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Henry SA, Webster CM, Shaw LN, Torres NJ, Jobson ME, Totzke BC, Jackson JK, McGreig JE, Wass MN, Robinson GK, Shepherd M. Steroid Drugs Inhibit Bacterial Respiratory Oxidases and Are Lethal Toward Methicillin-Resistant Staphylococcus aureus. J Infect Dis 2024; 230:e149-e158. [PMID: 39052707 PMCID: PMC11272085 DOI: 10.1093/infdis/jiad540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/28/2023] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Cytochrome bd complexes are respiratory oxidases found exclusively in prokaryotes that are important during infection for numerous bacterial pathogens. METHODS In silico docking was employed to screen approved drugs for their ability to bind to the quinol site of Escherichia coli cytochrome bd-I. Respiratory inhibition was assessed with oxygen electrodes using membranes isolated from E. coli and methicillin-resistant Staphylococcus aureus strains expressing single respiratory oxidases (ie, cytochromes bd, bo', or aa3). Growth/viability assays were used to measure bacteriostatic and bactericidal effects. RESULTS The steroid drugs ethinylestradiol and quinestrol inhibited E. coli bd-I activity with median inhibitory concentration (IC50) values of 47 ± 28.9 µg/mL (158 ± 97.2 µM) and 0.2 ± 0.04 µg/mL (0.5 ± 0.1 µM), respectively. Quinestrol inhibited growth of an E. coli "bd-I only" strain with an IC50 of 0.06 ± 0.02 µg/mL (0.2 ± 0.07 µM). Growth of an S. aureus "bd only" strain was inhibited by quinestrol with an IC50 of 2.2 ± 0.43 µg/mL (6.0 ± 1.2 µM). Quinestrol exhibited potent bactericidal effects against S. aureus but not E. coli. CONCLUSIONS Quinestrol inhibits cytochrome bd in E. coli and S. aureus membranes and inhibits the growth of both species, yet is only bactericidal toward S. aureus.
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Affiliation(s)
- Samantha A Henry
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Calum M Webster
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Lindsey N Shaw
- Department of Molecular Biosciences, University of South Florida, Tampa
| | | | | | - Brendan C Totzke
- Department of Molecular Biosciences, University of South Florida, Tampa
| | - Jessica K Jackson
- Department of Molecular Biosciences, University of South Florida, Tampa
| | - Jake E McGreig
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Mark N Wass
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Gary K Robinson
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Mark Shepherd
- School of Biosciences, University of Kent, Canterbury, United Kingdom
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2
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Lewis JM, Jebeli L, Coulon PML, Lay CE, Scott NE. Glycoproteomic and proteomic analysis of Burkholderia cenocepacia reveals glycosylation events within FliF and MotB are dispensable for motility. Microbiol Spectr 2024; 12:e0034624. [PMID: 38709084 PMCID: PMC11237607 DOI: 10.1128/spectrum.00346-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/16/2024] [Indexed: 05/07/2024] Open
Abstract
Across the Burkholderia genus O-linked protein glycosylation is highly conserved. While the inhibition of glycosylation has been shown to be detrimental for virulence in Burkholderia cepacia complex species, such as Burkholderia cenocepacia, little is known about how specific glycosylation sites impact protein functionality. Within this study, we sought to improve our understanding of the breadth, dynamics, and requirement for glycosylation across the B. cenocepacia O-glycoproteome. Assessing the B. cenocepacia glycoproteome across different culture media using complementary glycoproteomic approaches, we increase the known glycoproteome to 141 glycoproteins. Leveraging this repertoire of glycoproteins, we quantitively assessed the glycoproteome of B. cenocepacia using Data-Independent Acquisition (DIA) revealing the B. cenocepacia glycoproteome is largely stable across conditions with most glycoproteins constitutively expressed. Examination of how the absence of glycosylation impacts the glycoproteome reveals that the protein abundance of only five glycoproteins (BCAL1086, BCAL2974, BCAL0525, BCAM0505, and BCAL0127) are altered by the loss of glycosylation. Assessing ΔfliF (ΔBCAL0525), ΔmotB (ΔBCAL0127), and ΔBCAM0505 strains, we demonstrate the loss of FliF, and to a lesser extent MotB, mirror the proteomic effects observed in the absence of glycosylation in ΔpglL. While both MotB and FliF are essential for motility, we find loss of glycosylation sites in MotB or FliF does not impact motility supporting these sites are dispensable for function. Combined this work broadens our understanding of the B. cenocepacia glycoproteome supporting that the loss of glycoproteins in the absence of glycosylation is not an indicator of the requirement for glycosylation for protein function. IMPORTANCE Burkholderia cenocepacia is an opportunistic pathogen of concern within the Cystic Fibrosis community. Despite a greater appreciation of the unique physiology of B. cenocepacia gained over the last 20 years a complete understanding of the proteome and especially the O-glycoproteome, is lacking. In this study, we utilize systems biology approaches to expand the known B. cenocepacia glycoproteome as well as track the dynamics of glycoproteins across growth phases, culturing media and in response to the loss of glycosylation. We show that the glycoproteome of B. cenocepacia is largely stable across conditions and that the loss of glycosylation only impacts five glycoproteins including the motility associated proteins FliF and MotB. Examination of MotB and FliF shows, while these proteins are essential for motility, glycosylation is dispensable. Combined this work supports that B. cenocepacia glycosylation can be dispensable for protein function and may influence protein properties beyond stability.
