Medical Geology and Antibacterial ClaysMedical Geology and Antibacterial Clays~ Move Over Penicillin ~~ Move Over Penicillin ~

Clélia Tommi & Dr. Lynda Williams

School of Earth And Space Exploration

Why do Antibacterial Clay Research?

- Overuse of antibiotics

- Proliferation of antimicrobial resistance strains

- Identification of new antibacterial agents

- What makes a natural clay antibacterial?

1

What makes a natural clay antibacterial?

- Metal cation exchange when hydrated

- Natural clay deposits where send to us to test their antibacterial properties

What makes a natural clay antibacterial?

- Metals have been used as antimicrobial agents since antiquity

- Studies indicate that different metals cause discrete and distinct types of injuries

http://www.nature.com/nrmicro/journal/v11/n6/full/nrmicro3028.html

Experimental Methods- We tested several Rhodes clays (Pit #3, #17, #34),to see if they were antibacterial

- In Vitro Antibacterial Susceptibility TestingBacterial Count

Disk Diffusion

- Mineral AnalysisX-Ray Diffraction

RockJock Analisys

In Vitro Antibacterial Susceptibility Testing

- Bacterial Count

E.coli counts (per ml)

Pit # 17Pit # 3 Pit # 34

Control

0

2

4

6

8

10

12

14

0

Rhodes Clay

Summary of bar graph showing E.coli growth in sample incubated with clay minerals

- Disk Diffusion

In Vitro Antibacterial Susceptibility Testing

Petri dishes showing the zone of inhibition for the OMT clays (24 mm), compare to the Rhodes clay who are not antibacterial

Mineral Analysis

- X-Ray Diffraction

Random powder XRDpatterns of theRhodes depositspiked with internalstandard (Al

2O

3),

showing thepresence ofmuscovite (mus),kaolinite (kao),quartz (qtz),feldspar (fsp),biotine (bio),goethite (goe),and anhydrite (anh)

Results & Conclusions- From the agar plate experiments, bacterial count, and the disk diffusion analysis, we can clearly see that the Rhodes clay are not antibacterial.

- The XRD mineralogical test shows traces of goethite and anhydrite minerals which suggest the Rhodes clays come from an oxidized environment.

- Our conclusion regarding the Rhodes clays deposits is NOT antibacterial as reported by the owner.

~ The mineralogy shows igneous and metamorphic minerals unlike the antibacterial clays.

~ Microbiology shows no inhibition of bacterial growth

~ Samples are oxidized relative to bacterial clays, and pH is circumneutral

Questions?

- Disk Diffusion

Thank you!