SAN FRANCISCO — Community-onset Clostridium difficile infection that is not antibiotic related has emerged as a multinational problem that can be life threatening, said Dr. Sarah S. Long, chief of infectious diseases at St. Christopher's Hospital for Children, Philadelphia.
The conventional way of thinking about C. difficile infection was that it was usually associated with antibiotic use, mainly affected adults, was not life threatening, and seldom produced severe diarrheal illness in children. “Throw that [way of thinking] away. You have to start thinking and worrying about C. difficile as community onset without antibiotic exposure,” Dr. Long said at the annual meeting of the American Academy of Pediatrics.
The more modern C. difficile shows antibiotic resistance that is probably caused by widespread use of fluoroquinolones. It has mutated to lose a regulatory gene that normally suppresses production of toxin by the organism. The mutated form produces 16–20 times the amount of toxin as that of the organism without the gene deletion.
The global occurrence of this antibiotic-resistant, highly toxin-producing organism could increasingly cause problems for “an unprepared planet,” she said.
Four healthy people died recently in Philadelphia from C. difficile infection after failing treatment with multiple antibiotics followed by colectomies. Two of the infections were in postpartum women. “C. difficile in pregnant ladies and post partum can be a very severe disease,” said Dr. Long.
Clinicians should consider C. difficile infection in otherwise healthy patients with diarrhea persisting beyond 3 days, whether or not the patient has been exposed to antibiotics, especially if there's blood in the stool or the patient is feverish or toxic appearing. “Put that on your list of things to worry about alongside Salmonella, Shigella, Campylobacter, and … Escherichia coli.”
Culture isn't helpful for diagnosis. A test for toxin in the stool is the diagnostic test of choice. An enzyme immunoassay for toxin, which can give a result in 2 hours, is a good test. Specialists also may order a cytotoxin assay on stool. Nearly 90% of patients will respond to treatment with metronidazole for 10 days, but 20%–25% will relapse. Of those, half will relapse again after retreatment. There is no standard therapy for chronic recurrences, but a number of antibiotic regimens or fecal transplants have been tried.