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Affiliation(s)
- Jessica M Lewis
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Pauline M L Coulon
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Catrina E Lay
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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3
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Ghazali AK, Firdaus-Raih M, Uthaya Kumar A, Lee WK, Hoh CC, Nathan S. Transitioning from Soil to Host: Comparative Transcriptome Analysis Reveals the Burkholderia pseudomallei Response to Different Niches. Microbiol Spectr 2023; 11:e0383522. [PMID: 36856434 PMCID: PMC10100664 DOI: 10.1128/spectrum.03835-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/06/2023] [Indexed: 03/02/2023] Open
Abstract
Burkholderia pseudomallei, a soil and water saprophyte, is responsible for the tropical human disease melioidosis. A hundred years since its discovery, there is still much to learn about B. pseudomallei proteins that are essential for the bacterium's survival in and interaction with the infected host, as well as their roles within the bacterium's natural soil habitat. To address this gap, bacteria grown under conditions mimicking the soil environment were subjected to transcriptome sequencing (RNA-seq) analysis. A dual RNA-seq approach was used on total RNA from spleens isolated from a B. pseudomallei mouse infection model at 5 days postinfection. Under these conditions, a total of 1,434 bacterial genes were induced, with 959 induced in the soil environment and 475 induced in bacteria residing within the host. Genes encoding metabolism and transporter proteins were induced when the bacteria were present in soil, while virulence factors, metabolism, and bacterial defense mechanisms were upregulated during active infection of mice. On the other hand, capsular polysaccharide and quorum-sensing pathways were inhibited during infection. In addition to virulence factors, reactive oxygen species, heat shock proteins, siderophores, and secondary metabolites were also induced to assist bacterial adaptation and survival in the host. Overall, this study provides crucial insights into the transcriptome-level adaptations which facilitate infection by soil-dwelling B. pseudomallei. Targeting novel therapeutics toward B. pseudomallei proteins required for adaptation provides an alternative treatment strategy given its intrinsic antimicrobial resistance and the absence of a vaccine. IMPORTANCE Burkholderia pseudomallei, a soil-dwelling bacterium, is the causative agent of melioidosis, a fatal infectious disease of humans and animals. The bacterium has a large genome consisting of two chromosomes carrying genes that encode proteins with important roles for survival in diverse environments as well as in the infected host. While a general mechanism of pathogenesis has been proposed, it is not clear which proteins have major roles when the bacteria are in the soil and whether the same proteins are key to successful infection and spread. To address this question, we grew the bacteria in soil medium and then in infected mice. At 5 days postinfection, bacteria were recovered from infected mouse organs and their gene expression was compared against that of bacteria grown in soil medium. The analysis revealed a list of genes expressed under soil growth conditions and a different set of genes encoding proteins which may be important for survival, replication, and dissemination in an infected host. These proteins are a potential resource for understanding the full adaptation mechanism of this pathogen. In the absence of a vaccine for melioidosis and with treatment being reliant on combinatorial antibiotic therapy, these proteins may be ideal targets for designing antimicrobials to treat melioidosis.
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Affiliation(s)
- Ahmad-Kamal Ghazali
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Asqwin Uthaya Kumar
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Wei-Kang Lee
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics Sdn. Bhd., Seri Kembangan, Selangor, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
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4
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Seng R, Phunpang R, Saiprom N, Dulsuk A, Chewapreecha C, Thaipadungpanit J, Batty EM, Chantratita W, West TE, Chantratita N. Phenotypic and genetic alterations of Burkholderia pseudomallei in patients during relapse and persistent infections. Front Microbiol 2023; 14:1103297. [PMID: 36814569 PMCID: PMC9939903 DOI: 10.3389/fmicb.2023.1103297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 01/09/2023] [Indexed: 02/09/2023] Open
Abstract
The bacterium Burkholderia pseudomallei is the causative agent of melioidosis, a severe tropical disease associated with high mortality and relapse and persistent infections. Treatment of melioidosis requires prolonged antibiotic therapy; however, little is known about relapse and persistent infections, particularly the phenotypic and genetic alterations of B. pseudomallei in patients. In this study, we performed pulsed-field gel electrophoresis (PFGE) to compare the bacterial genotype between the initial isolate and the subsequent isolate from each of 23 suspected recurrent and persistent melioidosis patients in Northeast Thailand. We used whole-genome sequencing (WGS) to investigate multilocus sequence types and genetic alterations of within-host strain pairs. We also investigated the bacterial phenotypes associated with relapse and persistent infections, including multinucleated giant cell (MNGC) formation efficiency and intracellular multiplication. We first identified 13 (1.2%) relapse, 7 (0.7%) persistent, and 3 (0.3%) reinfection patients from 1,046 survivors. Each of the 20 within-host strain pairs from patients with relapse and persistent infections shared the same genotype, suggesting that the subsequent isolates arise from the infecting isolate. Logistic regression analysis of clinical data revealed regimen and duration of oral antibiotic therapies as risk factors associated with relapse and persistent infections. WGS analysis demonstrated 17 within-host genetic alteration events in 6 of 20 paired isolates, including a relatively large deletion and 16 single-nucleotide polymorphism (stocktickerSNP) mutations distributed across 12 genes. In 1 of 20 paired isolates, we observed significantly increased cell-to-cell fusion and intracellular replication in the second isolate compared with the initial isolate from a patient with persistent infection. WGS analysis suggested that a non-synonymous mutation in the tssB-5 gene, which encoded an essential component of the type VI secretion system, may be associated with the increased intracellular replication and MNGC formation efficiency of the second isolate of the patient. This information provides insights into genetic and phenotypic alterations in B. pseudomallei in human melioidosis, which may represent a bacterial strategy for persistent and relapse infections.
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Affiliation(s)
- Rathanin Seng
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rungnapa Phunpang
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Natnaree Saiprom
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Adul Dulsuk
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Parasites and Microbes, Wellcome Sanger Institute, Cambridge, United Kingdom
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Janjira Thaipadungpanit
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Elizabeth M. Batty
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Wasun Chantratita
- Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - T. Eoin West
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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5
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Madden DE, McCarthy KL, Bell SC, Olagoke O, Baird T, Neill J, Ramsay KA, Kidd TJ, Stewart AG, Subedi S, Choong K, Fraser TA, Sarovich DS, Price EP. Rapid fluoroquinolone resistance detection in Pseudomonas aeruginosa using mismatch amplification mutation assay-based real-time PCR. J Med Microbiol 2022; 71. [DOI: 10.1099/jmm.0.001593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background. Antimicrobial resistance (AMR) is an ever-increasing global health concern. One crucial facet in tackling the AMR epidemic is earlier and more accurate AMR diagnosis, particularly in the dangerous and highly multi-drug-resistant ESKAPE pathogen,
Pseudomonas aeruginosa
.
