ampicillin

CHEBI:28971 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

A penicillin in which the substituent at position 6 of the penam ring is a 2-amino-2-phenylacetamido group. — ChEBI

Machine-generated and unreviewed. Identity, structure and cross-references come straight from ChEBI's and CARD's own data; no curator has signed off on this record yet.

Classification

penicillin beta-lactamARO:3000008

Strictly broader compounds or drug classes this molecule belongs to.

penicillin CHEBI:17334
β-lactam antibiotic CHEBI:27933
penicillin allergen CHEBI:88187
penicillin beta-lactam ARO:3000008

Chemical structure

Computed structure properties
Molecular formula	C16H19N3O4S
Charge	0
Average mass	349.412 Da
Monoisotopic mass	349.10963 Da
Source	ChEBI
InChIKey	AVKUERGKIZMTKX-NJBDSQKTSA-N

SMILES

[H][C@]12SC(C)(C)[C@H](C(=O)O)N1C(=O)[C@H]2NC(=O)[C@H](N)c1ccccc1

InChI

InChI=1S/C16H19N3O4S/c1-16(2)11(15(22)23)19-13(21)10(14(19)24-16)18-12(20)9(17)8-6-4-3-5-7-8/h3-7,9-11,14H,17H2,1-2H3,(H,18,20)(H,22,23)/t9-,10-,11+,14-/m1/s1

Also called

ampicilina (INN)— chebi
ampicilline (INN)— chebi
ampicillinum (INN)— chebi
6β-[(2R)-2-amino-2-phenylacetamido]-2,2-dimethylpenam-3α-carboxylic acid (EXACT_SYNONYM)— chebi
(2S,5R,6R)-6-{[(2R)-2-AMINO-2-PHENYLETHANOYL]AMINO}-3,3-DIMETHYL-7-OXO-4-THIA-1-AZABICYCLO[3.2.0]HEPTANE-2-CARBOXYLIC ACID (EXACT_SYNONYM)— chebi
(2S,5R,6R)-6-{[(2R)-2-amino-2-phenylacetyl]amino}-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (EXACT_SYNONYM)— chebi
(2S,6R)-6-{[(2R)-2-amino-2-phenylethanoyl]amino}-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid (EXACT_SYNONYM)— chebi
6-(D-(2-amino-2-phenylacetamido))-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid (EXACT_SYNONYM)— chebi
ABPC (EXACT_SYNONYM)— chebi
AMP (EXACT_SYNONYM)— chebi
AP (EXACT_SYNONYM)— chebi
Ampicillin (EXACT_SYNONYM)— chebi
Anhydrous ampicillin (EXACT_SYNONYM)— chebi
D-(−)-6-(α-aminophenylacetamido)penicillanic acid (EXACT_SYNONYM)— chebi
D-(−)-ampicillin (EXACT_SYNONYM)— chebi
aminobenzylpenicillin (EXACT_SYNONYM)— chebi
ampicillin acid (EXACT_SYNONYM)— chebi
ampicillin anhydrous (EXACT_SYNONYM)— chebi
Principen (EXACT_SYNONYM)— aro

Cross-references

Identifiers for this same structure in other resources. An accession that lands on two different structures in this corpus is withheld from both rather than shown here, since it names at most one of them.

Drug registries

Identifiers that name a drug rather than a structure. One of these can cover a parent compound, its salts and its stereoisomers, which this corpus keeps as separate records, so it is not an equivalence of structure.

Patents and articles

Documents about this compound. A patent covers a class and an article covers a topic; neither identifies a structure.

Activity roles

Every antimicrobial role a source asserts for this compound — the unreduced evidence behind its antimicrobial_class.

antimicrobial agent CHEBI:33281
antibacterial drug CHEBI:36047

Source concepts

Every upstream concept that resolved to this record. The merge is the product: this is what shows ChEBI and CARD are describing the same structure.

Upstream concepts merged into this record
Source	Native ID	Label	Minted CURIE	Version
ARO	`ARO:3000637`	ampicillin	`antibioticmech:aro-60a0e570fd`	2026-08-30
CHEBI	`CHEBI:28971`	ampicillin	`antibioticmech:chebi-ae6873a4e5`	2026-08-30

Molecular targets

The molecular entity or process this compound acts on. Each target carries evidence — this is a mechanistic claim, not a classification.

beta-lactam sensitive penicillin-binding protein PROTEIN DIRECT_BINDING_TARGET

ARO:3000749

CARD/ARO database assertion; target organism, strain, and assay are not specified. Penicillin-binding proteins are asserted as inhibited transpeptidases. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000749 (CARD/ARO asserts targeted_by_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)

Activity spectrum

Measured or curated activity against specific taxa. A number without a method is not an observation — every row here carries an assay.

