Molecular epidemiology of global carbapenemase-producing Serratia spp. (2015-2017)

Limited information is available regarding the global molecular epidemiology of Serratia spp. with carbapenemases. We characterized carbapenemase-producing Serratia spp. (n = 56) using short read whole genome sequencing (WGS) obtained from global surveillance programs (2015-17). KPC (54%), VIM (16%) and NDM (14%) were the most common carbapenemases, followed by OXA-48 (10%), IMP-8 (four %), GES-5 (two %). The population was heterogenous, consisting of seven species and thirty-two clones. Serratia sarumanii (32%), Serratia nevei (23%), Serratia marcescens sensu stricto (20%) were the principal species. S. sarumanii contained three dominant clones: ST795 with bla_VIM-1 from Italy; ST256 with bla_KPC-3 from USA; ST428 with bla_KPC-2 from Colombia and China. S. nevei contained two dominant clones: ST893 with various carbapenemases from South Africa; ST325 with bla_KPC-2 from Colombia, and with bla_IMP-8 from Taiwan. Class I integrons (In916 with bla_VIM-1, In238 with bla_VIM-4 and In73 with bla_IMP-8) circulated between various Enterobacterales species and clones in Europe and Taiwan. Carbapenemase-producing Serratia spp. disseminated either clonally and polyclonally, depending on the species, clones and geographical location. Whole genome sequencing offered unprecedented details about global carbapenemase-producing Enterobacterales species obtained from the same surveillance programs over similar time periods. This work also highlights the need to address the taxonomy of Serratia spp. since confusion currently exists regarding species and sub-species within this genus.