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Saiz-Escobedo L, Cadenas-Jiménez I, Olmos R, Carrera-Salinas A, Berbel D, Càmara J, Tubau F, Domínguez MA, Ardanuy C, González-Díaz A, Marti S. Detection of bla CTX-M-15 in an integrative and conjugative element in four extensively drug-resistant Haemophilus parainfluenzae strains causing urethritis. Int J Antimicrob Agents 2023; 62:106991. [PMID: 37774891 DOI: 10.1016/j.ijantimicag.2023.106991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/12/2023] [Accepted: 09/21/2023] [Indexed: 10/01/2023]
Abstract
Haemophilus parainfluenzae is a commensal organism with rising numbers of multidrug-resistant (MDR) strains. This pathogen is of increasing clinical relevance in urogenital infection. The aim of this work was to identify and characterise the molecular mechanisms of resistance associated with four cephalosporin-resistant H. parainfluenzae strains collected from patients with urethritis. Antimicrobial resistance was determined by microdilution following European Committee on Antimicrobial Susceptibility Testing criteria. Strains were then analysed by whole-genome sequencing to determine clonal relationship and the molecular basis of antimicrobial resistance. Finally, a phylogenetic analysis was performed on all urogenital MDR strains of H. parainfluenzae previously isolated in our hospital. All strains were resistant to β-lactams, macrolides, tetracycline, fluoroquinolones, chloramphenicol, cotrimoxazole, and aminoglycosides. The resistance profile was compatible with the presence of an extended-spectrum β-lactamase (ESBL). Whole-genome sequencing detected blaCTX-M-15 that conferred high minimum inhibitory concentrations to cephalosporins in two novel integrative and conjugative elements (ICEHpaHUB6 and ICEHpaHUB7) that also harboured a blaTEM-1 β-lactamase. This study shows a novel blaCTX-M-15 ESBL carried in an integrative conjugative element in four extensively drug-resistant H. parainfluenzae strains. This resistance determinant could be transmitted to other sexually transmitted pathogens and this is a cause for concern.
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Affiliation(s)
- L Saiz-Escobedo
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain
| | - I Cadenas-Jiménez
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - R Olmos
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain
| | - A Carrera-Salinas
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain
| | - D Berbel
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - J Càmara
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - F Tubau
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - M A Domínguez
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Infectious Diseases (CIBERINFEC), ISCIII, Madrid, Spain; Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - C Ardanuy
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain; Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - A González-Díaz
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
| | - S Marti
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL-UB, Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain; Department of Medicine, School of Medicine, University of Barcelona, Barcelona, Spain.
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2
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Colombi E, Perry BJ, Sullivan JT, Bekuma AA, Terpolilli JJ, Ronson CW, Ramsay JP. Comparative analysis of integrative and conjugative mobile genetic elements in the genus Mesorhizobium. Microb Genom 2021; 7. [PMID: 34605762 PMCID: PMC8627217 DOI: 10.1099/mgen.0.000657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Members of the Mesorhizobium genus are soil bacteria that often form nitrogen-fixing symbioses with legumes. Most characterised Mesorhizobium spp. genomes are ~8 Mb in size and harbour extensive pangenomes including large integrative and conjugative elements (ICEs) carrying genes required for symbiosis (ICESyms). Here, we document and compare the conjugative mobilome of 41 complete Mesorhizobium genomes. We delineated 56 ICEs and 24 integrative and mobilizable elements (IMEs) collectively occupying 16 distinct integration sites, along with 24 plasmids. We also demonstrated horizontal transfer of the largest (853,775 bp) documented ICE, the tripartite ICEMspSymAA22. The conjugation systems of all identified ICEs and several plasmids were related to those of the paradigm ICESym ICEMlSymR7A, with each carrying conserved genes for conjugative pilus formation (trb), excision (rdfS), DNA transfer (rlxS) and regulation (fseA). ICESyms have likely evolved from a common ancestor, despite occupying a variety of distinct integration sites and specifying symbiosis with diverse legumes. We found extensive evidence for recombination between ICEs and particularly ICESyms, which all uniquely lack the conjugation entry-exclusion factor gene trbK. Frequent duplication, replacement and pseudogenization of genes for quorum-sensing-mediated activation and antiactivation of ICE transfer suggests ICE transfer regulation is constantly evolving. Pangenome-wide association analysis of the ICE identified genes potentially involved in symbiosis, rhizosphere colonisation and/or adaptation to distinct legume hosts. In summary, the Mesorhizobium genus has accumulated a large and dynamic pangenome that evolves through ongoing horizontal gene transfer of large conjugative elements related to ICEMlSymR7A.
