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Nanayakkara BS, O'Brien CL, Gordon DM. Diversity and distribution of Klebsiella capsules in Escherichia coli. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:107-117. [PMID: 30411512 DOI: 10.1111/1758-2229.12710] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 10/31/2018] [Accepted: 11/03/2018] [Indexed: 06/08/2023]
Abstract
E. coli strains responsible for elevated counts (blooms) in freshwater reservoirs in Australia carry a capsule originating from Klebsiella. The occurrence of Klebsiella capsules in E. coli was about 7% overall and 23 different capsule types were detected. Capsules were observed in strains from phylogroups A, B1 and C, but were absent from phylogroup B2, D, E and F strains. In general, few A, B1 or C lineages were capsule-positive, but when a lineage was encapsulated multiple different capsule types were present. All Klebsiella capsule-positive strains were of serogroups O8, O9 and O89. Regardless of the phylogroup, O9 strains were more likely to be capsule-positive than O8 strains. Given the sequence similarity, it appears that both the capsule region and the O-antigen gene region are transferred to E. coli from Klebsiella as a single block via horizontal gene transfer events. Pan genome analysis indicated that there were only modest differences between encapsulated and non-encapsulated strains belonging to phylogroup A. The possession of a Klebsiella capsule, but not the type of capsule, is likely a key determinant of the bloom status of a strain.
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Affiliation(s)
- Buddhie S Nanayakkara
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
- Department of Botany, Faculty of Science, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Claire L O'Brien
- Medical School, The Australian National University, Canberra, ACT 2601, Australia
- Gastroenterology and Hepatology Unit, Canberra Hospital, Canberra, ACT, Australia
| | - David M Gordon
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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52
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Asadi Karam MR, Habibi M, Bouzari S. Urinary tract infection: Pathogenicity, antibiotic resistance and development of effective vaccines against Uropathogenic Escherichia coli. Mol Immunol 2019; 108:56-67. [PMID: 30784763 DOI: 10.1016/j.molimm.2019.02.007] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 02/02/2019] [Accepted: 02/12/2019] [Indexed: 12/13/2022]
Abstract
Urinary tract infections (UTIs) are recognized as one of the most common infectious diseases in the world that can be divided to different types. Uropathogenic Escherichia coli (UPEC) strains are the most prevalent causative agent of UTIs that applied different virulence factors such as fimbriae, capsule, iron scavenger receptors, flagella, toxins, and lipopolysaccharide for their pathogenicity in the urinary tract. Despite the high pathogenicity of UPEC strains, host utilizes different immune systems such as innate and adaptive immunity for eradication of them from the urinary tract. The routine therapy of UTIs is based on the use of antibiotics such as β-lactams, trimethoprim, nitrofurantoin and quinolones in many countries. Unfortunately, the widespread and misuse of these antibiotics resulted in the increasing rate of resistance to them in the societies. Increasing antibiotic resistance and their side effects on human body show the need to develop alternative strategies such as vaccine against UTIs. Developing a vaccine against UTI pathogens will have an important role in reduction the mortality rate as well as reducing economic costs. Different vaccines based on the whole cells (killed or live-attenuated vaccines) and antigens (subunits, toxins and conjugatedvaccines) have been evaluated against UTIs pathogens. Furthermore, other therapeutic strategies such as the use of probiotics and antimicrobial peptides are considered against UTIs. Despite the extensive efforts, limited success has been achieved and more studies are needed to reach an alternative of antibiotics for treatment of UTIs.
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Affiliation(s)
| | - Mehri Habibi
- Department of Molecular Biology, Pasteur Institute of Iran, Pasteur Ave., Tehran, 13164, Iran.
| | - Saeid Bouzari
- Department of Molecular Biology, Pasteur Institute of Iran, Pasteur Ave., Tehran, 13164, Iran.
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53
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Ming SA, Cottman-Thomas E, Black NC, Chen Y, Veeramachineni V, Peterson DC, Chen X, Tedaldi LM, Wagner GK, Cai C, Linhardt RJ, Vann WF. Interaction of Neisseria meningitidis Group X N-acetylglucosamine-1-phosphotransferase with its donor substrate. Glycobiology 2018; 28:100-107. [PMID: 29228283 DOI: 10.1093/glycob/cwx100] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/05/2017] [Indexed: 12/16/2022] Open
Abstract
Neisseria meningitidis Group X is an emerging cause of bacterial meningitis in Sub-Saharan Africa. The capsular polysaccharide of Group X is a homopolymer of N-acetylglucosamine α(1-4) phosphate and is a vaccine target for prevention of disease associated with this meningococcal serogroup. We have demonstrated previously that the formation of the polymer is catalyzed by a phosphotransferase which transfers N-acetylglucosamine-1-phosphate from UDP-N-acetylglucosamine to the 4-hydroxyl of the N-acetylglucosamine on the nonreducing end of the growing chain. In this study, we use substrate analogs of UDP-GlcNAc to define the enzyme/donor substrate interactions critical for catalysis. Our kinetic analysis of the phosphotransferase reaction is consistent with a sequential mechanism of substrate addition and product release. The use of novel uracil modified analogs designed by Wagner et al. enabled us to assess whether the CsxA-catalyzed reaction is consistent with a donor dependent conformational change. As expected with this model for glycosyltransferases, UDP-GlcNAc analogs with bulky uracil modifications are not substrates but are inhibitors. An analog with a smaller iodo uracil substitution is a substrate and a less potent inhibitor. Moreover, our survey of analogs with modifications on the N-acetylglucosamine residue of the sugar nucleotide donor highlights the importance of substituents at C2 and C4 of the sugar residue. The hydroxyl group at C4 and the structure of the acyl group at C2 are very important for specificity and substrate interactions during the polymerization reaction. While most analogs modified at C2 were inhibitors, acetamido analogs were also substrates suggesting the importance of the carbonyl group.
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Affiliation(s)
- Shonoi A Ming
- Laboratory of Bacterial Polysaccharides, FDA, Silver Spring, MD 20993, USA
| | | | - Natalee C Black
- Laboratory of Bacterial Polysaccharides, FDA, Silver Spring, MD 20993, USA
| | - Yi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | | | - Dwight C Peterson
- Laboratory of Bacterial Polysaccharides, FDA, Silver Spring, MD 20993, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | | | - Gerd K Wagner
- Department of Chemistry, King's College, London SE 11DB, UK
| | - Chao Cai
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Robert J Linhardt
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Willie F Vann
- Laboratory of Bacterial Polysaccharides, FDA, Silver Spring, MD 20993, USA
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54
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Harris S, Piotrowska MJ, Goldstone RJ, Qi R, Foster G, Dobrindt U, Madec JY, Valat C, Rao FV, Smith DGE. Variant O89 O-Antigen of E. coli Is Associated With Group 1 Capsule Loci and Multidrug Resistance. Front Microbiol 2018; 9:2026. [PMID: 30233517 PMCID: PMC6128206 DOI: 10.3389/fmicb.2018.02026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/09/2018] [Indexed: 11/13/2022] Open
Abstract
Bacterial surface polysaccharides play significant roles in fitness and virulence. In Gram-negative bacteria such as Escherichia coli, major surface polysaccharides are lipopolysaccharide (LPS) and capsule, representing O- and K-antigens, respectively. There are multiple combinations of O:K types, many of which are well-characterized and can be related to ecotype or pathotype. In this investigation, we have identified a novel O:K permutation resulting through a process of major genome reorganization in a clade of E. coli. A multidrug-resistant, extended-spectrum β-lactamase (ESBL)-producing strain - E. coli 26561 - represented a prototype of strains combining a locus variant of O89 and group 1 capsular polysaccharide. Specifically, the variant O89 locus in this strain was truncated at gnd, flanked by insertion sequences and located between nfsB and ybdK and we apply the term O89m for this variant. The prototype lacked colanic acid and O-antigen loci between yegH and hisI with this tandem polysaccharide locus being replaced with a group 1 capsule (G1C) which, rather than being a recognized E. coli capsule type, this locus matched to Klebsiella K10 capsule type. A genomic survey identified more than 200 E. coli strains which possessed the O89m locus variant with one of a variety of G1C types. Isolates from our collection with the combination of O89m and G1C all displayed a mucoid phenotype and E. coli 26561 was unusual in exhibiting a mucoviscous phenotype more recognized as a characteristic among Klebsiella strains. Despite the locus truncation and novel location, all O89m:G1C strains examined showed a ladder pattern typifying smooth LPS and also showed high molecular weight, alcian blue-staining polysaccharide in cellular and/or extra-cellular fractions. Expression of both O-antigen and capsule biosynthesis loci were confirmed in prototype strain 26561 through quantitative proteome analysis. Further in silico exploration of more than 200 E. coli strains possessing the O89m:G1C combination identified a very high prevalence of multidrug resistance (MDR) - 85% possessed resistance to three or more antibiotic classes and a high proportion (58%) of these carried ESBL and/or carbapenemase. The increasing isolation of O89m:G1C isolates from extra-intestinal infection sites suggests that these represents an emergent clade of invasive, MDR E. coli.
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Affiliation(s)
- Susan Harris
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Marta J Piotrowska
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | | | - Ruby Qi
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
| | - Geoffrey Foster
- Veterinary Services, SAC Consulting, Scotland's Rural College, Inverness, United Kingdom
| | - Ulrich Dobrindt
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Jean-Yves Madec
- Unité Antibiorésistances et Virulences Bactériennes, Anses Laboratoire de Lyon, Université Lyon-1, Lyon, France
| | - Charlotte Valat
- Unité Antibiorésistances et Virulences Bactériennes, Anses Laboratoire de Lyon, Université Lyon-1, Lyon, France
| | | | - David G E Smith
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
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55
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Draft Genome Sequences of Escherichia coli Strains FP2 and FP3, Isolated from the Canada Goose (Branta canadensis). Microbiol Resour Announc 2018; 7:MRA01079-18. [PMID: 30533932 PMCID: PMC6256524 DOI: 10.1128/mra.01079-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/08/2018] [Indexed: 11/20/2022] Open
Abstract
Draft genomes of two strains of Escherichia coli, FP2 and FP3, isolated from the feces of the Canada goose (Branta canadensis), were sequenced. Genome sizes were 5.26 Mb with a predicted G+C content of 50.54% (FP2) and 5.07 Mb with a predicted G+C content of 50.41% (FP3). Draft genomes of two strains of Escherichia coli, FP2 and FP3, isolated from the feces of the Canada goose (Branta canadensis), were sequenced. Genome sizes were 5.26 Mb with a predicted G+C content of 50.54% (FP2) and 5.07 Mb with a predicted G+C content of 50.41% (FP3).
