Carley’s note: Dana DelTufo, PharmD, BCPS is back at it again to torture you all educate you about a difficult infectious disease topic…osteomyelitis! In case you haven’t met her yet… Dr. DelTufo 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!

Let’s talk about osteomyelitis, which is the infection that says, “I could’ve just been a skin abscess, but I’m feeling extra today.” This is what happens when bacteria get ambitious and decide to colonize your skeleton like it’s the Oregon Trail. Only, instead of settlers, it’s Staph aureus, and instead of wagons, it’s biofilm. So buckle up, if you like long courses of antibiotics, MRSA, and radiology reports that might as well be in Latin, you’re in the right place.

What the Heck Is Osteomyelitis?

Bone infection. Not cute.
Most common culprit? Staph aureus. Bonus points if it’s MRSA, because of course it is.
Can be acute (new mischief) or chronic (lingering nightmare).
Requires weeks of IV antibiotics, maybe surgery, definitely drama.
You’ll need labs, imaging, cultures, and a good therapist (for you, not the patient).

How Does This Happen?

Osteomyelitis is basically just a bacterial field trip gone wrong. Here’s how they get there:

Hematogenous Spread – Bacteria catch a ride in the bloodstream like it’s an Uber to the femur. Common in kids and the elderly.
Contiguous Spread – That diabetic foot ulcer that’s been ignored for 8 months? Yeah, it finally RSVP’d to the bone.
Direct Inoculation – Trauma, orthopedic surgery, open fractures, or that one time someone thought “cleaning the wound with motor oil” was a good idea.

Once inside, the bacteria throw a biofilm rave, shut down the bone’s defenses, and make themselves at home. Ever tried evicting a tenant with squatters’ rights? It’s like that. But in your spine.

I know this is what you want to do right now, but we haven’t even gotten started yet. (Image)

Who’s on the VIP List?

Diabetics (especially with zero foot sensation and questionable shoe choices)
Patients with hardware (prosthetic joints, rods, you name it)
People with crap circulation (PVD, dialysis patients, the eternally cold, individuals with sickle cell disease)
IV drug users (because bones apparently looked like a fun place to inject by proxy)

Oh…you’re not laughing? Okay, moving on. Tough crowd. (Image)

Clinical Clues: Red, Swollen, Angry Bone Vibes

🔴 Localized pain – Think “hurts when I move it, hurts when I don’t.” 
🔥 Fever – Optional, because bacteria love to keep things unpredictable. 
🌋 Redness/swelling – Cellulitis’ evil twin. 
🚿 Drainage – Especially in chronic osteo. Might look like pus. Might smell like regret.

Labs and diagnostics you'll pretend aren’t as bad as they are:

↑ WBC – Classic.
↑ ESR/CRP – Because inflammation is a lifestyle.
💉 Positive blood cultures – Sometimes! Don’t get too excited.
🧲 MRI – The gold standard because X-rays are like “I’ll show something… in a few weeks maybe.” There is typically a lag of about 10-14 days. Don’t wait by the phone.

Bugs and Drugs: AKA “Which IV Do We Hang Today?”

The Greatest Hits:

Staph aureus (the Beyoncé of bone bugs)
MRSA (because life isn’t hard enough)
Strep species
Pseudomonas (in IV drug users or diabetic feet that have been marinating)
Enteric Gram-negatives
Salmonella (look out for this in your sickle cell patients!)
Anaerobes (you’ll smell them before you see them)

Seriously though, we’re gonna need a magic spell to get rid of this infection! (Image)

Empiric Antibiotic Regimen:

Vancomycin (because it’s not osteo without it)

++PLUS++

Something Gram-negative friendly like cefepime, ceftriaxone, or piperacillin-tazobactam (Zosyn) (for when you really want to cover the whole periodic table)
Feeling extra polymicrobial? Add metronidazole or just go all in with Zosyn and question your life choices later.

Key Principles

Start empiric antibiotic(s) after cultures unless the patient is already septic. 
Target high bone penetration and biofilm activity when hardware is involved.

Duration?

4-6 weeks minimum, and that’s if you’re lucky.
Chronic cases? Sit tight—you're looking at 6+ weeks, maybe lifelong suppression if that metal’s staying in there.

And yes, oral step-down might be on the table, but only if:

The bug is pansensitive,
The patient is reliable,
And ID gives it a reluctant nod.