Objectives. We aimed to develop two SYBR Green-based mismatch amplification mutation assays (SYBR-MAMAs) targeting GyrA T83I (gyrA248) and GyrA D87N, D87Y and D87H (gyrA259). Together, these variants cause the majority of fluoroquinolone (FQ) AMR in
P. aeruginosa
.
Methods. Following assay validation, the gyrA248 and gyrA259 SYBR-MAMAs were tested on 84 Australian clinical
P. aeruginosa
isolates, 46 of which demonstrated intermediate/full ciprofloxacin resistance according to antimicrobial susceptibility testing.
Results. Our two SYBR-MAMAs correctly predicted an AMR phenotype in the majority (83%) of isolates with intermediate/full FQ resistance. All FQ-sensitive strains were predicted to have a sensitive phenotype. Whole-genome sequencing confirmed 100 % concordance with SYBR-MAMA genotypes.
Conclusions. Our GyrA SYBR-MAMAs provide a rapid and cost-effective method for same-day identification of FQ AMR in
P. aeruginosa
. An additional SYBR-MAMA targeting the GyrB S466Y/S466F variants would increase FQ AMR prediction to 91 %. Clinical implementation of our assays will permit more timely treatment alterations in cases where decreased FQ susceptibility is identified, leading to improved patient outcomes and antimicrobial stewardship.
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Affiliation(s)
- Danielle E. Madden
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Kate L. McCarthy
- University of Queensland Centre for Clinical Research, Herston, Queensland, Australia
- Infectious Diseases Unit, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia
| | - Scott C. Bell
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia
- Child Health Research Centre, The University of Queensland, South Brisbane, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Olusola Olagoke
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
| | - Timothy Baird
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Respiratory Department, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Jane Neill
- Respiratory Department, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Kay A. Ramsay
- Child Health Research Centre, The University of Queensland, South Brisbane, Queensland, Australia
| | - Timothy J. Kidd
- Central Microbiology, Pathology Queensland, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
| | - Adam G. Stewart
- Infectious Diseases Unit, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
- University of Queensland Centre for Clinical Research, Herston, Queensland, Australia
| | - Shradha Subedi
- Infectious Diseases Unit, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
| | - Keat Choong
- Infectious Diseases Unit, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
| | - Tamieka A. Fraser
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Derek S. Sarovich
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Erin P. Price
- Centre for Bioinnovation, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Infection Research Network Sunshine Coast, Birtinya, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
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6
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Burkholderia pseudomallei JW270 Is Lethal in the Madagascar Hissing Cockroach Infection Model and Can Be Utilized at Biosafety Level 2 to Identify Putative Virulence Factors. Infect Immun 2022; 90:e0015922. [PMID: 35862734 PMCID: PMC9387215 DOI: 10.1128/iai.00159-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Burkholderia pseudomallei, the causative agent of melioidosis, is classified by the CDC as a tier 1 select agent, and work involving it must be performed in a biosafety level 3 (BSL-3) laboratory. Three BSL-2 surrogate strains derived from B. pseudomallei 1026b, a virulent clinical isolate, have been removed from the CDC select agent list. These strains, Bp82, B0011, and JW270, are highly attenuated in rodent models of melioidosis and cannot be utilized to identify virulence determinants because of their high 50% lethal dose (LD50). We previously demonstrated that the Madagascar hissing cockroach (MHC) is a tractable surrogate host to study the innate immune response against Burkholderia. In this study, we found that JW270 maintains its virulence in MHCs. This surprising result indicates that it may be possible to identify potential virulence genes in JW270 by using MHCs at BSL-2. We tested this hypothesis by constructing JW270 mutations in genes that are required (hcp1) or dispensable (hcp2) for B. pseudomallei virulence in rodents. JW270 Δhcp1 was avirulent in MHCs and JW270 Δhcp2 was virulent, suggesting that MHCs can be used at BSL-2 for the discovery of important virulence factors. JW270 ΔBPSS2185, a strain harboring a mutation in a type IV pilin locus (TFP8) required for full virulence in BALB/c mice, was also found to be attenuated in MHCs. Finally, we demonstrate that the hmqA-G locus, which encodes the production of a family of secondary metabolites called 4-hydroxy-3-methyl-2-alkylquinolines, is important for JW270 virulence in MHCs and may represent a novel virulence determinant.
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7
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Friedrich T, Wohlwend D, Borisov VB. Recent Advances in Structural Studies of Cytochrome bd and Its Potential Application as a Drug Target. Int J Mol Sci 2022; 23:ijms23063166. [PMID: 35328590 PMCID: PMC8951039 DOI: 10.3390/ijms23063166] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023] Open
Abstract
Cytochrome bd is a triheme copper-free terminal oxidase in membrane respiratory chains of prokaryotes. This unique molecular machine couples electron transfer from quinol to O2 with the generation of a proton motive force without proton pumping. Apart from energy conservation, the bd enzyme plays an additional key role in the microbial cell, being involved in the response to different environmental stressors. Cytochrome bd promotes virulence in a number of pathogenic species that makes it a suitable molecular drug target candidate. This review focuses on recent advances in understanding the structure of cytochrome bd and the development of its selective inhibitors.
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Affiliation(s)
- Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany; (T.F.); (D.W.)
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany; (T.F.); (D.W.)
| | - Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia
- Correspondence:
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8
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Mutators Enhance Adaptive Micro-Evolution in Pathogenic Microbes. Microorganisms 2022; 10:microorganisms10020442. [PMID: 35208897 PMCID: PMC8875331 DOI: 10.3390/microorganisms10020442] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/07/2022] [Accepted: 02/10/2022] [Indexed: 02/04/2023] Open
Abstract
Adaptation to the changing environmental conditions experienced within a host requires genetic diversity within a microbial population. Genetic diversity arises from mutations which occur due to DNA damage from exposure to exogenous environmental stresses or generated endogenously through respiration or DNA replication errors. As mutations can be deleterious, a delicate balance must be obtained between generating enough mutations for micro-evolution to occur while maintaining fitness and genomic integrity. Pathogenic microorganisms can actively modify their mutation rate to enhance adaptive micro-evolution by increasing expression of error-prone DNA polymerases or by mutating or decreasing expression of genes required for DNA repair. Strains which exhibit an elevated mutation rate are termed mutators. Mutators are found in varying prevalence in clinical populations where large-effect beneficial mutations enhance survival and are predominately caused by defects in the DNA mismatch repair (MMR) pathway. Mutators can facilitate the emergence of antibiotic resistance, allow phenotypic modifications to prevent recognition and destruction by the host immune system and enable switching to metabolic and cellular morphologies better able to survive in the given environment. This review will focus on recent advances in understanding the phenotypic and genotypic changes occurring in MMR mutators in both prokaryotic and eukaryotic pathogens.
