PER extended-spectrum β-lactamases originate from Pararheinheimera spp.

Highlights • bla PER extended-spectrum β-lactamase genes were mobilised from Pararheinheimera spp. • A Pararheinheimera branch acquired the bla PER progenitor long ago. • Mobilisation of bla PER genes into pathogens is a recent event. ABSTRACT To investigate the origin of PER extended-spectrum β-lactamases, publicly available sequence databases were searched for bla PER-like genes. Three genomes from Pararheinheimera , a genus associated with water and soil environments, were found to carry bla PER-like genes but lacked the IS CR1 /IS Pa12 /IS Pa13 insertion sequences commonly associated with bla PER in clinical isolates. Sequence analysis revealed 78–96% nucleotide identity and conserved synteny between the clinical mobile genetic elements (MGEs) encoding bla PER-1 and the bla PER locus in the Pararheinheimera genomes. Notably, bla PER genes were only identified in 3 of 21 Pararheinheimera and Rheinheimera genomes, whereas the genetic environment of bla PER genes as found in clinical MGEs was conserved in all Pararheinheimera and Rheinheimera genomes. These findings indicate that bla PER genes were likely acquired by a branch of the Pararheinheimera genus long before the antibiotic era. Later, bla PER genes were mobilised, likely through the involvement of insertion sequences, from one or several Pararheinheimera species, allowing their dissemination into human pathogens. [ABSTRACT FROM AUTHOR]