Evidence for tetracycline resistance determinant tet(M) allele replacement in a Streptococcus pneumoniae population of limited geographical origin

Int J Antimicrob Agents. 2006 Feb;27(2):159-64. doi: 10.1016/j.ijantimicag.2005.10.003. Epub 2006 Jan 19.


A collection of 185 Streptococcus pneumoniae isolates was tested for their susceptibility to antipneumococcal drugs, with a focus on the distribution of tetracycline resistance determinants tet(M) and tet(O). Resistance patterns were compared with established correlates of multidrug resistance, and tetracycline-resistant isolates were tested for clonality and allelic variation within tet(M). Resistance to tetracyclines, penicillins and macrolides were all strongly related to multidrug resistance. Over one-quarter of the strains were tetracycline resistant, all via the tet(M)-mediated mechanism. Restriction fragment length polymorphism analysis revealed a high degree of allelic variation within tet(M) and gave evidence of a clonal and horizontal spread of selected alleles. A tet(M) variant that emerged with the onset of epidemic multidrug-resistant strains was replacing old alleles in the population.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Genes, Bacterial*
  • Humans
  • Pneumococcal Infections / drug therapy
  • Pneumococcal Infections / microbiology
  • Poland
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / genetics*
  • Streptococcus pneumoniae / isolation & purification
  • Tetracycline Resistance / genetics*