Stanford Antimicrobial Safety & Sustainability Program

📚 References:

Berbari et al., IDSA Osteomyelitis Guidelines (2015) — PMID: 26229122

IWGDF/IDSA 2023 Diabetes‑related Foot Infection Guidelines — PMID: 37779323

⚠️ Start empiric antibiotics immediately if the patient is:

-Hemodynamically unstable
-Showing signs of impending sepsis
-Having neurologic compromise
-Or has a superimposed acute infection

In these cases ➜ urgent surgical consultation should also be considered.

✅ A: Consider holding antibiotics before a diagnostic procedure to improve culture yield IF:

🚫 No evidence of impending sepsis or hemodynamic instability
🚫 No neurologic compromise (for vertebral osteomyelitis)
🚫 No superimposed acute infection (e.g., overlying SSTI)

🌟 ABX Pearl of the Day
❓ Q: In a patient with suspected osteomyelitis, should I start empiric antibiotics or withhold antibiotics to improve diagnostic yield?
#IDsky #medsky #meded #pharmsky #skyRX

💡 Take-home:
If you see E. gallinarum, think:
➡️ Intrinsic vancomycin resistance (vanC)
➡️ Usually ampicillin susceptible
➡️ Pip/tazo likely active but broader than necessary

🔎 These principles also apply to other less common enterococcal species:

• Enterococcus casseliflavus
• Enterococcus raffinosus

🧪 Diagnostic pearl

❗ vanC is NOT detected by available rapid diagnostic tests (RDTs detect vanA and vanB genes only)

Most microbiology labs will automatically report E. gallinarum as vancomycin resistant due to known intrinsic resistance.

🧬 Why is it vancomycin resistant?

Resistance is modulated by the vanC phenotype, which is chromosomally encoded.

• Typically confers lower-level resistance (MIC 4–32 mg/L)
• 🚫 vancomycin should be avoided for treatment

A: ⚠️ E. gallinarum is intrinsically vancomycin resistant.

👉 However, these organisms are typically ampicillin susceptible, so they are likely covered empirically by pip/tazo.

💊 Linezolid is not indicated empirically unless the patient is intolerant to penicillins.

🌟 ABX Pearl of the Day: Enterococcus gallinarum in Blood Cultures

❓ Q: My patient’s blood cultures are growing Enterococcus gallinarum with susceptibilities pending.
They’re on empiric vancomycin + piperacillin/tazobactam.
Is this appropriate coverage?

#IDsky #medsky #meded #pharmsky #skyRX

📚 References: Keller EC et al. Cleve Clin J Med. 2012. PMID: 22854433
Hirschmann JV et al. J Am Acad Dermatol. 2012. PMID: 22794815
Rzepecki AK, Blasiak R. Curr Geri Rep. 2018. DOI: 10.1007/s13670-018-0257-x

🔍 Notable mimics of cellulitis include (but are not limited to):
- Stasis dermatitis
- Lymphedema
- Contact dermatitis
- Lipodermatosclerosis
- Eosinophilic cellulitis
- Deep vein thrombosis

💡 A: Cellulitis can be tricky to diagnose due to other clinical syndromes that can present in a similar way.

👣In patients with bilateral lower extremity erythema, alternative etiologies should be explored, as cellulitis is unlikely to present this way. In fact, it's almost never due to infection.

🌟 ABX Pearl of the Day: bilateral LE erythema = cellulitis?

❓ Q: What are common mimics of cellulitis?

#IDsky #medsky #meded #pharmsky #skyRX

References:
1. NCCN Guidelines Prevention and Treatment of Cancer Related Infections v3.2024
2. ECIL-10 Guidelines
3. Elting, et al. J. Clin Oncol. 2000; PMID: 11054443
4. SHC FN Guidelines med.stanford.edu/content/dam/...

TL;DR:
🔥 Persistent fever in stable FN ≠ automatic escalation to carbapenems
💡 Stick with cefepime, keep looking for the cause, escalate thoughtfully

🔍 Instead of escalating antibiotics:
-Continue diagnostic workup for an infectious source
-Consider non‑bacterial causes (e.g., fungal infection, drug fever)
-Consider ID consult if persistently febrile without a clear diagnosis or concern for non-bacterial/opportunistic infection.

⏳ Why?
Time to defervescence on appropriate empiric therapy can be 2–7 days (median ~5 days).
Persistent fever ≠ treatment failure³

✅ A: In stable FN patients with persistent fever of unknown origin, current NCCN¹ and ECIL‑10² guidelines do NOT recommend changing empiric Gram‑negative coverage.

🌟 ABX Pearl of the Day:

❓ Q: My patient with febrile neutropenia (FN*) on IV cefepime is hemodynamically stable but continues to have fevers. Do we need to switch empiric antibiotics to IV meropenem?

#IDsky #medsky #meded #pharmsky #skyRX #AMSsky

Important:
If a new fever* develops after de‑escalation or discontinuation, empiric IV antibiotics should be restarted and a full ID workup initiated.

🔗SHC FN Guidelines med.stanford.edu/content/dam/...

📏 This practice aligns with:

NCCN Guidelines
ECIL Guidelines

⚠️ Caveat: The degree of applicability to allogeneic HSCT recipients is uncertain because they were under‑represented in the trial.

The evidence:
The How Long Study (open‑label RCT) showed that stopping empiric antimicrobials after 72 hours without fevers in hematologic malignancy patients with FN led to:

🔻 Significantly less antibiotic exposure
❌ No increase in mortality or fever recurrence
(How Long Trial, 2017)

✅ A: Data support early discontinuation of empiric IV antibiotics at 72 hours in patients with FN who have clinical recovery and fever resolution — regardless of current ANC.

🌟 ABX Pearl of the Day:

❓ Q: My patient with febrile neutropenia (FN*) has been afebrile for 72 hours, is asymptomatic, and we haven’t found an obvious infectious source.
How long should I continue cefepime?

#IDsky #medsky #meded #pharmsky #skyRX #AMSsky

🧠 TL;DR:
Most candiduria = colonization.
Fix the risk factors, don’t reflexively prescribe antifungals.
Treat only when symptomatic or high‑risk.

🔹 When treatment is indicated:
If symptomatic, fluconazole is the drug of choice for patients with Candida UTI.
Echinocandins (e.g., caspofungin) do not reach urine concentrations adequate for treatment.
(PMID: 21498839)

🔹 When not to treat:
Treatment with antifungal agents is NOT recommended unless the patient is clearly symptomatic or at high risk for dissemination — including neutropenic patients and those who will undergo urologic manipulation.
(PMID: 26679628)

🌟 ABX Pearl of the Day:

❓Q: Candida in the urine? Should you treat?

✅ A: Usually not. Candiduria almost always reflects colonization, not infx. It should prompt elimination of risk factors- e.g., d/c indwelling catheters rather than antifungal tx🚫

#IDsky #medsky #meded #pharmsky #skyRX #AMSsky

Even in severely immunocompromised pts, Candida pneumonia is exceedingly rare (0.2–0.4%) & usually linked to hematogenous spread (PMID: 8502166).