Browse AMR Genes

Explore antimicrobial resistance genes from the literature

blaSED

beta-lactamase

NCBI Pathogen Isolates

Bacterial genomes carrying this gene

NCBI Reference Gene Catalog

Known alleles and reference sequences

Protein entries specific to blaSED

Browse AMR rules for blaSED

Validation StatusConfirmed2+ DBs

Overview

Mechanism: Enzymatic inactivation
Validation Method: purification and kinetic analysis
Drug Classes: Penicillin, Carboxypenicillins, Cephalosporins, TICARCILLIN, AMOXICILLIN, AMPICILLIN+CLAVULANIC ACID, AMPICILLIN, BETA-LACTAM, AMOXICILLIN+CLAVULANIC ACID, PIPERACILLIN+TAZOBACTAM, PIPERACILLIN, Cefotaxime, Carbapenem, Ceftazidime, Cephalosporin
Organisms: Citrobacter sedlakii, Citrobacter farmeri, Citrobacter sedlakii NIH2339, Escherichia coli
Geographic Location: Israel, Japan, Portugal
Alleles: 4
Papers: 5
Databases: Card DatabaseReference Gene CatalogResFinder DatabaseReslit

Allele Variants4

Allele	Database	Papers	Drug Classes	Organisms	Countries	Years	Sequence Accession	Protein Accession
bla_Sed-1	Reslit	2	Penicillin, Carboxypenicillins +3	Citrobacter sedlakii +1	Japan	2001, 2025	AF321607\|AF321608	-
blaSED-1

Papers5

1

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus.

PMID 11451687 · 2001

The study identifies a novel class A beta-lactamase, Sed-1, from Citrobacter sedlakii, which confers resistance to penicillins, carboxypenicillins, and early cephalosporins.

Gene Information

Gene Name: blaSED
Allele: bla_Sed-1
Encodes: beta-lactamase
Source Database: Reslit
Confers Resistance To: PenicillinCarboxypenicillinsCephalosporins
Organisms Tested In: • Citrobacter sedlakii
Validation Method: purification and kinetic analysis
Sequence Accession: AF321607|AF321608

2

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus.

PMID 11451687 · 2001

Gene Information

Gene Name: blaSED
Allele: blaSED-1
Encodes: broad-spectrum class A beta-lactamase SED-1
Source Database: Reference Gene Catalog
Mechanism: Enzymatic inactivation
Confers Resistance To: TICARCILLINAMOXICILLINAMPICILLIN+CLAVULANIC ACIDAMPICILLINBETA-LACTAMAMOXICILLIN+CLAVULANIC ACIDPIPERACILLIN+TAZOBACTAMPIPERACILLIN
Organisms Tested In: • Citrobacter sedlakii
Sequence Accession: AF321608.1
Protein Accession: AAK63223.1
Notes: Chromosomal

3

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus.

PMID 11451687 · 2001

Gene Information

Gene Name: blaSED
Allele: blaSED-1
Encodes: broad-spectrum class A beta-lactamase SED-1
Source Database: ResFinder Database
Mechanism: Enzymatic inactivation
Confers Resistance To: TICARCILLINAMOXICILLINAMPICILLIN+CLAVULANIC ACIDAMPICILLINBETA-LACTAMAMOXICILLIN+CLAVULANIC ACIDPIPERACILLIN+TAZOBACTAMPIPERACILLIN
Organisms Tested In: • Citrobacter sedlakii
Sequence Accession: AF321608.1
Protein Accession: AAK63223.1
Notes: Chromosomal

4

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus.

PMID 11451687 · 2001

Gene Information

Gene Name: blaSED
Allele: blaSED-1
Encodes: broad-spectrum class A beta-lactamase SED-1, SED beta-lactamase
Source Database: Card Database
Mechanism: Enzymatic inactivation, antibiotic inactivation
Confers Resistance To: TICARCILLINAMOXICILLINAMPICILLIN+CLAVULANIC ACIDAMPICILLINBETA-LACTAMAMOXICILLIN+CLAVULANIC ACIDPIPERACILLIN+TAZOBACTAMPIPERACILLIN
Organisms Tested In: • Citrobacter sedlakii
Sequence Accession: AF321608.1
Protein Accession: AAK63223.1
Notes: Chromosomal, ARO:3003561

5

Novel class A beta-lactamase Sed-1 from Citrobacter sedlakii: genetic diversity of beta-lactamases within the Citrobacter genus.

