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Kago G, Turnbough CL, Salazar JC, Payne SM. (p)ppGpp is required for virulence of Shigella flexneri. Infect Immun 2024; 92:e0033423. [PMID: 38099658 PMCID: PMC10790822 DOI: 10.1128/iai.00334-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 11/16/2023] [Indexed: 01/17/2024] Open
Abstract
Infection by the enteric pathogen Shigella flexneri requires transit through the gastrointestinal tract and invasion of and replication within the cells of the host colonic epithelium. This process exposes the pathogen to a range of diverse microenvironments. Furthermore, the unique composition and physical environment of the eukaryotic cell cytosol represents a stressful environment for S. flexneri, and extensive physiological adaptations are needed for the bacterium to thrive. In this work, we show that disrupting synthesis of the stringent response alarmone (p)ppGpp in S. flexneri diminished expression of key virulence genes, including ipaA, ipaB, ipaC, and icsA, and it reduced bacterial invasion and intercellular spread. Deletion of the (p)ppGpp synthase gene relA alone had no effect on S. flexneri virulence, but disruption of both relA and the (p)ppGpp synthase/hydrolase gene spoT resulted in loss of (p)ppGpp synthesis and virulence. While the relA spoT deletion mutant was able to invade a cultured human epithelial cell monolayer, albeit at reduced levels, it was unable to maintain the infection and spread to adjacent cells, as indicated by loss of plaque formation. Complementation with spoT on a plasmid vector restored plaque formation. Thus, SpoT alone is sufficient to provide the necessary level of (p)ppGpp for virulence. These results indicate that (p)ppGpp is required for S. flexneri virulence and adaptation to the intracellular environment, adding to the repertoire of signaling pathways that affect Shigella pathogenesis.
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Affiliation(s)
- Grace Kago
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Charles L. Turnbough
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Shelley M. Payne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
- John Ring LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, Texas, USA
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2
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Sinha R, LeVeque RM, Callahan SM, Chatterjee S, Stopnisek N, Kuipel M, Johnson JG, DiRita VJ. Gut metabolite L-lactate supports Campylobacter jejuni population expansion during acute infection. Proc Natl Acad Sci U S A 2024; 121:e2316540120. [PMID: 38170751 PMCID: PMC10786315 DOI: 10.1073/pnas.2316540120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/15/2023] [Indexed: 01/05/2024] Open
Abstract
How the microaerobic pathogen Campylobacter jejuni establishes its niche and expands in the gut lumen during infection is poorly understood. Using 6-wk-old ferrets as a natural disease model, we examined this aspect of C. jejuni pathogenicity. Unlike mice, which require significant genetic or physiological manipulation to become colonized with C. jejuni, ferrets are readily infected without the need to disarm the immune system or alter the gut microbiota. Disease after C. jejuni infection in ferrets reflects closely how human C. jejuni infection proceeds. Rapid growth of C. jejuni and associated intestinal inflammation was observed within 2 to 3 d of infection. We observed pathophysiological changes that were noted by cryptic hyperplasia through the induction of tissue repair systems, accumulation of undifferentiated amplifying cells on the colon surface, and instability of HIF-1α in colonocytes, which indicated increased epithelial oxygenation. Metabolomic analysis demonstrated that lactate levels in colon content were elevated in infected animals. A C. jejuni mutant lacking lctP, which encodes an L-lactate transporter, was significantly decreased for colonization during infection. Lactate also influences adhesion and invasion by C. jejuni to a colon carcinoma cell line (HCT116). The oxygenation required for expression of lactate transporter (lctP) led to identification of a putative thiol-based redox switch regulator (LctR) that may repress lctP transcription under anaerobic conditions. Our work provides better insights into the pathogenicity of C. jejuni.