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9
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Webb KA, Olagoke O, Baird T, Neill J, Pham A, Wells TJ, Ramsay KA, Bell SC, Sarovich DS, Price EP. Genomic diversity and antimicrobial resistance of Prevotella species isolated from chronic lung disease airways. Microb Genom 2022; 8. [PMID: 35113778 PMCID: PMC8942031 DOI: 10.1099/mgen.0.000754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are characterized by increasingly frequent acute pulmonary exacerbations that reduce life quality and length. Human airways are home to a rich polymicrobial environment, which includes members of the obligately anaerobic genus Prevotella. Despite their commonness, surprisingly little is known about the prevalence, role, genomic diversity and antimicrobial resistance (AMR) potential of Prevotella species and strains in healthy and diseased airways. Here, we used comparative genomics to develop a real-time PCR assay to permit rapid Prevotella species identification and quantification from cultures and clinical specimens. Assay specificity was validated across a panel of Prevotella and non-Prevotella species, followed by PCR screening of CF and COPD respiratory-derived cultures. Next, 35 PCR-positive isolates were subjected to whole-genome sequencing. Of eight identified Prevotella species, P. histicola, P. melaninogenica, P. nanceiensis, P. salivae and P. denticola overlapped between participant cohorts. Phylogenomic analysis revealed considerable interhost but limited intrahost diversity, suggesting patient-specific lineages in the lower airways, probably from oral cavity aspirations. Correlation of phenotypic AMR profiles with AMR genes identified excellent correlation between tetQ presence and decreased doxycycline susceptibility, and ermF presence and decreased azithromycin susceptibility and clindamycin resistance. AMR rates were higher in the CF isolates, reflecting greater antibiotic use in this cohort. All tested Prevotella isolates were tobramycin-resistant, providing a potential selection method to improve Prevotella culture retrieval rates. Our addition of 35 airway-derived Prevotella genomes to public databases will enhance ongoing efforts to unravel the role of this diverse and enigmatic genus in both diseased and healthy lungs.
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Affiliation(s)
- Kasey A Webb
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Olusola Olagoke
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Timothy Baird
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.,Sunshine Coast Hospital and Health Service, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Jane Neill
- Sunshine Coast Hospital and Health Service, Sunshine Coast University Hospital, Birtinya, Queensland, Australia
| | - Amy Pham
- University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Queensland, Australia
| | - Timothy J Wells
- University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, Queensland, Australia
| | - Kay A Ramsay
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia.,Present address: Child Health Research Centre, The University of Queensland, Centre for Children's Health Research, South Brisbane, Queensland, Australia
| | - Scott C Bell
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia.,Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia.,Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Derek S Sarovich
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Erin P Price
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Sunshine Coast Health Institute, Birtinya, Queensland, Australia
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10
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Mou S, Jenkins CC, Okaro U, Dhummakupt ES, Mach PM, DeShazer D. The Burkholderia pseudomallei hmqA-G Locus Mediates Competitive Fitness against Environmental Gram-Positive Bacteria. Microbiol Spectr 2021; 9:e0010221. [PMID: 34160272 PMCID: PMC8552763 DOI: 10.1128/spectrum.00102-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/21/2022] Open
Abstract
Burkholderia pseudomallei is an opportunistic pathogen that is responsible for the disease melioidosis in humans and animals. The microbe is a tier 1 select agent because it is highly infectious by the aerosol route, it is inherently resistant to multiple antibiotics, and no licensed vaccine currently exists. Naturally acquired infections result from contact with contaminated soil or water sources in regions of endemicity. There have been few reports investigating the molecular mechanism(s) utilized by B. pseudomallei to survive and persist in ecological niches harboring microbial competitors. Here, we report the isolation of Gram-positive bacteria from multiple environmental sources and show that ∼45% of these isolates are inhibited by B. pseudomallei in head-to-head competition assays. Two competition-deficient B. pseudomallei transposon mutants were identified that contained insertion mutations in the hmqA-G operon. This large biosynthetic gene cluster encodes the enzymes that produce a family of secondary metabolites called 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs). Liquid chromatography and mass spectrometry conducted on filter-sterilized culture supernatants revealed five HMAQs and N-oxide derivatives that were produced by the parental strain but were absent in an isogenic hmqD deletion mutant. The results demonstrate that B. pseudomallei inhibits the growth of environmental Gram-positive bacteria in a contact-independent manner via the production of HMAQs by the hmqA-G operon. IMPORTANCE Burkholderia pseudomallei naturally resides in water, soil, and the rhizosphere and its success as an opportunistic pathogen is dependent on the ability to persist in these harsh habitats long enough to come into contact with a susceptible host. In addition to adapting to limiting nutrients and diverse chemical and physical challenges, B. pseudomallei also has to interact with a variety of microbial competitors. Our research shows that one of the ways in which B. pseudomallei competes with Gram-positive environmental bacteria is by exporting a diverse array of closely related antimicrobial secondary metabolites.
