Abstract
The aim of this study was to find the source of Acinetobacter baumannii in the intensive care unit (ICU) after an outbreak during the coronavirus disease 2019 (COVID-19) pandemic, as there was no A. baumannii detected on usually screened susceptible surfaces. The screening of the ICU environment was done in April 2021 when eleven different samples were taken. One A. baumannii isolate was recovered from the air conditioner and was compared with four clinical A. baumannii isolates obtained from patients hospitalized in January 2021. Isolates were confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), minimum inhibitory concentrations (MICs) were determined, and the multilocus sequence typing (MLST) was performed. The molecular identification of A. baumannii isolates as ST208, the presence of the same bla(OXA-23) carbapenemase gene, and the same antibiotic susceptibility profile suggest that the isolate recovered from the air conditioner is the same as the isolates recovered from hospitalized patients. The environmental isolate was recovered three months later than the clinical isolates, emphasizing the ability of A. baumannii to survive on dry abiotic surfaces. The air conditioner in the clinical environment is an important but undoubtedly neglected source of A. baumannii outbreaks, hence, frequent disinfection of hospital air conditioners with appropriate disinfectants is mandatory to mitigate the circulation of A. baumannii between patients and the hospital environment.