I received a Title III grant during the spring semester of 2008 in order to conduct research on the interaction between the bacteriophages present in raw sewage and antibiotic-resistant bacteria. The reason I did this research was not only to gain knowledge on the subject, but more importantly, to gain experience in the research aspect of science as well as to work closely with my faculty mentor, Dr. JoAnn Croom. Initially, I only had background knowledge on the subject from what I was taught in BIO336/Microbiology, however, by the culmination of the project, I believe I gained much more knowledge on the subject, and the realm of research as well.
My research dealt with a possible way for alternative treatment in antibiotic-resistant bacterial infections. These infections, which are virtually all acquired in hospital settings (nosocomial infections), have become the tenth leading killer in the United States, being responsible for over 90,000 deaths a year. The prevailing dogma for treating these nosocomial antibiotic-resistant infections is to attempt to kill the pathogenic bacteria with novel and more powerful antibiotics. However, this approach comes with difficulties. The two main difficulties associated with this approach are: 1.) the bacteria causing the infections will undoubtedly eventually become resistant to the new antibiotics being used to treat the acute infections and 2.) the resources to develop these new antibiotics are slowly become less available, as most antibiotics are derived from the chemicals produced by microbes, and it takes years to develop a drug ready for human use.
My research dealt with using bacteria-specific viruses called bacteriophages to kill these antibiotic-resistant bacteria. In order to harvest these bacteriophages, I collected raw sewage from the Mars Hill Sewage Treatment Plant and filtered the sewage through a microfilter specific for particles <0.5µm in size. The reason I used sewage is because there is copious amounts of bacteria in sewage and where there are lots of bacteria, bacteriophages should be present.
After obtaining the bacteriophage filtrate, I then needed to cultivate antibiotic-resistant bacteria in the laboratory. This is where the majority of my funds went for the research, as antibiotic diffusions discs are not cheap. In order to develop these antibiotic-resistant bacteria, I spread a lawn of Staphylococcus aureus (the bacterium in MRSA) on a plate of brain-heart agar. On top of this lawn I placed eight antibiotic diffusion discs. The antibiotic chemicals then diffuse out of the discs onto the bacteria, killing the vast majority of them, and creating a zone of inhibition. I would then harvest any bacteria present in this zone of inhibition as bacteria that survive this hostile environment are deemed to be antibiotic resistant. In essence, the bacterial colonies retrieved from this zone of inhibition are then antibiotic-resistant Staphylococcus aureus.
In order to test my hypothesis that the bacteriophages would be able to effectively kill the antibiotic-resistant bacteria, I then needed to introduce the bacteriophage to the antibiotic-resistant S. aureus. To do this, I plated lawns of resistant S. aureus on plates of brain-heart agar, and then spread the bacteriophage filtrate suspended in an agar medium over the agar plate, and incubated for 24 hours. Visual examination would indicate whether or not the bacteriophages were able to lyse (break down) the bacteria.
The results of my study were quite surprising. In examining the interaction between the bacteriophage filtrate and that of non-resistant bacteria as well as resistant bacteria, I found that the resistant bacteria where actually more susceptible to bacteriophage lyses. Further investigation provided a reason for this seemingly counterintuitive result. As it turns out, bacteria use approximately 5% of their resources to develop antibiotic resistance, and this disparity (even though it seems small) may be enough to make the bacteriophages better able to kill the resistant bacteria.
In conclusion, this research vastly increased my knowledge on the subject of bacteriophages and bacteria. Also, having conducted this research will certainly help me in my future endeavors in the scientific fields.
Use of Funds
As the MHC Biology Department had most of the materials needed to conduct this research, I only needed to spend approximately 100$ on the antibiotic-diffusion discs. The remainder of the grant was written off as a student stipend.
Reflection on Working with Faculty
I was lucky enough to work with Dr. JoAnn Croom of the MHC Biology Department in conducting this research. Working with Dr. Croom was undoubtedly one of the highlights of my educational experience at MHC. Dr. Croom has a wealth of knowledge in many fields and was very willing to let me pick her brain for that knowledge. I believe that working with Dr. Croom has enabled me to be a better scientist and also pushed me to try to excel in all my studies. Dr. Croom has probably had the most influential effect on my college career in the past three years, and working with her has been a pleasure as well as an education in itself. As I am graduating this semester, I will sincerely miss Dr. Croom.