their localization with respect to known genes, and assessing whether a preferred pattern could be defined. Genomic DNA was prepared from stored lymphocyte samples dating 1991, 1992, 1995, 1998, 2000, and 2003. By inverse PCR and ligation-mediated PCR, we have identified ~860 bona fide insertion sites. Search for homology within the human genome using BLAT returned ~330 unique hits that involved a variety of genes, including transcription factors and oncogenes (e.g. RUNX1, STAT5, FYN). To evaluate the distribution pattern of these integration sites, 2000 randomly generated data sets of genomic coordinates were assembled and their distribution relative to annotations of the human genome was analyzed. A preliminary comparison of the random distribution to our experimental samples showed that retroviral integrations in cells obtained from the patient were significantly skewed toward regions within 2 kb of genes (p<0.002) and CpG islands (p<0.001). These results suggest that, similar to what observed in murine fibroblast and human cancer cell lines, transcriptionally active regions of the genome may be preferred targets of retroviral vectors in human primary T lymphocytes. At the same time, our observations show that the resulting integration events are compatible with long-term, event-free in vivo survival of gene-modified cells in clinical settings.

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Stress responses as determinants of antimicrobial resistance in Pseudomonas aeruginosa: multidrug efflux and more

Canadian Journal of Microbiology ◽

10.1139/cjm-2014-0666 ◽

2014 ◽

Vol 60 (12) ◽

pp. 783-791 ◽

Cited By ~ 27

Author(s):

Keith Poole

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Resistance ◽

Environmental Stress ◽

Stress Responses ◽

Acquired Resistance ◽

Resistance Mechanisms ◽

Resistant Organism ◽

Multidrug Efflux ◽

Resistance Development ◽

Endogenous Genes

Pseudomonas aeruginosa is a notoriously antimicrobial-resistant organism that is increasingly refractory to antimicrobial chemotherapy. While the usual array of acquired resistance mechanisms contribute to resistance development in this organism a multitude of endogenous genes also play a role. These include a variety of multidrug efflux loci that contribute to both intrinsic and acquired antimicrobial resistance. Despite their roles in resistance, however, it is clear that these efflux systems function in more than just antimicrobial efflux. Indeed, recent data indicate that they are recruited in response to environmental stress and, therefore, function as components of the organism’s stress responses. In fact, a number of endogenous resistance-promoting genes are linked to environmental stress, functioning as part of known stress responses or recruited in response to a variety of environmental stress stimuli. Stress responses are, thus, important determinants of antimicrobial resistance in P. aeruginosa. As such, they represent possible therapeutic targets in countering antimicrobial resistance in this organism.

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Mechanisms leading to in vivo ceftolozane/tazobactam resistance development during the treatment of infections caused by MDR Pseudomonas aeruginosa

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkx424 ◽

2017 ◽

Vol 73 (3) ◽

pp. 658-663 ◽

Cited By ~ 56

Author(s):

Pablo A Fraile-Ribot ◽

Gabriel Cabot ◽

Xavier Mulet ◽

Leonor Periañez ◽

M Luisa Martín-Pena ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Resistance Development

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Copper(ii) complexes with aromatic nitrogen-containing heterocycles as effective inhibitors of quorum sensing activity in Pseudomonas aeruginosa

RSC Advances ◽

10.1039/c6ra19902j ◽

2016 ◽

Vol 6 (89) ◽

pp. 86695-86709 ◽

Cited By ~ 16

Author(s):

Biljana Đ. Glišić ◽

Ivana Aleksic ◽

Peter Comba ◽

Hubert Wadepohl ◽

Tatjana Ilic-Tomic ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Bacterial Growth ◽

Lower Risk ◽

Pronounced Effect ◽

Resistance Development ◽

New Class ◽

Quorum Sensing Inhibitors

Copper(ii) complexes with aromatic nitrogen-containing heterocycles are a new class of quorum sensing inhibitors that attenuate virulence without a pronounced effect on the bacterial growth, thus offering a lower risk for resistance development.

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Mechanisms of Antimicrobial Resistance in Pseudomonas aeruginosa and a Multi-Pronged Approach to Combat its Infection in Veterinary Science and Public Health: A Review

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1801 ◽

2021 ◽

Vol 26 (01) ◽

pp. 1-8

Author(s):

Bahar-e- Mustafa

Keyword(s):

Public Health ◽

Pseudomonas Aeruginosa ◽

Antibiotic Resistance ◽

Molecular Mechanisms ◽

Resistance Mechanisms ◽

Modern Technology ◽

Multi Drug Resistance ◽

Resistance Development ◽

Over Expression ◽

Permeability Modification

Pseudomonas aeruginosa is one of the most important nosocomial pathogens associated with a variety of medical and veterinary infections and therefore, it presents a major public health threat. Different classes of antibiotics are being used to treat its infections which are increasing selective pressure to multi-drug resistance development. Resistance to antibiotics in P. aeruginosa is due to many of the common and unique mechanisms which include: reducing membrane permeability, modification or inactivation of antibiotics, alteration of enzymes, modification of target sites and over-expression of efflux systems. Over or under expression of the genes of porin channels and components of efflux systems play a major role in the resistance mechanisms of P. aeruginosa. To overcome the problem of the emergence of antibiotic resistance, many new strategies are being employed to control infections caused by P. aeruginosa. These include the use of herbs/medicinal plants and phage therapy. With the advent of modern technology, the molecular mechanisms of these alternative therapies are being elucidated and may be used in future to treat P. aeruginosa infections in humans and veterinary clinics. This review thus highlights the mechanisms of antibiotic resistance of P. aeruginosa against the commonly used antimicrobials and also some alternative strategies to control P. aeruginosa infection. © 2021 Friends Science Publishers

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