scholarly journals In Vivo-Induced Genes in Pseudomonas aeruginosa

2000 ◽  
Vol 68 (4) ◽  
pp. 2359-2362 ◽  
Author(s):  
Martin Handfield ◽  
Dario E. Lehoux ◽  
François Sanschagrin ◽  
Michael J. Mahan ◽  
Donald E. Woods ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Chronic Infection ◽  
Iron Acquisition ◽  
Systemic Infection ◽  
Lung Model ◽  
Rat Lung ◽  
Reading Frame ◽  
Sequence Identity ◽  
Induced Genes

ABSTRACT In vivo expression technology was used for testingPseudomonas aeruginosa in the rat lung model of chronic infection and in a mouse model of systemic infection. Three of the eight ivi proteins found showed sequence identity to known virulence factors involved in iron acquisition via an open reading frame (called pvdI) implicated in pyoverdine biosynthesis, membrane biogenesis (FtsY), and adhesion (Hag2).

scholarly journals Staphylococcus aureus Serves as an Iron Source for Pseudomonas aeruginosa during In Vivo Coculture

2005 ◽  
Vol 187 (2) ◽  
pp. 554-566 ◽  
Author(s):  
Lauren M. Mashburn ◽  
Amy M. Jett ◽  
Darrin R. Akins ◽  
Marvin Whiteley
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Pathogenic Bacteria ◽  
Iron Acquisition ◽  
Low Oxygen ◽  
Dialysis Membrane ◽  
Opportunistic Human Pathogen ◽  
The Impact

ABSTRACT Pseudomonas aeruginosa is a gram-negative opportunistic human pathogen often infecting the lungs of individuals with the heritable disease cystic fibrosis and the peritoneum of individuals undergoing continuous ambulatory peritoneal dialysis. Often these infections are not caused by colonization with P. aeruginosa alone but instead by a consortium of pathogenic bacteria. Little is known about growth and persistence of P. aeruginosa in vivo, and less is known about the impact of coinfecting bacteria on P. aeruginosa pathogenesis and physiology. In this study, a rat dialysis membrane peritoneal model was used to evaluate the in vivo transcriptome of P. aeruginosa in monoculture and in coculture with Staphylococcus aureus. Monoculture results indicate that approximately 5% of all P. aeruginosa genes are differentially regulated during growth in vivo compared to in vitro controls. Included in this analysis are genes important for iron acquisition and growth in low-oxygen environments. The presence of S. aureus caused decreased transcription of P. aeruginosa iron-regulated genes during in vivo coculture, indicating that the presence of S. aureus increases usable iron for P. aeruginosa in this environment. We propose a model where P. aeruginosa lyses S. aureus and uses released iron for growth in low-iron environments.

scholarly journals Correction to: Drug Absorption Parameters Obtained Using the Isolated Perfused Rat Lung Model Are Predictive of Rat In Vivo Lung Absorption

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Johanna Eriksson ◽  
Erik Sjögren ◽  
Hans Lennernäs ◽  
Helena Thörn
Keyword(s):  
Drug Absorption ◽  
Lung Model ◽  
Rat Lung

scholarly journals Pulmonary Metabolism of Substrates for Key Drug-Metabolizing Enzymes by Human Alveolar Type II Cells, Human and Rat Lung Microsomes, and the Isolated Perfused Rat Lung Model

Pharmaceutics ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 117
Author(s):  
Katarina Rubin ◽  
Pär Ewing ◽  
Erica Bäckström ◽  
Anna Abrahamsson ◽  
Britta Bonn ◽  
...  
Keyword(s):  
Human Lung ◽  
Limit Of Detection ◽  
Lung Model ◽  
Alveolar Type ◽  
Metabolic Clearance ◽  
Drug Metabolizing Enzymes ◽  
Type Ii ◽  
Rat Lung ◽  
Metabolizing Enzymes

Significant pulmonary metabolism of inhaled drugs could have drug safety implications or influence pharmacological effectiveness. To study this in vitro, lung microsomes or S9 are often employed. Here, we have determined if rat and human lung microsomes are fit for purpose or whether it is better to use specific cells where drug-metabolizing enzymes are concentrated, such as alveolar type II (ATII) cells. Activities for major hepatic and pulmonary human drug-metabolizing enzymes are assessed and the data contextualized towards an in vivo setting using an ex vivo isolated perfused rat lung model. Very low rates of metabolism are observed in incubations with human ATII cells when compared to isolated hepatocytes and fewer of the substrates are found to be metabolized when compared to human lung microsomal incubations. Reactions selective for flavin-containing monooxygenases (FMOs), CYP1B1, CYP2C9, CYP2J2, and CYP3A4 all show significant rates in human lung microsomal incubations, but all activities are higher when rat lung microsomes are used. The work also demonstrates that a lung microsomal intrinsic clearance value towards the lower limit of detection for this parameter (3 µL/min/mg protein) results in a very low level of pulmonary metabolic clearance during the absorption period, for a drug dosed into the lung in vivo.

scholarly journals Requirement of the Pseudomonas aeruginosa tonB Gene for High-Affinity Iron Acquisition and Infection

2000 ◽  
Vol 68 (8) ◽  
pp. 4498-4504 ◽  
Author(s):  
Hiroyuki Takase ◽  
Hironobu Nitanai ◽  
Kazuki Hoshino ◽  
Tsuyoshi Otani
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Iron Acquisition ◽  
Animal Experiments ◽  
Strain Pao1 ◽  
Free Iron ◽  
High Affinity ◽  
Tonb Protein ◽  
In Vivo Growth ◽  
Immunosuppressed Mice

ABSTRACT To investigate the contribution of the TonB protein to high-affinity iron acquisition in Pseudomonas aeruginosa, we constructed tonB-inactivated mutants from strain PAO1 and its derivative deficient in producing the siderophores pyoverdin and pyochelin. The tonB mutants could not grow in a free-iron-restricted medium prepared by apotransferrin addition, even though the medium was supplemented with each purified siderophore or with a heme source (hemoglobin or hemin). The tonBinactivation was shown to make P. aeruginosa unable to acquire iron from the transferrin with either siderophore. Introduction of a plasmid carrying the intact tonB gene restored growth of the tonB mutant of PAO1 in the free-iron-restricted medium without any supplements and restored growth of thetonB mutant of the siderophore-deficient derivative in the medium supplemented with pyoverdin, pyochelin, hemoglobin, or hemin. In addition, animal experiments showed that, in contrast to PAO1, thetonB mutant of PAO1 could not grow in vivo, such as in the muscles and lungs of immunosuppressed mice, and could not kill any of the animals. The in vivo growth ability and lethal virulence were also restored by introduction of the tonB-carrying plasmid in the tonB mutant. These results indicate clearly that the intact tonB gene—and, therefore, the TonB protein encoded by it—is essential for iron acquisition mediated by pyoverdin and pyochelin and via heme uptake in P. aeruginosa and suggest that the TonB-dependent iron acquisition may be essential for P. aeruginosa to infect the animal host.

scholarly journals Filamentous Bacteriophage Produced by Pseudomonas aeruginosa Alters the Inflammatory Response and Promotes Noninvasive Infection In Vivo

2016 ◽  
Vol 85 (1) ◽  
Author(s):  
Patrick R. Secor ◽  
Lia A. Michaels ◽  
Kate S. Smigiel ◽  
Maryam G. Rohani ◽  
Laura K. Jennings ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inflammatory Response ◽  
Chronic Infection ◽  
Bacterial Invasion ◽  
Airway Epithelial ◽  
Content Type ◽  
Epithelial Cultures ◽  
Opportunistic Human Pathogen

