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Singh S, Gola C, Singh B, Agrawal V, Chaba R. D-galactonate metabolism in enteric bacteria: a molecular and physiological perspective. Curr Opin Microbiol 2024; 81:102524. [PMID: 39137493 DOI: 10.1016/j.mib.2024.102524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/31/2024] [Accepted: 07/31/2024] [Indexed: 08/15/2024]
Abstract
D-galactonate, a widely prevalent sugar acid, was first reported as a nutrient source for enteric bacteria in the 1970s. Since then, decades of research enabled a description of the modified Entner-Doudoroff pathway involved in its degradation and reported the structural and biochemical features of its metabolic enzymes, primarily in Escherichia coli K-12. However, only in the last few years, the D-galactonate transporter has been characterized, and the regulation of the dgo operon, encoding the structural genes for the transporter and enzymes of D-galactonate metabolism, has been detailed. Notably, in recent years, multiple evolutionary studies have identified the dgo operon as a dominant target for adaptation of E. coli in the mammalian gut. Despite considerable research on dgo operon, numerous fundamental questions remain to be addressed. The emerging relevance of the dgo operon in host-bacterial interactions further necessitates the study of D-galactonate metabolism in other enterobacterial strains.
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Affiliation(s)
- Swati Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab 140306, India
| | - Chetna Gola
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab 140306, India
| | - Bhupinder Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab 140306, India
| | - Vishal Agrawal
- Amity School of Biological Sciences, Amity University Punjab, Mohali, SAS Nagar, Punjab 140306, India
| | - Rachna Chaba
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab 140306, India.
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2
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Pokorzynski ND, Groisman EA. How Bacterial Pathogens Coordinate Appetite with Virulence. Microbiol Mol Biol Rev 2023; 87:e0019822. [PMID: 37358444 PMCID: PMC10521370 DOI: 10.1128/mmbr.00198-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023] Open
Abstract
Cells adjust growth and metabolism to nutrient availability. Having access to a variety of carbon sources during infection of their animal hosts, facultative intracellular pathogens must efficiently prioritize carbon utilization. Here, we discuss how carbon source controls bacterial virulence, with an emphasis on Salmonella enterica serovar Typhimurium, which causes gastroenteritis in immunocompetent humans and a typhoid-like disease in mice, and propose that virulence factors can regulate carbon source prioritization by modifying cellular physiology. On the one hand, bacterial regulators of carbon metabolism control virulence programs, indicating that pathogenic traits appear in response to carbon source availability. On the other hand, signals controlling virulence regulators may impact carbon source utilization, suggesting that stimuli that bacterial pathogens experience within the host can directly impinge on carbon source prioritization. In addition, pathogen-triggered intestinal inflammation can disrupt the gut microbiota and thus the availability of carbon sources. By coordinating virulence factors with carbon utilization determinants, pathogens adopt metabolic pathways that may not be the most energy efficient because such pathways promote resistance to antimicrobial agents and also because host-imposed deprivation of specific nutrients may hinder the operation of certain pathways. We propose that metabolic prioritization by bacteria underlies the pathogenic outcome of an infection.
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Affiliation(s)
- Nick D. Pokorzynski
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
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3
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A Copper-Responsive Two-Component System Governs Lipoprotein Remodeling in Listeria monocytogenes. J Bacteriol 2023; 205:e0039022. [PMID: 36622228 PMCID: PMC9879112 DOI: 10.1128/jb.00390-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Bacterial lipoproteins are membrane-associated proteins with a characteristic acylated N-terminal cysteine residue anchoring C-terminal globular domains to the membrane surface. While all lipoproteins are modified with acyl chains, the number, length, and position can vary depending on host. The acylation pattern also alters ligand recognition by the Toll-like receptor 2 (TLR2) protein family, a signaling system that is central to bacterial surveillance and innate immunity. In select Listeria monocytogenes isolates carrying certain plasmids, copper exposure converts the lipoprotein chemotype into a weak TLR2 ligand through expression of the enzyme lipoprotein intramolecular acyltransferase (Lit). In this study, we identify the response regulator (CopR) from a heavy metal-sensing two-component system as the transcription factor that integrates external copper levels with lipoprotein structural modifications. We show that phosphorylated CopR controls the expression of three distinct transcripts within the plasmid cassette encoding Lit2, prolipoprotein diacylglyceryl transferase (Lgt2), putative copper resistance determinants, and itself (the CopRS two-component system). CopR recognizes a direct repeat half-site consensus motif (TCTACACA) separated by 3 bp that overlaps the -35 promoter element. Target gene expression and lipoprotein conversion were not observed in the absence of the response regulator, indicating that CopR phosphorylation is the dominant mechanism of regulation. IMPORTANCE Copper is a frontline antimicrobial used to limit bacterial growth in multiple settings. Here, we demonstrate how the response regulator CopR from a plasmid-borne two-component system in the opportunistic pathogen L. monocytogenes directly induces lipoprotein remodeling in tandem with copper resistance genes due to extracellular copper stress. Activation of CopR by phosphorylation converts the lipoprotein chemotype from a high- to low-immunostimulatory TLR2 ligand. The two-component system-mediated coregulation of copper resistance determinants, in tandem with lipoprotein biosynthesis demonstrated here in L. monocytogenes, may be a common feature of transmissible copper resistance cassettes found in other Firmicutes.
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SurA-like and Skp-like Proteins as Important Virulence Determinants of the Gram Negative Bacterial Pathogens. Int J Mol Sci 2022; 24:ijms24010295. [PMID: 36613738 PMCID: PMC9820271 DOI: 10.3390/ijms24010295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
In the Gram-negative bacteria, many important virulence factors reach their destination via two-step export systems, and they must traverse the periplasmic space before reaching the outer membrane. Since these proteins must be maintained in a structure competent for transport into or across the membrane, they frequently require the assistance of chaperones. Based on the results obtained for the model bacterium Escherichia coli and related species, it is assumed that in the biogenesis of the outer membrane proteins and the periplasmic transit of secretory proteins, the SurA peptidyl-prolyl isomerase/chaperone plays a leading role, while the Skp chaperone is rather of secondary importance. However, detailed studies carried out on several other Gram-negative pathogens indicate that the importance of individual chaperones in the folding and transport processes depends on the properties of client proteins and is species-specific. Taking into account the importance of SurA functions in bacterial virulence and severity of phenotypes due to surA mutations, this folding factor is considered as a putative therapeutic target to combat microbial infections. In this review, we present recent findings regarding SurA and Skp proteins: their mechanisms of action, involvement in processes related to virulence, and perspectives to use them as therapeutic targets.
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5
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Dawan J, Ahn J. Variability in Adaptive Resistance of Salmonella Typhimurium to Sublethal Levels of Antibiotics. Antibiotics (Basel) 2022; 11:antibiotics11121725. [PMID: 36551382 PMCID: PMC9774383 DOI: 10.3390/antibiotics11121725] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
This study was designed to evaluate the adaptive resistance of Salmonella Typhimurium under continuous sublethal selective pressure. Salmonella Typhimurium ATCC 19585 (STATCC) and S. Typhimurium CCARM 8009 (STCCARM) were sequentially cultured for 3 days at 37 °C in trypticase soy broth containing 1/2 × MICs of cefotaxime (CEF1/2), chloramphenicol (CHL1/2), gentamicin (GEN1/2), and polymyxin B (POL1/2). The STATCC and STCCARM exposed to CEF1/2, CHL1/2, GEN1/2, and POL1/2 were evaluated using antibiotic susceptibility, cross-resistance, and relative fitness. The susceptibilities of STATCC exposed to GEN1/2 and POL1/2 were increased by a 2-fold (gentamicin) and 8-fold (polymyxin B) increase in minimum inhibitory concentration (MIC) values, respectively. The MIC values of STCCARM exposed to CEF1/2, CHL1/2, GEN1/2, and POL1/2 were increased by 4-fold (cefotaxime), 2-fold (chloramphenicol), 2-fold (gentamicin), and 8-fold (polymyxin B). The highest heterogeneous fractions were observed for the STATCC exposed to CEF1/2 (38%) and POL1/2 (82%). The STCCARM exposed to GEN1/2 was cross-resistant to cefotaxime (p < 0.05), chloramphenicol (p < 0.01), and polymyxin B (p < 0.05). The highest relative fitness levels were 0.92 and 0.96, respectively, in STATCC exposed to CEF1/2 and STCCARM exposed to POL1/2. This study provides new insight into the fate of persistent cells and also guidance for antibiotic use.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Republic of Korea
| | - Juhee Ahn
- Department of Biomedical Science, Kangwon National University, Chuncheon 24341, Gangwon, Republic of Korea
- Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Republic of Korea
- Correspondence: ; Tel.: +82-33-250-6564
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6
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Dombach JL, Quintana JLJ, Allgood SC, Nagy TA, Gustafson DL, Detweiler CS. A small molecule that disrupts S. Typhimurium membrane voltage without cell lysis reduces bacterial colonization of mice. PLoS Pathog 2022; 18:e1010606. [PMID: 35687608 PMCID: PMC9223311 DOI: 10.1371/journal.ppat.1010606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/23/2022] [Accepted: 05/19/2022] [Indexed: 12/24/2022] Open
Abstract
As pathogenic bacteria become increasingly resistant to antibiotics, antimicrobials with mechanisms of action distinct from current clinical antibiotics are needed. Gram-negative bacteria pose a particular problem because they defend themselves against chemicals with a minimally permeable outer membrane and with efflux pumps. During infection, innate immune defense molecules increase bacterial vulnerability to chemicals by permeabilizing the outer membrane and occupying efflux pumps. Therefore, screens for compounds that reduce bacterial colonization of mammalian cells have the potential to reveal unexplored therapeutic avenues. Here we describe a new small molecule, D66, that prevents the survival of a human Gram-negative pathogen in macrophages. D66 inhibits bacterial growth under conditions wherein the bacterial outer membrane or efflux pumps are compromised, but not in standard microbiological media. The compound disrupts voltage across the bacterial inner membrane at concentrations that do not permeabilize the inner membrane or lyse cells. Selection for bacterial clones resistant to D66 activity suggested that outer membrane integrity and efflux are the two major bacterial defense mechanisms against this compound. Treatment of mammalian cells with D66 does not permeabilize the mammalian cell membrane but does cause stress, as revealed by hyperpolarization of mitochondrial membranes. Nevertheless, the compound is tolerated in mice and reduces bacterial tissue load. These data suggest that the inner membrane could be a viable target for anti-Gram-negative antimicrobials, and that disruption of bacterial membrane voltage without lysis is sufficient to enable clearance from the host.
