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IncFII plasmid carrying antimicrobial resistance genes in Shigella flexneri: Vehicle for dissemination

Dhiviya Prabaa Muthuirulandi Sethuvel1, Shalini Anandan1, Naveen Kumar Devanga Ragupathi1

  • 1Department of Clinical Microbiology, Christian Medical College, Vellore 632 004, Tamil Nadu, India.

Journal of Global Antimicrobial Resistance
|October 22, 2018
PubMed
Abstract

Insights

Multidrug-resistant Shigella flexneri commonly carry IncFII plasmids with various antimicrobial resistance genes (ARGs). Understanding these plasmid types is crucial for tracking resistance spread in enteric bacteria.

Area of Science:

  • Microbiology
  • Genetics
  • Public Health

Background:

  • Plasmids carrying antimicrobial resistance determinants (ARGs) in clinical strains pose a global public health threat.
  • Shigella flexneri is a significant enteric pathogen, and its multidrug-resistant (MDR) forms are of particular concern.

Purpose of the Study:

  • To investigate the types of plasmids and associated antimicrobial resistance genes in clinical isolates of Shigella flexneri.
  • To enhance understanding of resistance dissemination mechanisms in enteric bacteria.

Main Methods:

  • Analysis of 162 Shigella isolates from stool specimens, with 27 multidrug-resistant (MDR) S. flexneri isolates selected for further characterization.
  • Identification of antimicrobial resistance genes (ARGs) and plasmid incompatibility (Inc) types using PCR.
  • Whole-genome sequencing of a representative IncFII-type plasmid (pSF470) and plasmid multi-locus sequence typing (pMLST).

Main Results:

  • IncFII plasmids were prevalent, found in 63% (17/27) of the studied S. flexneri isolates.
  • Common ARGs detected included dhfr1a (81%), sulII (74%), blaOXA (74%), blaTEM (33%), blaAmpC (30%), qnrS (15%), and qnrB (4%). blaCTX-M was not detected.
  • Sequencing of pSF470 revealed multiple ARGs (e.g., blaTEM1-B, blaDHA-1, qnrB10, mphA, sulI, sulII, strA, strB, tetR) and the intI1 integrase gene; pMLST identified the replicon as F2:A-:B- type.

Conclusions:

  • The study identifies prevalent plasmid types, particularly IncFII, in MDR Shigella isolates.
  • Findings underscore the importance of studying plasmids and ARGs in enteric bacteria for understanding and combating antimicrobial resistance dissemination.
Keywords:
IncFII plasmidShigella flexneribla(DHA)bla(TEM)mphAqnrS

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