ABSTRACT Pseudomonas aeruginosa is an important opportunistic human pathogen that lives in biofilm-like cell aggregates at sites of chronic infection, such as those that occur in the lungs of patients with cystic fibrosis and nonhealing ulcers. During growth in a biofilm, P. aeruginosa dramatically increases the production of filamentous Pf bacteriophage (Pf phage). Previous work indicated that when in vivo Pf phage production was inhibited, P. aeruginosa was less virulent. However, it is not clear how the production of abundant quantities of Pf phage similar to those produced by biofilms under in vitro conditions affects pathogenesis. Here, using a murine pneumonia model, we show that the production of biofilm-relevant amounts of Pf phage prevents the dissemination of P. aeruginosa from the lung. Furthermore, filamentous phage promoted bacterial adhesion to mucin and inhibited bacterial invasion of airway epithelial cultures, suggesting that Pf phage traps P. aeruginosa within the lung. The in vivo production of Pf phage was also associated with reduced lung injury, reduced neutrophil recruitment, and lower cytokine levels. Additionally, when producing Pf phage, P. aeruginosa was less prone to phagocytosis by macrophages than bacteria not producing Pf phage. Collectively, these data suggest that filamentous Pf phage alters the progression of the inflammatory response and promotes phenotypes typically associated with chronic infection.

scholarly journals Systemic Infection by Pseudomonas aeruginosa in a Dog

2016 ◽  
Vol 44 (1) ◽  
pp. 5
Author(s):  
Layze Cilmara Alves Da Silva ◽  
Danielle Aluska Do Nascimento Pessoa ◽  
Lisanka Ângelo Maia ◽  
Rodrigo Antonio Torres Matos ◽  
Meire Maia da Silva Macêdo
Keyword(s):  
Internal Medicine ◽  
Pseudomonas Aeruginosa ◽  
Veterinary Medicine ◽  
Acquired Resistance ◽  
Systemic Infection ◽  
Care Needs ◽  
Cutaneous Lesions ◽  
Disk Diffusion Test

Background: Pseudomonas aeruginosa is an important pathogen frequently associated with nosocomial infections affecting mainly immunosuppressed patients. In Veterinary Medicine, infections caused by P. aeruginosa are becoming increasingly frequent; infections are related to intrinsic or acquired resistance mechanisms, which limit the choice of effective agents.Case: This study describes the case of a four-month-old male Pitt Bull dog treated at the Small Animal Internal Medicine service of the Veterinary Hospital at the Health and Rural Technology Center of Federal University of Campina Grande, Patos/Paraíba. The patient presented with apathy, inappetence, moderate dehydration, tachypnea, tachycardia, hyperther­mia, pale mucosae, small lesions in the pelvic limbs, with edema and subsequent widespread petechiae. Treatment with intravenous fluid therapy using 0.9% NaCl with B-complex vitamins, and 20 mg/kg cephalexin every 12 h was established. The patient did not respond well to treatment, and died two days later. Necropsy was performed at the Veterinary Pathology sector of the Hospital and histopathological findings revealed focally extensive areas of necrosis associated to myriads of bacteria and mild mononuclear inflammatory infiltrates in the liver, heart and kidneys. Secretions and organ fragments were submitted to the Microbiology Laboratory of the same institution, which identified a systemic bacterial infection caused by P. aeruginosa. In vitro bacterial susceptibility to 15 different antimicrobials was assessed using the Bauer-Kirby disk diffusion test in Mueller Hinton agar. The agent exhibited multiple resistance to enrofloxacin, cephalexin, ceftiofur, gentamicin, imipenem, kanamycin, cephalothin, norfloxacin, amoxicillin, polymyxin B, ampicillin, tetracycline, and penicillin. It was sensitive to amikacin and neomycin only. Phenotypic detection was performed via disk approximation test (D-test) established by the Clinical and Laboratory Standard Institute (CLSI), which showed metallo-beta-lactamase (MBLs)-producing bacteria.Discussion: Clinical-pathological and microbiological aspects confirmed a systemic infection by P. aeruginosa characterized by yellowish nodular lesions and occasional hemorrhage, associated with myriads of bacteria in the lumen of the vessels in multiple organs. The agent was probably disseminated hematogenously, and it is likely that the cutaneous lesions in the pelvic limbs were the entry point. Treatment using cephalexin proved to be inefficient for the animal of the present study, which may have been be due to the patient’s immunosuppression and the agent’s natural or acquired resistance to this drug; therefore, special care needs to be taken when using these antibiotics as a preventive measure against the dissemination of gram-negative (MBL)-producing P. aeruginosa. We can conclude that P. aeruginosa may cause systemic infection in dogs. Amikacin and neomycin are the most efficient antimicrobials for the in vitro elimination of the bacteria; however, other studies on the use of these drugs in vivo are needed. Considering the occurrence of resistance to multiple antimicrobials and the production of MBLs observed in this study, it is important to monitor P. aeruginosa through phenotypical and antimicrobial susceptibility tests to verify its level of resistance in diseases in Veterinary Medicine.Keywords: microbiological, internal medicine, infections, Veterinary Medicine.