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Affiliation(s)
- Sherry Mou
- Foundational Sciences Directorate, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | - Conor C. Jenkins
- Excet Inc., Springfield, Virginia, USA
- DEVCOM Chemical Biological Center, Aberdeen Proving Ground, Maryland, USA
| | - Udoka Okaro
- Foundational Sciences Directorate, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
| | | | - Phillip M. Mach
- DEVCOM Chemical Biological Center, Aberdeen Proving Ground, Maryland, USA
| | - David DeShazer
- Foundational Sciences Directorate, Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, USA
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11
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Abstract
Bacteria in the Burkholderia cepacia complex (BCC) are significant pathogens for people with cystic fibrosis (CF) and are often extensively antibiotic resistant. Here, we assess the impacts of clinically observed mutations in fixL, which encodes the sensor histidine kinase FixL. FixL along with FixJ compose a two-component system that regulates multiple phenotypes. Mutations in fixL across two species, B. dolosa and B. multivorans, have shown evidence of positive selection during chronic lung infection in CF. Herein, we find that BCC carrying the conserved, ancestral fixL sequence have lower survival in macrophages and in murine pneumonia models than mutants carrying evolved fixL sequences associated with clinical decline in CF patients. In vitro phosphotransfer experiments found that one evolved FixL protein, W439S, has a reduced ability to autophosphorylate and phosphorylate FixJ, while LacZ reporter experiments demonstrate that B. dolosa carrying evolved fixL alleles has reduced fix pathway activity. Interestingly, B. dolosa carrying evolved fixL alleles was less fit in a soil assay than those strains carrying the ancestral allele, demonstrating that increased survival of these variants in macrophages and the murine lung comes at a potential expense in their environmental reservoir. Thus, modulation of the two-component system encoded by fixLJ by point mutations is one mechanism that allows BCC to adapt to the host infection environment.
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12
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Presence of the Hmq System and Production of 4-Hydroxy-3-Methyl-2-Alkylquinolines Are Heterogeneously Distributed between Burkholderia cepacia Complex Species and More Prevalent among Environmental than Clinical Isolates. Microbiol Spectr 2021; 9:e0012721. [PMID: 34132614 PMCID: PMC8552760 DOI: 10.1128/spectrum.00127-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Burkholderia cepacia complex (Bcc) comprises several species of closely related, versatile bacteria. Some Bcc strains produce 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), analogous to the 4-hydroxy-2-alkylquinolines of Pseudomonas aeruginosa. Using in silico analyses, we previously estimated that the hmqABCDEFG operon, which encodes enzymes involved in the biosynthesis of HMAQs, is carried by about one-third of Bcc strains, with considerable inter- and intraspecies variability. In the present study, we investigated by PCR, using consensus primers, the distribution of hmqABCDEFG in a collection of 312 Bcc strains (222 of clinical and 90 of environmental origins) belonging to 18 Bcc species. We confirmed that this operon is not distributed evenly among Bcc species. Among the 30% of strains bearing the hmqABCDEFG operon, we found that 92% of environmental isolates and 82% of clinically isolated Bcc strains produce levels of HMAQs detectable by liquid chromatography-mass spectrometry in at least one of the tested culture conditions. Among the hmqABCDEFG-positive but HMAQ-negative strains, none expressed the hmqA gene under the specified culture conditions. Interestingly, the hmqABCDEFG operon is more prevalent among plant root environment species (e.g., Burkholderia ambifaria and Burkholderia cepacia) and absent in species commonly found in chronically colonized individuals with cystic fibrosis (e.g., Burkholderia cenocepacia and Burkholderia multivorans), suggesting a role for the Hmq system in niche adaptation. We investigated the impact of the Hmq system on plant growth promotion and found that Pisum sativum root development by B. ambifaria required a functional HMAQ system. IMPORTANCE Environmental bacteria belonging to the various closely related species forming the Burkholderia cepacia complex (Bcc) can infect plants and animals, including humans. Their pathogenicity is regulated by intercellular communication, or quorum sensing, allowing them to collaborate instead of acting individually. Bcc organisms generally exploit interacting quorum sensing systems based on N-acyl-homoserine lactones as signaling molecules. Several Bcc strains also carry an hmqABCDEFG operon responsible for the biosynthesis of 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), molecules analogous to the Pseudomonas quinolone signal (PQS) system of P. aeruginosa. Our finding that the prevalences of the Hmq system and HMAQ production are very different between various Bcc species suggests a key role in niche adaptation or pathogenicity. This is supported by a significant reduction in plant growth promotion in the absence of HMAQ production for a beneficial Bcc strain.
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13
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Molecular Epidemiology of Third-Generation-Cephalosporin-Resistant Enterobacteriaceae in Southeast Queensland, Australia. Antimicrob Agents Chemother 2021; 65:AAC.00130-21. [PMID: 33781999 DOI: 10.1128/aac.00130-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/10/2021] [Indexed: 01/23/2023] Open
Abstract
Third-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae represent a major threat to human health. Here, we captured 288 3GC-R Enterobacteriaceae clinical isolates from 264 patients presenting at a regional Australian hospital over a 14-month period. In addition to routine mass spectrometry and antibiotic sensitivity testing, isolates were examined using rapid (∼40-min) real-time PCR assays targeting the most common extended-spectrum β-lactamases (ESBLs; bla CTX-M-1 and bla CTX-M-9 groups, plus bla TEM, bla SHV, and an internal 16S rRNA gene control). AmpC CMY β-lactamase (bla CMY) prevalence was also examined. Escherichia coli (80.2%) and Klebsiella pneumoniae (17.0%) were dominant, with Klebsiella oxytoca, Klebsiella aerogenes, and Enterobacter cloacae infrequently identified. Ceftriaxone and cefoxitin resistance were identified in 97.0% and 24.5% of E. coli and K. pneumoniae isolates, respectively. Consistent with global findings in Enterobacteriaceae, most (98.3%) isolates harbored at least one β-lactamase gene, with 144 (50%) harboring bla CTX-M-1 group, 92 (31.9%) harboring bla CTX-M-9 group, 48 (16.7%) harboring bla SHV, 133 (46.2%) harboring bla TEM, and 34 (11.8%) harboring bla CMY genes. A subset of isolates (n = 98) were subjected to whole-genome sequencing (WGS) to identify the presence of cryptic resistance determinants and to verify genotyping accuracy. WGS of β-lactamase-negative or carbapenem-resistant isolates identified uncommon ESBL and carbapenemase genes, including bla NDM and bla IMP, and confirmed all PCR-positive genotypes. We demonstrate that our PCR assays enable the rapid and cost-effective identification of ESBLs in the hospital setting, which has important infection control and therapeutic implications.
