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nfsA

nitroreductase

NCBI Pathogen Isolates

Bacterial genomes carrying this gene

NCBI Reference Gene Catalog

Known alleles and reference sequences

Protein entries specific to nfsA

Browse AMR rules for nfsA

Validation StatusSupported

Overview

Mechanism: confers resistance to nitrofurantoin through mutations in the gene
Validation Method: PCR and sequencing
Drug Classes: Nitrofurantoin, Nitrofuran, NITROFURANTOIN
Organisms: Escherichia coli, Salmonella enterica, Salmonella enteritidis, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli K-12 substr. BW25113, Vibrio cholerae
Geographic Location: Australia, Egypt, Europe|Italy, Northwestern Transylvania, Romania, South America +1 more
Papers: 21
Databases: Reslit
Mutations: 39

Mutations

Protein Change	Nucleotide Change	Mechanism	Organism	Resistance To	Database	Validation Status
G154E	-	nitroreductase NfsA	Escherichia coli	NitrofurantoinNITROFURANTOIN	Reference Gene CatalogReslit	Confirmed
Q113*	-	-	Escherichia coli	Nitrofurantoin	Reslit	Candidate
G131D	-	nitroreductase NfsA, single resistance variant

Papers21

1

Molecular Characterisation of nfsA Gene in Nitrofurantoin Resistant Uropathogens.

PMID 27504284 · 2016

The study identifies the nfsA gene as a key factor in nitrofurantoin resistance in E. coli, with mutations such as insertions and substitutions contributing to resistance.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: confers resistance to nitrofurantoin through mutations in the gene
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Validation Method: PCR and sequencing
Sequence Accession: KR296984

2

Nonoptimal Gene Expression Creates Latent Potential for Antibiotic Resistance.

PMID 30169679 · 2018

The study identifies numerous genes whose expression changes can confer resistance to various antibiotics, highlighting the role of nonoptimal gene expression in antibiotic resistance development.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Validation Method: experimental controlled expression and MIC testing

3

Molecular mechanisms of collateral sensitivity to the antibiotic nitrofurantoin.

PMID 31986134 · 2020

The study identifies the molecular mechanisms behind collateral sensitivity to nitrofurantoin (NIT) in E. coli and S. enterica. Overexpression of nitroreductases nfsA and nfsB, along with increased antibiotic uptake in the hemL mutant, and interference with the SOS response in the lon mutant, contribute to NIT hypersensitivity.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
• Salmonella enterica
Validation Method: overexpression in E. coli and S. enterica, MIC measurements

4

Characterization of Fosfomycin and Nitrofurantoin Resistance Mechanisms in Escherichia coli Isolated in Clinical Urine Samples.

PMID 32847131 · 2020

The study identifies fosA3 as a novel plasmid-mediated fosfomycin resistance gene in E. coli isolates in Spain. Fosfomycin resistance is primarily due to defects in the UhpT transporter system, while nitrofurantoin resistance involves mutations in nfsA, nfsB, and ribE genes.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Geographic Location: Spain
Validation Method: amino acid substitution analysis

5

Antimicrobial Resistance of Salmonella enteritidis and Salmonella typhimurium Isolated from Laying Hens, Table Eggs, and Humans with Respect to Antimicrobial Activity of Biosynthesized Silver Nanoparticles.

PMID 34944331 · 2021

The study identified several AMR genes, including blaTEM, tetA, tetB, nfsA, and nfsB, in multidrug-resistant Salmonella enteritidis and Salmonella typhimurium isolates. These genes conferred resistance to ampicillin, tetracycline, and nitrofurantoin. Additionally, biosynthesized silver nanoparticles showed promising antimicrobial activity against these resistant strains.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: Nitroreductase
Source Database: Reslit
Mechanism: metabolism of nitrofurantoin
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Salmonella enteritidis
• Salmonella typhimurium
Geographic Location: Egypt
Validation Method: PCR detection of resistance genes in isolates
Sequence Accession: MT319815

6

Overcoming Multidrug Resistance in Salmonella spp. Isolates Obtained From the Swine Food Chain by Using Essential Oils: An in vitro Study.

PMID 35222307 · 2021

The study identified several AMR genes in Salmonella isolates from the swine food chain, including parC, catA1, nfsB, nfsA, blaTEM, tetA, and tetB, which confer resistance to various antibiotics such as gentamicin, amikacin, tobramycin, chloramphenicol, ampicillin, piperacillin, and tetracycline.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Salmonella enterica
Geographic Location: Europe|Italy
Validation Method: PCR detection of resistance genes

7

Exploring the in situ evolution of nitrofurantoin resistance in clinically derived uropathogenic Escherichia coli isolates.

