Student-Professor Team Publish Study of Fecal Pathogens on NYC Sidewalks
Schematic by Marjan Khan
If you live in New York City, avoiding dog feces on the sidewalk is an art form. But do fecal bacteria persist on the sidewalk after the feces are picked up? Can the bacteria transfer to your shoes? And to the indoors?
Professor of Chemistry Alessandra Leri, Ph.D., and Biology alumna Marjan Khan ’20 set out to answer these questions by quantifying the fecal pathogens enterococci and E. coli on New York City sidewalks, on shoe soles, and in the indoor environment.
Their study, “Faecal indicator bacteria on indoor floors linked to exterior sidewalk contamination in New York City,” was published this week in the journal Indoor and Built Environment.
The paper reports startlingly high numbers of fecal pathogens on the sidewalks of the Upper East Side. Professor Leri and Khan traced the bacteria to shoe soles and indoor floors, finding very high numbers on carpets and significantly lower numbers on adjacent uncarpeted flooring. They found the greatest amount of fecal bacteria on floors near a building entryway and lower numbers in the interior of a building where there was less foot traffic.
According to Professor Leri, the research could help prompt a change in daily habits.
“The abundance of disease-causing bacteria of fecal origin on the sidewalks and the alarming evidence that they are tracked indoors should help convince people to remove their shoes inside the home,” she said.
MMC’s Sciences Division has a strong track record of faculty-student collaborations. Khan conducted three years of lab work on the project while enrolled at Marymount Manhattan; she is currently a Ph.D. student in Biomedical Sciences at the University of Florida.