Effect of the bacteria Escherichia coli physiological state on the phage T7 efficiency of multiplication

Odpornost na antibiotike pri bakterijah predstavlja vedno večji problem, saj vedno bolj narašča. To je pripomoglo k vrnitvi ponovnega zanimanja do fagne terapije, ki temelji na uporabi bakteriofagov za zdravljenje bakterijskih okužb pri ljudeh. Bakteriofagi so bakterijski virusi, ki okužijo bakterijo in jo nato lizirajo na mestu okužbe. Med bakterije odporne na antibiotike, spada tudi bakterija Escerichia coli. Nekateri sevi so patogeni in lahko povzročijo veliko zdravstvenih problemov in bolezni. Cilji diplomske naloge so bili določiti rastne parametre faga T7 pri različnih fizioloških stanjih bakterije. Določali smo jih na podlagi neinvazivne metode, ki je zajemala določanje parametrov v šaržnih pogojih gojenja bakterije Escherichia coli, nato inficiranju bakterij z bakteriofagi in spremljanju njihove koncentracije v določenem obdobju. Na podlagi pridobljene rastne krivulje fagov, smo izračunali adsorpcijsko konstanto, določili dolžino latentne in eklipsne periode ter izračunali pomnožitveno število. Na podlagi pridobljenih rezultatov lahko trdimo, da se adsorpcijska konstanta z večanjem bakterijske rasti zmanjšuje, dolžina latentne in eklipsne periode krajšata, pomnožitveno število pa raste. Lahko potrdimo hipotezo, da fiziološko stanje bakterijske kulture vpliva na rastne parametre faga T7.Antibiotic resistance in bacteria is a growing problem as it grows. This has helped to bring back interest in phage therapy based on the use of bacteriophages to treat bacterial infections in humans. Bacteriophages are bacterial viruses that infect a bacterium and then lyse it at the site of infection. Antibiotic-resistant bacteria include Escerichia coli. Some strains are pathogenic and can cause many health problems and diseases. The objectives of the thesis were to determine the growth parameters of phage T7 in different physiological conditions of the bacterium. They were determined on the basis of a non-invasive method, which included determining parameters in batch conditions of Escherichia coli cultivation, then infecting bacteria with bacteriophages and monitoring their concentration over a period of time. Based on the obtained phage growth curve, we calculated the adsorption constant, determined the length of the latent and eclipse periods, and calculated the multiplication number. Based on the obtained results, it can be argued that the adsorption constant decreases with increasing bacterial growth, the length of the latent and eclipse periods also decreaser, and the burst size is higher.. We can confirm the hypothesis that the physiological state of bacterial culture affects the growth parameters of phage T7