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Affiliation(s)
- Jamie L. Dombach
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
- * E-mail: (JLD); (CSD)
| | - Joaquin LJ Quintana
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Samual C. Allgood
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Toni A. Nagy
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Daniel L. Gustafson
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
- * E-mail: (JLD); (CSD)
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7
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Molecular Characterization of Salmonella Detected along the Broiler Production Chain in Trinidad and Tobago. Microorganisms 2022; 10:microorganisms10030570. [PMID: 35336145 PMCID: PMC8955423 DOI: 10.3390/microorganisms10030570] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 02/04/2023] Open
Abstract
This cross-sectional study determined the serovars, antimicrobial resistance genes, and virulence factors of Salmonella isolated from hatcheries, broiler farms, processing plants, and retail outlets in Trinidad and Tobago. Salmonella in silico serotyping detected 23 different serovars where Kentucky 20.5% (30/146), Javiana 19.2% (28/146), Infantis 13.7% (20/146), and Albany 8.9% (13/146) were the predominant serovars. There was a 76.0% (111/146) agreement between serotyping results using traditional conventional methods and whole-genome sequencing (WGS) in in silico analysis. In silico identification of antimicrobial resistance genes conferring resistance to aminoglycosides, cephalosporins, peptides, sulfonamides, and antiseptics were detected. Multidrug resistance (MDR) was detected in 6.8% (10/146) of the isolates of which 100% originated from broiler farms. Overall, virulence factors associated with secretion systems and fimbrial adherence determinants accounted for 69.3% (3091/4463), and 29.2% (1302/4463) counts, respectively. Ten of 20 isolates of serovar Infantis (50.0%) showed MDR and contained the blaCTX-M-65 gene. This is the first molecular characterization of Salmonella isolates detected along the entire broiler production continuum in the Caribbean region using WGS. The availability of these genomes will help future source tracking during epidemiological investigations associated with Salmonella foodborne outbreaks in the region and worldwide.
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Li P, Zhan LI, Wang H, Gao W, Gao L, Lv S, Zhang X, Zhu G, Yan Y. First Identification and Limited Dissemination of mcr-1 Colistin Resistance in Salmonella Isolates from Jiaxing. J Food Prot 2022; 85:213-219. [PMID: 34648627 DOI: 10.4315/jfp-21-069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 10/09/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Salmonella, a major foodborne pathogen, causes severe gastrointestinal disease in people and animals worldwide. Plasmid-borne mcr-1, which confers colistin resistance in Salmonella, has significant epidemiological interest for public health safety. Here, we report the first evidence of mcr-1-mediated colistin resistance in one multidrug-resistant strain, 16062, from 355 Salmonella isolates collected for Jiaxing foodborne pathogen monitoring in Zhejiang Province from 2015 to 2019. In addition to colistin, 16062 displayed multidrug resistance to various antimicrobials (β-lactams, quinolone, sulfonamide, florfenicol, ampicillin, streptomycin, nalidixic acid, aminoglycoside, and trimethoprim-sulfamethoxazole). The mcr-1-carrying IncX4 plasmid (p16062-MCR) in this study shares a conserved structure with other mcr-IncX4 plasmids. We found that other antimicrobial-resistance genes (aac(6')-Ib-cr, aadA1, aadA2, aph(3')-Ia, oqxA, oqxB, sul1, and cmlA1) are located on p16062-cmlA, an atypical IncHI2 plasmid, in isolate 16062. This is the first identification of transferable colistin resistance in a foodborne Salmonella isolate collected in Jiaxing City, the 5-year monitoring of which revealed limited dissemination. By determining the genetic features of the plasmid vehicle, the characteristics of transferable mcr genes circulating in isolates from Jiaxing are now clearer. HIGHLIGHTS
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Affiliation(s)
- Ping Li
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - L I Zhan
- Institute of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China
| | - Henghui Wang
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Wenjie Gao
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Lei Gao
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Shencong Lv
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Xiaofei Zhang
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Guoying Zhu
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
| | - Yong Yan
- Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, Jiaxing 314050, China; and
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Zhang S, Abbas M, Rehman MU, Wang M, Jia R, Chen S, Liu M, Zhu D, Zhao X, Gao Q, Tian B, Cheng A. Updates on the global dissemination of colistin-resistant Escherichia coli: An emerging threat to public health. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 799:149280. [PMID: 34364270 DOI: 10.1016/j.scitotenv.2021.149280] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/22/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Colistin drug resistance is an emerging public health threat worldwide. The adaptability, existence and spread of colistin drug resistance in multiple reservoirs and ecological environmental settings is significantly increasing the rate of occurrence of multidrug resistant (MDR) bacteria such as Escherichia coli (E. coli). Here, we summarized the reports regarding molecular and biological characterization of mobile colistin resistance gene (mcr)-positive E. coli (MCRPEC), originating from diverse reservoirs, including but not limited to humans, environment, waste water treatment plants, wild, pets, and food producing animals. The MCRPEC revealed the abundance of clinically important resistance genes, which are responsible for MDR profile. A number of plasmid replicon types such as IncI2, IncX4, IncP, IncX, and IncFII with a predominance of IncI2 were facilitating the spread of colistin resistance. This study concludes the distribution of multiple sequence types of E. coli carrying mcr gene variants, which are possible threat to "One Health" perspective. In addition, we have briefly explained the newly known mechanisms of colistin resistance i.e. plasmid-encoded resistance determinant as well as presented the chromosomally-encoded resistance mechanisms. The transposition of ISApl1 into the chromosome and existence of intact Tn6330 are important for transmission and stability for mcr gene. Further, genetic environment of co-localized mcr gene with carbapenem-resistance or extended-spectrum β-lactamases genes has also been elaborated, which is limiting human beings to choose last resort antibiotics. Finally, environmental health and safety control measures along with spread mechanisms of mcr genes are discussed to avoid further propagation and environmental hazards of colistin resistance.
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Affiliation(s)
- Shaqiu Zhang
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Muhammad Abbas
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China; Livestock and Dairy Development Department Lahore, Punjab 54000, Pakistan
| | - Mujeeb Ur Rehman
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China; Disease Investigation Laboratory, Livestock & Dairy Development Department, Zhob 85200, Balochistan, Pakistan
| | - Mingshu Wang
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Renyong Jia
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Shun Chen
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Mafeng Liu
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Dekang Zhu
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Xinxin Zhao
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Qun Gao
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Bin Tian
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China
| | - Anchun Cheng
- Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, PR China.
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10
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de Pina LC, da Silva FSH, Galvão TC, Pauer H, Ferreira RBR, Antunes LCM. The role of two-component regulatory systems in environmental sensing and virulence in Salmonella. Crit Rev Microbiol 2021; 47:397-434. [PMID: 33751923 DOI: 10.1080/1040841x.2021.1895067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Adaptation to environments with constant fluctuations imposes challenges that are only overcome with sophisticated strategies that allow bacteria to perceive environmental conditions and develop an appropriate response. The gastrointestinal environment is a complex ecosystem that is home to trillions of microorganisms. Termed microbiota, this microbial ensemble plays important roles in host health and provides colonization resistance against pathogens, although pathogens have evolved strategies to circumvent this barrier. Among the strategies used by bacteria to monitor their environment, one of the most important are the sensing and signalling machineries of two-component systems (TCSs), which play relevant roles in the behaviour of all bacteria. Salmonella enterica is no exception, and here we present our current understanding of how this important human pathogen uses TCSs as an integral part of its lifestyle. We describe important aspects of these systems, such as the stimuli and responses involved, the processes regulated, and their roles in virulence. We also dissect the genomic organization of histidine kinases and response regulators, as well as the input and output domains for each TCS. Lastly, we explore how these systems may be promising targets for the development of antivirulence therapeutics to combat antibiotic-resistant infections.
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Affiliation(s)
- Lucindo Cardoso de Pina
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Programa de Pós-Graduação em Biociências, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.,Programa de Pós-Graduação Ciência para o Desenvolvimento, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Teca Calcagno Galvão
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Heidi Pauer
- Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil
| | | | - L Caetano M Antunes
- Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.,Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas, Rio de Janeiro, Brazil.,Laboratório de Pesquisa em Infecção Hospitalar, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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11
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Kubicek-Sutherland JZ, Xie G, Shakya M, Dighe PK, Jacobs LL, Daligault H, Davenport K, Stromberg LR, Stromberg ZR, Cheng Q, Kempaiah P, Ong’echa JM, Otieno V, Raballah E, Anyona S, Ouma C, Chain PSG, Perkins DJ, Mukundan H, McMahon BH, Doggett NA. Comparative genomic and phenotypic characterization of invasive non-typhoidal Salmonella isolates from Siaya, Kenya. PLoS Negl Trop Dis 2021; 15:e0008991. [PMID: 33524010 PMCID: PMC7877762 DOI: 10.1371/journal.pntd.0008991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 02/11/2021] [Accepted: 11/17/2020] [Indexed: 02/07/2023] Open
Abstract
Non-typhoidal Salmonella (NTS) is a major global health concern that often causes bloodstream infections in areas of the world affected by malnutrition and comorbidities such as HIV and malaria. Developing a strategy to control the emergence and spread of highly invasive and antimicrobial resistant NTS isolates requires a comprehensive analysis of epidemiological factors and molecular pathogenesis. Here, we characterize 11 NTS isolates that caused bloodstream infections in pediatric patients in Siaya, Kenya from 2003-2010. Nine isolates were identified as S. Typhimurium sequence type 313 while the other two were S. Enteritidis. Comprehensive genotypic and phenotypic analyses were performed to compare these isolates to those previously identified in sub-Saharan Africa. We identified a S. Typhimurium isolate referred to as UGA14 that displayed novel plasmid, pseudogene and resistance features as compared to other isolates reported from Africa. Notably, UGA14 is able to ferment both lactose and sucrose due to the acquisition of insertion elements on the pKST313 plasmid. These findings show for the first time the co-evolution of plasmid-mediated lactose and sucrose metabolism along with cephalosporin resistance in NTS further elucidating the evolutionary mechanisms of invasive NTS phenotypes. These results further support the use of combined genomic and phenotypic approaches to detect and characterize atypical NTS isolates in order to advance biosurveillance efforts that inform countermeasures aimed at controlling invasive and antimicrobial resistant NTS.
