Technologies + Future Outlook

Microbiology

•Since we have started to harness the amazing power of bacteria, the field of microbiology has become much more prominent

•As we previously learned, we are developing new ways to utilize bacteria to our advantage!–Detergents–Mining–Textiles–Food

Microbiology

• Most bacterial cultures are processed much like we did in this lab–Swab “infected” areas–Culture bacteria on growth media–Observe colonies

–Perform culture tests*–Oxidase, indole*

–Perform gram staining procedure– Identify organism–Perform Antibiotic susceptibility testing

In the clinical lab

•However, a clinical lab has access to more $$, and are designed to be more microbiology specific than our lab.•These are some of the interesting technologies used in clinical labs around the world today!

Microbiology Technologies

Automated Laboratories

• Clinical labs now have access to a wide variety of Chromogenic Media– The chromogenic mixture contains chromogenic

substrates as Salmon-GAL, X-Gal, X-glucuronide, etc.

– Certain enzymes, produced by some bacteria, cleave these substrates, resulting in the different coloration of certain bacteria colonies.

Culturing Bacteria

•Chromogenic Agar

•Automated Identification systems–E.g. the Vitek system (bioMerieux)–Bacterial cultures are inserted into cards with a variety of different compounds, which when metabolized, will let the user know exactly what organism you are dealing with

Bacterial Identification

• MALDI-TOF system–Matrix Assisted Laser dissociated/ionized – Time

of Flight–Essentially, a machine which zaps bacteria with

a laser, causing all the proteins and cellular components of that bacteria to travel up a tube.

–Mass spectrometer – complex machine which measures the mass of particles, and tells exactly what the bacteria is, in a matter of 2 minutes–Typically takes 4-5 days to confirm positive

results

Bacterial Identification

• First let’s look at a few key terms–Antibiotic

–An antimicrobial agent, used to combat bacterial infections

–Antiseptic–Antimicrobial agent applied to the surface of

living tissue–Disinfectant

–Antimicrobial agent that is applied to non-living surfaces for sterilization

Antibiotic Susceptibility Testing

•Bacteriocidal–Kills bacteria

•Bacteriostatic –Stops bacteria from replicating, long enough so host immune system can fight off infection

Antibiotic Susceptibility Testing

•Automated Systems–The Vitek system , which we previously learned about can be used to give an antibacterial susceptibility background to a wide variety of organisms

•Diffusion Systems–Etests–Kirby Bauer Disk Diffusion tests

Antibiotic Susceptibility Testing

• A strip of specialized paper, containing different concentrations of a specific antibiotic.

• Where the bacteria stops growing tells the doctor what dose of antibiotic to give that patient (MIC – minimum inhibitory concentration)

Etests

• Works by placing antibiotic disk on a cultured agar plate, and measuring the “zone of inhibition” size

• Tells whether the bacteria is sensitive or resistant to the antibiotic, depending on the zone size

Kirby Bauer Disk Diffusion Test

•By now, hopefully we realize the importance of bacteria in our everyday lives… good or bad. •With a greater understanding of microbiology, more career opportunities open up into this exploration as well!

So why is the study of microbiology important?

• Clinical Physician– Immunologist– Microbiologist– Pathologist

• Laboratory Technician

• Food & Drink– Any major food company hires microbiologists– Same with any brewing company as well…– Wine microbiology

• Industry– Green movement in the 21st Century has opened the door to many

microbial practices– Biomining, bioremediation, biofuels

Careers in Microbiology

• Use Kirby Bauer Disc diffusion sheet in front of you, to determine “your bacterias” zone of inhibition sizes to different types of antibiotics– Which antibiotic would you use to combat this

infection?

• NB. This is the hypothetical activity to replace the actual antibiotic test… it is possible these agents do not work against the organism you have found. – You must find your organism by deducing your Gram

stain results + colony descriptions – Subsequently, determine which antibiotics are

effective against that organism

To Do Now

• Continue to work on your Lab assignment, or continue review of Chapter 24.

When you have finished