mef(A)

efflux pump

Overview

Drug Classes
erythromycin, azithromycin, macrolides, macrolide
Organisms
Streptococcus pneumoniae, Streptococcus pyogenes, Bacteroides +4 more
Alleles
3
Papers
14
Mutations
5
Mutations5
Nucleotide ChangeProtein ChangeTypeEffect on FunctionResistance ToYearPaperStatus
-G65D--
azithromycin|clarithromycin
2003

Effects of an Efflux Mechanism and Ribosomal Mutations on Macrolide Susceptibility of Haemophilus influenzae Clinical Isolates.

PMID: 12604536
Not Validated
-K61Q--
azithromycin|clarithromycin
2003

Effects of an Efflux Mechanism and Ribosomal Mutations on Macrolide Susceptibility of Haemophilus influenzae Clinical Isolates.

PMID: 12604536
Not Validated
-T64K--
azithromycin|clarithromycin
2003

Effects of an Efflux Mechanism and Ribosomal Mutations on Macrolide Susceptibility of Haemophilus influenzae Clinical Isolates.

PMID: 12604536
Not Validated
-A69S--
azithromycin|clarithromycin
2003

Effects of an Efflux Mechanism and Ribosomal Mutations on Macrolide Susceptibility of Haemophilus influenzae Clinical Isolates.

PMID: 12604536
Not Validated
-T82I--
azithromycin|clarithromycin
2003

Effects of an Efflux Mechanism and Ribosomal Mutations on Macrolide Susceptibility of Haemophilus influenzae Clinical Isolates.

PMID: 12604536
Not Validated
Allele Variants3
AllelePapersDrug ClassesOrganismsCountriesYearsStatus
mef3erythromycin, azithromycin +1Streptococcus pneumoniae +2Washington State|Alaska|Canada, Hong Kong, Europe2000, 2003, 2005Not Validated
Mef(A)8macrolides, azithromycin +1Streptococcus pneumoniae +3Italy, North America|Europe|Africa|Asia, Portugal2000, 2002, 2003, 2004, 2005Not Validated
mefA3macrolides, erythromycinStreptococcus pyogenes +2Europe|North America|Asia, Ontario, Canada|Finland|Houston, Texas2003, 2005, 2023Not Validated
Papers15
1

A novel multiresistant Streptococcus pneumoniae serogroup 19 clone from Washington State identified by pulsed-field gel electrophoresis and restriction fragment length patterns.

PMID 10747146 · 2000

The study identifies a novel multiresistant Streptococcus pneumoniae serogroup 19 clone carrying the mef gene, which confers resistance to erythromycin and azithromycin.

Gene Information

Gene Name
mef(A)
Allele
mef
Encodes
efflux pump
Validation Method
restriction fragment length polymorphism (RFLP) analysis

Confers Resistance To

erythromycinazithromycin

Organisms Tested In

Streptococcus pneumoniae

Isolation Details

Country
Washington State|Alaska|Canada
2

Characterization of a genetic element carrying the macrolide efflux gene mef(A) in Streptococcus pneumoniae.

PMID 10952626 · 2000

The study characterizes the genetic element Tn1207.1 carrying the macrolide efflux gene mef(A) in Streptococcus pneumoniae, demonstrating its role in macrolide resistance through transformation and MIC testing.

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
macrolide-efflux protein
Validation Method
transformation and MIC testing

Confers Resistance To

macrolides

Organisms Tested In

Streptococcus pneumoniae
3

Antimicrobial Resistance Mechanisms and Molecular Detection Techniques

PMID 11585788 · 2023

The paper discusses molecular detection methods for antimicrobial resistance, focusing on genes like mecA and blaZ, which confer resistance to beta-lactam antibiotics in staphylococci.

Gene Information

Gene Name
mef(A)
Allele
mefA
Encodes
macrolide efflux pump
Validation Method
PCR and sequencing

Confers Resistance To

macrolides

Organisms Tested In

Streptococcus pyogenes
Streptococcus pneumoniae

Isolation Details

Country
Europe|North America|Asia
4

Emergence of group A streptococcus strains with different mechanisms of macrolide resistance.

PMID 11959545 · 2002

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
macrolide efflux pump
Validation Method
PCR

Mechanism

efflux

Confers Resistance To

azithromycin

Organisms Tested In

Streptococcus pyogenes
5

Antistreptococcal activity of telithromycin compared with seven other drugs in relation to macrolide resistance mechanisms in Russia.

PMID 12183254 · 2002

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
efflux pump
Validation Method
PCR and sequencing

Mechanism

active efflux

Confers Resistance To

macrolides

Organisms Tested In

Streptococcus pneumoniae
Streptococcus pyogenes
6

Bactericidal Effect and Pharmacodynamics of Cethromycin (ABT-773) in a Murine Pneumococcal Pneumonia Model.

PMID 12234843 · 2002

The study identified the presence of mef(A) and erm(B) genes in Streptococcus pneumoniae isolates, which confer resistance to macrolides, lincosamides, and streptogramin B. Cethromycin demonstrated effective bactericidal activity against both macrolide-susceptible and -resistant isolates.