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Affiliation(s)
| | - Gary Xie
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
| | - Migun Shakya
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
| | - Priya K. Dighe
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
| | - Lindsey L. Jacobs
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
| | | | - Karen Davenport
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
| | | | | | - Qiuying Cheng
- Center for Global Health, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Prakasha Kempaiah
- Center for Global Health, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - John Michael Ong’echa
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
| | - Vincent Otieno
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
| | - Evans Raballah
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Medical Laboratory Science, School of Public Health, Biomedical Sciences and Technology, Masinde Muliro University of Science and Technology, Kakamega, Kenya
| | - Samuel Anyona
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Medical Biochemistry, School of Medicine, Maseno University, Maseno, Kenya
| | - Collins Ouma
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | | | - Douglas J. Perkins
- Center for Global Health, University of New Mexico, Albuquerque, New Mexico, United States of America
- University of New Mexico/KEMRI Laboratories of Parasitic and Viral Diseases, Kenya Medical Research Institute, Kisumu, Kenya
| | - Harshini Mukundan
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
- * E-mail:
| | | | - Norman A. Doggett
- Los Alamos National Laboratory, Los Alamos, New Mexico, United States
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12
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Arunima A, Swain SK, Ray S, Prusty BK, Suar M. RpoS-regulated SEN1538 gene promotes resistance to stress and influences Salmonella enterica serovar enteritidis virulence. Virulence 2020; 11:295-314. [PMID: 32193977 PMCID: PMC7161692 DOI: 10.1080/21505594.2020.1743540] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Salmonella enterica serovar Enteritidis (S. Enteritidis; wild type (WT)) is a major cause of foodborne illness globally. The ability of this pathogen to survive stress inside and outside the host, such as encountering antimicrobial peptides and heat stress, determines the efficiency of enteric infection. These stressors concertedly trigger virulence factors encoded on Salmonella pathogenicity islands (SPIs). Although RpoS is a well-known central transcriptional stress and virulence regulator, functional information regarding the genes of the regulon is currently limited. Here, we identified SEN1538 as a conserved RpoS-regulated gene belonging to the KGG protein superfamily. We further assessed its role in pathogenic stress responses and virulence. When SEN1538 was deleted (Δ1538), the pathogen showed reduced survival during antimicrobial peptide introduction and heat stress at 55°C compared to WT. The mutant displayed 70% reduced invasion in the HCT116 colon epithelial cell line, 5-fold attenuated phagocytic survival in RAW264.7 cells, and downregulation of several SPI-1 and SPI-2 genes encoding the three secretion system apparatus and effector proteins. Δ1538 also showed decreased virulence compared to WT, demonstrated by its reduced bacterial counts in the feces, mLN, spleen, and cecum of C57BL/6 mice. Comparative transcriptomic analysis of Δ1538 against WT revealed 111 differentially regulated genes, 103 of which were downregulated (fold change ≤ -1.5, P < 0.05). The majority of these genes were in clusters for metabolism, transporters, and pathogenesis, driving pathogenic stress responses and virulence. SEN1538 is, therefore, an important virulence determinant contributing to the resilience of S. Enteritidis to stress factors during infection.
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Affiliation(s)
- Aryashree Arunima
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Sunil Kumar Swain
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Shilpa Ray
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | | | - Mrutyunjay Suar
- School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, India
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13
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Association of Virulence and Antibiotic Resistance in Salmonella-Statistical and Computational Insights into a Selected Set of Clinical Isolates. Microorganisms 2020; 8:microorganisms8101465. [PMID: 32987719 PMCID: PMC7598717 DOI: 10.3390/microorganisms8101465] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 11/16/2022] Open
Abstract
The acquisition of antibiotic resistance (AR) by foodborne pathogens, such as Salmonella enterica, has emerged as a serious public health concern. The relationship between the two key survival mechanisms (i.e., antibiotic resistance and virulence) of bacterial pathogens is complex. However, it is unclear if the presence of certain virulence determinants (i.e., virulence genes) and AR have any association in Salmonella. In this study, we report the prevalence of selected virulence genes and their association with AR in a set of phenotypically tested antibiotic-resistant (n = 117) and antibiotic-susceptible (n = 94) clinical isolates of Salmonella collected from Tennessee, USA. Profiling of virulence genes (i.e., virulotyping) in Salmonella isolates (n = 211) was conducted by targeting 13 known virulence genes and a gene for class 1 integron. The association of the presence/absence of virulence genes in an isolate with their AR phenotypes was determined by the machine learning algorithm Random Forest. The analysis revealed that Salmonella virulotypes with gene clusters consisting of avrA, gipA, sodC1, and sopE1 were strongly associated with any resistant phenotypes. To conclude, the results of this exploratory study shed light on the association of specific virulence genes with drug-resistant phenotypes of Salmonella. The presence of certain virulence genes clusters in resistant isolates may become useful for the risk assessment and management of salmonellosis caused by drug-resistant Salmonella in humans.
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14
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Baindara P, Ghosh AK, Mandal SM. Coevolution of Resistance Against Antimicrobial Peptides. Microb Drug Resist 2020; 26:880-899. [PMID: 32119634 DOI: 10.1089/mdr.2019.0291] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are produced by all forms of life, ranging from eukaryotes to prokaryotes, and they are a crucial component of innate immunity, involved in clearing infection by inhibiting pathogen colonization. In the recent past, AMPs received high attention due to the increase of extensive antibiotic resistance by these pathogens. AMPs exhibit a diverse spectrum of activity against bacteria, fungi, parasites, and various types of cancer. AMPs are active against various bacterial pathogens that cause disease in animals and plants. However, because of the coevolution of host and pathogen interaction, bacteria have developed the mechanisms to sense and exhibit an adaptive response against AMPs. These resistance mechanisms are playing an important role in bacterial virulence within the host. Here, we have discussed the different resistance mechanisms used by gram-positive and gram-negative bacteria to sense and combat AMP actions. Understanding the mechanism of AMP resistance may provide directions toward the development of novel therapeutic strategies to control multidrug-resistant pathogens.
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Affiliation(s)
- Piyush Baindara
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ananta K Ghosh
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Santi M Mandal
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
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15
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Ligowska-Marzęta M, Hancock V, Ingmer H, M Aarestrup F. Comparison of Gene Expression Profiles of Uropathogenic Escherichia Coli CFT073 after Prolonged Exposure to Subinhibitory Concentrations of Different Biocides. Antibiotics (Basel) 2019; 8:antibiotics8040167. [PMID: 31569631 PMCID: PMC6963283 DOI: 10.3390/antibiotics8040167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 01/24/2023] Open
Abstract
Biocides are chemical compounds widely used for sterilization and disinfection. The aim of this study was to examine whether exposure to subinhibitory biocide concentrations influenced transcriptional expression of genes that could improve a pathogen’s drug resistance or fitness. We used DNA microarrays to investigate the transcriptome of the uropathogenic Escherichia coli strain CFT073 in response to prolonged exposure to subinhibitory concentrations of four biocides: benzalkonium chloride, chlorhexidine, hydrogen peroxide and triclosan. Transcription of a gene involved in polymyxin resistance, arnT, was increased after treatment with benzalkonium chloride. However, pretreatment of the bacteria with this biocide did not result in cross-resistance to polymyxin in vitro. Genes encoding products related to transport formed the functional group that was most affected by biocides, as 110 out of 884 genes in this category displayed altered transcription. Transcripts of genes involved in cysteine uptake, sulfate assimilation, dipeptide transport, as well as cryptic phage genes were also more abundant in response to several biocides. Additionally, we identified groups of genes with transcription changes unique to single biocides that might include potential targets for the biocides. The biocides did not increase the resistance potential of the pathogen to other antimicrobials.
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Affiliation(s)
- Małgorzata Ligowska-Marzęta
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, 2300 Copenhagen, Denmark.
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | - Viktoria Hancock
- Renal Research & Innovation, Baxter International Inc., SE-220 10 Lund, Sweden.
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark.
| | - Frank M Aarestrup
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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16
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Song J, Hou HM, Wu HY, Li KX, Wang Y, Zhou QQ, Zhang GL. Transcriptomic Analysis of Vibrio parahaemolyticus Reveals Different Virulence Gene Expression in Response to Benzyl Isothiocyanate. Molecules 2019; 24:molecules24040761. [PMID: 30791538 PMCID: PMC6412943 DOI: 10.3390/molecules24040761] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/13/2019] [Accepted: 02/19/2019] [Indexed: 01/01/2023] Open
Abstract
Vibrio parahaemolyticus isolated from seafood is a pathogenic microorganism that leads to several acute diseases that are harmful to our health and is frequently transmitted by food. Therefore, there is an urgent need for the control and suppression of this pathogen. In this paper, transcriptional analysis was used to determine the effect of treatment with benzyl isothiocyanate (BITC) extracted from cruciferous vegetables on V. parahaemolyticus and to elucidate the molecular mechanisms underlying the response to BITC. Treatment with BITC resulted in 332 differentially expressed genes, among which 137 genes were downregulated, while 195 genes were upregulated. Moreover, six differentially expressed genes (DEGs) in RNA sequencing studies were further verified by quantitative real-time polymerase chain reaction (qRT-PCR). Genes found to regulate virulence encoded an l-threonine 3-dehydrogenase, a GGDEF family protein, the outer membrane protein OmpV, a flagellum-specific adenosine triphosphate synthase, TolQ protein and VirK protein. Hence, the results allow us to speculate that BITC may be an effective control strategy for inhibiting microorganisms growing in foods.
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Affiliation(s)
- Jie Song
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
| | - Hong-Man Hou
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
| | - Hong-Yan Wu
- Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan.
| | - Ke-Xin Li
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
| | - Yan Wang
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
| | - Qian-Qian Zhou
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
| | - Gong-Liang Zhang
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.
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17
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Molecular mechanisms of polymyxin resistance and detection of mcr genes. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2018; 163:28-38. [PMID: 30439931 DOI: 10.5507/bp.2018.070] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/26/2018] [Indexed: 12/12/2022] Open
Abstract
Antibiotic resistance is an ever-increasing global problem. Major commercial antibiotics often fail to fight common bacteria, and some pathogens have become multi-resistant. Polymyxins are potent bactericidal antibiotics against gram-negative bacteria. Known resistance to polymyxin includes intrinsic, mutational and adaptive mechanisms, with the recently described horizontally acquired resistance mechanisms. In this review, we present several strategies for bacteria to develop enhanced resistance to polymyxins, focusing on changes in the outer membrane, efflux and other resistance determinants. Better understanding of the genes involved in polymyxin resistance may pave the way for the development of new and effective antimicrobial agents. We also report novel in silico tested primers for PCR assay that may be able distinguish colistin-resistant isolates carrying the plasmid-encoded mcr genes and will assist in combating the spread of colistin resistance in bacteria.