Pathogen-Directed Therapy

Oral Step-Down Therapy Evidence

As an Antimicrobial Stewardship Specialist, it would be borderline sacrilegious not to talk about the OVIVA trial since it basically rewrote the gospel on bone and joint infections.

The Oral versus Intravenous Antibiotics for Bone and Joint Infection (OVIVA) trial, published by Ho-Kwong Li et al (NEJM, 2019) tackled a long-standing dogma in infectious disease: that bone and joint infections need 6+ weeks of IV antibiotics. Researchers randomized over 1,000 patients with confirmed bone or joint infections to receive either standard IV antibiotics for 6 weeks or switch to oral therapy within 7 days. The result? Oral therapy was non-inferior to IV in terms of treatment failure at 1 year (13.2% oral vs. 14.6% IV), meaning patients did just as well without the PICC lines and infusion pumps.

Why it matters: This is a big deal, especially for antimicrobial stewardship and outpatient care. Oral regimens were easier, cheaper, and came with fewer line-related complications (like bloodstream infections and thrombosis). The study included a wide range of infections (including prosthetic joint infections), and the oral regimens were selected based on susceptibility and good oral bioavailability (think fluoroquinolones, rifampin, linezolid, etc.). Bottom line: in stable patients with bone or joint infections and good oral options, early switch to oral antibiotics is not just safe — it’s smart, like you!

Look at us chipping away at osteomyelitis (no pun intended, or maybe there is). (Image)

Oral Step-Down Therapy Options

Linezolid → reliable MRSA oral option, but monitor for myelosuppression and serotonin syndrome. Super conveniently, a 1:1 IV:PO conversion.
Fluoroquinolones (cipro, levo) → excellent bone penetration; resistance and QT prolongation risks. 
Clindamycin → good for susceptible MSSA/MRSA; beware GI upset and C. diff. Remember, just one dose of clindamycin puts your patient at risk for C. diff! Be mindful of your local antibiogram because it may suck at covering some common Gram-positive bugs.
TMP/SMX → decent bone penetration; often combined with rifampin for biofilm-related Staph.

Biofilm Considerations

Rifampin = MVP when hardware is present and Staph is cultured.
- Start after source control and after bloodstream clearance. 
- Check for CYP interactions (warfarin, antiepileptics, DOACs).

Choose Your Own Nightmare: Special Cases Edition

Diabetic Foot Osteomyelitis

Polymicrobial dumpster fire.
Start with broad-spectrum everything. Narrow once you tame the chaos.
Usually needs debridement, wound care, and probably new shoes.

Vertebral Osteomyelitis

Patient says: “My back hurts.” You say: “That’s normal.”
MRI says: “Surprise, it’s osteo.”
Can be Staph, but don’t forget TB if they’ve traveled, coughed, or just have bad luck.

Hardware-Associated

Because bacteria LOVE prosthetics.
Surgery + long-term antibiotics is your only hope.
Rifampin may help nuke biofilms, but only when used with other agents. Never solo, unless you’re trying to breed resistance in a petri dish.

PharmD Pro Tips 💊

🧠 Vanc kinetics = Your moment to shine. Get that AUC/MIC on point or forever hold your peace. 
🧪 Culture the bone. Not the drainage. Not the toe jam. The bone. 
📆 Track antibiotic start dates. Because a “4-week course” that lasts 87 days isn’t cute. 
📉 Monitor CRP/ESR weekly. Not diagnostic, but if it’s trending down, your patient might be too.
And yes, always call ID. Osteo is not a DIY infection. Unless your idea of DIY includes necrosis and malpractice.

You showing up to rounds tomorrow ready to diagnose everyone with osteo. Please don’t, though. (Image)

TL;DR of the TL;DR (for your pre-rounding brain)

Osteomyelitis = infected bone. Usually caused by Staph, treated with IV antibiotics for 4-6 weeks, and best managed with ID on speed dial. MRI is your bestie, oral step-down is a maybe, and CRP is your mood ring for progress.

Final TL;DR Summary

Treating osteomyelitis is like babysitting a gremlin. It looks like you’ve got it under control, but blink once and suddenly it’s wearing hardware, leaking pus, and asking for a PICC line.

So take a deep breath, hang your vancomycin, and remember: bones may be hard, but osteo is harder.

When Bones Decide to Rot: A Pharmacist's Guide to Osteomyelitis