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56
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Zhou C, Chia GWN, Ho JCS, Seviour T, Sailov T, Liedberg B, Kjelleberg S, Hinks J, Bazan GC. Informed Molecular Design of Conjugated Oligoelectrolytes To Increase Cell Affinity and Antimicrobial Activity. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Cheng Zhou
- School of Chemical and Biomedical Engineering Singapore
| | - Geraldine W. N. Chia
- Interdisciplinary Graduate School Singapore
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - James C. S. Ho
- Centre for Biomimetic Sensor ScienceSchool of Materials Science & EngineeringNanyang Technological University (NTU) Singapore 639798 Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Talgat Sailov
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Bo Liedberg
- Interdisciplinary Graduate School Singapore
- Centre for Biomimetic Sensor ScienceSchool of Materials Science & EngineeringNanyang Technological University (NTU) Singapore 639798 Singapore
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Guillermo C. Bazan
- School of Chemical and Biomedical Engineering Singapore
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
- Center for Polymers and Organic SolidsDepartments of Chemistry & Biochemistry and MaterialsUniversity of California, Santa Barbara Santa Barbara CA 93106 USA
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57
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Zhou C, Chia GWN, Ho JCS, Seviour T, Sailov T, Liedberg B, Kjelleberg S, Hinks J, Bazan GC. Informed Molecular Design of Conjugated Oligoelectrolytes To Increase Cell Affinity and Antimicrobial Activity. Angew Chem Int Ed Engl 2018; 57:8069-8072. [PMID: 29707869 DOI: 10.1002/anie.201803103] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/27/2018] [Indexed: 12/21/2022]
Abstract
Membrane-intercalating conjugated oligoelectrolytes (COEs) are emerging as potential alternatives to conventional, yet increasingly ineffective, antibiotics. Three readily accessible COEs, belonging to an unreported series containing a stilbene core, namely D4, D6, and D8, were designed and synthesized so that the hydrophobicity increases with increasing side-chain length. Decreased aqueous solubility correlates with increased uptake by E. coli. The minimum inhibitory concentration (MIC) of D8 is 4 μg mL-1 against both E. coli and E. faecalis, with an effective uptake of 72 %. In contrast, the MIC value of the shortest COE, D4, is 128 μg mL-1 owing to the low cellular uptake of 3 %. These findings demonstrate the application of rational design to generate efficacious antimicrobial COEs that have potential as low-cost antimicrobial agents.
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Affiliation(s)
- Cheng Zhou
- School of Chemical and Biomedical Engineering, Singapore
| | - Geraldine W N Chia
- Interdisciplinary Graduate School, Singapore.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - James C S Ho
- Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University (NTU), Singapore, 639798, Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Talgat Sailov
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Bo Liedberg
- Interdisciplinary Graduate School, Singapore.,Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University (NTU), Singapore, 639798, Singapore
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Guillermo C Bazan
- School of Chemical and Biomedical Engineering, Singapore.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore.,Center for Polymers and Organic Solids, Departments of Chemistry & Biochemistry and Materials, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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58
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Borgersen Q, Bolick DT, Kolling GL, Aijuka M, Ruiz-Perez F, Guerrant RL, Nataro JP, Santiago AE. Abundant production of exopolysaccharide by EAEC strains enhances the formation of bacterial biofilms in contaminated sprouts. Gut Microbes 2018; 9:264-278. [PMID: 29543544 PMCID: PMC6219584 DOI: 10.1080/19490976.2018.1429877] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/02/2018] [Accepted: 01/12/2018] [Indexed: 02/03/2023] Open
Abstract
Enteroaggregative E. coli (EAEC) is associated with food-borne outbreaks of diarrhea and growth faltering among children in developing countries. A Shiga toxin-producing EAEC strain of serotype O104:H4 strain caused one of the largest outbreaks of a food-borne infection in Europe in 2011. The outbreak was traced to contaminated fenugreek sprouts, yet the mechanisms whereby such persistent contamination of sprouts could have occurred are not clear. We found that under ambient conditions of temperature and in minimal media, pathogenic Shiga toxin-producing EAEC O104:H4 227-11 and non-Shiga toxin-producing 042 strains both produce high levels of exopolysaccharide structures (EPS) that are released to the external milieu. The exopolysaccharide was identified as colanic acid (CA). Unexpectedly, Shiga-toxin producing EAEC strain 227-11 produced 3-6-fold higher levels of CA than the 042 strain, suggesting differential regulation of the CA in the two strains. The presence of CA was accompanied by the formation of large biofilm structures on the surface of sprouts. The wcaF-wza chromosomal locus was required for the synthesis of CA in EAEC 042. Deletion in the glycosyltransferase wcaE gene abolished the production of CA in 042, and resulted in diminished adherence to sprouts when co-cultured at ambient temperature. In conclusion, this work suggests that copious production of CA may contribute to persistence of EAEC in the environment and suggests a potential explanation for the large Shiga toxin-producing EAEC outbreak in 2011.
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Affiliation(s)
- Quintin Borgersen
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children's Hospital, Charlottesville, Virginia
| | - David T. Bolick
- Center for Global Health, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA , USA
| | - Glynis L. Kolling
- Center for Global Health, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA , USA
| | - Matthew Aijuka
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children's Hospital, Charlottesville, Virginia
| | - Fernando Ruiz-Perez
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children's Hospital, Charlottesville, Virginia
| | - Richard L. Guerrant
- Center for Global Health, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA , USA
| | - James P. Nataro
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children's Hospital, Charlottesville, Virginia
| | - Araceli E. Santiago
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children's Hospital, Charlottesville, Virginia
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59
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Yang S, Xi D, Jing F, Kong D, Wu J, Feng L, Cao B, Wang L. Genetic diversity of K-antigen gene clusters of Escherichia coli and their molecular typing using a suspension array. Can J Microbiol 2018; 64:231-241. [PMID: 29357266 DOI: 10.1139/cjm-2017-0620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Capsular polysaccharides (CPSs), or K-antigens, are the major surface antigens of Escherichia coli. More than 80 serologically unique K-antigens are classified into 4 groups (Groups 1-4) of capsules. Groups 1 and 4 contain the Wzy-dependent polymerization pathway and the gene clusters are in the order galF to gnd; Groups 2 and 3 contain the ABC-transporter-dependent pathway and the gene clusters consist of 3 regions, regions 1, 2 and 3. Little is known about the variations among the gene clusters. In this study, 9 serotypes of K-antigen gene clusters (K2ab, K11, K20, K24, K38, K84, K92, K96, and K102) were sequenced and correlated with their CPS chemical structures. On the basis of sequence data, a K-antigen-specific suspension array that detects 10 distinct CPSs, including the above 9 CPSs plus K30, was developed. This is the first report to catalog the genetic features of E. coli K-antigen variations and to develop a suspension array for their molecular typing. The method has a number of advantages over traditional bacteriophage and serum agglutination methods and lays the foundation for straightforward identification and detection of additional K-antigens in the future.
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Affiliation(s)
- Shuang Yang
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Daoyi Xi
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Fuyi Jing
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Deju Kong
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Junli Wu
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Lu Feng
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Boyang Cao
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
| | - Lei Wang
- a TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, P.R. China.,b Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, P.R. China.,c Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, P.R. China
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60
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Mittal R, Pan DR, Parrish JM, Huang EH, Yang Y, Patel AP, Malhotra AK, Mittal J, Chhibber S, Harjai K. Local drug delivery in the urinary tract: current challenges and opportunities. J Drug Target 2018; 26:658-669. [PMID: 29251520 DOI: 10.1080/1061186x.2017.1419356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Drug delivery is an important consideration in disease treatment. There are many opportunities for novel methods and technologies to hold promising roles in overcoming traditional obstacles. Delivery systems functionalised to boast synergistic antimicrobial effects, specific targeting, and enhanced bioavailability allow for improved therapeutic potential and better patient outcomes. Many of these delivery modalities find clinical practicality in the field of urology, specifically in the treatment of urinary tract infections (UTIs) and offer advantages over conventional methods. The aim of this review article is to discuss the current modalities of treatment for UTIs and the recent technological advancements for optimising drug delivery. We focus on challenges that persist in drug delivery during UTIs including barriers to antimicrobial penetration, drug resistance, biofilm formation and specific targeting limitations. With a discussion on how emerging methods combat these concerns, we present an overview of potential therapies with special emphasis on nanoparticle-based applications.
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Affiliation(s)
- Rahul Mittal
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Debbie R Pan
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - James M Parrish
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Eric H Huang
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Yao Yang
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Amit P Patel
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Arul K Malhotra
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Jeenu Mittal
- a Department of Otolaryngology , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Sanjay Chhibber
- b Department of Microbiology , Panjab University , Chandigarh , India
| | - Kusum Harjai
- b Department of Microbiology , Panjab University , Chandigarh , India
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61
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Abstract
Extraintestinal pathogenic E. coli (ExPEC) present a major clinical problem that has emerged in the past years. Most of the infections are hospital or community-acquired and involve patients with a compromised immune system. The infective agents belong to a large number of strains of different serotypes that do not cross react. The seriousness of the infection is due to the fact that most of the infecting bacteria are highly antibiotic resistant. Here, we discuss the bacterial factors responsible for pathogenesis and potential means to combat the infections.
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Affiliation(s)
- Dvora Biran
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 39978, Tel Aviv, Israel
| | - Eliora Z Ron
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 39978, Tel Aviv, Israel.
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62
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Characterization, genetic regulation and production of cyanobacterial exopolysaccharides and its applicability for heavy metal removal. Carbohydr Polym 2018; 179:228-243. [DOI: 10.1016/j.carbpol.2017.09.091] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/15/2017] [Accepted: 09/26/2017] [Indexed: 11/18/2022]
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63
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Huang X, Chen C, Ren C, Li Y, Deng Y, Yang Y, Ding X. Identification and characterization of a locus putatively involved in colanic acid biosynthesis in Vibrio alginolyticus ZJ-51. BIOFOULING 2018; 34:1-14. [PMID: 29210309 DOI: 10.1080/08927014.2017.1400020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Colanic acid (CA) is a group I extracellular polysaccharide (EPS) that contributes to resistance against adverse environments in many members of the Enterobacteriaceae. In the present study, a genetic locus EPSC putatively involved in CA biosynthesis was identified in Vibrio alginolyticus ZJ-51, which undergoes colony morphology variation between translucent/smooth (ZJ-T) and opaque/rugose (ZJ-O). EPSC in ZJ-T carries 21 ORFs and resembles the CA cluster of Escherichia coli K-12. The deletion of EPSC led to decreased EPS and biofilm formation in both genetic backgrounds but no alternation of lipopolysaccharide. The loss of this locus also changed the colony morphology of ZJ-O on the 2216E plate and reduced the motility of ZJ-T. Compared with ZJ-T, ZJ-O lacks a 10-kb fragment (epsT) in EPSC containing homologs of wecA, wzx and wzy that are essential for O-antigen synthesis. However, the deletion or overexpression of epsT resulted in no change of colony morphology, biofilm formation or EPS production. This study reported at the first time a genetic locus EPSC that may be involved in colanic acid synthesis in V. alginolyticus ZJ-51, and found that it was related to EPS biosynthesis, biofilm formation, colony morphology and motility, which may shed light on the environmental adaptation of the vibrios.
