Cell wall
Penicillins · Cephalosporins · Carbapenems · Vancomycin
Canadian-focused antibiotic classification
Sort the drug.
See the pattern.
Learn common antibiotic classes by mechanism, memorable examples, typical activity patterns, and the gaps that matter. Built for health professionals and learners.
Evidence checkedAugust 15, 2026
CLASSIFICATION MAP6 TARGETS
WALL30S50SDNAFOLATE
Mechanism firstExceptions always
What this is
A memory map, not a treatment menu.
Antibiotics can be classified by the bacterial structure or process they target. That framework helps organize a large drug list, but class does not guarantee clinical activity. Infection site, susceptibility, resistance, source control, and patient factors can completely change the correct choice.
ClassWhat family?TargetWhat mechanism?PatternWhat tends to be active?GapWhat should not be assumed?
IMPORTANT
Do not use this site to select or change an antibiotic. Verify allergies, age and weight, pregnancy or lactation, kidney and liver function, interactions, cultures, infection severity, and local resistance. Seek urgent care for severe or rapidly worsening illness.
The master map
Five targets organize almost everything.
Use mechanism as the first memory shelf, then attach the clinical pattern and exceptions.
Protein 30S
AT 30 = Aminoglycosides + Tetracyclines
Protein 50S
CCEL 50 = Chloramphenicol · Clindamycin · Erythro/macrolides · Linezolid
DNA
Fluoroquinolones · Metronidazole
Folate
Trimethoprim + sulfamethoxazole block two steps
Master hookBuild the WALL · Work at the RIBOSOME · Copy DNA · Make FOLATE
Classification library
Search the common classes.
MECHANISM
Bind penicillin-binding proteins and disrupt bacterial cell-wall synthesis.
EXAMPLES
- penicillin V
- amoxicillin
- cloxacillin
- amoxicillin-clavulanate
- piperacillin-tazobactam
TYPICAL PATTERN
From narrow streptococcal activity to broad Gram-negative and anaerobic activity, depending on the agent.
IMPORTANT GAPS
No atypical coverage. Spectrum varies enormously, so the word penicillin alone is not enough.
Safety pearlClarify allergy phenotype and adjust many agents for kidney function.
Pattern recognition
Coverage shortcuts, with guardrails.
Think wall agents
Penicillins, early cephalosporins, vancomycin, linezolid, and daptomycin are memorable anchors. MRSA changes the list.
Think inside cells
Macrolides, tetracyclines, and respiratory fluoroquinolones are the classic groups.
Think oxygen-free sites
Metronidazole, beta-lactamase inhibitor combinations, carbapenems, and selected clindamycin use.
Remember PACM
Pip-tazo · Anti-pseudomonal cephalosporins · Ciprofloxacin · Meropenem. Always verify susceptibility.
Six high-yield traps
Where does the drug actually work?
Daptomycin + pneumonia
No. Lung surfactant inactivates daptomycin.
Nitrofurantoin + pyelonephritis
No. Nitrofurantoin is a bladder-focused drug.
Moxifloxacin + UTI
No. Urinary concentrations are poor.
Oral vancomycin + systemic MRSA
No. Oral absorption is minimal. It acts locally in the bowel.
Ertapenem + Pseudomonas
No. Ertapenem is the carbapenem exception.
Metronidazole + aerobic bacteria
No. Metronidazole is for anaerobes and selected protozoa.
Memory arcade
Classify it three ways.
Mechanism, site limitations, and spectrum patterns should become separate retrieval routes.
Which target shelf belongs to this drug?
amoxicillin
Drug 1 of 8Game 03 · Coverage quiz
Can you spot the pattern?
Question 1 of 5
SCORE 0/5
Which pair is the classic 30S mnemonic?
The stewardship rule
Narrowest effective agent. Correct dose. Shortest effective duration.
Antibiotics do not treat colds, influenza, COVID-19, most acute bronchitis, or most uncomplicated viral sinus symptoms. Culture when the result can change therapy, then narrow, change, or stop treatment when evidence arrives.