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Affiliation(s)
- Ritam Sinha
- Department of Microbiology, Genetics, & Immunology, Michigan State University, East Lansing, MI48824
| | - Rhiannon M. LeVeque
- Department of Microbiology, Genetics, & Immunology, Michigan State University, East Lansing, MI48824
| | - Sean M. Callahan
- Department of Microbiology, University of Tennessee, Knoxville, TN37996
| | - Shramana Chatterjee
- Department of Microbiology, Genetics, & Immunology, Michigan State University, East Lansing, MI48824
| | - Nejc Stopnisek
- Department of Microbiology, Genetics, & Immunology, Michigan State University, East Lansing, MI48824
| | - Matti Kuipel
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI48824
| | | | - Victor J. DiRita
- Department of Microbiology, Genetics, & Immunology, Michigan State University, East Lansing, MI48824
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3
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Sinha R, LeVeque RM, Callahan SM, Chatterjee S, Stopnisek N, Kuipel M, Johnson JG, DiRita VJ. Gut metabolite L-lactate supports Campylobacter jejuni population expansion during acute infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560557. [PMID: 37873437 PMCID: PMC10592923 DOI: 10.1101/2023.10.02.560557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
How the microaerobic pathogen Campylobacter jejuni establishes its niche and expands in the gut lumen during infection is poorly understood. Using six-week-old ferrets as a natural disease model, we examined this aspect of C. jejuni pathogenicity. Unlike mice, which require significant genetic or physiological manipulation to become colonized with C. jejuni , ferrets are readily infected without the need to disarm the immune system or alter the gut microbiota. Disease after C. jejuni infection in ferrets reflects closely how human C. jejuni infection proceeds. Rapid growth of C. jejuni and associated intestinal inflammation was observed within two-three days of infection. We observed pathophysiological changes that were noted by cryptic hyperplasia through the induction of tissue repair systems, accumulation of undifferentiated amplifying cells on the colon surface, and instability of HIF-1α in colonocytes, which indicated increased epithelial oxygenation. Metabolomic analysis demonstrated that lactate levels in colon content were elevated in infected animals. A C. jejuni mutant lacking lctP , which encodes an L-lactate transporter, was significantly decreased for colonization during infection. Lactate also influences adhesion and invasion by C. jejuni to a colon carcinoma cell line (HCT116). The oxygenation required for expression of lactate transporter ( lctP ) led to discovery of a putative thiol based redox switch regulator (LctR) that may repress lctP transcription under anaerobic conditions. Our work provides new insights into the pathogenicity of C. jejuni . Significance There is a gap in knowledge about the mechanisms by which C. jejuni populations expand during infection. Using an animal model which accurately reflects human infection without the need to alter the host microbiome or the immune system prior to infection, we explored pathophysiological alterations of the gut after C. jejuni infection. Our study identified the gut metabolite L-lactate as playing an important role as a growth substrate for C. jejuni during acute infection. We identified a DNA binding protein, LctR, that binds to the lctP promoter and may repress lctP expression, resulting in decreased lactate transport under low oxygen levels. This work provides new insights about C. jejuni pathogenicity.
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An Experimental Adult Zebrafish Model for Shigella Pathogenesis, Transmission, and Vaccine Efficacy Studies. Microbiol Spectr 2022; 10:e0034722. [PMID: 35604149 PMCID: PMC9241715 DOI: 10.1128/spectrum.00347-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shigellosis has been a menace to society for ages. The absence of an effective vaccine against Shigella, improper sanitation, and unhygienic use of food and water allow the disease to flourish. Shigella can also be transmitted via natural water bodies. In the absence of a good animal model, the actual nature of pathogenesis and transmission remains unclear. Zebrafish larvae have previously been described as a model for Shigella pathogenesis. However, larval fish lack a mature intestinal microbiota and immune system. Here, the adult zebrafish was assessed as a potential model for Shigella pathogenesis. Their well-developed innate and adaptive immune responses mimic the mammalian immune system. Shigella showed a clear dose-, time-, and temperature-dependent colonization of the adult zebrafish gut. Efficacy of a three-dose immunization regime was tested using bath immunization with heat-killed trivalent Shigella immunogen. The present study demonstrates the efficacy of an adult zebrafish model for pathogenesis, transmission, and vaccine efficacy studies. IMPORTANCE Shigellosis is a diarrheal disease that is prevalent in developing countries and especially dangerous in young children. Currently, animal models for shigellosis are unable to model some aspects of the infectious cycle. Here, we describe a new shigellosis model in adult zebrafish, an increasingly common model organism for studying bacterial pathogens. The zebrafish model can be used to study Shigella colonization, transmission, and immune responses, as well as test vaccine efficacy.