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Affiliation(s)
- Elena Colombi
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,Curtin Medical School, Curtin University, Perth, WA, Australia
| | - Benjamin J Perry
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - John T Sullivan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Amanuel A Bekuma
- Centre for Rhizobium Studies, Food Futures Institute, Murdoch University, Perth, WA, Australia, Murdoch University, Perth, WA, Australia.,Present address: Western Australian Department of Primary Industries and Regional Development, Research and Industry Innovation, South Perth, WA, Australia
| | - Jason J Terpolilli
- Centre for Rhizobium Studies, Food Futures Institute, Murdoch University, Perth, WA, Australia, Murdoch University, Perth, WA, Australia
| | - Clive W Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Joshua P Ramsay
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.,Curtin Medical School, Curtin University, Perth, WA, Australia
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3
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Sierra Y, González-Díaz A, Carrera-Salinas A, Berbel D, Vázquez-Sánchez DA, Tubau F, Cubero M, Garmendia J, Càmara J, Ayats J, Ardanuy C, Marti S. Genome-wide analysis of urogenital and respiratory multidrug-resistant Haemophilus parainfluenzae. J Antimicrob Chemother 2021; 76:1741-1751. [PMID: 33792695 DOI: 10.1093/jac/dkab109] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 03/02/2021] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To characterize the mechanisms of antimicrobial resistance and the prevalence of the polysaccharide capsule among urogenital and respiratory Haemophilus parainfluenzae isolates. METHODS Antimicrobial susceptibility was tested by microdilution. Fifty-five MDR strains were subjected to WGS and were phylogenetically compared with all the available H. parainfluenzae genomes from the NCBI database. The identification of the capsular bexA gene was performed by PCR in 266 non-MDR strains. RESULTS In 31 of the 42 ampicillin-resistant strains, blaTEM-1 located within Tn3 was identified. β-Lactamase-negative cefuroxime-resistant strains (n = 12) presented PBP3 substitutions. The catS gene (n = 14), the tet(M)-MEGA element (n = 18) and FolA substitutions (I95L and F154V/S) (n = 41) were associated with resistance to chloramphenicol, tetracycline plus macrolides, and co-trimoxazole, respectively. Thirty-seven isolates had a Tn10 harbouring tet(B)/(C)/(D)/(R) genes with (n = 15) or without (n = 22) catA2. Putative transposons (Tn7076-Tn7079), including aminoglycoside and co-trimoxazole resistance genes, were identified in 10 strains (18.2%). These transposons were integrated into three new integrative and conjugative elements (ICEs), which also included the resistance-associated transposons Tn3 and Tn10. The capsular operon was found only in the urogenital isolates (18/154, 11.7%), but no phylogenetic clustering was observed. The capsular operons identified were similar to those of Haemophilus influenzae serotype c and Haemophilus sputorum type 2. CONCLUSIONS The identification of ICEs with up to three resistance-associated transposons suggests that these transferable elements play an important role in the acquisition of multidrug resistance in H. parainfluenzae. Moreover, the presence of polysaccharide capsules in some of these urogenital isolates is a cause for concern.
