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Hanson BS, Hailemariam A, Yang Y, Mohamed F, Donati GL, Baker D, Sacchettini J, Cai JJ, Subashchandrabose S. Identification of a copper-responsive small molecule inhibitor of uropathogenic Escherichia coli. J Bacteriol 2024:e0011224. [PMID: 38856220 DOI: 10.1128/jb.00112-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 05/10/2024] [Indexed: 06/11/2024] Open
Abstract
Urinary tract infections (UTIs) are a major global health problem and are caused predominantly by uropathogenic Escherichia coli (UPEC). UTIs are a leading cause of prescription antimicrobial use. Incessant increase in antimicrobial resistance in UPEC and other uropathogens poses a serious threat to the current treatment practices. Copper is an effector of nutritional immunity that impedes the growth of pathogens during infection. We hypothesized that copper would augment the toxicity of select small molecules against bacterial pathogens. We conducted a small molecule screening campaign with a library of 51,098 molecules to detect hits that inhibit a UPEC ΔtolC mutant in a copper-dependent manner. A molecule, denoted as E. coli inhibitor or ECIN, was identified as a copper-responsive inhibitor of wild-type UPEC strains. Our gene expression and metal content analysis results demonstrate that ECIN works in concert with copper to exacerbate Cu toxicity in UPEC. ECIN has a broad spectrum of activity against pathogens of medical and veterinary significance including Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus. Subinhibitory levels of ECIN eliminate UPEC biofilm formation. Transcriptome analysis of UPEC treated with ECIN reveals induction of multiple stress response systems. Furthermore, we demonstrate that L-cysteine rescues the growth of UPEC exposed to ECIN. In summary, we report the identification and characterization of a novel copper-responsive small molecule inhibitor of UPEC.IMPORTANCEUrinary tract infection (UTI) is a ubiquitous infectious condition affecting millions of people annually. Uropathogenic Escherichia coli (UPEC) is the predominant etiological agent of UTI. However, UTIs are becoming increasingly difficult to resolve with antimicrobials due to increased antimicrobial resistance in UPEC and other uropathogens. Here, we report the identification and characterization of a novel copper-responsive small molecule inhibitor of UPEC. In addition to E. coli, this small molecule also inhibits pathogens of medical and veterinary significance including Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus.
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Affiliation(s)
- Braden S Hanson
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Amanuel Hailemariam
- Department of Biochemistry and Biophysics, College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas, USA
| | - Yongjian Yang
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Faras Mohamed
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - George L Donati
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Dwight Baker
- Department of Biochemistry and Biophysics, College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas, USA
| | - James Sacchettini
- Department of Biochemistry and Biophysics, College of Agriculture and Life Sciences, Texas A&M University, College Station, Texas, USA
| | - James J Cai
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Sargurunathan Subashchandrabose
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
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2
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Nhu NTK, Rahman MA, Goh KGK, Kim SJ, Phan MD, Peters KM, Alvarez-Fraga L, Hancock SJ, Ravi C, Kidd TJ, Sullivan MJ, Irvine KM, Beatson SA, Sweet MJ, Irwin AD, Vukovic J, Ulett GC, Hasnain SZ, Schembri MA. A convergent evolutionary pathway attenuating cellulose production drives enhanced virulence of some bacteria. Nat Commun 2024; 15:1441. [PMID: 38383596 PMCID: PMC10881479 DOI: 10.1038/s41467-024-45176-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/16/2024] [Indexed: 02/23/2024] Open
Abstract
Bacteria adapt to selective pressure in their immediate environment in multiple ways. One mechanism involves the acquisition of independent mutations that disable or modify a key pathway, providing a signature of adaptation via convergent evolution. Extra-intestinal pathogenic Escherichia coli (ExPEC) belonging to sequence type 95 (ST95) represent a global clone frequently associated with severe human infections including acute pyelonephritis, sepsis, and neonatal meningitis. Here, we analysed a publicly available dataset of 613 ST95 genomes and identified a series of loss-of-function mutations that disrupt cellulose production or its modification in 55.3% of strains. We show the inability to produce cellulose significantly enhances ST95 invasive infection in a rat model of neonatal meningitis, leading to the disruption of intestinal barrier integrity in newborn pups and enhanced dissemination to the liver, spleen and brain. Consistent with these observations, disruption of cellulose production in ST95 augmented innate immune signalling and tissue neutrophil infiltration in a mouse model of urinary tract infection. Mutations that disrupt cellulose production were also identified in other virulent ExPEC STs, Shigella and Salmonella, suggesting a correlative association with many Enterobacteriaceae that cause severe human infection. Together, our findings provide an explanation for the emergence of hypervirulent Enterobacteriaceae clones.
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Affiliation(s)
- Nguyen Thi Khanh Nhu
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - M Arifur Rahman
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia
- QIMR Berghofer Medical Research Institute, Brisbane QLD, Australia
| | - Kelvin G K Goh
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Seung Jae Kim
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Minh-Duy Phan
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Kate M Peters
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Laura Alvarez-Fraga
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, Narbonne, 11100, France
| | - Steven J Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Chitra Ravi
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Central Microbiology, Pathology Queensland, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Katharine M Irvine
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Adam D Irwin
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- University of Queensland Centre for Clinical Research, Brisbane, Australia
- Queensland Children's Hospital, Brisbane, Australia
| | - Jana Vukovic
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia.
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.
| | - Sumaira Z Hasnain
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia.
| | - Mark A Schembri
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia.
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
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3
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Nesse LL, Osland AM, Asal B, Mo SS. Evolution of antimicrobial resistance in E. coli biofilm treated with high doses of ciprofloxacin. Front Microbiol 2023; 14:1246895. [PMID: 37731931 PMCID: PMC10509014 DOI: 10.3389/fmicb.2023.1246895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 08/07/2023] [Indexed: 09/22/2023] Open
Abstract
The evolution of antimicrobial resistance (AMR) has mainly been studied in planktonic bacteria exposed to sub-inhibitory antimicrobial (AM) concentrations. However, in a number of infections that are treated with AMs the bacteria are located in biofilms where they tolerate high doses of AM. In the present study, we continuously exposed biofilm residing E. coli at body temperature to high ciprofloxacin (CIP) concentrations increasing from 4 to 130 times the minimal inhibitory concentration (MIC), i.e., from 0.06 to 2.0 mg/L. After 1 week, the biofilms were full of CIP resistant bacteria. The evolutionary trajectory observed was the same as described in the literature for planktonic bacteria, i.e., starting with a single mutation in the target gene gyrA followed by mutations in parC, gyrB, and parE, as well as in genes for regulation of multidrug efflux pump systems and outer membrane porins. Strains with higher numbers of these mutations also displayed higher MIC values. Furthermore, the evolution of CIP resistance was more rapid, and resulted in strains with higher MIC values, when the bacteria were biofilm residing than when they were in a planktonic suspension. These results may indicate that extensive clinical AM treatment of biofilm-residing bacteria may not only fail to eradicate the infection but also pose an increased risk of AMR development.
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Affiliation(s)
- Live L. Nesse
- Department of Food Safety and Animal Health Research, Norwegian Veterinary Institute, Ås Municipality, Norway
| | - Ane Mohr Osland
- Department of Microbiology, Norwegian Veterinary Institute, Ås Municipality, Norway
| | - Basma Asal
- Department of Bacteriology, Norwegian Veterinary Institute, Ås Municipality, Norway
| | - Solveig Sølverød Mo
- Department of Bacteriology, Norwegian Veterinary Institute, Ås Municipality, Norway
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4
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Bleem A, Prosswimmer T, Chen R, Hady TF, Li J, Bryers JD, Daggett V. Designed α-sheet peptides disrupt uropathogenic E. coli biofilms rendering bacteria susceptible to antibiotics and immune cells. Sci Rep 2023; 13:9272. [PMID: 37286572 PMCID: PMC10247742 DOI: 10.1038/s41598-023-36343-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/01/2023] [Indexed: 06/09/2023] Open
Abstract
Uropathogenic Escherichia coli account for the largest proportion of nosocomial infections in the United States. Nosocomial infections are a major source of increased costs and treatment complications. Many infections are biofilm associated, rendering antibiotic treatments ineffective or cause additional complications (e.g., microbiome depletion). This work presents a potentially complementary non-antibiotic strategy to fight nosocomial infections by inhibiting the formation of amyloid fibrils, a proteinaceous structural reinforcement known as curli in E. coli biofilms. Despite extensive characterization of the fibrils themselves and their associated secretion system, mechanistic details of curli assembly in vivo remain unclear. We hypothesized that, like other amyloid fibrils, curli polymerization involves a unique secondary structure termed "α-sheet". Biophysical studies herein confirmed the presence of α-sheet structure in prefibrillar species of CsgA, the major component of curli, as it aggregated. Binding of synthetic α-sheet peptides to the soluble α-sheet prefibrillar species inhibited CsgA aggregation in vitro and suppressed amyloid fibril formation in biofilms. Application of synthetic α-sheet peptides also enhanced antibiotic susceptibility and dispersed biofilm-resident bacteria for improved uptake by phagocytic cells. The ability of synthetic α-sheet peptides to reduce biofilm formation, improve antibiotic susceptibility, and enhance clearance by macrophages has broad implications for combating biofilm-associated infections.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195, USA
| | - Ruying Chen
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Department of Surgery and Center for Lung Biology, University of Washington, Seattle, WA, 98109, USA
| | - Thomas F Hady
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Jinzheng Li
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - James D Bryers
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Department of Surgery and Center for Lung Biology, University of Washington, Seattle, WA, 98109, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA.
- Molecular Engineering Program, University of Washington, Seattle, WA, 98195, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA.
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5
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Chen YC, Lee WC, Chuang YC. Emerging Non-Antibiotic Options Targeting Uropathogenic Mechanisms for Recurrent Uncomplicated Urinary Tract Infection. Int J Mol Sci 2023; 24:ijms24087055. [PMID: 37108218 PMCID: PMC10138837 DOI: 10.3390/ijms24087055] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 04/06/2023] [Accepted: 04/09/2023] [Indexed: 04/29/2023] Open
Abstract
Urinary tract infections (UTIs) are the most frequent bacterial infections in the clinical setting. Even without underlying anatomic or functional abnormalities, more than 40% of women experience at least one UTI in their lifetime, of which 30% develop recurrent UTIs (rUTIs) within 6 months. Conventional management with antibiotics for rUTIs may eventually lead to the development of multidrug-resistant uropathogens. Targeting of the pathogenicity of rUTIs, the evolution of uropathogenic Escherichia coli (UPEC), and inadequate host defenses by immune responses should be explored to provide non-antibiotic solutions for the management of rUTIs. The adaptive evolution of UPEC has been observed in several aspects, including colonization, attachment, invasion, and intracellular replication to invade the urothelium and survive intracellularly. Focusing on the antivirulence of UPEC and modulating the immunity of susceptible persons, researchers have provided potential alternative solutions in four categories: antiadhesive treatments (i.e., cranberries and D-mannose), immunomodulation therapies, vaccines, and prophylaxis with topical estrogen therapy and probiotics (e.g., Lactobacillus species). Combination therapies targeting multiple pathogenic mechanisms are expected to be a future trend in UTI management, although some of these treatment options have not been well established in terms of their long-term efficacy. Additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques.
