Currently the infectious disease guidelines say that throat culture is the gold standard for diagnosing strep throat. However, there is growing evidence that PCR tests has a similar sensitivity and specificity as throat culture for the diagnosis of GAS. PCR tests also has a faster turn around time that most throat cultures. I believe that one of the issues with the use of PCR testing is that it is not available in many clinical settings, although a review of the literature shows that it does appear to be a very good test. -Britt
I am curious about any thoughts regarding an organism called Fusobacterium Necrophorum. Obviously, we aren't testing for this. However, there are a moderate amount of pubmed citations concerning its prevalence, and relevance, as a causative agent in a NOT small percentage of exudative pharyngitis, as well as its association with not-so-great problems like Lemierre's, bacteremia, or PTA, for example. To me, clinically, I feel like we mostly have a set of blinders on that says, "there IS NO OTHER BACTERIAL PATHOGEN BUT STREP that can produce pharyngitis--it is the ONLY THING I will consider" -- even though there are literally hundreds of diff bact in the oropharyngeal biome, at least ONE of which is documented to be a not trivial bacterial player in that space. If interested, here is an interesting article talking about it from 2017 in J Clin Microbiology--actually done right there in Los Angeles (Children's Hospital of Los Angeles)-- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5377842/pdf/zjm1147.pdf .
This is a great comment and is being debated. Fusobacterium is a well known cause of invasive disease and much more common than we thought but the guidelines don't seem to consider it worthy of testing or treating. Dr Centor himself jumped into the discussion in 2015 saying it is hard to test for, lots of carrier states and not sure what to do with it, so use the Centor criteria and treat for strep. The IDA guidelines have not been updated for pharyngitis in 10 years but maybe they will weigh in soon?
I think Fusobacterium has near 100% penicillin sensitivity though - at least in the UK. This Daily Dose is interesting and timely as we currently have about a million kids a day attending my small rural ED in the UK due to parental concerns due to group A strep circulating more than usual for the time of year, a resulting uptick in invasive group A strep (no more than you'd expect for the burden in the community if that makes sense) and some very poor quality UK journalism putting the fear of god into every parent Over here, we mostly use FEVERPAIN though Centor is probably better validated. I advise my juniors to swab, and primary care follow up, and treat if they're sick, or have obvious scarlet fever. There's guidance awaited from NHS England which will be out later today I think... as we are struggling with regional supply issues with penicillin
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Emilio V., MD - December 8, 2022 7:04 AM
What about PCR testing for strep as a gold standard versus the antigen and throat culture approach?
Matia M. - December 8, 2022 11:12 AM
Currently the infectious disease guidelines say that throat culture is the gold standard for diagnosing strep throat. However, there is growing evidence that PCR tests has a similar sensitivity and specificity as throat culture for the diagnosis of GAS. PCR tests also has a faster turn around time that most throat cultures. I believe that one of the issues with the use of PCR testing is that it is not available in many clinical settings, although a review of the literature shows that it does appear to be a very good test. -Britt
Jeremy W. - December 8, 2022 9:22 AM
I am curious about any thoughts regarding an organism called Fusobacterium Necrophorum. Obviously, we aren't testing for this. However, there are a moderate amount of pubmed citations concerning its prevalence, and relevance, as a causative agent in a NOT small percentage of exudative pharyngitis, as well as its association with not-so-great problems like Lemierre's, bacteremia, or PTA, for example. To me, clinically, I feel like we mostly have a set of blinders on that says, "there IS NO OTHER BACTERIAL PATHOGEN BUT STREP that can produce pharyngitis--it is the ONLY THING I will consider" -- even though there are literally hundreds of diff bact in the oropharyngeal biome, at least ONE of which is documented to be a not trivial bacterial player in that space. If interested, here is an interesting article talking about it from 2017 in J Clin Microbiology--actually done right there in Los Angeles (Children's Hospital of Los Angeles)-- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5377842/pdf/zjm1147.pdf .
Mel H. - December 8, 2022 10:25 AM
This is a great comment and is being debated. Fusobacterium is a well known cause of invasive disease and much more common than we thought but the guidelines don't seem to consider it worthy of testing or treating. Dr Centor himself jumped into the discussion in 2015 saying it is hard to test for, lots of carrier states and not sure what to do with it, so use the Centor criteria and treat for strep. The IDA guidelines have not been updated for pharyngitis in 10 years but maybe they will weigh in soon?
https://www.consultant360.com/story/sore-throat-more-apt-be-fusobacterium-strep-young-people
Lou M. - December 9, 2022 3:33 AM
I think Fusobacterium has near 100% penicillin sensitivity though - at least in the UK. This Daily Dose is interesting and timely as we currently have about a million kids a day attending my small rural ED in the UK due to parental concerns due to group A strep circulating more than usual for the time of year, a resulting uptick in invasive group A strep (no more than you'd expect for the burden in the community if that makes sense) and some very poor quality UK journalism putting the fear of god into every parent Over here, we mostly use FEVERPAIN though Centor is probably better validated. I advise my juniors to swab, and primary care follow up, and treat if they're sick, or have obvious scarlet fever. There's guidance awaited from NHS England which will be out later today I think... as we are struggling with regional supply issues with penicillin