This week I ran my experiment, and, as with most experiments, there were some definite hiccups. I plated my bacteria on Tuesday and started my experiment, using a blue binder divider over a small, white light to create the desired blue light effect. I was worried that the light might die overnight, but it turned out this should not have been my primary concern. When I came into school the next morning, the light was completely fine, but the stock bacteria was not. There was absolutely nothing growing on any of the stock plates, even on the control plate, so Mrs. Cole helped me make up a new batch of stock bacteria, and I re-plated. When I checked the next morning, the stock bacteria was growing no problem, perhaps too well. The bacteria growing under the blue light showed absolutely no signs of growth inhibition, and I was hoping to at least see a little less bacteria on those plates than on the control plates, but both were basically full-on lawns. With the methylene blue, the story was a little different. There was definitely not the large-scale growth inhibition I was hoping to see, but both the stock and antibiotic resistant plates with the compound were made up of very defined dots of colonies, rather than the complete coating that happened on the blue light plates. Overall, in response to my question, I would say the methylene blue worked better, although, with the available equipment, neither method is an effective way of combating antibiotic resistance bacteria.
Additionally, all of the colonies except one large one were blue, and so had obviously taken-up the dye. Mrs. Cole and I thought it would be interesting to see if the bacteria continues to grow blue if it is plated on a normal plate of agar, so I took some of the methylene blue bacteria and plated it on some mini plates to leave in the incubator over the weekend. I’m looking forward to seeing how that goes!