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Affiliation(s)
- Yu-Chen Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80756, Taiwan
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80756, Taiwan
- Regenerative Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 80756, Taiwan
| | - Wei-Chia Lee
- Division of Urology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Yao-Chi Chuang
- Division of Urology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
- Center for Shock Wave Medicine and Tissue Engineering, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
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6
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Gu Y, Lu H, Shao Y, Fu D, Wu J, Hu J, Tu J, Song X, Qi K. Acetoacetyl-CoA transferase ydiF regulates the biofilm formation of avian pathogenic Escherichia coli. Res Vet Sci 2022; 153:144-152. [PMID: 36375381 DOI: 10.1016/j.rvsc.2022.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/12/2022] [Accepted: 10/23/2022] [Indexed: 11/06/2022]
Abstract
Avian pathogenic Escherichia coli (APEC) causes persistent infection of poultry and multi-system diseases, which seriously endanger the development of the poultry industry. Biofilm allows bacteria to adapt to the natural environment and plays an important role in resistance to the external environment and the pathogenicity of APEC, but the mechanism of its formation and regulatory network have not been clarified. In this study, we used a Tn5 transposon random mutation library constructed with APEC and identified ydiF, a gene that has not previously been recognized in E. coli biofilm formation. To confirm that the ydiF gene really can regulate the formation of APEC biofilm, the ydiF gene deletion strain was constructed using APEC81. Protein association networks prediction results show that ydiF is mainly associated with genes related to the metabolism of sugars and fatty acids. Deletion of the ydiF gene significantly reduces the formation of APEC biofilm and scanning electron microscopy indicated that the degree of adhesion between the bacteria was also reduced. The deletion of the ydiF gene also significantly reduced the motility of APEC81 and through transmission electron microscopy APEC81 was observed to have significantly fewer flagella. However, the colony morphology of APEC81 on Congo red and Coomassie brilliant blue media was unaffected. The results of fluorescence quantification showed that the deletion of the ydiF gene caused a down-regulation in the transcription of genes related to the second messenger, sugar metabolism, and quorum sensing. These results indicate that ydiF plays an important role in biofilm formation and the movement of APEC. In addition, it may be possible to regulate the formation of APEC biofilms by different methods such as by regulating the second messenger and metabolic system.
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Affiliation(s)
- Yi Gu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Huiqi Lu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Dandan Fu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jianmei Wu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jiangang Hu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Hefei 230036, Anhui, China.
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7
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Schüroff PA, Abe CM, Silva JW, de Paula Coelho C, Andrade FB, Hernandes RT, Dobrindt U, Gomes TAT, Elias WP. Role of aggregate-forming pilus (AFP) in adherence and colonization of both intestinal and urinary tracts. Virulence 2022; 13:1423-1433. [PMID: 35982607 PMCID: PMC9397481 DOI: 10.1080/21505594.2022.2112818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hybrid-pathogenic Escherichia coli represent an important group of strains associated with intestinal and extraintestinal infections. Recently, we described strain UPEC-46, a uropathogenic/enteroaggregative E. coli (UPEC/EAEC) strain presenting the aggregative adherence (AA) pattern on bladder and colorectal epithelial cells mediated by aggregate-forming pili (AFP). However, the role of AFP and other uninvestigated putative fimbriae operons in UPEC-46 pathogenesis remains unclear. Thus, this study evaluated the involvement of AFP and other adhesins in uropathogenicity and intestinal colonization using different in vitro and in vivo models. The strain UPEC-46 was able to adhere and invade intestinal and urinary cell lines. A library of transposon mutants also identified the involvement of type I fimbriae (TIF) in the adherence to HeLa cells, in addition to colorectal and bladder cell lines. The streptomycin-treated mouse in vivo model also showed an increased number of bacterial counts in the colon in the presence of AFP and TIF. In the mouse model of ascending urinary tract infection (UTI), AFP was more associated with kidney colonization, while TIF appears to mediate bladder colonization. Results observed in in vivo experiments were also confirmed by electron microscopy (EM) analyses. In summary, the in vitro and in vivo analyses show a synergistic role of AFP and TIF in the adherence and colonization of intestinal and urinary epithelia. Therefore, we propose that hybrid E. coli strains carrying AFP and TIF could potentially cause intestinal and urinary tract infections in the same patient.
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Affiliation(s)
- Paulo A Schüroff
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil.,Institute of Hygiene, University of Münster, Münster, Germany
| | - Cecilia M Abe
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Jonatas W Silva
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Cidéli de Paula Coelho
- Departamento de Pós-graduação, Faculdade de Medicina Veterinária, Universidade Santo Amaro, São Paulo, Brazil
| | | | - Rodrigo T Hernandes
- Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, Brazil
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
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8
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Dawadi P, Khanal S, Prasai Joshi T, KC S, Tuladhar R, Maharjan BL, Darai A, Joshi DR. Antibiotic Resistance, Biofilm Formation and Sub-Inhibitory Hydrogen Peroxide Stimulation in Uropathogenic Escherichia coli. Microbiol Insights 2022; 15:11786361221135224. [PMID: 36420183 PMCID: PMC9677168 DOI: 10.1177/11786361221135224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/06/2022] [Indexed: 11/12/2023] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the most prevalent cause of urinary tract infections (UTIs). Biofilm formation and antibiotic resistance could be high among the causative agent. The purpose of this study was to determine antibiotic resistance, biofilm production, and biofilm-associated genes, bcsA and csgD, and sub-inhibitory hydrogen peroxide (H2O2) stimulation in UPEC for biofilm formation. A total of 71 UPEC were collected from a tertiary care hospital in Kathmandu and subjected to identify antibiotic susceptibility using Kirby-Bauer disk diffusion. The biofilm formation was assessed using microtiter culture plate method while pellicle formation was tested by a tube method. In representative 15 isolates based on biofilm-forming ability, bcsA and csgD were screened by conventional polymerase chain reaction, and treated with sub-lethal H2O2. The UPEC were found the most susceptible to meropenem (90.2%), and the least to ampicillin (11.3%) in vitro and 90.1% of them were multi-drug resistant (MDR). Most UPEC harbored biofilm-producing ability (97.2%), and could form pellicle at 37°C. Among representative 15 isolates, csgD was detected only among 10 isolates (66.67%) while bcsA gene was present in 13 isolates (86.67%). This study revealed that level of biofilm production elevated after sub-lethal H2O2 treatment (P = .041). These findings suggested that the pathogens are emerging as MDR. The biofilm production is high and the majority of selected strains contained bcsA and csgD genes. Pellicle formation test was suggestive to be an alternative qualitative method to screen biofilm production in UPEC. The sub-inhibitory concentration of H2O2 may contribute in increasing biofilm formation in UPEC.
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Affiliation(s)
- Prabin Dawadi
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Santosh Khanal
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Tista Prasai Joshi
- Faculty of Science, Nepal Academy of Science and Technology, Khumaltar, Lalitpur, Nepal
| | - Sudeep KC
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Reshma Tuladhar
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Bijaya Laxmi Maharjan
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Anjani Darai
- Department of Pathology, Bharosa Hospital, Mid-Baneswor, Kathmandu, Nepal
| | - Dev Raj Joshi
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
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9
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Redox-Mediated Inactivation of the Transcriptional Repressor RcrR is Responsible for Uropathogenic Escherichia coli's Increased Resistance to Reactive Chlorine Species. mBio 2022; 13:e0192622. [PMID: 36073817 PMCID: PMC9600549 DOI: 10.1128/mbio.01926-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The ability to overcome stressful environments is critical for pathogen survival in the host. One challenge for bacteria is the exposure to reactive chlorine species (RCS), which are generated by innate immune cells as a critical part of the oxidative burst. Hypochlorous acid (HOCl) is the most potent antimicrobial RCS and is associated with extensive macromolecular damage in the phagocytized pathogen. However, bacteria have evolved defense strategies to alleviate the effects of HOCl-mediated damage. Among these are RCS-sensing transcriptional regulators that control the expression of HOCl-protective genes under non-stress and HOCl stress. Uropathogenic Escherichia coli (UPEC), the major causative agent of urinary tract infections (UTIs), is particularly exposed to infiltrating neutrophils during pathogenesis; however, their responses to and defenses from HOCl are still completely unexplored. Here, we present evidence that UPEC strains tolerate higher levels of HOCl and are better protected from neutrophil-mediated killing compared with other E. coli. Transcriptomic analysis of HOCl-stressed UPEC revealed the upregulation of an operon consisting of three genes, one of which encodes the transcriptional regulator RcrR. We identified RcrR as a HOCl-responsive transcriptional repressor, which, under non-stress conditions, is bound to the operator and represses the expression of its target genes. During HOCl exposure, however, the repressor forms reversible intermolecular disulfide bonds and dissociates from the DNA resulting in the derepression of the operon. Deletion of one of the target genes renders UPEC significantly more susceptible to HOCl and phagocytosis indicating that the HOCl-mediated induction of the regulon plays a major role for UPEC’s HOCl resistance.
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10
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Torres-Puig S, García V, Stærk K, Andersen TE, Møller-Jensen J, Olsen JE, Herrero-Fresno A. “Omics” Technologies - What Have They Told Us About Uropathogenic Escherichia coli Fitness and Virulence During Urinary Tract Infection? Front Cell Infect Microbiol 2022; 12:824039. [PMID: 35237532 PMCID: PMC8882828 DOI: 10.3389/fcimb.2022.824039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the main etiological agent of urinary tract infection (UTI), a widespread infectious disease of great impact on human health. This is further emphasized by the rapidly increase in antimicrobial resistance in UPEC, which compromises UTI treatment. UPEC biology is highly complex since uropathogens must adopt extracellular and intracellular lifestyles and adapt to different niches in the host. In this context, the implementation of forefront ‘omics’ technologies has provided substantial insight into the understanding of UPEC pathogenesis, which has opened the doors for new therapeutics and prophylactics discovery programs. Thus, ‘omics’ technologies applied to studies of UPEC during UTI, or in models of UTI, have revealed extensive lists of factors that are important for the ability of UPEC to cause disease. The multitude of large ‘omics’ datasets that have been generated calls for scrutinized analysis of specific factors that may be of interest for further development of novel treatment strategies. In this review, we describe main UPEC determinants involved in UTI as estimated by ‘omics’ studies, and we compare prediction of factors across the different ‘omics’ technologies, with a focus on those that have been confirmed to be relevant under UTI-related conditions. We also discuss current challenges and future perspectives regarding analysis of data to provide an overview and better understanding of UPEC mechanisms involved in pathogenesis which should assist in the selection of target sites for future prophylaxis and treatment.
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Affiliation(s)
- Sergi Torres-Puig
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Vanesa García
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
- Laboratorio de Referencia de Escherichia coli (LREC), Departamento de Microbioloxía e Parasitoloxía, Facultade de Veterinaria, Universidade de Santiago de Compostela (USC), Lugo, Spain
| | - Kristian Stærk
- Research Unit of Clinical Microbiology, University of Southern Denmark and Odense University Hospital, Odense, Denmark
| | - Thomas E. Andersen
- Research Unit of Clinical Microbiology, University of Southern Denmark and Odense University Hospital, Odense, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - John E. Olsen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Ana Herrero-Fresno
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
- *Correspondence: Ana Herrero-Fresno,
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11
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Mehershahi KS, Chen SL. DNA methylation by three Type I restriction modification systems of Escherichia coli does not influence gene regulation of the host bacterium. Nucleic Acids Res 2021; 49:7375-7388. [PMID: 34181709 PMCID: PMC8287963 DOI: 10.1093/nar/gkab530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/01/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
DNA methylation is a common epigenetic mark that influences transcriptional regulation, and therefore cellular phenotype, across all domains of life. In particular, both orphan methyltransferases and those from phasevariable restriction modification systems (RMSs) have been co-opted to regulate virulence epigenetically in many bacteria. We now show that three distinct non-phasevariable Type I RMSs in Escherichia coli have no measurable impact on gene expression, in vivo virulence, or any of 1190 in vitro growth phenotypes. We demonstrated this using both Type I RMS knockout mutants as well as heterologous installation of Type I RMSs into two E. coli strains. These data provide three clear and currently rare examples of restriction modification systems that have no impact on their host organism’s gene regulation. This leads to the possibility that other such nonregulatory methylation systems may exist, broadening our view of the potential role that RMSs may play in bacterial evolution.