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Yang Y, Hu P, Gao L, Yuan X, Hardwidge PR, Li T, Li P, He F, Peng Y, Li N. Deleting qseC downregulates virulence and promotes cross-protection in Pasteurella multocida. Vet Res 2021; 52:140. [PMID: 34801081 PMCID: PMC8605557 DOI: 10.1186/s13567-021-01009-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/18/2021] [Indexed: 11/25/2022] Open
Abstract
QseC, a histidine sensor kinase of the QseBC two-component system, acts as a global regulator of bacterial stress resistance, biofilm formation, and virulence. The function of QseC in some bacteria is well understood, but not in Pasteurella multocida. We found that deleting qseC in P. multocida serotype A:L3 significantly down-regulated bacterial virulence. The mutant had significantly reduced capsule production but increased resistance to oxidative stress and osmotic pressure. Deleting qseC led to a significant increase in qseB expression. Transcriptome sequencing analysis showed that 1245 genes were regulated by qseC, primarily those genes involved in capsule and LPS biosynthesis and export, biofilm formation, and iron uptake/utilization, as well as several immuno-protection related genes including ompA, ptfA, plpB, vacJ, and sodA. In addition to presenting strong immune protection against P. multocida serotypes A:L1 and A:L3 infection, live ΔqseC also exhibited protection against P. multocida serotype B:L2 and serotype F:L3 infection in a mouse model. The results indicate that QseC regulates capsular production and virulence in P. multocida. Furthermore, the qseC mutant can be used as an attenuated vaccine against P. multocida strains of multiple serotypes.
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Affiliation(s)
- Yang Yang
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Pei Hu
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Lixu Gao
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Xiang Yuan
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Tian Li
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Pan Li
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Fang He
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China
| | - Yuanyi Peng
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China.
| | - Nengzhang Li
- College of Veterinary Medicine, Southwest University, Chongqing, 400716, China.
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6
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Tilahun M, Kassa Y, Gedefie A, Ashagire M. Emerging Carbapenem-Resistant Enterobacteriaceae Infection, Its Epidemiology and Novel Treatment Options: A Review. Infect Drug Resist 2021; 14:4363-4374. [PMID: 34707380 PMCID: PMC8544126 DOI: 10.2147/idr.s337611] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/13/2021] [Indexed: 12/15/2022] Open
Abstract
Infections due to multidrug-resistant Enterobacteriaceae have become major international public health problem due to the inadequate treatment options and the historically lagged pace of development of novel antimicrobial drugs. Inappropriate antimicrobial use in humans and animals coupled with increased global connectivity aided to the transmission of drug-resistant Enterobacteriaceae infections. Carbapenems are the medications of choice for extended-spectrum beta-lactamase and AmpC producers, but alternatives are currently needed because carbapenem resistance is increasing globally. This review pointed to discuss emerging drug-resistant Enterobacteriaceae, its epidemiology and novel treatment options for infections, which date back from 2010 to 2019 by searching Google Scholar, PubMed, PMC, Hinari and other different websites. The occurrence of carbapenem-resistant Enterobacteriaceae is reported worldwide with great regional variability. The rise of carbapenem-resistant Enterobacteriaceae poses a threat to all nations. Enzyme synthesis, efflux pumps, and porin mutations are the main methods by which Enterobacteriaceae acquire resistance to carbapenems. The major resistance mechanism among these is enzyme synthesis. Most carbapenem resistance is caused by three enzyme groups: Klebsiella pneumoniae carbapenemase (Ambler class A), metallo-ß-lactamases (Ambler class B), and oxacillinase-48 (Ambler class D). Ceftazidime–avibactam, which was newly licensed for carbapenemase producers, is the most common treatment option for infections. Meropenem–vaborbactam, imipenem–relebactam, plazomicin, cefiderocol, eravacycline, and aztreonam–avibactam are recently reported to be active against carbapenem-resistant Enterobacteriaceae; and are also in ongoing trials for different populations and combinations with other antibacterial agents. Overall, treatment must be tailored to the patient’s susceptibility profile, type and degree of infection, and personal characteristics.
