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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
09:00

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance

Published on: May 2, 2018

Prevalence of the multiple antibiotic resistance operon (marRAB) in the genus Salmonella

N I Kunonga1, R J Sobieski, S S Crupper

  • 1Division of Biological Sciences, Emporia State University, 1200 Commercial, Box 4050, Emporia, KS 66801, USA.

FEMS Microbiology Letters
|June 17, 2000
PubMed

Insights

The multiple antibiotic resistance (marRAB) operon is widespread in Salmonella, conferring resistance to various antibiotics. Judicious antimicrobial use is crucial to prevent the induction of multidrug resistance (mdr) in these bacteria.

Area of Science:

  • Microbiology
  • Genetics
  • Molecular Biology

Background:

  • The multiple antibiotic resistance (marRAB) operon is a key component of multidrug resistance (mdr) systems.
  • While conserved in Enterobacteriaceae, the presence of marRAB in Salmonella species was previously uncertain.

Purpose of the Study:

  • To investigate the conservation and function of the marRAB operon within the Salmonella genus.
  • To determine if Salmonella isolates exhibit multidrug resistance upon induction of the marRAB operon.

Main Methods:

  • PCR, Southern blot, and dot blot analyses were used to detect the marRAB operon in 30 Salmonella isolates.
  • DNA sequencing was performed on an amplified marRAB fragment from S. enteritidis.
  • Antimicrobial resistance profiling was conducted after induction with tetracycline or chloramphenicol.

Main Results:

  • PCR detected the marRAB operon in 16 out of 30 isolates, yielding a 2.3-kb amplicon.
  • Sequencing revealed 99% homology of the S. enteritidis marRAB fragment to that of S. typhimurium.
  • Southern and dot blot analyses confirmed the presence of marRAB in all 30 examined Salmonella species.
  • Induction with low-level antibiotics resulted in increased resistance to unrelated antimicrobial agents.

Conclusions:

  • The marRAB operon is widely distributed across Salmonella species.
  • Induction of marRAB confers a multidrug resistance phenotype in Salmonella.
  • Prudent antimicrobial usage is essential to mitigate the spread of multidrug resistance in Salmonella.

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