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Affiliation(s)
- Kurosh S Mehershahi
- NUHS Infectious Diseases Translational Research Programme, Department of Medicine, Division of Infectious Diseases, Yong Loo Lin School of Medicine, Singapore 119228
| | - Swaine L Chen
- NUHS Infectious Diseases Translational Research Programme, Department of Medicine, Division of Infectious Diseases, Yong Loo Lin School of Medicine, Singapore 119228.,Laboratory of Bacterial Genomics, Genome Institute of Singapore, Singapore 138672
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12
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Renoz F, Foray V, Ambroise J, Baa-Puyoulet P, Bearzatto B, Mendez GL, Grigorescu AS, Mahillon J, Mardulyn P, Gala JL, Calevro F, Hance T. At the Gate of Mutualism: Identification of Genomic Traits Predisposing to Insect-Bacterial Symbiosis in Pathogenic Strains of the Aphid Symbiont Serratia symbiotica. Front Cell Infect Microbiol 2021; 11:660007. [PMID: 34268133 PMCID: PMC8275996 DOI: 10.3389/fcimb.2021.660007] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/14/2021] [Indexed: 01/10/2023] Open
Abstract
Mutualistic associations between insects and heritable bacterial symbionts are ubiquitous in nature. The aphid symbiont Serratia symbiotica is a valuable candidate for studying the evolution of bacterial symbiosis in insects because it includes a wide diversity of strains that reflect the diverse relationships in which bacteria can be engaged with insects, from pathogenic interactions to obligate intracellular mutualism. The recent discovery of culturable strains, which are hypothesized to resemble the ancestors of intracellular strains, provide an opportunity to study the mechanisms underlying bacterial symbiosis in its early stages. In this study, we analyzed the genomes of three of these culturable strains that are pathogenic to aphid hosts, and performed comparative genomic analyses including mutualistic host-dependent strains. All three genomes are larger than those of the host-restricted S. symbiotica strains described so far, and show significant enrichment in pseudogenes and mobile elements, suggesting that these three pathogenic strains are in the early stages of the adaptation to their host. Compared to their intracellular mutualistic relatives, the three strains harbor a greater diversity of genes coding for virulence factors and metabolic pathways, suggesting that they are likely adapted to infect new hosts and are a potential source of metabolic innovation for insects. The presence in their genomes of secondary metabolism gene clusters associated with the production of antimicrobial compounds and phytotoxins supports the hypothesis that S. symbiotia symbionts evolved from plant-associated strains and that plants may serve as intermediate hosts. Mutualistic associations between insects and bacteria are the result of independent transitions to endosymbiosis initiated by the acquisition of environmental progenitors. In this context, the genomes of free-living S. symbiotica strains provide a rare opportunity to study the inventory of genes held by bacterial associates of insects that are at the gateway to a host-dependent lifestyle.
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Affiliation(s)
- François Renoz
- Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - Vincent Foray
- Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
- Institut de Recherche sur la Biologie de l’insecte, UMR 7261, CNRS, Université de Tours, Tours, France
| | - Jérôme Ambroise
- Center for Applied Molecular Technologies, Institute of Experimental and Clinical Research, Université catholique de Louvain (UCLouvain), Woluwe-Saint-Lambert, Belgium
| | | | - Bertrand Bearzatto
- Center for Applied Molecular Technologies, Institute of Experimental and Clinical Research, Université catholique de Louvain (UCLouvain), Woluwe-Saint-Lambert, Belgium
| | - Gipsi Lima Mendez
- Louvain Institute of Biomolecular Science and Technology (LIBST), Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | | | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
| | - Patrick Mardulyn
- Evolutionary Biology and Ecology, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Luc Gala
- Center for Applied Molecular Technologies, Institute of Experimental and Clinical Research, Université catholique de Louvain (UCLouvain), Woluwe-Saint-Lambert, Belgium
| | - Federica Calevro
- Univ Lyon, INSA-Lyon, INRAE, BF2i, UMR203, F-69621, Villeurbanne, France
| | - Thierry Hance
- Biodiversity Research Centre, Earth and Life Institute, Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium
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13
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Hemmati F, Rezaee MA, Ebrahimzadeh S, Yousefi L, Nouri R, Kafil HS, Gholizadeh P. Novel Strategies to Combat Bacterial Biofilms. Mol Biotechnol 2021; 63:569-586. [PMID: 33914260 DOI: 10.1007/s12033-021-00325-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 04/09/2021] [Indexed: 12/15/2022]
Abstract
Biofilms are considered as a severe problem in the treatment of bacterial infections; their development causes some noticeable resistance to antibacterial agents. Biofilms are responsible for at least two-thirds of all infections, displaying promoted resistance to classical antibiotic treatments. Therefore, finding new alternative therapeutic approaches is essential for the treatment and inhibition of biofilm-related infections. Therefore, this review aims to describe the potential therapeutic strategies that can inhibit bacterial biofilm development; these include the usage of antiadhesion agents, AMPs, bacteriophages, QSIs, aptamers, NPs and PNAs, which can prevent or eradicate the formation of biofilms. These antibiofilm agents represent a promising therapeutic target in the treatment of biofilm infections and development of a strong capability to interfere with different phases of the biofilm development, including adherence, polysaccharide intercellular adhesion (PIA), quorum sensing molecules and cell-to-cell connection, bacterial aggregation, planktonic bacteria killing and host-immune response modulation. In addition, these components, in combination with antibiotics, can lead to the development of some kind of powerful combined therapy against bacterial biofilm-related infections.
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Affiliation(s)
- Fatemeh Hemmati
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Saba Ebrahimzadeh
- Department of Food Science and Technology, Faculty of Agriculture and Natural Resources, Urmia University, Urmia, Iran
| | - Leila Yousefi
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Roghayeh Nouri
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Samadi Kafil
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Pourya Gholizadeh
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
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14
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Beebout CJ, Sominsky LA, Eberly AR, Van Horn GT, Hadjifrangiskou M. Cytochrome bd promotes Escherichia coli biofilm antibiotic tolerance by regulating accumulation of noxious chemicals. NPJ Biofilms Microbiomes 2021; 7:35. [PMID: 33863914 PMCID: PMC8052454 DOI: 10.1038/s41522-021-00210-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/16/2021] [Indexed: 02/02/2023] Open
Abstract
Nutrient gradients in biofilms cause bacteria to organize into metabolically versatile communities capable of withstanding threats from external agents including bacteriophages, phagocytes, and antibiotics. We previously determined that oxygen availability spatially organizes respiration in uropathogenic Escherichia coli biofilms, and that the high-affinity respiratory quinol oxidase cytochrome bd is necessary for extracellular matrix production and biofilm development. In this study we investigate the physiologic consequences of cytochrome bd deficiency in biofilms and determine that loss of cytochrome bd induces a biofilm-specific increase in expression of general diffusion porins, leading to elevated outer membrane permeability. In addition, loss of cytochrome bd impedes the proton mediated efflux of noxious chemicals by diminishing respiratory flux. As a result, loss of cytochrome bd enhances cellular accumulation of noxious chemicals and increases biofilm susceptibility to antibiotics. These results identify an undescribed link between E. coli biofilm respiration and stress tolerance, while suggesting the possibility of inhibiting cytochrome bd as an antibiofilm therapeutic approach.
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Affiliation(s)
- Connor J. Beebout
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Levy A. Sominsky
- grid.152326.10000 0001 2264 7217Vanderbilt University, Nashville, TN USA
| | - Allison R. Eberly
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA ,grid.66875.3a0000 0004 0459 167XPresent Address: Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN USA
| | - Gerald T. Van Horn
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Maria Hadjifrangiskou
- grid.412807.80000 0004 1936 9916Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA ,grid.412807.80000 0004 1936 9916Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN USA
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15
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Miller AL, Bessho S, Grando K, Tükel Ç. Microbiome or Infections: Amyloid-Containing Biofilms as a Trigger for Complex Human Diseases. Front Immunol 2021; 12:638867. [PMID: 33717189 PMCID: PMC7952436 DOI: 10.3389/fimmu.2021.638867] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/09/2021] [Indexed: 12/14/2022] Open
Abstract
The human microbiota is the community of microorganisms that live upon or within their human host. The microbiota consists of various microorganisms including bacteria, fungi, viruses, and archaea; the gut microbiota is comprised mostly of bacteria. Many bacterial species within the gut microbiome grow as biofilms, which are multicellular communities embedded in an extracellular matrix. Studies have shown that the relative abundances of bacterial species, and therefore biofilms and bacterial byproducts, change during progression of a variety of human diseases including gastrointestinal, autoimmune, neurodegenerative, and cancer. Studies have shown the location and proximity of the biofilms within the gastrointestinal tract might impact disease outcome. Gram-negative enteric bacteria secrete the amyloid curli, which makes up as much as 85% of the extracellular matrix of enteric biofilms. Curli mediates cell-cell attachment and attachment to various surfaces including extracellular matrix components such as fibronectin and laminin. Structurally, curli is strikingly similar to pathological and immunomodulatory human amyloids such as amyloid-β, which has been implicated in Alzheimer's disease, α-synuclein, which is involved in Parkinson's disease, and serum amyloid A, which is secreted during the acute phase of inflammation. The immune system recognizes both bacterial amyloid curli and human amyloids utilizing the same receptors, so curli also induces inflammation. Moreover, recent work indicates that curli can participate in the self-assembly process of pathological human amyloids. Curli is found within biofilms of commensal enteric bacteria as well as invasive pathogens; therefore, evidence suggests that curli contributes to complex human diseases. In this review, we summarize the recent findings on how bacterial biofilms containing curli participate in the pathological and immunological processes in gastrointestinal diseases, systemic autoimmune diseases, and neurodegenerative diseases.
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Affiliation(s)
- Amanda L Miller
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Shingo Bessho
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Kaitlyn Grando
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Çagla Tükel
- Department of Microbiology and Immunology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
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16
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Adaptation of Arginine Synthesis among Uropathogenic Branches of the Escherichia coli Phylogeny Reveals Adjustment to the Urinary Tract Habitat. mBio 2020; 11:mBio.02318-20. [PMID: 32994329 PMCID: PMC7527732 DOI: 10.1128/mbio.02318-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the most common cause of human urinary tract infection (UTI). Population bottlenecks during early stages of UTI make high-throughput screens impractical for understanding clinically important later stages of UTI, such as persistence and recurrence. As UPEC is hypothesized to be adapted to these later pathogenic stages, we previously identified 29 genes evolving under positive selection in UPEC. Here, we found that 8 of these genes, including argI (which is involved in arginine biosynthesis), are important for persistence in a mouse model of UTI. Deletion of argI and other arginine synthesis genes resulted in (i) arginine auxotrophy and (ii) defects in persistent UTI. Replacement of a B2 clade argI with a non-B2 clade argI complemented arginine auxotrophy, but the resulting strain remained attenuated in its ability to cause persistent bacteriuria. Thus, argI may have a second function during UTI that is not related to simple arginine synthesis. This study demonstrates how variation in metabolic genes can impact virulence and provides insight into the mechanisms and evolution of bacterial virulence. Urinary tract infections (UTIs) are predominantly caused by uropathogenic Escherichia coli (UPEC). UPEC pathogenesis requires passage through a severe population bottleneck involving intracellular bacterial communities (IBCs) that are clonal expansions of a single invading UPEC bacterium in a urothelial superficial facet cell. IBCs occur only during acute pathogenesis. The bacteria in IBCs form the founder population that develops into persistent extracellular infections. Only a small fraction of UPEC organisms proceed through the IBC cycle, regardless of the inoculum size. This dramatic reduction in population size precludes the utility of genomic mutagenesis technologies for identifying genes important for persistence. To circumvent this bottleneck, we previously identified 29 positively selected genes (PSGs) within UPEC and hypothesized that they contribute to virulence. Here, we show that 8 of these 29 PSGs are required for fitness during persistent bacteriuria. Conversely, 7/8 of these PSG mutants showed essentially no phenotype in acute UTI. Deletion of the PSG argI leads to arginine auxotrophy. Relative to the other arg genes, argI in the B2 clade (which comprises most UPEC strains) of E. coli has diverged from argI in other E. coli clades. Replacement of argI in a UPEC strain with a non-UPEC argI allele complemented the arginine auxotrophy but not the persistent bacteriuria defect, showing that the UPEC argI allele contributes to persistent infection. These results highlight the complex roles of metabolic pathways during infection and demonstrate that evolutionary approaches can identify infection-specific gene functions downstream of population bottlenecks, shedding light on virulence and the genetic evolution of pathogenesis.
