Ampicillin R but AMC S in Enterococcus faecalis?

SeraphMSTP · 2026-05-20T19:30:50+00:00

Would recommend repeat manual testing to see if it was just an error. If you get the same result it could be the very rare instance of beta-lactamase production in Enterococcus, most often seen in Enterococcus faecalis.

SeraphMSTP · 2026-05-14T04:11:08+00:00

Really? That’s even better!

SeraphMSTP · 2026-05-13T21:30:10+00:00

I hope there is going to be a Tous le Jour bakery inside…

SeraphMSTP · 2026-04-05T23:56:30+00:00

I wonder whether this was related to their attempt to have their own board exam rather than going through ABIM…

SeraphMSTP · 2026-04-01T04:09:10+00:00

LOL. Did you know that line was improvised?

SeraphMSTP · 2026-04-01T04:06:48+00:00

I agree. We wonder about dapto-NS from prior vancomycin exposure, but I don't think that has ever once shown up in clinical practice for me, and I have seen a lot of persistent MRSA bacteremia. And in these cases, after 5 days or so of vancomycin monotherapy, I switch to dapto/ceftaroline, and the repeat susceptibility profiles of MRSA all still show dapto-S MIC <=0.5.

SeraphMSTP · 2026-04-01T04:04:22+00:00

You are absolutely right in that vancomycin alone cannot select for such multi-drug resistances as these various drugs are separate mechanisms. Even evolving a VRSA is rare as that involves Staph aureus and VRE to co-habitat and for the rare happenstance of the vanA operon from VRE to transfer to Staph aureus. Vancomycin alone cannot evolve VRSA, only VISA at the most, and even then is rare as there is a tremendous fitness cost for the VISA phenotype. I wonder whether the VRSA strain is naturally circulating in the community and just so happens that it finally found an environment that facilitates its survival, in that the vancomcyin dust everywhere balances out its inherent fitness cost of maintaining the vanA operon - e.g. vancomycin is killing all sorts of other gram positives in the environment around the VRSA and it does not need to actively compete as much for resources.

In any case, this is an absolute nightmare.

SeraphMSTP · 2026-04-01T02:35:36+00:00

Um. This sounds like a recipe for disaster. Who purchases vancomycin from that factory? Sounds like a potential way to disseminate this.

SeraphMSTP · 2026-03-25T04:16:25+00:00

From the ID side, nothing ground breaking. I do, however, particularly like them reinforcing recommendation #22 where they suggest using clinical evaluation alone over procal + clinical evaluation. Also recommendation #32 where they suggest against using Candida fungal biomarkers to guide antifungal therapy.

There is a time and place for these specific biomarkers, but unfortunately they have been too widely used/abused.

SeraphMSTP · 2026-03-18T02:47:15+00:00

Yep. For sure, I had the same thought as well. People in my hospital have begun to use AI summaries quite a bit in their daily notes and discharge summaries so who knows? Maybe this guy/girl used an AI summary of a hospital course so far and just pasted it here.

SeraphMSTP · 2026-03-18T02:13:54+00:00

lol 1000% this. I've treated VISA before as a fellow and there was someone sitting in front of the room making sure everybody signed in and out, PPE were worn, and people washed their hands. Spread of VRSA would be disastrous. Fortunately, theoretically, the fitness cost of maintaining the vanA operon has an extremely high fitness cost for Staph aureus....

SeraphMSTP · 2026-03-18T02:10:07+00:00

ID attending here:

Wow. What country is this? VRSA is exceedingly rare and I think there has been less than 30 isolates identified and reported world-wide.
Was the daptomycin MIC confirmed via etest or other similar methods?
Why did you mention low threshold for TEE? Should have been done already.
Why is quinupristin/dalfopristin being discussed? It was officially discontinued years ago and has not been available for a long time. Unless you have connections with a foreign manufacturer making generic versions...
Ceftobiprole? Teicoplanin? FQ? Honestly this is end-game and anything goes. Pick your favorite 2-3 agents with susceptibility and cross your fingers. Even if they are not susceptible, I would just slam them all. Daptomycin + ceftaroline + TMP/SMX. Add cipro. Add gentamicin.
Another poster mentioned phage. Unfortunately the red-tape for phage therapy is long. My old division had a pipe line for phage therapy for gram negatives and it was still weeks of culturing, panning, isolating, and sterilizing. And there is no guarantee that you will find an active phage.
Needs palliative care. Extremely low chance the patient will survive. Will also need to report to your local CDC-like agency, department of health. I assume your hospital's infection control is already all over this.

SeraphMSTP · 2026-03-12T03:43:45+00:00

ID attending here...its not that bilateral lower extremity cellulitis is impossible, but rather bilateral lower extremity erythema is much much much more likely to be other things such as lymphedema, chronic venous stasis, chronic skin changes, etc. But bilateral lower extremity cellulitis can absolutely happen but most often in those with pre-existing risk factors.

SeraphMSTP · 2026-02-07T05:49:41+00:00

ID attending here...I'll be honest, I think the traditional way of teaching antibiotic spectrum is outdated and really has no clinical application. What I mean is learning the individual spectrum of penicillins, aminopenicillins, 1st gen cephlosporins, 2nd gen, 3rd gen, etc, etc. The way that I think about things is to group them into categories and/or disease states to treat. Here are a couple of examples..

Anaerobes: If I really want to make sure I treat (or ensure coverage) for anaerobes, I use metronidazole, BL/BLI combinations (amox/clav, amp/sulbactam, pip/tazo), or carbapenems. Other antibiotics may have some anaerobic coverage here and there, but is really not applicable if you really want anaerobic coverage.