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Affiliation(s)
- Mihret Tilahun
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Yeshimebet Kassa
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Alemu Gedefie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
| | - Melaku Ashagire
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Wollo University, Dessie, Ethiopia
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Recent Progress in Shigella and Burkholderia pseudomallei Vaccines. Pathogens 2021; 10:pathogens10111353. [PMID: 34832508 PMCID: PMC8621228 DOI: 10.3390/pathogens10111353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/28/2022] Open
Abstract
Significant advancement has been made in the development of vaccines against bacterial pathogens. However, several roadblocks have been found during the evaluation of vaccines against intracellular bacterial pathogens. Therefore, new lessons could be learned from different vaccines developed against unrelated intracellular pathogens. Bacillary dysentery and melioidosis are important causes of morbidity and mortality in developing nations, which are caused by the intracellular bacteria Shigella and Burkholderia pseudomallei, respectively. Although the mechanisms of bacterial infection, dissemination, and route of infection do not provide clues about the commonalities of the pathogenic infectious processes of these bacteria, a wide variety of vaccine platforms recently evaluated suggest that in addition to the stimulation of antibodies, identifying protective antigens and inducing T cell responses are some additional required elements to induce effective protection. In this review, we perform a comparative evaluation of recent candidate vaccines used to combat these two infectious agents, emphasizing the common strategies that can help investigators advance effective and protective vaccines to clinical trials.
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García A, Fox JG. A One Health Perspective for Defining and Deciphering Escherichia coli Pathogenic Potential in Multiple Hosts. Comp Med 2021; 71:3-45. [PMID: 33419487 PMCID: PMC7898170 DOI: 10.30802/aalas-cm-20-000054] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/17/2020] [Accepted: 09/19/2020] [Indexed: 11/05/2022]
Abstract
E. coli is one of the most common species of bacteria colonizing humans and animals. The singularity of E. coli 's genus and species underestimates its multifaceted nature, which is represented by different strains, each with different combinations of distinct virulence factors. In fact, several E. coli pathotypes, or hybrid strains, may be associated with both subclinical infection and a range of clinical conditions, including enteric, urinary, and systemic infections. E. coli may also express DNA-damaging toxins that could impact cancer development. This review summarizes the different E. coli pathotypes in the context of their history, hosts, clinical signs, epidemiology, and control. The pathotypic characterization of E. coli in the context of disease in different animals, including humans, provides comparative and One Health perspectives that will guide future clinical and research investigations of E. coli infections.
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Key Words
- aa, aggregative adherence
- a/e, attaching and effacing
- aepec, atypical epec
- afa, afimbrial adhesin
- aida-i, adhesin involved in diffuse adherence
- aiec, adherent invasive e. coli
- apec, avian pathogenic e. coli
- atcc, american type culture collection
- bfp, bundle-forming pilus
- cd, crohn disease
- cdt, cytolethal distending toxin gene
- clb, colibactin
- cnf, cytotoxic necrotizing factor
- cs, coli surface (antigens)
- daec, diffusely adhering e. coli
- db, dutch belted
- eae, e. coli attaching and effacing gene
- eaec, enteroaggregative e. coli
- eaf, epec adherence factor (plasmid)
- eahec, entero-aggregative-hemorrhagic e. coli
- east-1, enteroaggregative e. coli heat-stable enterotoxin
- e. coli, escherichia coli
- ed, edema disease
- ehec, enterohemorrhagic e. coli
- eiec, enteroinvasive e. coli
- epec, enteropathogenic e. coli
- esbl, extended-spectrum β-lactamase
- esp, e. coli secreted protein
- etec, enterotoxigenic e. coli
- expec, extraintestinal pathogenic e. coli
- fyua, yersiniabactin receptor gene
- gi, gastrointestinal
- hly, hemolysin
- hus, hemolytic uremic syndrome
- ibd, inflammatory bowel disease
- la, localized adherence
- lee, locus of enterocyte effacement
- lpf, long polar fimbriae
- lt, heat-labile (enterotoxin)
- mlst, multilocus sequence typing
- ndm, new delhi metallo-β-lactamase
- nzw, new zealand white