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17
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Jeffries J, Thongsomboon W, Visser JA, Enriquez K, Yager D, Cegelski L. Variation in the ratio of curli and phosphoethanolamine cellulose associated with biofilm architecture and properties. Biopolymers 2020; 112:e23395. [PMID: 32894594 DOI: 10.1002/bip.23395] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 11/11/2022]
Abstract
Bacterial biofilms are communities of bacteria entangled in a self-produced extracellular matrix (ECM). Escherichia coli direct the assembly of two insoluble biopolymers, curli amyloid fibers, and phosphoethanolamine (pEtN) cellulose, to build remarkable biofilm architectures. Intense curiosity surrounds how bacteria harness these amyloid-polysaccharide composites to build biofilms, and how these biopolymers function to benefit bacterial communities. Defining ECM composition involving insoluble polymeric assemblies poses unique challenges to analysis and, thus, to comparing strains with quantitative ECM molecular correlates. In this work, we present results from a sum-of-the-parts 13 C solid-state nuclear magnetic resonance (NMR) analysis to define the curli-to-pEtN cellulose ratio in the isolated ECM of the E. coli laboratory K12 strain, AR3110. We compare and contrast the compositional analysis and comprehensive biofilm phenotypes for AR3110 and a well-studied clinical isolate, UTI89. The ECM isolated from AR3110 contains approximately twice the amount of pEtN cellulose relative to curli content as UTI89, revealing plasticity in matrix assembly principles among strains. The two parent strains and a panel of relevant gene mutants were investigated in three biofilm models, examining: (a) macrocolonies on agar, (b) pellicles at the liquid-air interface, and (c) biomass accumulation on plastic. We describe the influence of curli, cellulose, and the pEtN modification on biofilm phenotypes with power in the direct comparison of these strains. The results suggest that curli more strongly influence adhesion, while pEtN cellulose drives cohesion. Their individual and combined influence depends on both the biofilm modality (agar, pellicle, or plastic-associated) and the strain itself.
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Affiliation(s)
- Jamie Jeffries
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, California, USA
| | | | | | - Kyle Enriquez
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Deborah Yager
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California, USA
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18
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Ogasawara H, Ishizuka T, Hotta S, Aoki M, Shimada T, Ishihama A. Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12. Microbiology (Reading) 2020; 166:880-890. [DOI: 10.1099/mic.0.000947] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Under stressful conditions,
Escherichia coli
forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study ‘promoter-specific transcription-factor’ (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.
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Affiliation(s)
- Hiroshi Ogasawara
- Academic Assembly School of Humanities and Social Sciences Institute of Humanities, Shinshu University, Asahi 3-1-1, Matsumoto, 390–8621, Japan
- Research Center for Supports to Advanced Science, Division of Gene Research, Shinshu University, Ueda, Nagano 386-8567, Japan
| | - Toshiyuki Ishizuka
- Research Center for Supports to Advanced Science, Division of Gene Research, Shinshu University, Ueda, Nagano 386-8567, Japan
| | - Shuhei Hotta
- Research Center for Supports to Advanced Science, Division of Gene Research, Shinshu University, Ueda, Nagano 386-8567, Japan
| | - Michiko Aoki
- Research Center for Supports to Advanced Science, Division of Gene Research, Shinshu University, Ueda, Nagano 386-8567, Japan
| | - Tomohiro Shimada
- School of Agriculture, Meiji University, 1-1-1 Higashi Mita, Tama-ku, Kawasaki, Kanagawa 214–8571, Japan
| | - Akira Ishihama
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
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19
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Escherichia coli CFT073 Fitness Factors during Urinary Tract Infection: Identification Using an Ordered Transposon Library. Appl Environ Microbiol 2020; 86:AEM.00691-20. [PMID: 32358013 DOI: 10.1128/aem.00691-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 04/24/2020] [Indexed: 12/15/2022] Open
Abstract
Urinary tract infections (UTI), the second most diagnosed infectious disease worldwide, are caused primarily by uropathogenic Escherichia coli (UPEC), placing a significant financial burden on the health care system. High-throughput transposon mutagenesis combined with genome-targeted sequencing is a powerful technique to interrogate genomes for fitness genes. Genome-wide analysis of E. coli requires random libraries of at least 50,000 mutants to achieve 99.99% saturation; however, the traditional murine model of ascending UTI does not permit testing of large mutant pools due to a bottleneck during infection. To address this, an E. coli CFT073 transposon mutant ordered library of 9,216 mutants was created and insertion sites were identified. A single transposon mutant was selected for each gene to assemble a condensed library consisting of 2,913 unique nonessential mutants. Using a modified UTI model in BALB/c mice, we identified 36 genes important for colonizing the bladder, including purB, yihE, and carB Screening of the condensed library in vitro identified yigP and ubiG to be essential for growth in human urine. Additionally, we developed a novel quantitative PCR (qPCR) technique to identify genes with fitness defects within defined subgroups of related genes (e.g., genes encoding fimbriae, toxins, etc.) following UTI. The number of mutants within these subgroups circumvents bottleneck restriction and facilitates validation of multiple mutants to generate individual competitive indices. Collectively, this study investigates the bottleneck effects during UTI, provides two techniques for evading those effects that can be applied to other disease models, and contributes a genetic tool in prototype strain CFT073 to the field.IMPORTANCE Uropathogenic Escherichia coli strains cause most uncomplicated urinary tract infections (UTI), one of the most common infectious diseases worldwide. Random transposon mutagenesis techniques have been utilized to identify essential bacterial genes during infection; however, this has been met with limitations when applied to the murine UTI model. Conventional high-throughput transposon mutagenesis screens are not feasible because of inoculum size restrictions due to a bottleneck during infection. Our study utilizes a condensed ordered transposon library, limiting the number of mutants while maintaining the largest possible genome coverage. Screening of this library in vivo, and in human urine in vitro, identified numerous candidate fitness factors. Additionally, we have developed a novel technique using qPCR to quantify bacterial outputs following infection with small subgroups of transposon mutants. Molecular approaches developed in this study will serve as useful tools to probe in vivo models that are restricted by anatomical, physiological, or genetic bottleneck limitations.
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20
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Eberly AR, Beebout CJ, Carmen Tong CM, Van Horn GT, Green HD, Fitzgerald MJ, De S, Apple EK, Schrimpe-Rutledge AC, Codreanu SG, Sherrod SD, McLean JA, Clayton DB, Stratton CW, Schmitz JE, Hadjifrangiskou M. Defining a Molecular Signature for Uropathogenic versus Urocolonizing Escherichia coli: The Status of the Field and New Clinical Opportunities. J Mol Biol 2019; 432:786-804. [PMID: 31794727 DOI: 10.1016/j.jmb.2019.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 10/21/2019] [Accepted: 11/13/2019] [Indexed: 01/05/2023]
Abstract
Urinary tract infections (UTIs) represent a major burden across the population, although key facets of their pathophysiology and host interaction remain unclear. Escherichia coli epitomizes these obstacles: this gram-negative bacterial species is the most prevalent agent of UTIs worldwide and can also colonize the urogenital tract in a phenomenon known as asymptomatic bacteriuria (ASB). Unfortunately, at the level of the individual E. coli strains, the relationship between UTI and ASB is poorly defined, confounding our understanding of microbial pathogenesis and strategies for clinical management. Unlike diarrheagenic pathotypes of E. coli, the definition of uropathogenic E. coli (UPEC) remains phenomenologic, without conserved phenotypes and known genetic determinants that rigorously distinguish UTI- and ASB-associated strains. This article provides a cross-disciplinary review of the current issues from interrelated mechanistic and diagnostic perspectives and describes new opportunities by which clinical resources can be leveraged to overcome molecular challenges. Specifically, we present our work harnessing a large collection of patient-derived isolates to identify features that do (and do not) distinguish UTI- from ASB-associated E. coli strains. Analyses of biofilm formation, previously reported to be higher in ASB strains, revealed extensive phenotypic heterogeneity that did not correlate with symptomatology. However, metabolomic experiments revealed distinct signatures between ASB and cystitis isolates, including in the purine pathway (previously shown to be critical for intracellular survival during acute infection). Together, these studies demonstrate how large-scale, wild-type approaches can help dissect the physiology of colonization versus infection, suggesting that the molecular definition of UPEC may rest at the level of global bacterial metabolism.
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Affiliation(s)
- Allison R Eberly
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Connor J Beebout
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ching Man Carmen Tong
- Division of Pediatric Urology, Department of Urology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Gerald T Van Horn
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hamilton D Green
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Madison J Fitzgerald
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shuvro De
- Division of Pediatric Urology, Department of Urology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emily K Apple
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Simona G Codreanu
- Center for Innovative Technologies, Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Stacy D Sherrod
- Center for Innovative Technologies, Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - John A McLean
- Center for Innovative Technologies, Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Douglass B Clayton
- Division of Pediatric Urology, Department of Urology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Charles W Stratton
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Division of Laboratory Medicine, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute for Infection, Immunology & Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jonathan E Schmitz
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Division of Laboratory Medicine, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute for Infection, Immunology & Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Maria Hadjifrangiskou
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute for Infection, Immunology & Inflammation (VI4), Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Hypervirulent Klebsiella pneumoniae serotype K1 clinical isolates form robust biofilms at the air-liquid interface. PLoS One 2019; 14:e0222628. [PMID: 31532800 PMCID: PMC6750583 DOI: 10.1371/journal.pone.0222628] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 09/04/2019] [Indexed: 01/10/2023] Open
Abstract
The prevalence of a new hypervirulent and hypermucoviscous K. pneumoniae phenotype (Hmv) is increasing worldwide, mainly linked to serotypes K1 and K2. Since capsular thickness can directly affect the capability to form biofilms, we aimed to evaluate the association between the Hmv phenotype with adhesion and biofilm formation in a collection of clinical K. pneumoniae isolates. We selected 38 Hmv clinical isolates [15 serotype K1; 9 serotype K2; 3 non-K1/K2 (rmpA+); 11 non-K1/K2 (rmpA-)] and 7 non-Hmv clinical isolates. The Hmv phenotype was assessed through the mucoviscosity test. Serum resistance was determined by bacterial viability tests in pooled human serum. Adhesion was evaluated with the Biofilm Ring Test®, and biofilm formation was identified by crystal violet staining (Solid-Liquid, SLI-biofilm) or visual examination (Air-Liquid, ALI-biofilm). This study linked for the first time the formation of robust ALI-biofilm plugs by K. pneumoniae to the capsular serotype K1, a group of hypervirulent strains which are generally highly susceptible to the antimicrobial agents. Among all the studied isolates, the capsular serotype K1 presented lower initial adhesion despite having the adhesins mrkD and fimH but higher ALI-biofilm formation than isolates with other capsular serotypes (K2 or non-K1/K2). This structure might confer increased resistance to a group of hypervirulent K. pneumoniae serotype K1.