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14
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Heacock-Kang Y, McMillan IA, Norris MH, Sun Z, Zarzycki-Siek J, Bluhm AP, Cabanas D, Norton RE, Ketheesan N, Miller JF, Schweizer HP, Hoang TT. The Burkholderia pseudomallei intracellular 'TRANSITome'. Nat Commun 2021; 12:1907. [PMID: 33772012 PMCID: PMC7998038 DOI: 10.1038/s41467-021-22169-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a 'TRANSITomic' approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei 'TRANSITome' reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei 'TRANSITome' provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.
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Affiliation(s)
- Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert E Norton
- Townsville Hospital, Townsville, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Natkunam Ketheesan
- Science and Technology, University of New England, New South Wales, Australia
| | - Jeff F Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and the California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA.
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15
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Chomkatekaew C, Boonklang P, Sangphukieo A, Chewapreecha C. An Evolutionary Arms Race Between Burkholderia pseudomallei and Host Immune System: What Do We Know? Front Microbiol 2021; 11:612568. [PMID: 33552023 PMCID: PMC7858667 DOI: 10.3389/fmicb.2020.612568] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
A better understanding of co-evolution between pathogens and hosts holds promise for better prevention and control strategies. This review will explore the interactions between Burkholderia pseudomallei, an environmental and opportunistic pathogen, and the human host immune system. B. pseudomallei causes "Melioidosis," a rapidly fatal tropical infectious disease predicted to affect 165,000 cases annually worldwide, of which 89,000 are fatal. Genetic heterogeneities were reported in both B. pseudomallei and human host population, some of which may, at least in part, contribute to inter-individual differences in disease susceptibility. Here, we review (i) a multi-host-pathogen characteristic of the interaction; (ii) selection pressures acting on B. pseudomallei and human genomes with the former being driven by bacterial adaptation across ranges of ecological niches while the latter are driven by human encounter of broad ranges of pathogens; (iii) the mechanisms that generate genetic diversity in bacterial and host population particularly in sequences encoding proteins functioning in host-pathogen interaction; (iv) reported genetic and structural variations of proteins or molecules observed in B. pseudomallei-human host interactions and their implications in infection outcomes. Together, these predict bacterial and host evolutionary trajectory which continues to generate genetic diversity in bacterium and operates host immune selection at the molecular level.
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Affiliation(s)
| | | | - Apiwat Sangphukieo
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Claire Chewapreecha
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
- Bioinformatics and Systems Biology Program, School of Bioresource and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
- Wellcome Sanger Institute, Hinxton, United Kingdom
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16
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Grund ME, Choi SJ, McNitt DH, Barbier M, Hu G, LaSala PR, Cote CK, Berisio R, Lukomski S. Burkholderia collagen-like protein 8, Bucl8, is a unique outer membrane component of a putative tetrapartite efflux pump in Burkholderia pseudomallei and Burkholderia mallei. PLoS One 2020; 15:e0242593. [PMID: 33227031 PMCID: PMC7682875 DOI: 10.1371/journal.pone.0242593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/06/2020] [Indexed: 12/19/2022] Open
Abstract
Bacterial efflux pumps are an important pathogenicity trait because they extrude a variety of xenobiotics. Our laboratory previously identified in silico Burkholderia collagen-like protein 8 (Bucl8) in the hazardous pathogens Burkholderia pseudomallei and Burkholderia mallei. We hypothesize that Bucl8, which contains two predicted tandem outer membrane efflux pump domains, is a component of a putative efflux pump. Unique to Bucl8, as compared to other outer membrane proteins, is the presence of an extended extracellular region containing a collagen-like (CL) domain and a non-collagenous C-terminus (Ct). Molecular modeling and circular dichroism spectroscopy with a recombinant protein, corresponding to this extracellular CL-Ct portion of Bucl8, demonstrated that it adopts a collagen triple helix, whereas functional assays screening for Bucl8 ligands identified binding to fibrinogen. Bioinformatic analysis of the bucl8 gene locus revealed it resembles a classical efflux-pump operon. The bucl8 gene is co-localized with downstream fusCDE genes encoding fusaric acid (FA) resistance, and with an upstream gene, designated as fusR, encoding a LysR-type transcriptional regulator. Using reverse transcriptase (RT)-qPCR, we defined the boundaries and transcriptional organization of the fusR-bucl8-fusCDE operon. We found exogenous FA induced bucl8 transcription over 80-fold in B. pseudomallei, while deletion of the entire bucl8 locus decreased the minimum inhibitory concentration of FA 4-fold in its isogenic mutant. We furthermore showed that the putative Bucl8-associated pump expressed in the heterologous Escherichia coli host confers FA resistance. On the contrary, the Bucl8-associated pump did not confer resistance to a panel of clinically-relevant antimicrobials in Burkholderia and E. coli. We finally demonstrated that deletion of the bucl8-locus drastically affects the growth of the mutant in L-broth. We determined that Bucl8 is a component of a novel tetrapartite efflux pump, which confers FA resistance, fibrinogen binding, and optimal growth.
