A recent outbreak among the Tampa Bay Buccaneers earned plenty of attention for the antibiotic-resistant infection MRSA. But another bug has public health officials even more worried.
Infections caused by the Clostridium difficile bacteria, commonly known as C.diff, used to occur primarily in older adults who had received antibiotics and recently spent time in a nursing home or hospital. But in recent years, it has turned up in younger, otherwise healthy people.
This year, the Centers for Disease Control and Prevention declared C.diff one of three urgent public health threats in the U.S.
C.diff is all around us — in the air, soil, water, human and animal feces, even in food. Some people carry the bacteria harmlessly, largely because other bacteria in the gut keep it in check.
But if those beneficial bacteria are destroyed by a course of antibiotics, C.diff is potentially deadly — one reason overuse of antibiotics is a prime reason deadly bacteria are flourishing.
The C.diff bacteria can produce toxins that attack the intestines and cause symptoms including abdominal pain and cramping, watery diarrhea, fever and colon inflammation, occasionally requiring surgery to remove damaged tissue. In the worst cases, C.diff can lead to kidney failure and death.
According to the CDC, more than 2 million Americans develop a C.diff infection each year. About 250,000 must be hospitalized and 23,000 die.
Scientists are looking for different ways to control it. Both a vaccine and a drug to boost immunity are being tested in the Tampa Bay area.
Meridien Research in St. Petersburg is one of 200 study sites worldwide testing the vaccine. "I see this as one day being a universal vaccine that everyone over 50 gets, like a flu, pneumonia or shingles vaccine," said Dr. Gigi Lefebvre, principal investigator at Meridien.
The vaccine currently in development by Sanofi Pasteur would block the toxins produced by C.diff. Why not just create a stronger antibiotic? Because the bacteria would most likely eventually become resistant to the new drug, Lefebvre said. Besides, "it's better to prevent it than to have to treat the illness after it starts."
Study participants will receive three injections — some will get the real vaccine, some a placebo — over the course of a month. Researchers will follow participants for three years to see if any develop signs of infection. "From early studies of the vaccine, we already believe it works very well at preventing illness, she said.
Those at highest risk for serious illness include the very young, adults over 50, anyone with a weakened immune system and those with a previous C.diff infection. Treatment can be long and difficult. Twenty percent of patients will relapse after treatment; 65 percent of that group will get a second bout of illness.
The bacteria presents huge challenges to health care facilities. It releases spores that can live on surfaces and infect others for months. The spores are also resistant to most antibacterial hand sanitizers and cleaning products, except for chlorine bleach. Hospital patients with C.diff must be isolated with strict infection control precautions.
"To have a vaccine to protect against C-diff illness would be tremendous. It would be a major breakthrough," said Dr. Sally Alrabaa, an assistant professor of medicine in the division of infectious disease and international medicine at the USF Health Morsani College of Medicine.
USF is enrolling C.diff patients in a study of a drug containing antibodies that would deactivate the toxins which cause C.diff symptoms. "Our hope is that it will shorten the course of the infection so patients feel better sooner or at least have less severe symptoms," Alrabaa said.