VUSMLE Vault←All guides
USMLE Vault Β· Step 1 Β· Tier list 4 of 6

The USMLE microbiology tier list

For IMGs drowning in bugs: the 1 resource that makes them stick, and what to skip.

By Dr. Marish Asudani Β· Published

What is the best resource for USMLE microbiology?

Sketchy Micro is S tier: for micro, nothing else comes close. Mehlman micro is A. Dirty Medicine micro and the First Aid micro pages with the FA Guide MCQs are B. Boards & Beyond, Pixorize and AJmonics micro are C. Ninja Nerd micro is D, and Kaplan is F.

Read this firstBoards & Beyond, Kaplan, Sketchy, Pixorize, First Aid, and the free playlists. Micro is pure volume: dozens of bugs that blur together. The resource that wins is the one that makes them stick.

Every name below opens it. Here is how to read the tiers:

4

Tier list 4 of 6Micro resources

9 resources, 6 tiers. Tap any name to open it.

SFor micro especially, nothing else comes close. About 85 bugs in 6 days, around 20 a day: watch, recall out loud, re-watch the gaps, read the PDF, then that day's MCQs the same night.

"Just doing the Sketchy PDF and not watching the videos. That is the stupidest thing that students ever do, or just doing the First Aid for Microbiology and not using Sketchy."

sketchy.com ↗ Β· Micro by system β†’

↓

Top to bottomThe rest of the micro list, and why

Free playlist

AMehlman Β· Microbiology

Why: short, dense and free, and he teaches micro the way the examiner asks it. For Step 3, his micro and pharm playlists are the ones I use, with First Aid open at the same time. ▶Mehlman Β· Microbiology playlistFree
Free playlist

BDirty Medicine Β· Microbiology

Why: the one to open when a single bug won't click. ▶Dirty Medicine Β· MicrobiologyPlaylist
Same night as Sketchy

BFirst Aid micro pages + the FA Guide micro MCQs

Why: same-night MCQs for each Sketchy day, pp. 132–173. Read TB, COVID, HIV, Bunyaviruses and malaria from First Aid instead of Sketchy. B because Sketchy does the learning; this is where you test it. MCQMicro MCQs on the VaultRun the pages you covered, the same night

Micro, as cardsThe FA Foundation Anki micro deck: 271 cards, page by page off First Aid. Opens straight into the deck.

Open the micro deck β†’
Course

CBoards & Beyond

Why: good teaching in places, but not anchored to First Aid, and Sketchy already fills the micro slot.

boardsbeyond.com ↗

Mnemonics

CPixorize

Why: the picture mnemonics are good in places, but the slot is already filled: Sketchy does this job for micro.

pixorize.com ↗

Free playlist

CAJmonics Β· Microbiology

Why: free, but Sketchy already does this job better. ▶AJmonics Β· MicrobiologyPlaylist
Long-form

DNinja Nerd Β· Microbiology

Why: long videos. For micro, that's a bad trade for your hours when Sketchy covers a bug in minutes. ▶Ninja Nerd Β· MicrobiologyPlaylist
Course

FKaplan

Why: the same reason it's F on the Step 1 list. Long, and not built around First Aid.

The micro NBMEs actually askedThe NBME Booster micro deck: 348 cards from NBME 20 to 34 and the Free 120. Revise it before your next form.

Open micro Booster β†’
The top of every list, on a schedule

Want a day-by-day schedule that tells you exactly what to study next? The Vault builds it around your exam date.

USMLE Vault day-by-day schedule Build my schedule on usmlevault.com/schedule β†’
The top of every list, already in one place.
The First Aid Guide, both Anki decks (FA Foundation and NBME Booster), the free PDFs and your schedule. Renal is free.
Open usmlevault.com β†’
usmlevault.com/schedule Β· free for your first 3 days
Read next

Sketchy Micro in 6 days — about 20 bugs a day.

Micro by system — the bugs inside each system.

All of antibiotics in 90 minutes — the drugs that kill them.

The pharmacology tier list — the same logic, for drugs.

USMLE Vault Β· The USMLE Micro Resources Tier List Β· Created 2026-10-26
USMLE Vault Try the Vault free for 3 daysStart free trial
←Back to all guides