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18
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Bell EW, Zheng EJ, Ryno LM. Identification of inhibitors of the E. coli chaperone SurA using in silico and in vitro techniques. Bioorg Med Chem Lett 2018; 28:3540-3548. [PMID: 30301675 DOI: 10.1016/j.bmcl.2018.09.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 11/15/2022]
Abstract
SurA is a gram-negative, periplasmic chaperone protein involved in the proper folding of outer membrane porins (OMPs), which protect bacteria against toxins in the extracellular environment by selectively regulating the passage of nutrients into the cell. Previous studies demonstrated that deletion of SurA renders bacteria more sensitive to toxins that compromise the integrity of the outer membrane. Inhibitors of SurA will perturb the folding of OMPs, leading to disruption of the outer membrane barrier and making the cell more vulnerable to toxic insults. The discovery of novel SurA inhibitors is therefore of great importance for developing alternative strategies to overcome antibiotic resistance. Our laboratory has screened over 10,000,000 compoundsin silicoby computationally docking these compounds onto the crystal structure of SurA. Through this screen and a screen of fragment compounds (molecular weight less than 250 g/mol), we found twelve commercially readily available candidate compounds that bind to the putative client binding site of SurA. We confirmed binding to SurA by developing and employing a competitive fluorescence anisotropy-based binding assay. Our results show that one of these compounds, Fmoc-β-(2-quinolyl)-d-alanine, binds the client binding site with high micromolar affinity. Using this compound as a lead, we also discovered that Fmoc-l-tryptophan and Fmoc-l-phenylalanine, but not Fmoc-l-tyrosine, bind SurA with similar micromolar affinity. To our knowledge, this is the first report of a competitive fluorescence anisotropy assay developed for the identification of inhibitors of the chaperone SurA, and the identification of three small molecules that bind SurA at its client binding site.
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Affiliation(s)
- Eric W Bell
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States
| | - Erica J Zheng
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States
| | - Lisa M Ryno
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland St. A263, Oberlin, OH 44074, United States.
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19
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Ben Hamed S, Tavares Ranzani-Paiva MJ, Tachibana L, de Carla Dias D, Ishikawa CM, Esteban MA. Fish pathogen bacteria: Adhesion, parameters influencing virulence and interaction with host cells. FISH & SHELLFISH IMMUNOLOGY 2018; 80:550-562. [PMID: 29966687 DOI: 10.1016/j.fsi.2018.06.053] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/04/2018] [Accepted: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Wild fisheries are declining due to over-fishing, climate change, pollution and marine habitat destructions among other factors, and, concomitantly, aquaculture is increasing significantly around the world. Fish infections caused by pathogenic bacteria are quite common in aquaculture, although their seriousness depends on the season. Drug-supplemented feeds are often used to keep farmed fish free from the diseases caused by such bacteria. However, given that bacteria can survive well in aquatic environments independently of their hosts, bacterial diseases have become major impediments to aquaculture development. On the other hand, the indiscriminate uses of antimicrobial agents has led to resistant strains and the need to switch to other antibiotics, although it seems that an integrated approach that considers not only the pathogen but also the host and the environment will be the most effective method in the long-term to improve aquatic animal health. This review covers the mechanisms of bacterial pathogenicity and details the foundations underlying the interactions occurring between pathogenic bacteria and the fish host in the aquatic environment, as well as the factors that influence virulence. Understanding and linking the different phenomena that occur from adhesion to colonization of the host will offer novel and useful means to help design suitable therapeutic strategies for disease prevention and treatment.
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Affiliation(s)
- Said Ben Hamed
- Fishery Institute-APTA - SAA, Research Center of Aquaculture, Av. Francisco Matarazzo, 455, CEP. 05001-900, Sao Paulo, SP, Brazil
| | - Maria José Tavares Ranzani-Paiva
- Fishery Institute-APTA - SAA, Research Center of Aquaculture, Av. Francisco Matarazzo, 455, CEP. 05001-900, Sao Paulo, SP, Brazil
| | - Leonardo Tachibana
- Fishery Institute-APTA - SAA, Research Center of Aquaculture, Av. Francisco Matarazzo, 455, CEP. 05001-900, Sao Paulo, SP, Brazil
| | - Danielle de Carla Dias
- Fishery Institute-APTA - SAA, Research Center of Aquaculture, Av. Francisco Matarazzo, 455, CEP. 05001-900, Sao Paulo, SP, Brazil
| | - Carlos Massatoshi Ishikawa
- Fishery Institute-APTA - SAA, Research Center of Aquaculture, Av. Francisco Matarazzo, 455, CEP. 05001-900, Sao Paulo, SP, Brazil
| | - María Angeles Esteban
- Fish Innate Immune System Group, Department of Cell Biology & Histology, Faculty of Biology, Regional Campus of International Excellence, ''Campus Mare Nostrum'', University of Murcia, 30100, Murcia, Spain.
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Salmonella Tol-Pal Reduces Outer Membrane Glycerophospholipid Levels for Envelope Homeostasis and Survival during Bacteremia. Infect Immun 2018; 86:IAI.00173-18. [PMID: 29735519 PMCID: PMC6013679 DOI: 10.1128/iai.00173-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
Abstract
Salmonellae regulate membrane lipids during infection, but the exact proteins and mechanisms that promote their survival during bacteremia remain largely unknown. Mutations in genes encoding the conserved Salmonella enterica serovar Typhimurium (S. Typhimurium) Tol-Pal apparatus caused the outer membrane (OM) sensor lipoprotein, RcsF, to become activated. The capsule activation phenotype for the mutants suggested that Tol-Pal might influence envelope lipid homeostasis. The mechanism involves reducing OM glycerophospholipid (GPL) levels, since the mutant salmonellae similarly accumulated phosphatidylglycerols (PGl) and phosphatidylethanolamines (PE) within the OM in comparison to the wild type. The data support the Escherichia coli model, whereby Tol-Pal directs retrograde GPL translocation across the periplasm. The S. Typhimurium mechanism involves contributions from YbgC, a cytoplasmic acyl coenzyme A (acyl-CoA) thioesterase, and CpoB, a periplasmic TolA-binding protein. The functional relationship between Tol-Pal and YbgC and CpoB was previously unresolved. The S. Typhimurium Tol-Pal proteins contribute similarly toward promoting OM-GPL homeostasis and Rcs signaling inactivity but differently toward promoting bacterial morphology, rifampin resistance, survival in macrophages, and survival in mice. For example, tolQ, tolR, tolA, and cpoB mutants were significantly more attenuated than ybgC, tolB, and pal mutants in a systemic mouse model of disease. Therefore, key roles exist for TolQ, TolR, TolA, and CpoB during murine bacteremia, which are independent of maintaining GPL homeostasis. The ability of TolQR to channel protons across the inner membrane (IM) is necessary for S. Typhimurium TolQRA function, since mutating conserved channel-facing residues rendered TolQ ineffective at rescuing deletion mutant phenotypes. Therefore, Tol-Pal promotes S. Typhimurium survival during bacteremia, in part, by reducing OM GPL concentrations, while TolQRA and CpoB enhance systemic virulence by additional mechanisms.
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21
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Wei W, Srinivas S, Lin J, Tang Z, Wang S, Ullah S, Kota VG, Feng Y. Defining ICR-Mo, an intrinsic colistin resistance determinant from Moraxella osloensis. PLoS Genet 2018; 14:e1007389. [PMID: 29758020 PMCID: PMC5983563 DOI: 10.1371/journal.pgen.1007389] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/01/2018] [Accepted: 05/02/2018] [Indexed: 11/19/2022] Open
Abstract
Polymyxin is the last line of defense against severe infections caused by carbapenem-resistant gram-negative pathogens. The emergence of transferable MCR-1/2 polymyxin resistance greatly challenges the renewed interest in colistin (polymyxin E) for clinical treatments. Recent studies have suggested that Moraxella species are a putative reservoir for MCR-1/2 genetic determinants. Here, we report the functional definition of ICR-Mo from M. osloensis, a chromosomally encoded determinant of colistin resistance, in close relation to current MCR-1/2 family. ICR-Mo transmembrane protein was prepared and purified to homogeneity. Taken along with an in vitro enzymatic detection, MALDI-TOF mass spectrometry of bacterial lipid A pools determined that the ICR-Mo enzyme might exploit a possible "ping-pong" mechanism to accept the phosphoethanolamine (PEA) moiety from its donor phosphatidylethanolamine (PE) and then transfer it to the 1(or 4')-phosphate position of lipid A via an ICR-Mo-bound PEA adduct. Structural decoration of LPS-lipid A by ICR-Mo renders the recipient strain of E. coli resistant to polymyxin. Domain swapping assays indicate that the two domains of ICR-Mo cannot be functionally-exchanged with its counterparts in MCR-1/2 and EptA, validating its phylogenetic position in a distinct set of MCR-like genes. Structure-guided functional mapping of ICR-Mo reveals a PE lipid substrate recognizing cavity having a role in enzymatic catalysis and the resultant conference of antibiotic resistance. Expression of icr-Mo in E. coli significantly prevents the formation of reactive oxygen species (ROS) induced by colistin. Taken together, our results define a member of a group of intrinsic colistin resistance genes phylogenetically close to the MCR-1/2 family, highlighting the evolution of transferable colistin resistance.
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Affiliation(s)
- Wenhui Wei
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Swaminath Srinivas
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Illinois, United States of America
| | - Jingxia Lin
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zichen Tang
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shihua Wang
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Saif Ullah
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Vishnu Goutham Kota
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Youjun Feng
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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22
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Xu Y, Wei W, Lei S, Lin J, Srinivas S, Feng Y. An Evolutionarily Conserved Mechanism for Intrinsic and Transferable Polymyxin Resistance. mBio 2018; 9:e02317-17. [PMID: 29636432 PMCID: PMC5893884 DOI: 10.1128/mbio.02317-17] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/08/2018] [Indexed: 12/30/2022] Open
Abstract
Polymyxins, a family of cationic antimicrobial cyclic peptides, act as a last line of defense against severe infections by Gram-negative pathogens with carbapenem resistance. In addition to the intrinsic resistance to polymyxin E (colistin) conferred by Neisseria eptA, the plasmid-borne mobilized colistin resistance gene mcr-1 has been disseminated globally since the first discovery in Southern China, in late 2015. However, the molecular mechanisms for both intrinsic and transferable resistance to colistin remain largely unknown. Here, we aim to address this gap in the knowledge of these proteins. Structural and functional analyses of EptA and MCR-1 and -2 have defined a conserved 12-residue cavity that is required for the entry of the lipid substrate, phosphatidylethanolamine (PE). The in vitro and in vivo data together have allowed us to visualize the similarities in catalytic activity shared by EptA and MCR-1 and -2. The expression of either EptA or MCR-1 or -2 is shown to remodel the surface of enteric bacteria (e.g., Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, etc.), rendering them resistant to colistin. The parallels in the PE substrate-binding cavities among EptA, MCR-1, and MCR-2 provide a comprehensive understanding of both intrinsic and transferable colistin resistance. Domain swapping between EptA and MCR-1 and -2 reveals that the two domains (transmembrane [TM] region and phosphoethanolamine [PEA] transferase) are not functionally exchangeable. Taken together, the results represent a common mechanism for intrinsic and transferable PEA resistance to polymyxin, a last-resort antibiotic against multidrug-resistant pathogens.IMPORTANCE EptA and MCR-1 and -2 remodel the outer membrane, rendering bacteria resistant to colistin, a final resort against carbapenem-resistant pathogens. Structural and functional analyses of EptA and MCR-1 and -2 reveal parallel PE lipid substrate-recognizing cavities, which explains intrinsic and transferable colistin resistance in gut bacteria. A similar mechanism is proposed for the catalytic activities of EptA and MCR-1 and -2. Together, they constitute a common mechanism for intrinsic and transferable polymyxin resistance.