scholarly journals Antibodies Against Pseudomonas aeruginosa Alkaline Protease Directly Enhance Disruption of Neutrophil Extracellular Traps Mediated by This Enzyme

2021 ◽  
Vol 12 ◽  
Author(s):  
Chendi Jing ◽  
Chenghua Liu ◽  
Yu Liu ◽  
Ruli Feng ◽  
Run Cao ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Alkaline Protease ◽  
Chronic Infection ◽  
Active Sites ◽  
Neutrophil Extracellular Traps ◽  
Lung Infection ◽  
Bacterial Burden ◽  
Extracellular Traps

Extracellular traps released by neutrophils (NETs) are essential for the clearance of Pseudomonas aeruginosa. Alkaline protease (AprA) secreted by P. aeruginosa negatively correlates with clinical improvement. Moreover, anti-AprA in patients with cystic fibrosis (CF) can help identify patients with aggressive forms of chronic infection. However, the mechanism underlying the clinical outcomes remains unclear. We demonstrated that aprA deficiency in P. aeruginosa decreased the bacterial burden and reduced lung infection. AprA degraded NET components in vitro and in vivo but did not affect NET formation. Importantly, antibodies induced by AprA acted as an agonist and directly enhanced the degrading activities of AprA. Moreover, antisera from patients with P. aeruginosa infection exhibited antibody-dependent enhancement (ADE) similar to that of the antibodies we prepared. Our further investigations showed that the interaction between AprA and the specific antibodies might make the enzyme active sites better exposed, and subsequently enhance the recognition of substrates and accelerate the degradation. Our findings revealed that AprA secreted by P. aeruginosa may aggravate infection by destroying formed NETs, an effect that was further enhanced by its antibodies.

scholarly journals Adaptation-Based Resistance to Siderophore-Conjugated Antibacterial Agents by Pseudomonas aeruginosa

2013 ◽  
Vol 57 (9) ◽  
pp. 4197-4207 ◽  
Author(s):  
Andrew P. Tomaras ◽  
Jared L. Crandon ◽  
Craig J. McPherson ◽  
Mary Anne Banevicius ◽  
Steven M. Finegan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Agents ◽  
Iron Acquisition ◽  
Content Type ◽  
Multiple Strains ◽  
Resistance Rates ◽  
Assay Conditions

ABSTRACTMultidrug resistance in Gram-negative bacteria has become so threatening to human health that new antibacterial platforms are desperately needed to combat these deadly infections. The concept of siderophore conjugation, which facilitates compound uptake across the outer membrane by hijacking bacterial iron acquisition systems, has received significant attention in recent years. While standardin vitroMIC and resistance frequency methods demonstrate that these compounds are potent, broad-spectrum antibacterial agents whose activity should not be threatened by unacceptably high spontaneous resistance rates, recapitulation of these results in animal models can prove unreliable, partially because of the differences in iron availability in these different methods. Here, we describe the characterization of MB-1, a novel siderophore-conjugated monobactam that demonstrates excellentin vitroactivity againstPseudomonas aeruginosawhen tested using standard assay conditions. Unfortunately, thein vitrofindings did not correlate with thein vivoresults we obtained, as multiple strains were not effectively treated by MB-1 despite having low MICs. To address this, we also describe the development of newin vitroassays that were predictive of efficacy in mouse models, and we provide evidence that competition with native siderophores could contribute to the recalcitrance of someP. aeruginosaisolatesin vivo.