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Affiliation(s)
- Xiaochun Huang
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
- b Guangdong Provincial Key Laboratory of Applied Marine Biology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , China
- d University of Chinese Academy of Sciences , Beijing , PR China
| | - Chang Chen
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
- b Guangdong Provincial Key Laboratory of Applied Marine Biology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , China
- c Xisha Deep Sea Marine Environment Observation and Research Station , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
| | - Chunhua Ren
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
| | - Yingying Li
- e College of Life Science and Technology , Jinan University , Guangzhou , PR China
| | - Yiqin Deng
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
- b Guangdong Provincial Key Laboratory of Applied Marine Biology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , China
- d University of Chinese Academy of Sciences , Beijing , PR China
| | - Yiying Yang
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
- b Guangdong Provincial Key Laboratory of Applied Marine Biology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , China
- d University of Chinese Academy of Sciences , Beijing , PR China
| | - Xiongqi Ding
- a Key Laboratory of Tropical Marine Bio-resources and Ecology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , PR China
- b Guangdong Provincial Key Laboratory of Applied Marine Biology , South China Sea Institution of Oceanology, University of Chinese Academy of Sciences , Guangzhou , China
- d University of Chinese Academy of Sciences , Beijing , PR China
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Three tandem promoters, together with IHF, regulate growth phase dependent expression of the Escherichia coli kps capsule gene cluster. Sci Rep 2017; 7:17924. [PMID: 29263430 PMCID: PMC5738388 DOI: 10.1038/s41598-017-17891-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/01/2017] [Indexed: 02/02/2023] Open
Abstract
In this study we characterise three tandem promoters (PR1-1, PR1-2 and PR1-3) within the PR1 regulatory region of the Escherichia coli kps capsule gene cluster. Transcription from promoter PR1-2 was dependent on the activity of the upstream promoter PR1-1, which activated PR1-2 via transcription coupled DNA supercoiling. During growth at 37 °C a temporal pattern of transcription from all three promoters was observed with maximum transcriptional activity evident during mid-exponential phase followed by a sharp decrease in activity as the cells enter stationary phase. The growth phase dependent transcription was regulated by Integration Host Factor (IHF), which bound within the PR1 region to repress transcription from PR1-2 and PR1-3. This pattern of transcription was mirrored by growth phase dependent expression of the K1 capsule. Overall these data reveal a complex pattern of transcriptional regulation for an important virulence factor with IHF playing a role in regulating growth phase expression.
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65
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Oliveira H, Costa AR, Konstantinides N, Ferreira A, Akturk E, Sillankorva S, Nemec A, Shneider M, Dötsch A, Azeredo J. Ability of phages to infectAcinetobacter calcoaceticus-Acinetobacter baumanniicomplex species through acquisition of different pectate lyase depolymerase domains. Environ Microbiol 2017; 19:5060-5077. [DOI: 10.1111/1462-2920.13970] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/22/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Hugo Oliveira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
| | - Ana R. Costa
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
| | - Nico Konstantinides
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
- Laboratory of Microbiology; Wageningen University; Stippeneng 6708 WE Wageningen The Netherlands
| | - Alice Ferreira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
| | - Ergun Akturk
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
| | - Sanna Sillankorva
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
| | - Alexandr Nemec
- Laboratory of Bacterial Genetics; National Institute of Public Health, Šrobárova 48; 100 42 Prague Czech Republic
| | - Mikhail Shneider
- Laboratory of Molecular Bioengineering, 16/10 Miklukho-Maklaya St; Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; 117997 Moscow Russia
| | - Andreas Dötsch
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT); Eggenstein-Leopoldshafen Germany
- Max Rubner-Institute, Institute for Physiologie and Biochemistry of Nutrition, Haid-und-Neu-Str. 9; 76131 Karlsruhe Germany
| | - Joana Azeredo
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira; University of Minho; 4710-057 Braga Portugal
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Semeraro EF, Devos JM, Porcar L, Forsyth VT, Narayanan T. In vivo analysis of the Escherichia coli ultrastructure by small-angle scattering. IUCRJ 2017; 4:751-757. [PMID: 29123677 PMCID: PMC5668860 DOI: 10.1107/s2052252517013008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/12/2017] [Indexed: 06/07/2023]
Abstract
The flagellated Gram-negative bacterium Escherichia coli is one of the most studied microorganisms. Despite extensive studies as a model prokaryotic cell, the ultrastructure of the cell envelope at the nanometre scale has not been fully elucidated. Here, a detailed structural analysis of the bacterium using a combination of small-angle X-ray and neutron scattering (SAXS and SANS, respectively) and ultra-SAXS (USAXS) methods is presented. A multiscale structural model has been derived by incorporating well established concepts in soft-matter science such as a core-shell colloid for the cell body, a multilayer membrane for the cell wall and self-avoiding polymer chains for the flagella. The structure of the cell envelope was resolved by constraining the model by five different contrasts from SAXS, and SANS at three contrast match points and full contrast. This allowed the determination of the membrane electron-density profile and the inter-membrane distances on a quantitative scale. The combination of USAXS and SAXS covers size scales from micrometres down to nanometres, enabling the structural elucidation of cells from the overall geometry down to organelles, thereby providing a powerful method for a non-invasive investigation of the ultrastructure. This approach may be applied for probing in vivo the effect of detergents, antibiotics and antimicrobial peptides on the bacterial cell wall.
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Affiliation(s)
| | | | | | - V. Trevor Forsyth
- Institut Laue–Langevin, 38042 Grenoble, France
- Life Sciences Department, Keele University, Staffordshire ST5 5BG, England
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Abstract
Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract and bloodstream infections and possesses an array of virulence factors for colonization, survival, and persistence. One such factor is the polysaccharide K capsule. Among the different K capsule types, the K1 serotype is strongly associated with UPEC infection. In this study, we completely sequenced the K1 UPEC urosepsis strain PA45B and employed a novel combination of a lytic K1 capsule-specific phage, saturated Tn5 transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing (TraDIS) to identify the complement of genes required for capsule production. Our analysis identified known genes involved in capsule biosynthesis, as well as two additional regulatory genes (mprA and lrhA) that we characterized at the molecular level. Mutation of mprA resulted in protection against K1 phage-mediated killing, a phenotype restored by complementation. We also identified a significantly increased unidirectional Tn5 insertion frequency upstream of the lrhA gene and showed that strong expression of LrhA induced by a constitutive Pcl promoter led to loss of capsule production. Further analysis revealed loss of MprA or overexpression of LrhA affected the transcription of capsule biosynthesis genes in PA45B and increased sensitivity to killing in whole blood. Similar phenotypes were also observed in UPEC strains UTI89 (K1) and CFT073 (K2), demonstrating that the effects were neither strain nor capsule type specific. Overall, this study defined the genome of a UPEC urosepsis isolate and identified and characterized two new regulatory factors that affect UPEC capsule production.IMPORTANCE Urinary tract infections (UTIs) are among the most common bacterial infections in humans and are primarily caused by uropathogenic Escherichia coli (UPEC). Many UPEC strains express a polysaccharide K capsule that provides protection against host innate immune factors and contributes to survival and persistence during infection. The K1 serotype is one example of a polysaccharide capsule type and is strongly associated with UPEC strains that cause UTIs, bloodstream infections, and meningitis. The number of UTIs caused by antibiotic-resistant UPEC is steadily increasing, highlighting the need to better understand factors (e.g., the capsule) that contribute to UPEC pathogenesis. This study describes the original and novel application of lytic capsule-specific phage killing, saturated Tn5 transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing to define the entire complement of genes required for capsule production in UPEC. Our comprehensive approach uncovered new genes involved in the regulation of this key virulence determinant.
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68
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Kononova SV. How Fucose of Blood Group Glycotopes Programs Human Gut Microbiota. BIOCHEMISTRY. BIOKHIMIIA 2017; 82:973-989. [PMID: 28988527 DOI: 10.1134/s0006297917090012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Formation of appropriate gut microbiota is essential for human health. The first two years of life is the critical period for this process. Selection of mutualistic microorganisms of the intestinal microbiota is controlled by the FUT2 and FUT3 genes that encode fucosyltransferases, enzymes responsible for the synthesis of fucosylated glycan structures of mucins and milk oligosaccharides. In this review, the mechanisms of the selection and maintenance of intestinal microorganisms that involve fucosylated oligosaccharides of breast milk and mucins of the newborn's intestine are described. Possible reasons for the use of fucose, and not sialic acid, as the major biological signal for the selection are also discussed.
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Affiliation(s)
- S V Kononova
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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69
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Guo Z, Huang J, Yan G, Lei L, Wang S, Yu L, Zhou L, Gao A, Feng X, Han W, Gu J, Yang J. Identification and Characterization of Dpo42, a Novel Depolymerase Derived from the Escherichia coli Phage vB_EcoM_ECOO78. Front Microbiol 2017; 8:1460. [PMID: 28824588 PMCID: PMC5539073 DOI: 10.3389/fmicb.2017.01460] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/20/2017] [Indexed: 11/13/2022] Open
Abstract
Biofilm formation, one of the most important virulence factors of pathogenic bacteria, protects bacteria against desiccation, antibiotics, phages and host immune responses. However, phage-derived depolymerases show antibiofilm activity and demonstrate great potential to treat infections caused by biofilm-forming bacteria. In this study, the Escherichia coli phage vB_EcoM_ECOO78 was isolated and characterised, and we observed its ability to lyse five out of 34 tested E. coli clinical isolates. The highest phage titre was observed at a multiplicity of infection of 10-5 and a burst size of approximately 74 plaque forming units (PFU)/infection. Electron micrographs indicated that vB_EcoM_ECOO78 belongs to the family Myoviridae. The presence of increasing halos surrounding the lysis plaques formed by vB_EcoM_ECOO78 indicated that this phage may encode a depolymerase. Based on a sequencing analysis, the complete genome of vB_EcoM_ECOO78 was found to be 41,289 bp in size, with a GC content of 53.07%. Additionally, vB_EcoM_ECOO78 has 56 predicted open reading frames, 51 (91.07%) of which are assumed to be functional. A BLAST analysis indicated that ORF42 of vB_EcoM_ECOO78 (Dpo42) has low identity with other reported phage-associated depolymerases. Dpo42 was expressed and purified as a soluble protein using E. coli BL21. The biofilm formation ability of E. coli isolates and the antibiofilm activity of Dpo42 were tested by performing spot assays and using a 96-well micro-titre plate method. Dpo42 degraded the capsular polysaccharides surrounding E. coli and exhibited dose-dependent biofilm-formation prevention activity. Based on these results, Dpo42 appears to be a novel phage-derived depolymerase that represents a new potential strategy for preventing E. coli biofilm formation.
