levofloxacin

CHEBI:63598 ·resolve ·ANTIBACTERIAL ·EXACT SEEDED

An optically active form of ofloxacin having (S)-configuration; an inhibitor of bacterial topoisomerase IV and DNA gyrase. — 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

fluoroquinolone antibioticARO:0000001

Strictly broader compounds or drug classes this molecule belongs to.

CHEBI:194135 CHEBI:194135
CHEBI:86324 CHEBI:86324
CHEBI:87211 CHEBI:87211
ARO:0000001 ARO:0000001

Chemical structure

Computed structure properties
Molecular formula	C18H20FN3O4
Charge	0
Average mass	361.373 Da
Monoisotopic mass	361.14378 Da
Source	ChEBI
InChIKey	GSDSWSVVBLHKDQ-JTQLQIEISA-N

SMILES

C[C@H]1COc2c(N3CCN(C)CC3)c(F)cc3c(=O)c(C(=O)O)cn1c23

InChI

InChI=1S/C18H20FN3O4/c1-10-9-26-17-14-11(16(23)12(18(24)25)8-22(10)14)7-13(19)15(17)21-5-3-20(2)4-6-21/h7-8,10H,3-6,9H2,1-2H3,(H,24,25)/t10-/m0/s1

Also called

levofloxacine (INN)— chebi
levofloxacino (INN)— chebi
levofloxacinum (INN)— chebi
(3S)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid (EXACT_SYNONYM)— chebi
(-)-Ofloxacin (EXACT_SYNONYM)— chebi
(3S)-(-)-9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid (EXACT_SYNONYM)— chebi
(S)-(-)-9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzooxazine-6-carboxylic acid (EXACT_SYNONYM)— chebi
(S)-9-Fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido(1,2,3-de)-1,4-benzoxazine-6-carboxylic acid (EXACT_SYNONYM)— chebi
(S)-ofloxacin (EXACT_SYNONYM)— chebi
(−)-ofloxacin (EXACT_SYNONYM)— chebi
DR 3355 (EXACT_SYNONYM)— chebi
DR-3355 (EXACT_SYNONYM)— chebi
L-ofloxacin (EXACT_SYNONYM)— chebi
Ofloxacin S-(-)-form (EXACT_SYNONYM)— chebi
S-(−)-ofloxacin (EXACT_SYNONYM)— chebi
Levaquin (EXACT_SYNONYM)— aro
Tavanic (EXACT_SYNONYM)— aro

Cross-references

Equivalent identifiers for this same structure in other resources.

ARO:0000071
cas:100986-85-4
drugbank:DB01137
drugcentral:1569
hmdb:HMDB0001929
kegg.compound:C07660
kegg.drug:D08120
lincs.smallmolecule:LSM-5270
pdb-ccd:LFX
reaxys:5385660
vsdb:1899
wikipedia.en:Levofloxacin
chembl:CHEMBL5315124
pubchem.compound:149096

Activity roles

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

CHEBI:33281 CHEBI:33281
CHEBI:36047 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:0000071`	levofloxacin	`antibioticmech:aro-825bdb3c2e`	2026-08-30
CHEBI	`CHEBI:63598`	levofloxacin	`antibioticmech:chebi-a88ec56d37`	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.

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:0000071 (levofloxacin); database assertion, not a primary citation.)

Fluoroquinolone sensitive parC PROTEIN DIRECT_BINDING_TARGET

ARO:3000735

CARD/ARO database assertion; target organism, strain, and assay are not specified. ParC is asserted as the fluoroquinolone-sensitive subunit. Evidence status: PRIMARY_EVIDENCE_NEEDED. Source: CARD_ARO 2026-08-30 (retrieved 2026-08-30).

ARO:3000735 (CARD/ARO asserts targeted_by_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)

Mechanism summary

Mode of action: NUCLEIC_ACID_SYNTHESIS_INHIBITION microbial target — Assigned from ChEBI role CHEBI:50750 (EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor), CHEBI:53559 (topoisomerase IV inhibitor), CHEBI:59517 (DNA synthesis inhibitor). ChEBI asserts the role on the compound. The role names a target specific to the microbe or virus — see mode_of_action_target_scope. Not a curator's mechanistic review.