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Affiliation(s)
- Yongchang Xu
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Wenhui Wei
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Sheng Lei
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jingxia Lin
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Swaminath Srinivas
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Youjun Feng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Abstract
Antibiotic resistance has become a global public health priority. Polymyxins, a family of cationic polypeptide antibiotics, act as a final line of refuge against severe infections by Gram-negative pathogens with pan-drug resistance. Unfortunately, this last-resort antibiotic has been challenged by the emergence and global spread of mobilized colistin resistance determinants (mcr). Given the fact that it has triggered extensive concerns worldwide, we present here an updated view of MCR-like colistin resistance. These studies provide a basic framework for understanding the molecular epidemiology and resistance mechanism of MCR-like genes. However, further large-scale epidemiology and functional studies are urgently needed to better understand the biology of this clinically important antibiotic resistance.
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Affiliation(s)
- Jian Sun
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China; These authors contributed equally to this work
| | - Huimin Zhang
- Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou 310058, China; These authors contributed equally to this work
| | - Ya-Hong Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China.
| | - Youjun Feng
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou 510642, China; Department of Medical Microbiology & Parasitology, Zhejiang University School of Medicine, Hangzhou 310058, China; College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China.
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Milton ME, Allen CL, Feldmann EA, Bobay BG, Jung DK, Stephens MD, Melander RJ, Theisen KE, Zeng D, Thompson RJ, Melander C, Cavanagh J. Structure of the Francisella response regulator QseB receiver domain, and characterization of QseB inhibition by antibiofilm 2-aminoimidazole-based compounds. Mol Microbiol 2017; 106:223-235. [PMID: 28755524 DOI: 10.1111/mmi.13759] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2017] [Indexed: 11/29/2022]
Abstract
With antibiotic resistance increasing at alarming rates, targets for new antimicrobial therapies must be identified. A particularly promising target is the bacterial two-component system. Two-component systems allow bacteria to detect, evaluate and protect themselves against changes in the environment, such as exposure to antibiotics and also to trigger production of virulence factors. Drugs that target the response regulator portion of two-component systems represent a potent new approach so far unexploited. Here, we focus efforts on the highly virulent bacterium Francisella tularensis tularensis. Francisella contains only three response regulators, making it an ideal system to study. In this study, we initially present the structure of the N-terminal domain of QseB, the response regulator responsible for biofilm formation. Subsequently, using binding assays, computational docking and cellular studies, we show that QseB interacts with2-aminoimidazole based compounds that impede its function. This information will assist in tailoring compounds to act as adjuvants that will enhance the effect of antibiotics.
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Affiliation(s)
| | - C Leigh Allen
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Erik A Feldmann
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Benjamin G Bobay
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - David K Jung
- Agile Sciences, Keystone Science Center, 1791 Varsity Dr #150, Raleigh, NC 27606, USA
| | - Matthew D Stephens
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - Roberta J Melander
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - Kelly E Theisen
- Department of Structural and Molecular Biochemistry, North Carolina State University, Campus Box 7622, 128 Polk Hall, Raleigh, NC 27695, USA
| | - Daina Zeng
- Agile Sciences, Keystone Science Center, 1791 Varsity Dr #150, Raleigh, NC 27606, USA
| | | | - Christian Melander
- Department of Chemistry, North Carolina State University, Campus Box 8204, 2620 Yarborough Drive, Raleigh, NC 27695, USA
| | - John Cavanagh
- RTI International, 3040 Cornwallis Rd, RTP, NC 27709, USA
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Wang Q, Sun J, Li J, Ding Y, Li XP, Lin J, Hassan B, Feng Y. Expanding landscapes of the diversified mcr-1-bearing plasmid reservoirs. MICROBIOME 2017; 5:70. [PMID: 28683827 PMCID: PMC5500976 DOI: 10.1186/s40168-017-0288-0] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Polymyxin is a cationic polypeptide antibiotic that can disrupt bacterial cell membrane by interacting with its lipopolysaccharide molecules and is used as a last resort drug against lethal infections by the carbapenem-resistant superbugs (like NDM-1). However, global discovery of the MCR-1 colistin resistance dramatically challenges the newly renewed interest in colistin for clinical use. METHODS The mcr-1-harboring plasmids were acquired from swine and human Escherichia coli isolated in China, from 2015 to 2016, and subjected to Illumina PacBio RSII and Hi-Seq2000 for full genome sequencing. PCR was applied to close the gap of the assembled contigs. Ori-Finder was employed to predict the replication origin (oriC) in plasmids. The phenotype of MCR-1-producing isolates was evaluated on the LBA plates with various level of colistin. Genetic deletion was used to test the requirement of the initial "ATG" codon for the MCR-1 function. RESULTS Here, we report full genomes of over 10 mcr-1-harboring plasmids with diversified replication incompatibilities. A novel hybrid IncI2/IncFIB plasmid pGD17-2 was discovered and characterized from a swine isolate with colistin resistance. Intriguingly, co-occurrence of two unique mcr-1-bearing plasmids (pGD65-3, IncI2, and pGD65-5, IncX4) was detected in a single isolate GD65, which might accelerate dissemination of the mcr-1 under environmental selection pressure. Genetic analyses of these plasmids mapped mobile elements in the context of antibiotic resistance and determined two insertion sequences (ISEcp1 and ISApl1) that are responsible for the mobilization of mcr-1. Gene deletion also proved that the first ATG codon is redundant in the mcr-1 gene. CONCLUSIONS Collectively, our results extend landscapes of the diversified mcr-1-bearing plasmid reservoirs.
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Affiliation(s)
- Qingjing Wang
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China
| | - Jian Sun
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Jun Li
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, China
| | - Youfa Ding
- Lishui People's Hospital, Lishui, 323000, Zhejiang, China
| | - Xing-Ping Li
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Jingxia Lin
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China
| | | | - Youjun Feng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China.
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Weirich J, Bräutigam C, Mühlenkamp M, Franz-Wachtel M, Macek B, Meuskens I, Skurnik M, Leskinen K, Bohn E, Autenrieth I, Schütz M. Identifying components required for OMP biogenesis as novel targets for antiinfective drugs. Virulence 2017; 8:1170-1188. [PMID: 28118090 PMCID: PMC5711350 DOI: 10.1080/21505594.2016.1278333] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The emergence of multiresistant Gram-negative bacteria requires new therapies for combating bacterial infections. Targeting the biogenesis of virulence factors could be an alternative strategy instead of killing bacteria with antibiotics. The outer membrane (OM) of Gram-negative bacteria acts as a physical barrier. At the same time it facilitates the exchange of molecules and harbors a multitude of proteins associated with virulence. In order to insert proteins into the OM, an essential oligomeric membrane-associated protein complex, the ß-barrel assembly machinery (BAM) is required. Being essential for the biogenesis of outer membrane proteins (OMPs) the BAM and also periplasmic chaperones may serve as attractive targets to develop novel antiinfective agents. Herein, we aimed to elucidate which proteins belonging to the OMP biogenesis machinery have the most important function in granting bacterial fitness, OM barrier function, facilitating biogenesis of dedicated virulence factors and determination of overall virulence. To this end we used the enteropathogen Yersinia enterocolitica as a model system. We individually knocked out all non-essential components of the BAM (BamB, C and E) as well as the periplasmic chaperones DegP, SurA and Skp. In summary, we found that the most profound phenotypes were produced by the loss of BamB or SurA with both knockouts resulting in significant attenuation or even avirulence of Ye in a mouse infection model. Thus, we assume that both BamB and SurA are promising targets for the development of new antiinfective drugs in the future.
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Affiliation(s)
- Johanna Weirich
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Cornelia Bräutigam
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Melanie Mühlenkamp
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | | | - Boris Macek
- b Proteome Center Tübingen, Universität Tübingen , Tübingen , Germany
| | - Ina Meuskens
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Mikael Skurnik
- c Department of Bacteriology and Immunology , Medicum, Research Programs Unit, Immunobiology Research Program, University of Helsinki , Helsinki , Finland
| | - Katarzyna Leskinen
- c Department of Bacteriology and Immunology , Medicum, Research Programs Unit, Immunobiology Research Program, University of Helsinki , Helsinki , Finland
| | - Erwin Bohn
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Ingo Autenrieth
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Monika Schütz
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
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27
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Andersson D, Hughes D, Kubicek-Sutherland J. Mechanisms and consequences of bacterial resistance to antimicrobial peptides. Drug Resist Updat 2016; 26:43-57. [DOI: 10.1016/j.drup.2016.04.002] [Citation(s) in RCA: 319] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 10/21/2022]
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28
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Survival protein A is essential for virulence in Yersinia pestis. Microb Pathog 2016; 92:50-53. [DOI: 10.1016/j.micpath.2015.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/18/2015] [Accepted: 12/22/2015] [Indexed: 01/13/2023]
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29
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A PmrB-Regulated Deacetylase Required for Lipid A Modification and Polymyxin Resistance in Acinetobacter baumannii. Antimicrob Agents Chemother 2015; 59:7911-4. [PMID: 26459891 DOI: 10.1128/aac.00515-15] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 10/03/2015] [Indexed: 11/20/2022] Open
Abstract
Emerging resistance to "last-resort" polymyxin antibiotics in Gram-negative bacteria is a significant threat to public health. We identified the Acinetobacter baumannii NaxD deacetylase as a critical mediator of lipid A modification resulting in polymyxin resistance and demonstrated that naxD is regulated by the sensor kinase PmrB. This represents the first description of a specific PmrB-regulated gene contributing to polymyxin resistance in A. baumannii and highlights NaxD as a putative drug target to reverse polymyxin resistance.
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30
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Santos CA, Janissen R, Toledo MAS, Beloti LL, Azzoni AR, Cotta MA, Souza AP. Characterization of the TolB-Pal trans-envelope complex from Xylella fastidiosa reveals a dynamic and coordinated protein expression profile during the biofilm development process. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1372-81. [PMID: 26049080 DOI: 10.1016/j.bbapap.2015.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/22/2015] [Accepted: 05/28/2015] [Indexed: 01/09/2023]
Abstract
The intriguing roles of the bacterial Tol-Pal trans-envelope protein complex range from maintenance of cell envelope integrity to potential participation in the process of cell division. In this study, we report the characterization of the XfTolB and XfPal proteins of the Tol-Pal complex of Xylella fastidiosa. X. fastidiosa is a major plant pathogen that forms biofilms inside xylem vessels, triggering the development of diseases in important cultivable plants around the word. Based on functional complementation experiments in Escherichia coli tolB and pal mutant strains, we confirmed the role of xftolB and xfpal in outer membrane integrity. In addition, we observed a dynamic and coordinated protein expression profile during the X. fastidiosa biofilm development process. Using small-angle X-ray scattering (SAXS), the low-resolution structure of the isolated XfTolB-XfPal complex in solution was solved for the first time. Finally, the localization of the XfTolB and XfPal polar ends was visualized via immunofluorescence labeling in vivo during bacterial cell growth. Our results highlight the major role of the components of the cell envelope, particularly the TolB-Pal complex, during the different phases of bacterial biofilm development.
