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Zhu Q, Lin Q, Jiang Y, Chen S, Tian J, Yang S, Li Y, Li M, Wang Y, Shen C, Meng S, Yang L, Feng Y, Qu J. Construction and application of the conditionally essential gene knockdown library in Klebsiella pneumoniae to screen potential antimicrobial targets and virulence genes via Mobile-CRISPRi-seq. Appl Environ Microbiol 2023; 89:e0095623. [PMID: 37815340 PMCID: PMC10617577 DOI: 10.1128/aem.00956-23] [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: 06/05/2023] [Accepted: 08/09/2023] [Indexed: 10/11/2023] Open
Abstract
Klebsiella pneumoniae is a ubiquitous human pathogen, and its clinical treatment faces two major challenges: multidrug resistance and the pathogenesis of hypervirulent K. pneumoniae. The discovery and study of conditionally essential (CE) genes that can function as potential antimicrobial targets has always been a research concern due to their restriction in the development of novel antibiotics. However, the lack of essential functional genomic data has hampered the study of the mechanisms of essential genes related to antimicrobial susceptibility. In this study, we developed a pooled CE genes mobile clustered regularly interspaced short palindromic repeat (CRISPR) interference screening method (Mobile-CRISPRi-seq) for K. pneumoniae to identify genes that play critical roles in antimicrobial fitness in vitro and host immunity in vivo. Targeting 870 predicted CE genes in K. pneumoniae, Mobile-CRISPRi-seq uncovered the depletion of tetrahydrofolate synthesis pathway genes folB and folP under trimethoprim pressure. Our screening also identified genes waaE and fldA related to polymyxin and β-lactam susceptibility by applying a screening strategy based on Mobile-CRISPRi-seq and comparative genomics. Furthermore, using a mouse infection model and Mobile-CRISPRi-seq, multiple virulence genes were identified, and among these genes, pal, yciS, and ribB were demonstrated to contribute to the pathogenesis of K. pneumoniae. This study provides a simple, rapid, and effective platform for screening potential antimicrobial targets and virulence genes in K. pneumoniae, and this broadly applicable system can be expanded for high-throughput functional gene study in multiple pathogenic bacteria, especially in gram-negative bacteria. IMPORTANCE The discovery and investigation of conditionally essential (CE) genes that can function as potential antimicrobial targets has always been a research concern because of the restriction of antimicrobial targets in the development of novel antibiotics. In this study, we developed a pooled CE gene-wide mobile clustered regularly interspaced short palindromic repeat (CRISPR) interference sequencing (Mobile-CRISPRi-seq) strategy in Klebsiella pneumoniae to identify genes that play critical roles in the fitness of antimicrobials in vitro and host immunity in vivo. The data suggest a robust tool to screen for loss-of-function phenotypes in a pooled gene knockdown library in K. pneumoniae, and Mobile-CRISPRi-seq may be expanded to multiple bacteria for screening and identification of genes with crucial roles in the fitness of antimicrobials and hosts.
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Affiliation(s)
- Qing Zhu
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Qiang Lin
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong Province, China
| | - Yushan Jiang
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Shuyan Chen
- Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Junxuan Tian
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Shijin Yang
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Yuanchun Li
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Mengjun Li
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Yuelin Wang
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Chenguang Shen
- BSL-3 Laboratory (Guangdong), Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Songdong Meng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences (CAS), Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Liang Yang
- Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Key University Laboratory of Metabolism and Health of Guangdong, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Youjun Feng
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Jiuxin Qu
- Department of Clinical Laboratory, Shenzhen Third People’s Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong Province, China
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da Silva GC, Rossi CC, Rosa JN, Sanches NM, Cardoso DL, Li Y, Witney AA, Gould KA, Fontes PP, Callaghan AJ, Bossé JT, Langford PR, Bazzolli DMS. Identification of small RNAs associated with RNA chaperone Hfq reveals a new stress response regulator in Actinobacillus pleuropneumoniae. Front Microbiol 2022; 13:1017278. [PMID: 36267174 PMCID: PMC9577009 DOI: 10.3389/fmicb.2022.1017278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022] Open
Abstract
The RNA chaperone Hfq promotes the association of small RNAs (sRNAs) with cognate mRNAs, controlling the expression of bacterial phenotype. Actinobacillus pleuropneumoniae hfq mutants strains are attenuated for virulence in pigs, impaired in the ability to form biofilms, and more susceptible to stress, but knowledge of the extent of sRNA involvement is limited. Here, using A. pleuropneumoniae strain MIDG2331 (serovar 8), 14 sRNAs were identified by co-immunoprecipitation with Hfq and the expression of eight, identified as trans-acting sRNAs, were confirmed by Northern blotting. We focused on one of these sRNAs, named Rna01, containing a putative promoter for RpoE (stress regulon) recognition. Knockout mutants of rna01 and a double knockout mutant of rna01 and hfq, both had decreased biofilm formation and hemolytic activity, attenuation for virulence in Galleria mellonella, altered stress susceptibility, and an altered outer membrane protein profile. Rna01 affected extracellular vesicle production, size and toxicity in G. mellonella. qRT-PCR analysis of rna01 and putative cognate mRNA targets indicated that Rna01 is associated with the extracytoplasmic stress response. This work increases our understanding of the multilayered and complex nature of the influence of Hfq-dependent sRNAs on the physiology and virulence of A. pleuropneumoniae.
