OXA-23-producing Acinetobacter baumannii isolates in L. Pasteur University Hospital in Slovakia from September 2021 to December 2021

Carbapenem-resistant Acinetobacter baumannii (CRAB) has been associated with hospital-acquired infections. A variety of methods for rapid detection of CRAB have been developed for use in clinical microbiology laboratories. The use of Bacmed 6iG2 automated AST reader and analyzer combines antibiotic susceptibility testing and detection of resistance mechanisms such as carbapenemases, metallo-β-lactamases (MBL), aminoglycoside resistance, and others. Clinical isolates of Acinetobacter baumanii were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by disc diffusion method and determined using Bacmed 6iG2 automated AST reader and analyzer (Aspiag, Czech Republic). Carbapenemase genes (blaOXA−23-like, blaOXA−24/40-like, blaOXA−51-like, blaOXA−58-like) were determined by multiplex polymerase chain reaction (PCR). Of the total 65 non-duplicated clinical isolates, 67.7% (n = 44) were carbapenem-resistant A. baumannii. Antimicrobial susceptibility testing revealed that 42 isolates were resistant to penicillins, the broad and extended-spectrum of cephalosporins, monobactams, aminoglycosides, quinolones, meropenem, and imipenem. Two isolates were sensitive to imipenem/ ethylenediaminetetraacetic acid (EDTA) and resistant to all other antibiotics. All samples were sensitive to colistin. The results obtained indicate that carbapenemase-producing clinical isolates can be successfully identified by using specific antibiotic sets. The presence of carbapenemases was confirmed by PCR.