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Hofer RN, Lin A, House BC, Purvis CN, Harris BJ, Symes SJK, Giles DK. Exogenous polyunsaturated fatty acids (PUFAs) influence permeability, antimicrobial peptide resistance, biofilm formation and membrane phospholipid structure in an A-layer and non-A-layer strain of Aeromonas salmonicida. J Fish Dis 2023; 46:31-45. [PMID: 36088584 DOI: 10.1111/jfd.13715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
Aeromonas salmonicida is a Gram-negative bacterium that can infect a wide host range of fish populations, including salmonids and non-salmonids as well as freshwater and marine life. Some strains of A. salmonicida cause the disease furunculosis, which can cause lethargy, intestinal inflammation, ulcers, haemorrhaging and death. The infection is spread through fish-to-fish contact, and the presence of infection can have devastating effects on cultivated fish populations. The purpose of this study was to explore the ability of non-A-layer and A-layer A. salmonicida strains to incorporate polyunsaturated fatty acids (PUFAs) into their lipid profile and test the phenotypic effects thereof. Lipids were extracted from PUFA-exposed cultures and analysed for lipid modification by thin-layer chromatography and ultraperformance liquid chromatography-mass spectrometry, showing A. salmonicida, regardless of A-layer, capable of incorporating all seven of the PUFAs studied. Phenotypic effects were determined through the use of assays that tested for biofilm formation, membrane permeability and cyclic peptide susceptibility. Temperature-dependent effects on biofilm formation were observed, and PUFA exposure showed significant (p < .001) increases in membrane permeability as tested by the uptake of the hydrophobic compounds crystal violet and ethidium bromide. Additionally, some PUFAs elicited modest protection and vulnerability against the membrane-targeting cyclic peptides polymyxin B (PMB) and colistin. The diverse, strain-specific responses to exogenous PUFAs may allude to evolved adaptive strategies that enhance survival, persistence and virulence of non-pathogenic and pathogenic members of bacteria that oscillate between environmental and fish host niches.
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Affiliation(s)
- Rachel N Hofer
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - Allen Lin
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - Benjamin C House
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - Christopher N Purvis
- Department of Chemical Engineering, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - Bradley J Harris
- Department of Chemical Engineering, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - Steven J K Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
| | - David K Giles
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, USA
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Smith DS, Houck C, Lee A, Simmons TB, Chester ON, Esdaile A, Symes SJK, Giles DK. Polyunsaturated fatty acids cause physiological and behavioral changes in Vibrio alginolyticus and Vibrio fischeri. Microbiologyopen 2021; 10:e1237. [PMID: 34713610 PMCID: PMC8494716 DOI: 10.1002/mbo3.1237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/08/2021] [Indexed: 11/06/2022] Open
Abstract
Vibrio alginolyticus and Vibrio (Aliivibrio) fischeri are Gram-negative bacteria found globally in marine environments. During the past decade, studies have shown that certain Gram-negative bacteria, including Vibrio species (cholerae, parahaemolyticus, and vulnificus) are capable of using exogenous polyunsaturated fatty acids (PUFAs) to modify the phospholipids of their membrane. Moreover, exposure to exogenous PUFAs has been shown to affect certain phenotypes that are important factors of virulence. The purpose of this study was to investigate whether V. alginolyticus and V. fischeri are capable of responding to exogenous PUFAs by remodeling their membrane phospholipids and/or altering behaviors associated with virulence. Thin-layer chromatography (TLC) analyses and ultra-performance liquid chromatography-electrospray ionization mass spectrometry (UPLC/ESI-MS) confirmed incorporation of all PUFAs into membrane phosphatidylglycerol and phosphatidylethanolamine. Several growth phenotypes were identified when individual fatty acids were supplied in minimal media and as sole carbon sources. Interestingly, several PUFAs acids inhibited growth of V. fischeri. Significant alterations to membrane permeability were observed depending on fatty acid supplemented. Strikingly, arachidonic acid (20:4) reduced membrane permeability by approximately 35% in both V. alginolyticus and V. fischeri. Biofilm assays indicated that fatty acid influence was dependent on media composition and temperature. All fatty acids caused decreased swimming motility in V. alginolyticus, while only linoleic acid (18:2) significantly increased swimming motility in V. fischeri. In summary, exogenous fatty acids cause a variety of changes in V. alginolyticus and V. fischeri, thus adding these bacteria to a growing list of Gram-negatives that exhibit versatility in fatty acid utilization and highlighting the potential for environmental PUFAs to influence phenotypes associated with planktonic, beneficial, and pathogenic associations.