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Affiliation(s)
- Zhimin Guo
- Department of Respiratory Medicine, The Second Hospital of Jilin UniversityChangchun, China.,Department of Clinical Laboratory, The First Hospital of Jilin UniversityChangchun, China
| | - Jing Huang
- Department of Clinical Laboratory, The First Hospital of Jilin UniversityChangchun, China
| | - Guangmou Yan
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Liancheng Lei
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Shuang Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Ling Yu
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Liang Zhou
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Anchong Gao
- Agricultural Experiment Base, Jilin UniversityChangchun, China
| | - Xin Feng
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Wenyu Han
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Jingmin Gu
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin UniversityChangchun, China
| | - Junling Yang
- Department of Respiratory Medicine, The Second Hospital of Jilin UniversityChangchun, China
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70
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Abundance and co-occurrence of extracellular capsules increase environmental breadth: Implications for the emergence of pathogens. PLoS Pathog 2017; 13:e1006525. [PMID: 28742161 PMCID: PMC5542703 DOI: 10.1371/journal.ppat.1006525] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/03/2017] [Accepted: 07/12/2017] [Indexed: 02/06/2023] Open
Abstract
Extracellular capsules constitute the outermost layer of many bacteria, are major virulence factors, and affect antimicrobial therapies. They have been used as epidemiological markers and recently became vaccination targets. Despite the efforts to biochemically serotype capsules in a few model pathogens, little is known of their taxonomic and environmental distribution. We developed, validated, and made available a computational tool, CapsuleFinder, to identify capsules in genomes. The analysis of over 2500 prokaryotic genomes, accessible in a database, revealed that ca. 50% of them—including Archaea—encode a capsule. The Wzx/Wzy-dependent capsular group was by far the most abundant. Surprisingly, a fifth of the genomes encode more than one capsule system—often from different groups—and their non-random co-occurrence suggests the existence of negative and positive epistatic interactions. To understand the role of multiple capsules, we queried more than 6700 metagenomes for the presence of species encoding capsules and showed that their distribution varied between environmental categories and, within the human microbiome, between body locations. Species encoding capsules, and especially those encoding multiple capsules, had larger environmental breadths than the other species. Accordingly, capsules were more frequent in environmental bacteria than in pathogens and, within the latter, they were more frequent among facultative pathogens. Nevertheless, capsules were frequent in clinical samples, and were usually associated with fast-growing bacteria with high infectious doses. Our results suggest that capsules increase the environmental range of bacteria and make them more resilient to environmental perturbations. Capsules might allow opportunistic pathogens to profit from empty ecological niches or environmental perturbations, such as those resulting from antibiotic therapy, to colonize the host. Capsule-associated virulence might thus be a by-product of environmental adaptation. Understanding the role of capsules in natural environments might enlighten their function in pathogenesis. Extracellular capsules protect bacterial cells from external aggressions such as antibiotics or desiccation, but can also be targeted by vaccines. Since little was known about their frequency across Prokaryotes, we created and made freely available a computational tool, CapsuleFinder, to identify them from genomic data. Surprisingly, its use showed that many bacterial strains, especially those with the largest genomes, encode several capsules. The frequencies of the different combinations of capsule groups depended strongly on the phyla and the groups themselves, suggesting the existence of epistatic interactions between capsules. Bacteria encoding capsule systems were found in many natural environments, and were frequent in the human microbiome. In contrast to their frequent association with virulence, we found many more capsules in non-pathogens or facultative pathogens than among obligatory pathogens. We suggest that capsules increase the environmental breadth of bacteria thereby facilitating host colonization by opportunistic pathogens.
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71
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Baldi F, Gallo M, Daniele S, Battistel D, Faleri C, Kodre A, Arčon I. An extracellular polymeric substance quickly chelates mercury(II) with N-heterocyclic groups. CHEMOSPHERE 2017; 176:296-304. [PMID: 28273537 DOI: 10.1016/j.chemosphere.2017.02.093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 05/26/2023]
Abstract
A strain of Klebsiella oxytoca DSM 29614 is grown on sodium citrate in the presence of 50 mg l-1 of Hg as Hg(NO3)2. During growth, the strain produces an extracellular polymeric substance (EPS), constituted by a mixture of proteins and a specific exopolysaccharide. The protein components, derived from the outer membrane of cells, are co-extracted with the extracellular exopolysaccharide using ethanol. The extracted EPS contains 7.5% of Hg (total amount). This indicates that EPS is an excellent material for the biosorption of Hg2+, through chemical complexation with the EPS components. The binding capacity of these species towards Hg2+ is studied by cyclic voltammetry, and Hg L3-edge XANES and EXAFS spectroscopy. The results found indicate that Hg2+ is mainly bound to the nitrogen of the imidazole ring or other N-heterocycle compounds. The hydroxyl moities of sugars and/or the carboxyl groups of two glucuronic acids in the polysaccharide can also play an important role in sequestring Hg2+ ions. However, N-heterocyclic groups of proteins bind Hg2+ faster than hydroxyl and carboxyl groups of the polysaccharide.
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Affiliation(s)
- Franco Baldi
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre Venezia, Italy.
| | - Michele Gallo
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre Venezia, Italy
| | - Salvatore Daniele
- Dipartimento di Scienze Molecolari e Nanosistemi, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre Venezia, Italy
| | - Dario Battistel
- Dipartimento di Scienze Ambientali, Informatica e Statistica, University Cà Foscari Venezia, Via Torino 155, 30172, Mestre Venezia, Italy; Institute for the Dynamics of Environmental Processes, IDPA/CNR, Via Torino, 155, 30172, Mestre Venezia, Venice, Italy
| | - Claudia Faleri
- Dipartimento Scienze della Vita, Siena University, Via Mattioli 4, 53100, Siena, Italy
| | - Alojz Kodre
- Jozef Stefan Institute, Jamova 39, Ljubljana, Slovenia; Faculty of Mathematics & Physics, University of Ljubljana, Slovenia
| | - Iztok Arčon
- Jozef Stefan Institute, Jamova 39, Ljubljana, Slovenia; University of Nova Gorica, Vipavska 13, Nova Gorica, Slovenia
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72
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'Omic' Approaches to Study Uropathogenic Escherichia coli Virulence. Trends Microbiol 2017; 25:729-740. [PMID: 28550944 DOI: 10.1016/j.tim.2017.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/10/2017] [Accepted: 04/21/2017] [Indexed: 01/21/2023]
Abstract
Uropathogenic Escherichia coli (UPEC) is a pathogen of major significance to global human health and is strongly associated with rapidly increasing antibiotic resistance. UPEC is the primary cause of urinary tract infection (UTI), a disease that involves a complicated pathogenic pathway of extracellular and intracellular lifestyles during interaction with the host. The application of multiple 'omic' technologies, including genomics, transcriptomics, proteomics, and metabolomics, has provided enormous knowledge to our understanding of UPEC biology. Here we outline this progress and present a view for future developments using these exciting forefront technologies to fully comprehend UPEC pathogenesis in the context of infection.
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73
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Peptidoglycan Association of Murein Lipoprotein Is Required for KpsD-Dependent Group 2 Capsular Polysaccharide Expression and Serum Resistance in a Uropathogenic Escherichia coli Isolate. mBio 2017; 8:mBio.00603-17. [PMID: 28536290 PMCID: PMC5442458 DOI: 10.1128/mbio.00603-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Murein lipoprotein (Lpp) and peptidoglycan-associated lipoprotein (Pal) are major outer membrane lipoproteins in Escherichia coli. Their roles in cell-envelope integrity have been documented in E. coli laboratory strains, and while Lpp has been linked to serum resistance in vitro, the underlying mechanism has not been established. Here, lpp and pal mutants of uropathogenic E. coli strain CFT073 showed reduced survival in a mouse bacteremia model, but only the lpp mutant was sensitive to serum killing in vitro. The peptidoglycan-bound Lpp form was specifically required for preventing complement-mediated bacterial lysis in vitro and complement-mediated clearance in vivo. Compared to the wild-type strain, the lpp mutant had impaired K2 capsular polysaccharide production and was unable to respond to exposure to serum by elevating capsular polysaccharide amounts. These properties correlated with altered cellular distribution of KpsD, the predicted outer membrane translocon for “group 2” capsular polysaccharides. We identified a novel Lpp-dependent association between functional KpsD and peptidoglycan, highlighting important interplay between cell envelope components required for resistance to complement-mediated lysis in uropathogenic E. coli isolates. Uropathogenic E. coli (UPEC) isolates represent a significant cause of nosocomial urinary tract and bloodstream infections. Many UPEC isolates are resistant to serum killing. Here, we show that a major cell-envelope lipoprotein (murein lipoprotein) is required for serum resistance in vitro and for complement-mediated bacterial clearance in vivo. This is mediated, in part, through a novel mechanism by which murein lipoprotein affects the proper assembly of a key component of the machinery involved in production of “group 2” capsules. The absence of murein lipoprotein results in impaired production of the capsule layer, a known participant in complement resistance. These results demonstrate an important role for murein lipoprotein in complex interactions between different outer membrane biogenesis pathways and further highlight the importance of lipoprotein assembly and transport in bacterial pathogenesis.
