A new study suggests that Fusobacterium necrophorum, the bacterium associated with a “forgotten disease,” is, in fact, the cause of more sore throats than the more commonly considered Group A strep bacterium among the college-aged population. Researchers, led by Robert Centor, MD, a professor in the Division of General Internal Medicine at the University of Alabama at Birmingham (UAB) and a noted authority on sore throats, strongly urge frontline providers, such as those who serve in EDs across the country, to consider F. necrophorum when evaluating young adults with pharyngitis, and to treat accordingly.1
Why is this important? Because F. necrophorum pharyngitis is the leading cause of Lemierre’s syndrome, a very serious disease that largely affects adolescents and young adults. Lemierre’s disease frequently requires long, complicated hospitalizations, and proves fatal in 5% of cases, explains Centor. While rare, Centor observes that Lemierre’s disease occurs more frequently than acute rheumatic fever, which is a complication of strep bacterium.
Centor explains that Lemierre’s disease was much more prominent in the early part of the 20th century. “It was greatly diminished in the 50s, 60s, and 70s, and then started coming back in the 80s, about the time we started being a little bit more prudent about using antibiotics for sore throat,” he explains. While Lemierre’s disease is more common than it has been in the past, it is frequently termed in the literature as “the forgotten disease.”
Centor ads that the F. necrophorum bacterium doesn’t just cause Lemierre’s syndrome. “It is also the most common cause of peritonsillar abscess in [the young adult] age group, and this age group is the most likely population to get peritonsillar abscess,” he explains.
A peritonsillar abscess is a deep infection of the head or neck that can lead to more serious complications, including Lemierre’s disease and sepsis.
Watch for red flags
Centor, who is known for developing the Centor Criteria, a set of criteria developed to quickly ascertain the presence of Group A strep infection in adults presenting to the ED with sore throat,2 says that what prompted his latest study was the observation that only about 50% of patients showing all the signs of a bacterial infection were testing positive for strep. “I kept wondering what else is going on,” notes Centor. “I really didn’t think viruses were the cause.”
The study involved an analysis of 312 college students at UAB’s Student Health Clinic. Investigators detected F. necrophorum in more than 20% of patients with symptoms of sore throat. Group A strep was only detected in 10% of the cases, and Group C or G strep was detected in 9% of the cases.
Centor says that this is the first study in the United States to show that F. necrophorum causes a significant number of pharyngitis cases in the young adult population, and that the signs of such an infection closely resemble strep throat.
Unfortunately, while investigators developed their own research assay, a polymerase chain reaction (PCR) test for F. necrophorum, to carry out their study, there is no rapid test available to clinicians to verify the presence of the bacterium, as there is with strep. Consequently, clinicians need to rely on physical examination to determine if a bacterial infection is likely.
“If a sore throat is not getting better after two or three days, it is not simply a sore throat. That is red flag number one, and certainly if the sore throat is getting worse, that is cause for concern,” explains Centor. “Also, routine sore throats do not cause drenching night sweats and they don’t cause rigors.”
Another red flag is swelling on one side of neck. “This could be either a peritonsillar abscess or a suppurative jugular vein clot that is infected,” notes Centor. “If you get someone on antibiotics right away, they should get better.”
Select effective treatment
However, it is important to prescribe the right antibiotics, stresses Centor. “The big mistake that happens with too many PCPs [primary care physicians], which includes pediatricians, general internists, family physicians, and too many ED docs, is that they give a Z-Pac [azithromycin] in this age group,” he says. “If you are going to give empiric therapy, you ought to prescribe penicillin or a cephalosporin.”
Centor notes that F. necrophorum in this young adult population is almost never sensitive to azithromycin. Further, he makes the case that everything that is resistant to penicillin or amoxicillin or a first- or second-generation cephalosporin is already likely resistant to those drugs, so you are not likely to create any staph resistance because staph is already resistant to penicillin. “Strep is still sensitive to penicillin after all these years, so I don’t think we are contributing to the antibiotic resistance problem by treating these people,” he says.
Centor acknowledges that while his findings are nonetheless likely to raise concerns about the overuse of antibiotics, he points out that 6% of the population, aged 15 to 30, seek medical attention each year for a sore throat. “It is a pretty important problem,” he says. “It is usually just a sore throat, but our job is to make sure that we don’t miss the really serious ones.”
Centor would like to collect more data on F. necrophorum-related infections, and he would also like to see a rapid point-of-care test developed for the F. necrophorum bacterium. “It would be helpful to ED docs, people who work in college health, pediatricians who take care of adolescents, and family docs who take care of young adults,” he says.
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Centor R, Atkinson P, et al. The clinical presentation of Fusobacterium-positive and Streptococcal-positive pharyngitis in a university health clinic: A cross-sectional study. Ann Intern Med 2015;162:241-247.
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Centor R, Witherspoon J, et al. The diagnosis of strep throat in adults in the emergency room. Medical Decision Making 1981;1:239-246.
• Robert Centor, MD, Professor, Division of General Internal Medicine, University of Alabama, Birmingham. E-mail: [email protected].