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Affiliation(s)
- David S. Smith
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
| | - Carina Houck
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
| | - Allycia Lee
- Department of Chemistry and PhysicsThe University of Tennessee at ChattanoogaChattanoogaTennesseeUSA
| | - Timothy B. Simmons
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
| | - Olivia N. Chester
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
| | - Ayanna Esdaile
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
| | - Steven J. K. Symes
- Department of Chemistry and PhysicsThe University of Tennessee at ChattanoogaChattanoogaTennesseeUSA
| | - David K. Giles
- Department of Biology, Geology, and Environmental ScienceChattanoogaTennesseeUSA
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Herndon JL, Peters RE, Hofer RN, Simmons TB, Symes SJ, Giles DK. Exogenous polyunsaturated fatty acids (PUFAs) promote changes in growth, phospholipid composition, membrane permeability and virulence phenotypes in Escherichia coli. BMC Microbiol 2020; 20:305. [PMID: 33046008 PMCID: PMC7552566 DOI: 10.1186/s12866-020-01988-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/29/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The utilization of exogenous fatty acids by Gram-negative bacteria has been linked to many cellular processes, including fatty acid oxidation for metabolic gain, assimilation into membrane phospholipids, and control of phenotypes associated with virulence. The expanded fatty acid handling capabilities have been demonstrated in several bacteria of medical importance; however, a survey of the polyunsaturated fatty acid responses in the model organism Escherichia coli has not been performed. The current study examined the impacts of exogenous fatty acids on E. coli. RESULTS All PUFAs elicited higher overall growth, with several fatty acids supporting growth as sole carbon sources. Most PUFAs were incorporated into membrane phospholipids as determined by Ultra performance liquid chromatography-mass spectrometry, whereas membrane permeability was variably affected as measured by two separate dye uptake assays. Biofilm formation, swimming motility and antimicrobial peptide resistance were altered in the presence of PUFAs, with arachidonic and docosahexaenoic acids eliciting strong alteration to these phenotypes. CONCLUSIONS The findings herein add E. coli to the growing list of Gram-negative bacteria with broader capabilities for utilizing and responding to exogenous fatty acids. Understanding bacterial responses to PUFAs may lead to microbial behavioral control regimens for disease prevention.
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Affiliation(s)
- Joshua L. Herndon
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN USA
| | - Rachel E. Peters
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN USA
| | - Rachel N. Hofer
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN USA
| | - Timothy B. Simmons
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN USA
| | - Steven J. Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN USA
| | - David K. Giles
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN USA
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Baker LY, Hobby CR, Siv AW, Bible WC, Glennon MS, Anderson DM, Symes SJ, Giles DK. Pseudomonas aeruginosa responds to exogenous polyunsaturated fatty acids (PUFAs) by modifying phospholipid composition, membrane permeability, and phenotypes associated with virulence. BMC Microbiol 2018; 18:117. [PMID: 30217149 PMCID: PMC6137939 DOI: 10.1186/s12866-018-1259-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 09/05/2018] [Indexed: 12/20/2022] Open
Abstract
Background Pseudomonas aeruginosa, a common opportunistic pathogen, is known to cause infections in a variety of compromised human tissues. An emerging mechanism for microbial survival is the incorporation of exogenous fatty acids to alter the cell’s membrane phospholipid profile. With these findings, we show that exogenous fatty acid exposure leads to changes in bacterial membrane phospholipid structure, membrane permeability, virulence phenotypes and consequent stress responses that may influence survival and persistence of Pseudomonas aeruginosa. Results Thin-layer chromatography and ultra performance liquid chromatography / ESI-mass spectrometry indicated alteration of bacterial phospholipid profiles following growth in the presence of polyunsaturated fatty acids (PUFAs) (ranging in carbon length and unsaturation). The exogenously supplied fatty acids were incorporated into the major bacterial phospholipids phosphatidylethanolamine and phosphatidylglycerol. The incorporation of fatty acids increased membrane permeability as judged by both accumulation and exclusion of ethidium bromide. Individual fatty acids were identified as modifying resistance to the cyclic peptide antibiotics polymyxin B and colistin, but not the beta-lactam imipenem. Biofilm formation was increased by several PUFAs and significant fluctuations in swimming motility were observed. Conclusions Our results emphasize the relevance and complexity of exogenous fatty acids in the membrane physiology and pathobiology of a medically important pathogen. P. aeruginosa exhibits versatility with regard to utilization of and response to exogenous fatty acids, perhaps revealing potential strategies for prevention and control of infection. Electronic supplementary material The online version of this article (10.1186/s12866-018-1259-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lyssa Y Baker
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Chelsea R Hobby
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Andrew W Siv
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - William C Bible
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Michael S Glennon
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Derek M Anderson
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Steven J Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - David K Giles
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA.
