# Microbiology by System — nine lists, one method

> Microbiology split into nine organ-system organism lists, each with a fixed count and the same five-step WRWRT method, plus the antimicrobials drug-group page.

URL: https://usmlevault.com/blog/micro-by-system.html
Canonical: https://usmlevault.com/blog/micro-by-system.html

## Summary

A hub for studying USMLE Step 1 microbiology system by system rather than as one undifferentiated subject. The argument is that micro studied as a block has no edges — you scan the chart and lose an hour without revising anything — whereas each organ-system column is a finite, countable list you can finish. It also aligns micro with the system you are already reading in First Aid, so the organism and the disease are encoded together. Every system page carries its organism list grouped into the organism classes relevant to that system, followed by the WRWRT method worked through on one organism in full.

## Key facts

- Nine system lists, with organism counts: Neurology 31, Immunology 28, Gastrointestinal 24, Cardiovascular 18, Respiratory 15, Reproductive 14, Renal 11, Dermatology 7, Musculoskeletal 7
- Each list is one column of the SystemWise Micro chart at https://usmlevault.com/resources/systemwise-micro.html, which is searchable and filterable by the organism classes relevant to that system
- WRWRT is the method used on every organism: Watch at 1x with no notes; Recall the story chronologically in your head; Watch again only the gaps at 1.5–1.75x; Read the Sketchy Micro PDF for those organisms; Test with the FA Guide MCQs for those exact organisms
- The recall step is the one most students skip and the only one that builds retrieval
- Every list can be revised from First Aid alone if the student has never used Sketchy; only the source changes, not the list
- The antimicrobials companion page covers 6 drug groups and uses FWRT rather than WRWRT: https://usmlevault.com/resources/pharm-antimicrobials.html
- Working order: pick the system your First Aid reading is already on, work down the list, stop when the list ends — completion over perfection
- System pages: micro-cns, micro-immuno, micro-git, micro-cvs, micro-respi, micro-repro, micro-renal, micro-derm, micro-msk, all at https://usmlevault.com/resources/

## Covers

microbiology by system usmle, systemwise micro, wrwrt method, sketchy micro system wise, micro organism list by organ system, step 1 microbiology plan, antimicrobials step 1, how to finish microbiology

## Source

USMLE Vault — https://usmlevault.com
Author: Dr. Marish Asudani

Updated: 2026-09-14