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Affiliation(s)
- Yanik Sierra
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain
| | - Aida González-Díaz
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Anna Carrera-Salinas
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain
| | - Dàmaris Berbel
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Daniel Antonio Vázquez-Sánchez
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Spanish Network for Research in Infectious Diseases (REIPI), ISCIII, Madrid, Spain
| | - Fe Tubau
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Meritxell Cubero
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Junkal Garmendia
- Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Instituto de Agrobiotecnología, CSIC-Gobierno Navarra, Mutilva, Spain
| | - Jordi Càmara
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Josefina Ayats
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain
| | - Carmen Ardanuy
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Sara Marti
- Microbiology Department, Hospital Universitari de Bellvitge, IDIBELL, Barcelona, Spain.,Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.,Department of Medicine, School of Medicine, University of Barcelona, Barcelona, Spain
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4
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Beker M, Rose S, Lykkebo CA, Douthwaite S. Integrative and Conjugative Elements (ICEs) in Pasteurellaceae Species and Their Detection by Multiplex PCR. Front Microbiol 2018; 9:1329. [PMID: 29997583 PMCID: PMC6028734 DOI: 10.3389/fmicb.2018.01329] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/30/2018] [Indexed: 11/13/2022] Open
Abstract
Strains of the Pasteurellaceae bacteria Pasteurella multocida and Mannheimia haemolytica are major etiological agents of bovine respiratory disease (BRD). Treatment of BRD with antimicrobials is becoming more challenging due to the increasing occurrence of resistance in infecting strains. In Pasteurellaceae strains exhibiting resistance to multiple antimicrobials including aminoglycosides, beta-lactams, macrolides and sulfonamides, the resistance determinants are often chromosomally encoded within integrative and conjugative elements (ICEs). To gain a more comprehensive picture of ICE structures, we sequenced the genomes of six strains of P. multocida and four strains of M. haemolytica; all strains were independent isolates and eight of them were multiple-resistant. ICE sequences varied in size from 49 to 79 kb, and were comprised of an array of conserved genes within a core region and varieties of resistance genes within accessory regions. These latter regions mainly account for the variation in the overall ICE sizes. From the sequence data, we developed a multiplex PCR assay targeting four conserved core genes required for integration and maintenance of ICE structures. Application of this assay on 75 isolates of P. multocida and M. haemolytica reveals how the presence and structures of ICEs are related to their antibiotic resistance phenotypes. The assay is also applicable to other members of the Pasteurellaceae family including Histophilus somni and indicates how clustering and dissemination of the resistance genes came about.
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Affiliation(s)
- Michal Beker
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Simon Rose
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Claus A Lykkebo
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Stephen Douthwaite
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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5
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Abotsi RE, Govinden U, Essack SY. Mechanisms of antibiotic resistance in Haemophilus parainfluenzae. S Afr J Infect Dis 2017. [DOI: 10.1080/23120053.2017.1320853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Regina E. Abotsi
- Antimicrobial Research Unit, School of Health Science, University of KwaZulu Natal, Durban, South Africa
- School of Pharmacy, University of Health and Allied Sciences, Ho, Ghana
| | - Usha Govinden
- Antimicrobial Research Unit, School of Health Science, University of KwaZulu Natal, Durban, South Africa
| | - Sabiha Y. Essack
- Antimicrobial Research Unit, School of Health Science, University of KwaZulu Natal, Durban, South Africa
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6
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Colombi E, Straub C, Künzel S, Templeton MD, McCann HC, Rainey PB. Evolution of copper resistance in the kiwifruit pathogenPseudomonas syringaepv.actinidiaethrough acquisition of integrative conjugative elements and plasmids. Environ Microbiol 2017; 19:819-832. [DOI: 10.1111/1462-2920.13662] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/02/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Elena Colombi
- New Zealand Institute for Advanced Study, Massey University; Auckland New Zealand
| | - Christina Straub
- New Zealand Institute for Advanced Study, Massey University; Auckland New Zealand
