Run and Tumble

The most recent lab was spent testing antiseptics and disinfectants.  We were tasked with bringing in something from home.  I didn’t want to be student #1000 who brought in mouthwash or bleach, so I asked myself what would John Wayne do?

He’d bring in the same whiskey he just used to wash out the bullet hole received while laying down the law.  I grabbed a small amount of my Jameson Irish Whiskey (40% alc by volume) and headed out to the lab.

To test it, we divided two petri dishes into five sections.  One dish was for Pseudomonas aeruginosa, the other for Staphylococcus aureus. The first section of each plate was labelled ‘0′ and streaked with an undiluted culture of the appropriate bug.

Next, we diluted 0.5 mL of each broth with 5 mL of Jameson Irish Whiskey. At 2.5, 5, 10, and 20 minutes after dilution, we streaked a section of each plate.  (I finally got to use a nifty mechanical pipette, rather than the ABCDE rubber valve, YAY!)

We left them incubating at 37 Celsius until this evening. Here are the results, growth is ranked relative to the initial streak on a scale of 0(no growth) to 4(about the same):

Minutes	P. aeruginosa	S. aureus
2.5	2	1*
5	1	3
10	0	1
20	0	0

* There was a single colony. Multiple groups working with S. aureus had an unexplained ‘no growth’ at 2.5. Let me know if you have ideas. Also apologies for the unstyled table, I’ll make it pretty after I finish studying.

This is fairly effective. Indeed, it was much more effective than Lysol against Pseudomonas, which didn’t even make a dent.  If you think 10 minutes is a long time, double check the instructions on your household cleaners.  Yeah, you’re not supposed to mop it up as soon as you spray it.  This is why.

Now, remember that this data is really only good for disinfecting flat surfaces, not as an antiseptic for actual cowboy bullet wounds, which have a lot of complicating factors. I also make no guarantees about effectiveness vs spore-formers. Finally, Jameson costs more than most similarly effective disinfectants and tastes good enough that it would be a pity to regularly use it in this manner.

P.S. If/when I start plating from home, I’ll take pictures, rather than just feed y’all tables.