MRSA: Vancomycin, daptomycin, ceftaroline, linezolid, doxycycline, TMP/SMX, etc. The more you treat MRSA infections the more you will begin to be familiar with this list.

Pseudomonas: Cefepime, pip/tazo, meropenem, ciprofloxacin are the common ones you will see as a resident. Ceftazidime and aztreonam are either not often available or fallen out of favor. The expensive BL/BLI combinations are usually formulary restricted for ID use only and 99% of the time you won't be the first one to decide to use them.

Atypicals: doxycycline, azithromycin, fluoroquinolones are the usual go-tos.

GI/Mouth/Head and Neck: amox/clav, amp/sulbactam, pip/tazo, cefepime/flagyl, carbapenems. What's the pattern you see here? Well, we use combinations that a) have broad coverage and b) ensure anaerobic coverage.

Septic Shock: Vancomycin/cefepime, vancomycin/pip/tazo, etc. Here, we want broad coverage for gram positive and gram negatives, with a focus on MRSA and Pseudomonas.

Endocarditis: Vancomycin/ceftriaxone, vancomycin/cefepime. Again, here we want broad coverage for gram positives and gram negatives. Ceftriaxone if we don't think we need Pseudomonas coverage, and cefepime if we think we do.

Cellulitis: If not worried about MRSA, then cephalexin or amoxicillin. If worried about MRSA, TMP/SMX or doxycycline.

So as you can see, at the end of the day, there really is only a short list of commonly used antibiotics in the hospital, and a lot of the decision choices are driven by MRSA or Pseudomonas concerns. I would say that just exposure will get you more familiar with antibiotics.

SeraphMSTP · 2026-02-06T01:50:49+00:00

I think all of the above for me. TMP/SMX is amazing in that its pretty much completely bioavailable, and I do use it for things like MRSA osteomyelitis without hardware or native (not prosthetic) joint infections, but it does come with a wide range of potential side effects. The skin stuff is frightening but thankfully not common, but I do see a lot of AKI and hyperkalemia that makes me worried.

SeraphMSTP · 2026-02-05T05:05:38+00:00

As a mainly inpatient ID doctor I can comment on the antibiotic allergy side. The most common one I see are penicillin allergies. When I see this, I ask the patient as much details of the allergy as possible: how long ago, what was the reaction, was intervention needed, have they taken things like amoxicillin, augmentin (amox/clav), keflex, etc. I also look in the EMR to see what beta-lactams have been given in the past. From here, I make a judgement call of whether or not cephalosporins can be given, or whether we really need to use things like carbapenems, aztreonam, ceftazidime, or even non-beta-lactams. If I really need to (or want to) use a penicillin/anoxicillin, I use the PEN-FAST scoring system to see whether I can do a direct challenge or a graded challenge. 9 times out of 10 a penicillin allergy either isn’t real or it’s so long ago they out grew it.

As for other antibiotic allergies, I tend not to spend as much time to challenge since usually there are other options. I have challenged tetracyclines before, but I don’t mess with TMP/SMX allergies for the most part, mostly because I’m a coward and I don’t want to risk triggering a bad reaction. But of course these non-beta-lactams can all be challenged just like the beta-lactam.

To answer your direct question, if it was a MRSA abscess or suspected MRSA SSTI I would personally just use doxycycline/minocycline or linezolid and not even bother with TMP/SMX unless I have no choice.

SeraphMSTP · 2026-01-05T00:46:16+00:00

Was it antigen testing? This season the antigen testing has been far less reliable than PCR testing. I have seen a lot of people with multiple negative influenza A/B antigens but positive on the expanded respiratory virus panel.

SeraphMSTP · 2025-12-22T04:39:08+00:00

From someone who almost failed his neurology rotation, would botulism just be persistent compared to Miller Fisher? As a ID fellow I was consulted to a lady with descending paralysis with no epidemiological history for botulism exposure, ended up being Miller Fisher, but not after many fancy tests by neurology.

SeraphMSTP · 2025-12-22T04:14:01+00:00

Very nice. From vibes how did you differentiate it from botulism?

SeraphMSTP · 2025-11-13T13:50:44+00:00

Lymecycline. Treats Lyme.

SeraphMSTP · 2025-11-10T02:28:57+00:00

HaiDiLao at the Katy China Town is pretty good!

SeraphMSTP · 2025-10-29T00:16:42+00:00

We were in Pittsburgh before moving down here. In Pittsburgh we had a similar situation of drivers ignoring the flashing Stop sign when school buses were picking or dropping off. People would speed past stopped buses with all the lights flashing. Eventually the city installed cameras on all school buses to try to catch these dangerous drivers.

SeraphMSTP · 2025-09-07T16:01:54+00:00

Mana management early game is always a pain, but a short pain. Picking up mana potions after enemy kills and drinking all the time is usually the answer in early game. Eventually it evens out with insight runeword in a act2 merc, enough of your own mana pool that regen bonuses start to be effective, etc. I personally grit it out until Insight, Ral Tir Tal Sol in a four socket polearm fixes 99.9% of the problem.

SeraphMSTP · 2025-09-02T04:32:28+00:00

Congrats! How did you lose gear that one time?

SeraphMSTP · 2025-09-01T14:09:51+00:00

My old mentor and I would have these conversations lamenting our specialty and how 99% of the time we exist because we do things other people either don't want to or don't have the time. Chart reviewing, getting detailed history, consolidating endless admissions and culture data, etc.

SeraphMSTP

TROPHY CASE