scholarly journals In Vivo Evidence of Pseudomonas aeruginosa Nutrient Acquisition and Pathogenesis in the Lungs of Cystic Fibrosis Patients

2007 ◽  
Vol 75 (11) ◽  
pp. 5313-5324 ◽  
Author(s):  
Mike S. Son ◽  
Wallace J. Matthews ◽  
Yun Kang ◽  
David T. Nguyen ◽  
Tung T. Hoang
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Drug Resistance ◽  
Chronic Infection ◽  
Natural Infection ◽  
Lung Surfactant ◽  
Nutrient Utilization ◽  
Lipid Molecule ◽  
Nutrient Sources

ABSTRACT One of the hallmarks of Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients is very-high-cell-density (HCD) replication in the lung, allowing this bacterium to induce virulence controlled by the quorum-sensing systems. However, the nutrient sources sustaining HCD replication in this chronic infection are largely unknown. Here, we performed microarray studies of P. aeruginosa directly isolated from the lungs of CF patients to demonstrate its metabolic capability and virulence in vivo. In vivo microarray data, confirmed by real-time reverse transcription-PCR, indicated that the P. aeruginosa population expressed several genes for virulence, drug resistance, and utilization of multiple nutrient sources (lung surfactant lipids and amino acids) contributing to HCD replication. The most abundant lung surfactant lipid molecule, phosphatidylcholine (PC), induces key genes of P. aeruginosa pertinent to PC degradation in vitro as well as in vivo within the lungs of CF patients. The results support recent research indicating that P. aeruginosa exists in the lungs of CF patients as a diverse population with full virulence potential. The data also indicate that there is deregulation of several pathways, suggesting that there is in vivo evolution by deregulation of a large portion of the transcriptome during chronic infection in CF patients. To our knowledge, this is the first in vivo transcriptome analysis of P. aeruginosa in a natural infection in CF patients, and the results indicate several important aspects of P. aeruginosa pathogenesis, drug resistance, nutrient utilization, and general metabolism within the lungs of CF patients.

scholarly journals Tropomyosin is essential in yeast, yet the TPM1 and TPM2 products perform distinct functions.

1995 ◽  
Vol 128 (3) ◽  
pp. 383-392 ◽  
Author(s):  
B Drees ◽  
C Brown ◽  
B G Barrell ◽  
A Bretscher
Keyword(s):  
Sequence Analysis ◽  
Wild Type ◽  
Purification And Characterization ◽  
Reading Frame ◽  
Over Expression ◽  
Sequence Identity ◽  
Bona Fide ◽  
Essential Function

Sequence analysis of chromosome IX of Saccharomyces cerevisiae revealed an open reading frame of 166 residues, designated TPM2, having 64.5% sequence identity to TPM1, that encodes the major form of tropomyosin in yeast. Purification and characterization of Tpm2p revealed a protein with the characteristics of a bona fide tropomyosin; it is present in vivo at about one sixth the abundance of Tpm1p. Biochemical and sequence analysis indicates that Tpm2p spans four actin monomers along a filament, whereas Tpmlp spans five. Despite its shorter length, Tpm2p can compete with Tpm1p for binding to F-actin. Over-expression of Tpm2p in vivo alters the axial budding of haploids to a bipolar pattern, and this can be partially suppressed by co-over-expression of Tpm1p. This suggests distinct functions for the two tropomyosins, and indicates that the ratio between them is important for correct morphogenesis. Loss of Tpm2p has no detectable phenotype in otherwise wild type cells, but is lethal in combination with tpm1 delta. Over-expression of Tpm2p does not suppress the growth or cell surface targeting defects associated with tpm1 delta, so the two tropomyosins must perform an essential function, yet are not functionally interchangeable. S. cerevisiae therefore provides a simple system for the study of two tropomyosins having distinct yet overlapping functions.

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