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https://ptsldigital.ukm.my/jspui/handle/123456789/500651| Title: | Characterisation of klebsiella pneunmoniae and potential of klebsiella lytic bacteriophages in antibacteria and-biofilm formation |
| Authors: | Baqer Abeer Ameen (P91431) |
| Supervisor: | Norefrina Shafinaz Md Nor, Dr. |
| Keywords: | Klebsiella Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia |
| Issue Date: | 9-Sep-2021 |
| Description: | Members of the genus Klebsiella are among the leading microbial pathogens associated with nosocomial infection. The increased incidence of antimicrobial resistance in these species has propelled the need for alternate/combination therapy to aid clinical treatment. Bacteriophage therapy forms one of these alternate strategies. Bacteriophage, a virus that infects bacteria, has been listed by WHO as one of the alternative antimicrobial treatments and used in several countries to treat many infections. Nonetheless, to date, studies related to phage therapy against K. pneumoniae are limited. Therefore, this study was aimed to evaluate the efficacy of lytic bacteriophages as the therapeutic agent against MDR- K. pneumoniae. The first objective of this study was to characterise the K. pneumoniae host isolates. Next was to isolate and characterise the bacteriophages infecting selected K. pneumoniae. The phage��s ability to infect and kill planktonic cultures was studied by the Killing Curves as well as the ability to inhibit biofilms was also evaluated using an in vitro static biofilm system (microtitre-plate). Then, the evaluation of the efficiency of bacteriophages therapy either as cocktail alone or in combination therapy with antibiotics in the eradication of K. pneumoniae biofilm. Antimicrobial susceptibility profile was detected by antibiotic susceptibility test. Genotyping of virulence factors genes and capsular typing for the clinical isolates were done using molecular approach Polymerase chain reaction (PCR). The result showed that, among all the MDR isolates, 26% were K. pneumoniae carbapenemase (KPC) with high detection of virulence factors, which included uge, Kfu, ompK35, ompK36, ybtS, mrkD, entB, fimH, rmpA. Virulent capsular type (K) 2 and K20 were frequently detected amongst the isolates used. Therefore, these isolates were used as the main host to isolate a collection of bacteriophages from sewage, lake and cockle samples. Among 58 isolated lytic phages, eight phages were further characterised by one step growth curves, stability testing and lytic ability. Characterisation was further done through transmission electron microscopy (TEM), restriction fragment length polymorphism (RFLP), and random amplification of polymorphic DNA (RAPD) typing analysis and protein profiling. Phylogenetic trees for 4 important proteins were constructed for two selected phages using tail fiber protein and revealed phages that related to the same family were clustered together. TEM results showed that all selected bacteriophages were from Podoviridae family except for one phage identified as in Myoviridae family. All eight phages showed high efficiency in reducing bacterial concentration with high stability under different physical and chemical conditions. Biofilm inhibition assay of K. pneumoniae revealed the three selected phages either as single, in cocktail or in combination with antibiotics demonstrated the efficiency of phage therapy was dependent on multiplicity of infection (MOI) and combination therapy was more efficient compared to any other treatments for biofilm inhibition. Based on these findings, we report a high rate of antibiotic-resistant (carbapenem resistance genes) among K. pneumoniae strains, confirming the diversity and rapid evolution of β-lactamases in K. pneumoniae clinical isolates. The phage cocktail was shown to be effective in reducing and inhibiting biofilms formed by the clinical strains showing it to be promising not only to treat for infections caused by K. pneumoniae and have potential to control biofilms produce on the surfaces of medical devices, such as catheters.,��Certification of Master��s / Doctoral Thesis�� is not available,Ph.D |
| Pages: | 348 |
| Call Number: | QR82.E6B345 2021 tesis |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi |
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| File | Size | Format | |
|---|---|---|---|
| ukmvital_130733+SOURCE1+SOURCE1.0.PDF Restricted Access | 6.11 MB | Adobe PDF | View/Open |
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