Steph’s Note: Dana DelTufo, PharmD, BCPS is the Antimicrobial Stewardship Specialist at Meritus Medical Center in Hagerstown, Maryland. She completed her PGY-1 at the same hospital in 2022, proving she can survive both a residency and vancomycin consults without becoming resistant to stress. Dana earned her PharmD from Notre Dame of Maryland University School of Pharmacy in Baltimore back in 2021 (Go Gators!). Her professional passions include medication safety, cardiology, and infectious diseases, which basically means she’s in a long-term relationship with guidelines and antibiograms. When she’s not optimizing antibiotics, you’ll find her cooking, hiking, photographing the great outdoors, or nose-deep in a good book (no package inserts allowed). Say hi to Dana on LinkedIn or tweet her @DDelTufoRx!

Ah, the heart. That tireless, lovable, four-chambered organ that pumps life through your veins and awkwardly flutters when you unexpectedly run into your crush at CVS. But sometimes, your heart can get a little too much attention from the wrong kind of admirers.

We're talking about endocarditis…or when bacteria decide to Airbnb your heart valves and never leave. The tl;dr warning: endocarditis will clog your brain before your arteries. It’s a stroke of complexity!

Let’s break it down so your brain doesn’t embolize from information overload.

The Basics (aka What Is Endocarditis?)

Endocarditis = inflammation of the inner lining of the heart (endocardium), usually caused by an infection. It’s most commonly bacterial, but fungi and other microscopic freeloaders can throw the party. Left untreated, it’s bad news bears. Think: heart failure, stroke, and surprise emboli.

Imagine your heart valves as pristine, buttery croissants. Endocarditis is what happens when bacteria smear moldy peanut butter on them and call it a snack.

Technically, it’s an infection of the endocardial surface, which includes your heart valves. Bacteria (or fungi) get into your bloodstream via things like IV drug use, dental work, or a rogue skin infection and decide to colonize your valves. And no, they do not pay rent.

Who’s at Risk?

Endocarditis doesn’t just pop in on anyone like your nosy neighbor Karen. It has a type. Risk factors include:

Prosthetic heart valves (bacteria love the high-tech stuff)
Congenital heart defects (especially with turbulent flow)
Previous endocarditis (because once wasn’t enough)
IV drug use (aka shooting up more than insulin)
Poor dental hygiene (floss, people. Just floss.)

Also, let’s pour one out for anyone who’s had invasive procedures (like central lines or valve surgeries). You’re on the list too.

Bugs That Love Hugs (With Your Heart)

Some of the usual microbial suspects include…

Staphylococcus aureus (especially in IV drug users; this dude is aggressive and likes the tricuspid valve)
Streptococcus viridans (your mouth's shady roommate who often shows up post-dental work)
Enterococcus (likes to hitchhike from the gut or genitourinary tract)
HACEK organisms (fastidious gram-negatives who are basically the hipsters of endocarditis)
- Haemophilus,
- Aggregatibacter,
- Cardiobacterium,
- Eikenella,and
- Kingella
Fungi (Candida, Aspergillus which is typically rare, but deadly. Basically the final boss of endocarditis.)

Symptoms of Endocarditis: The “Weirdly Vague but Concerning” Collection

Endocarditis can be sneakier than your ex stalking your Instagram. It starts all chill with the following:

Fever (duh)
Fatigue
Night sweats
Weight loss

But then it starts throwing curveballs:

New or changing heart murmur
Splinter hemorrhages (tiny streaks in your fingernails)
Janeway lesions (painless palm/sole spots, aka the introverts)
Osler nodes (painful little lumps on fingers/toes, aka the drama queens)
Roth spots (retinal hemorrhages with white centers that are fancy but ominous)

Also, emboli can fly off and cause strokes, kidney infarcts, or even weird spleen pain. Because why not?

Diagnosing Endocarditis: Not Just Vibes

We don’t just go, “Hmm, sounds like endocarditis” and toss antibiotics at it (although tempting). Here’s how the pros do it:

Duke Criteria (yes, like the university where smart stuff happens)

No, you can’t trade 2 Osler nodes for a Duke basketball ticket. I checked.

Endocarditis Treatment: Kill It with Drugs (Not Literally, Please)

For treatment, you’re looking at long-term IV antibiotics. Like, 4-6 weeks long. This isn’t a “pop a Z-pack and bounce” situation.

Unless this is something you do literally every day, I highly suggest you always double check the treatment guidelines. Drug choice and duration depends on multiple factors, including the invading bacteria and susceptibilities, whether the bacteria have set up shop on a native versus a prosthetic valve, and a patient’s allergies. It’s not a one size fits all kinda thing. That being said, some common regimens include…

Native valve, Strep viridans: Penicillin G or ceftriaxone ± gentamicin
Staph aureus (MSSA): Nafcillin or oxacillin ± rifampin (if prosthetic valve)
MRSA: Vancomycin (because obviously)
Enterococcus: Ampicillin + gentamicin or ceftriaxone

Let’s talk more in depth about how to treat these little buggers. Buckle up!

1. Streptococcus viridans (Native Valve)

Bug Profile: Your run-of-the-mill alpha-hemolytic freeloaders from the mouth. Shows up after dental work or when flossing becomes "aspirational."

🥇 First-Line: Penicillin G

Drug Class: Beta-lactam (OG edition)
Dose: 12-18 million units/day IV (q4–6h or continuous because nurses looove hanging piggybacks at 3 am) × 4 weeks
Fun Fact: If MIC ≤0.12 mcg/mL, you're golden. If >0.12, consider more aggressive combo therapy because things just got serious.
Side Effects: Seizures (at high doses), neutropenia, allergic reactions (because why wouldn’t someone be allergic to the first antibiotic ever invented?)
Monitoring: CBC weekly, SCr/BUN (just in case the kidneys want to make things interesting)

Alternate Therapy: Ceftriaxone

Dose: 2 g IV once daily × 4 weeks (or 2 weeks with gentamicin if you're feeling spicy)
Why?: Once-daily dosing and it doesn’t ask much of you outside of love, respect, and occasional LFTs.
Side Effects: Biliary sludging (aka pseudolithiasis), diarrhea, “cephalosporin-style” rash

➕ Optional Gentle Giant: Gentamicin (aka "the synergy whisperer")

Dose: 3 mg/kg/day IV divided as q8h × 2 weeks
Purpose: For synergy, because Strep needs a chaperone to die properly
Side Effects: Nephrotoxicity, ototoxicity, a sense of dread every time you check troughs
Monitoring: Peak/trough (because guessing is frowned upon), renal function, maybe baseline audiology if you’re really Type A

2. Staphylococcus aureus: MSSA

Bug Profile: Professional biofilm builder and general menace. Always brings the drama.

🥇 First-Line: Nafcillin or Oxacillin

Class: Penicillinase-resistant penicillins (aka “the beefed-up penicillins”)
Dose: 12 g/day IV in divided doses (q4h or continuous) × 6 weeks
Side Effects:

Oxacillin = Liver says “ouch”
Nafcillin = Kidneys say “maybe”
Both = Neutrophils take a vacation

Monitoring:

CBC weekly (neutrophils are shy)
LFTs (esp. oxacillin)
SCr/BUN

➕ Bonus Round for Prosthetic Valves: Rifampin

Rifampin’s orange Fanta effect on urine (and other bodily fluids). (Image)

Dose: 300 mg PO/IV q8h × ≥6 weeks (but only start after bacteremia is cleared because this drug doesn’t play well with friends if there’s still active infection)
Purpose: Busts up biofilms like a boss. Penetrates foreign material. Also turns your patient’s urine, saliva, tears, and sweat the color of Fanta.
Side Effects: Hepatotoxicity, many, many drug interactions (CYP450 = 🔥), and enough orange staining to confuse the laundry staff.
Monitoring: LFTs weekly, drug-drug interactions (warfarin, antiepileptics, hormonal birth control…rifampin doesn’t care, it just burns bridges)

3. Staphylococcus aureus: MRSA

Bug Profile: Methicillin-resistant and emotionally unavailable.