21 observations · Browse all observations · Complete record (JSON.gz)

Activity observations
Organism	Activity	MIC	Disk diffusion	Assay	Strain	Sample/genome	Evidence
Enterococcus faecium NCBITaxon:1352	—	64.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0783	BioSample SAMN15040082	Evidence Page data (JSON.gz)
Escherichia coli NCBITaxon:562	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0349	BioSample SAMN11953777	Evidence Page data (JSON.gz)
Klebsiella pneumoniae NCBITaxon:573	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0497	BioSample SAMN11953783	Evidence Page data (JSON.gz)
Klebsiella aerogenes NCBITaxon:548	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0074	BioSample SAMN04014915	Evidence Page data (JSON.gz)
Escherichia coli NCBITaxon:562	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0346	BioSample SAMN11953774	Evidence Page data (JSON.gz)
Klebsiella pneumoniae NCBITaxon:573	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1149	BioSample SAMN34111336	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1150	BioSample SAMN34111337	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1151	BioSample SAMN34111338	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1152	BioSample SAMN34111339	Evidence Page data (JSON.gz)
Klebsiella pneumoniae NCBITaxon:573	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1153	BioSample SAMN34111340	Evidence Page data (JSON.gz)
Klebsiella pneumoniae NCBITaxon:573	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1158	BioSample SAMN34111344	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1160	BioSample SAMN34111346	Evidence Page data (JSON.gz)
Escherichia coli NCBITaxon:562	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1162	BioSample SAMN34111348	Evidence Page data (JSON.gz)
Klebsiella pneumoniae NCBITaxon:573	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1163	BioSample SAMN34111349	Evidence Page data (JSON.gz)
Citrobacter freundii NCBITaxon:546	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0637	BioSample SAMN10055345	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1329	BioSample SAMN50502208	Evidence Page data (JSON.gz)
Enterobacter cloacae complex NCBITaxon:354276	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	1331	BioSample SAMN50502209	Evidence Page data (JSON.gz)
Enterococcus faecium NCBITaxon:1352	—	128.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0500	BioSample SAMN11953784	Evidence Page data (JSON.gz)
Escherichia coli NCBITaxon:562	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35.	0495	BioSample SAMN11953781	Evidence Page data (JSON.gz)
Escherichia coli NCBITaxon:562	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35 per the CDC/FDA AR Isolate Bank Panel 10 footnote.	0538	BioSample SAMN11953785	Evidence Page data (JSON.gz)
Salmonella enterica subsp. enterica serovar Typhimurium NCBITaxon:90371	—	>32.0 mg/L	—	Broth microdilution ampicillin MIC; modal MIC reported; interpreted using CLSI 2025 M100 S35 per the CDC/FDA AR Isolate Bank Panel 10 footnote.	0539	BioSample SAMN07688908	Evidence Page data (JSON.gz)

Resistance mechanisms

37 source-backed resistance determinants or associations, with ARO grounding where reported. Grouped by reported mechanism type.

ANTIBIOTIC_INACTIVATION 31

ANTIBIOTIC_INACTIVATION
Determinant	ARO ID	Organism	Gene families	Evidence
AMZ-1	ARO:3007694	not organism-specific	—	ARO:3007694 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
CAE-1	ARO:3007635	not organism-specific	—	ARO:3007635 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
CMY-2	ARO:3002013	not organism-specific	—	ARO:3002013 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
CTX-M-15	ARO:3001878	not organism-specific	—	ARO:3001878 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
CTX-M-27	ARO:3001889	not organism-specific	—	ARO:3001889 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
CTX-M-3	ARO:3001866	not organism-specific	—	ARO:3001866 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
EBR-5	ARO:3007437	not organism-specific	—	ARO:3007437 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
KBL-1	ARO:3007206	not organism-specific	—	ARO:3007206 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
LAQ-1	ARO:3007438	not organism-specific	—	ARO:3007438 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
NmcA	ARO:3003589	not organism-specific	—	ARO:3003589 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
OXA-1	ARO:3001396	not organism-specific	—	ARO:3001396 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
OXA-2	ARO:3001397	not organism-specific	—	ARO:3001397 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
OXA-50	ARO:3001796	not organism-specific	—	ARO:3001796 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
PDC-3	ARO:3002500	not organism-specific	—	ARO:3002500 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
PDC-5	ARO:3002502	not organism-specific	—	ARO:3002502 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
PJM-1	ARO:3007374	not organism-specific	—	ARO:3007374 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
PRC-1	ARO:3007085	not organism-specific	—	ARO:3007085 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
PSZ-1	ARO:3007648	not organism-specific	—	ARO:3007648 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
SHV-1	ARO:3001059	not organism-specific	—	ARO:3001059 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
SSA	ARO:3007442	not organism-specific	—	ARO:3007442 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
TEM beta-lactamase	ARO:3000014	not organism-specific	—	ARO:3000014 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
TEM-1	ARO:3000873	not organism-specific	—	ARO:3000873 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
TEM-103	ARO:3000966	not organism-specific	—	ARO:3000966 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
TEM-30	ARO:3000900	not organism-specific	—	ARO:3000900 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
VAM-1	ARO:3007062	not organism-specific	—	ARO:3007062 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
VHH-1	ARO:3007003	not organism-specific	—	ARO:3007003 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
VHW-1	ARO:3007004	not organism-specific	—	ARO:3007004 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
VIM-63	ARO:3005511	not organism-specific	—	ARO:3005511 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
VMB-1	ARO:3005015	not organism-specific	—	ARO:3005015 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
WUS-1	ARO:3007435	not organism-specific	—	ARO:3007435 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
blaS1	ARO:3005111	not organism-specific	—	ARO:3005111 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)

