Download BBiomedSc (Hons) Project Outline 2016

BBiomedSc (Hons) Project Outline 2016
Department of Pathology
University of Otago, Christchurch
Inhibition of biofilms by MTANS
Background. The presence of biofilms enables bacteria to persist on implanted medical devices despite
aggressive antimicrobial therapy. Most need to be removed for the infection to be cured causing great expense
and morbidity to the patient. The pathways of biofilm formation have been well elucidated. Recently Bao et al
demonstrated that deletion of the gene that encodes for MTAN (also known as S-adenosyl nucleosidase or Pfs)
in S. aureus reduced bacterial clumping ability and resulted in decreased biofilm formation. We have reported
the design and synthesis of several inhibitors of S. aureus MTAN, using transition state analogue theory,
including one lead compound with a 0.8 nM dissociation constant, the tightest binding MTAN inhibitor ever
reported.
Hypotheses.
1. MTAN inhibitors will inhibit biofilm formation
2. Multiple MTAN inhibitors may have increased
effects
3. Antimicrobial agents may increase the activity of
MTAN inhibitors.
Preliminary data. Several MTAN inhibitors have been
screened using a single strain of S. epidermidis and S.
aureus. The results from the most effective one are shown.
There was a dose response giving approximately 87%
reduction in biofilm formation after 48 hours incubation.
Experimental design
Figure: Reduction of biofilms (bars) by an
Use multiwell plates to form biofilm as in above
MTAN inhibitor (MTANi) and effect on cell
experiments. Crystal violet will be used to stain the
growth (line). Y axis, crystal violet retained
organisms that are retained on the wall after washing and
in biofilm (absorbance reading at 570 nm);
quantitated using an OD reader.
percent growth.
1. Perform as survey of multiple clinical strains of S
aureus and S epidermidis with single MTANS to determine the efficacy in preventing biofilm formation
2. Consider performing experiments with 2 separate MTANS to determine efficacy against multiple
strains
3. Determine the efficacy of MTANS with different classes of antibiotics for preventing biofilm formation
and against mature (72hr) old biofilms
Significance These experiments will provide basic information needed to inform development of inhibitors of
medical devices and develop new forms of treatment. The results will contribute to the programme of work
being conducted by the biofilm team under the leadership of Prof G Evans. Prof Evans will provide the MTANS.
Other team members include Dr Monica Gerth and Dr Tim Woodfield. Bao, Y., Zhang, X., Jiang, Q., Xue, T., and
Sun, B. (2014) Pfs promotes autolysis-dependent release of eDNA and biofilm formation in Staphylococcus
aureus. Medical microbiology and immunology, 1-12
Indicate preferred student expertise:
Microbiology
Supervisor:
Prof Steve Chambers
Research Group:
The Infection Group