engleski

Survival of emerging pathogen Acinetobacter baumannii in water environment exposed to different oxygen conditions

Bacterium Acinetobacter baumannii is a leading cause of hospital infections. Over the last decade, its occurrence in natural environments outside hospital settings has been reported. The aim was to examine the survival of A. baumannii in water media exposed to different range of oxygen supply in order to predict its behaviour in the environment. The abundance of five A. baumannii isolates was monitored in nutrient-depleted and nutrient-rich water media in aerated, intermediate and anaerobic conditions (oxygen saturation 96, 56 and 0%, respectively). A. baumannii survived in both media in all tested oxygen concentrations for 50 days. In nutrient-rich water survival of A. baumannii was lowest in anaerobic conditions, while in nutrient-depleted water there was no difference in survival regardless of oxygen availability. A. baumannii formed translucent small colony variants as the fast response (after 1 day) and dormant cells as the prolonged response (after 14 days) to anaerobic conditions. TEM images showed the outer membrane of coccobacillus dormant cells up to four times thicker than in regular cells. Once in the environment, A. baumannii is able to survive regardless of the availability of dissolved oxygen, which represents a serious public health concern.

Acinetobacter baumannii ; anaerobic conditions ; dormant cells ; oxygen ; small colony variants ; water

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