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dc.contributor.advisorUlett, Glen C
dc.contributor.authorDesai, Devika J
dc.date.accessioned2020-10-16T02:23:08Z
dc.date.available2020-10-16T02:23:08Z
dc.date.issued2020-10-06
dc.identifier.doi10.25904/1912/3985
dc.identifier.urihttp://hdl.handle.net/10072/398419
dc.description.abstractUrinary tract infections (UTIs) are among the most common infections caused by both Gram-negative and Gram-positive bacteria, acquired in the community and hospitals. There are three main groups of UTIs: (i) lower UTIs that affect the urethra or the bladder, (ii) upper UTIs that affect the kidneys, or (iii) asymptomatic bacteriuria (ABU). Group B Streptococcus (GBS) is a Gram-positive bacteria known to cause a variety of infections in neonates, pregnant women, the elderly or immunocompromised individuals. GBS has been estimated to cause 1-2% of all single organism UTIs. GBS has been shown to form biofilms, on abiotic and biotic surfaces, protecting it from killing by antibiotics or host immune cells and promotes host colonisation. Various factors have been shown to affect the biofilm forming ability of GBS. Here we determined that LB supplemented with glucose was the optimal media for biofilm formation by a strong biofilm forming strain. We then investigated the biofilm forming phenotype of 292 clinical GBS isolates that presented with asymptomatic, acute, or recurrent infection. We found that there was no significant difference in the biofilm forming ability across the clinical presentations. We also showed a significant reduction in the biofilm forming ability of a strong biofilm forming strain and its isogenic maeK and maeE mutants in LB supplemented with 1% glucose. A multiplex PCR screen for genes encoding bsaB, pil1, pil2a, and pil2b found that there was no significant difference in the number of strains that had the right sized fragments for all four genes across the three clinical presentations. We also found that there was a significant difference in the proportion of strains that had the right sized fragments for the pil genes across the three different levels of biofilm activity under shaking conditions. High biofilm forming strains had the lowest proportion of strains that possessed all four genes, compared to low and medium biofilm formers. Lastly, we assessed the haemolytic activity of the strains by growing them on tryptic soy agar plates supplemented with 5% horse blood and found that asymptomatic strains had a significantly higher number of strains with high haemolytic activity compared to acute and recurrent strains.
dc.languageEnglish
dc.language.isoen
dc.publisherGriffith University
dc.publisher.placeBrisbane
dc.subject.keywordsBiofilm-Forming Ability
dc.subject.keywordsHaemolytic Activity
dc.subject.keywordsClinical Group B Streptococcus (GBS)
dc.subject.keywordsUrinary tract infections (UTIs)
dc.subject.keywordsGram-negative bacteria
dc.subject.keywordsGram-positive bacteria
dc.titleCharacterisation of Biofilm-Forming Ability and Haemolytic Activity of Clinical Group B Streptococcus (GBS) Isolates From the Urinary Tract
dc.typeGriffith thesis
gro.facultyGriffith Health
gro.rights.copyrightThe author owns the copyright in this thesis, unless stated otherwise.
gro.hasfulltextFull Text
dc.contributor.otheradvisorGoh, Kelvin G
gro.identifier.gurtID000000027894
gro.thesis.degreelevelThesis (Masters)
gro.thesis.degreeprogramMaster of Medical Research (MMedRes)
gro.departmentSchool of Medical Science
gro.griffith.authorDesai, Devika J.


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