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74
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Abreu AG, Barbosa AS. How Escherichia coli Circumvent Complement-Mediated Killing. Front Immunol 2017; 8:452. [PMID: 28473832 PMCID: PMC5397495 DOI: 10.3389/fimmu.2017.00452] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 12/19/2022] Open
Abstract
Complement is a crucial arm of the innate immune response against invading bacterial pathogens, and one of its main functions is to recognize and destroy target cells. Similar to other pathogens, Escherichia coli has evolved mechanisms to overcome complement activation. It is well known that capsular polysaccharide may confer resistance to complement-mediated killing and phagocytosis, being one of the strategies adopted by this bacterium to survive in serum. In addition, proteases produced by E. coli have been shown to downregulate the complement system. Pic, an autotransporter secreted by different pathogens in the Enterobacteriaceae family, is able to cleave C2, C3/C3b, and C4/C4b and works synergistically with human Factor I and Factor H (FH), thereby promoting inactivation of C3b. Extracellular serine protease P, a serine protease of enterohemorrhagic E. coli (EHEC), downregulates complement activation by cleaving C3/C3b and C5. StcE, a metalloprotease secreted by EHEC, inhibits the classical complement-mediated cell lysis by potentiating the action of C1 inhibitor, and the periplasmic protease Prc contributes to E. coli complement evasion by interfering with the classical pathway activation and by preventing membrane attack complex deposition. Finally, it has been described that E. coli proteins interact with negative complement regulators to modulate complement activation. The functional consequences resulting from the interaction of outer membrane protein A, new lipoprotein I, outer membrane protein W, and Stx2 with proteins of the FH family and C4b-binding protein (C4BP) are discussed in detail. In brief, in this review, we focused on the different mechanisms used by pathogenic E. coli to circumvent complement attack, allowing these bacteria to promote a successful infection.
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Affiliation(s)
- Afonso G Abreu
- Programa de Pós-Graduação em Biologia Parasitária, CEUMA University, São Luís, Brazil.,Programa de Pós-Graduação em Ciências da Saúde, Federal University of Maranhão, São Luís, Brazil
| | - Angela S Barbosa
- Laboratory of Bacteriology, Butantan Institute, São Paulo, Brazil
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75
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Catalán-Nájera JC, Garza-Ramos U, Barrios-Camacho H. Hypervirulence and hypermucoviscosity: Two different but complementary Klebsiella spp. phenotypes? Virulence 2017; 8:1111-1123. [PMID: 28402698 DOI: 10.1080/21505594.2017.1317412] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Since the hypermucoviscous variants of Klebsiella pneumoniae were first reported, many cases of primary liver abscesses and other invasive infections caused by this pathogen have been described worldwide. Hypermucoviscosity is a phenotypic feature characterized by the formation of a viscous filament ≥5 mm when a bacterial colony is stretched by a bacteriological loop; this is the so-called positive string test. Hypermucoviscosity appears to be associated with this unusual and aggressive type of infection, and therefore, the causal strains are considered hypervirulent. Since these first reports, the terms hypermucoviscosity and hypervirulence have often been used synonymously. However, new evidence has suggested that hypermucoviscosity and hypervirulence are 2 different phenotypes that should not be used synonymously. Moreover, it is important to establish that a negative string test is insufficient in determining whether a strain is or is not hypervirulent. On the other hand, hypervirulence- and hypermucoviscosity-associated genes must be identified, considering that these phenotypes correspond to 2 different phenomena, regardless of whether they can act in synergy under certain circumstances. Therefore, it is essential to quickly identify the genetic determinants behind the hypervirulent phenotype to develop effective methodologies that can diagnose in a prompt and effective way these hypervirulent variants of K. pneumoniae.
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Affiliation(s)
- Juan Carlos Catalán-Nájera
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
| | - Ulises Garza-Ramos
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
| | - Humberto Barrios-Camacho
- a Departamento de Diagnostico Epidemiologico, Centro de Investigacion sobre Enfermedades Infecciosas (CISEI) , Instituto Nacional de Salud Pública (INSP) , Cuernavaca, Morelos , México
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76
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Senchenkova SN, Zhang Y, Perepelov AV, Guo X, Shashkov AS, Liu B, Knirel YA. Structure and Biosynthesis Gene Cluster of the O-Antigen of Escherichia coli O12. BIOCHEMISTRY (MOSCOW) 2017; 81:401-6. [PMID: 27293097 DOI: 10.1134/s0006297916040106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Two polysaccharides were isolated from Escherichia coli O12, the major being identified as the O12-antigen and the minor as the K5-antigen. The polysaccharides were studied by sugar analysis, Smith degradation, and one- and two-dimensional (1)H and (13)C NMR spectroscopy. As a result, the following structure of the O12-polysaccharide was elucidated, which, to our knowledge, has not been hitherto found in bacterial carbohydrates: →2)-β-d-Glcp-(1→6)-α-d-GlcpNAc-(1→3)-α-l-FucpNAc-(1→3)-β-d-GlcpNAc-(1→. The →4)-β-d-GlcpA-(1→4)-α-d-GlcpNAc-(1→ structure established for the K5-polysaccharide (heparosan) is previously known. Functions of genes in the O-antigen biosynthesis gene cluster of E. coli O12 were assigned by comparison with sequences in the available databases and found to be consistent with the O12-polysaccharide structure.
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Affiliation(s)
- S N Senchenkova
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, 119991, Russia.
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Hufnagel DA, Evans ML, Greene SE, Pinkner JS, Hultgren SJ, Chapman MR. The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli. J Bacteriol 2016; 198:3329-3334. [PMID: 27698083 PMCID: PMC5116936 DOI: 10.1128/jb.00652-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/27/2016] [Indexed: 12/24/2022] Open
Abstract
The extracellular matrix protects Escherichia coli from immune cells, oxidative stress, predation, and other environmental stresses. Production of the E. coli extracellular matrix is regulated by transcription factors that are tuned to environmental conditions. The biofilm master regulator protein CsgD upregulates curli and cellulose, the two major polymers in the extracellular matrix of uropathogenic E. coli (UPEC) biofilms. We found that cyclic AMP (cAMP) regulates curli, cellulose, and UPEC biofilms through csgD The alarmone cAMP is produced by adenylate cyclase (CyaA), and deletion of cyaA resulted in reduced extracellular matrix production and biofilm formation. The catabolite repressor protein (CRP) positively regulated csgD transcription, leading to curli and cellulose production in the UPEC isolate, UTI89. Glucose, a known inhibitor of CyaA activity, blocked extracellular matrix formation when added to the growth medium. The mutant strains ΔcyaA and Δcrp did not produce rugose biofilms, pellicles, curli, cellulose, or CsgD. Three putative CRP binding sites were identified within the csgD-csgB intergenic region, and purified CRP could gel shift the csgD-csgB intergenic region. Additionally, we found that CRP binded upstream of kpsMT, which encodes machinery for K1 capsule production. Together our work shows that cAMP and CRP influence E. coli biofilms through transcriptional regulation of csgD IMPORTANCE The catabolite repressor protein (CRP)-cyclic AMP (cAMP) complex influences the transcription of ∼7% of genes on the Escherichia coli chromosome (D. Zheng, C. Constantinidou, J. L. Hobman, and S. D. Minchin, Nucleic Acids Res 32:5874-5893, 2004, https://dx.doi.org/10.1093/nar/gkh908). Glucose inhibits E. coli biofilm formation, and ΔcyaA and Δcrp mutants show impaired biofilm formation (D. W. Jackson, J.W. Simecka, and T. Romeo, J Bacteriol 184:3406-3410, 2002, https://dx.doi.org/10.1128/JB.184.12.3406-3410.2002). We determined that the cAMP-CRP complex regulates curli and cellulose production and the formation of rugose and pellicle biofilms through csgD Additionally, we propose that cAMP may work as a signaling compound for uropathogenic E. coli (UPEC) to transition from the bladder lumen to inside epithelial cells for intracellular bacterial community formation through K1 capsule regulation.
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Affiliation(s)
- David A Hufnagel
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Margery L Evans
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Sarah E Greene
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jerome S Pinkner
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Scott J Hultgren
- Department of Molecular Microbiology and Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
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78
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Moraïs S, Cockburn DW, Ben-David Y, Koropatkin NM, Martens EC, Duncan SH, Flint HJ, Mizrahi I, Bayer EA. Lysozyme activity of theRuminococcus champanellensiscellulosome. Environ Microbiol 2016; 18:5112-5122. [DOI: 10.1111/1462-2920.13501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 08/16/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Sarah Moraïs
- Biomolecular Sciences Department; The Weizmann Institute of Science; Rehovot Israel
| | - Darrell W. Cockburn
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor MI 48109 USA
| | - Yonit Ben-David
- Biomolecular Sciences Department; The Weizmann Institute of Science; Rehovot Israel
| | - Nicole M. Koropatkin
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor MI 48109 USA
| | - Eric C. Martens
- Department of Microbiology and Immunology; University of Michigan Medical School; Ann Arbor MI 48109 USA
| | - Sylvia H. Duncan
- Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen; Aberdeen UK
| | - Harry J. Flint
- Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen; Aberdeen UK
| | - Itzhak Mizrahi
- The Department of Life Sciences & the National Institute for Biotechnology in the Negev; Ben-Gurion University of the Negev; Beer-Sheva 84105 Israel
| | - Edward A. Bayer
- Biomolecular Sciences Department; The Weizmann Institute of Science; Rehovot Israel
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79
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Chesterman C, Jia Z. Purification, characterization, and crystallization of membrane bound Escherichia coli tyrosine kinase. Protein Expr Purif 2016; 125:34-42. [DOI: 10.1016/j.pep.2015.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/28/2015] [Accepted: 08/29/2015] [Indexed: 11/28/2022]
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80
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Zhao X, Chen Z, Gu G, Guo Z. Recent advances in the research of bacterial glucuronosyltransferases. J Carbohydr Chem 2016. [DOI: 10.1080/07328303.2016.1205597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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81
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Sachdeva S, Kolimi N, Nair SA, Rathinavelan T. Key diffusion mechanisms involved in regulating bidirectional water permeation across E. coli outer membrane lectin. Sci Rep 2016; 6:28157. [PMID: 27320406 PMCID: PMC4913347 DOI: 10.1038/srep28157] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 05/31/2016] [Indexed: 12/27/2022] Open
Abstract
Capsular polysaccharides (CPSs) are major bacterial virulent determinants that facilitate host immune evasion. E. coli group1 K30CPS is noncovalently attached to bacterial surface by Wzi, a lectin. Intriguingly, structure based phylogenetic analysis indicates that Wzi falls into porin superfamily. Molecular dynamics (MD) simulations further shed light on dual role of Wzi as it also functions as a bidirectional passive water specific porin. Such a functional role of Wzi was not realized earlier, due to the occluded pore. While five water specific entry points distributed across extracellular & periplasmic faces regulate the water diffusion involving different mechanisms, a luminal hydrophobic plug governs water permeation across the channel. Coincidently, MD observed open state structure of “YQF” triad is seen in sugar-binding site of sodium-galactose cotransporters, implicating its involvement in K30CPS surface anchorage. Importance of Loop 5 (L5) in membrane insertion is yet another highlight. Change in water diffusion pattern of periplasmic substitution mutants suggests Wzi’s role in osmoregulation by aiding in K30CPS hydration, corroborating earlier functional studies. Water molecules located inside β-barrel of Wzi crystal structure further strengthens the role of Wzi in osmoregulation. Thus, interrupting water diffusion or L5 insertion may reduce bacterial virulence.