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Hobby CR, Herndon JL, Morrow CA, Peters RE, Symes SJK, Giles DK. Exogenous fatty acids alter phospholipid composition, membrane permeability, capacity for biofilm formation, and antimicrobial peptide susceptibility in Klebsiella pneumoniae. Microbiologyopen 2018; 8:e00635. [PMID: 29701307 PMCID: PMC6391273 DOI: 10.1002/mbo3.635] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/20/2018] [Accepted: 03/05/2018] [Indexed: 12/15/2022] Open
Abstract
Klebsiella pneumoniae represents a major threat to human health due to a combination of its nosocomial emergence and a propensity for acquiring antibiotic resistance. Dissemination of the bacteria from its native intestinal location creates severe, complicated infections that are particularly problematic in healthcare settings. Thus, there is an urgency for identifying novel treatment regimens as the incidence of highly antibiotic‐resistant bacteria rises. Recent findings have highlighted the ability of some Gram‐negative bacteria to utilize exogenous fatty acids in ways that modify membrane phospholipids and influence virulence phenotypes, such as biofilm formation and antibiotic resistance. This study explores the ability of K. pneumoniae to assimilate and respond to exogenous fatty acids. The combination of thin‐layer chromatography liquid chromatography‐mass spectrometry confirmed adoption of numerous exogenous polyunsaturated fatty acids (PUFAs) into the phospholipid species of K. pneumoniae. Membrane permeability was variably affected as determined by two dye uptake assays. Furthermore, the availability of many PUFAs lowered the MICs to the antimicrobial peptides polymyxin B and colistin. Biofilm formation was significantly affected depending upon the supplemented fatty acid.
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Affiliation(s)
- Chelsea R Hobby
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Joshua L Herndon
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Colton A Morrow
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Rachel E Peters
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Steven J K Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - David K Giles
- Department of Biology, Geology, and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
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Spratt HG, Levine D, Bage J, Giles DK, Collier AG. Topical lotions utilized in outpatient rehabilitation clinics as a potential source of bacterial contamination. Physiother Theory Pract 2018; 35:163-170. [PMID: 29482428 DOI: 10.1080/09593985.2018.1441935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Soft tissue mobilization and massage requiring lotions or creams are commonly used interventions in outpatient rehabilitation clinics. For at least 50 years hand creams used in healthcare settings have been found to be contaminated by bacteria. The purpose of this study was to determine the current state of bacterial contamination of lotions used in clinics and to determine the efficacy of lotion preservatives to kill bacteria. Unopened containers of lotions were studied, along with 81 lotion containers used in 22 outpatient clinics in southeast Tennessee and northwest Georgia. Three sites on each container were sampled using sterile swabs. At a microbiology lab, bacterial growth media was inoculated and incubated. Of the 81 containers sampled, 16 supported bacterial growth (19.8%). Container threads displayed the highest contamination compared with other container locations (p < 0.01). No bacteria were found in unopened lotion containers, although when challenged with live bacterial cultures lotion preservatives did not kill bacteria tested. Enrichment cultures using lotions studied here supported the growth of several bacterial species. These findings suggest the need for standardized protocols to help reduce potential healthcare-associated infections due to use of lotions. Improved efficacy of preservatives added to lotions should be a priority.
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Affiliation(s)
- Henry G Spratt
- a Department of Biology, Geology, and Environmental Science , University of Tennessee at Chattanooga , Chattanooga , TN , USA
| | - David Levine
- b Department of Physical Therapy , University of Tennessee at Chattanooga , Chattanooga , TN , USA
| | - Julie Bage
- b Department of Physical Therapy , University of Tennessee at Chattanooga , Chattanooga , TN , USA
| | - David K Giles
- a Department of Biology, Geology, and Environmental Science , University of Tennessee at Chattanooga , Chattanooga , TN , USA
| | - A Grace Collier
- a Department of Biology, Geology, and Environmental Science , University of Tennessee at Chattanooga , Chattanooga , TN , USA
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Eder AE, Munir SA, Hobby CR, Anderson DM, Herndon JL, Siv AW, Symes SJK, Giles DK. Exogenous polyunsaturated fatty acids (PUFAs) alter phospholipid composition, membrane permeability, biofilm formation and motility in Acinetobacter baumannii. Microbiology (Reading) 2017; 163:1626-1636. [PMID: 29058654 DOI: 10.1099/mic.0.000556] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Acinetobacter baumannii is a ubiquitous multidrug-resistant bacteria that is found on a variety of surfaces, including skin, hair and soil. During the past decade, A. baumannii has emerged as a significant cause of nosocomial infections in the United States. Recent studies have highlighted the ability of some bacteria to utilize a wide variety of fatty acids as a membrane remodelling strategy. Considering this, we hypothesized that fatty acids may have an effect on the emerging pathogen A. baumannii. Thin-layer chromatography indicated structural alterations to major phospholipids. Liquid chromatography/mass spectrometry confirmed the assimilation of numerous exogenous polyunsaturated fatty acids (PUFAs) into the phospholipid species of A. baumannii. The incorporation of fatty acids affected several bacterial phenotypes, including membrane permeability, biofilm formation, surface motility and antimicrobial peptide resistance.