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Affiliation(s)
- Megan E. Grund
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Soo J. Choi
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Dudley H. McNitt
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Mariette Barbier
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
| | - Gangqing Hu
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
- Cancer Center, West Virginia University, Morgantown, WV, United States of
America
- Bioinformatics Core, West Virginia University, Morgantown, WV, United
States of America
| | - P. Rocco LaSala
- Department of Pathology, West Virginia University, Morgantown, WV, United
States of America
| | - Christopher K. Cote
- Bacteriology Division, The United States Army Medical Research Institute
of Infectious Diseases (USAMRIID), Frederick, MD, United States of
America
| | - Rita Berisio
- Institute of Biostructures and Bioimaging, National Research Council,
Naples, Italy
| | - Slawomir Lukomski
- Department of Microbiology, Immunology and Cell Biology, School of
Medicine, West Virginia University, Morgantown, WV, United States of
America
- Cancer Center, West Virginia University, Morgantown, WV, United States of
America
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17
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Price EP, Soler Arango V, Kidd TJ, Fraser TA, Nguyen TK, Bell SC, Sarovich DS. Duplex real-time PCR assay for the simultaneous detection of Achromobacter xylosoxidans and Achromobacter spp. Microb Genom 2020; 6:mgen000406. [PMID: 32667877 PMCID: PMC7478622 DOI: 10.1099/mgen.0.000406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/26/2020] [Indexed: 01/10/2023] Open
Abstract
Several members of the Gram-negative environmental bacterial genus Achromobacter are associated with serious infections, with Achromobacter xylosoxidans being the most common. Despite their pathogenic potential, little is understood about these intrinsically drug-resistant bacteria and their role in disease, leading to suboptimal diagnosis and management. Here, we performed comparative genomics for 158 Achromobacter spp. genomes to robustly identify species boundaries, reassign several incorrectly speciated taxa and identify genetic sequences specific for the genus Achromobacter and for A. xylosoxidans. Next, we developed a Black Hole Quencher probe-based duplex real-time PCR assay, Ac-Ax, for the rapid and simultaneous detection of Achromobacter spp. and A. xylosoxidans from both purified colonies and polymicrobial clinical specimens. Ac-Ax was tested on 119 isolates identified as Achromobacter spp. using phenotypic or genotypic methods. In comparison to these routine diagnostic methods, the duplex assay showed superior identification of Achromobacter spp. and A. xylosoxidans, with five Achromobacter isolates failing to amplify with Ac-Ax confirmed to be different genera according to 16S rRNA gene sequencing. Ac-Ax quantified both Achromobacter spp. and A. xylosoxidans down to ~110 genome equivalents and detected down to ~12 and ~1 genome equivalent(s), respectively. Extensive in silico analysis, and laboratory testing of 34 non-Achromobacter isolates and 38 adult cystic fibrosis sputa, confirmed duplex assay specificity and sensitivity. We demonstrate that the Ac-Ax duplex assay provides a robust, sensitive and cost-effective method for the simultaneous detection of all Achromobacter spp. and A. xylosoxidans and will facilitate the rapid and accurate diagnosis of this important group of pathogens.
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Affiliation(s)
- Erin P. Price
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Valentina Soler Arango
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Timothy J. Kidd
- School of Chemistry and Molecular Biosciences, Faculty of Science, The University of Queensland, St Lucia, Queensland, Australia
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Tamieka A. Fraser
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
| | - Thuy-Khanh Nguyen
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Scott C. Bell
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Chermside, Queensland, Australia
| | - Derek S. Sarovich
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia
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18
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Burkholderia pseudomallei pathogenesis and survival in different niches. Biochem Soc Trans 2020; 48:569-579. [PMID: 32167134 DOI: 10.1042/bst20190836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 01/16/2023]
Abstract
Burkholderia pseudomallei (Bp) is the causative agent of melioidosis, a disease of the tropics with high clinical mortality rates. To date, no vaccines are approved for melioidosis and current treatment relies on antibiotics. Conversely, common misdiagnosis and high pathogenicity of Bp hamper efforts to fight melioidosis. This bacterium can be isolated from a wide range of niches such as waterlogged fields, stagnant water bodies, salt water bodies and from human and animal clinical specimens. Although extensive studies have been undertaken to elucidate pathogenesis mechanisms of Bp, little is known about how a harmless soil bacterium adapts to different environmental conditions, in particular, the shift to a human host to become a highly virulent pathogen. The bacterium has a large genome encoding an armory of factors that assist the pathogen in surviving under stressful conditions and assuming its role as a deadly intracellular pathogen. This review presents an overview of what is currently known about how the pathogen adapts to different environments. With in-depth understanding of Bp adaptation and survival, more effective therapies for melioidosis can be developed by targeting related genes or proteins that play a major role in the bacteria's survival.
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19
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Pearson T, Sahl JW, Hepp CM, Handady K, Hornstra H, Vazquez AJ, Settles E, Mayo M, Kaestli M, Williamson CHD, Price EP, Sarovich DS, Cook JM, Wolken SR, Bowen RA, Tuanyok A, Foster JT, Drees KP, Kidd TJ, Bell SC, Currie BJ, Keim P. Pathogen to commensal? Longitudinal within-host population dynamics, evolution, and adaptation during a chronic >16-year Burkholderia pseudomallei infection. PLoS Pathog 2020; 16:e1008298. [PMID: 32134991 PMCID: PMC7077878 DOI: 10.1371/journal.ppat.1008298] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 03/17/2020] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.
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Affiliation(s)
- Talima Pearson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jason W. Sahl
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Crystal M. Hepp
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Karthik Handady
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Heidie Hornstra
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Adam J. Vazquez
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erik Settles
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Mark Mayo
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Mirjam Kaestli
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Charles H. D. Williamson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Erin P. Price
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Derek S. Sarovich
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - James M. Cook
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Spenser R. Wolken
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Colorado, United States of America
| | - Apichai Tuanyok
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Jeffrey T. Foster
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Kevin P. Drees
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Timothy J. Kidd
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Scott C. Bell
- Department of Thoracic Medicine, The Prince Charles Hospital, Chermside, and QIMR Berghofer Medical Research Institute, Queensland, Australia
| | - Bart J. Currie
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Infectious Diseases Department and Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Paul Keim
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, United States of America
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20
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Fraser TA, Bell MG, Harris PNA, Bell SC, Bergh H, Nguyen TK, Kidd TJ, Nimmo GR, Sarovich DS, Price EP. Quantitative real-time PCR assay for the rapid identification of the intrinsically multidrug-resistant bacterial pathogen Stenotrophomonas maltophilia. Microb Genom 2019; 5. [PMID: 31617838 PMCID: PMC6861864 DOI: 10.1099/mgen.0.000307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Stenotrophomonas maltophilia is emerging as an important cause of disease in nosocomial and community-acquired settings, including bloodstream, wound and catheter-associated infections. Cystic fibrosis (CF) airways also provide optimal growth conditions for various opportunistic pathogens with high antibiotic tolerance, including S. maltophilia. Currently, there is no rapid, cost-effective and accurate molecular method for detecting this potentially life-threatening pathogen, particularly in polymicrobial specimens, suggesting that its true prevalence is underestimated. Here, we used large-scale comparative genomics to identify a specific genetic target for S. maltophilia, with subsequent development and validation of a real-time PCR assay for its detection. Analysis of 167 Stenotrophomonas spp. genomes identified a conserved 4 kb region in S. maltophilia, which was targeted for Black Hole Quencher assay design. Our assay yielded the positive detection of 89 of 89 (100%) clinical S. maltophilia strains, and no amplification of 23 non-S. maltophilia clinical isolates. S. maltophilia was detected in 10 of 16 CF sputa, demonstrating the assay's utility for direct detection in respiratory specimens. The assay demonstrated good sensitivity, with limits of detection and quantitation on pure culture of ~10 and ~100 genome equivalents, respectively. Our assay provides a highly specific, sensitive and cost-effective method for the accurate identification of S. maltophilia, and will improve the diagnosis and treatment of this under-recognized pathogen by enabling its accurate and rapid detection from polymicrobial clinical and environmental samples.