Resistance mechanisms

35 known routes by which microbes resist this compound, grounded in ARO where CARD models them. Grouped by mechanism type — expand a group to see its determinants.

ANTIBIOTIC_TARGET_ALTERATION 30

ANTIBIOTIC_TARGET_ALTERATION
Determinant	ARO ID	Organism	Gene families	Evidence
Acinetobacter baumannii gyrA conferring resistance to fluoroquinolones	ARO:3003817	not organism-specific	—	ARO:3003817 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Acinetobacter baumannii parC conferring resistance to fluoroquinolones	ARO:3003818	not organism-specific	—	ARO:3003818 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Bartonella bacilliformis gyrA conferring resistance to fluoroquinolones	ARO:3003297	not organism-specific	—	ARO:3003297 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Capnocytophaga gingivalis gyrA conferring resistance to fluoroquinolones	ARO:3003931	not organism-specific	—	ARO:3003931 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Clostridioides difficile gyrA conferring resistance to fluoroquinolones	ARO:3003995	not organism-specific	—	ARO:3003995 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Clostridioides difficile gyrB conferring resistance to fluoroquinolones	ARO:3004562	not organism-specific	—	ARO:3004562 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Cutibacterium acnes gyrA conferring resistance to fluoroquinolones	ARO:3003974	not organism-specific	—	ARO:3003974 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Escherichia coli gyrA conferring resistance to fluoroquinolones	ARO:3003294	not organism-specific	—	ARO:3003294 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Escherichia coli parC conferring resistance to fluoroquinolones	ARO:3003308	not organism-specific	—	ARO:3003308 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Escherichia coli parE conferring resistance to fluoroquinolones	ARO:3003316	not organism-specific	—	ARO:3003316 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Helicobacter pylori gyrA conferring resistance to fluoroquinolones	ARO:3007052	not organism-specific	—	ARO:3007052 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Helicobacter pylori gyrB conferring resistance to fluoroquinolones	ARO:3007053	not organism-specific	—	ARO:3007053 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Morganella morganii gyrB conferring resistance to fluoroquinolones	ARO:3003306	not organism-specific	—	ARO:3003306 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium avium gyrA with mutation conferring resistance to fluoroquinolone	ARO:3007473	not organism-specific	—	ARO:3007473 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium leprae gyrA conferring resistance to fluoroquinolones	ARO:3003298	not organism-specific	—	ARO:3003298 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium leprae gyrB conferring resistance to fluoroquinolones	ARO:3003304	not organism-specific	—	ARO:3003304 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium tuberculosis gyrA conferring resistance to fluoroquinolones	ARO:3003295	not organism-specific	—	ARO:3003295 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium tuberculosis gyrA mutations conferring resistance to levofloxacin	ARO:3007809	not organism-specific	—	ARO:3007809 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium tuberculosis gyrB mutations conferring resistance to levofloxacin	ARO:3007810	not organism-specific	—	ARO:3007810 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycobacterium tuberculosis gyrB with mutation conferring resistance to fluoroquinolones	ARO:3003459	not organism-specific	—	ARO:3003459 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Mycoplasma hominis parC conferring resistance to fluoroquinolones	ARO:3003310	not organism-specific	—	ARO:3003310 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Pseudomonas aeruginosa gyrA conferring resistance to fluoroquinolones	ARO:3003684	not organism-specific	—	ARO:3003684 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Salmonella serovars gyrB conferring resistance to fluoroquinolones	ARO:3003307	not organism-specific	—	ARO:3003307 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Salmonella serovars parE conferring resistance to fluoroquinolones	ARO:3003317	not organism-specific	—	ARO:3003317 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Staphylococcus aureus gyrA conferring resistance to fluoroquinolones	ARO:3003296	not organism-specific	—	ARO:3003296 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Staphylococcus aureus parC conferring resistance to fluoroquinolones	ARO:3003312	not organism-specific	—	ARO:3003312 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Staphylococcus aureus parE conferring resistance to fluoroquinolones	ARO:3003315	not organism-specific	—	ARO:3003315 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Streptococcus pneumoniae parC conferring resistance to fluoroquinolones	ARO:3003311	not organism-specific	—	ARO:3003311 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Ureaplasma urealyticum gyrB conferring resistance to fluoroquinolones	ARO:3003305	not organism-specific	—	ARO:3003305 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Ureaplasma urealyticum parC conferring resistance to fluoroquinolones	ARO:3003309	not organism-specific	—	ARO:3003309 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)