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Affiliation(s)
- Adrianna E Eder
- Department of Biology, Geology and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Saba A Munir
- Department of Biology, Geology and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Chelsea R Hobby
- Department of Biology, Geology and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Derek M Anderson
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Joshua L Herndon
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Andrew W Siv
- Department of Biology, Geology and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Steven J K Symes
- Department of Chemistry and Physics, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - David K Giles
- Department of Biology, Geology and Environmental Science, The University of Tennessee at Chattanooga, Chattanooga, TN, USA
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Madsen JA, Xu H, Robinson MR, Horton AP, Shaw JB, Giles DK, Kaoud TS, Dalby KN, Trent MS, Brodbelt JS. High-throughput database search and large-scale negative polarity liquid chromatography-tandem mass spectrometry with ultraviolet photodissociation for complex proteomic samples. Mol Cell Proteomics 2013; 12:2604-14. [PMID: 23695934 DOI: 10.1074/mcp.o113.028258] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The use of ultraviolet photodissociation (UVPD) for the activation and dissociation of peptide anions is evaluated for broader coverage of the proteome. To facilitate interpretation and assignment of the resulting UVPD mass spectra of peptide anions, the MassMatrix database search algorithm was modified to allow automated analysis of negative polarity MS/MS spectra. The new UVPD algorithms were developed based on the MassMatrix database search engine by adding specific fragmentation pathways for UVPD. The new UVPD fragmentation pathways in MassMatrix were rigorously and statistically optimized using two large data sets with high mass accuracy and high mass resolution for both MS(1) and MS(2) data acquired on an Orbitrap mass spectrometer for complex Halobacterium and HeLa proteome samples. Negative mode UVPD led to the identification of 3663 and 2350 peptides for the Halo and HeLa tryptic digests, respectively, corresponding to 655 and 645 peptides that were unique when compared with electron transfer dissociation (ETD), higher energy collision-induced dissociation, and collision-induced dissociation results for the same digests analyzed in the positive mode. In sum, 805 and 619 proteins were identified via UVPD for the Halobacterium and HeLa samples, respectively, with 49 and 50 unique proteins identified in contrast to the more conventional MS/MS methods. The algorithm also features automated charge determination for low mass accuracy data, precursor filtering (including intact charge-reduced peaks), and the ability to combine both positive and negative MS/MS spectra into a single search, and it is freely open to the public. The accuracy and specificity of the MassMatrix UVPD search algorithm was also assessed for low resolution, low mass accuracy data on a linear ion trap. Analysis of a known mixture of three mitogen-activated kinases yielded similar sequence coverage percentages for UVPD of peptide anions versus conventional collision-induced dissociation of peptide cations, and when these methods were combined into a single search, an increase of up to 13% sequence coverage was observed for the kinases. The ability to sequence peptide anions and cations in alternating scans in the same chromatographic run was also demonstrated. Because ETD has a significant bias toward identifying highly basic peptides, negative UVPD was used to improve the identification of the more acidic peptides in conjunction with positive ETD for the more basic species. In this case, tryptic peptides from the cytosolic section of HeLa cells were analyzed by polarity switching nanoLC-MS/MS utilizing ETD for cation sequencing and UVPD for anion sequencing. Relative to searching using ETD alone, positive/negative polarity switching significantly improved sequence coverages across identified proteins, resulting in a 33% increase in unique peptide identifications and more than twice the number of peptide spectral matches.
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Affiliation(s)
- James A Madsen
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712, USA
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Maue AC, Mohawk KL, Giles DK, Poly F, Ewing CP, Jiao Y, Lee G, Ma Z, Monteiro MA, Hill CL, Ferderber JS, Porter CK, Trent MS, Guerry P. The polysaccharide capsule of Campylobacter jejuni modulates the host immune response. Infect Immun 2013; 81:665-72. [PMID: 23250948 PMCID: PMC3584872 DOI: 10.1128/iai.01008-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/05/2012] [Indexed: 12/22/2022] Open
Abstract
Campylobacter jejuni is a major cause of bacterial diarrheal disease worldwide. The organism is characterized by a diversity of polysaccharide structures, including a polysaccharide capsule. Most C. jejuni capsules are known to be decorated nonstoichiometrically with methyl phosphoramidate (MeOPN). The capsule of C. jejuni 81-176 has been shown to be required for serum resistance, but here we show that an encapsulated mutant lacking the MeOPN modification, an mpnC mutant, was equally as sensitive to serum killing as the nonencapsulated mutant. A nonencapsulated mutant, a kpsM mutant, exhibited significantly reduced colonization compared to that of wild-type 81-176 in a mouse intestinal colonization model, and the mpnC mutant showed an intermediate level of colonization. Both mutants were associated with higher levels of interleukin 17 (IL-17) expression from lamina propria CD4(+) cells than from cells from animals infected with 81-176. In addition, reduced levels of Toll-like receptor 4 (TLR4) and TLR2 activation were observed following in vitro stimulation of human reporter cell lines with the kpsM and mpnC mutants compared to those with wild-type 81-176. The data suggest that the capsule polysaccharide of C. jejuni and the MeOPN modification modulate the host immune response.
