Browsing by Subject "faagit"

The objective of this thesis was to isolate and characterized phages from Beninese wastewater samples against clinical Acinetobacter baumannii strains for phage therapy use. A. baumannii is one of the most threatening nosocomial bacteria because most of the strains are resistant towards all commonly used antibiotics. One promising alternative treatment method could be phage therapy that utilizes lytic phages to dispose of specific bacteria. In this thesis, seven phages infecting clinical A. baumannii strains were isolated and two of them were characterized more in detail. Phages vB_AbaA_fBenAci001 (fBen-Aci001) and vB_Aba_fBenAci002 (fBen-Aci002) were members of the Friunavirus genus of the Autographiviridae family. In addition, they were the only phages characterised from their respective species to date. The genome analysis revealed 82.2% identity between the phages. No genes indicating lysogenic lifecycle, or genes encoding bacterial toxins or antibiotic resistance were identified from either of them. Phage fBen-Aci001 were infecting 4% and fBen-Aci002 were infecting 9% of tested 23 clinical A. baumannii isolates. Phylogenetic tree which was constructed based on whole genome sequences was compared to the trees that were made using tailspike proteins and capsid proteins. No correlation between genome-wide tree and trees built based on single genes were seen. In conclusion, the Beninese hospital wastewater appeared to be a good source for A. baumannii phages, as several phages were isolated and they were infecting clinical multidrug resistant strains isolated from Finnish patients. Phages fBen-Aci001 and fBen-Aci002 were concluded to be potential candidates to be used in the phage therapy though the narrow host range might negatively affect their usability.