TULSA, Okla. -- Whether you call them pacifiers, binkies or soothers, parents call them lifesavers for comforting a fussy baby.
But a new study by Oklahoma State University scientists shows they also harbor germs that can make a child sick, perhaps chronically so.
Tom Glass, professor of forensic sciences, pathology and dental medicine at the university's Health Sciences Center in Tulsa, suspected that would be the case. But he and his fellow researchers couldn't believe the bacteria they found.
Glass began the study by gathering pacifiers from families chosen at random at a Tulsa wellness center. His team of researchers swiped the surface of the pacifiers in an agar plate, then cut them up and tested the inside of the binkies, too.
"So, we can actually determine what is growing on the surface of it," said Glass. "But more importantly, what's growing down in those pores."
Standard lab cultures showed strep bacteria, various strains of staph, including Staphylococcus aureus, plus the bacteria that causes pneumonia. The pacifier samples also exhibited the yeast that causes thrush.
In all, 40 different species of bacteria were isolated from the 10 pacifiers tested.
Among them was Candida albicans, an aggressive and opportunistic strain that causes thrush in infants and vaginal infections in women, according to Jay Bullard, senior lab technician at OSU HSC.
"It's one of the most common yeast infections," Bullard said.
Even worse, the tests revealed mold.
"These are the kinds of mold that cause respiratory distress. Asthma-like symptoms," Glass said. "That was one of the most distressing parts of the whole study. We also found bacteria we did not expect that, by nature of their very being, release poisons into the system."
The research team grew even more concerned when the study revealed another set of dangerous organisms, the so-called gram-negative bacteria. The team's research paper indicates that bacteria produces "powerful modulators of the human immune system" -- the body's first line of defense against infections and illnesses.
"We have no idea what this was doing to the child's immune system or system in general," Bullard said.
After considering the findings, Glass now worries pacifiers are providing a way for certain germs to infect babies and then reinfect them over and over again.
"We sampled the nipple of the pacifier and we sampled the shield and found corollary organisms there," said Glass. "So, that very often children will have a little red ring around their lip and (parents) say, 'Well, the child was just using the pacifier too much.' It's more likely that the pacifier has gotten infected."
The type of organisms the study revealed, and the levels on the pacifiers, lead the doctor to believe binkies could make babies sick.
"Persistent or recurring ear infections, persistent or recurring colic, all of those are the kinds of organisms that we found in or on the pacifier," said Glass. "The baby's colicky. What do we do? We put the pacifier in, which is supposed to make the baby less colicky. But in reality, is providing everything we need to make the colic persistent."
This is alarming news to parents such as Cyndi Cathey, who, along with husband, Bryan Cathey, of Tulsa, see pacifiers as helpful in soothing their 4-month-old child, Bryson.
Like most new mothers, Cyndi Cathey worries about germs and makes time every night to scrub the pacifiers, bottles and nipples. However, her hard work may not pay off.
In their study, the researchers found there are three methods parents typically use to clean their baby's pacifier. Some parents simply dust it off on their sleeve. Others clean it off with a wet wipe.
"A third way that people deal with the pacifier dropping on the floor is for the mother to pick it up and put it in her mouth," Glass said.
While many mothers would never consider that option, Glass suggests that is actually the best way to clean the pacifier, "Because the baby's immune response comes from the mother, at least for the first six months," he said.
At the end of each day, Glass recommends that parents scrub the baby's pacifier or bleach it. However, his team's study found those germs just keep growing.
The best defense is to toss a pacifier after two weeks and use a new one.
"We know that it takes two weeks for this pacifier to become so contaminated that you can't decontaminate it by putting it in the dishwasher or putting it in boiling water," Glass said. "By two weeks, what has happened is the microorganisms, the germs, have formed a complex structure called a biofilm. It's rather impervious to Clorox, baking soda, to boiling."
Glass recommends parents start each of the 14 days with a baggy filled with clean pacifiers.
"Put them in the baggy and then take them with you," he said. "As the child drops it, and puts it down on surfaces that you know are contaminated, just take the pacifier away. Put it in the used pacifier bag, get a new one out and give it to the child."
The research team also recommends replacing pacifiers after the first symptoms of illness, after a fever breaks, and as soon as the child recovers.