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Affiliation(s)
- Alexander C. Maue
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Krystle L. Mohawk
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - David K. Giles
- Department of Biological and Environmental Sciences, University of Tennessee at Chattanooga, Chattagnooga, Tennessee, USA
| | - Frédéric Poly
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Cheryl P. Ewing
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Yuening Jiao
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Ginyoung Lee
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Zuchao Ma
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Mario A. Monteiro
- Department of Chemistry, University of Guelph, Guelph, Ontario, Canada
| | - Christina L. Hill
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Jason S. Ferderber
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Chad K. Porter
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - M. Stephen Trent
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas, USA
| | - Patricia Guerry
- Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
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Cullen TW, Giles DK, Wolf LN, Ecobichon C, Boneca IG, Trent MS. Helicobacter pylori versus the host: remodeling of the bacterial outer membrane is required for survival in the gastric mucosa. PLoS Pathog 2011; 7:e1002454. [PMID: 22216004 PMCID: PMC3245313 DOI: 10.1371/journal.ppat.1002454] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 11/08/2011] [Indexed: 12/11/2022] Open
Abstract
Modification of bacterial surface structures, such as the lipid A portion of lipopolysaccharide (LPS), is used by many pathogenic bacteria to help evade the host innate immune response. Helicobacter pylori, a gram-negative bacterium capable of chronic colonization of the human stomach, modifies its lipid A by removal of phosphate groups from the 1- and 4'-positions of the lipid A backbone. In this study, we identify the enzyme responsible for dephosphorylation of the lipid A 4'-phosphate group in H. pylori, Jhp1487 (LpxF). To ascertain the role these modifications play in the pathogenesis of H. pylori, we created mutants in lpxE (1-phosphatase), lpxF (4'-phosphatase) and a double lpxE/F mutant. Analysis of lipid A isolated from lpxE and lpxF mutants revealed lipid A species with a 1 or 4'-phosphate group, respectively while the double lpxE/F mutant revealed a bis-phosphorylated lipid A. Mutants lacking lpxE, lpxF, or lpxE/F show a 16, 360 and 1020 fold increase in sensitivity to the cationic antimicrobial peptide polymyxin B, respectively. Moreover, a similar loss of resistance is seen against a variety of CAMPs found in the human body including LL37, β-defensin 2, and P-113. Using a fluorescent derivative of polymyxin we demonstrate that, unlike wild type bacteria, polymyxin readily associates with the lpxE/F mutant. Presumably, the increase in the negative charge of H. pylori LPS allows for binding of the peptide to the bacterial surface. Interestingly, the action of LpxE and LpxF was shown to decrease recognition of Helicobacter LPS by the innate immune receptor, Toll-like Receptor 4. Furthermore, lpxE/F mutants were unable to colonize the gastric mucosa of C57BL/6J and C57BL/6J tlr4 -/- mice when compared to wild type H. pylori. Our results demonstrate that dephosphorylation of the lipid A domain of H. pylori LPS by LpxE and LpxF is key to its ability to colonize a mammalian host.