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Warr AR, Hubbard TP, Munera D, Blondel CJ, Abel zur Wiesch P, Abel S, Wang X, Davis BM, Waldor MK. Transposon-insertion sequencing screens unveil requirements for EHEC growth and intestinal colonization. PLoS Pathog 2019; 15:e1007652. [PMID: 31404118 PMCID: PMC6705877 DOI: 10.1371/journal.ppat.1007652] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/22/2019] [Accepted: 08/01/2019] [Indexed: 12/28/2022] Open
Abstract
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is an important food-borne pathogen that colonizes the colon. Transposon-insertion sequencing (TIS) was used to identify genes required for EHEC and E. coli K-12 growth in vitro and for EHEC growth in vivo in the infant rabbit colon. Surprisingly, many conserved loci contribute to EHEC's but not to K-12's growth in vitro. There was a restrictive bottleneck for EHEC colonization of the rabbit colon, which complicated identification of EHEC genes facilitating growth in vivo. Both a refined version of an existing analytic framework as well as PCA-based analysis were used to compensate for the effects of the infection bottleneck. These analyses confirmed that the EHEC LEE-encoded type III secretion apparatus is required for growth in vivo and revealed that only a few effectors are critical for in vivo fitness. Over 200 mutants not previously associated with EHEC survival/growth in vivo also appeared attenuated in vivo, and a subset of these putative in vivo fitness factors were validated. Some were found to contribute to efficient type-three secretion while others, including tatABC, oxyR, envC, acrAB, and cvpA, promote EHEC resistance to host-derived stresses. cvpA is also required for intestinal growth of several other enteric pathogens, and proved to be required for EHEC, Vibrio cholerae and Vibrio parahaemolyticus resistance to the bile salt deoxycholate, highlighting the important role of this previously uncharacterized protein in pathogen survival. Collectively, our findings provide a comprehensive framework for understanding EHEC growth in the intestine.
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Affiliation(s)
- Alyson R. Warr
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Troy P. Hubbard
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Diana Munera
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carlos J. Blondel
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pia Abel zur Wiesch
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sören Abel
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xiaoxue Wang
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brigid M. Davis
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Matthew K. Waldor
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
- HHMI, Boston, Massachusetts, United States of America
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Adaptation Through Lifestyle Switching Sculpts the Fitness Landscape of Evolving Populations: Implications for the Selection of Drug-Resistant Bacteria at Low Drug Pressures. Genetics 2019; 211:1029-1044. [PMID: 30670539 DOI: 10.1534/genetics.119.301834] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/16/2019] [Indexed: 12/21/2022] Open
Abstract
Novel genotypes evolve under selection through mutations in pre-existing genes. However, mutations have pleiotropic phenotypic effects that influence the fitness of emerging genotypes in complex ways. The evolution of antimicrobial resistance is mediated by selection of mutations in genes coding for antibiotic-target proteins. Drug-resistance is commonly associated with a fitness cost due to the impact of resistance-conferring mutations on protein function and/or stability. These costs are expected to prohibit the selection of drug-resistant mutations at low drug pressures. Using laboratory evolution of rifampicin resistance in Escherichia coli, we show that when exposed intermittently to low concentration (0.1 × minimal inhibitory concentration) of rifampicin, the evolution of canonical drug resistance was indeed unfavorable. Instead, these bacterial populations adapted by evolving into small-colony variants that displayed enhanced pellicle-forming ability. This shift in lifestyle from planktonic to pellicle-like was necessary for enhanced fitness at low drug pressures, and was mediated by the genetic activation of the fim operon promoter, which allowed expression of type I fimbriae. Upon continued low drug exposure, these bacteria evolved exclusively into high-level drug-resistant strains through mutations at a limited set of loci within the rifampicin-resistance determining region of the rpoB gene. We show that our results are explained by mutation-specific epistasis, resulting in differential impact of lifestyle switching on the competitive fitness of different rpoB mutations. Thus, lifestyle-alterations that are selected at low selection pressures have the potential to modify the fitness effects of mutations, change the genetic structure, and affect the ultimate fate of evolving populations.
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Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage. mBio 2018; 9:mBio.01462-18. [PMID: 30131362 PMCID: PMC6106082 DOI: 10.1128/mbio.01462-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Curli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenic Escherichia coli (UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purine de novo biosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to as rcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation of purF (the first gene in the purine biosynthesis pathway) and rcpA also led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis. Uropathogenic Escherichia coli (UPEC) strains are the most common cause of urinary tract infection, a disease increasingly associated with escalating antibiotic resistance. UPEC strains possess multiple surface-associated factors that enable their colonization of the urinary tract, including fimbriae, curli, and autotransporters. Curli are extracellular amyloid fibers that enhance UPEC virulence and promote biofilm formation. Here we examined the function and regulation of curli in a UPEC pyelonephritis strain belonging to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. Curli expression at human physiological temperature led to increased biofilm formation, resistance of sessile cells to the human cationic peptide LL-37, and enhanced bladder colonization. Using a comprehensive genetic screen, we identified multiple genes involved in curli production, including several that were novel or poorly characterized with respect to curli synthesis. In total, this study demonstrates an important role for curli as a UPEC virulence factor that promotes biofilm formation, resistance, and pathogenesis.
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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26
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Research progress in urinary tract infection and its therapeutic drugs. INFECTION INTERNATIONAL 2018. [DOI: 10.2478/ii-2018-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractObjectiveThe objective of this study was to understand the pathological mechanism and therapeutic progress in the study of urinary tract infections to provide references for clinical diagnosis and identification and development of therapeutic drugs.MethodsWe summarized the types, pathological mechanisms, and therapeutic drugs for urinary tract infections on the basis of recent publications on these infections, both domestic and abroad.Results and conclusionsUrinary tract infection is mainly caused by pathogenic bacterial infection and treated by targeting bacterial adhesion, bacterial toxin, protease, urease, and siderophores, as well as using pili as vaccines and small-molecule drugs. Vaccines that target bacterial adhesion can block well the interaction between pathogens and the body, thereby reducing the incidence of urinary tract infections. The clinical efficacy of vaccines targeting bacterial toxins and proteases needs further evaluation. Vaccines targeting iron carriers retard disease progression and attenuate bacterial colonization. Urease-targeted small-molecule drugs exhibit certain curative effects and serious side effects. Small pili-targeted drugs can prevent and treat urinary tract infections by blocking the colonization and invasion of pathogens in animal models of urinary tract infections on the bladder. Adhesive FimH antibodies have entered Phase I clinical trials. However, pilicides, mannosides, and vaccines that target pili, iron carriers, and other virulence factors are still in the experimental or preclinical stages of research.
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27
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Nickerson KP, Faherty CS. Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification. J Vis Exp 2018. [PMID: 29781989 DOI: 10.3791/57322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Biofilm formation is a dynamic, multistage process that occurs in bacteria under harsh environmental conditions or times of stress. For enteric pathogens, a significant stress response is induced during gastrointestinal transit and upon bile exposure, a normal component of human digestion. To overcome the bactericidal effects of bile, many enteric pathogens form a biofilm hypothesized to permit survival when transiting through the small intestine. Here we present methodologies to define biofilm formation through solid-phase adherence assays as well as extracellular polymeric substance (EPS) matrix detection and visualization. Furthermore, biofilm dispersion assessment is presented to mimic the analysis of events triggering release of bacteria during the infection process. Crystal violet staining is used to detect adherent bacteria in a high-throughput 96-well plate adherence assay. EPS production assessment is determined by two assays, namely microscopy staining of the EPS matrix and semi-quantitative analysis with a fluorescently-conjugated polysaccharide binding lectin. Finally, biofilm dispersion is measured through colony counts and plating. Positive data from multiple assays support the characterization of biofilms and can be utilized to identify bile salt-induced biofilm formation in other bacterial strains.
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Affiliation(s)
- Kourtney P Nickerson
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital; Department of Pediatrics, Harvard Medical School
| | - Christina S Faherty
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital; Department of Pediatrics, Harvard Medical School;
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28
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Purification of Intracellular Bacterial Communities during Experimental Urinary Tract Infection Reveals an Abundant and Viable Bacterial Reservoir. Infect Immun 2018; 86:IAI.00740-17. [PMID: 29378794 DOI: 10.1128/iai.00740-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/22/2018] [Indexed: 12/17/2022] Open
Abstract
Urinary tract infections (UTIs) are a major infection of humans, particularly affecting women. Recurrent UTIs can cause significant discomfort and expose patients to high levels of antibiotic use, which in turn contributes to the development of higher antibiotic resistance rates. Most UTIs are caused by uropathogenic Escherichia coli, which is able to form intracellular collections (termed intracellular bacterial communities [IBCs]) within the epithelial cells lining the bladder lumen. IBCs are seen in both infected mice and humans and are a potential cause of recurrent UTI. Genetic and molecular studies of IBCs have been hampered both by the low number of bacteria in IBCs relative to the number extracellular bacteria and by population bottlenecks that occur during IBC formation. We now report the development of a simple and rapid technique for isolating pure IBCs from experimentally infected mice. We verified the specificity and purity of the isolated IBCs via microscopy, gene expression, and culture-based methods. Our results further demonstrated that our isolation technique practically enables specific molecular studies of IBCs. In the first such direct measurement, we determined that a single epithelial cell containing an early IBC typically contains 103 viable bacteria. Our isolation technique complements recent progress in low-input, single-cell genomics to enable future genomic studies of the formation of IBCs and their activation pathways during recurrent UTI, which may lead to novel strategies to eliminate them from the bladder.
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29
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Steiner BD, Eberly AR, Hurst MN, Zhang EW, Green HD, Behr S, Jung K, Hadjifrangiskou M. Evidence of Cross-Regulation in Two Closely Related Pyruvate-Sensing Systems in Uropathogenic Escherichia coli. J Membr Biol 2018; 251:65-74. [PMID: 29374286 DOI: 10.1007/s00232-018-0014-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 11/08/2017] [Indexed: 11/27/2022]
Abstract
Two-component systems (TCSs) dictate many bacterial responses to environmental change via the activation of a membrane-embedded sensor kinase, which has molecular specificity for a cognate response regulator protein. However, although the majority of TCSs operate through seemingly strict cognate protein-protein interactions, there have been several reports of TCSs that violate this classical model of signal transduction. Our group has recently demonstrated that some of these cross-interacting TCSs function in a manner that imparts a fitness advantage to bacterial pathogens. In this study, we describe interconnectivity between the metabolite-sensing TCSs YpdA/YpdB and BtsS/BtsR in uropathogenic Escherichia coli (UPEC). The YpdA/YpdB and BtsS/BtsR TCSs have been previously reported to interact in K12 E. coli, where they alter the expression of putative transporter genes yhjX and yjiY, respectively. These target genes are both upregulated in UPEC during acute and chronic murine models of urinary tract infection, as well as in response to pyruvate and serine added to growth media in vitro. Here, we show that proper regulation of yhjX in UPEC requires the presence of all components from both of these TCSs. By utilizing plasmid-encoded luciferase reporters tracking the activity of the yhjX and yjiY promoters, we demonstrate that deletions in one TCS substantially alter transcriptional activity of the opposing system's target gene. However, unlike in K12 E. coli, single gene deletions in the YpdA/YpdB system do not alter yjiY gene expression in UPEC, suggesting that niche and lifestyle-specific pressures may be selecting for differential cross-regulation of TCSs in pathogenic and non-pathogenic E. coli.
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Affiliation(s)
- Bradley D Steiner
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Allison R Eberly
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, 1161 21st Avenue South, MCN A5225A, Nashville, TN, 37232, USA
| | - Melanie N Hurst
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, 1161 21st Avenue South, MCN A5225A, Nashville, TN, 37232, USA
| | - Ellisa W Zhang
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, 1161 21st Avenue South, MCN A5225A, Nashville, TN, 37232, USA
| | | | - Stefan Behr
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
- Roche Diagnostics GmbH, Nonnenwald 2, 82377, Penzberg, Germany
| | - Kirsten Jung
- Munich Center for Integrated Protein Science (CIPSM) at the Department of Microbiology, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Maria Hadjifrangiskou
- Division of Molecular Pathogenesis, Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, 1161 21st Avenue South, MCN A5225A, Nashville, TN, 37232, USA.
- Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Institute for Infection, Immunology & Inflammation, Nashville, TN, USA.
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The Production of Curli Amyloid Fibers Is Deeply Integrated into the Biology of Escherichia coli. Biomolecules 2017; 7:biom7040075. [PMID: 29088115 PMCID: PMC5745457 DOI: 10.3390/biom7040075] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/13/2017] [Accepted: 10/23/2017] [Indexed: 12/29/2022] Open
Abstract
Curli amyloid fibers are the major protein component of the extracellular matrix produced by Enterobacteriaceae during biofilm formation. Curli are required for proper biofilm development and environmental persistence by Escherichia coli. Here, we present a complete and vetted genetic analysis of functional amyloid fiber biogenesis. The Keio collection of single gene deletions was screened on Congo red indicator plates to identify E. coli mutants that had defective amyloid production. We discovered that more than three hundred gene products modulated curli production. These genes were involved in fundamental cellular processes such as regulation, environmental sensing, respiration, metabolism, cell envelope biogenesis, transport, and protein turnover. The alternative sigma factors, σS and σE, had opposing roles in curli production. Mutations that induced the σE or Cpx stress response systems had reduced curli production, while mutant strains with increased σS levels had increased curli production. Mutations in metabolic pathways, including gluconeogenesis and the biosynthesis of lipopolysaccharide (LPS), produced less curli. Regulation of the master biofilm regulator, CsgD, was diverse, and the screen revealed several proteins and small RNAs (sRNA) that regulate csgD messenger RNA (mRNA) levels. Using previously published studies, we found minimal overlap between the genes affecting curli biogenesis and genes known to impact swimming or swarming motility, underlying the distinction between motile and sessile lifestyles. Collectively, the diversity and number of elements required suggest curli production is part of a highly regulated and complex developmental pathway in E. coli.
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Biofilm Formation by Uropathogenic Escherichia coli Is Favored under Oxygen Conditions That Mimic the Bladder Environment. Int J Mol Sci 2017; 18:ijms18102077. [PMID: 28973965 PMCID: PMC5666759 DOI: 10.3390/ijms18102077] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 02/06/2023] Open
Abstract
One of the most common urologic problems afflicting millions of people worldwide is urinary tract infection (UTI). The severity of UTIs ranges from asymptomatic bacteriuria to acute cystitis, and in severe cases, pyelonephritis and urosepsis. The primary cause of UTIs is uropathogenic Escherichia coli (UPEC), for which current antibiotic therapies often fail. UPEC forms multicellular communities known as biofilms on urinary catheters, as well as on and within bladder epithelial cells. Biofilm formation protects UPEC from environmental conditions, antimicrobial therapy, and the host immune system. Previous studies have investigated UPEC biofilm formation in aerobic conditions (21% oxygen); however, urine oxygen tension is reduced (4–6%), and urine contains molecules that can be used by UPEC as alternative terminal electron acceptors (ATEAs) for respiration. This study was designed to determine whether these different terminal electron acceptors utilized by E. coli influence biofilm formation. A panel of 50 urine-associated E. coli isolates was tested for the ability to form biofilm under anaerobic conditions and in the presence of ATEAs. Biofilm production was reduced under all tested sub-atmospheric levels of oxygen, with the notable exception of 4% oxygen, the reported concentration of oxygen within the bladder.
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Haque MM, Oliver MMH, Nahar K, Alam MZ, Hirata H, Tsuyumu S. CytR Homolog of Pectobacterium carotovorum subsp. carotovorum Controls Air-Liquid Biofilm Formation by Regulating Multiple Genes Involved in Cellulose Production, c-di-GMP Signaling, Motility, and Type III Secretion System in Response to Nutritional and Environmental Signals. Front Microbiol 2017; 8:972. [PMID: 28620360 PMCID: PMC5449439 DOI: 10.3389/fmicb.2017.00972] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/15/2017] [Indexed: 01/22/2023] Open
Abstract
Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King’s B at 27°C after 72 h incubation in static condition. The wild type also produced significantly higher quantities of AL biofilm on SOBGMg– (magnesium deprived) containing Cupper (Cu2+), Zinc (Zn2+), Manganese (Mn2+), Magnesium (Mg2+), and Calcium (Ca2+) compared to the ΔcytR mutant. Moreover, the wild type was produced higher amounts of biofilms compared to the mutant while responding to pH and osmotic stresses. The ΔfliC (encoding flagellin), flhD::Tn5 (encoding a master regulator) and ΔmotA (a membrane protein essential for flagellar rotation) mutants produced a lighter and more fragile AL biofilm on SOBG compared to their wild counterpart. All these mutants resulted in having weak bonds with the cellulose specific dye (Calcofluor) producing lower quantities of cellulose compared to the wild type. Gene expression analysis using mRNA collected from the AL biofilms showed that ΔcytR mutant significantly (P < 0.001) reduced the expressions of multiple genes responsible for cellulose production (bcsA, bcsE, and adrA), motility (flhD, fliA, fliC, and motA) and type III secretion system (hrpX, hrpL, hrpA, and hrpN) compared to the wild type. The CytR homolog was therefore, argued to be able to regulate the AL biofilm formation by controlling cellulose production, motility and T3SS in Pcc PC1. In addition, all the mutants exhibited poorer attachment to radish sprouts and AL biofilm cells of the wild type was resistant than stationary-phase and planktonic cells to acidity and oxidative stress compared to the same cells of the ΔcytR mutant. The results of this study therefore suggest that CytR homolog is a major determinant of Pcc PC1’s virulence, attachment and its survival mechanism.
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Affiliation(s)
- M M Haque
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur, Bangladesh
| | - M M H Oliver
- Department of Agricultural Engineering, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur, Bangladesh
| | - Kamrun Nahar
- Plant Breeding Division, Bangladesh Agricultural Research InstituteGazipur, Bangladesh
| | - Mohammad Z Alam
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur, Bangladesh
| | - Hisae Hirata
- Faculty of Agriculture, Shizuoka UniversityShizuoka, Japan
| | - Shinji Tsuyumu
- Faculty of Agriculture, Shizuoka UniversityShizuoka, Japan
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Novel genes associated with enhanced motility of Escherichia coli ST131. PLoS One 2017; 12:e0176290. [PMID: 28489862 PMCID: PMC5425062 DOI: 10.1371/journal.pone.0176290] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 04/07/2017] [Indexed: 12/20/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the cause of ~75% of all urinary tract infections (UTIs) and is increasingly associated with multidrug resistance. This includes UPEC strains from the recently emerged and globally disseminated sequence type 131 (ST131), which is now the dominant fluoroquinolone-resistant UPEC clone worldwide. Most ST131 strains are motile and produce H4-type flagella. Here, we applied a combination of saturated Tn5 mutagenesis and transposon directed insertion site sequencing (TraDIS) as a high throughput genetic screen and identified 30 genes associated with enhanced motility of the reference ST131 strain EC958. This included 12 genes that repress motility of E. coli K-12, four of which (lrhA, ihfA, ydiV, lrp) were confirmed in EC958. Other genes represented novel factors that impact motility, and we focused our investigation on characterisation of the mprA, hemK and yjeA genes. Mutation of each of these genes in EC958 led to increased transcription of flagellar genes (flhD and fliC), increased expression of the FliC flagellin, enhanced flagella synthesis and a hyper-motile phenotype. Complementation restored all of these properties to wild-type level. We also identified Tn5 insertions in several intergenic regions (IGRs) on the EC958 chromosome that were associated with enhanced motility; this included flhDC and EC958_1546. In both of these cases, the Tn5 insertions were associated with increased transcription of the downstream gene(s), which resulted in enhanced motility. The EC958_1546 gene encodes a phage protein with similarity to esterase/deacetylase enzymes involved in the hydrolysis of sialic acid derivatives found in human mucus. We showed that over-expression of EC958_1546 led to enhanced motility of EC958 as well as the UPEC strains CFT073 and UTI89, demonstrating its activity affects the motility of different UPEC strains. Overall, this study has identified and characterised a number of novel factors associated with enhanced UPEC motility.
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Kjelstrup CK, Barber AE, Norton JP, Mulvey MA, L'Abée-Lund TM. Escherichia coli O78 isolated from septicemic lambs shows high pathogenicity in a zebrafish model. Vet Res 2017; 48:3. [PMID: 28122589 PMCID: PMC5264452 DOI: 10.1186/s13567-016-0407-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 12/07/2016] [Indexed: 12/03/2022] Open
Abstract
The pathogenicity of Escherichia coli O78 strain K46, originally isolated from an outbreak of septicemia in neonatal lambs, was investigated in zebrafish embryo and murine models of infection. Its biofilm potential, cellulose production, and the expression of type 1 pili and curli fimbriae were measured by in vitro assays. The strain was highly pathogenic in the zebrafish embryo model of infection, where it killed all embryos within 24 h post inoculation (hpi) at doses as low as 1000 colony forming units. Zebrafish embryos inoculated with similar doses of commensal E. coli strains showed no signs of disease, and cleared the bacteria within 24 h. E. coli K46 colonized the murine gut at the same level as the uropathogenic E. coli (UPEC) reference strain CFT073 in CBA/J mice after oral inoculation, but infected the murine bladder significantly less than CFT073 after transurethral inoculation. Type 1 pili were clearly expressed by E. coli K46, while curli fimbriae and cellulose production were weakly expressed. The ability to produce biofilm varied in different growth media, but overall E. coli K46 was a poorer biofilm producer compared to the reference strain E. coli UTI89. In conclusion, the zebrafish lethality model provides further evidence that E. coli K46 is highly pathogenic and might be useful in future studies to identify bacterial virulence factors.
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Affiliation(s)
- Cecilie K Kjelstrup
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 8146 Dep, 0033, Oslo, Norway
| | - Amelia E Barber
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, UT, USA
| | - J Paul Norton
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, UT, USA
| | - Matthew A Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, UT, USA
| | - Trine M L'Abée-Lund
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, P.O. Box 8146 Dep, 0033, Oslo, Norway.
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Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli. Infect Immun 2016; 85:IAI.00471-16. [PMID: 27795353 DOI: 10.1128/iai.00471-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/10/2016] [Indexed: 02/05/2023] Open
Abstract
The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement.
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McLellan LK, Hunstad DA. Urinary Tract Infection: Pathogenesis and Outlook. Trends Mol Med 2016; 22:946-957. [PMID: 27692880 DOI: 10.1016/j.molmed.2016.09.003] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 09/10/2016] [Indexed: 02/07/2023]
Abstract
The clinical syndromes comprising urinary tract infection (UTI) continue to exert significant impact on millions of patients worldwide, most of whom are otherwise healthy women. Antibiotic therapy for acute cystitis does not prevent recurrences, which plague up to one fourth of women after an initial UTI. Rising antimicrobial resistance among uropathogenic bacteria further complicates therapeutic decisions, necessitating new approaches based on fundamental biological investigation. In this review, we highlight contemporary advances in the field of UTI pathogenesis and how these might inform both our clinical perspective and future scientific priorities.
