On the rail side, TriMet has cut four of 33 jobs responsible for cleaning trains, among other duties.
On a cram-packed Line 4 bus in May, noon-time commuters gave Yeh's biology students sideways looks as they milled about, sterilized cotton swabs and plastic lab dishes in hands. The driver repeatedly glanced into an interior mirror. A few puzzled looks, but no questions.
Back at the lab, about 120 multi-colored colonies bloomed. The team has just started to sequence the different species, but Yeh said it's very likely that E. Coli and fecal bacteria are present. "People hear fecal bacteria and wonder if someone ... well, it's more about people not washing their hands," she said.
Far more worrisome, Yeh said, are colonies showing resistance to antibiotics. She said more testing is needed, but some are showing characteristics of MRSA. Highly resistant, MRSA attacks immune systems through skin breaks and plays a role in about 19,000 deaths annually, according to the Centers for Disease Control.
Line 9 bus rider Keith Myers prefers not to think about germs on the bus. It's bad enough when someone sneezes, making other riders cringe or even jump, he said.
But he assumed the cloth seats were pretty filthy.
"My strategy is to always have clothing between me and the seat," he said. "And to wash my hands when I get off. I wish I could say I always remember to do that."