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Affiliation(s)
- Thomas W. Cullen
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, Texas, United States of America
| | - David K. Giles
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Lindsey N. Wolf
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, Texas, United States of America
| | - Chantal Ecobichon
- Institut Pasteur, Group Biology and Genetics of the Bacterial Cell Wall, Paris, France
- INSERM, Groupe Avenir, Paris, France
| | - Ivo G. Boneca
- Institut Pasteur, Group Biology and Genetics of the Bacterial Cell Wall, Paris, France
- INSERM, Groupe Avenir, Paris, France
| | - M. Stephen Trent
- Section of Molecular Genetics and Microbiology, The University of Texas at Austin, Austin, Texas, United States of America
- The Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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Hankins JV, Madsen JA, Giles DK, Childers BM, Klose KE, Brodbelt JS, Trent MS. Elucidation of a novel Vibrio cholerae lipid A secondary hydroxy-acyltransferase and its role in innate immune recognition. Mol Microbiol 2011; 81:1313-29. [PMID: 21752109 PMCID: PMC3178793 DOI: 10.1111/j.1365-2958.2011.07765.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Similar to most Gram-negative bacteria, the outer leaflet of the outer membrane of Vibrio cholerae is comprised of lipopolysaccharide. Previous reports have proposed that V. cholerae serogroups O1 and O139 synthesize structurally different lipid A domains, which anchor lipopolysaccharide within the outer membrane. In the current study, intact lipid A species of V. cholerae O1 and O139 were analysed by mass spectrometry. We demonstrate that V. cholerae serogroups associated with human disease synthesize a similar asymmetrical hexa-acylated lipid A species, bearing a myristate (C14:0) and 3-hydroxylaurate (3-OH C12:0) at the 2'- and 3'-positions respectively. A previous report from our laboratory characterized the V. cholerae LpxL homologue Vc0213, which transfers a C14:0 to the 2'-position of the glucosamine disaccharide. Our current findings identify V. cholerae Vc0212 as a novel lipid A secondary hydroxy-acyltransferase, termed LpxN, responsible for transferring the 3-hydroxylaurate (3-OH C12:0) to the V. cholerae lipid A domain. Importantly, the presence of a 3-hydroxyl group on the 3'-linked secondary acyl chain was found to promote antimicrobial peptide resistance in V. cholerae; however, this functional group was not required for activation of the innate immune response.
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Affiliation(s)
- Jessica V Hankins
- Department of Biochemistry and Molecular Biology, Georgia Health Sciences University, Augusta, GA 30912, USA
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Giles DK, Hankins JV, Guan Z, Trent MS. Remodelling of the Vibrio cholerae membrane by incorporation of exogenous fatty acids from host and aquatic environments. Mol Microbiol 2010; 79:716-28. [PMID: 21255114 DOI: 10.1111/j.1365-2958.2010.07476.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Gram-negative bacteria Vibrio cholerae poses significant public health concerns by causing an acute intestinal infection afflicting millions of people each year. V. cholerae motility, as well as virulence factor expression and outer membrane protein production, has been shown to be affected by bile. The current study examines the effects of bile on V. cholerae phospholipids. Bile exposure caused significant alterations to the phospholipid profile of V. cholerae but not of other enteric pathogens. These changes consisted of a quantitative increase and migratory difference in cardiolipin, decreases in phosphatidylglycerol and phosphatidylethanolamine, and the dramatic appearance of an unknown phospholipid determined to be lyso-phosphatidylethanolamine. Major components of bile were not responsible for the observed changes, but long-chain polyunsaturated fatty acids, which are minor components of bile, were shown to be incorporated into phospholipids of V. cholerae. Although the bile-induced phospholipid profile was independent of the V. cholerae virulence cascade, we identified another relevant environment in which V. cholerae assimilates unique fatty acids into its membrane phospholipids - marine sediment. Our results suggest that Vibrio species possess unique machinery conferring the ability to take up a wider range of exogenous fatty acids than other enteric bacteria.
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Affiliation(s)
- David K Giles
- Section of Molecular Genetics and Microbiology The Institute of Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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Giles DK, Wyrick PB. Trafficking of chlamydial antigens to the endoplasmic reticulum of infected epithelial cells. Microbes Infect 2008; 10:1494-503. [PMID: 18832043 DOI: 10.1016/j.micinf.2008.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2008] [Revised: 08/29/2008] [Accepted: 09/02/2008] [Indexed: 01/02/2023]
Abstract
Confinement of the obligate intracellular bacterium Chlamydia trachomatis to a membrane-bound vacuole, termed an inclusion, within infected epithelial cells neither prevents secretion of chlamydial antigens into the host cytosol nor protects chlamydiae from innate immune detection. However, the details leading to chlamydial antigen presentation are not clear. By immunoelectron microscopy of infected endometrial epithelial cells and in isolated cell secretory compartments, chlamydial major outer membrane protein (MOMP), lipopolysaccharide (LPS) and the inclusion membrane protein A (IncA) were localized to the endoplasmic reticulum (ER) and co-localized with multiple ER markers, but not with markers of the endosomes, lysosomes, Golgi nor mitochondria. Chlamydial LPS was also co-localized with CD1d in the ER. Since the chlamydial antigens, contained in everted inclusion membrane vesicles, were found within the host cell ER, these data raise additional implications for antigen processing by infected uterine epithelial cells for classical and non-classical T cell antigen presentation.
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Affiliation(s)
- David K Giles
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA
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Downey D, Giles DK, Thompson JF. In situ transmissiometer measurements for real-time monitoring of dust discharge during orchard nut harvesting. J Environ Qual 2008; 37:574-581. [PMID: 18396543 DOI: 10.2134/jeq2006.0423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Rapid assessments of operating conditions and field preparation on dust discharge from nut harvesters are needed to guide improved equipment design and grower practices for dust reduction. An industrial opacity sensor, typically used for industrial stack monitoring, was adapted for use on a nut harvester to measure relative dust intensity during nut pick-up operations in almond orchards. Due to the high volume of discharge air and the presence of large debris such as leaves, additional components were coupled with the sensor to enable subsampling of the air. Pre-harvest windrow preparation conditions were evaluated. Results indicated that relative dust intensity decreased by 32% during harvest activities after windrow preparation with proper nut sweeper adjustment. Conventional harvesting results indicated that under typical operating conditions, reducing the separation fan speed could reduce relative dust intensity by 54%. Ground speed also had a strong effect; reducing speed from 4.8 to 2.4 km h(-1) reduced opacity of discharged air by 50%. The measurement system was also mounted on a separate vehicle and used as a tool for comparing modifications in harvest machine designs where direct measurement of discharge may not be feasible due to mechanical constraints. A comparison between a conventional harvester and one modification in the harvester design found that the machine modification decreased relative dust intensity by 73%. The measurement tools described in this work can be used to provide rapid feedback on harvester operating conditions, orchard cultural practices, and machine design modifications.
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Affiliation(s)
- D Downey
- Biological and Agricultural Engineering, UC Davis, Davis, CA 95616, USA.
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LaRue RW, Dill BD, Giles DK, Whittimore JD, Raulston JE. Chlamydial Hsp60-2 is iron responsive in Chlamydia trachomatis serovar E-infected human endometrial epithelial cells in vitro. Infect Immun 2007; 75:2374-80. [PMID: 17307941 PMCID: PMC1865735 DOI: 10.1128/iai.01465-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Chlamydial 60-kDa heat shock proteins (cHsp60s) are known to play a prominent role in the immunopathogenesis of disease. It is also known that several stress-inducing growth conditions, such as heat, iron deprivation, or exposure to gamma interferon, result in the development of persistent chlamydial forms that often exhibit enhanced expression of cHsp60. We have shown previously that the expression of cHsp60 is greatly enhanced in Chlamydia trachomatis serovar E propagated in an iron-deficient medium. The objective of this work was to determine which single cHsp60 or combination of the three cHsp60 homologs encoded by this organism responds to iron limitation. Using monospecific polyclonal peptide antisera that recognize only cHsp60-1, cHsp60-2, or cHsp60-3, we found that expression of cHsp60-2 is responsive to iron deprivation. Overall, our studies suggest that the expression of cHsp60 homologs differs among the mechanisms currently known to induce persistence.
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Affiliation(s)
- Richard W LaRue
- Department of Microbiology, James H. Quillen College of Medicine, East Tennessee State University, P.O. Box 70579, Johnson City, TN 37614-1708, USA
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Giles DK, Whittimore JD, LaRue RW, Raulston JE, Wyrick PB. Ultrastructural analysis of chlamydial antigen-containing vesicles everting from the Chlamydia trachomatis inclusion. Microbes Infect 2006; 8:1579-91. [PMID: 16698305 DOI: 10.1016/j.micinf.2006.01.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 01/13/2006] [Accepted: 01/17/2006] [Indexed: 11/18/2022]
Abstract
Several chlamydial antigens have been detected in the infected epithelial cell cytosol and on the host cell surface prior to their presumed natural release at the end of the 72-96 h developmental cycle. These extra-inclusion antigens are proposed to influence vital host cell functions, antigen trafficking and presentation and, ultimately, contribute to a prolonged inflammatory response. To begin to dissect the mechanisms for escape of these antigens from the chlamydial inclusion, which are enhanced on exposure to antibiotics, polarized endometrial epithelial cells (HEC-1B) were infected with Chlamydia trachomatis serovar E for 36 h or 48 h. Infected cells were then exposed to chemotactic human polymorphonuclear neutrophils not loaded or pre-loaded in vitro with the antibiotic azithromycin. Viewed by electron microscopy, the azithromycin-mediated killing of chlamydiae involved an increase in chlamydial outer membrane blebbing followed by the appearance of the blebs in larger vesicles (i) everting from but still associated with the inclusion as well as (ii) external to the inclusion. Evidence that the vesicles originated from the chlamydial inclusion membrane was shown by immuno-localization of inclusion membrane proteins A, F, and G on the vesicular membranes. Chlamydial heat shock protein 60 (chsp60) copies 2 and 3, but not copy 1, were released from RB and incorporated into the everted inclusion membrane vesicles and delivered to the infected cell surface. These data represent direct evidence for one mechanism of early antigen delivery, albeit membrane-bound, beyond the confines of the chlamydial inclusion.
