Long nails are in, but what lies underneath? Bacteria and fungi, an expert says.

Long nails are a major trend these days, seen on the hands of superstars like Cardi B and Billie Eilish. But a biologist warns this new trend may come with health hazards when considering what may be growing underneath. 

Jeffrey Kaplan, a biology professor at American University, told USA TODAY that the area under the fingernail in the crevice is where most of the bacteria live.

"The longer the nail, the more surface area there is for microorganisms to adhere," he said. "Studies have found 32 different bacteria and 28 different fungi underneath fingernails."

Kaplan said it doesn't matter if you have long artificial nails, long natural nails, gel nails, acrylic nails or nail polish, because there is an increased probability of carrying microorganisms which makes it more difficult to decontaminate with handwashing or scrubbing.

Studies find MRSA, staph underneath

One study found MRSA, an antibiotic-resistant bacteria that causes serious infections in hospitalized patients, underneath half of the fingernail samples collected, according to Kaplan.

A judge checks on the contestants' nails during a nail art creative design contest at the China 2011 Hair and Beauty exhibition in Beijing, China.

Also, some of the bacteria under nails can be found on the skin like staphylococcus which can lead to an infection.

"You can transmit fingernail bacteria to your system by scratching, nail-biting, nose-picking and finger-sucking," Kaplan said. 

He said the worst thing that could happen from the bacteria and fungi is a nail infection, which would not be life-threatening, but could leave your fingernails disfigured. 

Infant deaths linked to long fingernails

That is why most, if not all healthcare workers, are required to wear short nails due to being at risk for transmitting disease, according to Kaplan..

Two nurses at an Oklahoma City hospital may have contributed to the deaths of 16 babies in 1997 and 1998 because of bacteria found underneath their long nails, The New York Times reported

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Epidemiologists found a link between the deaths of the infants in the neonatal unit and the bacteria under the nails but did not prove it was the definite cause. 

"When surgeons scrub for surgery and then they test their hands, there's always bacteria under the fingernail and you can't get rid of it," Kaplan said. 

Long nails trend on social media

Kayla Newman, a nail tech based in North Carolina, told USA TODAY that none of her clientele has had infections or "nasty nails" in her eight years of service.

"Generally people who have long nails know how to maneuver with them and keep them clean," she said. "If you're spending upwards of $60 to get your nails done and you don't keep them clean, that doesn't make sense."

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Newman has seen the trend for long nails grow over the last couple of years, and social media platforms like Instagram and TikTok showcase artistic designs on nails that can be over 2 inches long. 

She said the most common complaint she gets from clients who have long nails are broken nails, especially if they are new to the trend.

Newman suggests for people with long nails to regularly make appointments with their nail tech because the strength of nails can shift when they grow out. 

"Nails are an awesome luxury to have," she said. "I encourage people to get them done because when you look at your hands and see them nice and done whether they are long or short, it makes you feel amazing."

Two-time Olympic champion Gail Devers of the U.S. sports her long green finger nails at the indoor track and field meeting in Erfurt, eastern Germany, Feb. 5, 1997. Devers finished third in the 60m sprint.

Follow reporter Asha Gilbert @Coastalasha. Email: