Detection of blaNDM-1, blaOXA-23, and blaOXA-58 positive Acinetobacter baumannii in an intensive care unit in Brazil

This study reports on a multidrug-resistant (MDR) Acinetobacter baumannii isolate identified through microbiological surveillance of rectal swabs from a patient admitted to an intensive care unit (ICU) of a public hospital in Pernambuco, Brazil, in 2022. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK® automated system, and species confirmation was carried out by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of antibiotic resistance genes, including blaKPC, blaIMP, blaVIM, blaNDM, blaSPM, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, and mcr-1 to mcr-10, was investigated by polymerase chain reaction (PCR). The A. baumannii isolate exhibited resistance to all tested antimicrobials and demonstrated strong biofilm-forming capacity. Molecular analysis revealed the presence of blaNDM-1, blaOXA-23 and blaOXA-58 genes, representing a concerning genetic combination associated with carbapenem resistance. The A. baumannii isolate exhibited resistance to polymyxin B but lacked mcr-1 to mcr-10 genes. Asymptomatic colonization of MDR A. baumannii in a patient at ICU underscores the risk of possible infection that may become invasive. These findings highlight the importance of continuous microbiological surveillance to monitor the dissemination of MDR pathogens in hospital environments.