Presence of Acinetobacter baumannii in natural environment in Croatia

INTRODUCTION: Acinetobacter baumannii is a leading emerging pathogen of the 21st century, which is frequently recovered from patients during hospital outbreaks. Acute community-acquired human infections suggest a source of this pathogen outside of the hospital settings. The significance of environmental isolates in the epidemiology of A. baumannii is under a great concern worldwide. THE AIM: In this study the overview of the presence of A. baumannii in natural environment in Croatia is given. METHODS: The recovery of A. baumannii was performed on commercial CHROMagar Acinetobacter supplemented with cefsulodin sodium salt hydrate after incubation at 42C/48h. Identification was performed by routine bacteriological techniques and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) on cell extracts. The antibiotic resistance profile was determined by Vitek2 system and interpreted according to EUCAST and CLSI criteria for clinical isolates of A. baumannii. RESULTS: A single isolate of A. baumannii was incidentally recovered near the City of Pula from 0.1g of acid paleosol influenced by illegally disposed solid waste. The isolate showed multidrug-resistance (MDR) to fluoroquinolones, gentamicin and trimethoprim-sulfamethoxazole. Three isolates of A. baumannii were recovered from 0.01-1g of technosol at a dump site situated above City of Rijeka in a karst pit. All three isolates were MDR and shared the complete or intermediate resistance to carbapenems, fluoroquinolones, amikacin, ampicillin-sulbactam and ticarcillin- clavulanic acid. Four isolates of A. baumannii were recovered from 10mL of water from Sava River downstream of the City of Zagreb after discharge of the urban wastewaters into the natural recipient. All four isolates were MDR and shared the resistance to carbapenems, fluoroquinolones, aminoglycosides and ticarcillin-clavulanic acid. CONCLUSION: MDR A. baumannii were present in natural environment influenced by human solid and liquid waste. The proper management and disposal of human waste is mandatory to prevent the spread of MDR A. baumannii in nature.