ANTIBIOTIC_EFFLUX 3

ANTIBIOTIC_EFFLUX
Determinant	ARO ID	Organism	Gene families	Evidence
Acinetobacter baumannii AbaQ	ARO:3004574	not organism-specific	—	ARO:3004574 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
QepA3	ARO:3004378	not organism-specific	—	ARO:3004378 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)
Rv1877	ARO:3007662	not organism-specific	—	ARO:3007662 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)

ANTIBIOTIC_TARGET_PROTECTION 1

ANTIBIOTIC_TARGET_PROTECTION
Determinant	ARO ID	Organism	Gene families	Evidence
quinolone resistance protein (qnr)	ARO:3000419	not organism-specific	—	ARO:3000419 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)

ANTIBIOTIC_TARGET_REPLACEMENT 1

ANTIBIOTIC_TARGET_REPLACEMENT
Determinant	ARO ID	Organism	Gene families	Evidence
Helicobacter pylori rpoB mutation conferring resistance to rifampicin	ARO:3007051	not organism-specific	—	ARO:3007051 (CARD/ARO asserts confers_resistance_to_antibiotic ARO:0000071 (levofloxacin); database assertion, not a primary citation.)

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.

Levofloxacin poisons bacterial topoisomerase IV MECHANISTIC

Levofloxacin stabilizes a bacterial topoisomerase IV-DNA cleavage complex, blocking resealing of the enzyme-linked DNA break and disrupting chromosome topology control.

Nodes — levofloxacin_topoisomerase_iv_poisoning
Node	Label	Type	Grounding
`levofloxacin`	levofloxacin	COMPOUND	`CHEBI:63598`
`topoisomerase_iv`	bacterial topoisomerase IV	GENE_OR_PROTEIN	`ARO:3000735`
`topoiv_dna_cleavage_complex`	topoisomerase IV covalent DNA cleavage complex	STATE	REVIEWED_LABEL_ONLY
`dna_religation`	topoisomerase IV DNA religation	MOLECULAR_FUNCTION	REVIEWED_LABEL_ONLY
`dna_topology_control`	bacterial chromosome decatenation and topology control	BIOLOGICAL_PROCESS	REVIEWED_LABEL_ONLY

Edges — levofloxacin_topoisomerase_iv_poisoning
Subject	Predicate	Object	Evidence
`levofloxacin`	stabilizes	`topoiv_dna_cleavage_complex`	PMID:27050128 (Veselkov and colleagues resolved levofloxacin-stabilized topoisomerase IV-DNA cleavage complexes from Klebsiella pneumoniae and Streptococcus pneumoniae.)
`topoisomerase_iv`	participates in	`topoiv_dna_cleavage_complex`	PMID:27050128 (The same structures contain ParC and ParE domains with DNA and levofloxacin.)
`topoiv_dna_cleavage_complex`	inhibits	`dna_religation`	PMID:27050128 (Levofloxacin was resolved in cleaved topoisomerase IV-DNA complexes, the trapped state preceding break religation.)
`dna_religation`	supports	`dna_topology_control`	PMID:27050128 (The topoisomerase IV structure study describes the levofloxacin-stabilized target as a bacterial type II topoisomerase needed for chromosome topology.)

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
CURATED_CAUSAL_GRAPH 2026-09-04 · codex · LLM-assisted
Added a PMID-supported causal graph for levofloxacin poisoning of bacterial topoisomerase IV.

Provenance

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