Emerging of bla NDM-5 in Providencia rettgeri and Morganella morganii from Brazilian Clinical Isolates

The genus Providencia and Morganella are part of the World Health Organization (WHO) critical priority pathogens when carbapenem-resistant. This study characterized the molecular epidemiology of carbapenemase genes in 13 clinical isolates of carbapenem-resistant Providencia spp. and Morganella morganii from a Brazilian tertiary hospital. Following species confirmation by MALDI-TOF MS, one of the isolates was reclassified as M. morganii . PCR and amplicon sequencing screened for bla KPC , bla NDM , bla VIM , bla IMP , bla GES , and bla OXA-23 , −24 , −48-LIKE , −51 , −58 , −143 . The bla NDM (11/13, 84.6%) and bla KPC (4/13, 30.8%) were the only carbapenemase genes detected. All isolates tested negative for bla VIM , bla IMP , bla GES , and OXA-type genes. bla NDM-5 was identified in one P. rettgeri and one M. morganii (first reports in Brazil). bla KPC-2 / bla NDM-1 co-occurrence was documented in two P. stuartii isolates. Clinical analysis of bla NDM-5 carriers revealed severe outcomes: one patient self-discharged without targeted therapy, and another died following amputation, extensive antimicrobial exposure, and COVID-19 co-infection. The accumulation of co-expressed resistance mechanisms highlights Providencia spp. and M. morganii as emerging therapeutic challenges.