🥇 First-Line: Vancomycin

Dose: 15–20 mg/kg IV q8–12h (based on actual body weight because accuracy matters, folks)
Target: AUC/MIC 400–600. Yes, we said AUC, not “just get the trough and pray.”
Side Effects:

Nephrotoxicity (especially with piperacillin/tazobactam #nephrotoxicpowercouple)
Vancomycin Infusion Reaction (formerly known as Red Man Syndrome, which is not a true allergy, just a histamine rave)
Neutropenia (because white cells have a flair for drama too)

Monitoring:

AUC-based dosing or Bayesian magic
SCr/BUN q48–72h (more frequently if ICU vibes are present)
Weekly CBC

Backup Plan (if vanc MIC ≥1 or your patient is a "vanc hater"): Daptomycin

Dose: 8–10 mg/kg IV daily
Class: Lipopeptide
Use: Excellent for right-sided or prosthetic valve cases. FYI, not for pneumonia (it gets surfactant-blocked like it's trying to get into a club with sneakers)
Side Effects: Myopathy, rhabdo, eosinophilic pneumonia (because apparently lungs get involved anyway)
Monitoring:

CPK weekly (and maybe a statin holiday for the patient)
Renal function
Muscle pain = a red flag

4. Enterococcus faecalis/faecium

Bug Profile: Stubborn. Resistant. A real piece of work. Comes in pairs (like the kidneys it wants to ruin).

🥇 First-Line: Ampicillin + Gentamicin

Ampicillin Dose: 2 g IV q4h × 4–6 weeks
Gentamicin: 3 mg/kg/day IV divided q8h (for synergy which is not to be confused with torture)
Why?: Enterococcus needs a 1-2 punch. Monotherapy just makes it stronger.
Side Effects: Gentamicin = “pick your organ: ears or kidneys?”
Monitoring:

Gent troughs <1 mcg/mL
SCr/BUN every few days (or every hour, depending on how nervous you are…kidding!)
Audiology, if extended treatment (especially if you don't want your patient to hate you later)

Renal Friendly Alternative: Ampicillin + Ceftriaxone

Doses: Ampicillin 2 g IV q4h + Ceftriaxone 2 g IV q12h × 6 weeks
Why?: If the kidneys tap out or if the bug laughs at aminoglycosides (i.e., high-level resistance), this beta-lactam tag team targets multiple PBPs like a buddy cop film.
Side Effects: Generally well-tolerated. Avoids the gentaminoglyco-nightmare.
Monitoring: CBC, renal function, C. diff risk (because...ceftriaxone)

Also, surgery enters the chat if there’s:

Heart failure
Persistent infection
Large vegetations
Embolic events
Prosthetic valve involvement

Endocarditis Prevention: Don't Invite the Germs In

Good dental hygiene: We said it before, we’ll say it again. Floss.
Prophylactic antibiotics for high-risk patients before dental or respiratory procedures.
Don’t use dirty needles (or any needles recreationally, ideally).
Fix those heart valves if they’re leaky or flappy in a bad way.

Final Thoughts on Endocarditis: Be Kind to Your Valves

Endocarditis isn’t just an annoying infection, it’s a full-blown cardiovascular emergency. If left untreated, it can wreck your valves, throw emboli like it’s dodgeball, and end with sepsis or death.

So keep your heart clean, your dental checkups regular, and if your patient’s got fever + murmur + weird skin stuff? Think endocarditis. Or at least don’t ignore it like it’s a sketchy Craigslist listing.

The Pharmacist's Heart to Heart on Endocarditis