nalidixic acid

CHEBI:100147 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

A monocarboxylic acid comprising 1,8-naphthyridin-4-one substituted by carboxylic acid, ethyl and methyl groups at positions 3, 1, and 7, respectively. An orally administered antibacterial, it is used in the treatment of lower urinary-tract infections due to Gram-negative bacteria, including the majority of E. coli, Enterobacter, Klebsiella, and Proteus species. — ChEBI

Classification

fluoroquinolone antibioticARO:0000001

Strictly broader compounds or drug classes this molecule belongs to.

• Label unavailable CHEBI:25384
• Label unavailable CHEBI:73537
• quinolone antibiotic CHEBI:86324
• fluoroquinolone antibiotic ARO:0000001

Chemical structure

SMILES

CCn1cc(C(=O)O)c(=O)c2ccc(C)nc21

InChI

InChI=1S/C12H12N2O3/c1-3-14-6-9(12(16)17)10(15)8-5-4-7(2)13-11(8)14/h4-6H,3H2,1-2H3,(H,16,17)

Also called

• acide nalidixique (INN)— chebi
• acido nalidixico (INN)— chebi
• acidum nalidixicum (INN)— chebi
• 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 1,4-dihydro-1-ethyl-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 1-Aethyl-7-methyl-1,8-naphthyridin-4-on-3-karbonsaeure (EXACT_SYNONYM)— chebi
• 1-Ethyl-7-methyl-4-oxo-1,4-dihydro-[1,8]naphthyridine-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 1-ethyl-7-methyl-1,4-dihydro-1,8-naphthyridin-4-one-3-carboxylic acid (EXACT_SYNONYM)— chebi
• 3-carboxy-1-ethyl-7-methyl-1,8-naphthyridin-4-one (EXACT_SYNONYM)— chebi
• NALIDIXIC ACID (EXACT_SYNONYM)— chebi
• Nalidixic acid (EXACT_SYNONYM)— chebi
• nalidixin (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.

• nalidixic acidARO:3000661
• cas:389-08-2
• kegg.compound:C05079
• lincs.smallmolecule:LSM-5590
• pdb-ccd:NIX
• reaxys:750515
• vsdb:1880
• chembl:CHEMBL5
• pubchem.compound:4421

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.

• drugbank:DB00779
• drugcentral:1875
• kegg.drug:D00183

Patents and articles

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

• patent:BE612258
• patent:US3590036
• wikipedia.en:Nalidixic_Acid

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.

Molecular targets

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

fluoroquinolone sensitive gyrA PROTEIN DIRECT_BINDING_TARGET

ARO:3000733

CARD/ARO database assertion; target organism, strain, and assay are not specified. ARO explicitly describes ligand binding to gyrase subunit A. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

• ARO:3000733 (CARD/ARO asserts targeted_by_antibiotic ARO:3000661 (nalidixic acid); database assertion, not a primary citation.)

DNA topoisomerase 4 subunit A [V210L]/B PROTEIN_COMPLEX MEASURED_TARGET_ASSOCIATION

BindingDB quantitative measurement in the named target organism; source assay descriptions and identifiers are retained per measurement. Evidence status: PRIMARY_EVIDENCE. Source: BINDINGDB 2026-09 (retrieved 2026-08-31).

Bacillus subtilis NCBITaxon:1423

• PMID:17074800 (BindingDB literature-curated quantitative target measurement; source value, assay text, reaction-set ID, and target organism retained.)

Mechanism summary

Mode of action

NUCLEIC_ACID_SYNTHESIS_INHIBITION microbial target — CURATOR: Confirmed as bacterial DNA gyrase poisoning after primary nalidixic acid mechanism review. PMID:200930.

Clinical status

APPROVED

Resistance mechanisms

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

Causal graphs

Evidence-backed mechanism graphs: how the compound reaches its target, what the target does, and how the effect propagates to growth inhibition or death.

Nalidixic acid poisons bacterial DNA gyrase MECHANISTIC

Nalidixic acid acts on the GyrA-containing bacterial DNA gyrase complex, trapping a protein-linked DNA cleavage state that blocks completion of DNA topology-changing reactions.

Curation history

1. SEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Seeded from data/raw/ inventories (ARO, CHEBI)

2. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

3. RESEEDED_FROM_SOURCES 2026-08-30 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

4. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

5. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

6. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

7. RESEEDED_FROM_SOURCES 2026-08-31 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

8. CURATED_CAUSAL_GRAPH 2026-09-04 · codex · LLM-assisted

   Added a PMID-supported causal graph for nalidixic acid poisoning of bacterial DNA gyrase and marked the coarse target scope as curator-reviewed.

9. RESEEDED_FROM_SOURCES 2026-09-10 · seed_from_sources

   Re-seeded from updated data/raw/ inventories

10. RESEEDED_FROM_SOURCES 2026-10-16 · seed_from_sources

    Re-seeded; changed: resistance_mechanisms (CARD). Upstream retrieval date 2026-08-30, unchanged.

11. CURATED_UNIPROT_PROTEIN_EXAMPLES 2026-10-18 · antigravity · LLM-assisted

    Added curated E. coli K-12 DNA gyrase subunit A (P0AES4) and subunit B (P0AES6) UniProtKB protein examples on the nalidixic_acid_gyrase_cleavage_complex dna_gyrase causal graph node.

Provenance

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

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