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Updated: Aug 30, 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

Acquired macrolide resistance genes in pathogenic Neisseria spp. isolated between 1940 and 1987

Sydney Cousin1, William L H Whittington, Marilyn C Roberts

  • 1Department of Pathobiology, University of Washington, Seattle, Washington 98195, USA.

Antimicrobial Agents and Chemotherapy
|November 26, 2003
PubMed

Insights

This study identified ancient antimicrobial resistance genes, including mef(A) and erm genes, in Neisseria gonorrhoeae and Neisseria meningitidis isolates dating back to the mid-20th century. These findings reveal early acquisition and potential transfer of resistance mechanisms in these bacteria.

Area of Science:

  • Microbiology and Infectious Diseases
  • Antimicrobial Resistance
  • Molecular Genetics

Background:

  • Antimicrobial resistance poses a significant global health threat.
  • Understanding the historical emergence and spread of resistance genes is crucial.
  • Neisseria gonorrhoeae and Neisseria meningitidis are important human pathogens.

Purpose of the Study:

  • To investigate the presence and historical prevalence of acquired antimicrobial resistance genes (mef(A), erm(B), erm(C), erm(F)) in early isolates of Neisseria gonorrhoeae and Neisseria meningitidis.
  • To determine the oldest known isolates carrying these specific resistance genes.
  • To explore the potential mechanisms of gene transfer for these resistance determinants.

Main Methods:

  • Screening of 76 Neisseria gonorrhoeae and 7 Neisseria meningitidis isolates (1940-1987) for specific resistance genes.
  • Utilized DNA-DNA hybridization, Polymerase Chain Reaction (PCR) analysis, and DNA sequencing.
  • Conjugation experiments with Enterococcus faecalis to assess gene transferability.

Main Results:

  • Identified mef(A), erm(B), and erm(F) genes in a 1955 Neisseria gonorrhoeae isolate and erm(C) in a 1963 isolate.
  • Detected mef(A) and erm(F) in a 1963 Neisseria meningitidis isolate; all four genes found in later isolates.
  • The mef(A) gene sequence showed 100% identity to a 1990s Streptococcus pneumoniae isolate; gene transfer to Enterococcus faecalis was observed, suggesting association with conjugative transposons.

Conclusions:

  • These findings represent the oldest documented isolates of any species carrying the mef(A) gene and among the oldest for these erm genes.
  • The presence of these genes in mid-20th-century isolates indicates early acquisition of significant antimicrobial resistance mechanisms in Neisseria species.
  • Evidence suggests that these acquired resistance genes are mobile and transferable, likely via conjugative transposons.

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