AsPICI elements are novel in terms of their biology it is thought that they canserve as a novel antimicrobial therapy and utilised as a ‘Trojan Horse strategyin vivo’. By exploiting the relationship between the conflicting phage andbacterial genomes, we can begin to realise the potential of PICIs to hijackintegral proteins encoded by the phage to interfere with phage reproductionstrategies and genome packaging mechanisms.
In doing so, the helper phage is able to efficientlyreplicate, package and mobilise synthetic PICI elements only, which can; introduceaccessory virulence factors into a new host, provide the ability to supressantibiotic resistance in different species of bacteria (thus making themsusceptible to antibiotics), or target biofilm formation in cannulas andcatheters etc. By engineering PICI elements in this way it is possible totarget specific strains of bacteria (even within the same species) withoutdisrupting the natural microbiome of other commensal symbionts present indifferent niches (i.e. within the colon).
As a result, PICIs can provide thekey to developing a novel antimicrobial treatment which can circumvent the complicationsassociated with traditional antimicrobial therapies in a strain specific mannerwhile potentially eliminating the need for broad spectrum antimicrobialtreatments which exacerbate the myriad of ill effects associated with AMR.Theexperimental aims involve exploring new and better medicines which can combatbacterial infections using synthetic phage-inducible chromosomal islands(PICIs). Using a dual science approach I will attempt to characterise differentPICI elements in different species of bacteria including Staphylococcus aureus, Enterococcus durans, Enterococcus faecalis andEscherichia coli. Theoretically, by modifying the PICI DNA and proteins itis possible to target different bacterial cells in a strain specific manner,therefore this approach has great potential to see the emergence of a new antimicrobialtreatment with means to fight off bacterial related infections within clinicaland agricultural settings. Additionally, as this topic is relatively new andunexplored, expanding upon the PICI family to include more species and gain adeeper insight into the functionality of many genes which remain ‘unknown’ or’hypothetical’ is also an area which I am keen to address.The work involved is primarily based on bacteriology where experimentssuch as phage titration assays will be performed todetermine the number of phage particles in the original culture so that knownamounts of virus can be used to infect cells during subsequent experiments. Phage induction will be carried outto produce PICI particles which can manipulate helper phage mechanisms tobecome mobilised, thus enabling transfer of their own genetic material (i.
e.antibiotic resistance genes) at high frequencies, to susceptible bacteria viahorizontal gene transfer. Complementationassays using plasmids will be employed to obtain information on the location ofgene mutations (if present on different genes). It is also possible to use the complementationassay to determine the relationship between the genotype and phenotype, i.
e.the molecular events which govern specific mutations, conferring characteristicphenotypes observed in different diseases. In addition to other culture basedand culture independent methods used, computational analysis will be will be carriedout to create and check genomic mutations (i.e.
base deletions) in bacterialand phage DNA sequences while enabling the design of specific oligopeptideprimers for use in PCR. The design of microfluidic devices will be applied tothis study and serve as a valuable tool to obtain rapid turnover of data in theform of colorimetric readouts.