- pap, pyelonephritis-associated pilus
- pks, polyketide synthase
- sfa, s fimbrial adhesin
- slt, shiga-like toxin
- st, heat-stable (enterotoxin)
- stec, stx-producing e. coli
- stx, shiga toxin
- tepec, typical epec
- upec, uropathogenic e. coli
- uti, urinary tract infection
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Affiliation(s)
- Alexis García
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, Puerto Rico; Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts; Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts;,
| | - James G Fox
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts
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Superstructure formation by RodZ hexamers of Shigella sonnei maintains the rod shape of bacilli. PLoS One 2020; 15:e0228052. [PMID: 32053625 PMCID: PMC7018016 DOI: 10.1371/journal.pone.0228052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/06/2020] [Indexed: 11/19/2022] Open
Abstract
The rod shape of bacilli is maintained by bacterial cytoskeletal protein MreB, an actin homolog that acts in concert with the inner membrane protein RodZ. We previously reported RodZ binds RNA to control the posttranscriptional regulation of invE (virB), which controls the type III secretion system essential for the virulence of Shigella. Here, we show that purified RodZ forms "superstructures" of high molecular mass that dissociate into a midsized "basal complex" in the presence of nonionic detergent, or to a monomer in the presence of dithiothreitol. We used mass spectrometry to show that the basal complex was a hexamer. Electrophoresis mobility shift assays combined with gel filtration detected the RNA-binding activity in fractions containing molecules larger than the basal hexamer. The superstructure was consistently detected with MreB in crude cell lysates of S. sonnei that were fractionated using gel filtration. Immunofluorescence microscopy using two different super-resolution settings showed that wild-type RodZ was distributed in cells as separate dots. Consistent with the superstructure comprising homohexamers, majority of the dots distributed among areas of discrete values. In addition, simultaneous immunodetection of MreB provided the first evidence of colocalization with RodZ as larger patch like signals. These findings indicate that native RodZ forms clusters of various sizes, which may correspond to a superstructure comprising multiple hexamers required for the RNA-binding activity.
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Gestal MC, Howard LK, Dewan K, Johnson HM, Barbier M, Bryant C, Soumana IH, Rivera I, Linz B, Blas-Machado U, Harvill ET. Enhancement of immune response against Bordetella spp. by disrupting immunomodulation. Sci Rep 2019; 9:20261. [PMID: 31889098 PMCID: PMC6937331 DOI: 10.1038/s41598-019-56652-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/12/2019] [Indexed: 12/27/2022] Open
Abstract
Well-adapted pathogens must evade clearance by the host immune system and the study of how they do this has revealed myriad complex strategies and mechanisms. Classical bordetellae are very closely related subspecies that are known to modulate adaptive immunity in a variety of ways, permitting them to either persist for life or repeatedly infect the same host. Exploring the hypothesis that exposure to immune cells would cause bordetellae to induce expression of important immunomodulatory mechanisms, we identified a putative regulator of an immunomodulatory pathway. The deletion of btrS in B. bronchiseptica did not affect colonization or initial growth in the respiratory tract of mice, its natural host, but did increase activation of the inflammasome pathway, and recruitment of inflammatory cells. The mutant lacking btrS recruited many more B and T cells into the lungs, where they rapidly formed highly organized and distinctive Bronchial Associated Lymphoid Tissue (BALT) not induced by any wild type Bordetella species, and a much more rapid and strong antibody response than observed with any of these species. Immunity induced by the mutant was measurably more robust in all respiratory organs, providing completely sterilizing immunity that protected against challenge infections for many months. Moreover, the mutant induced sterilizing immunity against infection with other classical bordetellae, including B. pertussis and B. parapertussis, something the current vaccines do not provide. These findings reveal profound immunomodulation by bordetellae and demonstrate that by disrupting it much more robust protective immunity can be generated, providing a pathway to greatly improve vaccines and preventive treatments against these important pathogens.
