Acinetobacter baumannii IC2 and IC5 Isolates with Co-Existing bla OXA-143-like and bla OXA-72 and Exhibiting Strong Biofilm Formation in a Mexican Hospital.

is an opportunistic pathogen responsible for healthcare-associated infections (HAIs) and outbreaks. Antimicrobial resistance mechanisms and virulence factors allow it to survive and spread in the hospital environment. However, the molecular mechanisms of these traits and their association with international clones are frequently unknown in low- and middle-income countries. Here, we analyze the phenotype and genotype of seventy-six HAIs and outbreak-causing isolates from a Mexican hospital over ten years, with special attention to the carbapenem resistome and biofilm formation. The isolates belonged to the global international clone (IC) 2 and the Latin America endemic IC5 and were predominantly extensively drug-resistant (XDR). Oxacillinases were identified as a common source of carbapenem resistance. We noted the presence of the family (not previously described in Mexico), the and the found in both ICs. A low prevalence of efflux pump overexpression activity associated with carbapenem resistance was observed. Finally, strong biofilm formation was found, and significant biofilm-related genes were identified, including , , and This study provides a comprehensive profile of the carbapenem resistome of isolates belonging to the same pulse type, along with their significant biofilm formation capacity. Furthermore, it contributes to a better understanding of their role in the recurrence of infection and the endemicity of these isolates in a Mexican hospital.