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Affiliation(s)
- David K Giles
- Department of Microbiology, Box 70579, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-0579, USA
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Ho MA, Squire LM, Sabeh NC, Giles DK, VanderGheynst JS. Design and evaluation of a grapevine pruner for biofungicide application. Bioresour Technol 2005; 96:963-968. [PMID: 15627568 DOI: 10.1016/j.biortech.2004.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 08/04/2004] [Accepted: 08/05/2004] [Indexed: 05/24/2023]
Abstract
Eutypa lata is a significant grapevine pathogen with limited means of prevention and control. The biological control agent Fusarium lateritium can prevent E. lata infection if applied directly onto a vine pruning wound. F. lateritium was suspended and stored in an invert emulsion formulation. A commercially available pruning shear was modified to dispense the formulated F. lateritium onto the cutting blade for direct application onto the pruning wound simultaneously with grapevine cutting. The modified pruner was tested for its ability to cover grapevine pruning wounds using the emulsion formulation. Efficacy of formulated F. lateritium on pruned grapevine canes was also studied using the pruner for application. Addition of grooves in the pruning blade significantly improved wound coverage. Biological efficacy testing determined that applying formulated F. lateritium with the modified pruner was as effective as pipetting formulation directly onto the pruning wound.
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Affiliation(s)
- M A Ho
- Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
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Stoller JK, Skibinski CI, Giles DK, Kester EL, Haney DJ. Physician-ordered respiratory care vs physician-ordered use of a respiratory therapy consult service. Results of a prospective observational study. Chest 1996; 110:422-9. [PMID: 8697845 DOI: 10.1378/chest.110.2.422] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVE To assess the impact of a respiratory therapy consult service (RTCS) on practices and appropriateness of ordering respiratory care services. DESIGN Nonrandomized prospective observational cohort study with concurrent controls. SETTING Adult non-ICU inpatient wards of an academic medical center. PATIENTS A convenience sample of 98 adult non-ICU inpatients at the Cleveland Clinic Hospital, representing 20 inpatient clinical services. Patients whose respiratory care plans were determined by respiratory care practitioners using sign and symptom-based algorithms to specify treatment comprised the treatment group (n = 51, respiratory therapy consult group). The nonconsult group (n = 47) were patients whose respiratory care plans were specified by their own physicians. INTERVENTION Specification of the respiratory care plan by the RTCS vs by the physicians themselves. Use of the RTCS was at the discretion of the managing physician. OUTCOME MEASURES Types and number of respiratory care treatments, length of hospital stay, costs of the respiratory therapy provided, appropriateness of respiratory care orders (based on comparison of the actual respiratory care orders with a reference respiratory care plan generated by a study investigator who was kept blind to the actual respiratory care plan), and adverse respiratory events. RESULTS Patients for whom the RTCS was requested by their physicians had a greater severity of respiratory illness based on having a lower triage score, but were otherwise similar at baseline. Fewer initial orders for respiratory care were discordant with the reference algorithms in RTCS patients (15% +/- 26% [SD]) than in nonconsult patients (43% +/- 36%; p < 0.001), and a smaller fraction of RTCS patients received at least one discordant initial respiratory care order (37% vs 72%; p < 0.001). Though provided to sicker patients with longer lengths of hospital stay, RTCS-directed care incurred similar respiratory care costs per patient ($335.63 +/- $272.69 [RTCS] vs $349.06 +/- $273.27; p = 0.72). CONCLUSIONS These results suggest that the RTCS can be an effective strategy to allocate respiratory care strategies appropriately while conserving the costs of providing respiratory care.
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Affiliation(s)
- J K Stoller
- Department of Pulmonary and Critical Care Medicine, Cleveland Clinic Foundation, OH 44195, USA
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Giles DK, Malloy R. Assessment instruments in respiratory care. Respir Care Clin N Am 1996; 2:77-91. [PMID: 9390871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The basis for using therapist-driven protocols effectively is an accurate assessment of the patient's respiratory status. Patients must be assessed to initiate indicated therapy and reassessed so that therapy can be modified or discontinued if no longer needed. This article addresses the role of respiratory therapists in patient assessment for the selection of appropriate and effective protocols. It also describes the use of a systematic and consistent process for patient assessment.
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Affiliation(s)
- D K Giles
- Department of Pulmonary and Critical Care Medicine, Cleveland Clinic Foundation, Ohio, USA
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Wolf MM, Hanley EL, King LA, Lachowicz J, Giles DK. The timer-game: a variable interval contingency for the management of out-of-seat behavior. Except Child 1970; 37:113-117. [PMID: 5506647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Giles DK, Wolf MM. Toilet training institutionalized, severe retardates: an application of operant behavior modification techniques. Am J Ment Defic 1966; 70:766-80. [PMID: 5908530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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