| | - Sven Künzel
- Max Planck Institute for Evolutionary Biology; Plön Germany
| | - Matthew D. Templeton
- Plant and Food Research; Auckland New Zealand
- School of Biological Sciences; University of Auckland; Auckland New Zealand
| | - Honour C. McCann
- New Zealand Institute for Advanced Study, Massey University; Auckland New Zealand
- South China Botanical Institute; Chinese Academy of Sciences; Guangzhou China
| | - Paul B. Rainey
- New Zealand Institute for Advanced Study, Massey University; Auckland New Zealand
- Max Planck Institute for Evolutionary Biology; Plön Germany
- Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris-Tech), PSL Research University; Paris France
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7
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Bossé JT, Li Y, Fernandez Crespo R, Chaudhuri RR, Rogers J, Holden MTG, Maskell DJ, Tucker AW, Wren BW, Rycroft AN, Langford PR. ICEApl1, an Integrative Conjugative Element Related to ICEHin1056, Identified in the Pig Pathogen Actinobacillus pleuropneumoniae. Front Microbiol 2016; 7:810. [PMID: 27379024 PMCID: PMC4908127 DOI: 10.3389/fmicb.2016.00810] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/12/2016] [Indexed: 12/26/2022] Open
Abstract
ICEApl1 was identified in the whole genome sequence of MIDG2331, a tetracycline-resistant (MIC = 8 mg/L) serovar 8 clinical isolate of Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia. PCR amplification of virB4, one of the core genes involved in conjugation, was used to identify other A. pleuropneumoniae isolates potentially carrying ICEApl1. MICs for tetracycline were determined for virB4 positive isolates, and shotgun whole genome sequence analysis was used to confirm presence of the complete ICEApl1. The sequence of ICEApl1 is 56083 bp long and contains 67 genes including a Tn10 element encoding tetracycline resistance. Comparative sequence analysis was performed with similar integrative conjugative elements (ICEs) found in other members of the Pasteurellaceae. ICEApl1 is most similar to the 59393 bp ICEHin1056, from Haemophilus influenzae strain 1056. Although initially identified only in serovar 8 isolates of A. pleuropneumoniae (31 from the UK and 1 from Cyprus), conjugal transfer of ICEApl1 to representative isolates of other serovars was confirmed. All isolates carrying ICEApl1 had a MIC for tetracycline of 8 mg/L. This is, to our knowledge, the first description of an ICE in A. pleuropneumoniae, and the first report of a member of the ICEHin1056 subfamily in a non-human pathogen. ICEApl1 confers resistance to tetracycline, currently one of the more commonly used antibiotics for treatment and control of porcine pleuropneumonia.
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Affiliation(s)
- Janine T Bossé
- Section of Paediatrics, Department of Medicine, Imperial College London London, UK
| | - Yanwen Li
- Section of Paediatrics, Department of Medicine, Imperial College London London, UK
| | | | - Roy R Chaudhuri
- Department of Veterinary Medicine, University of Cambridge Cambridge, UK
| | - Jon Rogers
- Animal and Plant Health Agency Bury St Edmunds Suffolk, UK
| | - Matthew T G Holden
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton Cambridge, UK
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge Cambridge, UK
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge Cambridge, UK
| | - Brendan W Wren
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK
| | - Andrew N Rycroft
- Department of Pathology and Pathogen Biology, The Royal Veterinary College Hatfield, UK
| | - Paul R Langford
- Section of Paediatrics, Department of Medicine, Imperial College London London, UK
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8
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Juhas M. Type IV secretion systems and genomic islands-mediated horizontal gene transfer in Pseudomonas and Haemophilus. Microbiol Res 2014; 170:10-7. [PMID: 25183653 DOI: 10.1016/j.micres.2014.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/28/2014] [Accepted: 06/30/2014] [Indexed: 11/16/2022]
Abstract
Bacterial secretion systems, such as type IV secretion systems (T4SSs) are multi-subunit machines transferring macromolecules across membranes. Besides proteins, T4SSs also transfer nucleoprotein complexes, thus having a significant impact on the evolution of bacterial species. By T4SS-mediated horizontal gene transfer bacteria can acquire a broad spectrum of fitness genes allowing them to thrive in the wide variety of environments. Furthermore, acquisition of antibiotic-resistance and virulence genes can lead to the emergence of novel 'superbugs'. This review provides an update on the investigation of T4SSs. It highlights the role T4SSs play in the horizontal gene transfer, particularly in the evolution of catabolic pathways, antibiotic-resistance and virulence in Haemophilus and Pseudomonas.
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Affiliation(s)
- Mario Juhas
- Department of Pathology, University of Cambridge, Tennis Court Road, CB2 1QP Cambridge, UK.
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9
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Tristram SG, Franks LR, Harvey GL. Sequences of small blaTEM-encoding plasmids in Haemophilus influenzae and description of variants falsely negative for blaTEM by PCR. J Antimicrob Chemother 2012; 67:2621-5. [PMID: 22782486 DOI: 10.1093/jac/dks264] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To characterize an unidentified β-lactamase and associated genetic background in a bla(TEM) and bla(ROB) PCR-negative Haemophilus influenzae isolate, and characterize small bla(TEM)-encoding plasmids in a collection of H. influenzae. METHODS The unidentified β-lactamase gene was identified by cloning and sequencing the encoding plasmid. Strains with small bla(TEM) plasmids were identified using negative PCR for integrative conjugative elements, but positive bla(TEM) PCR; plasmids from selected isolates were sequenced. PCR for rep and divergent bla(TEM) were evaluated for detecting small plasmids on selected H. influenzae isolates. RESULTS Small plasmids (4.8-5.5 kb) encoding bla(TEM) appear to be associated with remnants of Tn2 on a conserved plasmid core. The unidentified β-lactamase was actually a TEM-1, with negative bla(TEM) PCR associated with a previously unrecognized deletion of bp 1-27 of bla(TEM) (Sutcliffe numbering) associated with a larger deletion within Tn2. This deletion was found in other isolates and may be more common than previously thought. PCR for the conserved rep gene appears useful for screening for small bla(TEM)-encoding plasmids or associated cryptic plasmids in H. influenzae. CONCLUSIONS Small bla(TEM)-encoding plasmids in H. influenzae appear relatively conserved, but require further study to confirm this. PCR associated with the rep gene may be useful for studying these small plasmids. A deletion in part of bla(TEM) in some strains may interfere with some PCRs; therefore, care should be taken with primer selection or design and, preferably, regions within the open reading frame should be targeted.
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Affiliation(s)
- Stephen G Tristram
- School of Human Life Sciences, University of Tasmania, Launceston, Tasmania, Australia.
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10
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Zola TA, Lysenko ES, Weiser JN. Mucosal clearance of capsule-expressing bacteria requires both TLR and nucleotide-binding oligomerization domain 1 signaling. THE JOURNAL OF IMMUNOLOGY 2008; 181:7909-16. [PMID: 19017981 DOI: 10.4049/jimmunol.181.11.7909] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Expression of capsular polysaccharide by bacterial pathogens is associated with increased resistance to host clearance mechanisms, in particular by evading opsonization and uptake by professional phagocytes. The potential for rapid progression of disease caused by encapsulated bacteria points to the importance of innate immunity at the mucosal surface where infection is initiated. Using a murine model of nasopharyngeal colonization, host immune components that contribute to the mucosal clearance of capsule-expressing bacteria were investigated. Clearance of encapsulated Haemophilus influenzae (Hi) required both TLR and nucleotide-binding oligomerization domain (NOD) signaling pathways, whereas individual deficiencies in each of these signaling cascades did not affect clearance of nonencapsulated strains. Moreover, clearance of Hi-expressing capsular polysaccharide required the recruitment of neutrophils to the site of infection, and ex vivo phagocytic bacterial killing required expression of the NOD1 signaling pathway. Conversely, redundancies within these innate immune pathways of non-neutrophil cells were sufficient to promote mucosal clearance of nonencapsulated Hi. Our findings reveal a role for NOD1 in protection from encapsulated pathogens. In addition, this study provides an example of a microbial virulence determinant that alters the requirements for host signaling to provide effective protection.
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Affiliation(s)
- Tracey A Zola
- Department of Microbiology, University of Pennsylvania,Philadelphia, PA 19104, USA
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11
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Juhas M, van der Meer JR, Gaillard M, Harding RM, Hood DW, Crook DW. Genomic islands: tools of bacterial horizontal gene transfer and evolution. FEMS Microbiol Rev 2008; 33:376-93. [PMID: 19178566 PMCID: PMC2704930 DOI: 10.1111/j.1574-6976.2008.00136.x] [Citation(s) in RCA: 578] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bacterial genomes evolve through mutations, rearrangements or horizontal gene transfer. Besides the core genes encoding essential metabolic functions, bacterial genomes also harbour a number of accessory genes acquired by horizontal gene transfer that might be beneficial under certain environmental conditions. The horizontal gene transfer contributes to the diversification and adaptation of microorganisms, thus having an impact on the genome plasticity. A significant part of the horizontal gene transfer is or has been facilitated by genomic islands (GEIs). GEIs are discrete DNA segments, some of which are mobile and others which are not, or are no longer mobile, which differ among closely related strains. A number of GEIs are capable of integration into the chromosome of the host, excision, and transfer to a new host by transformation, conjugation or transduction. GEIs play a crucial role in the evolution of a broad spectrum of bacteria as they are involved in the dissemination of variable genes, including antibiotic resistance and virulence genes leading to generation of hospital ‘superbugs’, as well as catabolic genes leading to formation of new metabolic pathways. Depending on the composition of gene modules, the same type of GEIs can promote survival of pathogenic as well as environmental bacteria.