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Affiliation(s)
- Monica C Gestal
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
| | - Laura K Howard
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Kalyan Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Hannah M Johnson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, WV, United States of America
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, United States of America
| | - Clare Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Illiassou Hamidou Soumana
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Uriel Blas-Machado
- Department of Pathology, Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, Georgia, United States of America
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
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Ranjbar R, Farahani A. Shigella: Antibiotic-Resistance Mechanisms And New Horizons For Treatment. Infect Drug Resist 2019; 12:3137-3167. [PMID: 31632102 PMCID: PMC6789722 DOI: 10.2147/idr.s219755] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/28/2019] [Indexed: 12/17/2022] Open
Abstract
Shigella spp. are a common cause of diarrheal disease and have remained an important pathogen responsible for increased rates of morbidity and mortality caused by dysentery each year around the globe. Antibiotic treatment of Shigella infections plays an essential role in reducing prevalence and death rates of the disease. However, treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. Drug resistance in Shigella spp. can result from many mechanisms, such as decrease in cellular permeability, extrusion of drugs by active efflux pumps, and overexpression of drug-modifying and -inactivating enzymes or target modification by mutation. Therefore, there is an increasing need for identification and evolution of alternative therapeutic strategies presenting innovative avenues against Shigella infections, as well as paying further attention to this infection. The current review focuses on various antibiotic-resistance mechanisms of Shigella spp. with a particular emphasis on epidemiology and new mechanisms of resistance and their acquisition, and also discusses the status of novel strategies for treatment of Shigella infection and vaccine candidates currently under evaluation in preclinical or clinical phases.
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Affiliation(s)
- Reza Ranjbar
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Abbas Farahani
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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12
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Noster J, Chao TC, Sander N, Schulte M, Reuter T, Hansmeier N, Hensel M. Proteomics of intracellular Salmonella enterica reveals roles of Salmonella pathogenicity island 2 in metabolism and antioxidant defense. PLoS Pathog 2019; 15:e1007741. [PMID: 31009521 PMCID: PMC6497321 DOI: 10.1371/journal.ppat.1007741] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 05/02/2019] [Accepted: 03/28/2019] [Indexed: 11/18/2022] Open
Abstract
Intracellular Salmonella enterica serovar Typhimurium (STM) deploy the Salmonella Pathogenicity Island 2-encoded type III secretion system (SPI2-T3SS) for the massive remodeling of the endosomal system for host cells. This activity results in formation of an extensive interconnected tubular network of Salmonella-induced filaments (SIFs) connected to the Salmonella-containing vacuole (SCV). Such network is absent in cells infected with SPI2-T3SS-deficient mutant strains such as ΔssaV. A tubular network with reduced dimensions is formed if SPI2-T3SS effector protein SseF is absent. Previous single cell live microscopy-based analyses revealed that intracellular proliferation of STM is directly correlated to the ability to transform the host cell endosomal system into a complex tubular network. This network may also abrogate host defense mechanisms such as delivery of antimicrobial effectors to the SCV. To test the role of SIFs in STM patho-metabolism, we performed quantitative comparative proteomics of STM recovered from infected murine macrophages. We infected RAW264.7 cells with STM wild type (WT), ΔsseF or ΔssaV strains, recovered bacteria 12 h after infection and determined proteome compositions. Increased numbers of proteins characteristic for nutritional starvation were detected in STM ΔsseF and ΔssaV compared to WT. In addition, STM ΔssaV, but not ΔsseF showed signatures of increased exposure to stress by antimicrobial defenses, in particular reactive oxygen species, of the host cells. The proteomics analyses presented here support and extend the role of SIFs for the intracellular lifestyle of STM. We conclude that efficient manipulation of the host cell endosomal system by effector proteins of the SPI2-T3SS contributes to nutrition, as well as to resistance against antimicrobial host defense mechanisms. The facultative intracellular bacterium Salmonella enterica has evolved sophisticated mechanisms to adapt to life inside a pathogen-containing vacuole in mammalian host cells. Intracellular Salmonella manipulate the host cell endosomal system resulting in formation of a complex network of tubular vesicles, termed Salmonella-induced filaments (SIFs). We applied quantitative proteomics to intracellular Salmonella in murine macrophages and compared the wild-type strain to mutant strains with aberrant SIF architecture, or no capacity for induction of SIF. We determined that those mutant strains contain higher amounts of transporters for nutrient uptake, and lower amounts of proteins for central carbon metabolism. These observations indicate response to nutrient restriction in absence of fully established SIF. In addition, the mutant strain unable to induce SIF formation showed increased amounts of proteins required for response to antimicrobial factors of the host cells. These data show that the massive remodeling of the endosomal system of host cells by intracellular Salmonella serves to essential needs, i.e. to enable access to nutrients for efficient proliferation of the pathogen, and to withstand hostile conditions within the pathogen-containing vacuole.
