Poster Presentation MedVetPATHOGENS 2018

Novel multiresistance integrative and conjugative element ICEPmu2 from a German bovine Pasteurella multocida isolate (#113)

Kristina Kadlec 1 , Jun Li 2 , Geovana B Michael 3 , Heike Kaspar 4 , Yingbo Shen 2 , Yang Wang 2 , Stefan Schwarz 3
  1. Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt-Mariensee, Germany
  2. Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
  3. Institute of Microbiology and Epizootics, Freie Universität Berlin, Berlin, Germany
  4. Federal Office of Consumer Protection and Food Safety (BVL), Berlin, Germany

Background and objectives: In North America, multiresistant Pasteurellaceae harboring integrative and conjugative elements (ICEs) - such as ICEPmu1 which carries twelve resistance genes and confers resistance to eight classes of antimicrobial agents - are widespread. The aim of this study was to identify the antimicrobial resistance genes in a multiresistant Pasteurella multocida isolate and to investigate their location on mobile genetic elements.

Materials and methods: P. multocida isolates (n=375) originating from the German national resistance monitoring program GERM-Vet (2004-2010) were investigated by antimicrobial susceptibility testing. A single multiresistant isolate from 2010 that exhibited resistance to chloramphenicol, tetracycline, tilmicosin, sulfonamides and streptomycin was identified. The plasmid content was checked by plasmid extraction via alkaline lysis. Whole genome sequencing was performed to identify the resistance genes and to analyse their genetic environment.

Results: Whole genome analysis revealed the presence of an integrative and conjugative element (ICE), designated ICEPmu2. No plasmid was detectable. ICEPmu2 has a size of 51,121 bp and a GC content of 41%. It harbors 133 open reading frames for proteins with sizes of >75 amino acids. The chromosomal integration site and the core genome of ICEPmu2 were virtually the same as in ICEPmu1. However, only a single resistance gene region was present in ICEPmu2, which includes the resistance genes sul2 (sulfonamide resistance), catA3 (chloramphenicol resistance), strA and strB (streptomycin resistance), all located in the same orientation. In addition, ICEPmu2 conferred also tetracycline resistance via the gene tet(Y), which was located downstream of the sul2-catA3-strA-strB resistance gene cluster. This tetracycline resistance gene was identified for the first time in P. multocida.

Conclusion: The identification of an ICE conferring multiresistance in a Pasteurella isolate from Germany is alarming. While widespread in North America, such multiresistant bovine respiratory tract pathogens have been rarely detected in Germany or other European countries.