engleski

The ability of biofilm formation in clinical isolates of Acinetobacter baumannii and environmental isolates of Acinetobacter junii.

Objectives: Acinetobacter baumannii is an important opportunistic pathogen that is rapidly evolving towards multidrug resistance and is involved in nosocomial infections, especially in intensive-care units. Biofilm formation by these microorganisms could be associated with the high level of resistance to desiccation and disinfection, facilitating its survival in the hospital setting. It has been indicated that the adhesion and biofilm formation might be significant for the persistence of A. baumannii on medical devices and plays an important role in pathogenesis as well as antimicrobial resistance. The aim of this work was to study the biofilm formation in clinical isolates of A. baumannii and environmental isolates of A. junii. Methods: Five isolates of A. baumannii from tracheal aspirates paediatric patients from PICU were collected during 2012 in Split University Hospital, Split, Croatia. All isolates were identical in PFGE profile, belonged to the European clone 2 lineage and epidemically present in this hospital since 2009. We compared the ability of biofilm formation of newly collected clinical tracheal isolates of A. baumannii with isolates collected in the beginning of 2009 from other samples and environmental isolate of A. junii susceptible to all tested antibiotics. The biofilm formation was tested in polypropylene tubes after 24h of incubation at 37°C by crystal violet staining, ethanol solubilisation and measurement of absorbance at 550nm. Results: Environmental isolates of A. junii showed the strongest biofilm formation when compared to the clinical isolates of A. baumannii. The biofilm formation of newly collected tracheal isolates of A. baumannii was considerably higher when compared to the isolates from the beginning of outbreak in 2009. This is the first investigation on tracheal isolates of A. baumannii in paediatric patients confirming the increase in ability of biofilm formation over time. Conclusion: The results of our pilot study indicate better ability of biofilm formation of tracheal clinical isolates of A. baumannii which were collected in 2012 than that of isolates collected in early 2009 from other samples. However, future studies are needed to confirm the consistency of our hypothesis.

Biofilm; Bacteria

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