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
macrolide efflux pump
Validation Method
susceptibility testing

Mechanism

confers resistance to macrolides by active efflux

Confers Resistance To

erythromycinazithromycin

Organisms Tested In

Streptococcus pneumoniae
7

Phenotypic and molecular characterization of tetracycline- and erythromycin-resistant strains of Streptococcus pneumoniae.

PMID 12821474 · 2003

The study identified tet(M), erm(B), mef(A), and mef(E) as the primary genes responsible for tetracycline and erythromycin resistance in Streptococcus pneumoniae strains.

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
macrolide efflux pump
Validation Method
PCR and MIC testing

Confers Resistance To

erythromycin

Organisms Tested In

Streptococcus pneumoniae

Isolation Details

Country
Italy
8

A newly discovered Bacteroides conjugative transposon, CTnGERM1, contains genes also found in gram-positive bacteria.

PMID 12902247 · 2003

The study identifies CTnGERM1, a conjugative transposon containing the erythromycin resistance gene ermG and the macrolide efflux gene mefA, which were found to confer resistance in Bacteroides and Streptococcus pyogenes.

Gene Information

Gene Name
mef(A)
Allele
mefA
Encodes
macrolide efflux protein
Validation Method
cloning and transformation experiments

Confers Resistance To

erythromycin

Organisms Tested In

Streptococcus pyogenes
Bacteroides
9

Clinical and molecular epidemiology of erythromycin-resistant beta-hemolytic lancefield group G streptococci causing bacteremia.

PMID 14605159 · 2003

The study identifies ermTR, ermB, and mef genes as mediators of erythromycin resistance in beta-hemolytic group G streptococci, highlighting the role of horizontal gene transfer in the spread of resistance.

Gene Information

Gene Name
mef(A)
Allele
mef
Encodes
efflux pump
Validation Method
PCR and DNA sequencing

Confers Resistance To

erythromycin

Organisms Tested In

Streptococcus dysgalactiae subsp. equisimilis

Isolation Details

Country
Hong Kong
10

Characterization and prevalence of MefA, MefE, and the associated msr(D) gene in Streptococcus pneumoniae clinical isolates.

PMID 15297499 · 2004

The study characterizes the MefA, MefE, and msr(D) genes in Streptococcus pneumoniae clinical isolates, demonstrating that these genes confer resistance to macrolides and ketolides. The msr(D) gene was shown to function independently as an efflux pump.

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
efflux pump
Validation Method
transformation into a susceptible strain and MIC testing

Confers Resistance To

erythromycin

Organisms Tested In

Streptococcus pneumoniae

Isolation Details

Country
North America|Europe|Africa|Asia
11

The mef(A) Gene Predominates among Seven Macrolide Resistance Genes Identified in Gram-Negative Strains Representing 13 Genera, Isolated from Healthy Portuguese Children.

PMID 15328110 · 2004

The study identified seven macrolide resistance genes in gram-negative bacteria from healthy Portuguese children, with mef(A) being the most predominant. The genes included mef(A), erm(B), ere(A), ere(B), mph(A), mph(B), and mph(D).

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
efflux protein
Validation Method
transconjugation and MIC testing

Confers Resistance To

macrolides

Organisms Tested In

Escherichia coli
Enterococcus faecalis

Isolation Details

Country
Portugal
12

The genome sequence of Salmonella enterica serovar Choleraesuis, a highly invasive and resistant zoonotic pathogen.

PMID 15781495 · 2005

The study identifies multiple antimicrobial resistance genes on plasmids pSC138 and pSCV50 in Salmonella enterica serovar Choleraesuis SC-B67, including blaTEM-1, blaCMY-2, tetRA, strA, aadA2, sulI, sulII, catI, cmlA, aph, sat, mef, mer, ebr, qac, and blaTEM-67. Additionally, mutations in the chromosomal genes gyrA and parC, along with the inactivation of acrR, contribute to ciprofloxacin resistance.

Gene Information

Gene Name
mef(A)
Allele
mef
Encodes
macrolide efflux pump
Validation Method
plasmid analysis

Confers Resistance To

macrolide

Organisms Tested In

Salmonella enterica serovar Choleraesuis

Isolation Details

Country
Europe
13

Genetic diversity among type emm28 group A Streptococcus strains causing invasive infections and pharyngitis.

PMID 16081955 · 2005

The study identified the presence of macrolide resistance genes mefA, ermB, and ermTR in less than 2% of the emm28 group A Streptococcus strains analyzed.

Gene Information

Gene Name
mef(A)
Allele
mefA
Encodes
macrolide efflux pump
Validation Method
PCR detection of gene presence

Confers Resistance To

macrolides

Organisms Tested In

Streptococcus pyogenes

Isolation Details

Country
Ontario, Canada|Finland|Houston, Texas
14

Molecular characterization of pneumococci with efflux-mediated erythromycin resistance and identification of a novel mef gene subclass, mef(I).

PMID 16304164 · 2005

The study identified a novel mef gene subclass, mef(I), in pneumococci with efflux-mediated erythromycin resistance. It also characterized the presence of tet(M) and tet(O) genes contributing to tetracycline resistance in certain isolates.

Gene Information

Gene Name
mef(A)
Allele
Mef(A)
Encodes
efflux pump
Validation Method
PCR-RFLP analysis and sequencing

Confers Resistance To

erythromycin

Organisms Tested In

Streptococcus pneumoniae

Isolation Details

Country
Italy
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