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Affiliation(s)
- Shivangi Sachdeva
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State 502285, India
| | - Narendar Kolimi
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State 502285, India
| | - Sanjana Anilkumar Nair
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State 502285, India
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82
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Genetic and Molecular Basis of Kingella kingae Encapsulation. Infect Immun 2016; 84:1775-1784. [PMID: 27045037 DOI: 10.1128/iai.00128-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 03/28/2016] [Indexed: 12/30/2022] Open
Abstract
Kingella kingae is a common cause of invasive disease in young children and was recently found to produce a polysaccharide capsule containing N-acetylgalactosamine (GalNAc) and β-3-deoxy-d-manno-octulosonic acid (βKdo). Given the role of capsules as important virulence factors and effective vaccine antigens, we set out to determine the genetic determinants of K. kingae encapsulation. Using a transposon library and a screen for nonencapsulated mutants, we identified the previously identified ctrABCD (ABC transporter) operon, a lipA (kpsC)-like gene, a lipB (kpsS)-like gene, and a putative glycosyltransferase gene designated csaA (capsule synthesis type a gene A). These genes were found to be present at unlinked locations scattered throughout the genome, an atypical genetic arrangement for Gram-negative bacteria that elaborate a capsule dependent on an ABC-type transporter for surface localization. The csaA gene product contains a predicted glycosyltransferase domain with structural homology to GalNAc transferases and a predicted capsule synthesis domain with structural homology to Kdo transferases, raising the possibility that this enzyme is responsible for alternately linking GalNAc to βKdo and βKdo to GalNAc. Consistent with this conclusion, mutation of the DXD motif in the GalNAc transferase domain and of the HP motif in the Kdo transferase domain resulted in a loss of encapsulation. Examination of intracellular and surface-associated capsule in deletion mutants and complemented strains further implicated the lipA (kpsC)-like gene, the lipB (kpsS)-like gene, and the csaA gene in K. kingae capsule production. These data define the genetic requirements for encapsulation in K. kingae and demonstrate an atypical organization of capsule synthesis, assembly, and export genes.
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Abstract
Microbes produce a biofilm matrix consisting of proteins, extracellular DNA, and polysaccharides that is integral in the formation of bacterial communities. Historical studies of polysaccharides revealed that their overproduction often alters the colony morphology and can be diagnostic in identifying certain species. The polysaccharide component of the matrix can provide many diverse benefits to the cells in the biofilm, including adhesion, protection, and structure. Aggregative polysaccharides act as molecular glue, allowing the bacterial cells to adhere to each other as well as surfaces. Adhesion facilitates the colonization of both biotic and abiotic surfaces by allowing the bacteria to resist physical stresses imposed by fluid movement that could separate the cells from a nutrient source. Polysaccharides can also provide protection from a wide range of stresses, such as desiccation, immune effectors, and predators such as phagocytic cells and amoebae. Finally, polysaccharides can provide structure to biofilms, allowing stratification of the bacterial community and establishing gradients of nutrients and waste products. This can be advantageous for the bacteria by establishing a heterogeneous population that is prepared to endure stresses created by the rapidly changing environments that many bacteria encounter. The diverse range of polysaccharide structures, properties, and roles highlight the importance of this matrix constituent to the successful adaptation of bacteria to nearly every niche. Here, we present an overview of the current knowledge regarding the diversity and benefits that polysaccharide production provides to bacterial communities within biofilms.
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84
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Huang H, Liu X, Lv S, Zhong W, Zhang F, Linhardt RJ. Recombinant Escherichia coli K5 strain with the deletion of waaR gene decreases the molecular weight of the heparosan capsular polysaccharide. Appl Microbiol Biotechnol 2016; 100:7877-85. [PMID: 27079575 DOI: 10.1007/s00253-016-7511-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 03/23/2016] [Accepted: 03/25/2016] [Indexed: 01/02/2023]
Abstract
Heparosan, the capsular polysaccharide of Escherichia coli K5 having a carbohydrate backbone similar to that of heparin, has become a potential precursor for bioengineering heparin. In the heparosan biosynthesis pathway, the gene waaR encoding α-1-, 2- glycosyltransferase catalyze s the third glucosyl residues linking to the oligosaccharide chain. In the present study, a waaR deletion mutant of E. coli K5 was constructed. The mutant showed improvement of capsule polysaccharide yield. It is interesting that the heparosan molecular weight of the mutant is reduced and may become more suitable as a precursor for the production of low molecular weight heparin derived from the wild-type K5 capsular polysaccharide.
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Affiliation(s)
- Haichan Huang
- College of Biological Engineering, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Xiaobo Liu
- College of Biological Engineering, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Shencong Lv
- College of Biological Engineering, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Weihong Zhong
- College of Biological Engineering, Zhejiang University of Technology, Hangzhou, 310032, China.
| | - Fuming Zhang
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Robert J Linhardt
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.,Department of Biological Science, Departments of Chemistry and Chemical Biology and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
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85
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Escherichia coli O104 in Feedlot Cattle Feces: Prevalence, Isolation and Characterization. PLoS One 2016; 11:e0152101. [PMID: 27010226 PMCID: PMC4807062 DOI: 10.1371/journal.pone.0152101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/08/2016] [Indexed: 11/19/2022] Open
Abstract
Escherichia coli O104:H4, an hybrid pathotype of Shiga toxigenic and enteroaggregative E. coli, involved in a major foodborne outbreak in Germany in 2011, has not been detected in cattle feces. Serogroup O104 with H type other than H4 has been reported to cause human illnesses, but their prevalence and characteristics in cattle have not been reported. Our objectives were to determine the prevalence of E. coli O104 in feces of feedlot cattle, by culture and PCR detection methods, and characterize the isolated strains. Rectal fecal samples from a total of 757 cattle originating from 29 feedlots were collected at a Midwest commercial slaughter plant. Fecal samples, enriched in E. coli broth, were subjected to culture and PCR methods of detection. The culture method involved immunomagnetic separation with O104-specific beads and plating on a selective chromogenic medium, followed by serogroup confirmation of pooled colonies by PCR. If pooled colonies were positive for the wzxO104 gene, then colonies were tested individually to identify wzxO104-positive serogroup and associated genes of the hybrid strains. Extracted DNA from feces were also tested by a multiplex PCR to detect wzxO104-positive serogroup and associated major genes of the O104 hybrid pathotype. Because wzxO104 has been shown to be present in E. coli O8/O9/O9a, wzxO104-positive isolates and extracted DNA from fecal samples were also tested by a PCR targeting wbdDO8/O9/O9a, a gene specific for E. coli O8/O9/O9a serogroups. Model-adjusted prevalence estimates of E. coli O104 (positive for wzxO104 and negative for wbdDO8/O9/O9a) at the feedlot level were 5.7% and 21.2%, and at the sample level were 0.5% and 25.9% by culture and PCR, respectively. The McNemar's test indicated that there was a significant difference (P < 0.01) between the proportions of samples that tested positive for wzxO104 and samples that were positive for wzxO104, but negative for wbdDO8/O9/O9a by PCR and culture methods. A total of 143 isolates, positive for the wzxO104, were obtained in pure culture from 146 positive fecal samples. Ninety-two of the 143 isolates (64.3%) also tested positive for the wbdDO8/O9/O9a, indicating that only 51 (35.7%) isolates truly belonged to the O104 serogroup (positive for wzxO104 and negative for wbdDO8/O9/O9a). All 51 isolates tested negative for eae, and 16 tested positive for stx1 gene of the subtype 1c. Thirteen of the 16 stx1-positive O104 isolates were from one feedlot. The predominant serotype was O104:H7. Pulsed-field gel electrophoresis analysis indicated that stx1-positive O104:H7 isolates had 62.4% homology to the German outbreak strain and 67.9% to 77.5% homology to human diarrheagenic O104:H7 strains. The 13 isolates obtained from the same feedlot were of the same PFGE subtype with 100% Dice similarity. Although cattle do not harbor the O104:H4 pathotype, they do harbor and shed Shiga toxigenic O104 in the feces and the predominant serotype was O104:H7.
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86
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Zacchè MM, Giarenis I. Therapies in early development for the treatment of urinary tract inflammation. Expert Opin Investig Drugs 2016; 25:531-40. [DOI: 10.1517/13543784.2016.1161024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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87
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Mijakovic I, Grangeasse C, Turgay K. Exploring the diversity of protein modifications: special bacterial phosphorylation systems. FEMS Microbiol Rev 2016; 40:398-417. [PMID: 26926353 DOI: 10.1093/femsre/fuw003] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/02/2016] [Indexed: 12/31/2022] Open
Abstract
Protein modifications not only affect protein homeostasis but can also establish new cellular protein functions and are important components of complex cellular signal sensing and transduction networks. Among these post-translational modifications, protein phosphorylation represents the one that has been most thoroughly investigated. Unlike in eukarya, a large diversity of enzyme families has been shown to phosphorylate and dephosphorylate proteins on various amino acids with different chemical properties in bacteria. In this review, after a brief overview of the known bacterial phosphorylation systems, we focus on more recently discovered and less widely known kinases and phosphatases. Namely, we describe in detail tyrosine- and arginine-phosphorylation together with some examples of unusual serine-phosphorylation systems and discuss their potential role and function in bacterial physiology, and regulatory networks. Investigating these unusual bacterial kinase and phosphatases is not only important to understand their role in bacterial physiology but will help to generally understand the full potential and evolution of protein phosphorylation for signal transduction, protein modification and homeostasis in all cellular life.