PMID 36480295 · 2023

The study identifies loss-of-function mutations in the nitroreductase genes nfsA and nfsB as the primary mechanisms of nitrofurantoin resistance in uropathogenic E. coli. Specifically, a T37M point mutation in nfsA and a complete deletion of nfsB were found to confer resistance.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: loss-of-function mutation
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Validation Method: MIC assay and genetic manipulation

8

Pervasive Selection for Clinically Relevant Resistance and Media Adaptive Mutations at Very Low Antibiotic Concentrations.

PMID 36627817 · 2023

The study identifies clinically relevant resistance mutations in E. coli under subMIC antibiotic concentrations, showing that mutations in glpT, uhpT, uhpC, uhpA, nfsA, nfsB, gyrA, gyrB, and envZ confer resistance to fosfomycin, nitrofurantoin, ciprofloxacin, and tetracycline.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: activates nitrofurantoin
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Validation Method: whole-genome sequencing

9

CTX-M-producing Escherichia coli ST602 carrying a wide resistome in South American wild birds: Another pandemic clone of One Health concern.

PMID 37415721 · 2023

The study identifies two CTX-M-producing E. coli ST602 strains, UNB7 and GP188, from wild birds in Brazil and Chile, carrying a wide resistome against antibiotics, heavy metals, disinfectants, and herbicides.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: reduction
Organisms Tested In: • Escherichia coli
Geographic Location: South America
Validation Method: whole-genome sequencing
Sequence Accession: JAJNMH000000000|JAAVSK000000000

10

Uropathogenic Escherichia coli (UPEC)-Associated Urinary Tract Infections: The Molecular Basis for Challenges to Effective Treatment.

PMID 37764013 · 2023

This review discusses the molecular basis of challenges to effective treatment of UPEC-associated urinary tract infections, focusing on virulence factors and antibiotic resistance mechanisms.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Validation Method: mutation analysis

11

Genomic characterization of extended-spectrum beta-lactamase-producing and carbapenem-resistant Escherichia coli from urban wastewater in Australia.

PMID 38488803 · 2024

The study identifies multiple AMR genes and mutations in carbapenem-resistant and ESBL-producing E. coli isolates from Australian wastewater, highlighting the presence of resistance mechanisms such as bla NDM-5, bla CMY-42, and mutations in gyrA, parC, and parE.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: mutation leading to resistance to nitrofurantoin
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli
Geographic Location: Australia
Validation Method: genomic analysis and resistance profiling
Sequence Accession: CP079201|CP079202|CP079203|CP079204|CP079205|CP079206|CP079207|CP079208

12

Unlocking Nitrofurantoin: Understanding Molecular Mechanisms of Action and Resistance in Enterobacterales.

PMID 39471786 · 2025

The study identifies several genes and mutations associated with nitrofurantoin resistance in Enterobacterales, including nfsA, nfsB, ribE, ahpF, ribC, oqxA, oqxB, acrA, acrB, ramA, ramR, oqxR, recB, soxR, soxS, mprA, ompR, rpoA, rpoB, and CTX-M-14. These genes and mutations contribute to resistance through mechanisms such as reduced nitrofurantoin activation, efflux pump overexpression, and DNA repair defects.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitrofuran reductase
Source Database: Reslit
Mechanism: Reduction of nitrofurantoin into toxic intermediates
Organisms Tested In: • Escherichia coli
• Salmonella enterica
• Klebsiella pneumoniae
Validation Method: Mutations in the gene lead to resistance

13

The Difference a Year Can Make: How Antibiotic Resistance Mechanisms in Pseudomonas aeruginosa Have Changed in Northwestern Transylvania.

PMID 39858396 · 2024

The study identified an increase in multidrug-resistant (MDR) and extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates in Northwestern Transylvania, Romania, between 2022 and 2023. Key AMR genes included bla OXA-50, sul1, ermB, mexA, mexB, bla VIM-1, aac(6′)-II, ant(4′)-Ia, aac(3)-I, aac(6′)-Im, aph(2″)-Ib, tetA, tetC, tetK, qnrB, ermC, mphC, fosA, nfsA, nfsB, ampC, and TEM-1.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: Nitrofuran resistance protein
Source Database: Reslit
Confers Resistance To: Nitrofuran
Organisms Tested In: • Pseudomonas aeruginosa
Geographic Location: Northwestern Transylvania, Romania
Validation Method: PCR amplification and sequencing

14

Tripartite Loops Reverse Antibiotic Resistance.

PMID 40478208 · 2025

The study introduces tripartite loops consisting of three antibiotics to reverse antibiotic resistance in bacteria. By evolving resistance to a third drug, the study shows that resistance to the initial drugs can be reversed, leading to resensitization. The research highlights the role of specific genes and mutations in mediating resistance and resensitization, including genes involved in electron transport, efflux regulation, and nutrient transport.

Gene Information

Gene Name: nfsA
Allele: nfsA
Encodes: nitroreductase
Source Database: Reslit
Mechanism: involved in NIT resistance
Confers Resistance To: Nitrofurantoin
Organisms Tested In: • Escherichia coli K-12 substr. BW25113
Validation Method: genomic sequencing and MIC testing