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Updated: Aug 24, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

Genomic Characterization of a Multidrug-Resistant Serratia marcescens Isolate Recovered from a Neonatal Meningitis

Husam Al-Hraishawi1, Namariq Al-Saadi2, Shilan Jabbar3

  • 1Physiology department, College of Medicine, University of Misan, Misan, Iraq. husam.mcm@uomisan.edu.iq.

Current Microbiology
|August 22, 2026
PubMed

Insights

This study presents the first whole-genome sequencing of a multidrug-resistant Serratia marcescens (S. marcescens) strain from Iraq. The findings reveal key antimicrobial resistance genes and genetic divergence, crucial for understanding hospital-acquired infections.

Area of Science:

  • Microbiology
  • Genomics
  • Infectious Diseases

Background:

  • Serratia marcescens (S. marcescens) is a significant opportunistic pathogen causing severe hospital-acquired infections, especially in neonatal intensive care units.
  • Multidrug resistance in S. marcescens poses a growing threat to patient outcomes.

Purpose of the Study:

  • To perform whole-genome sequencing and characterization of a multidrug-resistant S. marcescens isolate (NOA1) from a neonate with meningitis in Iraq.
  • To identify antimicrobial resistance genes and understand the genetic basis of resistance in this clinical isolate.

Main Methods:

  • Identification using VITEK® 2 system and 16S rRNA gene sequencing.
  • Antimicrobial susceptibility testing to determine resistance profiles.
  • Whole-genome sequencing and comparative genomic analysis.

Main Results:

  • The S. marcescens isolate NOA1 exhibited multidrug resistance to several antibiotic classes but remained susceptible to ciprofloxacin, levofloxacin, and tigecycline.
  • Whole-genome sequencing yielded a 5.29 Mb draft genome, identifying 15 antimicrobial resistance genes, with 10 on plasmid-associated contigs.
  • Comparative genomics revealed significant genetic divergence from reference genomes, and phylogenetic analysis placed NOA1 in a distinct clinical lineage.

Conclusions:

  • Whole-genome sequencing is a powerful tool for characterizing multidrug-resistant S. marcescens.
  • Integrating phenotypic and genomic data is essential for accurate antimicrobial resistance profiling and understanding resistance dissemination mechanisms.

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