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Affiliation(s)
- Lisa K McLellan
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - David A Hunstad
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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The UbiI (VisC) Aerobic Ubiquinone Synthase Is Required for Expression of Type 1 Pili, Biofilm Formation, and Pathogenesis in Uropathogenic Escherichia coli. J Bacteriol 2016; 198:2662-72. [PMID: 27161114 DOI: 10.1128/jb.00030-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/04/2016] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED Uropathogenic Escherichia coli (UPEC), which causes the majority of urinary tract infections (UTI), uses pilus-mediated adherence to initiate biofilm formation in the urinary tract. Oxygen gradients within E. coli biofilms regulate expression and localization of adhesive type 1 pili. A transposon mutant screen for strains defective in biofilm formation identified the ubiI (formerly visC) aerobic ubiquinone synthase gene as critical for UPEC biofilm formation. In this study, we characterized a nonpolar ubiI deletion mutant and compared its behavior to that of wild-type bacteria grown under aerobic and anoxic conditions. Consistent with its function as an aerobic ubiquinone-8 synthase, deletion of ubiI in UPEC resulted in reduced membrane potential, diminished motility, and reduced expression of chaperone-usher pathway pili. Loss of aerobic respiration was previously shown to negatively impact expression of type 1 pili. To determine whether this reduction in type 1 pili was due to an energy deficit, wild-type UPEC and the ubiI mutant were compared for energy-dependent phenotypes under anoxic conditions, in which quinone synthesis is undertaken by anaerobic quinone synthases. Under anoxic conditions, the two strains exhibited wild-type levels of motility but produced diminished numbers of type 1 pili, suggesting that the reduction of type 1 pilus expression in the absence of oxygen is not due to a cellular energy deficit. Acute- and chronic-infection studies in a mouse model of UTI revealed a significant virulence deficit in the ubiI mutant, indicating that UPEC encounters enough oxygen in the bladder to induce aerobic ubiquinone synthesis during infection. IMPORTANCE The majority of urinary tract infections are caused by uropathogenic E. coli, a bacterium that can respire in the presence and absence of oxygen. The bladder environment is hypoxic, with oxygen concentrations ranging from 4% to 7%, compared to 21% atmospheric oxygen. This work provides evidence that aerobic ubiquinone synthesis must be engaged during bladder infection, indicating that UPEC bacteria sense and use oxygen as a terminal electron acceptor in the bladder and that this ability drives infection potential despite the fact that UPEC is a facultative anaerobe.
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38
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Abstract
Vibrio parahaemolyticus is the most common cause of seafood-borne gastroenteritis worldwide and a blight on global aquaculture. This organism requires a horizontally acquired type III secretion system (T3SS2) to infect the small intestine, but knowledge of additional factors that underlie V. parahaemolyticus pathogenicity is limited. We used transposon-insertion sequencing to screen for genes that contribute to viability of V. parahaemolyticus in vitro and in the mammalian intestine. Our analysis enumerated and controlled for the host infection bottleneck, enabling robust assessment of genetic contributions to in vivo fitness. We identified genes that contribute to V. parahaemolyticus colonization of the intestine independent of known virulence mechanisms in addition to uncharacterized components of T3SS2. Our study revealed that toxR, an ancestral locus in Vibrio species, is required for V. parahaemolyticus fitness in vivo and for induction of T3SS2 gene expression. The regulatory mechanism by which V. parahaemolyticus ToxR activates expression of T3SS2 resembles Vibrio cholerae ToxR regulation of distinct virulence elements acquired via lateral gene transfer. Thus, disparate horizontally acquired virulence systems have been placed under the control of this ancestral transcription factor across independently evolved human pathogens.
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Abstract
Escherichia coli is one of the world's best-characterized organisms, because it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere: in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix (ECM), primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces and resistance to desiccation, the host immune system, and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this article, which concludes with insights into the future of E. coli biofilm research and potential therapies.
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40
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Metabolic Requirements of Escherichia coli in Intracellular Bacterial Communities during Urinary Tract Infection Pathogenesis. mBio 2016; 7:e00104-16. [PMID: 27073089 PMCID: PMC4959519 DOI: 10.1128/mbio.00104-16] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the primary etiological agent of over 85% of community-acquired urinary tract infections (UTIs). Mouse models of infection have shown that UPEC can invade bladder epithelial cells in a type 1 pilus-dependent mechanism, avoid a TLR4-mediated exocytic process, and escape into the host cell cytoplasm. The internalized UPEC can clonally replicate into biofilm-like intracellular bacterial communities (IBCs) of thousands of bacteria while avoiding many host clearance mechanisms. Importantly, IBCs have been documented in urine from women and children suffering acute UTI. To understand this protected bacterial niche, we elucidated the transcriptional profile of bacteria within IBCs using microarrays. We delineated the upregulation within the IBC of genes involved in iron acquisition, metabolism, and transport. Interestingly, lacZ was highly upregulated, suggesting that bacteria were sensing and/or utilizing a galactoside for metabolism in the IBC. A ΔlacZ strain displayed significantly smaller IBCs than the wild-type strain and was attenuated during competitive infection with a wild-type strain. Similarly, a galK mutant resulted in smaller IBCs and attenuated infection. Further, analysis of the highly upregulated gene yeaR revealed that this gene contributes to oxidative stress resistance and type 1 pilus production. These results suggest that bacteria within the IBC are under oxidative stress and, consistent with previous reports, utilize nonglucose carbon metabolites. Better understanding of the bacterial mechanisms used for IBC development and establishment of infection may give insights into development of novel anti-virulence strategies. Urinary tract infections (UTIs) are one of the most common bacterial infections, impacting mostly women. Every year, millions of UTIs occur in the U.S. with most being caused by uropathogenic E. coli (UPEC). During a UTI, UPEC invade bladder cells and form an intracellular bacterial community (IBC) that allows for the bacteria to replicate protected from the host immune response. In this study, we investigated genes that are expressed by UPEC within the IBC and determined how they contribute to the formation of this specialized community. Our findings suggest that galactose is important for UPEC growth in the IBC. Additionally, we found that a gene involved in oxidative stress is also important in the regulation of a key factor needed for UPEC invasion of bladder cells. These results may open the door for the development of treatments to diminish UTI frequency and/or severity.
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41
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Zhang H, Susanto TT, Wan Y, Chen SL. Comprehensive mutagenesis of the fimS promoter regulatory switch reveals novel regulation of type 1 pili in uropathogenic Escherichia coli. Proc Natl Acad Sci U S A 2016; 113:4182-7. [PMID: 27035967 PMCID: PMC4839427 DOI: 10.1073/pnas.1522958113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Type 1 pili (T1P) are major virulence factors for uropathogenic Escherichia coli (UPEC), which cause both acute and recurrent urinary tract infections. T1P expression therefore is of direct relevance for disease. T1P are phase variable (both piliated and nonpiliated bacteria exist in a clonal population) and are controlled by an invertible DNA switch (fimS), which contains the promoter for the fim operon encoding T1P. Inversion of fimS is stochastic but may be biased by environmental conditions and other signals that ultimately converge at fimS itself. Previous studies of fimS sequences important for T1P phase variation have focused on laboratory-adapted E coli strains and have been limited in the number of mutations or by alteration of the fimS genomic context. We surmounted these limitations by using saturating genomic mutagenesis of fimS coupled with accurate sequencing to detect both mutations and phase status simultaneously. In addition to the sequences known to be important for biasing fimS inversion, our method also identifies a previously unknown pair of 5' UTR inverted repeats that act by altering the relative fimA levels to control phase variation. Thus we have uncovered an additional layer of T1P regulation potentially impacting virulence and the coordinate expression of multiple pilus systems.
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Affiliation(s)
- Huibin Zhang
- Infectious Diseases Group, Genome Institute of Singapore, Singapore 138672
| | - Teodorus T Susanto
- Stem Cell and Development, Genome Institute of Singapore, Singapore 138672
| | - Yue Wan
- Stem Cell and Development, Genome Institute of Singapore, Singapore 138672
| | - Swaine L Chen
- Infectious Diseases Group, Genome Institute of Singapore, Singapore 138672; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074
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Strengths and Limitations of Model Systems for the Study of Urinary Tract Infections and Related Pathologies. Microbiol Mol Biol Rev 2016; 80:351-67. [PMID: 26935136 DOI: 10.1128/mmbr.00067-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Urinary tract infections (UTIs) are some of the most common bacterial infections worldwide and are a source of substantial morbidity among otherwise healthy women. UTIs can be caused by a variety of microbes, but the predominant etiologic agent of these infections is uropathogenic Escherichia coli (UPEC). An especially troubling feature of UPEC-associated UTIs is their high rate of recurrence. This problem is compounded by the drastic increase in the global incidence of antibiotic-resistant UPEC strains over the past 15 years. The need for more-effective treatments for UTIs is driving research aimed at bettering our understanding of the virulence mechanisms and host-pathogen interactions that occur during the course of these infections. Surrogate models of human infection, including cell culture systems and the use of murine, porcine, avian, teleost (zebrafish), and nematode hosts, are being employed to define host and bacterial factors that modulate the pathogenesis of UTIs. These model systems are revealing how UPEC strains can avoid or overcome host defenses and acquire scarce nutrients while also providing insight into the virulence mechanisms used by UPEC within compromised individuals, such as catheterized patients. Here, we summarize our current understanding of UTI pathogenesis while also giving an overview of the model systems used to study the initiation, persistence, and recurrence of UTIs and life-threatening sequelae like urosepsis. Although we focus on UPEC, the experimental systems described here can also provide valuable insight into the disease processes associated with other bacterial pathogens both within the urinary tract and elsewhere within the host.
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Silva-Valenzuela CA, Molina-Quiroz RC, Desai P, Valenzuela C, Porwollik S, Zhao M, Hoffman RM, Andrews-Polymenis H, Contreras I, Santiviago CA, McClelland M. Analysis of Two Complementary Single-Gene Deletion Mutant Libraries of Salmonella Typhimurium in Intraperitoneal Infection of BALB/c Mice. Front Microbiol 2016; 6:1455. [PMID: 26779130 PMCID: PMC4700939 DOI: 10.3389/fmicb.2015.01455] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/04/2015] [Indexed: 01/20/2023] Open
Abstract
Two pools of individual single gene deletion (SGD) mutants of S. Typhimurium 14028s encompassing deletions of 3,923 annotated non-essential ORFs and sRNAs were screened by intraperitoneal (IP) injection in BALB/c mice followed by recovery from spleen and liver 2 days post infection. The relative abundance of each mutant was measured by microarray hybridization. The two mutant libraries differed in the orientation of the antibiotic resistance cassettes (either sense-oriented KanR, SGD-K, or antisense-oriented CamR, SGD-C). Consistent systemic colonization defects were observed in both libraries and both organs for hundreds of mutants of genes previously reported to be important after IP injection in this animal model, and for about 100 new candidate genes required for systemic colonization. Four mutants with a range of apparent fitness defects were confirmed using competitive infections with the wild-type parental strain: ΔSTM0286, ΔSTM0551, ΔSTM2363, and ΔSTM3356. Two mutants, ΔSTM0286 and ΔSTM2363, were then complemented in trans with a plasmid encoding an intact copy of the corresponding wild-type gene, and regained the ability to fully colonize BALB/c mice systemically. These results suggest the presence of many more undiscovered Salmonella genes with phenotypes in IP infection of BALB/c mice, and validate the libraries for application to other systems.
