Related Experiment Video

Updated: May 26, 2025

Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
09:44

Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing

Published on: December 23, 2022

2.1K

Colistin-resistant Escherichia coli mediated by the mcr-1 gene from pigs in northeastern Argentina

Juan Leandro Pellegrini1, María de Los Ángeles González2, Liliana Silvina Lösch1

  • 1Instituto de Medicina Regional, Universidad Nacional del Nordeste, Av. Las Heras 727 CP 3500, Resistencia, Chaco, Argentina.

Revista Argentina De Microbiologia
|February 21, 2025
PubMed

Insights

Multidrug-resistant Escherichia coli carrying the mcr-1 gene were found in 16.4% of pig farms in Argentina. These resistant E. coli strains show high multidrug resistance and clonal diversity, necessitating ongoing surveillance.

Area of Science:

  • Veterinary Microbiology
  • Antimicrobial Resistance
  • Public Health

Background:

  • The emergence of multidrug-resistant (MDR) Escherichia coli strains, particularly those carrying the mcr-1 gene conferring colistin resistance, poses a significant global public health threat.
  • Colistin is a critical last-resort antibiotic, and its efficacy is compromised by the spread of resistance genes like mcr-1.

Purpose of the Study:

  • To determine the prevalence of the mcr-1 gene in colistin-resistant E. coli isolates from commercial pig farms in Chaco, Argentina.
  • To characterize the antimicrobial resistance profiles and clonality of these E. coli isolates.

Main Methods:

  • Rectal swab samples were collected from pigs across six farms between 2020 and 2021.
  • Antimicrobial susceptibility testing was performed using broth microdilution.
  • Multiplex PCR was employed to detect mcr-1 to mcr-5 genes, and clonality was assessed via ERIC and REP-PCR.

Main Results:

  • The mcr-1 gene was detected in 16.4% of the E. coli isolates; mcr-2 to mcr-5 genes were not found.
  • Colistin resistance showed a bimodal distribution (MIC50, MIC90: 4, 8 μg/ml).
  • A high proportion (87%) of isolates were multidrug-resistant (MDR), exhibiting various resistance patterns and significant clonal diversity.

Conclusions:

  • A substantial prevalence of the mcr-1 gene was identified in colistin-resistant E. coli from pig farms in Chaco, Argentina, even in the absence of colistin use.
  • The mcr-1 positive E. coli isolates demonstrated alarming levels of multidrug resistance and genetic diversity.
  • Continuous monitoring of the mcr-1 gene in livestock, human, and environmental populations is crucial to mitigate the spread of antimicrobial resistance.
Keywords:
Antimicrobial resistanceCerdosColistinColistinaEscherichia coliPigsResistencia antimicrobianamcr-1

More Related Videos

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat08:27

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Published on: October 29, 2014

10.9K
Producing Gene Deletions in Escherichia coli by P1 Transduction with Excisable Antibiotic Resistance Cassettes08:13

Producing Gene Deletions in Escherichia coli by P1 Transduction with Excisable Antibiotic Resistance Cassettes

Published on: September 1, 2018

17.0K

Related Concept Videos

Genomic DNA in Prokaryotes00:46

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the nucleoid. The chromosome is tightly wound, or supercoiled, for efficient storage. Prokaryotes also contain other circular pieces of DNA called plasmids. These plasmids are smaller than the chromosome and often carry genes that confer adaptive functions, such as antibiotic resistance.
Genomic Diversity in Bacteria
Although bacterial genomes are much...
43.3K
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
61.7K