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Affiliation(s)
- Giarlã Cunha da Silva
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária—Bioagro, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Ciro César Rossi
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária—Bioagro, Universidade Federal de Viçosa, Viçosa, Brazil
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Jéssica Nogueira Rosa
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária—Bioagro, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Newton Moreno Sanches
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária—Bioagro, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Daniela Lopes Cardoso
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Yanwen Li
- Section of Pediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Adam A. Witney
- Institute for Infection and Immunity, St. George’s, University of London, London, United Kingdom
| | - Kate A. Gould
- Institute for Infection and Immunity, St. George’s, University of London, London, United Kingdom
| | | | - Anastasia J. Callaghan
- School of Biological Sciences and Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Janine Thérèse Bossé
- Section of Pediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Paul Richard Langford
- Section of Pediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Denise Mara Soares Bazzolli
- Laboratório de Genética Molecular de Bactérias, Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à Agropecuária—Bioagro, Universidade Federal de Viçosa, Viçosa, Brazil
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Roles of the Tol/Pal System in Bacterial Pathogenesis and Its Application to Antibacterial Therapy. Vaccines (Basel) 2022; 10:vaccines10030422. [PMID: 35335056 PMCID: PMC8953051 DOI: 10.3390/vaccines10030422] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 01/27/2023] Open
Abstract
The Tol/Pal system (also written as “The Tol-Pal system”) is a set of protein complexes produced by most Gram-negative bacteria. It comprises the inner membrane-associated and the outer membrane-anchored subunits composed of the TolA, TolQ, and TolR proteins and the TolB and Pal proteins, respectively. Although the Tol/Pal system was first defined as bacterial proteins involved in colicin uptake of Escherichia coli, its global roles have been characterized in several studies as mentioned in this article. Pathogenesis of many Gram-negative pathogens is sustained by the Tol/Pal system. It is also essential for cell growth and fitness in some pathogens. Therefore, the Tol/Pal system is proposed as a potential target for antimicrobial chemotherapy. Although the tol/pal mutants are low in virulence, they still have the ability to stimulate the immune system. The Pal protein is highly immunogenic and induces both adaptive and innate immune responses. Therefore, the tol/pal mutant strains and Pal proteins also have potential vaccine properties. For these reasons, the Tol/Pal system represents a promising research target in the development of antibacterial therapeutic strategies for refractory infections caused by multi-drug-resistant (MDR), Gram-negative pathogens. In this paper, we summarize studies on the Tol/Pal system associated with bacterial pathogenesis and vaccine development.
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Szczepaniak J, Press C, Kleanthous C. The multifarious roles of Tol-Pal in Gram-negative bacteria. FEMS Microbiol Rev 2021; 44:490-506. [PMID: 32472934 PMCID: PMC7391070 DOI: 10.1093/femsre/fuaa018] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022] Open
Abstract
In the 1960s several groups reported the isolation and preliminary genetic mapping of
Escherichia coli strains tolerant towards the
action of colicins. These pioneering studies kick-started two new fields in bacteriology;
one centred on how bacteriocins like colicins exploit the Tol (or more commonly Tol-Pal)
system to kill bacteria, the other on the physiological role of this cell
envelope-spanning assembly. The following half century has seen significant advances in
the first of these fields whereas the second has remained elusive, until recently. Here,
we review work that begins to shed light on Tol-Pal function in Gram-negative bacteria.
What emerges from these studies is that Tol-Pal is an energised system with fundamental,
interlinked roles in cell division – coordinating the re-structuring of peptidoglycan at
division sites and stabilising the connection between the outer membrane and underlying
cell wall. This latter role is achieved by Tol-Pal exploiting the proton motive force to
catalyse the accumulation of the outer membrane peptidoglycan associated lipoprotein Pal
at division sites while simultaneously mobilising Pal molecules from around the cell.
These studies begin to explain the diverse phenotypic outcomes of tol-pal
mutations, point to other cell envelope roles Tol-Pal may have and raise many new
questions.