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Affiliation(s)
- Cecilia A Silva-Valenzuela
- Department of Microbiology and Molecular Genetics, University of California, IrvineIrvine, CA, USA; Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de ChileSantiago, Chile
| | - Roberto C Molina-Quiroz
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de ChileSantiago, Chile; Center for Adaptation Genetics and Drug Resistance, Tufts UniversityBoston, MA, USA
| | - Prerak Desai
- Department of Microbiology and Molecular Genetics, University of California, Irvine Irvine, CA, USA
| | - Camila Valenzuela
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile Santiago, Chile
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California, Irvine Irvine, CA, USA
| | | | - Robert M Hoffman
- Anticancer Inc.San Diego, CA, USA; Department of Surgery, UC San Diego School of Medicine, University of California, San DiegoSan Diego, CA, USA
| | - Helene Andrews-Polymenis
- Department of Microbial Pathogenesis and Immunology, Texas A&M University College Station, TX, USA
| | - Inés Contreras
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile Santiago, Chile
| | - Carlos A Santiviago
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile Santiago, Chile
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine Irvine, CA, USA
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Kakkanat A, Totsika M, Schaale K, Duell BL, Lo AW, Phan MD, Moriel DG, Beatson SA, Sweet MJ, Ulett GC, Schembri MA. The role of H4 flagella in Escherichia coli ST131 virulence. Sci Rep 2015; 5:16149. [PMID: 26548325 PMCID: PMC4637896 DOI: 10.1038/srep16149] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/02/2015] [Indexed: 01/04/2023] Open
Abstract
Escherichia coli sequence type 131 (ST131) is a globally dominant multidrug resistant clone associated with urinary tract and bloodstream infections. Most ST131 strains exhibit resistance to multiple antibiotics and cause infections associated with limited treatment options. The largest sub-clonal ST131 lineage is resistant to fluoroquinolones, contains the type 1 fimbriae fimH30 allele and expresses an H4 flagella antigen. Flagella are motility organelles that contribute to UPEC colonisation of the upper urinary tract. In this study, we examined the specific role of H4 flagella in ST131 motility and interaction with host epithelial and immune cells. We show that the majority of H4-positive ST131 strains are motile and are enriched for flagella expression during static pellicle growth. We also tested the role of H4 flagella in ST131 through the construction of specific mutants, over-expression strains and isogenic mutants that expressed alternative H1 and H7 flagellar subtypes. Overall, our results revealed that H4, H1 and H7 flagella possess conserved phenotypes with regards to motility, epithelial cell adhesion, invasion and uptake by macrophages. In contrast, H4 flagella trigger enhanced induction of the anti-inflammatory cytokine IL-10 compared to H1 and H7 flagella, a property that may contribute to ST131 fitness in the urinary tract.
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Affiliation(s)
- Asha Kakkanat
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Makrina Totsika
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kolja Schaale
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Benjamin L Duell
- School of Medical Science, and Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia
| | - Alvin W Lo
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Danilo G Moriel
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
| | - Matthew J Sweet
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia.,Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Glen C Ulett
- School of Medical Science, and Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia.,Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, Australia
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45
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Maher MC, Lim JY, Gunawan C, Cegelski L. Cell-Based High-Throughput Screening Identifies Rifapentine as an Inhibitor of Amyloid and Biofilm Formation in Escherichia coli. ACS Infect Dis 2015; 1:460-8. [PMID: 27623312 DOI: 10.1021/acsinfecdis.5b00055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Escherichia coli assemble functional amyloid fibers termed curli that contribute to bacterial adhesion, biofilm formation, and host pathogenesis. We developed a cell-based high-throughput screen to identify inhibitors of curli-mediated adhesion in the laboratory strain MC4100 and curli-associated biofilm formation in the uropathogenic E. coli clinical isolate UTI89. Inhibitors of biofilm formation can operate through many mechanisms, and such inhibitors could hold therapeutic value in preventing and treating urinary tract infections. The curli-specific screen allows the identification of compounds that inhibit either curli expression, curli biogenesis, or adhesion by normally produced curli. In screening the NIH Clinical Collection of 446 compounds, we identified rifapentine as a potent inhibitor in both of these screens. Rifapentine is an antibiotic used to treat tuberculosis that targets RNA polymerase, but prevents curli-dependent adhesion and biofilm formation in E. coli at concentrations below those that affect viability. Rifapentine inhibits curli production and prevents biofilm formation on plastic, on agar, and at the air-liquid interface by inhibiting curli gene transcription. Comparisons with a cephalosporin antibiotic further revealed that curli production is not affected by standard antibiotic treatment and cell killing pressure. Thus, we reveal a new role independent of killing activity for rifapentine as an inhibitor of curli and curli-mediated biofilm formation.
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Affiliation(s)
- Marie C. Maher
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ji Youn Lim
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Cheston Gunawan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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Genome modifications and cloning using a conjugally transferable recombineering system. ACTA ACUST UNITED AC 2015; 8:24-35. [PMID: 28352570 PMCID: PMC4980705 DOI: 10.1016/j.btre.2015.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/24/2015] [Accepted: 08/24/2015] [Indexed: 11/21/2022]
Abstract
The genetic modification of primary bacterial disease isolates is challenging due to the lack of highly efficient genetic tools. Herein we describe the development of a modified PCR-based, λ Red-mediated recombineering system for efficient deletion of genes in Gram-negative bacteria. A series of conjugally transferrable plasmids were constructed by cloning an oriT sequence and different antibiotic resistance genes into recombinogenic plasmid pKD46. Using this system we deleted ten different genes from the genomes of Edwardsiella ictaluri and Aeromonas hydrophila. A temperature sensitive and conjugally transferable flp recombinase plasmid was developed to generate markerless gene deletion mutants. We also developed an efficient cloning system to capture larger bacterial genetic elements and clone them into a conjugally transferrable plasmid for facile transferring to Gram-negative bacteria. This system should be applicable in diverse Gram-negative bacteria to modify and complement genomic elements in bacteria that cannot be manipulated using available genetic tools.
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Subashchandrabose S, Mobley HLT. Virulence and Fitness Determinants of Uropathogenic Escherichia coli. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0015-2012. [PMID: 26350328 PMCID: PMC4566162 DOI: 10.1128/microbiolspec.uti-0015-2012] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Indexed: 01/10/2023] Open
Abstract
Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a major global public health concern. Increasing antibiotic resistance found in clinical UPEC isolates underscores the immediate need for development of novel therapeutics against this pathogen. Better understanding of the fitness and virulence mechanisms that are integral to the pathogenesis of UTI will facilitate identification of novel strategies to prevent and treat infection with UPEC. Working towards that goal, the global UPEC research community has made great strides at unraveling various virulence and fitness genes. Here, we summarize major findings on virulence and fitness determinants that enable UPEC to successfully survive and colonize the urinary tract of mammalian hosts. Major sections of this chapter are devoted to the role of iron acquisition systems, metabolic pathways, fimbriae, flagella, toxins, biofilm formation, capsule, and strain-specific genes in the initiation and progression of UTIs. Transcriptomes of UPEC during experimental UTI in a murine model and naturally occurring UTI in women are compared to elucidate virulence mechanisms specifically involved in human UTI. Capitalizing on the advances in molecular pathogenesis research by translating these findings will help develop better clinical strategies for prevention and management of UTIs.
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Affiliation(s)
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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Adherent-Invasive Escherichia coli Production of Cellulose Influences Iron-Induced Bacterial Aggregation, Phagocytosis, and Induction of Colitis. Infect Immun 2015. [PMID: 26216423 DOI: 10.1128/iai.00904-15] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Adherent-invasive Escherichia coli (AIEC), a functionally distinct subset of resident intestinal E. coli associated with Crohn's disease, is characterized by enhanced epithelial adhesion and invasion, survival within macrophages, and biofilm formation. Environmental factors, such as iron, modulate E. coli production of extracellular structures, which in turn influence the formation of multicellular communities, such as biofilms, and bacterial interactions with host cells. However, the physiological and functional responses of AIEC to variable iron availability have not been thoroughly investigated. We therefore characterized the impact of iron on the physiology of AIEC strain NC101 and subsequent interactions with macrophages. Iron promoted the cellulose-dependent aggregation of NC101. Bacterial cells recovered from the aggregates were more susceptible to phagocytosis than planktonic cells, which corresponded with the decreased macrophage production of the proinflammatory cytokine interleukin-12 (IL-12) p40. Prevention of aggregate formation through the disruption of cellulose production reduced the phagocytosis of iron-exposed NC101. In contrast, under iron-limiting conditions, where NC101 aggregation is not induced, the disruption of cellulose production enhanced NC101 phagocytosis and decreased macrophage secretion of IL-12 p40. Finally, abrogation of cellulose production reduced NC101 induction of colitis when NC101 was monoassociated in inflammation-prone Il10(-/-) mice. Taken together, our results introduce cellulose as a novel physiological factor that impacts host-microbe-environment interactions and alters the proinflammatory potential of AIEC.
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49
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Hibbing ME, Conover MS, Hultgren SJ. The unexplored relationship between urinary tract infections and the autonomic nervous system. Auton Neurosci 2015; 200:29-34. [PMID: 26108548 DOI: 10.1016/j.autneu.2015.06.002] [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: 02/05/2015] [Revised: 05/14/2015] [Accepted: 06/02/2015] [Indexed: 11/30/2022]
Abstract
Urinary tract infections (UTIs), the majority of which are caused by uropathogenic E. coli (UPEC), are extremely common infections that preferentially effect women. Additional complicating factors, such as catheterization, diabetes, and spinal cord injuries can increase the frequency and severity of UTIs. The rise of antimicrobial resistant uropathogens and the ability of this disease to chronically recur make the development of alternative preventative and therapeutic modalities a priority. The major symptoms of UTIs, urgency, frequency, and dysuria, are readouts of the autonomic nervous system (ANS) and the majority of the factors that lead to complicated UTIs have been shown to impact ANS function. This review summarizes the decades' long efforts to understand the molecular mechanisms of the interactions between UPEC and the host, with a particular focus on the recent findings revealing the molecular, bacteriological, immunological and epidemiological complexity of pathogenesis. Additionally, we describe the progress that has been made in: i) generating vaccines and anti-virulence compounds that prevent and/or treat UTI by blocking bacterial adherence to urinary tract tissue and; and ii) elucidating the mechanism by which anti-inflammatories are able to alleviate symptoms and improve disease prognosis. Finally, the potential relationships between the ANS and UTI are considered throughout. While these relationships have not been experimentally explored, the known interactions between numerous UTI characteristics (symptoms, complicating factors, and inflammation) and ANS function suggest that UTIs are directly impacting ANS stimulation and that ANS (dys)function may alter UTI prognosis.
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Affiliation(s)
- Michael E Hibbing
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States; Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States.
| | - Matt S Conover
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States; Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States
| | - Scott J Hultgren
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States; Center for Women's Infectious Disease Research, Washington University School of Medicine in St. Louis, St. Louis, MO 63110-1010, United States.
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50
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Carey AJ, Tan CK, Ipe DS, Sullivan MJ, Cripps AW, Schembri MA, Ulett GC. Urinary tract infection of mice to model human disease: Practicalities, implications and limitations. Crit Rev Microbiol 2015; 42:780-99. [PMID: 26006172 DOI: 10.3109/1040841x.2015.1028885] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Murine models of human UTI are vital experimental tools that have helped to elucidate UTI pathogenesis and advance knowledge of potential treatment and infection prevention strategies. Fundamentally, several variables are inherent in different murine models, and understanding the limitations of these variables provides an opportunity to understand how models may be best applied to research aimed at mimicking human disease. In this review, we discuss variables inherent in murine UTI model studies and how these affect model usage, data analysis and data interpretation. We examine recent studies that have elucidated UTI host-pathogen interactions from the perspective of gene expression, and review new studies of biofilm and UTI preventative approaches. We also consider potential standards for variables inherent in murine UTI models and discuss how these might expand the utility of models for mimicking human disease and uncovering new aspects of pathogenesis.
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Affiliation(s)
- Alison J Carey
- a Menzies Health Institute Queensland & School of Medical Sciences, Griffith University , Gold Coast , Australia
| | - Chee K Tan
- a Menzies Health Institute Queensland & School of Medical Sciences, Griffith University , Gold Coast , Australia
| | - Deepak S Ipe
- a Menzies Health Institute Queensland & School of Medical Sciences, Griffith University , Gold Coast , Australia
| | - Matthew J Sullivan
- a Menzies Health Institute Queensland & School of Medical Sciences, Griffith University , Gold Coast , Australia
| | - Allan W Cripps
- b Menzies Health Institute Queensland, Griffith University , Gold Coast , Australia , and
| | - Mark A Schembri
- c School of Chemistry and Molecular Biosciences, University of Queensland , Brisbane , Australia
| | - Glen C Ulett
- a Menzies Health Institute Queensland & School of Medical Sciences, Griffith University , Gold Coast , Australia
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