An ongoing dialogue on HIV/AIDS, infectious diseases,
February 21st, 2015
Fusobacterium, Pharyngitis, and the Limits of Limiting Antibiotics
A paper on pharyngitis in young adults, just published in the Annals of Internal Medicine, is creating a controversy in the intersecting worlds of primary care and Infectious Diseases. The first author is Robert Centor, of the famous Centor criteria that assess the likelihood of group A strep. He’s been writing about our need to expand diagnostic considerations in sore throat for several years, starting with this excellent editorial.
The Physician’s First Watch summary of the new paper was spot-on, so I’ll just quote them here (bolding mine):
Some 310 young adults (aged 15–30) presenting with pharyngitis at an Alabama university clinic underwent polymerase chain reaction testing for bacteria in throat swab specimens; 180 asymptomatic students were also tested. Fusobacterium necrophorum was identified in 21% of patients with pharyngitis (and 9% of asymptomatic students), while group A streptococcus was found in just 10% of patients (and 1% of asymptomatic students). Clinical presentations were similar for F. necrophorum and group A strep.
From the perspective of patient management, there are two interpretations circulating about this paper — one that it encourages antibiotic prescribing, the other that it does no such thing.
The controversy is nicely encapsulated in this comment on a listerv (remember those?) for pediatricians, which was shared with me from a very reliable source (she didn’t write the comment):
OMG! So if it is cultured [sic] from the throat, it is the cause of the infection,right? So now everyone who has this in their throat and doesn’t feel well needs antibiotics, right?
Allow me to take both positions:
Pro Antibiotics: Some really terrible exudative pharyngitis in young adults is group A strep negative. This study shows that fusobacterium is more common than strep in this age group. We know it can cause peritonsillar abscess and, even worse, septic jugular vein thrombophlebitis (Lemierre’s syndrome), both of which are preceded by sore throat — and both of which are more common than acute rheumatic fever. If we treat the really sick teenager and young adults who are group A strep negative with an antibiotic with activity against fusobacterium — penicillin and other beta lactams, please, not azithromycin — not only will these youngsters get better faster, but we can prevent potentially life threatening complications.
Anti Antibiotics: Most pharyngitis is causes by respiratory viruses. There is no way to detect fusobacterium as a cause of pharyngitis in clinical practice, so if most cases get treated “empirically”, this will be massive unnecessary treatment. Detection of the organism by polymerase chain reaction in the study does not prove that fusobacterium is the cause of the pharyngitis, especially since it’s found in a not insignificant proportion of asymptomatic individuals (9%). There is furthermore no proof that treatment of fusobacterium will hasten symptom improvement or, more importantly, prevent Lemierre’s.
The latter position was nicely articulated in an accompanying editorial in the Annals written by my colleague Jeffrey Linder — a primary care physician who has published extensively on this subject and admittedly a much more reliable expert on the topic than I.
But let me risk taking a position slightly different from Jeff and, I’m sure, many of my ID brethren, one that I confess is rooted not so much in data but in experience caring for several young adults with Lemierre’s. Importantly, Jeff and I don’t disagree — it’s more a matter of emphasis.
Remember this — patients with Lemierre’s are often critically ill. They frequently require ICU care, have high spiking fevers with staggeringly high white blood cell counts, and invariably have multiple septic pulmonary emboli with potentially other metastatic sites of infection, including the brain.
It’s a terrifying illness — these are most commonly previously healthy high school and college-age kids, so the stakes are high. No, we don’t know that treatment of severe pharyngitis “caused” by fusobacterium will prevent Lemierre’s, but doesn’t that make biologic sense?
So let’s go with the pediatricians’ common-sense approach to clinical care, and make a decision about antibiotics based on that sixth sense of “is the kid really sick?” If so, go with some penicillin — especially if at the first encounter they didn’t get treated, and then they come back a few days later even worse.
Or, if you prefer, listen to the guru of pharyngitis himself, Dr. Centor, and his interpretation of national guidelines:
We believe that following the American College of Physicians/Centers for Disease Control and Prevention guidelines endorsed by the American Academy of Family Physicians would decrease the risk of Lemierre syndrome in adolescents and young adults. Using these guidelines, physicians can choose to prescribe antibiotics for patients with a pharyngitis score of 3 or 4 (three or four of the following: fever, absence of cough, tender anterior cervical lymph nodes, tonsillar exudate).
Makes sense to me.