The oxacillinase variant, OXA-1152, in Pandoraea sputorum contributes to discrepancies in carbapenem resistance.

Pandoraea species are emerging multidrug-resistant pathogens with inconsistent carbapenem susceptibility, being resistant to meropenem but susceptible to imipenem, which complicates treatment. Here, we identified a previously uncharacterized oxacillinase gene, bla (OXA-1152), in 12 Pandoraea sputorum strains from Wuhan, China. Deleting bla (OXA-1152) reduced meropenem and imipenem minimal inhibitory concentrations (MICs) by 64- and 4-fold, respectively, while reintroducing it into P. sputorum and E. coli DH5α restored resistance. Mechanistically, OXA-1152 exhibited stronger binding and hydrolysis efficiency for meropenem than imipenem. Combining avibactam with carbapenems restored susceptibility to meropenem and further reduced imipenem MICs, highlighting OXA-1152's role in resistance variation. These findings reveal the molecular basis of carbapenem resistance discrepancy in Pandoraea and suggest avibactam-carbapenem combinations as a promising therapeutic strategy, offering broader implications for treating multidrug-resistant infections.