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Affiliation(s)
- Janina Noster
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Tzu-Chiao Chao
- Institute of Environmental Change & Society, University of Regina, Regina, Canada
| | - Nathalie Sander
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Marc Schulte
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Tatjana Reuter
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Nicole Hansmeier
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.,Institute of Environmental Change & Society, University of Regina, Regina, Canada
| | - Michael Hensel
- Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
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Assembly, Biochemical Characterization, Immunogenicity, Adjuvanticity, and Efficacy of Shigella Artificial Invaplex. mSphere 2018; 3:mSphere00583-17. [PMID: 29600284 PMCID: PMC5874444 DOI: 10.1128/msphere.00583-17] [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: 12/11/2017] [Accepted: 02/02/2018] [Indexed: 11/20/2022] Open
Abstract
The native Invaplex (InvaplexNAT) vaccine and adjuvant is an ion exchange-purified product derived from the water extract of virulent Shigella species. The key component of InvaplexNAT is a high-molecular-mass complex (HMMC) consisting of the Shigella lipopolysaccharide (LPS) and the invasin proteins IpaB and IpaC. To improve product purity and immunogenicity, artificial Invaplex (InvaplexAR) was developed using recombinant IpaB and IpaC proteins and purified Shigella LPS to assemble an HMMC consisting of all three components. Characterization of InvaplexAR by various methods demonstrated similar characteristics as the previously reported HMMC in InvaplexNAT. The well-defined InvaplexAR vaccine consistently contained greater quantities of IpaB, IpaC, and LPS than InvaplexNAT. InvaplexAR and InvaplexNAT immunogenicities were compared in mouse and guinea pig dose escalation studies. In both models, immunization induced antibody responses specific for InvaplexNAT and LPS while InvaplexAR induced markedly higher anti-IpaB and -IpaC serum IgG and IgA endpoint titers. In the murine model, homologous protection was achieved with 10-fold less InvaplexAR than InvaplexNAT and mice receiving InvaplexAR lost significantly less weight than mice receiving the same amount of InvaplexNAT. Moreover, mice immunized with InvaplexAR were protected from challenge with both homologous and heterologous Shigella serotypes. Guinea pigs receiving approximately 5-fold less InvaplexAR compared to cohorts immunized with InvaplexNAT were protected from ocular challenge. Furthermore, adjuvanticity previously attributed to InvaplexNAT was retained with InvaplexAR. The second-generation Shigella Invaplex vaccine, InvaplexAR, offers significant advantages over InvaplexNAT in reproducibility, flexible yet defined composition, immunogenicity, and protective efficacy. IMPORTANCEShigella species are bacteria that cause severe diarrheal disease worldwide, primarily in young children. Treatment of shigellosis includes oral fluids and antibiotics, but the high burden of disease, increasing prevalence of antibiotic resistance, and long-term health consequences clearly warrant the development of an effective vaccine. One Shigella vaccine under development is termed the invasin complex or Invaplex and is designed to drive an immune response to specific antigens of the bacteria in an effort to protect an individual from infection. The work presented here describes the production and evaluation of a new generation of Invaplex. The improved vaccine stimulates the production of antibodies in immunized mice and guinea pigs and protects these animals from Shigella infection. The next step in the product's development will be to test the safety and immune response induced in humans immunized with Invaplex.
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