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Affiliation(s)
- Clelton A Santos
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Richard Janissen
- Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Marcelo A S Toledo
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Lilian L Beloti
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Adriano R Azzoni
- Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Monica A Cotta
- Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Anete P Souza
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil; Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
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31
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Antimicrobial peptide resistance in Neisseria meningitidis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:3026-31. [PMID: 26002321 DOI: 10.1016/j.bbamem.2015.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 12/26/2022]
Abstract
Antimicrobial peptides (AMPs) play an important role as a host defense against microbial pathogens and are key components of the human innate immune response. Neisseria meningitidis frequently colonizes the human nasopharynx as a commensal but also is a worldwide cause of epidemic meningitis and rapidly fatal sepsis. In the human respiratory tract, the only known reservoir of N. meningitidis, meningococci are exposed to human endogenous AMPs. Thus, it is not surprising that meningococci have evolved effective mechanisms to confer intrinsic and high levels of resistance to the action of AMPs. This article reviews the current knowledge about AMP resistance mechanisms employed by N. meningitidis. Two major resistance mechanisms employed by meningococci are the constitutive modification of the lipid A head groups of lipooligosaccharides by phosphoethanolamine and the active efflux pump mediated excretion of AMPs. Other factors influencing AMP resistance, such as the major porin PorB, the pilin biogenesis apparatus, and capsular polysaccharides, have also been identified. Even with an inherently high intrinsic resistance, several AMP resistance determinants can be further induced upon exposure to AMPs. Many well-characterized AMP resistance mechanisms in other Gram-negative bacteria are not found in meningococci. Thus, N. meningitidis utilizes a limited but highly effective set of molecular mechanisms to mediate antimicrobial peptide resistance. This article is part of a Special Issue entitled: Bacterial Resistance to Antimicrobial Peptides.
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The Vibrio cholerae VprA-VprB two-component system controls virulence through endotoxin modification. mBio 2014; 5:mBio.02283-14. [PMID: 25538196 PMCID: PMC4278540 DOI: 10.1128/mbio.02283-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The bacterial cell surface is the first structure the host immune system targets to prevent infection. Cationic antimicrobial peptides of the innate immune system bind to the membrane of Gram-negative pathogens via conserved, surface-exposed lipopolysaccharide (LPS) molecules. We recently reported that modern strains of the global intestinal pathogen Vibrio cholerae modify the anionic lipid A domain of LPS with a novel moiety, amino acids. Remarkably, glycine or diglycine addition to lipid A alters the surface charge of the bacteria to help evade the cationic antimicrobial peptide polymyxin. However, the regulatory mechanisms of lipid A modification in V. cholerae are unknown. Here, we identify a novel two-component system that regulates lipid A glycine modification by responding to important biological cues associated with pathogenesis, including bile, mildly acidic pH, and cationic antimicrobial peptides. The histidine kinase Vc1319 (VprB) and the response regulator Vc1320 (VprA) respond to these signals and are required for the expression of the almEFG operon that encodes the genes essential for glycine modification of lipid A. Importantly, both the newly identified two-component system and the lipid A modification machinery are required for colonization of the mammalian host. This study demonstrates how V. cholerae uses a previously unknown regulatory network, independent of well-studied V. cholerae virulence factors and regulators, to respond to the host environment and cause infection. Vibrio cholerae, the etiological agent of cholera disease, infects millions of people every year. V. cholerae El Tor and classical biotypes have been responsible for all cholera pandemics. The El Tor biotype responsible for the current seventh pandemic has displaced the classical biotype worldwide and is highly resistant to cationic antimicrobial peptides, like polymyxin B. This resistance arises from the attachment of one or two glycine residues to the lipid A domain of lipopolysaccharide, a major surface component of Gram-negative bacteria. Here, we identify the VprAB two-component system that regulates the charge of the bacterial surface by directly controlling the expression of genes required for glycine addition to lipid A. The VprAB-dependent lipid A modification confers polymyxin B resistance and contributes significantly to pathogenesis. This finding is relevant for understanding how Vibrio cholerae has evolved mechanisms to facilitate the evasion of the host immune system and increase bacterial fitness.
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Host hydrogen rather than that produced by the pathogen is important for Salmonella enterica serovar Typhimurium virulence. Infect Immun 2014; 83:311-6. [PMID: 25368112 DOI: 10.1128/iai.02611-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium utilizes molecular hydrogen as a substrate in various respiratory pathways, via H2-uptake enzymes termed Hya, Hyb, and Hyd. A different hydrogenase, the hydrogen-evolving Hyc enzyme, removes excess reductant during fermentative growth. Virulence phenotypes conferred by mutations in hyc genes, either alone or in combination with mutations in the H2-uptake enzyme genes, are addressed. Anaerobically grown ΔhycB or ΔhycC single-deletion strains were more sensitive to acid than the wild-type strain, but the Δhyc strains were like the virulent parent strain with respect to both mouse morbidity and mortality and in organ burden numbers. Even fecal-recovery numbers for both mutant strains at several time points prior to the animals succumbing to salmonellosis were like those seen with the parent. Neither hydrogen uptake nor evolution of the gas was detected in a hydrogenase quadruple-mutant strain containing deletions in the hya, hyb, hyd, and hyc genes. As previously described, a strain lacking all H2-uptake ability was severely attenuated in its virulence characteristics, and the quadruple-mutant strain had the same (greatly attenuated) phenotype. While H2 levels were greatly reduced in ceca of mice treated with antibiotics, both the ΔhycB and ΔhycC strains were still like the parent in their ability to cause typhoid salmonellosis. It seems that the level of H2 produced by the pathogen (through formate hydrogen lyase [FHL] and Hyc) is insignificant in terms of providing respiratory reductant to facilitate either organ colonization or contributions to gut growth leading to pathogenesis.
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Lamichhane-Khadka R, Benoit SL, Maier SE, Maier RJ. A link between gut community metabolism and pathogenesis: molecular hydrogen-stimulated glucarate catabolism aids Salmonella virulence. Open Biol 2013; 3:130146. [PMID: 24307595 PMCID: PMC3877842 DOI: 10.1098/rsob.130146] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Glucarate, an oxidized product of glucose, is a major serum organic acid in humans. Still, its role as a carbon source for a pathogen colonizing hosts has not been studied. We detected high-level expression of a potential glucarate permease encoding gene gudT when Salmonella enterica serovar Typhimurium are exposed to hydrogen gas (H2), a gaseous by-product of gut commensal metabolism. A gudT strain of Salmonella is deficient in glucarate-dependent growth, however, it can still use other monosaccharides, such as glucose or galactose. Complementation of the gudT mutant with a plasmid harbouring gudT restored glucarate-dependent growth to wild-type (WT) levels. The gudT mutant exhibits attenuated virulence: the mean time of death for mice inoculated with WT strain was 2 days earlier than for mice inoculated with the gudT strain. At 4 days postinoculation, liver and spleen homogenates from mice inoculated with a gudT strain contained significantly fewer viable Salmonella than homogenates from animals inoculated with the parent. The parent strain grew well H2-dependently in a minimal medium with amino acids and glucarate provided as the sole carbon sources, whereas the gudT strain achieved approximately 30% of the parent strain's yield. Glucarate-mediated growth of a mutant strain unable to produce H2 was stimulated by H2 addition, presumably owing to the positive transcriptional response to H2. Gut microbiota-produced molecular hydrogen apparently signals Salmonella to catabolize an alternative carbon source available in the host. Our results link a gut microbiome-produced diffusible metabolite to augmenting bacterial pathogenesis.
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Strong cross-system interactions drive the activation of the QseB response regulator in the absence of its cognate sensor. Proc Natl Acad Sci U S A 2013; 110:16592-7. [PMID: 24062463 DOI: 10.1073/pnas.1315320110] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Bacterial two-component systems (TCSs) mediate specific responses to distinct conditions and/or stresses. TCS interactions are highly specific between cognate partners to avoid unintended cross-talk. Although cross-talk between a sensor kinase and a noncognate response regulator has been previously demonstrated, the majority of reported interactions have not been robust. Here, we report that in the case of the quorum-sensing Escherichia coli (Qse)BC TCS, absence of the cognate sensor QseC leads to robust, constitutive activation of the QseB response regulator by the noncognate polymyxin resistance (Pmr) sensor kinase PmrB. Remarkably, the noncognate PmrB exhibits a kinetic preference for QseB that is similar to QseC. However, although PmrB readily phosphorylates QseB in vitro, it is significantly less efficient at dephosphorylating QseB, compared with QseC, thereby explaining the increased levels of active QseB in the qseC mutant. In addition to PmrB activating QseB on the protein level, we found that the PmrA response regulator contributes to qseB transcription in the absence of QseC and PmrA specifically binds the qseBC promoter, indicative of a direct regulation of qseBC gene transcription by PmrAB under physiological conditions. Addition of ferric iron in the growth medium of wild-type uropathogenic E. coli induced the expression of qseBC in a PmrB-dependent manner. Taken together, our findings suggest that (i) robust cross-talk between noncognate partners is possible and (ii) this interaction can be manipulated for the development of antivirulence strategies aimed at targeting uropathogenic Escherichia coli and potentially other QseBC-PmrAB-bearing pathogens.
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Chen HD, Groisman EA. The biology of the PmrA/PmrB two-component system: the major regulator of lipopolysaccharide modifications. Annu Rev Microbiol 2013; 67:83-112. [PMID: 23799815 DOI: 10.1146/annurev-micro-092412-155751] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ability of gram-negative bacteria to resist killing by antimicrobial agents and to avoid detection by host immune systems often entails modification to the lipopolysaccharide (LPS) in their outer membrane. In this review, we examine the biology of the PmrA/PmrB two-component system, the major regulator of LPS modifications in the enteric pathogen Salmonella enterica. We examine the signals that activate the sensor PmrB and the targets controlled by the transcriptional regulator PmrA. We discuss the PmrA/PmrB-dependent chemical decorations of the LPS and their role in resistance to antibacterial agents. We analyze the feedback mechanisms that modulate the activity and thus output of the PmrA/PmrB system, dictating when, where, and to what extent bacteria modify their LPS. Finally, we explore the qualitative and quantitative differences in gene expression outputs resulting from the distinct PmrA/PmrB circuit architectures in closely related bacteria, which may account for their differential survival in various ecological niches.