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Affiliation(s)
- Mario Juhas
- Clinical Microbiology and Infectious Diseases, Nuffield Department of Clinical Laboratory Sciences, University of Oxford, Oxford, UK.
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12
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Juhas M, Power PM, Harding RM, Ferguson DJP, Dimopoulou ID, Elamin ARE, Mohd-Zain Z, Hood DW, Adegbola R, Erwin A, Smith A, Munson RS, Harrison A, Mansfield L, Bentley S, Crook DW. Sequence and functional analyses of Haemophilus spp. genomic islands. Genome Biol 2008; 8:R237. [PMID: 17996041 PMCID: PMC2258188 DOI: 10.1186/gb-2007-8-11-r237] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 09/14/2007] [Accepted: 11/08/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A major part of horizontal gene transfer that contributes to the diversification and adaptation of bacteria is facilitated by genomic islands. The evolution of these islands is poorly understood. Some progress was made with the identification of a set of phylogenetically related genomic islands among the Proteobacteria, recognized from the investigation of the evolutionary origins of a Haemophilus influenzae antibiotic resistance island, namely ICEHin1056. More clarity comes from this comparative analysis of seven complete sequences of the ICEHin1056 genomic island subfamily. RESULTS These genomic islands have core and accessory genes in approximately equal proportion, with none demonstrating recent acquisition from other islands. The number of variable sites within core genes is similar to that found in the host bacteria. Furthermore, the GC content of the core genes is similar to that of the host bacteria (38% to 40%). Most of the core gene content is formed by the syntenic type IV secretion system dependent conjugative module and replicative module. GC content and lack of variable sites indicate that the antibiotic resistance genes were acquired relatively recently. An analysis of conjugation efficiency and antibiotic susceptibility demonstrates that phenotypic expression of genomic island-borne genes differs between different hosts. CONCLUSION Genomic islands of the ICEHin1056 subfamily have a longstanding relationship with H. influenzae and H. parainfluenzae and are co-evolving as semi-autonomous genomes within the 'supragenomes' of their host species. They have promoted bacterial diversity and adaptation through becoming efficient vectors of antibiotic resistance by the recent acquisition of antibiotic resistance transposons.
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Affiliation(s)
- Mario Juhas
- Clinical Microbiology and Infectious Diseases, NDCLS, University of Oxford, Headley Way, Oxford OX3 9DU, UK.
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Chung A, Perera R, Brueggemann AB, Elamin AE, Harnden A, Mayon-White R, Smith S, Crook DW, Mant D. Effect of antibiotic prescribing on antibiotic resistance in individual children in primary care: prospective cohort study. BMJ 2007; 335:429. [PMID: 17656505 PMCID: PMC1962897 DOI: 10.1136/bmj.39274.647465.be] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the effect of community prescribing of an antibiotic for acute respiratory infection on the prevalence of antibiotic resistant bacteria in an individual child. STUDY DESIGN Observational cohort study with follow-up at two and 12 weeks. SETTING General practices in Oxfordshire. PARTICIPANTS 119 children with acute respiratory tract infection, of whom 71 received a beta lactam antibiotic. MAIN OUTCOME MEASURES Antibiotic resistance was assessed by the geometric mean minimum inhibitory concentration (MIC) for ampicillin and presence of the ICEHin1056 resistance element in up to four isolates of Haemophilus species recovered from throat swabs at recruitment, two weeks, and 12 weeks. RESULTS Prescribing amoxicillin to a child in general practice more than triples the mean minimum inhibitory concentration for ampicillin (9.2 microg/ml v 2.7 microg/ml, P=0.005) and doubles the risk of isolation of Haemophilus isolates possessing homologues of ICEHin1056 (67% v 36%; relative risk 1.9, 95% confidence interval 1.2 to 2.9) two weeks later. Although this increase is transient (by 12 weeks ampicillin resistance had fallen close to baseline), it is in the context of recovery of the element from 35% of children with Haemophilus isolates at recruitment and from 83% (76% to 89%) at some point in the study. CONCLUSION The short term effect of amoxicillin prescribed in primary care is transitory in the individual child but sufficient to sustain a high level of antibiotic resistance in the population.
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Affiliation(s)
- Angela Chung
- Department of Primary Health Care, NIHR School of Primary Care Research, University of Oxford, Oxford OX3 7LF
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