Influence of ecological factors on virulence properties of clinically relevant Acinetobacter baumannii

Bakterija Acinetobacter baumannii uzrokuje teńke infekcije imunosuprimiranih bolesnika zbog otpornosti na antibiotike i dezinficijense te posjedovanja brojnih faktora virulencije. Multiplo-rezistentni sojevi ove bakterije osim u bolničkom, pojavljuju se i u izvanbolničkom okolińu. Cilj disertacije bio je definirati ekolońke čimbenice koji uvjetuju preņivljavanje klinički značajnih A. baumannii u okolińu. Ispitivano je preņivljavanje okolińnih i kliničkih izolata A. baumannii u različitim abiotičkim (temperatura, pH, dostupnost nutrijenata, koncentracija otopljenog kisika, isuńivanje) i biotičkim (interakcija s mikroskopskim organizmima) uvjetima. TakoĎer su kvantificirani faktori virulencije (biofilm, pelikula, povrńinska pokretljivost) kao mehanizmi koji pospjeńuju preņivljavanje A. baumannii. Klinički značajni izolati A. baumannii posjeduju izraņene faktore virulencije te su otporni na ńirok spektar okolińnih uvjeta. Prirodni zeoliti uspjeńno inhibiraju faktore virulencije A. baumannii te kao ekonomski prihvatljivi i dostupni materijali mogu pronaći primjenu u uklanjanju ovog patogena iz okolińa. Rezultati ovog istraņivanja omogućuju predviĎanje ponańanja A. baumannii u okolińu te pruņaju osnovu za razvoj metoda uklanjanja ovog patogena iz okolińa.Acinetobacter baumannii causes severe infections in immunosuppressed patients due to resistance to antibiotics and disinfectants. Multidrug resistant A. baumannii isolates are common in hospital setting but also in the environment. The aim was to determine which ecological factors contribute to the survival of clinically relevant A. baumannii in the environment. The survival of clinical and environmental A. baumannii isolates was tested under different abiotic (temperature, pH, starvation, dissolved oxygen concentration, dessication) and biotic (interaction with microscopic organisms) conditions. Virulence factors (biofilm, pellicle, surface motility) as survival mechanisms were also determined. Clinically relevant A. baumannii express strong virulence factors and are able to survive a wide array of ecological conditions. Natural zeolites successfully inhibit A. baumannii virulence factors and as economically accessible materials could find application in the removal of this pathogen from the environment. The results of this research provide insight into the behaviour of A. baumannii as well as a starting point for the development of methods to remove this pathogen from the environment