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Nasri K, Daghfous D, Landoulsi A. Effects of microwave (2.45 GHz) irradiation on some biological characters of Salmonella typhimurium. C R Biol 2013; 336:194-202. [PMID: 23849722 DOI: 10.1016/j.crvi.2013.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
The present study was carried out to evaluate the effects of sub-lethal doses of microwave radiation on some biological characteristics in Salmonella typhimurium. The aim was to show the relationship between this treatment and the development of radiotolerance in this pathogen because there is a need for more information on physiological responses of pathogens to sub-lethal doses of microwave radiation. So, the bacterial strain was treated with a dose of 3600J (40-s exposure with power P=90 W) to cause cellular damage. The results have shown that the exposure of bacteria to microwaves resulted in a significant inhibition of cellular growth. This treatment has notably increased the effectiveness of the most tested antibiotics by the amelioration or the appearance of sensitivity in exposed bacteria. Gas chromatography (GC) analysis was performed to demonstrate the modification of the fatty acids (FA) composition. Results obtained have shown that this treatment had a significant effect on the FA content with an increase of unsaturated FA percentage. The acquisition of sensitivity to the sodium deoxycholate and the significant increase in the amount of extracellular proteins in exposed bacteria has confirmed the weakening of the bacterial membrane by microwaves. This study represents one of the few demonstrating the modifications on the bacterial membrane as a cellular response to survive the non-ionising radiation stress.
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Affiliation(s)
- Kaouther Nasri
- Laboratoire de biochimie et biologie moléculaire, faculté des sciences de Bizerte, 7021 Zarzouna, Tunisia.
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Beceiro A, Tomás M, Bou G. Antimicrobial resistance and virulence: a successful or deleterious association in the bacterial world? Clin Microbiol Rev 2013; 26:185-230. [PMID: 23554414 PMCID: PMC3623377 DOI: 10.1128/cmr.00059-12] [Citation(s) in RCA: 616] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria.
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Klein G, Müller-Loennies S, Lindner B, Kobylak N, Brade H, Raina S. Molecular and structural basis of inner core lipopolysaccharide alterations in Escherichia coli: incorporation of glucuronic acid and phosphoethanolamine in the heptose region. J Biol Chem 2013; 288:8111-8127. [PMID: 23372159 DOI: 10.1074/jbc.m112.445981] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It is well established that lipopolysaccharide (LPS) often carries nonstoichiometric substitutions in lipid A and in the inner core. In this work, the molecular basis of inner core alterations and their physiological significance are addressed. A new inner core modification of LPS is described, which arises due to the addition of glucuronic acid on the third heptose with a concomitant loss of phosphate on the second heptose. This was shown by chemical and structural analyses. Furthermore, the gene whose product is responsible for the addition of this sugar was identified in all Escherichia coli core types and in Salmonella and was designated waaH. Its deduced amino acid sequence exhibits homology to glycosyltransferase family 2. The transcription of the waaH gene is positively regulated by the PhoB/R two-component system in a growth phase-dependent manner, which is coordinated with the transcription of the ugd gene explaining the genetic basis of this modification. Glucuronic acid modification was observed in E. coli B, K12, R2, and R4 core types and in Salmonella. We also show that the phosphoethanolamine (P-EtN) addition on heptose I in E. coli K12 requires the product of the ORF yijP, a new gene designated as eptC. Incorporation of P-EtN is also positively regulated by PhoB/R, although it can occur at a basal level without a requirement for any regulatory inducible systems. This P-EtN modification is essential for resistance to a variety of factors, which destabilize the outer membrane like the addition of SDS or challenge to sublethal concentrations of Zn(2+).
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Affiliation(s)
- Gracjana Klein
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany; Department of Microbiology, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland
| | - Sven Müller-Loennies
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany
| | - Buko Lindner
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany
| | - Natalia Kobylak
- Department of Microbiology, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland
| | - Helmut Brade
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany
| | - Satish Raina
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, 23845 Borstel, Germany; Department of Microbiology, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.
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Cenens W, Makumi A, Mebrhatu MT, Lavigne R, Aertsen A. Phage-host interactions during pseudolysogeny: Lessons from the Pid/dgo interaction. BACTERIOPHAGE 2013; 3:e25029. [PMID: 23819109 PMCID: PMC3694060 DOI: 10.4161/bact.25029] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/06/2013] [Accepted: 05/13/2013] [Indexed: 12/11/2022]
Abstract
Although the study of phage infection has a long history and catalyzed much of our current understanding in bacterial genetics, molecular biology, evolution and ecology, it seems that microbiologists have only just begun to explore the intricacy of phage-host interactions. In a recent manuscript by Cenens et al. we found molecular and genetic support for pseudolysogenic development in the Salmonella Typhimurium-phage P22 model system. More specifically, we observed the existence of phage carrier cells harboring an episomal P22 element that segregated asymmetrically upon subsequent divisions. Moreover, a newly discovered P22 ORFan protein (Pid) able to derepress a metabolic operon of the host (dgo) proved to be specifically expressed in these phage carrier cells. In this addendum we expand on our view regarding pseudolysogeny and its effects on bacterial and phage biology.
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Affiliation(s)
- William Cenens
- Laboratory of Food Microbiology; Department of Microbial and Molecular Systems (M2S); Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium
| | - Angella Makumi
- Laboratory of Food Microbiology; Department of Microbial and Molecular Systems (M2S); Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium
| | - Mehari Tesfazgi Mebrhatu
- Laboratory of Food Microbiology; Department of Microbial and Molecular Systems (M2S); Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium
| | - Rob Lavigne
- Laboratory of Gene Technology; Department of Biosystems; Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology; Department of Microbial and Molecular Systems (M2S); Faculty of Bioscience Engineering; KU Leuven; Leuven, Belgium
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An altered immune response, but not individual cationic antimicrobial peptides, is associated with the oral attenuation of Ara4N-deficient Salmonella enterica serovar Typhimurium in mice. PLoS One 2012; 7:e49588. [PMID: 23166721 PMCID: PMC3499468 DOI: 10.1371/journal.pone.0049588] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/10/2012] [Indexed: 11/19/2022] Open
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) uses two-component regulatory systems (TCRS) to respond to stimuli in the local microenvironment. Upon infection, the Salmonella TCRSs PhoP-PhoQ (PhoPQ) and PmrA-PmrB (PmrAB) are activated by environmental signals in the intestinal lumen and within host cells. TCRS-mediated gene expression results in lipopolysaccharide (LPS) modification and cationic antimicrobial peptide resistance. The PmrA-regulated pmrHFIJKLM operon mediates 4-amino-4-deoxy-L-arabinose (Ara4N) production and attachment to the lipid A of LPS. A ΔpmrF S. Typhimurium strain cannot produce Ara4N, exhibits increased sensitivity to cationic antimicrobial peptide (CAMP)-mediated killing, and attenuated virulence in mice upon oral infection. CAMPs are predicted to play a role in elimination of Salmonella, and may activate PhoPQ and PmrAB in vivo, which could increase bacterial resistance to host defenses. Competition experiments between wild type (WT) and ΔpmrF mutant strains of S. Typhimurium indicated that selection against this mutant first occurs within the intestinal lumen early during infection. However, CRAMP and active cryptdins alone are not responsible for elimination of Ara4N-deficient bacteria in vivo. Investigation into the early immune response to ΔpmrF showed that it differed slightly from the early immune response to WT S. Typhimurium. Further investigation into the early immune response to infection of Peyer's patches suggests a role for IL-13 in the attenution of the ΔpmrF mutant strain. Thus, prominent CAMPs present in the mouse intestine are not responsible for the selection against the ΔpmrF strain in this location, but limited alterations in innate immune induction were observed that affect bacterial survival and virulence.
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Richards SM, Strandberg KL, Conroy M, Gunn JS. Cationic antimicrobial peptides serve as activation signals for the Salmonella Typhimurium PhoPQ and PmrAB regulons in vitro and in vivo. Front Cell Infect Microbiol 2012; 2:102. [PMID: 22919691 PMCID: PMC3417628 DOI: 10.3389/fcimb.2012.00102] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 07/06/2012] [Indexed: 02/06/2023] Open
Abstract
Salmonella enterica serovar Typhimurium uses two-component regulatory systems (TCRSs) to respond to environmental stimuli. Upon infection, the TCRSs PhoP-PhoQ (PhoPQ) and PmrA-PmrB (PmrAB) are activated by environmental signals detected in the lumen of the intestine and within host cells. TCRS-mediated gene expression leads to upregulation of genes involved in lipopolysaccharide (LPS) modification and cationic antimicrobial peptide (CAMP) resistance. This research expands on previous studies which have shown that CAMPs can activate Salmonella TCRSs in vitro. The focus of this work was to determine if CAMPs can act as environmental signals for PhoPQ- and PmrAB-mediated gene expression in vitro, during infection of macrophages and in a mouse model of infection. Monitoring of PhoPQ and PmrAB activation using recombinase-based in vivo expression technology (RIVET), alkaline phosphtase and β-galactosidase reporter fusion constructs demonstrated that S. Typhimurium PhoQ can sense CAMPs in vitro. In mouse macrophages, the cathelecidin CRAMP does not activate the PhoPQ regulon. Acidification of the Salmonella-containing vacuole activates PhoP- and PmrA-regulated loci but blocking acidification still does not reveal a role for CRAMP in TCRS activation in mouse macrophages. However, assays performed in susceptible wild type (WT), CRAMP knockout (KO), and matrilysin (a metalloproteinase necessary for activating murine α-defensins) KO mice suggest CRAMP, but not α-defensins, serve as a putative direct TCRS activation signal in the mouse intestine. These studies provide a better understanding of the in vivo environments that result in activation of these virulence-associated TCRSs.
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Affiliation(s)
- Susan M Richards
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus OH, USA
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Bile salts induce resistance to polymyxin in enterohemorrhagic Escherichia coli O157:H7. J Bacteriol 2011; 193:4509-15. [PMID: 21725004 DOI: 10.1128/jb.00200-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many enteric bacteria use bile as an environmental cue to signal resistance and virulence gene expression. Microarray analysis of enterohemorrhagic Escherichia coli O157:H7 (EHEC) treated with bile salts revealed upregulation of genes for an efflux system (acrAB), a two-component signal transduction system (basRS/pmrAB), and lipid A modification (arnBCADTEF and ugd). Bile salt treatment of EHEC produced a basS- and arnT-dependent resistance to polymyxin.
