Category: Antibiotics

Doom and gloom from the Netherlands regarding antibiotic resistance in E. coli.  Although they focus on the resistance rates to fluoroquinolones, the more interesting take-home point from this article is the risk factors described for polypharmacy resistance.

Almost a year old now, but it’s been dredged up for Journal Club (spoiler alert: the next two days might have something in common with vis-a-vis dredging).

Small study randomizing skin abscess to placebo vs. TMP-SMX after incision and drainage in children.  I think it’s a fair article with decent external validity, as I would say this directly addresses the practice pattern of pediatric emergency physicians, let alone community pediatricians.  The real issue is statistical power for their secondary endpoint and some minor differences between their two groups.  Treatment failures comparing placebo and TMP-SMX are identical – which just goes to show you that the I&D really is the most important element of treating abscesses.  They do a lot of packing!  I suppose I’m almost more surprised there isn’t more packing, since that’s the commonly accepted practice, but I digress.

The only fire remaining in their argument is that antibiotics will decrease recurrent abscesses.  And, I am willing to give them that – although, I really expect, if they had a longer follow-up period, a lot of those abscesses would return after the antibiotics were stopped because the environment requires eradication.  However, there’s a significant difference in the number of each group with a history of recurrent abscesses favoring the TMP-SMX group, which might explain the magnitude of their difference in recurrent lesions within 10 days.

Too small a study to change our practice – although, our practice probably should never have changed from not treating abscesses with antibiotics in the first place.

http://www.ncbi.nlm.nih.gov/pubmed/19409657

More public health doom and gloom from the infectious disease world – multiple bacterial found carrying stable and transmissible plasmids for the NDM-1 gene, a form of beta-lactamase that endows bacteria with carbapenem resistance.  In the sewage.  And in the drinking water.

These are two articles coming to us from January’s NEJM – one from Pittsburgh and one from Finland.  For a ridiculously prevalent disease managed daily in the ambulatory setting by thousands of providers across the world, we really don’t know what we’re doing.  Firstly, we know there are bacteria in the middle ear – plenty of studies have aspirated out a variety of pathogens.  Secondly, undertreated AOM may lead to suppurative complications – the surgical emergency of mastoiditis.  Finally, however, we also know the natural history of AOM is to resolve without intervention and treatment in most cases.

The commentary accompanying these articles seemed to think these two studies tilted the balance in favor of routine antibiotic use for AOM.  And, you can read the articles in that fashion – the Finnish article makes an argument that by their standard of care, the placebo group had 45% treatment failure and required antibiotic rescue 30% of the time.  However, I read the article and their definitions of treatment failure are, for the most part, not clinically relevant.  A red ear that still looks red on day three does not predict much – and, actually, a lot of their primary outcome measures were not statistically significant until they added in the 30% they used rescue treatment on to boost their definition of treatment failure.  So, this study doesn’t tell much much – except that Augmentin causes diarrhea 40% of the time.

The Pittsburgh study reads much more straightforward and, partially, justifies my criticism of the Finnish study.  By day 7, 80% of their Augmentin group had symptom improvement compared to 74% of their placebo group.  However, the ears still looked terrible in the placebo group – but, obviously, weren’t correlating with symptoms.  So, is it clinically relevant to define treatment failure based on the appearance of the ear?  I would say that improvement in symptoms is the appropriate measure of clinical cure – and in that respect, the 80% vs 74% numbers match up better with previously published literature.

To me, these articles don’t help.  I don’t necessarily mind the AAP recommendations of treating AOM with antibiotics under a year of age – although, really, after their third set of immunizations, it’s not as though this is going to be a nidus for SBI.  Clearly, antibiotics offer some advantage – but not to everyone.  When I have a three year-old I have to hogtie to get a one-second glimpse at a red TM, how do I know whether this is a patient whose AOM will resolve on its own, or whether he falls into the subset of patients who will derive benefit from antibiotics?  And, is that 6% absolute difference in clinical outcome worth giving 40% of children horrible diarrhea (not that anyone uses Augmentin first-line for AOM, anyway).  With the NNT with antibiotics to prevent one case of mastoiditis estimated at 4100 from cohort data from the United Kingdom, that’s a lot of useless (and harmful) antibiotic prescriptions.  If we want to reduce the amount of antibiotic resistance in this country, I think these studies support a conservative non-antibiotic strategy initially in appropriately selected patients.

http://www.ncbi.nlm.nih.gov/pubmed/21226577
http://www.ncbi.nlm.nih.gov/pubmed/21226576

Addendum 5/11: Scott Weingart & David Newman did a bit of a rant on this topic on the most recent EM:RAP where they attacked the Pittsburgh article specifically regarding result reporting integrity.  Dr. Newman delved into far more detail regarding the multiple primary outcomes listed and found the original research protocol listed only time to resolution of symptoms as the primary outcome – which was statistically equivalent between the two groups.  He and Dr. Weingart seem to suggest there was not sufficient editorial oversight regarding the publication of this article due to these flaws, and that the author’s conclusions are suspect to the point of disingenuous.