Antibiotic and antiseptic resistance genes are linked on a novel mobile genetic element: Tn6087

J Antimicrob Chemother. 2011 Oct;66(10):2235-9. doi: 10.1093/jac/dkr311. Epub 2011 Aug 3.

Abstract

Objectives: Tn916-like elements are one of the most common types of integrative and conjugative element (ICE). In this study we aimed to determine whether novel accessory genes, i.e. genes whose products are not involved in mobility or regulation, were present on a Tn916-like element (Tn6087) isolated from Streptococcus oralis from the human oral cavity.

Methods: A minocycline-resistant isolate was analysed using restriction fragment length polymorphism (RFLP) analysis on amplicons derived from Tn916 and DNA sequencing to determine whether there were genetic differences in Tn6087 compared with Tn916. Mutational analysis was used to determine whether the novel accessory gene found was responsible for an observed extra phenotype.

Results: A novel Tn916-like element, Tn6087, is described that encodes both antibiotic and antiseptic resistance. The antiseptic resistance protein is encoded by a novel small multidrug resistance gene, designated qrg, that was shown to encode resistance to cetyltrimethylammonium bromide (CTAB), also known as cetrimide bromide.

Conclusions: This is the first Tn916-like element described that confers both antibiotic and antiseptic resistance, suggesting that selection of either antibiotic or antiseptic resistance will also select for the other and further highlights the need for prudent use of both types of compound.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Anti-Infective Agents, Local / pharmacology*
  • Bacterial Proteins / genetics
  • Base Sequence
  • Cetrimonium
  • Cetrimonium Compounds / pharmacology
  • Conjugation, Genetic
  • DNA, Bacterial / genetics
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Gene Transfer, Horizontal
  • Humans
  • Interspersed Repetitive Sequences*
  • Microbial Sensitivity Tests
  • Minocycline / pharmacology
  • Mutation
  • Polymorphism, Restriction Fragment Length
  • Sequence Analysis, DNA
  • Streptococcus oralis / drug effects*
  • Streptococcus oralis / genetics*
  • Tetracycline Resistance / genetics

Substances

  • Anti-Bacterial Agents
  • Anti-Infective Agents, Local
  • Bacterial Proteins
  • Cetrimonium Compounds
  • DNA, Bacterial
  • Minocycline
  • Cetrimonium