Clinical emergence of Providencia zhejiangensis sp. nov. and Providencia xihuensis sp. nov.: Genomic insights into antimicrobial resistance and geographical distribution.

Members of the genus Providencia are typically opportunistic pathogens that can cause severe infections in immunocompromised hosts. This study identified two Providencia strains, SKLX146130 and SKLX074055, representing novel species designated as Providencia zhejiangensis sp. nov. and Providencia xihuensis sp. nov., respectively. Both strains were isolated from clinical samples, with P. zhejiangensis displaying extensive drug resistance. Our analysis revealed that P. xihuensis is predominantly from China, whereas P. zhejiangensis has a global presence. Meanwhile, our analyses resolved Providencia huashanensis as a later heterotypic synonym of Providencia xianensis. Notably, the strain SKLX146130 from P. zhejiangensis, characterized by carrying multiple acquired resistance determinants including the carbapenemase gene blaNDM-1, belongs to a zoonotic subclade. The genomic analyses of the P. zhejiangensis strain SKLX146130 and Providencia xihuensis strain SKLX074055 showed 79.76-84.55% and 79.85-95.85% average nucleotide identity (ANI), respectively, with other Providencia type strains. In silico DNA-DNA hybridization (dDDH) values ranged from 20.7 to 26.2% and 21.3-64.8%, respectively. These results, along with phenotypic characterization and phylogenetic evidence, confirm that SKLX146130 and SKLX074055 represent two distinct novel species within the genus Providencia. Consequently, we propose the names Providencia zhejiangensis sp. nov. and Providencia xihuensis sp. nov. for these species and call for monitoring these species in clinical infections.