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Molecular characterization of the PhoPQ-PmrD-PmrAB mediated pathway regulating polymyxin B resistance in Klebsiella pneumoniae CG43. J Biomed Sci 2010; 17:60. [PMID: 20653976 PMCID: PMC2919465 DOI: 10.1186/1423-0127-17-60] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/24/2010] [Indexed: 11/16/2022] Open
Abstract
Background The cationic peptide antibiotic polymyxin has recently been reevaluated in the treatment of severe infections caused by gram negative bacteria. Methods In this study, the genetic determinants for capsular polysaccharide level and lipopolysaccharide modification involved in polymyxin B resistance of the opportunistic pathogen Klebsiella pneumoniae were characterized. The expressional control of the genes responsible for the resistance was assessed by a LacZ reporter system. The PmrD connector-mediated regulation for the expression of pmr genes involved in polymyxin B resistance was also demonstrated by DNA EMSA, two-hybrid analysis and in vitro phosphor-transfer assay. Results Deletion of the rcsB, which encoded an activator for the production of capsular polysaccharide, had a minor effect on K. pneumoniae resistance to polymyxin B. On the other hand, deletion of ugd or pmrF gene resulted in a drastic reduction of the resistance. The polymyxin B resistance was shown to be regulated by the two-component response regulators PhoP and PmrA at low magnesium and high iron, respectively. Similar to the control identified in Salmonella, expression of pmrD in K. pneumoniae was dependent on PhoP, the activated PmrD would then bind to PmrA to prolong the phosphorylation state of the PmrA, and eventually turn on the expression of pmr for the resistance to polymyxin B. Conclusions The study reports a role of the capsular polysaccharide level and the pmr genes for K. pneumoniae resistance to polymyxin B. The PmrD connector-mediated pathway in governing the regulation of pmr expression was demonstrated. In comparison to the pmr regulation in Salmonella, PhoP in K. pneumoniae plays a major regulatory role in polymyxin B resistance.
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The role of SurA factor in outer membrane protein transport and virulence. Int J Med Microbiol 2010; 300:421-8. [PMID: 20447864 DOI: 10.1016/j.ijmm.2010.04.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/16/2010] [Accepted: 04/05/2010] [Indexed: 11/22/2022] Open
Abstract
The Escherichia coli periplasmic chaperone and peptidyl-prolyl isomerase (PPIase) SurA is a major factor in the biogenesis of β-barrel outer membrane proteins (OMPs) and as such plays an integral role in cell envelope homeostasis and cell envelope functions. Recently, the biological importance of SurA was further substantiated by the finding that SurA also affects pathogenicity, being required for full virulence of uropathogenic Escherichia coli, Salmonella, and Shigella spp. Moreover, given the conservation of the protein, SurA likely plays similar roles in other Gram-negative bacteria and may hence prove a valuable drug target against Gram-negative pathogens. While our understanding on how SurA promotes transport and folding of β-barrel OMPs, how it provides support to virulence, and how it functions at a molecular level is still limited, major contributions have recently been made on our way to find answers to these questions. This review is a compilation of our current state of knowledge on E. coli SurA function and a discussion of recent findings with a particular emphasis on the pleiotropic contributions of SurA to pathogenicity.
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Periplasmic peptidyl-prolyl isomerases SurA and FkpA play an important role in the starvation-stress response (SSR) of Salmonella enterica serovar Typhimurium. Antonie van Leeuwenhoek 2010; 98:51-63. [PMID: 20232248 DOI: 10.1007/s10482-010-9428-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 03/04/2010] [Indexed: 10/19/2022]
Abstract
Carbon-energy source (C)-starved cells of Salmonella enterica serovar Typhimurium (S. Typhimurium) are remarkably more resistant to stress than actively growing ones. Carbon-starved S. Typhimurium is capable of withstanding extended periods of starvation and assault from a number of different stresses that rapidly kill growing cells. These unique properties of the C-starved cell are the direct result of a series of genetic and physiological adaptations referred to as the starvation-stress response (SSR). Previous work established that the SSR of S. Typhimurium is partially regulated by the extracytoplasmic function sigma factor sigma(E). As part of an effort to identify sigma(E)-regulated SSR genes, we investigated surA and fkpA, encoding two different classes of peptidyl-prolyl isomerase that function in folding cell envelope proteins. Both surA and fkpA are members of the heat-shock-inducible sigma(E) regulon of Escherichia coli. Although both genes are expressed in C-starved Salmonella cells, evidence indicates that surA and fkpA are not C-starvation-inducible. Furthermore, their expression during C-starvation does not appear to be sigma(E)-dependent. Nonetheless, surA and fkpA proved to be important, to differing degrees, for long-term C-starvation survival and for the cross-resistance of C-starved cells to high temperature, acidic pH, and the antimicrobial peptide polymyxin B, but neither were required for cross-resistance to oxidative stress. These results point to fundamental differences between heat-shock-inducible and C-starvation-inducible genes regulated by sigma(E) and suggest that genes other than surA and fkpA are involved in the sigma(E)-regulated branch of the SSR in Salmonella.
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Protecting against antimicrobial effectors in the phagosome allows SodCII to contribute to virulence in Salmonella enterica serovar Typhimurium. J Bacteriol 2010; 192:2140-9. [PMID: 20154132 DOI: 10.1128/jb.00016-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium replicates in macrophages, where it is subjected to antimicrobial substances, including superoxide, antimicrobial peptides, and proteases. The bacterium produces two periplasmic superoxide dismutases, SodCI and SodCII. Although both are expressed during infection, only SodCI contributes to virulence in the mouse by combating phagocytic superoxide. The differential contribution to virulence is at least partially due to inherent differences in the SodCI and SodCII proteins that are independent of enzymatic activity. SodCII is protease sensitive, and like other periplasmic proteins, it is released by osmotic shock. In contrast, SodCI is protease resistant and is retained within the periplasm after osmotic shock, a phenomenon that we term "tethering." We hypothesize that in the macrophage, antimicrobial peptides transiently disrupt the outer membrane. SodCII is released and/or phagocytic proteases gain access to the periplasm, and SodCII is degraded. SodCI is tethered within the periplasm and is protease resistant, thereby remaining to combat superoxide. Here we test aspects of this model. SodCII was released by the antimicrobial peptide polymyxin B or a mouse macrophage antimicrobial peptide (CRAMP), while SodCI remained tethered within the periplasm. A Salmonella pmrA constitutive mutant no longer released SodCII in vitro. Moreover, in the constitutive pmrA background, SodCII could contribute to survival of Salmonella during infection. SodCII also provided a virulence benefit in mice genetically defective in production of CRAMP. Thus, consistent with our model, protecting the outer membrane against antimicrobial peptides allows SodCII to contribute to virulence in vivo. These data also suggest direct in vivo cooperative interactions between macrophage antimicrobial effectors.
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Bonsor DA, Hecht O, Vankemmelbeke M, Sharma A, Krachler AM, Housden NG, Lilly KJ, James R, Moore GR, Kleanthous C. Allosteric beta-propeller signalling in TolB and its manipulation by translocating colicins. EMBO J 2009; 28:2846-57. [PMID: 19696740 PMCID: PMC2750012 DOI: 10.1038/emboj.2009.224] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 07/13/2009] [Indexed: 01/09/2023] Open
Abstract
The Tol system is a five-protein assembly parasitized by colicins and bacteriophages that helps stabilize the Gram-negative outer membrane (OM). We show that allosteric signalling through the six-bladed beta-propeller protein TolB is central to Tol function in Escherichia coli and that this is subverted by colicins such as ColE9 to initiate their OM translocation. Protein-protein interactions with the TolB beta-propeller govern two conformational states that are adopted by the distal N-terminal 12 residues of TolB that bind TolA in the inner membrane. ColE9 promotes disorder of this 'TolA box' and recruitment of TolA. In contrast to ColE9, binding of the OM lipoprotein Pal to the same site induces conformational changes that sequester the TolA box to the TolB surface in which it exhibits little or no TolA binding. Our data suggest that Pal is an OFF switch for the Tol assembly, whereas colicins promote an ON state even though mimicking Pal. Comparison of the TolB mechanism to that of vertebrate guanine nucleotide exchange factor RCC1 suggests that allosteric signalling may be more prevalent in beta-propeller proteins than currently realized.
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Affiliation(s)
| | - Oliver Hecht
- Centre for Molecular and Structural Biochemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK
| | - Mireille Vankemmelbeke
- School of Molecular Medical Sciences, Institute of Infection, Inflammation and Immunity, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Amit Sharma
- Department of Biology, University of York, York, UK
| | | | | | | | - Richard James
- School of Molecular Medical Sciences, Institute of Infection, Inflammation and Immunity, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - Geoffrey R Moore
- Centre for Molecular and Structural Biochemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK
| | - Colin Kleanthous
- Department of Biology, University of York, York, UK,Department of Biology (Area 10), University of York, Heslington, PO Box 373, York, YO10 5YW, UK. Tel.: +44 0 1904 328820; Fax: +44 0 1904 328825; E-mail:
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Cell envelope perturbation induces oxidative stress and changes in iron homeostasis in Vibrio cholerae. J Bacteriol 2009; 191:5398-408. [PMID: 19542276 DOI: 10.1128/jb.00092-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Vibrio cholerae type II secretion (T2S) machinery is a multiprotein complex that spans the cell envelope. When the T2S system is inactivated, cholera toxin and other exoproteins accumulate in the periplasmic compartment. Additionally, loss of secretion via the T2S system leads to a reduced growth rate, compromised outer membrane integrity, and induction of the extracytoplasmic stress factor RpoE (A. E. Sikora, S. R. Lybarger, and M. Sandkvist, J. Bacteriol. 189:8484-8495, 2007). In this study, gene expression profiling reveals that inactivation of the T2S system alters the expression of genes encoding cell envelope components and proteins involved in central metabolism, chemotaxis, motility, oxidative stress, and iron storage and acquisition. Consistent with the gene expression data, molecular and biochemical analyses indicate that the T2S mutants suffer from internal oxidative stress and increased levels of intracellular ferrous iron. By using a tolA mutant of V. cholerae that shares a similar compromised membrane phenotype but maintains a functional T2S machinery, we show that the formation of radical oxygen species, induction of oxidative stress, and changes in iron physiology are likely general responses to cell envelope damage and are not unique to T2S mutants. Finally, we demonstrate that disruption of the V. cholerae cell envelope by chemical treatment with polymyxin B similarly results in induction of the RpoE-mediated stress response, increased sensitivity to oxidants, and a change in iron metabolism. We propose that many types of extracytoplasmic stresses, caused either by genetic alterations of outer membrane constituents or by chemical or physical damage to the cell envelope, induce common signaling pathways that ultimately lead to internal oxidative stress and misregulation of iron homeostasis.
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50
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Lai S, Tremblay J, Déziel E. Swarming motility: a multicellular behaviour conferring antimicrobial resistance. Environ Microbiol 2009; 11:126-36. [DOI: 10.1111/j.1462-2920.2008.01747.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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