ANTIBIOTIC_EFFLUX 3

ANTIBIOTIC_EFFLUX
Determinant	ARO ID	Organism	Gene families	Evidence
AcrAB-TolC	ARO:3000384	not organism-specific	—	ARO:3000384 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
MexAB-OprM	ARO:3000386	not organism-specific	—	ARO:3000386 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
mdeA	ARO:3007011	not organism-specific	—	ARO:3007011 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)

ANTIBIOTIC_TARGET_ALTERATION 2

ANTIBIOTIC_TARGET_ALTERATION
Determinant	ARO ID	Organism	Gene families	Evidence
Haemophilus influenzae PBP3 conferring resistance to beta-lactam antibiotics	ARO:3004446	not organism-specific	—	ARO:3004446 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)
Streptococcus pyogenes PBP2x conferring resistance to beta-lactam antibiotics	ARO:3007531	not organism-specific	—	ARO:3007531 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)

REDUCED_PERMEABILITY 1

REDUCED_PERMEABILITY
Determinant	ARO ID	Organism	Gene families	Evidence
Klebsiella pneumoniae OmpK35	ARO:3003966	not organism-specific	—	ARO:3003966 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:3000637 (ampicillin); database assertion, not a primary citation.)

Curation history

SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Seeded from data/raw/ inventories (ARO, CHEBI)
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources
Re-seeded from updated data/raw/ inventories
RESEEDED_FROM_SOURCES 2026-09-10 · seed_from_sources
Re-seeded from updated data/raw/ inventories
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Enterococcus faecium isolate MIC observation.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Escherichia coli isolate MIC observation.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Klebsiella pneumoniae isolate MIC observation.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Klebsiella aerogenes isolate MIC observation.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Corrected the CDC/FDA AR Isolate Bank 0349 breakpoint context from CLSI 2024 M100 S34 to CLSI 2025 M100 S35.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Fixes #286. Corrected the CDC/FDA AR Isolate Bank 0074 breakpoint context from CLSI 2024 M100 S34 to CLSI 2025 M100 S35.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Escherichia coli MIC observation from isolate 0346.
CURATED_RESISTANT_TAXA 2026-09-12 · codex · LLM-assisted
Added 9 stable-URL CDC/FDA AR Isolate Bank ampicillin-resistant Multi-Mechanism panel MIC observations for AR-1149, AR-1150, AR-1151, AR-1152, AR-1153, AR-1158, AR-1160, AR-1162, and AR-1163.
CURATED_RESISTANT_TAXA 2026-09-13 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Citrobacter freundii MIC observation for AR-0637.
CURATED_RESISTANT_TAXA 2026-09-17 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Enterobacter cloacae complex MIC observation for AR-1329.
CURATED_RESISTANT_TAXA 2026-09-17 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Enterobacter cloacae complex MIC observation for AR-1331.
CURATED_RESISTANT_TAXA 2026-09-17 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Enterococcus faecium MIC observation for AR-0500.
CURATED_RESISTANT_TAXA 2026-09-17 · codex · LLM-assisted
Added one stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Escherichia coli MIC observation for AR-0495.
CURATED_RESISTANT_TAXA 2026-09-20 · codex · LLM-assisted
Added two stable-URL CDC/FDA AR Isolate Bank Panel 10 ampicillin-resistant Escherichia coli and Salmonella Typhimurium MIC observations for AR-0538 and AR-0539; preserved BioSamples SAMN11953785/SAMN07688908, Study IDs NEW-22/NEW-23, and source Stool for AR-0539 in evidence notes.
STRUCTURED_ACTIVITY_BIOSAMPLE_ACCESSIONS 2026-09-26 · codex · LLM-assisted
Structured BioSample accessions on 21 activity_spectrum observation(s) where evidence notes already named exactly one accession.

Provenance

Seeded by scripts/seed_from_sources.py from the committed inventories in data/raw/. View the record (YAML).

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