Description of a novel mutation in the atpC gene in optochin-resistant Streptococcus pneumoniae strains isolates from Tunisia

Int J Antimicrob Agents. 2018 May;51(5):803-805. doi: 10.1016/j.ijantimicag.2017.12.029. Epub 2018 Jan 3.

Abstract

Identification of Streptococcus pneumoniae among other α-haemolytic streptococci is based on phenotypic or genotypic characteristics such as colony morphology, bile solubility and optochin susceptibility. This study reports three optochin-resistant S. pneumoniae strains isolated from immunocompromised patients in Tunisia. The three isolates were positive for the bile solubility test. Biochemical identification with API® 20 Strep was not discriminatory for two strains. The three strains had different serotypes (6C, 19F and 23F) and three different sequence types (ST386, ST320 and ST326). Sequencing of the atpA and atpC genes for each strain showed only modification in atpC. The mutations Met13→Val or Val48→Ile were observed in two strains. However, in the third strain a novel type of mutation (Val15→Ile) was identified.

Keywords: Mutation; Optochin resistance; Streptococcus pneumoniae; atpC gene.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics*
  • Drug Resistance, Bacterial / drug effects
  • Drug Resistance, Bacterial / genetics*
  • Humans
  • Microbial Sensitivity Tests
  • Mutation*
  • Pneumococcal Infections / microbiology
  • Quinine / analogs & derivatives*
  • Quinine / pharmacology
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / genetics
  • Streptococcus pneumoniae / isolation & purification
  • Tunisia

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • ethylhydrocupreine
  • Quinine