title: ICEApl1, an Integrative Conjugative Element Related to ICEHin1056, Identified in the Pig Pathogen Actinobacillus pleuropneumoniae.
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.
authors.affiliation: Section of Paediatrics, Department of Medicine, Imperial College London London, UK.
authors.forename: Janine T
authors.initials: JT
authors.lastname: Bossé
authors.affiliation: Section of Paediatrics, Department of Medicine, Imperial College London London, UK.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Li
authors.affiliation: Section of Paediatrics, Department of Medicine, Imperial College London London, UK.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernandez Crespo
authors.affiliation: Department of Veterinary Medicine, University of Cambridge Cambridge, UK.
authors.forename: Roy R
authors.initials: RR
authors.lastname: Chaudhuri
authors.affiliation: Animal and Plant Health Agency Bury St Edmunds Suffolk, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Rogers
authors.affiliation: The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton Cambridge, UK.
authors.forename: Matthew T G
authors.initials: MT
authors.lastname: Holden
authors.affiliation: Department of Veterinary Medicine, University of Cambridge Cambridge, UK.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Maskell
authors.affiliation: Department of Veterinary Medicine, University of Cambridge Cambridge, UK.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Tucker
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine London, UK.
authors.forename: Brendan W
authors.initials: BW
authors.lastname: Wren
authors.affiliation: Department of Pathology and Pathogen Biology, The Royal Veterinary College Hatfield, UK.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Rycroft
authors.affiliation: Section of Paediatrics, Department of Medicine, Imperial College London London, UK.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Langford
keywords: Pasteurellaceae; animal infections; antibiotic resistance; conjugation; respiratory tract