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USMLE Vault · Step 1

Microbiology by System

Microbiology is not one subject to be conquered. It is nine finite lists, each one attached to a system you are already studying.

Studied as a single block, micro has no edges. You open the chart, scan the whole thing, and an hour disappears without a single organism actually revised — because nothing on the page told you where to stop.

Split by organ system, it has edges everywhere. Neurology is 31 organisms. Dermatology is 7. When you finish the list, the list is finished, and "done" becomes a fact rather than a feeling.

There is a second reason, and it is the better one. You already study Step 1 system by system. Doing the neurology organisms in the same week as neurology pathology means the bug and the disease get encoded together — which is exactly how the exam asks about them.

The nine system lists

Each page carries the organisms that matter for that system — whichever classes apply to it — grouped, numbered, and followed by the WRWRT method applied to one organism in full so you know what each step looks like before you repeat it.

SystemOrganismsList
Neurology31micro-cns →
Immunology28micro-immuno →
Gastrointestinal24micro-git →
Cardiovascular18micro-cvs →
Respiratory15micro-respi →
Reproductive14micro-repro →
Renal11micro-renal →
Dermatology7micro-derm →
Musculoskeletal7micro-msk →
Read the counts before you start. Dermatology and MSK are 7 organisms each — an evening, not a week. Neurology and immunology are where the hours actually go. Plan the block around that, not around the alphabet.

All nine lists are columns of the same source chart. If you want the whole grid on one screen — searchable, filterable by the organism classes relevant to that system — that is the SystemWise Micro chart.

The method every list uses: WRWRT

Same five steps, every organism, in order. The order is the point — each step only works because of the one before it.

StepWhat it does
WWatch, 1x, no notesWalk the memory palace without stopping at every door
RRecall the story, chronologically, in your headThe only step that builds retrieval — and the one everyone skips
WWatch again — only the gaps, 1.5–1.75xYour failed recall just mapped where the time should go
RRead the Sketchy Micro PDF for those organismsConverts the image into sentences, because the exam asks in words
TTest with the FA Guide MCQs for those exact organismsTells you the truth about the previous four

If you want it as a full day-by-day run rather than system by system, that is the six-day Sketchy Micro protocol — same method, different container.

Never touched Sketchy? Every one of these lists can be revised from First Aid alone. The list is still your list; only the source changes.

Then the drugs

Organisms without the drugs that kill them is half a block. The antimicrobials page runs the same shape — a finite group list and a method — as FWRT rather than WRWRT: the 6 antimicrobial drug groups →

It belongs to the wider pharm block, which is built on the same stratification logic: complete pharmacology in 48 hours.

How to actually use this

1
Pick the system you are studying this week. Not the shortest one, not the first one — the one your First Aid reading is already on.
2
Open that list and work down it. WRWRT on each organism. Do not go back to the chart mid-list; the chart is what made you lose the hour in the first place.
3
Stop when the list ends. Completion over perfection. The retention comes later, when UWorld puts one of these in a vignette and the visual story comes straight back.
Do this today: open the system you are currently on, count the organisms, and do WRWRT on the first one properly — all five steps, including the recall you will want to skip. One organism done properly tells you how long the whole list will take.
Where this sits in the plan.
→ Not sure a system is actually finished? When is a system actually finished.
→ The micro block as a standalone sprint: Sketchy Micro in 6 days.
→ The drugs half of the same block: Pharmacology in 48 hours.
Nine lists. One method. Finite either way.
The organism lists, the FA Guide MCQs and the Sketchy Micro PDF are all inside the Vault.
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