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Affiliation(s)
- Joanna Szczepaniak
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Cara Press
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Colin Kleanthous
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
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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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Akgul A, Nho SW, Kalindamar S, Tekedar HC, Abdalhamed H, Lawrence ML, Karsi A. Universal Stress Proteins Contribute Edwardsiella ictaluri Virulence in Catfish. Front Microbiol 2018; 9:2931. [PMID: 30546354 PMCID: PMC6279896 DOI: 10.3389/fmicb.2018.02931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 11/14/2018] [Indexed: 11/21/2022] Open
Abstract
Edwardsiella ictaluri is an intracellular Gram-negative facultative pathogen causing enteric septicemia of catfish (ESC), a common disease resulting in substantial economic losses in the U.S. catfish industry. Previously, we demonstrated that several universal stress proteins (USPs) are highly expressed under in vitro and in vivo stress conditions, indicating their importance for E. ictaluri survival. However, the roles of these USPs in E. ictaluri virulence is not known yet. In this work, 10 usp genes of E. ictaluri were in-frame deleted and characterized in vitro and in vivo. Results show that all USP mutants were sensitive to acidic condition (pH 5.5), and EiΔusp05 and EiΔusp08 were very sensitive to oxidative stress (0.1% H2O2). Virulence studies indicated that EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 were attenuated significantly compared to E. ictaluri wild-type (EiWT; 20, 45, 20, 20, 55, and 10% vs. 74.1% mortality, respectively). Efficacy experiments showed that vaccination of catfish fingerlings with EiΔusp05, EiΔusp07, EiΔusp08, EiΔusp09, EiΔusp10, and EiΔusp13 provided complete protection against EiWT compared to sham-vaccinated fish (0% vs. 58.33% mortality). Our results support that USPs contribute E. ictaluri virulence in catfish.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Seong Won Nho
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Safak Kalindamar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Hossam Abdalhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
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Akgul A, Akgul A, Lawrence ML, Karsi A. Stress-related genes promote Edwardsiella ictaluri pathogenesis. PLoS One 2018; 13:e0194669. [PMID: 29554143 PMCID: PMC5858854 DOI: 10.1371/journal.pone.0194669] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/07/2018] [Indexed: 12/22/2022] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative anaerobic rod and the causative agent of enteric septicemia of channel catfish (ESC), which is one of the most prevalent diseases of catfish, causing significant economic losses in the catfish industry. E. ictaluri is resistant to complement system and macrophage killing, which results in rapid systemic septicemia. However, mechanisms of E. ictaluri stress responses under conditions of host environment are not studied well. Therefore, in this work, we report E. ictaluri stress responses during hydrogen peroxide, low pH, and catfish serum stresses as well as during catfish invasion. E. ictaluri stress responses were characterized by identifying expression of 13 universal stress protein (USP) genes (usp01-usp13) and seven USP-interacting protein genes (groEL, groES, dnaK, grpE, and clpB, grpE, relA). Data indicated that three usp genes (usp05, usp07, and usp13) were highly expressed in all stress conditions. Similarly, E. ictaluri heat shock proteins groEL, groES, dnaK, grpE, and clpB were highly expressed in oxidative stress. Also, E. ictaluri grpE and relA were highly expressed in catfish spleen and head kidney. These findings contribute to our understanding of stress response mechanisms in E. ictaluri stress response, and stress-related proteins that are essential for E. ictaluri could be potential targets for live attenuated vaccine development against ESC.
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Affiliation(s)
- Ali Akgul
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Ayfer Akgul
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Mark L. Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States of America
- * E-mail:
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Abdelhamed H, Lawrence ML, Karsi A. The Role of TonB Gene in Edwardsiella ictaluri Virulence. Front Physiol 2017; 8:1066. [PMID: 29326601 PMCID: PMC5741614 DOI: 10.3389/fphys.2017.01066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/04/2017] [Indexed: 11/13/2022] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen that causes enteric septicemia in catfish (ESC). Stress factors including poor water quality, poor diet, rough handling, overcrowding, and water temperature fluctuations increase fish susceptibility to ESC. The TonB energy transducing system (TonB-ExbB-ExbD) and TonB-dependent transporters of Gram-negative bacteria support active transport of scarce resources including iron, an essential micronutrient for bacterial virulence. Deletion of the tonB gene attenuates virulence in several pathogenic bacteria. In the current study, the role of TonB (NT01EI_RS07425) in iron acquisition and E. ictaluri virulence were investigated. To accomplish this, the E. ictaluri tonB gene was in-frame deleted. Growth kinetics, iron utilization, and virulence of the EiΔtonB mutant were determined. Loss of TonB caused a significant reduction in bacterial growth in iron-depleted medium (p > 0.05). The EiΔtonB mutant grew similarly to wild-type E. ictaluri when ferric iron was added to the iron-depleted medium. The EiΔtonB mutant was significantly attenuated in catfish compared with the parent strain (21.69 vs. 46.91% mortality). Catfish surviving infection with EiΔtonB had significant protection against ESC compared with naïve fish (100 vs. 40.47% survival). These findings indicate that TonB participates in pathogenesis of ESC and is an important E. ictaluri virulence factor.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
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