Acne sprouting from eating greasy food or too much chocolate is a bit of an old wives’ tale; these days we’re often told that bacteria is the real culprit. Now it turns out that may be a wives’ tale as well, at least partially.

While the bacteria Propionibacterium acnes is strongly linked to acne, scientists aren’t exactly sure how it facilitates the skin disorder. To try and find the cause, researchers at the David Geffen School of Medicine at the University of California, Los Angeles decided to inspect people’s pores, 101 people to be exact. Using drugstore pore-cleansing strips, the researchers took samples from 49 people with acne and 52 people without it.

P. acnes was found on everyone’s skin in the study, but there were some distinct differences when the researchers took a closer look. There were dozens of strains of the bacteria in the samples and 66 new ones previously unknown to scientists. Two of the strains, RT4 and RT5 were only found on the skin of people with acne. RT6 was only found on healthy skin.

While RT4 and RT5 may have a part in causing acne, RT6 may actually work to keep skin clear. Study lead and molecular biologist Huiying Li says RT6 may operate like probiotics in the intestines – endosymbiotic bacteria that combat nasty, destructive, parasitic bacteria.

Many prescription acne medications on the market can be harsh, and some orally-taken treatments can even lead to birth defects in pregnant women. If these bacteria strains play the roles suggested by the study, it could help scientists develop new, gentler medications that take advantage of PT6’s beneficial functions and are only administered topically.

Whatever the causes, researchers may be onto a new generation of acne treatments.