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Affiliation(s)
- Ivan Mijakovic
- Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2970 Hørsholm, Denmark
| | - Christophe Grangeasse
- Unité Microbiologie Moléculaire et Biochimie Structurale, UMR 5086-CNRS/ Université Lyon 1, Lyon 69367, France
| | - Kürşad Turgay
- Institut für Mikrobiologie, Leibniz Universität Hannover, D-30419 Hannover, Germany
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Yeh KM, Chiu SK, Lin CL, Huang LY, Tsai YK, Chang JC, Lin JC, Chang FY, Siu LK. Surface antigens contribute differently to the pathophysiological features in serotype K1 and K2 Klebsiella pneumoniae strains isolated from liver abscesses. Gut Pathog 2016; 8:4. [PMID: 26893615 PMCID: PMC4758166 DOI: 10.1186/s13099-016-0085-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/12/2016] [Indexed: 01/05/2023] Open
Abstract
Background The virulence role of surface antigens in a single serotype of Klebsiella pneumoniae strain have been studied, but little is known about whether their contribution will vary with serotype. Method To investigate the role of K and O antigen in hyper-virulent strains, we constructed O and K antigen deficient mutants from serotype K1 STL43 and K2 TSGH strains from patients with liver abscess, and characterized their virulence in according to the abscess formation and resistance to neutrophil phagocytosis, serum, and bacterial clearance in liver. Results Both of K1 and K2-antigen mutants lost their wildtype resistance to neutrophil phagocytosis and hepatic clearance, and failed to cause abscess formation. K2-antigen mutant became serum susceptible while K1-antigen mutant maintained its resistance to serum killing. The amount of glucuronic acid, indicating the amount of capsular polysaccharide (CPS, K antigen), was inversed proportional to the rate of phagocytosis. O-antigen mutant of serotype K1 strains had significantly more amount of CPS, and more resistant to neutrophil phagocytosis than its wildtype counterpart. O-antigen mutants of serotype K1 and K2 strains lost their wildtype serum resistance, and kept resistant to neutrophil phagocytosis. While both mutants lacked the same O1 antigen, O-antigen mutant of serotype K1 became susceptible to liver clearance and cause mild abscess formation, but its serotype K2 counterpart maintained these wildtype virulence. Conclusion We conclude that the contribution of surface antigens to virulence of K. pneumoniae strains varies with serotypes.
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Affiliation(s)
- Kuo-Ming Yeh
- Department of Internal Medicine, Division of Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan ; Infection Control Office, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan
| | - Sheng-Kung Chiu
- Department of Internal Medicine, Division of Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan
| | - Chii-Lan Lin
- School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan ; Department of Internal Medicine, Division of Pulmonary Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Li-Yueh Huang
- Institute of Infectious Diseases and Vaccine Research, National Health Research Institutes, 35 Keyan Road, Zhunan, 35053 Miaoli, Taiwan
| | - Yu-Kuo Tsai
- Institute of Infectious Diseases and Vaccine Research, National Health Research Institutes, 35 Keyan Road, Zhunan, 35053 Miaoli, Taiwan
| | - Jen-Chang Chang
- Institute of Infectious Diseases and Vaccine Research, National Health Research Institutes, 35 Keyan Road, Zhunan, 35053 Miaoli, Taiwan
| | - Jung-Chung Lin
- Department of Internal Medicine, Division of Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan
| | - Feng-Yee Chang
- Department of Internal Medicine, Division of Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan
| | - Leung-Kei Siu
- Department of Internal Medicine, Division of Infectious Diseases and Tropical Medicine, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Kung Road, Neihu, 114 Taipei City Taiwan ; Institute of Infectious Diseases and Vaccine Research, National Health Research Institutes, 35 Keyan Road, Zhunan, 35053 Miaoli, Taiwan ; Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
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Zhang YC, Zhang Y, Zhu BR, Zhang BW, Ni C, Zhang DY, Huang Y, Pang E, Lin K. Genome sequences of two closely related strains of Escherichia coli K-12 GM4792. Stand Genomic Sci 2015; 10:125. [PMID: 26664654 PMCID: PMC4675052 DOI: 10.1186/s40793-015-0114-x] [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] [Received: 06/05/2015] [Accepted: 11/09/2015] [Indexed: 11/15/2022] Open
Abstract
Escherichia coli lab strains K-12 GM4792 Lac+ and GM4792 Lac- carry opposite lactose markers, which are useful for distinguishing evolved lines as they produce different colored colonies. The two closely related strains are chosen as ancestors for our ongoing studies of experimental evolution. Here, we describe the genome sequences, annotation, and features of GM4792 Lac+ and GM4792 Lac-. GM4792 Lac+ has a 4,622,342-bp long chromosome with 4,061 protein-coding genes and 83 RNA genes. Similarly, the genome of GM4792 Lac- consists of a 4,621,656-bp chromosome containing 4,043 protein-coding genes and 74 RNA genes. Genome comparison analysis reveals that the differences between GM4792 Lac+ and GM4792 Lac- are minimal and limited to only the targeted lac region. Moreover, a previous study on competitive experimentation indicates the two strains are identical or nearly identical in survivability except for lactose utilization in a nitrogen-limited environment. Therefore, at both a genetic and a phenotypic level, GM4792 Lac+ and GM4792 Lac-, with opposite neutral markers, are ideal systems for future experimental evolution studies.
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Affiliation(s)
- Yan-Cong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Yan Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China ; Present address: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Bi-Ru Zhu
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Bo-Wen Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Chuan Ni
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China ; Present address: The second high school attached to Beijing Normal University, Beijing, 100192 China
| | - Da-Yong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Ying Huang
- State Key Laboratory for Infectious Disease Prevention and Control, and National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206 China
| | - Erli Pang
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
| | - Kui Lin
- State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Street, Beijing, 100875 China
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90
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Park YD, Williamson PR. Masking the Pathogen: Evolutionary Strategies of Fungi and Their Bacterial Counterparts. J Fungi (Basel) 2015; 1:397-421. [PMID: 29376918 PMCID: PMC5753132 DOI: 10.3390/jof1030397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 11/21/2022] Open
Abstract
Pathogens reduce immune recognition of their cell surfaces using a variety of inert structural polysaccharides. For example, capsular polysaccharides play critical roles in microbial survival strategies. Capsules are widely distributed among bacterial species, but relatively rare in eukaryotic microorganisms, where they have evolved considerable complexity in structure and regulation and are exemplified by that of the HIV/AIDS-related fungus Cryptococcus neoformans. Endemic fungi that affect normal hosts such as Histoplasma capsulatum and Blastomyces dermatitidis have also evolved protective polysaccharide coverings in the form of immunologically inert α-(1,3)-glucan polysaccharides to protect their more immunogenic β-(1,3)-glucan-containing cell walls. In this review we provide a comparative update on bacterial and fungal capsular structures and immunogenic properties as well as the polysaccharide masking strategies of endemic fungal pathogens.
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Affiliation(s)
- Yoon-Dong Park
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
| | - Peter R Williamson
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
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91
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Araújo GRDS, Fontes GN, Leão D, Rocha GM, Pontes B, Sant'Anna C, de Souza W, Frases S. Cryptococcus neoformans capsular polysaccharides form branched and complex filamentous networks viewed by high-resolution microscopy. J Struct Biol 2015; 193:75-82. [PMID: 26655746 DOI: 10.1016/j.jsb.2015.11.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/28/2015] [Accepted: 11/30/2015] [Indexed: 11/17/2022]
Abstract
Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals. Its main virulence factor is an extracellular polysaccharide capsule whose structure, assembly and dynamics remain poorly understood. In this study, we apply improved protocols for sample preparation and recently-developed scanning microscopy techniques to visualize the ultrastructure of the C. neoformans capsule at high-resolution (up to 1 nm) and improved structural preservation. Although most capsule structures in nature consist of linear polymers, we show here that the C. neoformans capsule is a 'microgel-like' structure composed of branched polysaccharides. Moreover, we imaged the capsule-to-cell wall link, which is formed by thin fibers that branch out of thicker capsule filaments, and have one end firmly embedded in the cell wall structure. Together, our findings provide compelling ultrastructural evidence for a branched and complex capsule conformation, which may have important implications for the biological activity of the capsule as a virulence factor.
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Affiliation(s)
- Glauber R de S Araújo
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil
| | - Giselle N Fontes
- National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil
| | - Daniela Leão
- National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil
| | - Gustavo Miranda Rocha
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno Pontes
- Laboratório de Pinças Óticas - COPEA, Instituto de Ciências Biomédicas, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Celso Sant'Anna
- National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; National Institute of Metrology, Quality and Technology (Inmetro), Duque de Caxias, Rio de Janeiro, Brazil.
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92
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Kunduru BR, Nair SA, Rathinavelan T. EK3D: an E. coli K antigen 3-dimensional structure database. Nucleic Acids Res 2015; 44:D675-81. [PMID: 26615200 PMCID: PMC4702918 DOI: 10.1093/nar/gkv1313] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 11/10/2015] [Indexed: 12/24/2022] Open
Abstract
A very high rate of multidrug resistance (MDR) seen among Gram-negative bacteria such as Escherichia, Klebsiella, Salmonella, Shigella, etc. is a major threat to public health and safety. One of the major virulent determinants of Gram-negative bacteria is capsular polysaccharide or K antigen located on the bacterial outer membrane surface, which is a potential drug & vaccine target. It plays a key role in host–pathogen interactions as well as host immune evasion and thus, mandates detailed structural information. Nonetheless, acquiring structural information of K antigens is not straightforward due to their innate enormous conformational flexibility. Here, we have developed a manually curated database of K antigens corresponding to various E. coli serotypes, which differ from each other in their monosaccharide composition, linkage between the monosaccharides and their stereoisomeric forms. Subsequently, we have modeled their 3D structures and developed an organized repository, namely EK3D that can be accessed through www.iith.ac.in/EK3D/. Such a database would facilitate the development of antibacterial drugs to combat E. coli infections as it has evolved resistance against 2 major drugs namely, third-generation cephalosporins and fluoroquinolones. EK3D also enables the generation of polymeric K antigens of varying lengths and thus, provides comprehensive information about E. coli K antigens.
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Affiliation(s)
- Bharathi Reddy Kunduru
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State 502285, India
| | - Sanjana Anilkumar Nair
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State 502285, India
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93
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Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp. Sci Rep 2015; 5:15573. [PMID: 26493302 PMCID: PMC4616057 DOI: 10.1038/srep15573] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 09/28/2015] [Indexed: 11/15/2022] Open
Abstract
A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types. Accordingly, wzy-based capsular genotyping could differentiate capsule types except for those lacking wzy (K29 and K50), those sharing identical wzy (K22 vs. K37); and should be carefully applied in those exhibited high similarity (K12 vs. K41, K2 vs. K13, K74 vs. K80, K79 vs. KN1 and K30 vs. K69). Comparison of CPS structures in several capsular types that shared similarity in their gene contents implies possible functions of glycosyltransferases. Therefore, our results provide complete set of cps in various types of Klebsiella spp., which enable the understandings of relationship between genes and CPS structures and are useful for identification of documented or new capsular types.
