ISR: Campus Bacteria Survey

Some ISRs take a circuitous route, raising new questions and possibilities along the way. For Sam Smith, a social media post about the glowing wounds of Civil War soldiers led him to an investigation of bacterial biodiversity on Millbrook campus. In 1862, the Battle of Shiloh took place in the muddy countryside straddling the border of Tennessee and Mississippi, leaving countless injured soldiers strewn across the battlefield. Night fell. Stuck in the mud and suffering as they awaited recovery, wounded soldiers observed that their open wounds were faintly glowing blue-green. Medical records from the time indicated that soldiers who reported the glowing phenomenon recovered more quickly and had lower incidents of infection relative to those who didn’t observe any glowing. Over 100 years later, research revealed the presence of a bacteria that may have been responsible for devouring harmful bacteria, and that was the likely source of the luminescence. Microscopic worms called nematodes host the luminescing bacteria.

Sam sourced a batch of nematodes but found that he was unable to maintain favorable conditions for their survival. This led to a study comparing Millbrook’s pre-Covid bacterial biodiversity with the quantity of bacteria to be found now, with health and safety protocols in place to maintain the bubble.

Sam used data from a study by Alex Chalk ’16 as a baseline and began to collect his data by swabbing the front doors of MASC, the Barn, and the dining hall, as well as the dining hall glove dispenser. He swabbed all the surfaces four times over six months and then used Petri dishes to culture his samples. Sam photographed his bacteria samples and used a morphology index to identify and categorize them. He discovered 35 different colonies and used the Shannon Entropy Index to compare his findings to Alex Chalk’s 2015 data, pre-Covid.

It seems that while Millbrook’s pandemic protocols were effective in keeping the campus free of Covid, plenty of other bacteria were thriving. Sam also observed that the volume and biodiversity of bacteria only grew as the term progressed, an indication that beginning every return to campus with a quarantine period was effective.

Sam’s ISR not only challenged him to hone his data collection and lab skills, but also to be open to the possibility of answering a different question than the one asked initially. The ability to pivot, and to follow the science will undoubtedly benefit Sam as he studies biochemistry in college with an eye towards pre-med.