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Affiliation(s)
- Tamieka A Fraser
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.,GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Mikaela G Bell
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.,GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Patrick N A Harris
- University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.,Microbiology Department, Central Laboratory, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Scott C Bell
- Adult Cystic Fibrosis Centre, Prince Charles Hospital, Chermside, Queensland, Australia.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Haakon Bergh
- Microbiology Department, Central Laboratory, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Thuy-Khanh Nguyen
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, Faculty of Science, University of Queensland, St Lucia, Queensland, Australia.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Graeme R Nimmo
- Microbiology Department, Central Laboratory, Pathology Queensland, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Derek S Sarovich
- Sunshine Coast Health Institute, Birtinya, Queensland, Australia.,GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Erin P Price
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.,Sunshine Coast Health Institute, Birtinya, Queensland, Australia
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21
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Coulon PML, Groleau MC, Déziel E. Potential of the Burkholderia cepacia Complex to Produce 4-Hydroxy-3-Methyl-2-Alkyquinolines. Front Cell Infect Microbiol 2019; 9:33. [PMID: 30873388 PMCID: PMC6403149 DOI: 10.3389/fcimb.2019.00033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/01/2019] [Indexed: 12/22/2022] Open
Abstract
A few Burkholderia species, especially Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia ambifaria, and Burkholderia cepacia, are known to produce and release various 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), a family of molecules analogous to the 4-hydroxy-2-alkylquinolines [aka 2-n-alkyl-4(1H)-quinolones] of Pseudomonas aeruginosa, which include the Pseudomonas quinolone signal (PQS). However, while these exoproducts play several roles in P. aeruginosa virulence and survival, the available literature is very limited on their distribution and function in Burkholderia. In this perspective article, we studied the distribution of the hmqABCDEFG operon, which encodes the enzymes involved in the biosynthesis of HMAQs, in the Burkholderia cepacia complex (Bcc) group. Based on the available sequence data, about one third of Bcc species carry a homolog of the hmqABCDEFG, and not all sequenced strains in a given species possess this operon. Looking at the synteny of genes surrounding the hmqABCDEFG operon, we found that for some species, the operon seems to have been deleted or replaced by other genes. Finally, we review the literature on the possible function of HMAQs. Understanding the Hmq system may provide clues concerning their functions in Bcc.
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Affiliation(s)
- Pauline M L Coulon
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
| | | | - Eric Déziel
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
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22
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Price EP, Sarovich DS. The Scourge of Antibiotic-resistant Infections in Cystic Fibrosis. Trends Microbiol 2019; 27:289-291. [PMID: 30709708 DOI: 10.1016/j.tim.2019.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 01/17/2019] [Indexed: 11/15/2022]
Abstract
Bacterial infections are the primary cause of respiratory decline and mortality in cystic fibrosis (CF) patients. In a recent study, Diaz Caballero and colleagues [1] (PLoS Pathog. 2018;14:e1007453) catalogued the molecular adaptation of a decade-long Burkholderia multivorans infection in a Canadian CF patient, which evolved to become resistant towards multiple classes of antibiotics.
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Affiliation(s)
- Erin P Price
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Sunshine Coast Health Institute, University of the Sunshine Coast, Birtinya, Queensland, Australia.
| | - Derek S Sarovich
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Sunshine Coast Health Institute, University of the Sunshine Coast, Birtinya, Queensland, Australia
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23
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Webb JR, Price EP, Somprasong N, Schweizer HP, Baird RW, Currie BJ, Sarovich DS. Development and validation of a triplex quantitative real-time PCR assay to detect efflux pump-mediated antibiotic resistance in Burkholderia pseudomallei. Future Microbiol 2018; 13:1403-1418. [PMID: 30256166 PMCID: PMC6190177 DOI: 10.2217/fmb-2018-0155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/23/2018] [Indexed: 01/12/2023] Open
Abstract
AIM To develop a probe-based triplex quantitative real-time PCR assay to simultaneously detect the upregulation of the efflux pumps AmrAB-OprA, BpeAB-OprB and BpeEF-OprC in Burkholderia pseudomallei strains exhibiting increased minimum inhibitory concentrations toward meropenem, doxycycline or trimethoprim-sulfamethoxazole. METHODS The triplex assay was developed and subsequently tested on RNA isolated from eight clinical and eight laboratory-generated B. pseudomallei mutants harboring efflux pump regulator mutations. RESULTS The triplex assay accurately detected efflux pump upregulation in all clinical and laboratory mutants, which corresponded with decreased antibiotic susceptibility or antibiotic resistance. CONCLUSION Rapid detection of antibiotic resistance provides clinicians with a tool to identify potential treatment failure in near real time, enabling informed alteration of treatment during an infection and improved patient outcomes.
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Affiliation(s)
- Jessica R Webb
- Global & Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Erin P Price
- Global & Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
| | - Nawarat Somprasong
- Department of Molecular Genetics & Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics & Microbiology, College of Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Robert W Baird
- Departments of Infectious Diseases & Pathology & Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Bart J Currie
- Global & Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Departments of Infectious Diseases & Pathology & Northern Territory Medical Program, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - Derek S Sarovich
- Global & Tropical Health Division, Menzies School of Health Research, Darwin, Northern Territory, Australia
- Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
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