PMID 11451687 · 2001

Gene Information

Gene Name: blaSED
Allele: BlaSED-1
Source Database: ResFinder Database
Mechanism: Enzymatic inactivation
Confers Resistance To: TICARCILLINAMOXICILLINAMPICILLIN+CLAVULANIC ACIDAMPICILLINAMOXICILLIN+CLAVULANIC ACIDPIPERACILLIN+TAZOBACTAMPIPERACILLIN
Organisms Tested In: • Citrobacter sedlakii
Sequence Accession: AF321608
Notes: Chromosomal

6

An Update on Wastewater Multi-Resistant Bacteria: Identification of Clinical Pathogens Such as Escherichia coli O25b:H4-B2-ST131-Producing CTX-M-15 ESBL and KPC-3 Carbapenemase-Producing Klebsiella oxytoca.

PMID 33799747 · 2021

The study identifies several AMR genes, including bla CTX-M-15, bla KPC-3, aac(6')-Ib-cr5, and various dfr and aad genes, in wastewater isolates, highlighting the prevalence of multidrug-resistant bacteria in wastewater treatment plants.

Gene Information

Gene Name: blaSED
Allele: blaSED-1
Encodes: extended-spectrum beta-lactamase
Source Database: Reslit
Mechanism: hydrolysis of beta-lactam antibiotics
Confers Resistance To: Cefotaxime
Organisms Tested In: • Citrobacter farmeri
Geographic Location: Portugal
Validation Method: PCR and sequencing
Sequence Accession: CP050115|CP050116

7

Paradoxical carbapenemase activity detected by modified carbapenemase inactivation (mCIM) method in Citrobacter sedlakii.

PMID 40853113 · 2025

The study identifies blaSED-1, a chromosomal class A beta-lactamase, as the cause of paradoxical carbapenemase activity in Citrobacter sedlakii NIH2339, despite the absence of known carbapenemase genes.

Gene Information

Gene Name: blaSED
Allele: blaSED-1
Encodes: chromosomal class A serine beta-lactamase
Source Database: Reslit
Confers Resistance To: Carbapenem
Organisms Tested In: • Citrobacter sedlakii NIH2339
Validation Method: whole-genome sequencing and LC-MS/MS
Sequence Accession: GCA_902377535.1

8

Unique Regulation of Sed-1 beta-lactamase in Citrobacter sedlakii: Insights on Resistance to Third-Generation Cephalosporin.

PMID 40868019 · 2025

The study identifies bla_Sed-1 as a beta-lactamase gene in Citrobacter sedlakii that confers resistance to ceftazidime and cefotaxime. Mutations in bla_Sed-1, including Pro167Gln, Asp179Gly, and Ile173Met, Pro174Ala, 174_175insS, enhance resistance to ceftazidime by expanding substrate specificity.

Gene Information

Gene Name: blaSED
Allele: bla_Sed-1
Encodes: beta-lactamase
Source Database: Reslit
Confers Resistance To: CeftazidimeCefotaxime
Organisms Tested In: • Citrobacter sedlakii
• Escherichia coli
Geographic Location: Japan
Validation Method: cloning in E. coli + MIC testing
Sequence Accession: BAAHNL01000000.1

9

A single amino acid substitution in SED-2 beta-lactamase leads to increased inhibitor resistance and an extended substrate spectrum.

PMID 41143423 · 2025

The study identifies SED-2, a beta-lactamase with a single amino acid substitution (Q274R) that increases resistance to third-generation cephalosporins and reduces susceptibility to clavulanic acid.

Gene Information

Gene Name: blaSED
Allele: blaSED-2
Encodes: class A chromosomal beta-lactamase
Source Database: Reslit
Mechanism: hydrolysis of β-lactam ring
Confers Resistance To: CephalosporinCeftazidime
Organisms Tested In: • Citrobacter sedlakii
• Escherichia coli
Geographic Location: Israel
Validation Method: cloning in E. coli + antibiotic susceptibility testing
Sequence Accession: AF321608