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94
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Nguyen SH, Webb HK. Sensitive Detection of Deliquescent Bacterial Capsules through Nanomechanical Analysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11311-11317. [PMID: 26425936 DOI: 10.1021/acs.langmuir.5b02546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Encapsulated bacteria usually exhibit strong resistance to a wide range of sterilization methods, and are often virulent. Early detection of encapsulation can be crucial in microbial pathology. This work demonstrates a fast and sensitive method for the detection of encapsulated bacterial cells. Nanoindentation force measurements were used to confirm the presence of deliquescent bacterial capsules surrounding bacterial cells. Force/distance approach curves contained characteristic linear-nonlinear-linear domains, indicating cocompression of the capsular layer and cell, indentation of the capsule, and compression of the cell alone. This is a sensitive method for the detection and verification of the encapsulation status of bacterial cells. Given that this method was successful in detecting the nanomechanical properties of two different layers of cell material, i.e. distinguishing between the capsule and the remainder of the cell, further development may potentially lead to the ability to analyze even thinner cellular layers, e.g. lipid bilayers.
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Affiliation(s)
- Song Ha Nguyen
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , P.O. Box 218, Hawthorn 3122, Victoria, Australia
| | - Hayden K Webb
- Faculty of Science, Engineering and Technology, Swinburne University of Technology , P.O. Box 218, Hawthorn 3122, Victoria, Australia
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95
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Liu C, Zheng H, Yang M, Xu Z, Wang X, Wei L, Tang B, Liu F, Zhang Y, Ding Y, Tang X, Wu B, Johnson TJ, Chen H, Tan C. Genome analysis and in vivo virulence of porcine extraintestinal pathogenic Escherichia coli strain PCN033. BMC Genomics 2015; 16:717. [PMID: 26391348 PMCID: PMC4578781 DOI: 10.1186/s12864-015-1890-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 09/01/2015] [Indexed: 11/17/2022] Open
Abstract
Background Strains of extraintestinal pathogenic Escherichia coli (ExPEC) can invade and colonize extraintestinal sites and cause a wide range of infections. Genomic analysis of ExPEC has mainly focused on isolates of human and avian origins, with porcine ExPEC isolates yet to be sequenced. To better understand the genomic attributes underlying the pathogenicity of porcine ExPEC, we isolated two E. coli strains PCN033 and PCN061 from pigs, assessed their in vivo virulence, and completed and compared their genomes. Results Animal experiments demonstrated that strain PCN033, but not PCN061, was pathogenic in a pig model. The chromosome of PCN033 was 384 kb larger than that of PCN061. Among the PCN033-specific sequences, genes encoding adhesins, unique lipopolysaccharide, unique capsular polysaccharide, iron acquisition and transport systems, and metabolism were identified. Additionally, a large plasmid PCN033p3 harboring many typical ExPEC virulence factors was identified in PCN033. Based on the genetic variation between PCN033 and PCN061, corresponding phenotypic differences in flagellum-dependent swarming motility and metabolism were verified. Furthermore, the comparative genomic analyses showed that the PCN033 genome shared many similarities with genomic sequences of human ExPEC strains. Additionally, comparison of PCN033 genome with other nine characteristic E. coli genomes revealed 425 PCN033-special coding sequences. Genes of this subset included those encoding type I restriction-modification (R-M) system, type VI secretion system (T6SS) and membrane-associated proteins. Conclusions The genetic and phenotypic differences between PCN033 and PCN061 could partially explain their differences in virulence, and also provide insight towards the molecular mechanisms of porcine ExPEC infections. Additionally, the similarities between the genomes of PCN033 and human ExPEC strains suggest that some connections between porcine and human ExPEC strains exist. The first completed genomic sequence for porcine ExPEC and the genomic differences identified by comparative analyses provide a baseline understanding of porcine ExPEC genetics and lay the foundation for their further study. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1890-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Canying Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China. .,Department of Veterinary Medicine, Foshan University, Foshan, Guangdong, China.
| | - Huajun Zheng
- Shanghai-Most Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China.
| | - Minjun Yang
- Shanghai-Most Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China.
| | - Zhuofei Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Xiangru Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Liuya Wei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Biao Tang
- Shanghai-Most Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China. .,State Key Laboratory of Genetic Engineering, Department of Microbiology, School of Life Sciences, Fudan University, Shanghai, China.
| | - Feng Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Yanyan Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Yi Ding
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Xibiao Tang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Bin Wu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Timothy J Johnson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, Minnesota, USA.
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
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96
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Cyclic AMP (cAMP) Receptor Protein-cAMP Complex Regulates Heparosan Production in Escherichia coli Strain Nissle 1917. Appl Environ Microbiol 2015; 81:7687-96. [PMID: 26319872 DOI: 10.1128/aem.01814-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/20/2015] [Indexed: 11/20/2022] Open
Abstract
Heparosan serves as the starting carbon backbone for the chemoenzymatic synthesis of heparin, a widely used clinical anticoagulant drug. The availability of heparosan is a significant concern for the cost-effective synthesis of bioengineered heparin. The carbon source is known as the pivotal factor affecting heparosan production. However, the mechanism by which carbon sources control the biosynthesis of heparosan is unclear. In this study, we found that the biosynthesis of heparosan was influenced by different carbon sources. Glucose inhibits the biosynthesis of heparosan, while the addition of either fructose or mannose increases the yield of heparosan. Further study demonstrated that the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex binds to the upstream region of the region 3 promoter and stimulates the transcription of the gene cluster for heparosan biosynthesis. Site-directed mutagenesis of the CRP binding site abolished its capability of binding CRP and eliminated the stimulative effect on transcription. (1)H nuclear magnetic resonance (NMR) analysis was further performed to determine the Escherichia coli strain Nissle 1917 (EcN) heparosan structure and quantify extracellular heparosan production. Our results add to the understanding of the regulation of heparosan biosynthesis and may contribute to the study of other exopolysaccharide-producing strains.
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97
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Joensen KG, Tetzschner AMM, Iguchi A, Aarestrup FM, Scheutz F. Rapid and Easy In Silico Serotyping of Escherichia coli Isolates by Use of Whole-Genome Sequencing Data. J Clin Microbiol 2015; 53:2410-26. [PMID: 25972421 PMCID: PMC4508402 DOI: 10.1128/jcm.00008-15] [Citation(s) in RCA: 586] [Impact Index Per Article: 65.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/02/2015] [Indexed: 11/20/2022] Open
Abstract
Accurate and rapid typing of pathogens is essential for effective surveillance and outbreak detection. Conventional serotyping of Escherichia coli is a delicate, laborious, time-consuming, and expensive procedure. With whole-genome sequencing (WGS) becoming cheaper, it has vast potential in routine typing and surveillance. The aim of this study was to establish a valid and publicly available tool for WGS-based in silico serotyping of E. coli applicable for routine typing and surveillance. A FASTA database of specific O-antigen processing system genes for O typing and flagellin genes for H typing was created as a component of the publicly available Web tools hosted by the Center for Genomic Epidemiology (CGE) (www.genomicepidemiology.org). All E. coli isolates available with WGS data and conventional serotype information were subjected to WGS-based serotyping employing this specific SerotypeFinder CGE tool. SerotypeFinder was evaluated on 682 E. coli genomes, 108 of which were sequenced for this study, where both the whole genome and the serotype were available. In total, 601 and 509 isolates were included for O and H typing, respectively. The O-antigen genes wzx, wzy, wzm, and wzt and the flagellin genes fliC, flkA, fllA, flmA, and flnA were detected in 569 and 508 genome sequences, respectively. SerotypeFinder for WGS-based O and H typing predicted 560 of 569 O types and 504 of 508 H types, consistent with conventional serotyping. In combination with other available WGS typing tools, E. coli serotyping can be performed solely from WGS data, providing faster and cheaper typing than current routine procedures and making WGS typing a superior alternative to conventional typing strategies.
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Affiliation(s)
- Katrine G Joensen
- National Food Institute, Division for Epidemiology and Microbial Genomics, Technical University of Denmark, Kgs. Lyngby, Denmark WHO Collaborating Centre for Reference and Research on Escherichia and Klebsiella, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | - Anna M M Tetzschner
- WHO Collaborating Centre for Reference and Research on Escherichia and Klebsiella, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | - Atsushi Iguchi
- Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Frank M Aarestrup
- National Food Institute, Division for Epidemiology and Microbial Genomics, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Flemming Scheutz
- WHO Collaborating Centre for Reference and Research on Escherichia and Klebsiella, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
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98
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Pontes B, Frases S. The Cryptococcus neoformans capsule: lessons from the use of optical tweezers and other biophysical tools. Front Microbiol 2015; 6:640. [PMID: 26157436 PMCID: PMC4478440 DOI: 10.3389/fmicb.2015.00640] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/12/2015] [Indexed: 01/19/2023] Open
Abstract
The fungal pathogen Cryptococcus neoformans causes life-threatening infections in immunocompromised individuals, representing one of the leading causes of morbidity and mortality in AIDS patients. The main virulence factor of C. neoformans is the polysaccharide capsule; however, many fundamental aspects of capsule structure and function remain poorly understood. Recently, important capsule properties were uncovered using optical tweezers and other biophysical techniques, including dynamic and static light scattering, zeta potential and viscosity analysis. This review provides an overview of the latest findings in this emerging field, explaining the impact of these findings on our understanding of C. neoformans biology and resistance to host immune defenses.
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Affiliation(s)
- Bruno Pontes
- Laboratório de Pinças Óticas da Coordenação de Programas de Estudos Avançados, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
| | - Susana Frases
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil
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99
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Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine. Infect Immun 2015; 83:2605-13. [PMID: 25870229 PMCID: PMC4468546 DOI: 10.1128/iai.00188-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/03/2015] [Indexed: 11/20/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomal gfp reporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract.
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100
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Wong A, Lange D, Houle S, Arbatsky NP, Valvano MA, Knirel YA, Dozois CM, Creuzenet C. Role of capsular modified heptose in the virulence ofCampylobacter jejuni. Mol Microbiol 2015; 96:1136-58. [DOI: 10.1111/mmi.12995] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Anthony Wong
- Department of Microbiology and Immunology; Western University; DSB 3031 London ON N6A 5C1 Canada
| | - Dirk Lange
- Department of Microbiology and Immunology; Western University; DSB 3031 London ON N6A 5C1 Canada
| | | | - Nikolay P. Arbatsky
- N.D. Zelinsky Institute of Organic Chemistry; Russian Academy of Sciences; Moscow Russia
| | - Miguel A. Valvano
- Department of Microbiology and Immunology; Western University; DSB 3031 London ON N6A 5C1 Canada
- Centre for Infection and Immunity; Queen's University of Belfast; Belfast UK
| | - Yuriy A. Knirel
- N.D. Zelinsky Institute of Organic Chemistry; Russian Academy of Sciences; Moscow Russia
| | | | - Carole Creuzenet
- Department of Microbiology and Immunology; Western University; DSB 3031 London ON N6A 5C1 Canada
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